Phylogenetic analysis of pbp genes in treponemes

BACKGROUND β-Lactamases are the main cause of bacterial resistance to penicillin, cephalosporins, and related β-lactam compounds. The presence of the novel penicillin-binding protein (pbp) Tp47 in Treponema pallidum has been reported to be a well-known mechanism for turnover of b-lactam antibiotics. Although, T. pallidum remains sensitive to penicillin, clinically significant resistance to macrolides has emerged in many developing countries. The genome sequence of T. pallidum has shown the presence of genes encoding pbp, but there are no current reports of the presence of mobile plasmids. METHODS The phylogenetic analysis is used to study the diversity of chromosomal pbp genes and its relatedness to Tp47 in Treponema species. RESULTS In our study, genes encoding penicillin-binding proteins that showed significant similarity to each other appeared in separate clusters. CONCLUSION Tp47 showed no substantial similarity to other β-lactamases in treponemes. The relatedness of Treponema denticola to other treponemes, including T. pallidum, and the reported presence of natural mobile antibiotic determinants highlight the importance of investigating the diversity of pbp genes in Treponema species. This will lead to a greater understanding of its potential to develop additional antibiotic resistance via horizontal gene transfer that could seriously compromise the treatment and control of syphilis.