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Characterisation of Chlamydia trachomatis by ompA sequencing and multilocus sequence typing in a Swedish county before and after identification of the new variant
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Bacteriology. (Björn Herrmann)
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Bacteriology. (Björn Herrmann)
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2010 (English)In: Sexually Transmitted Infections, ISSN 1368-4973, E-ISSN 1472-3263, Vol. 86, no 1, 56-60 p.Article in journal (Refereed) Published
Abstract [en]

OBJECTIVES: In 2006 a new variant of Chlamydia trachomatis (nvCT), with a deletion in the cryptic plasmid, was reported in Sweden. This deletion included the targets for the genetic diagnostic systems used in many clinical laboratories and resulted in thousands of false-negative results. The aim of this study was to characterise consecutive Chlamydia tissue culture-positive samples from 2006 in Orebro County, after identification of the nvCT, and to compare the results from samples collected in the same county in 1999-2000. The study also aimed to evaluate the discriminatory capacity of multilocus sequence typing (MLST) compared with ompA sequencing. METHODS: ompA sequencing and MLST was used to characterise 100 consecutive Chlamydia tissue culture-positive samples. RESULTS: A significant (p<0.001) increase of genotype E, from 47% in 1999-2000 to 69% in 2006, was detected. All 41 nvCT isolates from 2006 displayed an identical ompA genotype E and MLST profile. Excluding the nvCT isolates, the distribution of ompA genotypes is similar to the genotyping results from 1999-2000. Among the wild-type genotype E isolates from 2006, 14 unique MLST sequence types were obtained from 26 isolates while they were identical in ompA genotyping. The discriminatory power (D) of C trachomatis strains in this material was 83.5% using the MLST system compared with 49.5% utilising ompA sequencing. CONCLUSION: In all, MLST enables improved studies of the molecular epidemiology of C trachomatis. All nvCT isolates from 2006 displayed an identical ompA genotype E and MLST profile, which strongly indicates a clonal spread of the nvCT.

Place, publisher, year, edition, pages
2010. Vol. 86, no 1, 56-60 p.
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-125330DOI: 10.1136/sti.2009.037572ISI: 000274525800014PubMedID: 19837730OAI: oai:DiVA.org:uu-125330DiVA: diva2:319402
Available from: 2010-05-17 Created: 2010-05-17 Last updated: 2011-09-07Bibliographically approved
In thesis
1. High Resolution Genotyping of Chlamydia trachomatis
Open this publication in new window or tab >>High Resolution Genotyping of Chlamydia trachomatis
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Chlamydia trachomatis is an obligate intracellular bacterium of major human health concern, causing urogential chlamydia infections, lymphogranuloma venereum (LGV) and trachoma. Chlamydia is one of the most common sexually transmitted infections worldwide and can cause infertility.

In the first four papers described herein we used a high resolution multilocus sequence typing (MLST) system to investigate the epidemiology of C. trachomatis, and showed that MLST is superior to conventional ompA genotyping with respect to resolution. In the fifth paper we simplified the methodology by developing and validating a multilocus typing (MLT) DNA microarray based on the MLST system.

In more detail, MLST analysis of consecutive specimens from 2006 in Örebro County in Sweden, and comparison to specimens from 1999-2000, showed that the new variant C. trachomatis (nvCT) is monoclonal and likely has appeared in recent years.

MLST analysis of LGV specimens from men who have sex with men (MSM) showed that the increase of LGV in Europe in the last decade indeed was a clonal outbreak, contrary to the USA where LGV might have been present all along.

In the third paper, clinical symptoms could not be correlated with the MLST genotypes, suggesting, together with the combined results of all previous studies, that bacterial factors, if important, need to be understood in the context of host factors.

MLST analysis of specimens from a high incidence C. trachomatis area in North Norway revealed interesting epidemiological details concerning unusual genetic variants, the nvCT and MSM, but found no significant difference in genetic diversity compared to two other geographic areas in Norway.

Lastly, we developed a MLT array that provides high resolution while being rapid and cost-effective, which makes it an interesting alternative for C. trachomatis genotyping.

In conclusion, the MLST system and the MLT array have proven to be useful tools and should now be applied in further investigations to improve our understanding of C. trachomatis epidemiology.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2011. 48 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 690
Chlamydia trachomatis: multilocus sequence typing: MLST: genotyping: lymphogranuloma venereum: new variant C. tracomatis: nvCT: multilocus typing DNA microarray: MLT array
National Category
Microbiology in the medical area
Research subject
Medical Science
urn:nbn:se:uu:diva-156751 (URN)978-91-554-8121-6 (ISBN)
Public defence
2011-09-29, Hörsalen, Klinisk mikrobiologi, Akademiska sjukhuset, Dag Hammarskjöldsväg 17, Uppsala, 09:15 (English)
Available from: 2011-08-30 Created: 2011-08-09 Last updated: 2011-09-08

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