| 1. |
- Helldal, Lisa, et al.
(author)
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Evaluation of MLVA for epidemiological typing and outbreak detection of ESBL-producing Escherichia coli in Sweden
- 2017
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In: Bmc Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 17
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Journal article (peer-reviewed)abstract
- Background: To identify the spread of nosocomial infections and halt outbreak development caused by Escherichia coli that carry multiple antibiotic resistance factors, such as extended-spectrum beta-lactamases (ESBLs) and carbapenemases, is becoming demanding challenges due to the rapid global increase and constant and increasing influx of these bacteria from the community to the hospital setting. Our aim was to assess a reliable and rapid typing protocol for ESBL-E. coli, with the primary focus to screen for possible clonal relatedness between isolates. All clinical ESBL-E. coli isolates, collected from hospitals (n = 63) and the community (n = 41), within a single geographical region over a 6 months period, were included, as well as clinical isolates from a polyclonal outbreak (ST131, n = 9, and ST1444, n = 3). The sporadic cases represented 36 STs, of which eight STs dominated i.e. ST131 (n = 33 isolates), ST648 (n = 10), ST38 (n = 9), ST12 and 69 (each n = 4), ST 167, 405 and 372 (each n = 3). The efficacy of multiple-locus variable number tandem repeat analysis (MLVA) was evaluated using three, seven or ten loci, in comparison with that of pulsed-field gel electrophoresis (PFGE) and multi locus sequence typing (MLST). Results: MLVA detected 39, 55 and 60 distinct types, respectively, using three (GECM-3), seven (GECM-7) or ten (GECM-10) loci. For GECM-7 and -10, 26 STs included one type and eleven STs each included several types, the corresponding numbers for GECM-3 were 29 and 8. The highest numbers were seen for ST131 (7,7 and 8 types, respectively), ST38 (5,5,8) and ST648 (4,5,5). Good concordance was observed with PFGE and GECM-7 and -10, despite fewer types being identified with MLVA; 78 as compared to 55 and 60 types. The lower discriminatory power of MLVA was primarily seen within the O25b-ST131 lineage (n = 34) and its H30-Rx subclone (n = 21). Epidemiologically unrelated O25b-ST131 isolates were clustered with O25b-ST131 outbreak isolates by MLVA, whereas the ST1444 outbreak isolates were accurately distinguished from unrelated isolates. Conclusion: MLVA, even when using only three loci, represents an easy initial typing tool for epidemiological screening of ESBL-E. coli. For the ST131-O25b linage, complementary methods may be needed to obtain sufficient resolution.
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| 2. |
- Helldal, Lisa, et al.
(author)
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Increasing prevalence of ESBL but not AmpC in Escherichia coli and Klebsiella pneumoniae, in Göteborg, 2004-2008
- 2009
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In: Scandinavian Society for Antimicrobial Chemotherapy - 2009, September 3, Tromsø, Norway.
-
Conference paper (other academic/artistic)abstract
- Introduction: The increasing prevalence of transferable broad-spectrum resistance to beta-lactams, such as Extended Spectrum Beta Lactamases (ESBL) and AmpC, is troublesome, since they confer resistance to cephalosporins and penicillins, and often also are associated with additional resistance. Materials and methods: Resistance for E. coli and Klebsiella pneumoniae isolated from urine (~10.000 isolates/year) and blood (~xxx isolates/year), during 2004-2008 were determined. Cephalosporin resistant isolates were examined for presence of ESBL with a double-disk-assay using clavulanic acid as inhibitory substance. Cefoxitine-resistant strains were analyzed for presence of AmpC with a second double-disk-assay using cloxacillin as inhibitory substance. Positive strains where further tested with PCR assays for ESBL and plasmid AmpC. Results: During 2004-2008 presence of ESBL increased from 0,3–1,5% in urinary and 0,0–1,4 % in blood E. coli. For Klebsiella the corresponding figures were 0,08–0,68% and 0%, respectively. For ESBL-producing E. coli, 60–80% were resistant also to quinolones and trimetoprime. In 2008, the vast a majority of the ESBL-isolates carried CTX-M subtype 1. Approximately 50 % is community-acquired isolates. 0,15-0,23% of the urinary E. coli-strains had phenotypical characteristics indicating AmpC-production. Presence of plasmid-mediated AmpC will be tested. Approximately 50% of these were multidrug resistant. In blood E coli isolates as well as in Klebsiella from urine and blood AmpC was rarely detected (0-2 isolates/year). Discussion and Conclusion: There is a steady increase in ESBL-producing bacteria in our region. However, the frequency of isolates with AmpC is still low. In addition, a majority of these strains are multidrug resistant which is particularly alarming.
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| 3. |
- Helldal, Lisa, et al.
(author)
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Shift of CTX-M genotypes has determined the increased prevalence of extended-spectrum beta-lactamase-producing Escherichia coli in south-western Sweden
- 2013
-
In: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 19:2
-
Journal article (peer-reviewed)abstract
- The prevalence of Escherichia coli producing extended-spectrum β-lactamases (ESBLs) markedly increased during 2004-2008 in south-western Sweden, with a greater increase in urinary isolates in hospitals (0.2-2.5%) than in the community (0.2-1.6%). ESBLs of genotype CTX-M predominated, with a significant (p<0.02) shift from the CTX-M-9 to CTX-M-1 phylogroup occurring among urinary ESBL-producing E.coli isolated early (n=41) as compared with late (n=221) in the study period. The increase in ESBL-producing E.coli was polyclonal, and only partly attributable to an increase (0-24%) in the number of O25b-ST131 isolates carrying CTX-M-15. The increase was prominent in men and in elderly patients, and warrants continued surveillance.
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| 4. |
- Helldal, Lisa, et al.
(author)
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Shifts in Extended-Spectrum Beta-Lactamase types with increasing prevalence of Escherichia coli producing ESBL
- 2010
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In: 20th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID), Vienna, Austria.
-
Conference paper (other academic/artistic)abstract
- Objectives: Contrary to other multidrug-resistant pathogens, the prevalence of bacteria producing extended-spectrum beta-lactamase (ESBL) is increasing rapidly in Sweden. In Europe, ESBL of CTX-M-, TEM-, OXA- and SHV-types are generally associated with E. coli infections, CTX-M being the most predominant. We have investigated how the prevalence of these types has changed during the last five years in the low endemic setting of western Sweden. Methods: Yearly resistance in urinary (approximately 10,000 isolates/year) and blood (approximately 250 isolates/year) E. coli during 2004-2008 were determined. Cephalosporin-resistant isolates were screened for ESBL, using a double-disk assay with clavulanic acid as the inhibitory agent. All ESBL-E. coli isolated in the region during the periods Sept 2003-April 2005 (n=46) and April 2008-March 2009 (n=256) were typed by multiplex-PCR, detecting CTX-M, TEM, OXA and SHV. CTX-M-positive isolates were sub-typed by real time Q-PCR for CTX-M-1, CTX-M-2 and CTXM-9 groups. Results: During 2004-2008, ESBL-producing E. coli strains increased from 0.3-1.5% in urinary and 0-1.4% in blood isolates. Resistance to quinolones and trimethoprim was observed in 60-80% of strains, as compared to less than 8% in non-ESBL-producing E. coli. The majority of the ESBL-E. coli strains possessed the CTX-M gene-type, increasing from 78% (36/46) in 2003-2005 to 93% (238/256) in 2008-2009. Between these time-periods, a marked shift occurred in the distribution of CTX-M types, in that strains with the CTX-M-9 group decreased from 42% (15/36) of isolates to 21% (51/238, p=0.01) and, simultaneously, strains with the CTX-M-1 group increased from 58% (21/36) to 78% (185/238, p= 0.02). Furthermore, strains of CTX-M-type exhibiting also TEM- and/or OXA increased to comprise 86% of cases, as compared to 75% previously. Similar trends were seen for community and hospital detected isolates and with no differences associated with age in affected patients. Conclusion: A steady increase in multidrug-resistant ESBL-E. coli, possessing the genes for multiple ESBL-types, was observed in western Sweden, contrary to the patterns of other multidrug-resistant bacteria. As ESBL has increased during the five-year study period, we detected a shift in the prevalence of ESBL-types, currently dominated by the CTX-M-1 group. These observations suggest that a novel ESBL-producing E. coli clone may have emerged in the area, which will be further investigated and presented.
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| 5. |
- Karami, Nahid, 1959, et al.
(author)
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Sub-Typing of Extended-Spectrum-beta-Lactamase-Producing Isolates from a Nosocomial Outbreak: Application of a 10-Loci Generic Escherichia coli Multi-Locus Variable Number Tandem Repeat Analysis
- 2013
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In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12
-
Journal article (peer-reviewed)abstract
- Extended-spectrum beta-lactamase producing Escherichia coli (ESBL-E. coli) were isolated from infants hospitalized in a neonatal, post-surgery ward during a four-month-long nosocomial outbreak and six-month follow-up period. A multi-locus variable number tandem repeat analysis (MLVA), using 10 loci (GECM-10), for 'generic' (i.e., non-STEC) E. coli was applied for sub-species-level (i.e., sub-typing) delineation and characterization of the bacterial isolates. Ten distinct GECM-10 types were detected among 50 isolates, correlating with the types defined by pulsed-field gel electrophoresis (PFGE), which is recognized to be the 'gold-standard' method for clinical epidemiological analyses. Multi-locus sequence typing (MLST), multiplex PCR genotyping of bla(CTX-M), bla(TEM), bla(OXA) and bla(SHV) genes and antibiotic resistance profiling, as well as a PCR assay specific for detecting isolates of the pandemic O25b-ST131 strain, further characterized the outbreak isolates. Two clusters of isolates with distinct GECM-10 types (G06-04 and G07-02), corresponding to two major PFGE types and the MLST-based sequence types (STs) 131 and 1444, respectively, were confirmed to be responsible for the outbreak. The application of GECM-10 sub-typing provided reliable, rapid and cost-effective epidemiological characterizations of the ESBL-producing isolates from a nosocomial outbreak that correlated with and may be used to replace the laborious PFGE protocol for analyzing generic E. coli.
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| 6. |
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| 7. |
- Åhrén, Christina, et al.
(author)
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Outbreak with ESBL (CTX-M)-producing Escherichia coli in a pediatric surgical ward
- 2009
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In: Scandinavian Society for Antimicrobial Chemotherapy 2009, September 3, Tromsø, Norway.
-
Conference paper (other academic/artistic)abstract
- Introduction: Nosocomial outbreaks with ESBL-producing bacteria in Scandinavia are still rare. In a surgical ward carrying mainly for small children with congenital gastrointestinal disorders spread with ESBL-producing bacteria most likely had been ongoing for three months when we detected the outbreak in December 2008. Five children with ESBL-infections had been cared for since September. Four had septicaemia as compared to no E.coli isolated in blood the previous year. Materials and methods: ESBL-detection has been performed according to routine methods. Positive isolates from patients hospitalised in the ward since 2007 were typed with pulse field gel electrophoresis (PFGE) and the PhP-phenplate method. Results: Altogether 125/169 children hospitalised during September-December were screened and 23 were positive for ESBL-producing bacteria (~50 available isolates), of which15 were only positive in stool. They had been hospitalised for a few days to several months. Four children probably constituted the infection pool. Twenty children carried the likely outbreak strain, but ESBL-producing E coli with four additional PFGE-types as well as Klebsiella pneumonie of one type were identified. Each type demonstrated up to three different resistance-patterns against trimetoprim, ciprofloxacin and tobramycin. Six children had multiple types. Discussion and Conclusion: Spread of ESBL-producing bacteria may go undetected for a long time when only clinical isolates are available. By comparing resistance pattern we missed this outbreak by more than a month. PFGE has been an invaluable tool in the investigation. Through cohorting, enforced hygiene routines, including food handling, for personnel, parents and siblings no new child has been infected (uninfected children are screened twice weekly) since the outbreak was detected.
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| 8. |
- Alaridah, Nader, et al.
(author)
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Transmission dynamics study of tuberculosis isolates with whole genome sequencing in southern Sweden
- 2019
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
-
Journal article (peer-reviewed)abstract
- Epidemiological contact tracing complemented with genotyping of clinical Mycobacterium tuberculosis isolates is important for understanding disease transmission. In Sweden, tuberculosis (TB) is mostly reported in migrant and homeless where epidemiologic contact tracing could pose a problem. This study compared epidemiologic linking with genotyping in a low burden country. Mycobacterium tuberculosis isolates (n = 93) collected at Scania University Hospital in Southern Sweden were analysed with the standard genotyping method mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR) and the results were compared with whole genome sequencing (WGS). Using a maximum of twelve single nucleotide polymorphisms (SNPs) as the upper threshold of genomic relatedness noted among hosts, we identified 18 clusters with WGS comprising 52 patients with overall pairwise genetic maximum distances ranging from zero to nine SNPs. MIRU-VNTR and WGS clustered the same isolates, although the distribution differed depending on MIRU-VNTR limitations. Both genotyping techniques identified clusters where epidemiologic linking was insufficient, although WGS had higher correlation with epidemiologic data. To summarize, WGS provided better resolution of transmission than MIRU-VNTR in a setting with low TB incidence. WGS predicted epidemiologic links better which could consolidate and correct the epidemiologically linked cases, avoiding thus false clustering.
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| 9. |
- Jönsson, Bodil, 1959, et al.
(author)
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Molecular epidemiology of Mycobacterium abscessus, with focus on cystic fibrosis.
- 2007
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In: Journal of clinical microbiology. - 0095-1137. ; 45:5, s. 1497-504
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Journal article (peer-reviewed)abstract
- Mycobacterium abscessus has been isolated increasingly often from the respiratory tracts of cystic fibrosis (CF) patients. It is not known whether these organisms are transmitted from person to person or acquired from environmental sources. Here, colony morphology and pulsed-field gel electrophoresis (PFGE) pattern were examined for 71 isolates of M. abscessus derived from 14 CF patients, three non-CF patients with chronic respiratory M. abscessus infection or colonization, one patient with mastoiditis, and four patients with infected wounds, as well as for six isolates identified as environmental contaminants in various clinical specimens. Contaminants and wound isolates mainly exhibited smooth colony morphology, while a rough colony phenotype was significantly associated with chronic airway colonization (P=0.014). Rough strains may exhibit increased airway-colonizing capacity, the cause of which remains to be determined. Examination by PFGE of consecutive isolates from the same patient showed that they all represented a single strain, even in cases where both smooth and rough isolates were present. When PFGE patterns were compared, it was shown that 24 patients had unique strains, while four patients harbored strains indistinguishable by PFGE. Two of these were siblings with CF. The other two patients, one of whom had CF, had not had contact with each other or with the siblings. Our results show that most patients colonized by M. abscessus in the airways have unique strains, indicating that these strains derive from the environment and that patient-to-patient transmission rarely occurs.
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| 10. |
- Svensson, Erik, 1959, et al.
(author)
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Cutaneous melioidosis in a Swedish tourist after the tsunami in 2004.
- 2006
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In: Scandinavian journal of infectious diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 38:1, s. 71-4
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Journal article (peer-reviewed)abstract
- A tourist from Sweden developed cutaneous melioidosis after the tsunami in Thailand on 26 December 2004. Melioidosis is a severe, chronic infection which is endemic in Thailand and is caused by Burkholderia pseudomallei. Persons with traumatic injuries inflicted by the tsunami have increased risks of being infected by B. pseudomallei and melioidosis should be suspected if abscesses of the skin or inner organs develop in the months or years after the trauma.
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| 11. |
- Abdeldaim, Guma, 1969-, et al.
(author)
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Multiplex quantitative PCR for detection of lower respiratory tract infection and meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis
- 2010
-
In: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 10, s. 310-
-
Journal article (peer-reviewed)abstract
- Background. Streptococcus pneumoniae and Haemophilus influenzae cause pneumonia and as Neisseria meningitidis they are important agents of meningitis. Although several PCR methods have been described for these bacteria the specificity is an underestimated problem. Here we present a quantitative multiplex real-time PCR (qmPCR) for detection of S. pneumoniae (9802 gene fragment), H. influenzae (omp P6 gene) and N. meningitidis (ctrA gene). The method was evaluated on bronchoalveolar lavage (BAL) samples from 156 adults with lower respiratory tract infection (LRTI) and 31 controls, and on 87 cerebrospinal fluid (CSF) samples from meningitis patients. Results. The analytical sensitivity was not affected by using a combined mixture of reagents and a combined DNA standard (S. pneumoniae/H. influenzae/N. meningitidis) in single tubes. By blood- and BAL-culture and S. pneumoniae urinary antigen test, S. pneumoniae and H. influenzae were aetiological agents in 21 and 31 of the LTRI patients, respectively. These pathogens were identified by qmPCR in 52 and 72 of the cases, respectively, yielding sensitivities and specificities of 95% and 75% for S. pneumoniae, and 90% and 65% for H. influenzae, respectively. When using a cut-off of 105 genome copies/mL for clinical positivity the sensitivities and specificities were 90% and 80% for S. pneumoniae, and 81% and 85% for H. influenzae, respectively. Of 44 culture negative but qmPCR positive for H. influenzae, 41 were confirmed by fucK PCR as H. influenzae. Of the 103 patients who had taken antibiotics prior to sampling, S. pneumoniae and H. influenzae were identified by culture in 6% and 20% of the cases, respectively, and by the qmPCR in 36% and 53% of the cases, respectively. In 87 CSF samples S. pneumoniae and N. meningitidis were identified by culture and/or 16 S rRNA in 14 and 10 samples and by qmPCR in 14 and 10 samples, respectively, giving a sensitivity of 100% and a specificity of 100% for both bacteria. Conclusions. The PCR provides increased sensitivity and the multiplex format facilitates diagnosis of S. pneumoniae, H. influenzae and N. meningitidis and the assay enable detection after antibiotic treatment has been installed. Quantification increases the specificity of the etiology for pneumonia.
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| 12. |
- Berntsson, Matilda, 1968, et al.
(author)
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Viral and bacterial aetiologies of male urethritis: findings of a high prevalence of Epstein-Barr virus
- 2010
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In: International Journal of STD & AIDS. - 0956-4624. ; 21:3, s. 191-194
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Journal article (peer-reviewed)abstract
- Male urethritis is one of the most common sexually transmitted infections (STIs). However, the aetiology is still unclear in many cases. In this study the prevalences of Epstein-Barr virus (EBV), herpes simplex virus type 1 (HSV-1), HSV-2, cytomegalovirus (CMV), adenovirus, Chlamydia trachomatis, Mycoplasma genitalium and Ureaplasma urealyticum (including subtyping) were investigated. Samples from 112 male STI attendants with microscopically verified urethritis and from a control group of 103 men without clinical or microscopic signs of urethritis were analysed. Prevalences in the urethritis group compared with the controls were as follows: EBV 21%, 6% (P < 0.01); C. trachomatis 15%, 3% (P < 0.01); M. genitalium 6%, 1% (P = 0.067) and U. urealyticum 10%, 10% (ns). The results for HSV-1, HSV-2, CMV and adenovirus were negative in patients, and therefore not analysed in the controls. EBV was shown to be an independent predictor of urethritis and may play a role in its pathogenesis.
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| 13. |
- Brink, Magnus, 1960, et al.
(author)
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Time window for positive cerebrospinal fluid broad-range bacterial PCR and Streptococcus pneumoniae immunochromatographic test in acute bacterial meningitis
- 2015
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In: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 47:12, s. 869-877
-
Journal article (peer-reviewed)abstract
- Background: Reliable microbiological tests are essential for the diagnosis of acute bacterial meningitis (ABM). In this study we investigated the time period after the start of antibiotic therapy during which culture, polymerase chain reaction (PCR) and the immunochromatographic test (ICT) are able to detect bacteria in cerebrospinal fluid (CSF). Methods: The study was performed on CSF samples from adults with ABM admitted to the Department of Infectious Diseases, Sahlgrenska University Hospital, Gothenburg, Sweden, from January 2007 to April 2014. In addition to the initial lumbar puncture (LP), the participants underwent one or two more LPs during 10 days following the start of antibiotics. The analyses performed on the CSF samples were culture, PCR and ICT. Results: The study comprised 70 CSF samples from 25 patients with ABM. A bacterium could be identified by CSF culture in 44%, by blood culture in 58% and by PCR in 100% of the patients. There were no positive CSF cultures in samples taken later than the day of starting antibiotics. PCR was positive in 89% on days 1-3, 70% on days 4-6 and 33% on days 7-10. For cases of pneumococcal meningitis, the ICT was positive in 88% on days 1-3, 90% on days 4-6 and 75% on days 7-10. Conclusions: This study shows that PCR is highly sensitive for bacterial detection in CSF samples taken up to 1 week into antibiotic therapy. The ICT is highly sensitive for the detection of pneumococci in CSF samples taken during the first week of antibiotic treatment.
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| 14. |
- Collins, Matthew D., et al.
(author)
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Arsenicicoccus bolidensis gen. nov., sp nov., a novel actinomycete isolated from contaminated lake sediment
- 2004
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In: INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY. - : Microbiology Society. - 1466-5026 .- 1466-5034. ; 54, s. 605-608
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Journal article (peer-reviewed)abstract
- An unknown Gram-positive, catalase-positive, facultatively anaerobic, non-spore-forming, coccus-shaped bacterium originating from sediment was characterized using phenotypic, molecular chemical and molecular phylogenetic methods. Chemical studies revealed the presence of a cell-wall murein based on ll-diaminopimelic acid (type ll-Dpm-glycine1), a complex mixture of saturated, monounsaturated and iso- and anteiso-methyl-branched, non-hydroxylated, long-chain cellular fatty acids and tetrahydrogenated menaquinones with eight isoprene units [MK-8(H4)] as the major respiratory lipoquinone. This combination of characteristics somewhat resembled members of the suborder Micrococcineae, but did not correspond to any currently described species. Comparative 16S rRNA gene sequencing confirmed that the unidentified coccus-shaped organism is a member of the Actinobacteria and represents a hitherto-unknown subline related to, albeit different from, a number of taxa including Intrasporangium, Janibacter, Terrabacter, Terracoccus and Ornithinicoccus. Based on phenotypic and phylogenetic considerations, it is proposed that the unknown bacterium originating from lake sediment be classified as a new genus and species, Arsenicicoccus bolidensis gen. nov., sp. nov. (type strain CCUG 47306T=DSM 15745T).
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| 15. |
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| 16. |
- Elfving, Kristina, et al.
(author)
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Real-time PCR threshold cycle (Ct) cut-offs help to identify agents causing acute childhood diarrhea in Zanzibar.
- 2014
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In: Journal of clinical microbiology. - 1098-660X. ; 52:3, s. 916-923
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Journal article (peer-reviewed)abstract
- Molecular assays might improve identification of causes of acute diarrheal disease, but may lead to more frequent detection of asymptomatic infections. In the present study real-time PCR targeting 14 pathogens was applied on rectal swabs from 330 children aged 2-59 months in Zanzibar, 165 with acute diarrhea and 165 asymptomatic controls. At least one pathogen was detected in 94% of patients and 84% of controls, with higher rates in patients for norovirus genogroup II (20% vs. 2.4%, p<0.0001), rotavirus (10% vs. 1.8%, p=0.003) and Cryptosporidium (30% vs. 11%, p<0.0001). Detection rates did not differ significantly for enterotoxigenic Escherichia coli (ETEC)-estA (33% vs. 24%), ETEC-eltB (44% vs. 46%), Shigella (35% vs. 33%), and Campylobacter (35% vs. 33%), but for these agents Ct (threshold cycle) values were lower (pathogen loads were higher) in sick children than in controls. In multivariate analysis, Ct values for norovirus genogroup II, rotavirus, Cryptosporidium, ETEC-estA and Shigella were independently associated with diarrhea. We conclude that this real-time PCR allows convenient detection of essentially all diarrheagenic agents, and provides Ct values that may be critical for interpretation of results for pathogens with similar detection rates in patients and controls. The results indicate that assessment of pathogen load may improve identification of agents causing gastroenteritis in children.
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| 17. |
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| 18. |
- Fritzell, Peter, et al.
(author)
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Detection of bacterial DNA in painful degenerated spinal discs in patients without signs of clinical infection.
- 2004
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In: European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. - : Springer Science and Business Media LLC. - 0940-6719. ; 13:8, s. 702-6
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Journal article (peer-reviewed)abstract
- A local inflammatory and potentially painful response, of which the ultimate cause is unknown, has been described in nervous tissues in contact with degenerated disc material in patients with low back and leg pain. With the rationale that a possible cause of such inflammation could be bacterial infection, we utilized PCR (polymerase chain reaction) amplification of the 16S rRNA (ribosomal RNA) gene followed by gene sequencing, to investigate whether bacterial DNA might be detected in the degenerative discs of 10 patients operated for disc herniation or post-discectomy syndrome. One patient with disc hernia harbored DNA homologous to Bacillus cereus, and in one patient suffering from post-discectomy syndrome, Citrobacter braaki/freundii DNA was detected. The finding demonstrates that 16S rRNA PCR can be a useful tool in search of bacterial DNA in degenerated discs, which in turn may be indicative of low-grade infection, manifesting itself only as pain rather than as clinical infection.
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| 19. |
- Grankvist, Anna, et al.
(author)
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Multilocus sequence analysis of clinical "candidatus neoehrlichia mikurensis" strains from Europe
- 2015
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In: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 53:10, s. 3126-3132
-
Journal article (peer-reviewed)abstract
- Copyright © 2015, American Society for Microbiology. All Rights Reserved. Candidatus Neoehrlichia mikurensis" is the tick-borne agent of neoehrlichiosis, an infectious disease that primarily affects immunocompromised patients. So far, the genetic variability of "Ca. Neoehrlichia" has been studied only by comparing 16S rRNA genes and groEL operon sequences. We describe the development and use of a multilocus sequence analysis (MLSA) protocol to characterize the genetic diversity of clinical "Ca. Neoehrlichia" strains in Europe and their relatedness to other species within the Anaplasmataceae family. Six genes were selected: ftsZ, clpB, gatB, lipA, groEL, and 16S rRNA. Each MLSA locus was amplified by real-time PCR, and the PCR products were sequenced. Phylogenetic trees of MLSA locus relatedness were constructed from aligned sequences. Blood samples from 12 patients with confirmed "Ca. Neoehrlichia" infection from Sweden (n9), the Czech Republic (n2), and Germany (n1) were analyzed with the MLSA protocol. Three of the Swedish strains exhibited identical lipA sequences, while the lipA sequences of the strains from the other nine patients were identical to each other. One of the Czech strains had one differing nucleotide in the clpB sequence from the sequences of the other 11 strains. All 12 strains had identical sequences for the genes 16S rRNA, ftsZ, gatB, and groEL. According to the MLSA, among the Anaplasmataceae, "Ca. Neoehrlichia" is most closely related to Ehrlichia ruminantium, less so to Anaplasma phagocytophilum, and least to Wolbachia endosymbionts. To conclude, three sequence types of infectious "Ca. Neoehrlichia" were identified: one in the west of Sweden, one in the Czech Republic, and one spread throughout Europe.
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| 20. |
- Johansson, Ewa, 1964, et al.
(author)
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Genotyping of Pseudomonas aeruginosa isolates from lung transplant recipients and aquatic environment-detected in-hospital transmission
- 2014
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In: Apmis. - : Wiley. - 0903-4641. ; 122:2, s. 85-91
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Journal article (peer-reviewed)abstract
- Lung infection with Pseudomonas aeruginosa is common in lung transplant recipients and may lead to severe complications. Bacteriological surveillance aims to detect transmission of microbes between hospital environment and patients. We sought to determine whether genotyping of P. aeruginosa isolates could improve identifications of pathways of infection. From 2004 to 2009, we performed genotyping with multiple-locus variable number of tandem repeats analysis (MLVA) and pulsed-field gel electrophoresis (PFGE) of P. aeruginosa isolates cultured from lung transplant recipients at Sahlgrenska University Hospital, Gothenburg. During a small outbreak in 2008, cultivation and genotyping of isolates from sink and drains samples from the hospital ward were performed. Pseudomona aeruginosa from 11/18 patients were genotyped to unique strains. The remaining seven patients were carriers of a P. aeruginosa strain of cluster A genotype. Pseudomona aeruginosa was isolated in 4/8 water samples, typed by MLVA also as cluster A genotype and confirmed by PFGE to be similar or identical to the isolates from four transplanted patients. In conclusion, genotyping of isolates revealed a clonal relationship between patient and water isolates, indicating in-hospital transmission of P. aeruginosa. We suggest genotyping with MLVA for rapid routine surveillance, with the PFGE method used for extended, confirmatory analyses.
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| 21. |
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| 22. |
- Kabayiza, Jean-Claude, et al.
(author)
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Comparison of rectal swabs and faeces for real-time PCR detection of enteric agents in Rwandan children with gastroenteritis
- 2013
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In: BMC Infectious Diseases. - 1471-2334. ; 13:1
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Journal article (peer-reviewed)abstract
- Abstract Background Molecular diagnostics have emerged as an efficient and feasible alternative for broad detection of pathogens in faeces. However, collection of stool samples is often impractical in both clinical work and in epidemiology studies. The aim of this study was to investigate the diagnostic performance of rectal swabs as compared with traditional faeces samples for detection of enteric agents by PCR. Method Three hundred twenty-six pairs of rectal swab and stool samples, obtained from Rwandan children aged 0.5-4.99 years, with or without diarrhoea, were analysed by multiple real-time PCR amplifying 3 viral, 6 bacterial and one protozoan target. Results For all agents there was a significant correlation (R2 0.31-0.85) between Ct values in faeces and rectal swabs. For most agents the Ct values, a marker for target concentration, were significantly lower (by 1–3 cycles) in faeces, indicating pathogen content up to ten times higher than in rectal swabs. Despite this, there was no significant difference in detection rate between faeces and rectal swabs for any agent, reflecting that pathogen concentration was far above the limit of detection in the majority of cases. Conclusion The similar detection rates and the Ct value correlations as compared with traditional faeces samples indicate that rectal swabs are accurate for real-time PCR-based identification of enteric agents and may be used also for quantitative estimation of pathogen load.
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| 23. |
- Kondori, Nahid, 1967, et al.
(author)
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Analyses of black fungi by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS): Species-level identification of clinical isolates of Exophiala dermatitidis
- 2015
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In: FEMS Microbiology Letters. - : Oxford University Press (OUP). - 0378-1097 .- 1574-6968. ; 362:1
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Journal article (peer-reviewed)abstract
- © FEMS 2014. Conventional mycological identifications based on the recognition of morphological characteristics can be problematic. A relatively new methodology applicable for the identification of microorganisms is based on the exploitation of taxonspecific mass patterns recorded from abundant cell proteins directly from whole-cell preparations, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This study reports the application of MALDI-TOF MS for the differentiation and identifications of black yeasts, isolated from the respiratory tracts of patients with cystic fibrosis (CF). Initial phenotypic and DNA sequence-based analyses identified these isolates to be Exophiala dermatitidis. The type strains of E. dermatitidis (CBS 207.35T) and other species of Exophiala were included in the MALDI-TOF MS analyses to establish the references for comparing the mass spectra of the clinical isolates of Exophiala. MALDI-TOF MS analyses exhibited extremely close relationships among the clinical isolates and with the spectra generated from the type strain of E. dermatitidis. The relationships observed between the E. dermatitidis strains from the MALDI-TOF MS profiling analyses were supported by DNA sequence-based analyses of the rRNA ITS1 and ITS2 regions. These data demonstrated the applicability of MALDI-TOF MS as a reliable, rapid and cost-effective method for the identification of isolates of E. dermatitidis and other clinically relevant fungi and yeasts that typically are difficult to identify by conventional methods.
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| 24. |
- Kondori, Nahid, 1967, et al.
(author)
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Development of IgG antibodies to Exophiala dermatitidis is associated with inflammatory responses in patients with cystic fibrosis.
- 2014
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In: Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society. - : Elsevier BV. - 1873-5010. ; 13:4, s. 391-399
-
Journal article (peer-reviewed)abstract
- The clinical importance of airway colonisation by the fungus Exophiala dermatitidis in patients with cystic fibrosis (CF) is unclear. We have previously shown that E. dermatitidis frequently colonises the airways of patients with CF. The aims of the present study were to determine whether patients who are colonised by E. dermatitidis have detectable fungal antigens in the circulation, develop anti-fungal antibodies, and show signs of inflammation and impaired respiratory function.
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| 25. |
- Rudolph, Thiemo, et al.
(author)
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16S rDNA PCR analysis of infectious keratitis: a case series
- 2004
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In: Acta Ophthalmologica Scandinavica. - 1395-3907. ; 82:4, s. 463-467
-
Journal article (peer-reviewed)abstract
- ABSTRACT. Purpose: To discuss the value of polymerase chain reaction (PCR) in the management of bacterial infectious keratitis. Methods: Corneal scrapings of four patients with severe infectious keratitis were analysed by culture and PCR of 16S ribosomal DNA (rDNA), followed by direct sequencing of the resulting amplicon. The medical history of the patients included laser-assisted in-situ keratomileusis (LASIK), penetrating keratoplasty (PKP) and trauma. Results: Using PCR we were able to identify a possible pathogen in all four cases, while bacterial cultures were either negative or did not correspond to the clinical picture. The identified bacteria were a Pseudomonas species, Abiotrophia defectiva, Stenotrophomonas maltophilia and Porphyromonas gingivalis. Conclusions: Analysis of corneal scrapings by 16S rDNA PCR should be considered as a supplement to standard microbiological procedures. However, the results of this relatively new method have to be interpreted carefully.
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| 26. |
- Skovbjerg, Susann, 1973, et al.
(author)
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Optimization of the detection of microbes in blood from immunocompromised patients with haematological malignancies.
- 2009
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In: Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases. - : Elsevier BV. - 1469-0691. ; 15:7, s. 680-3
-
Journal article (peer-reviewed)abstract
- The present study aimed to improve the rate of detection of blood-borne microbes by using PCRs with pan-bacterial and Candida specificity. Seventeen per cent of the blood samples (n=178) collected from 107 febrile patients with haematological malignancies were positive using standard culture (BacT/Alert system). Candida PCR was positive in 12 patients, only one of whom scored culture-positive. Bacterial PCR using fresh blood samples was often negative, but the detection rate increased when the blood was pre-incubated for 2 days. These data indicate that PCR assays might be a complement for the detection of blood-borne opportunists in immunocompromised haematology patients.
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| 27. |
- Söderström, A, et al.
(author)
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A large Escherichia coli O157 outbreak in Sweden associated with locally produced lettuce.
- 2008
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In: Foodborne pathogens and disease. - : Mary Ann Liebert Inc. - 1556-7125 .- 1535-3141. ; 5:3, s. 339-49
-
Journal article (peer-reviewed)abstract
- In 2005 a large outbreak of verotoxin-producing Escherichia coli (VTEC) occurred in Sweden. Cases were interviewed and cohort and case-control studies were conducted. Microbiological investigations were performed using polymerase chain reaction (PCR) to detect the Shiga-like toxin (Stx) genes followed by cultivation and pulsed-field gel electrophoresis. A total of 135 cases were recorded, including 11 cases of hemolytic uremic syndrome. The epidemiological investigations implicated lettuce as the most likely source of the outbreak, with an OR of 13.0 (CI 2.94-57.5) in the case-control study. The lettuce was irrigated by water from a small stream, and water samples were positive for Stx 2 by PCR. The identical VTEC O157 Stx 2 positive strain was isolated from the cases and in cattle at a farm upstream from the irrigation point. An active surveillance and reporting system was crucial and cooperation between all involved parties was essential for quickly identifying the cause of this outbreak. Handling of fresh greens from farm to table must be improved to minimize the risk of contamination.
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| 28. |
- Trollfors, Birger, 1947, et al.
(author)
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Pertussis after end of a mass vaccination project-End of the "vaccination honey-moon".
- 2011
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In: Vaccine. - : Elsevier BV. - 1873-2518 .- 0264-410X. ; 29:13, s. 2444-50
-
Journal article (peer-reviewed)abstract
- After 16 years of no vaccination against pertussis in Sweden, mass vaccination of infants and catch-up vaccination of children up to 10 years with a monocomponent pertussis toxoid vaccine was performed in the Greater Gothenburg area of Sweden between 1995 and 1999. At the end of the project in February 1999, 56% of all 10 year old children born in the Greater Gothenburg area had received 3 doses of the pertussis toxoid. No booster doses were given. This led to a temporary almost complete elimination of the disease. The aim of the present study was to follow the incidence of pertussis after end of the mass vaccination project (1999-2009) as it is reflected by laboratory verified cases (cultures and/or PCR) and pertussis hospitalizations. A reemergence of pertussis was seen from the end of 1999 with a peak in 2004 followed by a decrease when booster doses to both 6 and 10 year old children were introduced in 2005-2006. From July 1, 1999 through December 31, 2009 a total of 1973 cases were diagnosed with culture or PCR. The disease was prevalent in all age groups. The highest documented incidence was seen in infants younger than 12 months. 450 patients with verified pertussis had received 3 doses of the pertussis toxoid vaccine in the mass vaccination project and some other trials (comprising a total of 69,423 children). The mean time from the last dose to the laboratory verification of pertussis was 5 years in these 450 cases. There were 128 hospitalizations, 106 of which were in infants. In conclusion, pertussis is still not eliminated from the area. Booster doses are needed but the numbers and optimal timing are not known.
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| 29. |
- Welinder-Olsson, Christina, 1959, et al.
(author)
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Comparison of broad-range bacterial PCR and culture of cerebrospinal fluid for diagnosis of community-acquired bacterial meningitis.
- 2007
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In: Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases. - : Elsevier BV. - 1198-743X. ; 13:9, s. 879-86
-
Journal article (peer-reviewed)abstract
- Appropriate, rapid and reliable laboratory tests are essential for the diagnosis and optimal antibiotic therapy of acute bacterial meningitis. Broad-range bacterial PCR, combined with DNA sequencing, was compared with culture-based methods for examining cerebrospinal fluid (CSF) samples from patients with suspected meningitis. In total, 345 CSF specimens from 345 patients were analysed, with acute community-acquired bacterial meningitis being diagnosed in 74 patients. The CSF of 25 patients was positive by both PCR and culture; 26 patients had CSF specimens positive by PCR only, and 14 patients had specimens positive by culture only. The sensitivity of PCR and culture for clinically relevant meningitis was 59% (44/74) and 43% (32/74), respectively, while the specificity was 97% (264/271) and 97% (264/271), respectively. The commonest bacterial rRNA gene sequences detected by PCR only were those of Streptococcus pneumoniae and Neisseria meningitidis (n = 12). PCR failed to detect the bacterial rRNA gene in seven specimens from patients with symptoms compatible with acute bacterial meningitis. Overall, the results demonstrated that PCR in conjunction with sequencing may be a useful tool in the diagnosis of bacterial meningitis. PCR is particularly useful for analysing CSF from patients who have been treated with antibiotics before lumbar puncture.
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| 30. |
- Welinder-Olsson, Christina, 1959, et al.
(author)
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EHEC outbreak among staff at a children's hospital--use of PCR for verocytotoxin detection and PFGE for epidemiological investigation.
- 2004
-
In: Epidemiology and infection. - 0950-2688. ; 132:1, s. 43-9
-
Journal article (peer-reviewed)abstract
- This is the first report of a major foodborne outbreak of enterohaemorrhagic Escherichia coli (EHEC) in Sweden. It occurred among the nursing staff at a children's hospital with approximately 1600 employees. Contaminated lettuce was the most likely source of infection. Nine persons were culture-positive for Escherichia coli (E. coli) O157 and verocytotoxin-positive by PCR and a further two were verocytotoxin-positive by PCR only. All 11 EHEC-positive individuals had attended a party for approximately 250 staff members, which was held at the hospital. In a questionnaire 37 persons stated that they had symptoms consistent with EHEC infection during the weeks after the party. There was no evidence of secondary transmission from staff to patients. The value of PCR as a sensitive and fast method for diagnosis is discussed in this paper. Pulsed-field gel electrophoresis (PFGE) was used to ascertain that staff members were infected by the same clone, and that two patients with E. coli O157 infection were not.
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| 31. |
- Welinder-Olsson, Christina, 1959, et al.
(author)
-
Enterohemorrhagic Escherichia coli (EHEC).
- 2005
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In: Scandinavian journal of infectious diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 37:6-7, s. 405-16
-
Journal article (peer-reviewed)abstract
- Enterohaemorrhagic Escherichia coli has since the last 2 decades been known to cause severe and bloody diarrhoea as well as haemorrhagic colitis (HC) and haemorrhagic uraemic syndrome (HUS) especially among children. The importance of screening for EHEC among children and older patients with severe symptoms is apparent. Production of the verocytotoxins VT1 and VT2 are the main features of EHEC, and the VT types and mode of action during human infection is described. There are, however, other features adding to the pathogenicity. In this review we deal with the importance of properties such as fimbriae and adhesins as well as systems to meet the bacterial need for iron during infection. These factors are probably important for the establishment of EHEC in the gut and add to the bacterial virulence. It has now become evident that VT producing E. coli, irrespective of serogroup, might be human pathogens. We conclude that knowledge of the different possible virulence factors adds to the possibility of separating more virulent from less virulent isolates.
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| 32. |
- Welinder-Olsson, Christina, 1959
(author)
-
Enterohemorrhagic Escherichia coli, EHEC.Microbiological diagnosis, characterisation and clinical bacteriological aspects
- 2004
-
Doctoral thesis (other academic/artistic)abstract
- Enterohemorrhagic Escherichia coli (EHEC) constitutes a group of E. coli that in the past two decades has been the cause of several outbreaks of gastrointestinal disease. The microorganism causes hemorrhagic colitis (HC) and haemolytic uremic syndrome (HUS) in 5-10% of the patients, 30% of the HUS patients develop remaining kidney injuries. The capacity to control EHEC disease and to limit the scale of outbreaks is dependent upon prompt diagnosis and identification of the source of infection. Cattle are the principal reservoir of EHEC and foodstuffs, which presumably have come into contact with domestic animal manure and/or are inadequately pasteurised, are important vehicles of infection. The predominating virulence factor of EHEC is the verocytotoxin first identified in an E. coli of serogroup O157:H7. In the present study, the PCR technique with primers detecting the verocytotoxin genes was shown to be a fast, sensitive and specific method to screen for and identify EHEC. The study contributes to the knowledge and understanding that also EHEC non-O157 are pathogenic and that all verocytotoxin producing E. coli should be looked after among patients with diarrhoea, HC and HUS. The importance of quick identification was exemplified in an outbreak of EHEC among the staff at the children s hospital in Göteborg, Sweden. As the outbreak was promptly identified, partly thanks to the PCR technique, no further spread to other staff members or patients occurred. In the present thesis, pulsed-field gel electrophoresis (PFGE) was used and the method was shown to be very useful in the epidemiological work to separate single cases of EHEC from outbreaks. In order to further characterise EHEC non-O157, the presence of additional chromosomal and plasmid genes probably involved in the pathogenesis were analysed as these genes have been found in EHEC O157. The gene coding for intimin, enabling tight attachment to epithelial cells of the intestine was also often present among EHEC non-O157. Moreover, the gene coding for an enterohemolysin possibly supporting the bacterial need for iron was especially often present among EHEC isolated from patients with severe symptoms. Further, the study has shown that the gene coding for aerobactin seems to be able to compensate for the absence of enterohemolysin and that also the type 1 fimbriae may be valuable to obtain a niche in the gut. A comparative study of verocytotoxin producing E. coli in cattle showed that there is a significantly lower amount of E. coli harbouring the intimin gene and the gene coding for aerobactin, supporting the assumption that not all verocytotoxin producing E. coli in cattle are pathogenic. In conclusion, methods identifying the verocytotoxines or their genes should be used to identify EHEC of all serogroups. PCR is preferable as it is a fast, sensitive and specific method. Genes coding for intimin, enterohemolysin and aerobactin adds to the pathogenicity of EHEC. These genes are not that common among isolates from cattle. PFGE is a most valuable tool for epidemiological tracing of EHEC.
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| 33. |
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| 34. |
- Welinder-Olsson, Christina, 1959, et al.
(author)
-
Genetic profiling of enterohemorrhagic Escherichia coli strains in relation to clonality and clinical signs of infection.
- 2002
-
In: Journal of clinical microbiology. - 0095-1137. ; 40:3, s. 959-64
-
Journal article (peer-reviewed)abstract
- Sixty-seven human strains of enterohemorrhagic Escherichia coli (EHEC) (from patients with more or less severe symptoms) were serogrouped and arranged according to pulsed-field gel electrophoresis (PFGE) patterns. We used PCR to investigate the strains according to known or putative virulence factors, and associations with disease were studied. All EHEC strains with the same PFGE pattern belonged to the same serogroup. On the contrary, two serogroups (O157 and O8) included strains with different PFGE patterns. We found several different combinations of chromosomal and plasmid-borne determinants, encoding the putative virulence factors, among the strains. As judged from clinical symptoms, there was no marked difference in pathogenicity among the strains and their combinations of virulence traits. All strains of O157 had the genes coding for verocytotoxin (VT) 2, intimin (eaeA), E. coli hemolysin (E-hly), and secreted serine protease (espP). Among EHEC non-O157 strains, the genes coding for VT1 and VT2 were equally dispersed. EaeA positivity was just as common among VT1- as VT2-positive strains. Among the plasmid-borne determinants, E-hly and espP were the most common and E-hly might be a pathogenicity marker among EHEC non-O157 strains. The conclusion is that PFGE is a very useful tool in epidemiological studies. The EHEC plasmids are heterogeneous in their gene composition, with the four plasmid-borne determinants found in many combinations. There was no reliable correlation between chromosomal and plasmid-borne virulence factors and human disease.
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| 35. |
- Welinder-Olsson, Christina, 1959, et al.
(author)
-
Improved microbiological techniques using the polymerase chain reaction and pulsed-field gel electrophoresis for diagnosis and follow-up of enterohaemorrhagic Escherichia coli infection.
- 2000
-
In: European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology. - 0934-9723. ; 19:11, s. 843-51
-
Journal article (peer-reviewed)abstract
- The aims of the present investigation were to evaluate the microbiological diagnostic procedures, especially polymerase chain reaction (PCR) versus culture and seroagglutination, in relation to the clinical features of enterohaemorrhagic Escherichia coli (EHEC) infection and to study the status of EHEC in the western part of Sweden. During 1997 and 1998, stool specimens from 3,948 patients were analysed by PCR for the presence of EHEC with verotoxin (VT)1- and/or VT2-producing DNA sequences. The stool specimens were also cultured for Escherichia coli O157:H7, Salmonella, Campylobacter, Shigella and Yersinia. Fifty-five patients were positive by PCR. Thirty-nine patients were positive for EHEC by PCR and culture. Of these, 29 were infected with EHEC serogroup O157:H7 strains. All EHEC isolates were analysed by pulsed-field gel electrophoresis (PFGE); 17 different clones were identified. Studies on the duration of the presence of EHEC in the gut showed that EHEC often disappears rather quickly, i.e. within 2 weeks. In one patient, however, EHEC remained for several months. In conclusion, PCR, rather than culture and agglutination, should be the method of choice for microbiological diagnosis of EHEC infection. PCR is more sensitive than culture for detecting EHEC in the gut.
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| 36. |
- Welinder-Olsson, Christina, 1959, et al.
(author)
-
Virulence genes in verocytotoxigenic Escherichia coli strains isolated from humans and cattle.
- 2005
-
In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 0903-4641. ; 113:9, s. 577-85
-
Journal article (peer-reviewed)abstract
- Verocytotoxigenic Escherichia coli (VTEC) causing diarrhoea, haemorrhagic colitis and haemolytic-uremic syndrome usually have additional traits such as the adhesin intimin and a large plasmid that seems to increase virulence. There are, however, isolates of VTEC causing serious symptoms that do not harbour these traits. In the present study we have used PCR with primers detecting adhesin genes other than eaeA, namely fimA, papC, sfaD/sfaE and daaE. We have also used PCR to detect the genes hlyA and iutA that besides the plasmid-borne gene E-hly possibly support the bacterial access to iron. The aim of the study was to identify and compare the presence of virulence genes in VTEC isolates of human and cattle origin. The main finding was that the absence of E-hly might be compensated for by the gene iutA coding for aerobactin or hlyA coding for alpha-haemolysin as 94% of the human VTEC isolates had at least one of these genes. Interestingly, only 45% of VTEC isolated from cattle had any of these genes. We propose that this might be the reason for the relatively low incidence of symptomatic VTEC infections among humans in relation to the high number of VTEC among cattle.
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