| 1. |
- Ahrén, C M, et al.
(författare)
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Comparison of methods for detection of colonization factor antigens on enterotoxigenic Escherichia coli.
- 1986
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 23:3, s. 586-91
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Tidskriftsartikel (refereegranskat)abstract
- Fecal Escherichia coli isolates from 196 patients with watery diarrhea and 68 healthy individuals (controls) were analyzed in Bangladesh immediately after isolation for the presence of colonization factor antigen (CFA) I or II (CFA/I or CFA/II, respectively) by a mannose-resistant hemagglutination (MRHA) test with six species of erythrocytes and by a slide agglutination test with absorbed CFA/I or CFA/II antisera. The presence of CFAs was confirmed by immunodiffusion analyses done in Sweden. By these methods, it was found that 49 of 69 enterotoxin-producing E. coli strains isolated from patients carried CFA/I or CFA/II, whereas none of the nonenterotoxigenic E. coli isolates or the three toxin-positive strains isolated from healthy individuals carried these adhesins. All E. coli strains retained their MRHA ability after transportation to Sweden followed by one subculture and after storage at -70 degrees C (but not at room temperature) for 1 to 2 years without further subculturing. After 5 to 10 subcultures of the fresh isolates, however, 70% of the initially CFA/I- and 80% of the initially CFA/II-carrying strains analyzed did not hemagglutinate. The efficacy of different methods for detecting CFAs on the fresh isolates was compared with that of immunodiffusion. The sensitivity of MRHA with human blood group A erythrocytes for the detection of CFA/I was high (97%), but the specificity was only 69%. The sensitivity of MRHA with bovine erythrocytes for the detection of CFA/II in Bangladesh was very low but increased considerably when chicken erythrocytes were also used. Whereas both false-positive and false-negative reactions were obtained when absorbed CFA antisera were used for agglutination, antisera against purified CFAs were equally effective as immunodiffusion in identifying CFA/I and CFA/II-carrying strains.
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| 2. |
- Albert, MJ, et al.
(författare)
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Rapid detection of Vibrio cholerae O139 Bengal from stool specimens by PCR
- 1997
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Ingår i: Journal of clinical microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 35:6, s. 1633-1635
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study using pure bacterial cultures in a PCR assay, a primer pair corresponding to a unique chromosomal region of Vibrio cholerae O139 Bengal generated an amplicon from only V. cholerae O139 Bengal. PCR with the same primer pair was used to screen 180 diarrheal stool specimens. All the 67 V. cholerae O139 culture-positive stool specimens were positive by PCR, and the remaining specimens, which contained either other recognized enteric pathogens or no pathogens, were all negative by PCR.
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| 3. |
- Alexeyev, Oleg A, et al.
(författare)
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Direct visualization of Propionibacterium acnes in prostate tissue by multicolor fluorescent in situ hybridization assay.
- 2007
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 45:11, s. 3721-8
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Tidskriftsartikel (refereegranskat)abstract
- Prostate tissues from patients with prostate cancer and benign prostatic hyperplasia (BPH) frequently contain histological inflammation, and a proportion of these patients show evidence of Propionibacterium acnes infection in the prostate gland. We developed a multicolor fluorescent in situ hybridization (FISH) assay targeting P. acnes 23S rRNA along with a 14-kb region of the P. acnes genome. This assay was used to analyze prostate tissues from patients with prostate cancer and BPH. P. acnes infection of the prostate gland was demonstrated in prostatic tissue in 5 of 10 randomly selected prostate cancer patients. FISH analysis and confocal laser microscopy imaging revealed intracellular localization and stromal biofilm-like aggregates as common forms of P. acnes infection in prostate tissues from both prostate cancer and BPH patients. A sequential analysis of prostate tissue from individual patients suggested that P. acnes can persist for up to 6 years in the prostate gland. These results indicate that P. acnes can establish a persistent infection in the prostate gland. Further study is needed to clarify the link between this bacterium and prostatic inflammation which may contribute to the development of BPH and prostate cancer.
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| 4. |
- Allard, A, et al.
(författare)
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Rapid typing of human adenoviruses by a general PCR combined with restriction endonuclease analysis.
- 2001
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 39:2, s. 498-505
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a system for rapid typing of adenoviruses (Ads) based on a combination of PCR and restriction endonuclease (RE) digestion (PCR-RE digestion). Degenerated consensus primers were designed, allowing amplification of DNA from all 51 human Ad prototype strains and altogether 44 different genome variants of Ad serotypes 1, 3, 4, 5, 7, 11, 19, 40, and 41. The 301-bp amplimer of 22 prototype strains representing all six subgenera and the genome variant was selected as a target for sequencing to look for subgenus and genome type variabilities. The sequences obtained were used to facilitate the selection of specific REs for discrimination purposes in a diagnostic assay by following the concept of cleavage or noncleavage of the 301-bp amplimer. On the basis of these results, a flowchart was constructed, allowing identification of subgenus B:2 and D serotypes and almost complete distinction of subgenus A, B:1, C, E, and F serotypes. Application of the PCR-RE digestion system to clinical samples allowed typing of 34 of 40 clinical samples positive for Ad. The genome type determined by this method was identical to that obtained by traditional RE typing of full-length Ad DNA. The remaining six samples were positive only after a nested PCR. Therefore, to reduce the risk of false-negative results, samples scored negative by the PCR-RE digestion system should be evaluated by the described nested PCR. Used in combination, the PCR-RE digestion method and the nested PCR provide a reliable and sensitive system that can easily be applied to all kinds of clinical samples when rapid identification of adenoviruses is needed.
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| 5. |
- Aspevall, O, et al.
(författare)
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Performance of four chromogenic urine culture media after one or two days of incubation compared with reference media.
- 2002
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 40, s. 1500-1503
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Tidskriftsartikel (refereegranskat)abstract
- Four chromogenic urine culture media were compared to culture on blood agar, MacConkey agar, and CLED (cysteine-, lactose-, and electrolyte-deficient) agar for detection of uropathogens in 1,200 urine specimens. After 2 nights of incubation, 96% of all isolates were recovered on blood agar, 96% were recovered on CLED agar, 92% were recovered on CPS ID2, 96% were recovered on CHROMagar Orientation from BBL, 95% were recovered on CHROMagar Orientation from The CHROMagar Company, and 95% were recovered on Chromogenic UTI Medium.
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| 6. |
- Ayukekbong, James, et al.
(författare)
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Pattern of Circulation of Norovirus GII Strains during Natural Infection
- 2014
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 52:12, s. 4253-4259
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Tidskriftsartikel (refereegranskat)abstract
- Norovirus (NoV) is considered a major cause of nonbacterial gastroenteritis among people of all ages worldwide, but the natural course of infection is incompletely known. In this study, the pattern of circulation of NoVs was studied among 146 children and 137 adults in a small community in southwestern Cameroon. The participants provided monthly fecal samples during a year. NoV RNA was detected in at least one sample from 82 (29%) of the participants. The partial VP1 region could be sequenced in 36 NoV GII-positive samples. Three different genotypes were identified (GII.1, GII.4, and GII.17), with each genotype circulating within 2 to 3 months and reappearing after a relapse period of 2 to 3 months. Most infections occurred once, and 2 episodes at most within a year were detected. No difference in the frequency of NoV infection between children and adults was recorded. The same genotype was detected for a maximum of 2 consecutive months in 3 children only, suggesting that a less than 30-day duration of viral shedding in natural infection was common. Reinfection within a year with the same genotype was not observed, consistent with short-term homotypic immune protection. The study revealed that NoV strains are circulating with a limited duration of viral shedding both in the individuals and the population as part of their natural infection. The results also provide evidence of cross-protective immunity of limited duration between genotypes of the same genogroup.
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| 7. |
- Belak, Sandor
(författare)
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Rapid PCR-Based Molecular Pathotyping of H5 and H7 Avian Influenza Viruses
- 2011
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 49, s. 3860-3873
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Tidskriftsartikel (refereegranskat)abstract
- While the majority of avian influenza virus (AIV) subtypes are classified as low-pathogenicity avian influenza viruses (LPAIV), the H5 and H7 subtypes have the ability to mutate to highly pathogenic avian influenza viruses (HPAIV) in poultry and therefore are the etiological agents of notifiable AIV (NAIV). It is of great importance to distinguish HPAIV from LPAIV variants during H5/H7 outbreaks and surveillance. To this end, a novel and fast strategy for the molecular pathotyping of H5/H7 AIVs is presented. The differentiation of the characteristic hemagglutinin (HA) protein cleavage sites (CSs) of HPAIVs and LPAIVs is achieved by a novel PCR method where the samples are interrogated for all existing CSs with a 484-plex primer mixture directly targeting the CS region. CSs characteristic for HP or LP H5/H7 viruses are distinguished in a seminested duplex real-time PCR format using plexor fluorogenic primers. Eighty-six laboratory isolates and 60 characterized NAIV-positive clinical specimens from poultry infected with H5/H7 both experimentally and in the field were successfully pathotyped in the validation. The method has the potential to substitute CS sequencing in the HA gene for the determination of the molecular pathotype, thereby providing a rapid means to acquire additional information concerning NAIV outbreaks, which may be critical to their management. The new assay may be extended to the LP/HP differentiation of previously unknown H5/H7 isolates. It may be considered for integration into surveillance and control programs in both domestic and wild bird populations.
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| 8. |
- Belak, Sandor
(författare)
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Real-Time PCR-Based Pathotyping of Newcastle Disease Virus by Use of TaqMan Minor Groove Binder Probes
- 2009
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 47, s. 2114-2123
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Tidskriftsartikel (refereegranskat)abstract
- A real-time reverse-transcription PCR was developed to detect and pathotype Newcastle disease viruses (NDV) in clinical samples. Degenerate oligonucleotide primers and TaqMan probes with nonfluorescent minor groove binder (MGB) quencher amplified and hybridized to a region in the fusion protein (F) gene that corresponds to the cleavage site of the F0 precursor, which is a key determinant of NDV pathogenicity. The application of degenerate primers and TaqMan MGB probes provided high specificity to the assay, as was shown by the successful and rapid pathotype determination of 39 NDV strains representing all the known genotypes (I to VIII) and pathotypes (lentogens/mesogens/velogens). The PCR assays specific for lentogenic and velogenic/mesogenic strains had high analytical sensitivity, detecting approximately 10 and 20 copies of the target molecule per reaction, respectively. The detection limit was also determined in terms of 50% egg infective dose (EID(50)) by using dilution series of virus stock solutions to be approximately 10(1.0) and 10(-1.3) EID(50)/ml for lentogens and velogens/mesogens, respectively. Organ, swab, and stool specimens from experimentally infected animals were tested to prove the clinical suitability of the method. The results of this study suggest that the described real-time PCR assay has the potential to be used for the rapid detection/pathotyping of NDV isolates and qualitative/quantitative measurement of the virus load.
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| 9. |
- Bergqvist, Cecilia, et al.
(författare)
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Multiplex Nucleic Acid Suspension Bead Arrays for Detection and Subtyping of Filoviruses
- 2015
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 53:4, s. 1368-1370
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Tidskriftsartikel (refereegranskat)abstract
- Here we describe multiplex suspension bead array systems that allow fast and reliable detection of reverse transcriptase (RT) PCR amplified filovirus genomes and also enable subtyping of Ebola virus species and Marburg virus strains. These systems have an analytical sensitivity equivalent to that of RT-PCR.
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| 10. |
- Blomström, Anne-Lie, et al.
(författare)
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Detection of a Novel Astrovirus in Brain Tissue of Mink Suffering from Shaking Mink Syndrome by Use of Viral Metagenomics
- 2010
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 48, s. 4392-4396
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Tidskriftsartikel (refereegranskat)abstract
- In 2000, farmed mink kits in Denmark were affected by a neurological disorder. The characteristic clinical signs included shaking, staggering gait, and ataxia. The disease, given the name shaking mink syndrome, was reproduced by the inoculation of brain homogenate from affected mink kits into healthy ones. However, the etiology remained unknown despite intensive efforts. In this study, random amplification and large-scale sequencing were used, and an astrovirus was detected in the brain tissue of three experimentally infected mink kits. This virus also was found in the brain of three mink kits naturally displaying the disease but not in the six healthy animals investigated. The complete coding region of the detected astrovirus was sequenced and compared to those of both a mink astrovirus associated with preweaning diarrhea and to a recently discovered human astrovirus associated with a case of encephalitis in a boy with x-linked agammaglobulinemia. The identities were 80.4 and 52.3%, respectively, showing that the virus described in this study was more similar to the preweaning diarrhea mink astrovirus. For the nonstructural coding regions the sequence identity was around 90% compared to that of the astrovirus, which is associated with preweaning diarrhea in mink. The region coding for the structural protein was more diverse, showing only 67% sequence identity. This finding is of interest not only because the detected virus may be the etiological agent of the shaking mink syndrome but also because this is one of the first descriptions of an astrovirus found in the central nervous system of animals.
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| 11. |
- Bom, Reinier J. M., et al.
(författare)
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Evaluation of High-Resolution Typing Methods for Chlamydia trachomatis in Samples from Heterosexual Couples
- 2011
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 49:8, s. 2844-2853
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to compare conventional ompA typing of Chlamydia trachomatis with multilocus sequence typing (MLST) and multilocus variable-number tandem-repeat (VNTR) analysis (MLVA). Previously used MLST and MLVA systems were compared to modified versions that used shorter target regions and nested PCR. Heterosexual couples were selected from among persons with urogenital C. trachomatis infections visiting the sexually transmitted infection outpatient clinic in Amsterdam, The Netherlands. We identified 30 couples with a total of 65 degrees C. trachomatis-positive samples on which MLST and MLVA for eight target regions were performed. All regions were successfully sequenced in 52 samples, resulting in a complete profile for 18 couples and 12 individuals. Nine ompA genovars from D to K, with two variants of genovar G, were found. The numbers of sequence type and MLVA type profiles were 20 for MLST and 21 for MLVA, and a combination of MLST and MLVA yielded 28 profiles, with discriminatory indexes (D) ranging from 0.95 to 0.99. Partners in 17 couples shared identical profiles, while partners in 1 couple had completely different profiles. Three persons had infections at multiple anatomical locations, and within each of these three individuals, all profiles were identical. The discriminatory capacity of all MLST and MLVA methods is much higher than that of ompA genotyping (D = 0.78). No genotype variation was found within the samples of the same person or from heterosexual couples with a putative single transmission. This shows that the chlamydial genome in clinical specimens has an appropriate polymorphism to enable epidemiological cluster analysis using MLST and MLVA.
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| 12. |
- Boman, Jens, 1957-, et al.
(författare)
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Failure to detect Chlamydia trachomatis in cell culture by using a monoclonal antibody directed against the major outer membrane protein
- 1997
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 35:10, s. 2679-2680
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Tidskriftsartikel (refereegranskat)abstract
- Two commercially available monoclonal antibodies for cell culture confirmation of Chlamydia trachomatis were compared in two prospective studies and one large retrospective study. In total, more than 33,000 genital specimens were cultured in parallel and stained with both antibodies, one of which was directed against the major outer membrane protein (MOMP) and one uf which was directed against the lipopolysaccharide (LPS). We found the anti-LPS-based assay to be more sensitive and as specific as the anti-MOMP-based assay for C. trachomatis cell culture confirmation of genital specimens.
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| 13. |
- Bongcam Rudloff, Erik, et al.
(författare)
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Molecular Typing of Escherichia coli O157:H7 Isolates from Swedish Cattle and Human Cases: Population Dynamics and Virulence
- 2014
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 52, s. 3906-3912
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Tidskriftsartikel (refereegranskat)abstract
- While all verotoxin-producing Escherichia coli O157:H7 bacteria are considered potential pathogens, their genetic subtypes appear to differ in their levels of virulence. The aim of this study was to compare the distribution of subtypes of E. coli O157:H7 in the cattle reservoir and in human cases with and without severe complications in order to gain clues about the relationship between subtype and relative virulence. A lineage-specific polymorphism assay (LSPA-6), multilocus variable-number tandem-repeat analysis (MLVA), and a novel real-time PCR assay to identify clade 8 were applied to a large and representative set of isolates from cattle from 1996 to 2009 (n = 381) and human cases from 2008 to 2011 (n = 197) in Sweden. Draft genome sequences were produced for four selected isolates. The E. coli O157:H7 isolates in Swedish cattle generally belonged to four groups with the LSPA-6 profiles 211111 (clade 8/non-clade 8), 213111, and 223323. The subtype composition of the cattle isolates changed dramatically during the study period with the introduction and rapid spread of the low-virulence 223323 subtype. The human cases presumed to have been infected within the country predominantly carried isolates with the profiles 211111 (clade 8) and 213111. Cases progressing to hemolytic-uremic syndrome (HUS) were mostly caused by clade 8, with MLVA profiles consistent with Swedish cattle as the source. In contrast, infections contracted abroad were caused by diverse subtypes, some of which were associated with a particular region. The work presented here confirms the high risk posed by the clade 8 variant of E. coli O157:H7. It also highlights the dynamic nature of the E. coli O157:H7 subtype composition in animal reservoirs and the importance of this composition for the human burden of disease.
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| 14. |
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| 15. |
- Broman, T., et al.
(författare)
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Campylobacter jejuni in black-headed gulls (Larus ridibundus) : prevalence, genotypes, and influence on C. jejuni epidemiology
- 2002
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 40:12, s. 4594-4602
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacteriosis is a zoonotic disease in which birds have been suggested to play an important role as a reservoir. We investigated the prevalence of Campylobacter jejuni subsp. jejuni in black-headed gulls (Larus ridibundus) in southern Sweden with the aim of examining the nature of C. jejuni infection in this bird species. Birds were sampled in four sampling series each year during 1999 (n = 419) and 2000 (n = 365). Longitudinally sampled C. jejuni isolates from individual gulls were subjected to macrorestriction profiling (MRP) by pulsed-field gel electrophoresis to investigate the genotypical stability during the natural course of infection. Furthermore, a subset (n = 76) of black-headed gull isolates was compared to isolates from broiler chickens (n = 38) and humans (n = 56) originating from the same geographic area. We found a pronounced seasonal variation in C. jejuni carriage, with the highest rates found in late autumn. MRP similarities were higher between isolates of human and broiler chicken origin, than between those of wild bird origin and either of the other two hosts. However, identical MRPs were found in two gull isolates and one human isolate after digestion with two restriction enzymes, strongly indicating that they may have been colonized by the same clone of C. jejuni. The MRPs most prevalent in gull isolates did not occur among isolates from humans and broiler chickens, suggesting the existence of a subpopulation of C. jejuni adapted to species-specific colonization or environmental survival.
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| 16. |
- Bucardo, F, et al.
(författare)
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Mutated G4P[8] rotavirus associated with a nationwide outbreak of gastroenteritis in Nicaragua in 2005
- 2007
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 45:3, s. 990-997
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Tidskriftsartikel (refereegranskat)abstract
- During February and March 2005, one of the largest national recorded outbreaks of severe acute gastroenteritis occurred in Nicaragua, affecting ≥64,000 individuals and causing ≥56 deaths, predominantly in children under 5 years of age. Through a nationwide laboratory-based study, stool samples were collected and investigated for rotavirus. Of 108 stool samples examined, 72 (67%) were positive for rotavirus. While 69% (50/72) of the positive samples were found in children less than 2 years of age, 50% (6/12) of the adult samples were positive. A mutated G4P[8] strain was the most commonly recognized strain (85%), followed by mixed G strains (8%) and G9P[8] (7%) strains. Phylogenetic analysis of the VP7 gene revealed that the G4 strains belonged to the emerging lineage Ic and was distantly related to the ST3 and VA70 G4 strains. Secondary structure predictions of the VP7 G4 protein revealed an insert of an asparagine residue in position 76, which, combined with additional mutations, surprisingly modified two downstream β-sheets at amino acid positions 80 to 85 and 115 to 119. The 2005 G4P[8] strain compared to a G4P[8] strain from 2002 had a substitution of an asparagine residue for threonine (Asn→Thr) at position 96 within antigenic region A, thus eliminating a potential glycosylation site. The mutated G4 virus was introduced in Nicaragua after 2002 and probably emerged from Brazil, Argentina, or Uruguay. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
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| 17. |
- Bucardo, Filemon, et al.
(författare)
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Pediatric norovirus diarrhea in Nicaragua
- 2008
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 46:8, s. 2573-2580
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Tidskriftsartikel (refereegranskat)abstract
- Information about norovirus (NoV) infections in Central America is limited. Through a passive community and hospital pediatric diarrhea surveillance program, a total of 542 stool samples were collected between March 2005 and February 2006 in León, Nicaragua. NoV was detected in 12% (65/542) of the children; of these, 11% (45/409) were in the community and 15% (20/133) were in the hospital, with most strains (88%) belonging to genogroup II. NoV infections were age and gender associated, with children of <2 years of age (P < 0.05) and girls (P < 0.05) being most affected. Breast-feeding did not reduce the number of NoV infections. An important proportion (57%) of NoV-infected children were coinfected with diarrheagenic Escherichia coli. A significant proportion (18/31) of NoV-positive children with dehydration required intravenous rehydration. Nucleotide sequence analysis (38/65) of the N-terminal and shell region in the capsid gene revealed that at least six genotypes (GI.4, GII.2, GII.4, GII.7, GII.17, and a potentially novel cluster termed "GII.18-Nica") circulated during the study period, with GII.4 virus being predominant (26/38). The majority (20/26) of those GII.4 strains shared high nucleotide homology (99%) with the globally emerging Hunter strain. The mean viral load was approximately 15-fold higher in children infected with GII.4 virus than in those infected with other G.II viruses, with the highest viral load observed for the group of children infected with GII.4 and requiring intravenous rehydration. This study, the first of its type from a Central American country, suggests that NoV is an important etiological agent of acute diarrhea among children of <2 years of age in Nicaragua.
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| 18. |
- Bunikis, J, et al.
(författare)
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Molecular polymorphism of the Lyme disease agent Borrelia garinii in northern Europe is influenced by a novel enzootic Borrelia focus in the North Atlantic
- 1996
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Ingår i: Journal of Clinical Microbiology. - Washington, DC, United States : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 34:2, s. 364-368
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Tidskriftsartikel (refereegranskat)abstract
- Lyme disease Borrelia species are distributed in temperate areas of North America and Eurasia. To elucidate the distribution of borreliae in subarctic regions, strains isolated from Ixodes ricinus and Ixodes uriae ticks found on islands in the northern Atlantic and Baltic Sea were molecularly characterized. All isolates were verified as Borrelia garinii by 16S rRNA gene analysis and immunoblotting with monoclonal antibodies specific for the outer surface proteins A and C. Three ribotypes (RTs) of B. garinii were delineated. I. ricinus complex-associated RT1 was phenotypically most heterogeneous. Two newly identified ribotypes were shared by different tick species and conformed to two established OspA serotypes. RT2 was restricted to the islands in the northern Baltic Sea, whereas RT3 was recovered also from ticks found in the North Atlantic. In conclusion, molecular polymorphism of the studied borrelia isolates suggests a complex enzootic potential of B. garinii in northern Europe and implies a novel, seabird tick I. uriae-associated enzootic focus of Lyme disease borreliae in the North Atlantic.
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| 19. |
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| 20. |
- Christerson, Linus, et al.
(författare)
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Chlamydia trachomatis Strains Show Specific Clustering for Men Who Have Sex with Men Compared to Heterosexual Populations in Sweden, the Netherlands, and the United States
- 2012
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 50:11, s. 3548-3555
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution genotyping of Chlamydia trachomatis improves the characterization of strains infecting different patient groups and sexual networks. In this study, multilocus sequence typing (MLST) and ompA sequence determination were used for an analysis of C. trachomatis strains from 203 men who have sex with men (MSM) from Sweden, the Netherlands, and the United States. The results obtained were compared with data from 153 heterosexual women from Sweden and the Netherlands. The overlap in MLST/ompA profiles between MSM from Sweden and the Netherlands was 68%, while the overlap between heterosexual populations from these countries was only 18%. The distribution of genotypes in MSM from the United States was less similar to that in MSM from the European countries, with 45% and 46% overlaps for MSM in Sweden and the Netherlands, respectively. Minimum-spanning-tree analysis of MLST/ompA sequence types identified two large clusters that contained almost exclusively samples from MSM and comprised 74% of all MSM samples. Three other clusters were predominated by samples from women but also contained MSM specimens. Of 19 detected variants of the MLST target CT144, three variants were highly associated with MSM. Our study supports the hypotheses of both tissue tropism as well as epidemiological network structures as explanations for the linkage between specific genetic variants and sexual orientation.
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| 21. |
- Christerson, Linus, 1985-, et al.
(författare)
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High-Resolution Genotyping of Chlamydia trachomatis by Use of a Novel Multilocus Typing DNA Microarray
- 2011
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 49:8, s. 2838-2843
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Tidskriftsartikel (refereegranskat)abstract
- Typing of Chlamydia trachomatis is important to understandingits epidemiology. Currently used methods such as DNA sequencingof the ompA gene and multilocus sequence typing (MLST) eitheroffer limited epidemiological resolution or are laborious andexpensive, or both. DNA microarray technology using the ArrayStripformat is an affordable alternative for genotyping. In thisstudy, we developed a new multilocus typing (MLT) DNA microarray,based on the target regions of a high-resolution MLST systemas well as software for easy analysis. Validation of the arraywas done by typing 80 previously MLST-typed clinical specimensfrom unselected adolescents in school. The MLT array showed100% specificity and provided 2.4-times-higher resolution thanompA sequencing, separating the commonly predominating ompAE/Bour genotype into 7 MLT array genotypes. The MLT array reproducedepidemiological findings revealed by the MLST system and showedsufficient sensitivity to work with clinical specimens. Comparedto MLST analysis, the expenses needed for testing a sample withthe MLT array are considerably lower. Moreover, testing canbe completed within 1 working day rather than 3 or 4 days, withdata analysis not requiring highly specialized personnel. Thepresent MLT array represents a powerful alternative in C. trachomatisgenotyping.
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| 22. |
- Claesson, B A, et al.
(författare)
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Serum antibody response to capsular polysaccharide, outer membrane, and lipooligosaccharide in children with invasive Haemophilus influenzae type b infections.
- 1987
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 25:12, s. 2339-43
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Tidskriftsartikel (refereegranskat)abstract
- Serum antibodies against capsular polysaccharide (CPS), outer membrane (OM), and lipooligosaccharide (LOS) from Haemophilus influenzae type b were measured by enzyme-linked immunosorbent assay in acute- and convalescent-phase sera from 21 children between 3 months and 4 years of age with invasive H. influenzae type b infections. As expected, the levels of anti-CPS antibodies in the acute-phase serum samples were low or not detectable, as were the levels of antibodies against LOS. In contrast, all children had detectable antibodies against the OM in the acute-phase serum sample, indicating that they are of little or no importance for protection. An antibody response to CPS was noted in 13 of the 21 patients, mainly in the older children. An antibody response to the OM was seen in 16 patients, with no evident relation to age. The antibody response to the OM preparation, which consisted of proteins and LOS, was probably directed mainly against the OM proteins, since only six children showed a response, usually of low magnitude, of antibodies to LOS.
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| 23. |
- Demczuk, Walter, et al.
(författare)
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Genomic epidemiology and molecular resistance mechanisms of azithromycin resistant Neisseria gonorrhoeae in Canada from 1997 to 2014
- 2016
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Ingår i: Journal of Clinical Microbiology. - Washington, USA : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 54:5, s. 1304-1313
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Tidskriftsartikel (refereegranskat)abstract
- The emergence of Neisseria gonorrhoeae with decreased susceptibility to cephalosporins and azithromycin resistance (AZM-R) represent a public health threat of untreatable gonorrhoea infections. Genomic epidemiology through whole genome sequencing was used to describe the emergence, dissemination, and spread of AZM-R strains. The genomes of 213 AZM-R and 23 AZM-susceptible N. gonorrhoeae isolates collected in Canada from 1989 to 2014 were sequenced. Core single nucleotide polymorphism (SNP) phylogenomic analysis resolved 246 isolates into 13 lineages. High-level AZM-R (minimum inhibitory concentration ≥256 μg/ml) was found in 5 phylogenetically diverse isolates, all of which possessed the A2059G mutation (Escherichia coli numbering) in all four 23S rRNA alleles. One high-level AZM-R isolate collected in 2009 concurrently had decreased susceptibility to ceftriaxone (MIC=0.125 μg/ml). An increase in the number of 23S rRNA alleles with the C2611T mutations (E. coli numbering) conferred low to moderate AZM-R (2 to 4 and 8 to 32 μg/mL, respectively). Low level AZM-R was also associated with mtrR promoter mutations including -35A deletion and the presence of N. meningitidis-like sequences. Geographic and temporal phylogenetic clustering indicate emergent AZM-R strains arise independently and can then rapidly expand clonally in a region through local sexual networks.
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| 24. |
- Demczuk, Walter H.B., et al.
(författare)
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Neisseria gonorrhoeae Sequence Typing for Antimicrobial Resistance : a Novel Antimicrobial Resistance Multilocus Typing Scheme for Tracking Global Dissemination of N. gonorrhoeae Strains
- 2017
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 55:5, s. 1454-1468
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Tidskriftsartikel (refereegranskat)abstract
- A curated Web-based user-friendly sequence typing tool based on antimicrobial resistance determinants in Neisseria gonorrhoeae was developed and is publicly accessible (https://ngstar.canada.ca). The N. gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR) molecular typing scheme uses the DNA sequences of 7 genes (penA, mtrR, porB, ponA, gyrA, parC, and 23S rRNA) associated with resistance to β-lactam antimicrobials, macrolides, or fluoroquinolones. NG-STAR uses the entire penA sequence, combining the historical nomenclature for penA types I to XXXVIII with novel nucleotide sequence designations; the full mtrR sequence and a portion of its promoter region; portions of ponA, porB, gyrA, and parC; and 23S rRNA sequences. NG-STAR grouped 768 isolates into 139 sequence types (STs) (n = 660) consisting of 29 clonal complexes (CCs) having a maximum of a single-locus variation, and 76 NG-STAR STs (n = 109) were identified as unrelated singletons. NG-STAR had a high Simpson's diversity index value of 96.5% (95% confidence interval [CI] = 0.959 to 0.969). The most common STs were NG-STAR ST-90 (n = 100; 13.0%), ST-42 and ST-91 (n = 45; 5.9%), ST-64 (n = 44; 5.72%), and ST-139 (n = 42; 5.5%). Decreased susceptibility to azithromycin was associated with NG-STAR ST-58, ST-61, ST-64, ST-79, ST-91, and ST-139 (n = 156; 92.3%); decreased susceptibility to cephalosporins was associated with NG-STAR ST-90, ST-91, and ST-97 (n = 162; 94.2%); and ciprofloxacin resistance was associated with NG-STAR ST-26, ST-90, ST-91, ST-97, ST-150, and ST-158 (n = 196; 98.0%). All isolates of NG-STAR ST-42, ST-43, ST-63, ST-81, and ST-160 (n = 106) were susceptible to all four antimicrobials. The standardization of nomenclature associated with antimicrobial resistance determinants through an internationally available database will facilitate the monitoring of the global dissemination of antimicrobial-resistant N. gonorrhoeae strains.
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| 25. |
- Di Stefano, M, et al.
(författare)
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Reverse transcriptase sequence of paired isolates of cerebrospinal fluid and blood from patients infected with human immunodeficiency virus type 1 during zidovudine treatment
- 1995
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Ingår i: Journal of clinical microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 33:2, s. 352-5
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Tidskriftsartikel (refereegranskat)abstract
- Human immunodeficiency virus type 1 (HIV-1) isolates obtained from the blood of patients undergoing treatment with 3'-azido-3'-deoxythymidine (zidovudine [AZT]) show a decreased sensitivity to the drug in vitro. The aim of the present study was to determine if HIV-1 variants resistant to AZT are present also in the brain compartment. We selected sequential HIV-1 isolates from the blood and the cerebrospinal fluid (CSF) of six patients with HIV-1 infection undergoing AZT therapy for a time varying between 1 and 3 years. The isolates were used to infect peripheral blood mononuclear cell cultures which were used to prepare viral DNA. The viral DNA was amplified by PCR and then directly sequenced. Analysis of the reverse transcriptase (RT) sequence of the isolates from the CSF during therapy demonstrated that CSF-resistant isolates are characterized by the same mutations documented in resistant isolates from the blood compartment. Isolates obtained from one patient (patient 3) showed the same two mutations (codons 70 and 215) in blood and CSF, whereas isolates obtained from an additional four patients presented a different pattern of mutations in the two compartments. We also analyzed the degree of amino acid homology between RT sequences from blood and CSF isolates in patients before and during AZT treatment. The percentages of amino acid variations were approximately equal when isolates from the same or different compartments were considered. Excluding the codons involved in AZT resistance, the time point of sampling did not affect RT variations during therapy significantly. In conclusion, our studies show that AZT-resistant HIV-1 can be found in the CSF of patients undergoing treatment. The mutations linked to AZT resistance in the CSF isolates are the same as those identified in AZT-resistant isolates from blood.
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