Characterisation of Chlamydia trachomatis by ompA sequencing and multilocus sequence typing in a Swedish county before and after identification of the new variant

Abstract

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.

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

“…Of the included samples, 203 (55%) were successfully genotyped by MLST and ompA sequencing, and these samples were obtained in equal numbers for the three countries: 67 samples (46 rectal swabs and 21 urine specimens) from Sweden, 69 rectal samples from the Netherlands, and 67 rectal samples from the United States. For the groups of heterosexual women, 153 fully typed samples were included, of which 60 originated from Sweden and 93 originated from the Netherlands (4,7,16).…”

“…From Sweden, 40 culture isolates were collected at the Ö rebro University Hospital in 2006. To minimize sampling bias, cases of the new variant were not included in the present study, since they represent a clonal outbreak (16 (4). Full MLST data were available for these samples.…”

“…With the exception of 44 Dutch specimens, the MLST target regions and ompA were amplified in Uppsala by using previously described primers (6,12,16,18). These primers are summarized in Table 1.…”

“…Another clonal outbreak occurred mainly in Sweden and was due to a new variant of C. trachomatis, leading to the generation of false-negative results by some molecular detection systems. This variant is a genovar E strain and has not been reported to occur in MSM (13,16,19).…”

“…Our MLST system is based on the PCR amplification and DNA sequencing of five highly variable but stable genetic regions (21). It has been applied to specimens from heterosexual populations in a number of studies and has shown up to a 5-fold-higher resolution than ompA genotyping, revealing a large diversity of clinical strains missed by ompA genovar typing (7,11,16,18). In a modified version, high resolution was retained but sensitivity was im-proved by targeting smaller parts of the polymorphic genetic regions (4).…”