Prevalence and molecular susceptibility of Mycoplasma genitalium in KwaZulu-Natal population.

Abstract

Background: Mycoplasma genitalium is a recently classified sexually transmitted pathogen associated with causing urethritis and cervicitis, potentially causing reproductive complications. Mycoplasma genitalium has been shown to develop resistance to the currently recommended drug regimens, namely, azithromycin used as first-line therapy and moxifloxacin (second-line). The resistance prevalence of M. genitalium to the current treatment is diverse across the world. In South Africa, few studies have evaluated the prevalence of resistance to azithromycin and other fluoroquinolones. This study was conducted to evaluate the presence of macrolide and fluoroquinolone-resistant gene mutations in a KwaZulu-Natal population infected with M. genitalium. Methods: Samples from the CAPRISA HIPPS cohort study were used for this analysis. Deoxyribonucleic acid was extracted from 100 stored M. genitalium positive self-collected vaginal swab samples. Real-time PCR was performed to confirm M. genitalium positivity. Genes associated with resistance to macrolides (23S rRNA, L4, L22) and fluoroquinolones (gryA) were sequenced and analysed. Results: All 100 samples were confirmed genotypically to be M. genitalium positive and were sequenced. From the 100 samples tested for M. genitalium, 73 were successful for 23S rRNA, 99 for L4, 91 for L22, and 80 for gryA. Of the seventy-three 23S rRNA sequences, five samples carried mutations associated with macrolide resistance. A total of 12 mutations coding for macrolide resistance (5 for 23S, 4 for L4, and 3 for L22) were identified following sequencing. The prevalence of resistance mutations to macrolides was thus 7% (5 of 73) for 23 S rRNA, 4% (4of 99) for L4, and 3% (3 of 91) for L22 protein. In the five samples that harboured 23S rRNA gene mutation one had: A2071T, A2072C, A2072T, and two with A2072G mutation. L4 and L22 harboured silent mutations at positions: T327C, G429A, C438T, C438A, G81A, and C351T. In the 80 samples successful for gryA, six carried mutations with a prevalence of 8% (6/80 x100%). Conclusion: Ongoing antimicrobial surveillance needs to be performed in our local populations as in our study we have seen the presence of mutations to macrolides and fluoroquinolones. This study was performed on samples collected during the early stages of introducing azithromycin as the first-line regimen for M. genitalium infection. More current studies need to be performed at a later time point to evaluate the antimicrobial resistance burden in M. genitalium.