Molecular detection and typing of Treponema pallidum ssp. pallidum in clinical samples based on sequencing of TP0136, TP0548 and 23S rRNA genes
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| Year of publication | 2011 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Syphilis, caused by the spirochete Treponema pallidum subsp. pallidum (TPA), is a sexually transmitted infectious disease with worldwide occurrence. The bacterium TPA cannot be cultivated in vitro, therefore laboratory diagnostics is traditionally made by microscopy and serology testing, which do not provide epidemiological data. Molecular detection of treponemes could type the clinical samples and provide the antibiotic susceptibility information. During the years 2004-2010, 294 patients (415 samples) were tested for the presence of treponemal DNA. Primary screening of clinical specimens included nested PCR detection of two TPA specific loci (tmpC and polA genes). Out of 294 patients, 91 patients were PCR positive. PCR positive patients were more often in the primary stage of syphilis (p=0.0003) compared to the control (PCR negative) group of syphilis seropositive patients. Treponemal DNA was detected in 4 types of clinical material: genitoanal, pharyngeal and skin swabs (75 samples), whole blood samples (42), cerebrospinal fluid (1) and blood serum (1). Molecular typing method was based on amplification and sequencing of two sequentially variable genes including TP0136 and TP0548 together with the 23S rRNA gene, where the mutation in position A2058G or A2059G cause the macrolide resistance. Out of 91 patients with PCR positive samples, 49 patients were completely typed (sequences of TP0136, TP0548 and 23S rRNA genes were determined), 15 patients were partially typed (only two out of 3 loci were detected). Nine different genotypes among the 64 completely or partially typed patients were found. 35.6% of treponemal strains were resistant to macrolide antibiotics. Identified subtypes of TPA strains were further typed with the CDC typing system for TPA treponemes (comprising analysis of the arp and tpr genes). The obtained unique TP0136 and TP0548 sequences were found to combine independently with CDC subtypes indicating their potential for more detailed genetic characterization of TPA-containing clinical samples. |
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