Detection and characterisation of mycoplasmas in women visiting an antenatal or reproductive biology clinic

Abstract

Genital mycoplasmas are opportunistic bacteria that are associated with undesirable gynaecologic and reproductive events. These bacteria are characterised by their small size, lack of cell wall, extremely fastidious in vitro environmental requirements, and tendency to form centred colonies on solid media. Ureaplasmas and M. hominis are considered opportunistic pathogens because they can be isolated from the lower urogenital tract of healthy women as well as from individuals with disease. The commercial Mycofast Revolution assay permits the phenotypic detection and identification of genital mycoplasmas. This assay allows for antimicrobial susceptibility testing with specific minimum inhibitory concentrations (MICs) as defined by the 2011 Clinical and Laboratory Standards Institute (CLSI) guidelines. The antibiotics that are tested include clindamycin, erythromycin, levofloxacin, moxifloxacin, and tetracycline (CLSI, 2011). The aim of this study was to detect genital mycoplasmas as well as their antimicrobial susceptibility profiles in women visiting an antenatal and the reproductive biology clinic of a tertiary academic hospital in Pretoria, South Africa. Methods: Women who attended either the antenatal or the reproductive biology clinic at an academic hospital in Pretoria, Gauteng South Africa, who met the inclusion criteria, were approached to participate in this study. Four self-collected vaginal swabs were obtained from each participant visiting the clinics who gave signed informed consent. The first swab was used to inoculate A7 Mycoplasma agar plates for culturing genital mycoplasmas. The second swab was used to perform Nugent scoring for diagnosing bacterial vaginosis. The third swab was used to inoculate the Mycofast Revolution assay for the identification, enumeration and antimicrobial susceptibility profiles of genital mycoplasmas and the fourth swab was used for a molecular conventional PCR assay for the detection of genital mycoplasmas. Results: Hundred and six participants who either attended the antenatal (55) or reproductive biology clinic (51) at an academic hospital in Pretoria, Gauteng South Africa were recruited.In the reproductive biology clinic, 53% (27/51) of cultures were positive for Ureaplasma spp., and 18% (9/51) for M. hominis. Ureaplasma spp. resistant to tetracycline in the antenatal and the reproductive biology clinics were 51% (18/35) and 52% (14/27) respectively. Bacterial vaginosis was diagnosed using the Nugent scoring system and 20% (11/55) of the participants were BV positive in the antenatal clinic and 20% (10/51) in the reproductive biology clinic. The Mycofast Revolution assay detected genital mycoplasmas in 67% (37/55) of samples at the antenatal clinic and 57% (29/51) in the reproductive biology clinic. In the antenatal clinic, 64% (35/55) of cultures were positive for Ureaplasma spp., and 27% (15/55) for M. hominis. The overall prevalence of M. genitalium, M. hominis, U. parvum and U. urealyticum in both clinics combined detected using conventional multiplex PCR assay was 1% (1/106), 5% (5/106),19% (20/106) and 4% (4/106) respectively. Mycoplasma hominis resistance to tetracycline in the antenatal and the reproductive biology clinics was 56% (5/9) and 51% (18/35) respectively. Conclusion: This study has shown that the infection rate of genital mycoplasmas was higher among pregnant women. In order to prevent complications in pregnant women, the foetus and the neonate, routine screening for the presence of genital mycoplasmas is strongly recommended. This study has shown that the Mycofast Revolution assay could be considered as a cost-effective alternative to conventional culture methods for the rapid detection of genital mycoplasmas as well as antibiotic resistance.