Sequencing-based Molecular Typing of Treponema pallidum Strains in the Czech Republic: All Identified Genotypes are Related to the Sequence of the SS14 Strain

Abstract

A set of 415 clinical samples isolated from 294 patients suspected of having syphilis collected in the Czech Republic between 2004 and 2010 was tested for the presence of treponemal DNA. Standard serological tests showed that 197 patients were syphilis-seropositive and 97 patients were syphilis-seronegative. In each sample, PCR tests for polA (TP0105), tmpC (TP0319), TP0136, TP0548 and 23S rRNA genes were performed. Samples taken from 91 patients were PCR-positive. Molecular typing of treponemal DNA was based on the sequencing of TP0136, TP0548 and 23S rRNA genes. Treponemal DNA was typeable in samples taken from 64 PCR-positive patients and 9 different genotypes were found. The proportion of treponemal strains resistant to macrolide antibiotics was 37.3%. In the DNA samples taken from 39 patients, a parallel treponemal typing approved by Centers for Disease Control and Prevention was performed. The variants of arp and tpr genes appear to combine independently with sequence variants of TP0136, TP0548 and 23S rRNA genes.

Molecular Typing of Treponema pallidum in the Czech Republic during 2011 to 2013: Increased Prevalence of Identified Genotypes and of Isolates with Macrolide Resistance

“…As in our previous study (5), the relatively high number of PCRnegative specimens (45%) from syphilis-seropositive patients likely reflects undetectable amounts of treponemal DNA in biological material, especially in blood samples. However, the use of larger volumes of whole blood for isolation of DNA could potentially help increase the rate of PCR-positive blood samples.…”

“…Increases in the variability of T. pallidum subsp. pallidum genotypes and also in the prevalence of macrolide resistance-encoding alleles at the 23S rRNA gene locus (A2058G and A2059G mutations) were noted compared to those in a previous study in our laboratory of clinical isolates from the same geographical region (5).…”

“…Recently, this typing system has been improved by the additional determination of the number of repeats in the rpsA gene (3) and by additional sequence analysis of the TP0548 locus (4), which has been used for sequencing-based molecular typing of syphilis treponemes since 2006 (5). The reproducibility of the CDC typing system was recently questioned by the identification of multiple T. pallidum subsp.…”

“…pallidum subtypes in clinical samples isolated from a single patient (7). In parallel with the CDC typing scheme, sequencing-based molecular typing based on sequencing of the TP0136, TP0548, and 23S rRNA genes has been introduced and tested (5,8).…”

“…pallidum isolates and allowed the determination of the prevalence of macrolide-resistant T. pallidum subsp. pallidum strains (2)(3)(4)(5)(6).…”