| 1. |
- Akhras, Michael, et al.
(författare)
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Connector Inversion Probe Technology : A Powerful One- Primer Multiplex DNA Amplification System for Numerous Scientific Applications
- 2007
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 2:9, s. e915-
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Tidskriftsartikel (refereegranskat)abstract
- We combined components of a previous assay referred to as Molecular Inversion Probe (MIP) with a complete gap filling strategy, creating a versatile powerful one-primer multiplex amplification system. As a proof-of-concept, this novel method, which employs a Connector Inversion Probe (CIPer), was tested as a genetic tool for pathogen diagnosis, typing, and antibiotic resistance screening with two distinct systems: i) a conserved sequence primer system for genotyping Human Papillomavirus (HPV), a cancer-associated viral agent and ii) screening for antibiotic resistance mutations in the bacterial pathogen Neisseria gonorrhoeae. We also discuss future applications and advances of the CIPer technology such as integration with digital amplification and next-generation sequencing methods. Furthermore, we introduce the concept of two-dimension informational barcodes, i. e. "multiplex multiplexing padlocks'' (MMPs). For the readers' convenience, we also provide an on-line tutorial with user-interface software application CIP creator 1.0.1, for custom probe generation from virtually any new or established primer-pairs.
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| 2. |
- Aspholm, Marina, et al.
(författare)
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Helicobacter pylori adhesion to carbohydrates
- 2006
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Ingår i: Methods in Enzymology. - 0076-6879 .- 1557-7988. ; 417, s. 293-339
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Tidskriftsartikel (refereegranskat)abstract
- Adherence of bacterial pathogens to host tissues contributes to colonization and virulence and typically involves specific interactions between bacterial proteins called adhesins and cognate oligosaccharide (glycan) or protein motifs in the host that are used as receptors. A given pathogen may have multiple adhesins, each specific for a different set of receptors and, potentially, with different roles in infection and disease. This chapter provides strategies for identifying and analyzing host glycan receptors and the bacterial adhesins that exploit them as receptors, with particular reference to adherence of the gastric pathogen Helicobacter pylori.
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| 3. |
- Butylkina, Rita, et al.
(författare)
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Pooling of urine specimens allows accurate and cost-effective genetic detection of Chlamydia trachomatis in Lithuania and other low-resource countries
- 2007
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 39:3, s. 209-212
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to compare performance characteristics and cost-effectiveness of pooling urine samples for screening and diagnosis of Chlamydia trachomatis using Digene Hybrid Capture II CT/NG Test (HCII), and to examine the prevalence of C. trachomatis in male military recruits in Lithuania. A total of 410 urine samples were individually tested and pooled by 5 and 10 samples, respectively. The sensitivity and specificity of diagnosis were not affected by either pooling strategy. The estimated population prevalence of C. trachomatis infection was nearly identical, i.e. 4.4%, 4.4% and 4.1% based on individually tested samples, and samples pooled by 5 and 10, respectively. For this estimation of the population prevalence, pooling 5 samples reduced the costs by 80% and pooling 10 samples reduced the costs by 90%. For diagnosis of each individual sample, the pooling strategies resulted in cost savings of 60% (5 samples per pool) and 56% (10 samples per pool). The present pooling strategies were sensitive, specific and cost-efficient for screening and diagnosis of C. trachomatis infection in male military recruits in Lithuania. The strategies would be most useful for reasonably inexpensive large-scale screening, prevalence studies and even diagnostics in Lithuania and many other low-resource countries.
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| 4. |
- Domeika, Marius, et al.
(författare)
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Laboratory diagnostics for non-viral sexually transmitted infections in St. Petersburg, Russia : current situation and hallmarks for improvements
- 2008
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Ingår i: Journal of the European Academy of Dermatology and Venereology. - : Wiley. - 0926-9959 .- 1468-3083. ; 22:9, s. 1094-100
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The numbers and performance characteristics of laboratories providing sexually transmitted infection (STI) diagnostic services, as well as the rates of morbidity due to STIs in St. Petersburg, Russia, remain largely unknown. OBJECTIVE: The aim of the present study was to evaluate the range, quality and availability of diagnostic services for several non-viral STIs (Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum and Trichomonas vaginalis) in St. Petersburg during the period September 2005 to June 2006. METHODS: Survey data focusing on organization and performance characteristics of STI diagnostic services were assessed using questionnaires, telephone interviews and site visits. RESULTS: A total of 118 laboratories providing STI diagnostic services were identified. Of the surveyed laboratories, 54% (64 of 118) diagnosed syphilis, 81% (96 of 118) gonorrhoea, 80% (94 of 118) trichomoniasis and 49% (58 of 118) chlamydial infections. Although most of the laboratories could provide a presumptive diagnosis for syphilis, most of the N. gonorrhoeae and T. vaginalis testing of women did not adhere to international recommendations. Of the laboratories with the capacity to diagnose C. trachomatis infection, 69% still used serological testing (enzyme-linked immunosorbent assay) to detect antibodies to C. trachomatis. CONCLUSIONS: Overall, the diagnostic methods used to establish a laboratory diagnosis, the system of case reporting, the training of laboratory personnel and the level of interlaboratory communication clearly require improvement. This study represents the first step in a process of evaluation of the laboratory support for STI services and the establishment of an interlaboratory network in St. Petersburg.
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| 5. |
- Fjeldsoe-Nielsen, H, et al.
(författare)
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Phenotypic and genotypic characterization of prolyliminopeptidase-negative Neisseria gonorrhoeae isolates in Denmark.
- 2005
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - : Springer Science and Business Media LLC. - 0934-9723 .- 1435-4373. ; 24:4, s. 280-283
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Tidskriftsartikel (refereegranskat)abstract
- In the study presented here 26 recent Danish clinical isolates of prolyliminopeptidase (PIP)-negative Neisseria gonorrhoeae were phenotypically and genotypically characterized to investigate whether one or more PIP-negative strains are circulating in the Danish community. The profiles of these isolates were compared with those of three isolates from a recent outbreak of PIP-negative N. gonorrhoeae infection in the UK. Twenty-five of the Danish isolates and all three UK isolates had similar antibiograms and were designated serovar IB-4. Genotypic characterization by pulsed-field gel electrophoresis, porB1b gene sequencing, and opa-typing revealed that these isolates were indistinguishable or closely related. The results indicate that at least one PIP-negative N. gonorrhoeae strain is currently circulating in the Danish community, and this strain is indistinguishable from the one that caused an outbreak in the UK.
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| 6. |
- Gharizadeh, Baback, et al.
(författare)
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Detection of gyrA mutations associated with ciprofloxacin resistance in Neisseria gonorrhoeae by rapid and reliable pre-programmed short DNA sequencing
- 2005
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Ingår i: International Journal of Antimicrobial Agents. - : Elsevier BV. - 0924-8579 .- 1872-7913. ; 26:6, s. 486-490
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Tidskriftsartikel (refereegranskat)abstract
- Quinolone resistance is rapidly increasing in Neisseria gonorrhoeae and is posing a significant public health threat that requires constant surveillance. A rapid and reliable mutation detection assay has been developed. The assay is based on pre-programmed short DNA sequencing and is designed to detect point mutations in the gyrA gene that are highly related to ciprofloxacin resistance, i.e. in codons 91 and 95. By developing an assay based on pyrosequencing and exploiting the pre-programmed nucleotide dispensation capability of this technology, the sequence comprising the mutations will be analysed and promptly reveal whether the N. gonorrhoeae pathogen carries resistance to ciprofloxacin. A panel of 40 N. gonorrhoeae clinical isolates, of which 27 phenotypically displayed decreased susceptibility or resistance to ciprofloxacin, was used in the present study. All point mutations in the short stretch of the N. gonorrhoeae gyrA gene were easily discriminated, and the genotypic results obtained by pre-programmed sequencing were mainly in agreement with the phenotypically identified decreased susceptibility or resistance to ciprofloxacin. The new method used in the present study has the potential for rapid and reliable identification of known as well as previously unknown drug resistance mutations.
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| 7. |
- Hadad, Ronza, et al.
(författare)
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Evaluation of the new COBAS TaqMan CT test v2.0 and impact on the proportion of new variant Chlamydia trachomatis by the introduction of diagnostics detecting new variant C trachomatis in Örebro county, Sweden
- 2009
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Ingår i: Sexually Transmitted Infections. - London : BMJ Publishing Group. - 1368-4973 .- 1472-3263. ; 85, s. 190-193
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Tidskriftsartikel (refereegranskat)abstract
- Background: The new variant of Chlamydia trachomatis (nvCT), discovered in Sweden in 2006, contains a 377-bp cryptic plasmid deletion, which includes the targets for the COBAS Amplicor/TaqMan C trachomatis/Neisseria gonorrhoea and Abbott m2000rt C trachomatis/N gonorrhoea tests.Objectives: To evaluate the new real-time COBAS TaqMan CT test v2.0 (CTM CT v2.0) for C trachomatis diagnostics and to investigate whether the proportion of nvCT was affected by the introduction of genetic diagnostics detecting nvCT (LightMix 480HT) in Örebro county, Sweden.Methods: CTM CT v2.0 compared with LightMix 480 HT PCR for the diagnosis of C trachomatis was evaluated. Discrepant samples were analysed using BD ProbeTec ET and Abbott m2000rt RealTime CT II. All previously LightMix and cell culture-positive samples were analysed using an nvCT-specific PCR.Results: The sensitivity, specificity, negative predictive value and positive predictive value of CTM CT v2.0 for examined samples (n = 1058) was 100%, 99.8%, 100% and 98.2%, respectively. Of 11 577 consecutive PCR samples, 9.4% (n = 1084) were positive and 34.3% (n = 372) of these were nvCT. Of 2306 consecutive culture samples, 5.0% (n = 116) were C trachomatis positive and 38.8% (n = 45) of these were nvCT.Conclusions: CTM CT v2.0 is a sensitive and specific method for C trachomatis detection. Studies including larger numbers of symptomatic and asymptomatic patients as well as genital and extragenital samples, and in comparison with other internationally validated and, ideally, US Food and Drug Administration-approved C trachomatis nucleic acid amplification tests are imperative. The proportion of nvCT remains high in Örebro county, Sweden, despite the introduction of genetic diagnostics to detect the mutant.
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| 8. |
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| 9. |
- Hedberg, Sara Thulin, et al.
(författare)
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Antibiotic susceptibility and characteristics of Neisseria meningitidis isolates from the African meningitis belt, 2000 to 2006 : phenotypic and genotypic perspectives
- 2009
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 53:4, s. 1561-1566
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Tidskriftsartikel (refereegranskat)abstract
- Up-to-date information regarding the antibiotic susceptibility of Neisseria meningitidis strains from African countries is highly limited. Our aim was to comprehensively describe the antibiotic susceptibilities of a selection of N. meningitidis isolates recovered between 2000 and 2006 from 18 African countries, mainly those within the meningitis belt. Susceptibilities to 11 antibiotics were determined using Etest for 137 N. meningitidis isolates (stringently selected from 693 available isolates). The isolates were also characterized by serogrouping, multilocus sequence typing, genosubtyping, and penA allele identification. All N. meningitidis isolates were susceptible to ceftriaxone, chloramphenicol, and ciprofloxacin. No isolate produced beta-lactamase. Only three isolates (2%) displayed reduced susceptibility to penicillin G. The two isolates with the highest penicillin G MICs were the only isolates showing reduced susceptibility to ampicillin and cefuroxime. One of these isolates was also resistant to penicillin V. One percent of isolates displayed reduced susceptibility to rifampin, while 52% of the isolates were resistant to tetracycline, 74% were resistant to erythromycin, and 94% were resistant to sulfadiazine. The MICs of rifampin and tetracycline seemed to be associated with the serogroup of the isolates. In total, 18 sequence types (STs), 10 genosubtypes, and 8 different penA alleles were identified; the most common were ST-7, P1.20,9,35-1, and penA4, respectively. A high level of correlation was found between ST, genosubtype, and penA allele. In conclusion, N. meningitidis isolates from the African meningitis belt remain highly susceptible to the antibiotics used. Regarding beta-lactam antibiotics, rare isolates showed a reduced susceptibility to penicillins, but the expanded-spectrum cephalosporins are not affected at present.
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| 10. |
- Hedberg, Sara Thulin, et al.
(författare)
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Combined real-time PCR and pyrosequencing strategy for objective, sensitive, specific, and high throughput identification of reduced susceptibility to penicillins in Neisseria meningitidis
- 2008
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Ingår i: Antimicrobial Agents and Chemotherapy. - Washington, DC : American Society for Microbiology. - 0066-4804 .- 1098-6596. ; 52:2, s. 753-756
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Tidskriftsartikel (refereegranskat)abstract
- A segment of penA in Neisseria meningitidis strains (n = 127), including two nucleotide sites closely associated to reduced susceptibility to penicillins, was amplified and pyrosequenced. All results were in concordance with Sanger sequencing, and a high correlation between alterations in the two Pen(i)-specific sites and reduced susceptibility to penicillins was identified.
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| 11. |
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| 12. |
- Hellmark, Bengt, et al.
(författare)
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Antibiotic susceptibility among Staphylococcus epidermidis isolated from prosthetic joint infections with special focus on rifampicin and variability of the rpoB gene
- 2009
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Ingår i: CLINICAL MICROBIOLOGY AND INFECTION. - Oxford : Elsevier BV. - 1198-743X .- 1469-0691. ; 15:3, s. 238-244
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus epidermidis is the most important pathogen in infections related to implanted foreign materials, especially prosthetic joint infections (PJIs). The aim of this study was to investigate the antimicrobial activities of 16 antibiotics against S. epidermidis isolated from PJIs, with special focus on rifampicin and rpoB variability. Ninety-one per cent of the isolates were multiresistant (i.e. resistant to members of more than three classes of antibiotics). Thirty-nine per cent were resistant to rifampicin, associated with one or two single-nucleotide polymorphisms (SNPs) in rpoB. Using IsoSensitest agar with supplements, 61% were resistant to oxacillin, and using Mueller-Hinton II agar with supplement, 84% were resistant. Using the Etest, 58% were resistant to cefoxitin, and using the disk diffusion test, 91% were resistant. The mecA gene was detected in 85% of the isolates. Regarding recently available antibiotics, all isolates were susceptible to tigecycline and linezolid, and 97% were susceptible to daptomycin. In addition, two novel antibiotics, dalbavancin and ceftobiprole, were tested, although not yet available for routine use. The MIC50 and MIC90 values of these novel antibiotics were 0.032 and 0.047 mg/L and 0.5 and 1.5 mg/L, respectively. Among the other antibiotics, the rates of resistance varied between 0% (vancomycin) and 82% (trimethoprim-sulphamethoxazole). S. epidermidis strains causing PJIs often show multiresistance, including resistance to rifampicin, which is mainly caused by one or two SNPs. Some of the newer antimicrobial agents may provide alternatives for monotherapy or combination therapy with rifampicin. Detection of mecA is necessary before initiating treatment of infections due to S. epidermidis when it displays intermediate susceptibility to cefoxitin.
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| 13. |
- Hellmark, Bengt, et al.
(författare)
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Simultaneous species identification and detection of rifampicin resistance in staphylococci by sequencing of the rpoB gene
- 2009
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - Berlin : Springer. - 0934-9723 .- 1435-4373. ; 28:2, s. 183-190
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, coagulase-negative staphylococci (CoNS) have been increasingly recognised as causative agents of various infections, especially in immunocompromised patients and related to implanted foreign body materials. In this study, rpoB sequencing was used for simultaneous species identification and detection of rifampicin resistance in clinical staphylococci isolates. Forty-nine (96%) out of 51 isolates, representing 17 different Staphylococcus species according to the initial phenotypic species identification, were identified to the species level using rpoB sequencing. Furthermore, the two remaining isolates were Kocuria sp. and Corynebacterium sp. respectively, according to 16S rRNA sequencing. Comparison with the phenotypic diagnostics also revealed that 8 (16%) of the 49 isolates differed regarding identified species. Discrepant analysis confirmed the result of the rpoB sequencing for all except 2 of these isolates, which could not be distinguished as single species using 16S rRNA sequencing. Regarding detection of rifampicin resistance, isolates obtained pre- and post-treatment with rifampicin were examined. These isolates comprised S. aureus (7 patients) and S. lugdunensis (1 patient). Rifampicin resistance was mainly detected following short-term treatment with rifampicin in combination with isoxazolyl-penicillin, or long-term treatment with rifampicin and ciprofloxacin. Each rifampicin-resistant isolate displayed an identical rpoB sequence as their corresponding rifampicin-susceptible isolates except for one (n = 6) or two (n = 1) nonsynonymous single nucleotide polymorphisms, or insertion of one codon (n = 1). In conclusion, rpoB sequencing is a rapid, objective and accurate method of species identification and simultaneous detection of rifampicin resistance in staphylococci.
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| 14. |
- Hjelmevoll, Stig Ove, et al.
(författare)
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A fast real-time polymerase chain reaction method for sensitive and specific detection of the Neisseria gonorrhoeae porA pseudogene
- 2006
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Ingår i: Journal of Molecular Diagnostics. - : Elsevier BV. - 1525-1578 .- 1943-7811. ; 8:5, s. 574-581
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Tidskriftsartikel (refereegranskat)abstract
- Ever since the advent of molecular methods, the diagnostics of Neisseria gonorrhoeae has been troubled by false negative and false positive results compared with culture. Commensal Neisseria species and Neisseria meningitidis are closely related to N. gonorrhoeae and may cross-react when using molecular tests comprising too-low specificity. We have devised a real-time polymerase chain reaction (PCR), including an internal amplification control, that targets the N. gonorrhoeae porA pseudogene. DNA was automatically isolated on a BioRobot M48. Our subsequent PCR method amplified all of the different N. gonorrhoeae international reference strains (n = 34) and N. gonorrhoeae clinical isolates (n = 176) but not isolates of the 13 different nongonococcal Neisseria species (n = 68) that we tested. Furthermore, a panel of gram-negative bacterial (n = 18), gram-positive bacterial (n = 23), fungal (n = 1), and viral (n = 4) as well as human DNA did not amplify. The limit of detection was determined to be less than 7.5 genome equivalents/PCR reaction. In conclusion, the N. gonorrhoeae porA pseudogene real-time PCR developed in the present study is highly sensitive, specific, robust, rapid and reproducible, making it suitable for diagnosis of N. gonorrhoeae infection.
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| 15. |
- Hjelmevoll, Stig Ove, et al.
(författare)
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Clinical validation of a real-time polymerase chain reaction detection of Neisseria gonorrheae porA pseudogene versus culture techniques
- 2008
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Ingår i: Sexually Transmitted Diseases. - Philadelphia : American Venereal Disease Association. - 0148-5717 .- 1537-4521. ; 35:5, s. 517-520
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Tidskriftsartikel (refereegranskat)abstract
- Background: Diagnosing Neisseria gonorrheae using nucleic acid amplification tests (NAATs) might increase the sensitivity, compared to cultivation. However, using NAATs has also been problematic mainly due to the close genetic relationships between different Neisseria species, resulting in false positive diagnoses. This study was conducted to clinically validate a previously published real-time polymerase chain reaction (PCR) method targeting the porA pseudogene in N. gonorrheae in comparison to culture techniques.Methods: In total, 360 samples, urethra (n = 109), rectum (n = 84), pharynx (n = 119), and cervix (n = 48) from 185 males and 57 females, were analyzed using porA pseudogene PCR and cultivation. Sequencing of the entire porA pseudogene and the 16S rRNA gene were used to resolve discrepant results.Results: Of the 360 samples, 37 were positive by both culture and PCR, however, the PCR identified 15 additional confirmed positive samples. The PCR method showed a sensitivity, specificity, positive predictive value, and negative predictive value of 100% in a preselected population. The preselected population had a true gonorrhea prevalence of 17.4%.Conclusions: The present porA pseudogene real-time PCR comprises a valuable supplement to the traditional culture techniques for diagnosis of N. gonorrheae, especially for samples from extragenital sites such as pharynx and rectum.
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| 16. |
- Jacobsson, Susanne, 1974-, et al.
(författare)
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Prevalence and sequence variations of the genes encoding the five antigens included in the novel 5CVMB vaccine covering group B meningococcal disease
- 2009
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Ingår i: Vaccine. - Amsterdam : Elsevier. - 0264-410X .- 1873-2518. ; 27:10, s. 1579-1584
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Tidskriftsartikel (refereegranskat)abstract
- During the recent years, projects are in progress for designing broad-range non-capsular-based meningococcal vaccines, covering also serogroup B isolates. We have examined three genes encoding antigens (NadA, GNA1030 and GNA2091) included in a novel vaccine, i.e. the 5 Component Vaccine against Meningococcus B (5CVMB), in terms of gene prevalence and sequence variations. These data were combined with the results from a similar study, examining the two additional antigens included in the 5CVMB (fHbp and GNA2132).nadA and fHbp v. 1 were present in 38% (n=36), respectively 71% (n=67) of the isolates, whereas gna2132, gna1030 and gna2091 were present in all the Neisseria meningitidis isolates tested (n=95). The level of amino acid conservation was relatively high in GNA1030 (93%), GNA2091 (92%), and within the main variants of NadA and fHbp. GNA2132 (54% of the amino acids conserved) appeared to be the most diversified antigen. Consequently, the theoretical coverage of the 5CVMB antigens and the feasibility to use these in a broad-range meningococcal vaccine is appealing.
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| 17. |
- Jacobsson, Susanne, 1974-, et al.
(författare)
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Sequence constancies and variations in genes encoding three new meningococcal vaccine candidate antigens
- 2006
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Ingår i: Vaccine. - : Elsevier BV. - 0264-410X .- 1873-2518. ; 24:12, s. 2161-2168
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Tidskriftsartikel (refereegranskat)abstract
- By the strategy “reverse vaccinology” a number of new antigens have been identified in Neisseria meningitidis, which are potential candidates for a highly needed broad-spectrum meningococcal vaccine. In the present study we examined the prevalence, sequence constancies and variations of the genes encoding three of these new antigens designated, genome-derived neisserial antigen (GNA) 1870, GNA1946 and GNA2132. All three genes were present in all N. meningitidis isolates tested. Concerning gna1870, three major variants of the gene sequences and deduced amino acid sequences were identified and 56% of the deduced amino acids were conserved in all isolates. In gna1946, 98% of the deduced amino acids were conserved and in gna2132, 54% of the deduced amino acids were conserved. Based on gene prevalence and conservation, all three antigens are promising candidates for an effective meningococcal vaccine against all N. meningitidis irrespective of serogroup.
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| 18. |
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| 19. |
- Kubanova, A., et al.
(författare)
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National surveillance of antimicrobial susceptibility in Neisseria gonorrhoeae in 2005-2006 and recommendations of first-line antimicrobial drugs for gonorrhoea treatment in Russia
- 2008
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Ingår i: Sexually Transmitted Infections. - London : BMJ Publishing Group. - 1368-4973 .- 1472-3263. ; 84:4, s. 285-289
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate comprehensively the antimicrobial susceptibility and resistance of Neisseria gonorrhoeae during 2005-2006 in a national survey and to recommend effective antimicrobial drugs for the treatment of gonorrhoea in Russia.METHODS: The susceptibility of N gonorrhoeae isolates, cultured mainly from consecutive gonorrhoea patients (n = 1030) during the period January 2005 to December 2006 in Russia, to penicillin G, ceftriaxone, ciprofloxacin, tetracycline and spectinomycin was analysed using the agar dilution method. Nitrocefin discs were used for beta-lactamase detection.RESULTS: All isolates were susceptible to ceftriaxone. During 2005 and 2006, however, 5%, 50%, 70% and 77% displayed intermediate susceptibility or resistance to spectinomycin, ciprofloxacin, tetracycline and penicillin G, respectively. Furthermore, 4% of the isolates were beta-lactamase producing during these years. The different federal districts of Russia displayed substantial heterogeneities with regard to the prevalence of gonorrhoea and antimicrobial resistance among N gonorrhoeae isolates.CONCLUSIONS: In Russia, penicillins, ciprofloxacin, or tetracycline should definitively not be used in the empirical treatment of gonorrhoea. The recommended first-line antimicrobial drug should be ceftriaxone. If ceftriaxone is not available, spectinomycin ought to be used. Increasing levels of intermediate susceptibility and resistance to spectinomycin have, however, been observed during recent years and, accordingly, great care and monitoring should be undertaken when using this agent. Continuous local, national and international surveillance of N gonorrhoeae antimicrobial susceptibility, in order to reveal the emergence of new resistance, to monitor changing patterns of susceptibility and to be able to update treatment recommendations on a regular basis, is crucial.
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| 20. |
- Kucinskiene, Vesta, et al.
(författare)
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Home sampling and pooling of vaginal samples are effective tools for genetic screening of Chlamydia trachomatis among high school female students in Lithuania
- 2008
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Ingår i: Scandinavian Journal of Infectious Diseases. - London : Taylor & Francis. - 0036-5548 .- 1651-1980. ; 40:2, s. 88-93
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Tidskriftsartikel (refereegranskat)abstract
- The aims were 1) to estimate the prevalence of C. trachomatis infection among sexually active female students in Kaunas, Lithuania; 2) to investigate the usefulness of personal invitation, self-sampling, and pooling of samples for screening; and 3) to evaluate the costs of the approaches used. A cross-sectional study inviting 795 female students (18–31 y of age) from 7 high schools and 1 college in Kaunas was performed. The response rate was 67% (533/795). Self-obtained vaginal samples were analysed, individually and pooled (n=3), using Digene Hybrid Capture II CT/NG Test. The overall prevalence of C. trachomatis infection was 5.6%. Among the sexually active female students 20–24 y of age (n=424), the prevalence was 7.1%; however, the prevalence varied from 0% to 14.2% at the different schools. For estimation of the population prevalence based solely on identification of C. trachomatis positive pools, the pooling strategy reduced the costs by 85%. For estimation of population prevalence and for diagnosis of each individual sample, pooling reduced the costs by 70%. Targeted screening, using pooling to reduce the expenses, mainly of 3rd and 4th y Lithuanian female students could be recommended. By extended personal contact and internet-based communication, increased participation rates may be attained.
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| 21. |
- Lan, P. T., et al.
(författare)
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Reproductive tract infections including sexually transmitted infections : a population-based study of women of reproductive age in a rural district of Vietnam.
- 2008
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Ingår i: Sexually Transmitted Infections. - London : BMJ Publishing Group. - 1368-4973 .- 1472-3263. ; 84:2, s. 126-132
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate the prevalences of reproductive tract infections (RTI)/sexually transmitted infections (STI) among married women in a rural district of Vietnam, and analyse the influence of socioeconomic, sociodemographic, and other determinants possibly related to RTI/STI. Methods: A community-based cross-sectional study. Married women aged 18–49 years (n = 1012) were interviewed and underwent a gynaecological examination. Specimens were collected for laboratory diagnosis of chlamydia, gonorrhoea, trichomonas, bacterial vaginosis (BV), candidiasis, hepatitis B, HIV, and syphilis. Results: In total, 37% of the women were clinically diagnosed with an RTI/STI. Aetiologically confirmed RTI/STI was identified in 39% of the women (including 6% with STI). Endogenous infections were most prevalent (candidiasis 26%, BV 11%) followed by hepatitis B 8.3%, Chlamydia trachomatis 4.3%, Trichomonas vaginalis 1%, Neisseria gonorrhoeae 0.7%, genital warts 0.2%, and HIV and syphilis 0%. Fifty per cent of the STI cases were asymptomatic. Younger age and intrauterine devices were significantly associated with an increased risk of BV. Determinants of candidiasis were vaginal douching, high education level and low economic status, whereas a determinant of chlamydia was high economic status. Outmigration of the husband was associated with an increased risk of hepatitis B surface antigen seroposivity among women. Conclusions: RTI/STI were prevalent among married women in a rural population of Vietnam. Syndromic algorithms should be consistently supplemented by risk assessment in order to reduce under and overtreatment. Microscopic diagnosis could be applied in primary care settings to achieve more accurate diagnoses. The promotion of health education aimed at reducing RTI/STI prevalences is an important tool in STI/HIV control programmes. Vaccination to prevent hepatitis B for migrants should be considered.
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| 22. |
- Lindbäck, Emma, et al.
(författare)
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Pyrosequencing of the DNA gyrase gene in Neisseria species : effective indicator of ciprofloxacin resistance in Neisseria gonorrhoeae
- 2006
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 114:12, s. 837-841
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Tidskriftsartikel (refereegranskat)abstract
- The quinolone resistance determining region (QRDR) of the gyrA gene in ciprofloxacin-susceptible strains (n=53) and strains of Neisseria spp. with reduced susceptibility (n=70) was determined by the pyrosequencing method. Results showed that the QRDR of the gyrA gene is an effective molecular indicator of resistance to ciprofloxacin in Neisseria gonorrhoeae, and presumably in Neisseria meningitidis, but not in all other Neisseria spp. This sequence was not unique for N. gonorrhoeae and seems unsuitable for species verification of N. gonorrhoeae. However, whether it is also possible to use this region for verification depends on the specificity of the primary screening method used.
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| 23. |
- Lindbäck, Emma, et al.
(författare)
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Transformation of ciprofloxacin-resistant Neisseria gonorrhoeae gyrA, parE and porB1b genes
- 2006
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Ingår i: International Journal of Antimicrobial Agents. - : Elsevier BV. - 0924-8579 .- 1872-7913. ; 28:3, s. 206-211
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Tidskriftsartikel (refereegranskat)abstract
- In several transformation experiments, we have shown that introduction of an alteration in GyrA at position 95 of a ciprofloxacin-susceptible Neisseria gonorrhoeae strain (minimum inhibitory concentration (MIC) 0.008 mg/L) increases the MIC to 0.064 mg/L. Two alterations (positions 91 and 95) increase the MIC to 0.125-0.25 mg/L. Transformants with ciprofloxacin MICs of 0.5-16 mg/L were obtained from a moderately ciprofloxacin-resistant strain (MIC 0.25 mg/L). These transformants had alterations in the gene for PorB1b and probably other genes. In one transformant, an alteration in ParE was also introduced, which probably contributed to ciprofloxacin resistance. The ciprofloxacin-resistant transformants had the donor porB1b sequence, and most of them also had altered serovars. We conclude that alterations in N. gonorrhoeae PorB1b could be involved in ciprofloxacin resistance.
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| 24. |
- Lundbäck, David, et al.
(författare)
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Molecular epidemiology of Neisseria gonorrhoeae- identification of the first presumed Swedish transmission chain of an azithromycin-resistant strain
- 2006
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 114:1, s. 67-71
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, 10 azithromycin-resistant Neisseria gonorrhoeae isolates from 6 Swedish male patients in 2004, 3 sporadic Swedish azithromycin-resistant N. gonorrhoeae isolates from recent years and one Swedish N. gonorrhoeae isolate from 2003 that was susceptible to azithromycin but assigned the same serological variant (serovar), i.e. IB-37, as the isolates from 2004 were included. The isolates were characterized phenotypically using antibiograms and serovar determination and genetically with pulsed-field gel electrophoresis (PFGE), entire porB gene sequencing and N. gonorrhoeae multiantigen sequence typing (NG-MAST). The epidemiological information and the results of the thorough phenotypic characterisation and genetic characterisation identified the first presumed domestic transmission of one azithromycin-resistant N. gonorrhoeae strain in Sweden in 2004. This stresses the need for continuous surveillance of the antibiotic susceptibility of N. gonorrhoeae in order to identify emergence of new resistance, monitor the changing patterns of the susceptibility, and be able to update treatment recommendations on a regular basis.
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| 25. |
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| 26. |
- Olsen, Birgitta, et al.
(författare)
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A view of the Neisseria gonorrhoeae population in Sweden in 2005 : phenotypic and genetic characterisation
- 2006
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- AimsTo phenotypically and genotypically characterise clinical N. gonorrhoeae isolates transmitted in Sweden during 2005 and to compare with characteristics of N. gonorrhoeae populations in other countries.IntroductionIn Sweden, the gonorrhoea incidence decreased from the beginning of the 1970s to 1996. From 1997 the incidence has almost annually increased, mainly due to a rise in domestic cases of young heterosexuals of both sexes and homosexual men. Furthermore, during recent decades resistance to most of the traditional antibiotics used in the treatment of gonorrhoea has rapidly increased worldwide. Availability of effective diagnostics, treatment and surveillance of epidemiological characteristics (antibiotic susceptibility, serovars and genotypes) are main tools for control of the transmission of infection.Materials, Methods & ResultsN. gonorrhoeae isolates (n=175) cultured in Sweden in 2005 and received at the Swedish Reference Laboratory for Pathogenic Neisseria were included. Phenotypic characterisation was performed by antibiotic susceptibility testing and serovar determination using both Genetic systems (GS) and Pharmacia (Ph) panels of monoclonal antibodies (MAbs). Genetic characterisation was performed using N. gonorrhoeae multiantigen sequence typing (NG-MAST) that analyses more variable segments of the porB gene (490 bp) and of the tbpB gene (390 bp).All isolates were susceptible to cefixime, ceftriaxone, and spectinomycin. The levels of intermediate susceptibility and resistance to azithromycin, ciprofloxacin, and ampicillin were 2.3%, 49.7% and 75.3%, respectively (Table 1). Fifty-seven (33%) of the isolates were -lactamase producing.In total, 33 of the isolates were determined as serogroup WI (PorB1a). These were assigned nine different GS-serovars and seven different Ph-serovars. Two of the PorB1a isolates were not serotypeable using Ph MAbs. The remaining 142 isolates were determined as serogroup WII/III (PorB1b). These isolates were assigned 18 different GS-serovars and 38 different Ph-serovars.The isolates displayed 66 and 56 divergent NG-MAST porB and tbpB alleles, respectively. These resulted in assignment of 95 different sequence types (STs), of which 34 have not been previously described. ST40 (n=15), ST225 (n=12), ST1813 (n=9), ST5 (n=8), ST753 (n=6), ST323 (n=5), and ST211 (n=4), were the most prevalent STs. Four STs were represented by three isolates, 20 STs by two isolates and 64 STs by single isolates (Figure 1).ConclusionsA highly diverse N. gonorrhoeae population was transmitted in Sweden during 2005, which can reflect importation of strains from abroad, and/or in some geographic areas suboptimal diagnostics and incomplete epidemiological surveillance. However, many clusters of isolates, which can reflect the existence of several transmission chains, were also identified.Serovar determination is still fairly effective, rapid, inexpensive, easily performed and remains a valuable primary epidemiological marker of N. gonorrhoeae, which can supplement the superior genetic characterisation.
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| 27. |
- Olsen, Birgitta, et al.
(författare)
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First ever population-based assessment of Mycoplasma genitalium in Vietnam : low prevalence among married women of reproductive age in rural areas
- 2008
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To analyse the prevalence of Mycoplasma genitalium infection in a population-based study among sexually active married women from a demographic surveillance site in a rural geographical area of Vietnam.Materials and Methods: Women, 18-49 years of age, were randomly selected to participate. DNA was isolated from endocervical swabs sampled from 990 participating women. The M. genitalium MgPa adhesion gene was detected using a real-time PCR with TaqMan probeResults: Eight (0.8% [95% confidence interval, 0.25-1.35%]) of the included women were infected with M. genitalium. Two of these positive women reported clinical symptoms. One additional M. genitalium positive but symptom-free woman, however, showed clinical signs of vaginitis. None of the M. genitalium positive women was concomitantly infected with Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum or HIV. Furthermore, there was no obvious association between M. genitalium infection and vaginal douching, use of intra-uterine device (IUD), or occurrence of bacterial vaginosis, candidiasis, or Trichomonas vaginalis.Conclusions: The prevalence of M. genitalium among sexually active married women in Vietnam was relatively low. However, more large, well-designed and appropriately performed studies in other population groups including unmarried women and men, and in other geographical areas, rural as well as urban, are crucial in order to extract any evidence-based conclusions regarding the overall prevalence of STIs, including M. genitalium infections, in the Vietnamese society. The present study compiled with such future studies may form the basis for a national sexual health strategy for prevention, diagnosis, and surveillance of STIs, including M. genitalium infections, in Vietnam.
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| 28. |
- Olsen, Birgitta, 1952-, et al.
(författare)
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Population-based assessment of Mycoplasma genitalium in Vietnam : low prevalence among married women of reproductive age in a rural area
- 2009
-
Ingår i: Journal of the European Academy of Dermatology and Venereology. - Amsterdam : Wiley-Blackwell Publishing Inc.. - 0926-9959 .- 1468-3083. ; 23:5, s. 533-537
-
Tidskriftsartikel (refereegranskat)abstract
- Objective To analyse the prevalence of Mycoplasma genitalium infection in a population-based study among married women from a demographic surveillance site in a rural geographical area of Vietnam.Materials and Methods Women, 18-49 years of age, were randomly selected to participate. DNA was isolated from endocervical swabs sampled from 990 participating women. The M. genitalium MgPa adhesion gene was detected using a real-time PCR with TaqMan probe.Results Eight (0.8% [95% confidence interval, 0.25-1.35%]) of the included women were infected with M. genitalium .Two of these positive women reported clinical symptoms. One additional M. genitalium positive but symptom-free woman, however, showed clinical signs of vaginitis. None of the M. genitalium positive women was concomitantly infected with Chlamydia trachomatis , Neisseria gonorrhoeae , syphilis or HIV. Furthermore, there was no obvious association between M. genitalium infectionand vaginal douching, use of intra-uterine device (IUD), or occurrence of bacterial vaginosis, candidiasis, or Trichomonas vaginalis .Conclusions The prevalence of M. genitalium among married women in Vietnam was relatively low. However, more large, well-designed and appropriately performed studies in other population groups including unmarried women and men, and in other geographical areas, rural as well as urban, are crucial in order to extract any evidence-based conclusions regarding the overall prevalence of STIs, including M. genitalium infections, in the Vietnamese society. The present study compiled with such future studies may form the basis for a national sexual health strategy for prevention, diagnosis, and surveillance of STIs, including M. genitalium infections, in Vietnam.
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| 29. |
- Olsen, Birgitta, et al.
(författare)
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The Neisseria gonorrhoeae population in Sweden during 2005 : phenotypes, genotypes and antibiotic resistance
- 2008
-
Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - Oxford : Blackwell. - 0903-4641 .- 1600-0463. ; 116:3, s. 181-189
-
Tidskriftsartikel (refereegranskat)abstract
- In Sweden, the gonorrhoea incidence has significantly increased since an all-time low in 1996. We aimed to phenotypically and genotypically characterise N. gonorrhoeae isolates (nΩ180) transmitted in Sweden during 2005. All isolates were susceptible to cefixime, ceftriaxone, and spectinomycin. However, 2%, 50% and 75% displayed intermediate susceptibility or resistance to azithromycin, ciprofloxacin and ampicillin, respectively. The isolates were assigned to 28 different serovars using Genetic Systems monoclonal antibodies (Mabs) (discriminatory index, 91.0%) and 46 different serovars using Pharmacia Mabs (index, 94.4%). Furthermore, they displayed 95 porB sequences (index, 97.8%) and 95 N. gonorrhoeae multiantigen sequence typing (NG-MAST) sequence types (STs) (index, 98.0%). 51 (54%) of these STs have not been previously described. 14 ST clusters, comprising between 3 and 15 isolates, were identified that indicate the existence of several transmission chains. The high number of unique STs (nΩ63) may be associated with import of strains from abroad, local emergence of new STs, incomplete epidemiological surveillance, and/or suboptimal diagnostics, including contact tracing. Overall, the Swedish N. gonorrhoeae population was remarkably diversified. Comprehensive knowledge regarding transmission, phenotypes (including antibiotic resistance), but also in many cases highly discriminative and precise genotypic characteristics of the N. gonorrhoeae strains circulating in our societies, is crucial.
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| 30. |
- Parihar, Vishal Singh, et al.
(författare)
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Characterization of human invasive isolates of Listeria monocytogenes in Sweden 1986-2007
- 2008
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Ingår i: Foodborne pathogens and disease. - : Mary Ann Liebert. - 1535-3141 .- 1556-7125. ; 5:6, s. 755-761
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Tidskriftsartikel (refereegranskat)abstract
- Since 1986, 68% of the Listeria monocytogenes isolates from human cases of invasive listeriosis in Sweden are available for retrospective studies. The aim of the present study was to characterize 601 human invasive isolates of L. monocytogenes in Sweden from 1986 to 2007 by using serotyping and pulsed-field gel electrophoresis. Since 1996, serovar 4b was permanently reduced to the second or third most common serovar in human cases in Sweden. During the latter period, 2000-2007, only 13% belonged to serovar 4b and 71% to 1/2a. The dendrogram, based on pulsovars, reveals two clusters with different serovars. Cluster 1 exhibits serovars 4b and 1/2b, whereas cluster 2 consists of serovar 1/2a. Serovar 1/2a seems to be more heterogeneous than serovar 4b.
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| 31. |
- Reischl, U., et al.
(författare)
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The Swedish new variant of chlamydia trachomatis (NVCT) remains undetected by many European laboratories as revealed in the recent PCR/NAT ring trial organised by Instand ev, Germany
- 2009
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Ingår i: Eurosurveillance. - 1025-496X .- 1560-7917. ; 14:32, s. 14-17
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Tidskriftsartikel (refereegranskat)abstract
- The May 2009 round of INSTAND's ring trial "Chlamydia trachomatis detection PCR/NAT" included a sample with high amount of the Swedish new variant of C. trachomatis (nvCT). A spectrum of at least 12 different commercial diagnostic nucleic acid amplification tests (NAATs) and many different in house NAATs were applied by the 128 participating laboratories which reported 152 results. Approximately 80% of the results correctly reported the presence of C. trachomatis in the nvCT specimen. The nvCT sample was mainly missed, as expected, by participants using the Roche COBAS Amplicor CT/NG (15.5% of reported results) but also by several participants using in house NAATs. The trend towards using nvCT-detecting NAATs is obvious and in addition to the new dual-target NAATs from Roche and Abbott, and BD ProbeTec ET, also a number of new CE mark-certified commercial tests from smaller diagnostic companies as well as many different in house NAATs were used. Laboratories using commercial or in house NAATs that do not detect the nvCT are encouraged to carefully monitor their C. trachomatis incidence, participate in appropriate external quality assurance and controls schemes, and consider altering their testing system. The reliable detection of low amounts of the wildtype C. trachomatis strain in other samples of the ring trial set indicates a good diagnostic performance of all applied commercial NAATs while also detecting the nvCT strain.
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| 32. |
- Shalepo, Kira, et al.
(författare)
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Diagnosis of Chlamydia trachomatis in Russia--in-house PCR assays may be effective but overall optimization and quality assurance are urgently needed
- 2006
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 114:7-8, s. 500-507
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, the performance of the cell culture method, two non-Russian direct immunofluorescence (DIF) assays, and three different in-house polymerase chain reaction (PCR) tests used in St. Petersburg, Russia, for detection of Chlamydia trachomatis in urogenital specimens was evaluated. A total of 650 patients were examined and it was most disquieting that previous C. trachomatis positivity with Russian DIF assays could - 7 days later - be confirmed only in 26% of the women and 30% of the men. Overall, the highest diagnostic sensitivity was obtained using PCR analysis. However, the sensitivity varied significantly: from 79% to 100% between the different PCR assays, sex of the patients, and type of samples. The highest sensitivity was obtained for female vaginal and male urine samples (100%). The specificity of the PCR assays varied from 97% to 100%. The sensitivity of cell culture and both the examined DIF assays was low, i.e. it varied from 46% to 56% and 55% to 75%, respectively. Meanwhile, cell culture was 100% specific and the DIFs showed a specificity varying from 99% to 100%. In conclusion, in a Russian perspective, adequate in-house PCR methods may be used quite effectively for detection of C. trachomatis in invasive as well as non-invasive clinical material. Simultaneous analysis of two different specimens from women resulted in a significantly increased detection rate of C. trachomatis. Nevertheless, in Russia the need for optimization and quality assurance of diagnostic methods for C. trachomatis, especially Russian DIF assays, has to be emphasized.
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| 33. |
- Shipitsyna, Elena, et al.
(författare)
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Comparison of microscopy, culture and in-house PCR and NASBA assays for diagnosis of Neisseria gonorrhoeae in Russia
- 2008
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - Oxford : Blackwell. - 0903-4641 .- 1600-0463. ; 116:2, s. 133-138
-
Tidskriftsartikel (refereegranskat)abstract
- This study aimed to assess the laboratory diagnosis of Neisseria gonorrhoeae in St. Petersburg, Russia. In total, 334 consecutive symptomatic patients were enrolled. Cervical and urethral specimens from women (nΩ286) and urethral specimens from men (nΩ48) were analyzed by microscopy, culture and two in-house NAATs, i.e. polymerase chain reaction (PCR) and nucleic acid sequence-based amplification (NASBA), developed in Russia. All N. gonorrhoeae-positive samples were confirmed using porA pseudogene and 16S rRNA gene sequencing. All methods displayed 100% specificity, i.e. positive predictive values of 100%. Compared to the PCR (most sensitive method in the present study), in women the sensitivity of both microscopy and culture was 31.8%, and that of NASBA was 90.9%. In men, microscopy, culture and NASBA displayed a sensitivity of 75%, 50% and 100%, respectively. The negative predictive values of microscopy, culture, and NASBA were 97.3%, 97.3%, and 99.6% in women, and 97.8%, 95.7%, and 100% in men, respectively. According to the PCR, the prevalences of N. gonorrhoeae were 4.5% (women) and 8.3% (men). In conclusion, both the investigated Russian NAATs displayed a high sensitivity and specificity. However, in general the diagnosis of gonorrhoea in Russia is suboptimal and crucially requires validation, improvements and quality assurance.
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| 34. |
- Shipitsyna, Elena, et al.
(författare)
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First evaluation of six nucleic acid amplification tests widely used in the diagnosis of Chlamydia trachomatis in Russia
- 2009
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Ingår i: Journal of the European Academy of Dermatology and Venereology. - : Wiley. - 0926-9959 .- 1468-3083. ; 23:3, s. 268-276
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background In Russia, nationally developed nucleic acid amplification tests (NAATs), which have never been validated to international commercially available NAATs, are mainly used in the diagnosis of Chlamydia trachomatis infection. Objective To evaluate the performance characteristics of six NAATs widely used to diagnose C. trachomatis infection in Russia. Materials and methods In total, 446 consecutive symptomatic patients (319 females and 127 males) were included. Five polymerase chain reaction (PCR) assays and one real-time nucleic acid sequence-based amplification (NASBA) assay were evaluated on cervical and vaginal samples from females and on urethral and first voided urine samples from males. As reference methods, the Cobas Amplicor PCR, as the main 'gold standard' method, and LightMix 480HT PCR were used. Results The overall prevalence of C. trachomatis infection was 12.6%. The Russian NAATs and the reference methods displayed a high level of concordance (97.9% to 99.2%). In comparison with the reference methods, the sensitivities, specificities, positive predictive values and negative predictive values of the Russian tests in different specimens ranged from 86.1% to 100%, 99.1% to 100%, 92.3% to 100% and 98.2% to 100%, respectively. Conclusions According to the reference methods, C. trachomatis NAATs developed and used in Russia have relatively good performance characteristics for both invasive and non-invasive samples. However, larger studies that include symptomatic and asymptomatic patients as well as genital and extra-genital samples, and in comparison with other internationally well-recognized, validated, and ideally Food and Drug Administration-approved C. trachomatis NAATs performed strictly according to the manufacturer's instructions, need to be conducted. Conflicts of interest None declared.
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| 35. |
- Shipitsyna, Elena, et al.
(författare)
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Pooling samples : the key to sensitive, specific and cost-effective genetic diagnosis of Chlamydia trachomatis in low-resource countries
- 2007
-
Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 87:2, s. 140-143
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to compare the performance characteristics and cost-effectiveness of pooling endocervical samples for screening and diagnosis of Chlamydia trachomatis, and to investigate the prevalence of C. trachomatis infection in women in Leningrad Oblast, Russia. A total of 1500 endocervical samples were tested individually and when pooled in groups of 5 and 10 samples, respectively. A previously evaluated in-house diagnostic polymerase chain reaction (PCR) assay was utilized. The sensitivity and specificity of the PCR were not affected by either pooling strategy. The estimated prevalence of genital C. trachomatis infection was 6.6%, 6.1% and 6.0% based on individually tested samples, and pools of 5 and 10, respectively. For diagnosis of individual samples, the pooling strategies resulted in cost savings of 53.3% (5 samples per pool) and 44.0% (10 samples per pool). Pooling samples for PCR detection of C. trachomatis is an accurate and cost-saving approach for diagnosis and large-scale prevalence studies in St Petersburg, Russia.
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| 36. |
- Taha, Muhamed-Kheir, et al.
(författare)
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Defining the breakpoint for resistance to rifampicin in Neisseria meningitidis by rpoB sequencing
- 2009
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Clinical isolates of Neisseria meningitidis resistant to rifampicin are important to identify asthey lead to failure of chemoprophylaxis of meningococcal disease. However, theidentification of these isolates is hindered by the absence of a harmonized breakpoint despiteefforts of standardization. In the present study, a large number (n=352) of clinical N.meningitidis isolates from 12 mainly European countries and spanning over 25 years (1984 to2009) were examined. The collection comprised all clinical isolates with MIC 0.25 mg/lreceived by the national reference laboratories for meningococci in the participating countries(n=161). In addition, representative isolates displaying MIC of rifampicin <0.25 mg/l wereexamined (n=191). Phenotyping and genotyping of isolates were performed and a 660 bpDNA fragment of the rpoB gene was sequenced in all the included isolates. Sequencesdiffering by at least one nucleotide were defined as a unique rpoB allele (n=55). Geometricmeans of MIC were calculated for isolates displaying the same allele. All the clinical isolatesdisplaying MIC >1 mg/l of rifampicin possessed rpoB alleles with critical mutations (in total21 alleles), resulting in substitutions at the codon H552 and less frequently at nearby codons(S548 and S557). These alterations were absent in the alleles (n=34) found in all isolates withMIC 1 mg/l. Based on these findings, rifampicin susceptible isolates could be defined asthose with MIC 1 mg/l. A new web site was created based on the data from this work (http://neisseria.org/nm/typing/rpoB). The rifampicin resistant isolates belonged to diversegenetic lineages and provoked lower bacteremia levels in mice. This biological cost mayexplain the non-expansion of the rifampicin resistant isolates.
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| 37. |
- Thulin Hedberg, Sara
(författare)
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Antibiotic susceptibility and resistance in Neisseria meningitidis : phenotypic and genotypic characteristics
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neisseria meningitidis, also known as the meningococcus, is a globally spread obligate human bacterium causing meningitis and/or septicaemia. It is responsible for epidemics in both developed and developing countries. Untreated invasive meningococcal disease is often fatal, and despite modern intensive care units, the mortality is still remarkably high (approximately 10%). The continuously increasing antibiotic resistance in many bacterial pathogens is a serious public health threat worldwide and there have been numerous reports of emerging resistance in meningococci during the past decades. In paper I, the gene linked to reduced susceptibility to penicillins, the penA gene, was examined. The totally reported variation in all published penA genes was described. The penA gene was highly variable (in total 130 variants were identified). By examination of clinical meningococcal isolates, the association between penA gene sequences and penicillin susceptibility could be determined. Isolates with reduced susceptibility displayed mosaic structures in the penA gene. Two closely positioned nucleotide polymorphisms were identified in all isolates with reduced penicillin susceptibility and mosaic structured penA genes. These alterations were absent in all susceptible isolates and were successfully used to detect reduced penicillin susceptibility by real-time PCR and pyrosequencing in paper II. In papers III and IV, antibiotic susceptibility and characteristics of Swedish and African meningitis belt meningococcal isolates were comprehensively described. Although both populations were mainly susceptible to the antibiotics used for treatment and prophylaxis, the proportion of meningococci with reduced penicillin susceptibility was slightly higher in Sweden. A large proportion of the African isolates was resistant to tetracycline and erythromycin. In paper V, the gene linked to rifampicin resistance, the rpoB gene, was examined in meningococci from 12 mainly European countries. Alterations of three amino acids in the RpoB protein were found to always and directly lead to rifampicin resistance. A new breakpoint for rifampicin resistance in meningococci was suggested. The biological cost of the RpoB alterations was investigated in mice. The pathogenicity/virulence was significantly lower in rifampicin resistant mutants as compared with susceptible wild-type bacteria.
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| 38. |
- Thulin, Sara, et al.
(författare)
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Total variation in the penA gene of Neisseria meningitidis : correlation between susceptibility to beta-lactam antibiotics and penA gene heterogeneity
- 2006
-
Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 50:10, s. 3317-3324
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Tidskriftsartikel (refereegranskat)abstract
- In recent decades, the prevalence of Neisseria meningitidis isolates with reduced susceptibility to penicillins has increased. The intermediate resistance to penicillin (Pen(i)) for most strains is due mainly to mosaic structures in the penA gene, encoding penicillin-binding protein 2. In this study, susceptibility to beta-lactam antibiotics was determined for 60 Swedish clinical N. meningitidis isolates and 19 reference strains. The penA gene was sequenced and compared to 237 penA sequences from GenBank in order to explore the total identified variation of penA. The divergent mosaic alleles differed by 3% to 24% compared to those of the designated wild-type penA gene. By studying the final 1,143 to 1,149 bp of penA in a sequence alignment, 130 sequence variants were identified. In a 402-bp alignment of the most variable regions, 84 variants were recognized. Good correlation between elevated MICs and the presence of penA mosaic structures was found especially for penicillin G and ampicillin. The Pen(i) isolates comprised an MIC of >0.094 microg/ml for penicillin G and an MIC of >0.064 microg/ml for ampicillin. Ampicillin was the best antibiotic for precise categorization as Pen(s) or Pen(i). In comparison with the wild-type penA sequence, two specific Pen(i) sites were altered in all except two mosaic penA sequences, which were published in GenBank and no MICs of the corresponding isolates were described. In conclusion, monitoring the relationship between penA sequences and MICs to penicillins is crucial for developing fast and objective methods for susceptibility determination. By studying the penA gene, genotypical determination of susceptibility in culture-negative cases can also be accomplished.
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| 39. |
- Unemo, Magnus, 1970-, et al.
(författare)
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Genetic homogeneity/heterogeneity of Propionibacterium acnes isolated from patients during cardiothoracic reoperation
- 2007
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Ingår i: Anaerobe. - London : Academic Press. - 1075-9964 .- 1095-8274. ; 13:3-4, s. 121-126
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Tidskriftsartikel (refereegranskat)abstract
- Following cardiothoracic surgery, deep sternal wound infection (SWI) remains one of the most severe complications. Recently, Propionibacterium acnes has been suspected as an etiological agent of deep SWI. However, this bacterium constitutes part of the resident micro-flora of the human skin. Consequently, findings of P. acnes in invasive samples are difficult to value. The aims of this study were to develop and optimize a pulsed-field gel electrophoresis (PFGE) protocol for P. acnes, in order to investigate the genetic homogeneity/heterogeneity of P. acnes isolates from multiple tissue samples (predominantly biopsies), collected at different locations, from 12 patients during cardiothoracic reoperation. There were 24 distinguishable PFGE fingerprints identified among the P. acnes isolates (n=54). Five (42%) of the patients carried only isolates that were interpreted as presumably clonally related. From the remaining seven patients, two or three different P. acnes clones were cultured, however, from six of them, the clones were identified in multiple samples. P. acnes may be a relatively frequent etiological agent of postoperative cardiothoracic infections. Existence of several clonally related P. acnes isolates derived from multiple samples from patients suffering from deep SWI after cardiothoracic surgery has not previously been shown.
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| 40. |
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| 41. |
- Unemo, Magnus, et al.
(författare)
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Molecular characterization of Neisseria gonorrhoeae identifies transmission and resistance of one ciprofloxacin-resistant strain
- 2007
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 115:3, s. 231-240
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Tidskriftsartikel (refereegranskat)abstract
- A highly discriminative and objective genetic characterization of N. gonorrhoeae, which increases our knowledge of strain populations in different geographic areas, is crucial for the development of improved control measures. In the present study, conventional phenotypic characterization and genetic characterization by means of pulsed-field gel electrophoresis (PFGE), sequencing of the entire porB gene, N. gonorrhoeae multiantigen sequence typing (NG-MAST), and pyrosequencing of a quinolone resistance determining region (QRDR) of the gyrA gene of Swedish ciprofloxacin-resistant N. gonorrhoeae serovar IB-10 isolates (n=45) were performed. The genetic characterization identified one widely spread ciprofloxacin-resistant N. gonorrhoeae ST147 strain. In addition, isolates with slightly different genetic characteristics, which presumably reflect the ongoing evolution only, were also identified. All the isolates contained single nucleotide polymorphisms in QRDR of the gyrA gene that are highly correlated with ciprofloxacin resistance. Consequently, comprehensive characterization identified the first confirmed large domestic transmission, mainly among young heterosexuals, of one ciprofloxacin-resistant N. gonorrhoeae strain in Swedish society during 2002-2003. In conclusion, a precise, i. e. genetic, characterization for identification of individual strains is a very valuable support to the crucial active surveillance of the epidemiological characteristics and the antibiotic susceptibility of N. gonorrhoeae in the effective treatment of gonorrhoea.
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| 42. |
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| 43. |
- Unemo, Magnus, 1970-, et al.
(författare)
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The por A pseudogene of Neisseria gonorrhoeae - low level of genetic polymorphism and a few, mainly identical, inactivating mutations.
- 2005
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 113:6, s. 410-419
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Tidskriftsartikel (refereegranskat)abstract
- N. meningitidis is the only Neisseria species known to express two outer membrane porins, PorA and PorB. However, a porA pseudogene has been identified in N. gonorrhoeae. The present study investigated the prevalence and genetic polymorphism of this porA pseudogene in 87 different N. gonorrhoeae strains. The porA pseudogene was identified in all isolates. The pseudogene comprised 12 (5.5%), of which 10 were located in the promoter spacer, and 11 (1.0%) polymorphic nucleotide sites in the upstream segment containing the promoter region, i.e. the putative -10 and -35 sequences and the promoter spacer in-between, and the hypothetical PorA coding sequence, respectively. A phylogenetic analysis of the upstream segment and the hypothetical coding sequence identified 36 sequence variants, of which 30 were not previously described. All strains comprised at least two identical confirmed inactivating deletions, of which one was located in the promoter region and one in the hypothetical PorA coding sequence. In conclusion, the porA pseudogene and its few inactivating mutations are widespread in the N. gonorrhoeae population and the homology with the N. meningitidis porA gene reflects their common evolutionary origin. The highly conserved N. gonorrhoeae porA pseudogene may reflect an evolutionary neutral molecular clock and may be a suitable genetic target for diagnosis of N. gonorrhoeae.
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| 44. |
- Unemo, Magnus, et al.
(författare)
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The sialic acid binding SabA adhesin of Helicobacter pylori is essential for nonopsonic activation of human neutrophils.
- 2005
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Ingår i: The Journal of biological chemistry. - 0021-9258 .- 1083-351X. ; 280:15, s. 15390-7
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Tidskriftsartikel (refereegranskat)abstract
- Infiltration of neutrophils and monocytes into the gastric mucosa is a hallmark of chronic gastritis caused by Helicobacter pylori. Certain H. pylori strains nonopsonized stimulate neutrophils to production of reactive oxygen species causing oxidative damage of the gastric epithelium. Here, the contribution of some H. pylori virulence factors, the blood group antigen-binding adhesin BabA, the sialic acid-binding adhesin SabA, the neutrophil-activating protein HP-NAP, and the vacuolating cytotoxin VacA, to the activation of human neutrophils in terms of adherence, phagocytosis, and oxidative burst was investigated. Neutrophils were challenged with wild type bacteria and isogenic mutants lacking BabA, SabA, HP-NAP, or VacA. Mutant and wild type strains lacking SabA had no neutrophil-activating capacity, demonstrating that binding of H. pylori to sialylated neutrophil receptors plays a pivotal initial role in the adherence and phagocytosis of the bacteria and the induction of the oxidative burst. The link between receptor binding and oxidative burst involves a G-protein-linked signaling pathway and downstream activation of phosphatidylinositol 3-kinase as shown by experiments using signal transduction inhibitors. Collectively our data suggest that the sialic acid-binding SabA adhesin is a prerequisite for the nonopsonic activation of human neutrophils and, thus, is a virulence factor important for the pathogenesis of H. pylori infection.
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| 45. |
- Vagoras, A., et al.
(författare)
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Diagnosis of non-viral sexually transmitted infections in Lithuania and international recommendations
- 2006
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Ingår i: Eurosurveillance. - : European Centre for Disease Control and Prevention (ECDC). - 1025-496X .- 1560-7917. ; 11:7, s. 161-164
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to evaluate the range, quality and availability of diagnostic services for non-viral sexually transmitted infections (STIs), i.e. C. trachomatis, N. gonorrhoeae, T. vaginalis and T. pallidum, in Lithuania from September 2002 to December 2003. Surveillance data describing the organisation and performance characteristics of non-viral STI diagnostic services in Lithuania were collected using a questionnaire and subsequent site-visits. International evidence-based recommendations for non-viral STI diagnosis were used to evaluate the quality of the STI diagnostics. There were 171 facilities providing non-viral STI diagnostic services for the 3.5 million inhabitants of Lithuania. However, only 6% (n=9) of the respondents (n=153) could provide a confirmatory diagnosis, in accordance with international recommendations, for the full minimum range of relevant non-viral STIs in Lithuania, i.e. C. trachomatis, N. gonorrhoeae, T. pallidum, and T. vaginalis. In addition, accessibility to STI diagnostic services differed significantly among the different counties in Lithuania. Several of the respondents analysed low numbers of samples each year, and overall the sampling size was extremely low, especially for C. trachomatis diagnostics. In Lithuania, optimisation of non-viral STI diagnostics as well as of epidemiological surveillance and management of STIs is crucial. It may be worth considering a decrease in the number of laboratories, with those remaining having the possibility of performing STI diagnostic services that are optimised, in concordance with international recommendations, standardised, and quality assured using systematic internal and external quality controls and systems. In addition, establishment of national inter-laboratory networks and reference centres for non-viral STIs is recommended.
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| 46. |
- Åkerlund, Thomas, et al.
(författare)
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Increased sporulation rate of epidemic Clostridium difficile Type 027/NAP1
- 2008
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 46:4, s. 1530-1533
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Tidskriftsartikel (refereegranskat)abstract
- Clostridium difficile PCR ribotype 027 comprised 0.2% of a collection of Swedish isolates in 1997-2001 (3 of 1,325 isolates). These isolates had lower moxifloxacin MICs than the epidemic type 027 isolates, but they had the same tcdC sequence and toxin yield. Type 027 produced 3- to 13-fold more toxin than did major Swedish types. One epidemic strain (027/NAP1a) sporulated more than did other type 027 isolates, a feature that should contribute to its survival and spread.
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