Article Text
Abstract
Background Antibiotic resistance in U. urealyticum (UUA), U. parvum (UPA) and M. hominis (MH) poses an increasing issue. However, data regarding antibiotic susceptibility is limited to several countries, whereas information about clonality is available only from China.
Methods We analysed 140 genital samples collected in two laboratories from unique patients in Bern during 2014. Identification and antimicrobial susceptibility tests were obtained using the mycoplasma IST 2 kit (bioMérieux) and sequencing of 16S rDNA. Clonality was analysed with multilocus sequence typing (MLST) and expanded MLST (eMLST), whereas quinolone and macrolide resistance were studied by sequencing gyrA/B, parC/E, as well as genes encoding 23S rRNA and L4/22 ribosomal proteins.
Results One-hundred-three samples (74%) were confirmed being positive for UUA/UPA, whereas 21 (15%) were positive for both UUA/UPA and MH. Non-susceptibility was highest to ciprofloxacin (19.4%) and ofloxacin (9.7%), whereas low rates were observed for clarithromycin (4.8%), erythromycin (1.9%), azithromycin and tetracycline (both <1%). Various Sequence Types (STs) previously reported in China (ST1, ST2, ST4, ST9, ST22, ST47), but also eight novel lineages, were detected. Only some quinolone-resistant isolates had amino acid substitutions in ParC (Ser83Leu in UPA) and ParE (Val417Thr in UPA and the novel Thr417Val in UUA), whereas the mechanism (s) for the remaining strains remains unclear. Although several isolates were non-susceptible to macrolides, mutations in 23S rRNA or substitutions in L4/L22 were not detected.
Conclusion This is the first study analysing susceptibility of Ureaplasma spp. isolates detected in Switzerland and the clonal distribution outside China. Resistance rates are low compared to other surrounding countries, but the empirical use of quinolones is compromised. We hypothesise that some hyperepidemic STs (e.g., ST4) spread worldwide via sexual intercourse. Large combined microbiological and clinical studies should address this important aspect.