Prevalence and susceptibility of BV-associated Gardnerella vaginalis biotypes in a cohort of pregnant women attending antenatal clinics in the Western Cape
Jooste-Vraagom V, Arendse M, Abrantes P, Africa CWJ. Department of Medical Biosciences, University of the Western Cape, Robert Sobukwe Road, Bellville, Western Cape
Introduction: Bacterial vaginosis (BV) is characterized by a characteristic discharge, increased vaginal pH, squamous vaginal epithelia with granular borders, called 'clue cells'.and a reduction in Lactobacillus species. BV has repeatedly been associated with adverse pregnancy outcomes, including preterm delivery, late miscarriage and premature rupture of membranes, infection of the chorion, amnion, amniotic fluid and pelvic inflammatory disease
Objectives: This study sought to detect the prevalence of BV and the antimicrobial susceptibility of Gardnerella vaginalis in a cohort of pregnant women in the Western Cape.
Materials and Methods: Vaginal samples were collected without a speculum using a sterile cotton swab and transported to the laboratory in Amies media with charcoal (18114CST, Sterlin) Vaginal swabs were processed within 2 hours of sampling and microscopically scored according to Nugent criteria (Nugent et al, 1991). The presence of G. vaginalis was determined by culture on enriched media incubated anaerobically for 48-72 Hours at 37°C. Susceptibility of G. vaginalis to metronidazole and clindamycin were determined using disc-diffusion.
Results: Gram stain analysis of vaginal swabs revealed that 32% of the study population harboured vaginal flora indicative of BV, with G. vaginalis resistance to metronidazole observed in 49% of BV cases.
Discussion: Nugent scoring showed good specificity and sensitivity in diagnosing BV with metronidazole-resistant G. vaginalis biotype 7 most frequently detected. References:
Nugent R. P, Krohn M. A, Hiller S. L. reliability of diagnosing bacterial vaginosis is improved by a standardized method of Gram stain interpretation. Journal of Clinical Microbiology. 1991; 29 (2): 297-301.