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Multilocus Sequence Typing of Genital Chlamydia trachomatis in Norway Reveals Multiple New Sequence Types and a Large Genetic Diversity
Department of Microbiology and Infection Control, University Hospital of North Norway, N - 9038 Tromsø, Norway and Faculty of Health Sciences, University of Tromsø, N – 9037 Tromsø, Norway.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Bacteriology.
Department of Microbiology and Infection Control, University Hospital of North Norway, N - 9038 Tromsø, Norway and Faculty of Health Sciences, University of Tromsø, N – 9037 Tromsø, Norway.
Department of Microbiology and Infection Control, University Hospital of North Norway, N - 9038 Tromsø, Norway.
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2012 (English)In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 3, e34452- p.Article in journal (Refereed) Published
Abstract [en]

Background: The Chlamydia trachomatis incidence rate in Finnmark, the most northern and sparsely populated county in Norway, has been twice the national average. This population based cross-sectional study among Finnmark high school students had the following aims: i) to examine distribution of multilocus sequence types (STs) of C. trachomatis in a previously unmapped area, ii) to compare chlamydia genetic diversity in Finnmark with that of two urban regions, and iii) to compare discriminatory capacity of multilocus sequence typing (MLST) with conventional ompA sequencing in a large number of chlamydia specimens.

Methodology: ompA sequencing and a high-resolution MLST system based on PCR amplification and DNA sequencing of five highly variable genetic regions were used. Eighty chlamydia specimens from adolescents aged 15-20 years in Finnmark were collected in five high schools (n = 60) and from routine clinical samples in the laboratory (n = 20). These were compared to routine clinical samples from adolescents in Tromso (n = 80) and Trondheim (n = 88), capitals of North and Central Norway, respectively.

Principal Findings: ompA sequencing detected 11 genotypes in 248 specimens from all three areas. MLST displayed 50 STs providing a five-fold higher resolution. Two-thirds of all STs were novel. The common ompA E/Bour genotype comprised 46% and resolved into 24 different STs. MLST identified the Swedish new variant of C. trachomatis not discriminated by ompA sequencing. Simpson's discriminatory index (D) was 0.93 for MLST, while a corrected D-c was 0.97. There were no statistically significant differences in ST genetic diversity between geographic areas. Finnmark had an atypical genovar distribution with G being predominant. This was mainly due to expansion of specific STs of which the novel ST161 was unique for Finnmark.

Conclusions/Significance: MLST revealed multiple new STs and a larger genetic diversity in comparison to ompA sequencing and proved to be a useful tool in molecular epidemiology of chlamydia infections.

Place, publisher, year, edition, pages
2012. Vol. 7, no 3, e34452- p.
Keyword [en]
Chlamydia trachomatis epidemiology: multilocus sequence typing: novel genotypes: Swedish new variant of Chlamydia trachomatis
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-156747DOI: 10.1371/journal.pone.0034452ISI: 000304489000111OAI: diva2:433143
Manuscript title: High-resolution Multilocus Sequence Typing of Chlamydia trachomatis reveals multiple new genotypes in North and Central NorwayAvailable from: 2011-08-09 Created: 2011-08-09 Last updated: 2012-06-28Bibliographically 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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