Background The yaws treponemes, Treponema pallidum ssp. pertenue (TPE) strains, are closely related to syphilis causing strains of Treponema pallidum ssp. pallidum (TPA). Both yaws and syphilis are ...distinguished on the basis of epidemiological characteristics, clinical symptoms, and several genetic signatures of the corresponding causative agents. Methodology/Principal Findings To precisely define genetic differences between TPA and TPE, high-quality whole genome sequences of three TPE strains (Samoa D, CDC-2, Gauthier) were determined using next-generation sequencing techniques. TPE genome sequences were compared to four genomes of TPA strains (Nichols, DAL-1, SS14, Chicago). The genome structure was identical in all three TPE strains with similar length ranging between 1,139,330 bp and 1,139,744 bp. No major genome rearrangements were found when compared to the four TPA genomes. The whole genome nucleotide divergence (dA) between TPA and TPE subspecies was 4.7 and 4.8 times higher than the observed nucleotide diversity (π) among TPA and TPE strains, respectively, corresponding to 99.8% identity between TPA and TPE genomes. A set of 97 (9.9%) TPE genes encoded proteins containing two or more amino acid replacements or other major sequence changes. The TPE divergent genes were mostly from the group encoding potential virulence factors and genes encoding proteins with unknown function. Conclusions/Significance Hypothetical genes, with genetic differences, consistently found between TPE and TPA strains are candidates for syphilitic treponemes virulence factors. Seventeen TPE genes were predicted under positive selection, and eleven of them coded either for predicted exported proteins or membrane proteins suggesting their possible association with the cell surface. Sequence changes between TPE and TPA strains and changes specific to individual strains represent suitable targets for subspecies- and strain-specific molecular diagnostics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Sexually Transmitted Treponematoses Mikalová, Lenka; Šmajs, David
Diagnostics to Pathogenomics of Sexually Transmitted Infections,
11/2018
Book Chapter
The majority of sexually transmitted treponematoses are caused by the syphilis spirochete, Treponema pallidum subsp. pallidum (TPA). However, there is increasing evidence that T. pallidum subsp. ...endemicum (TEN), which causes bejel, can also be transmitted through sexual contact. Therefore, this chapter describes treponematoses caused by both TPA and TEN strains and summarizes basic information together with new trends and current progress in treponemal genomics, pathogenesis, molecular typing, epidemiology, diagnostics, treatment, and vaccine development. Current data on molecular typing of contemporary circulating syphilis‐causing strains of various geographic origin revealed that SS14‐like strains predominate worldwide among clinical isolates, although the ultimate reasons of this phenomenon remain unknown. Molecular analysis of syphilis‐causing strains has also revealed a high prevalence of macrolide resistance in syphilis‐causing strains with marked geographical differences. Despite the existence of effective penicillin treatment, syphilis still represents a major global health problem, which emphasizes the importance of vaccine development.
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