Surveillance Study Of Treponema Pallidum For TetB Gene And Tetracycline Resistance Mutations In 16S RRNA

Background: Syphilis is a complex systemic illness caused by the spirochete Treponema pallidum which is transmitted both sexually and from mother-to-child. Treponema pallidum may invade the body organs(systemic skin and mucous membranes, cardiovascular,neurological, skeletal, etc.), resulting in multi-systematic damage and a wide variety of signs and symptoms. Penicillin is the preferred drug for treatment of syphilis. Macrolide antibiotics,doxycycline and cephalosporins are recommended as alternate agents in nonpregnant patients if they are allergic to penicillin or unable to tolerate treatment with BPG. The major mechanisms may be acquisition of tetracycline resistant genes as well as point mutations in16 S rRNA gene(nt 926 to 928 and 939, nt 965–967 and 1058). To date, thirty-eight acquired tetracycline resistant genes are known and the tetB gene is the most commonly carried Gram-negative efflux gene identified in Gram-negative bacteria as well as Treponema deticola. Here, we aimed to identify the resistance gene(tetB) and mutations(nt 926 to 928 and 939, nt 965–967 and 1058) in the 16 S rRNA gene of T. pallidum in Shandong.Objective: 1. To detect the tetracycline resistant gene(tetB) gene and 16 S rRNA mutations of TP in Shandong. 2. To evaluate the efficacy of tetracycline in treatment of early syphilis in Shandong province. 3. To assess whether tetracycline antibiotics are still suitable as an alternative drug therapy for syphilis.Methods: DNA was extracted from anogenital lesions presenting with syphilis, and was detected by a real-time polymerase chain reaction(PCR) assay that targets the DNA polymerase A gene(pol A) of T.pallidum. Positive samples amplify the 16 S rRNA genes by PCR and direct sequencing of the 16 S rRNA genes and sequence for the existence of tetB gene.Results: 15 of 171 specimens were detected positive for tetB gene. However, none mutations associated with tetracycline resistance was detected in 16 S rRNA gene. Of note, acquired tetracycline resistant gene(i.e. tetB gene) was first reported in Treponema pallidum.Conclusion: Tet B gene, as well as 16 S rRNA gene, may be related to the potential resistance to tetracyclines in treponema pallidum, and related surveillance study should be done further to avoid the occurrence of tetracyclines resistance in T. pallidum.