Introduction: The vaginal flora is a complex microbial environment. The disruption of this niche usually leads to a pathological state and symptoms in patients. Aerobic vaginitis is a distinct form of vaginal inflammation, mainly caused by aerobic/facultative anaerobic bacteria (Staphylococcus aureus, Streptococcus agalactiae, and members of the Enterobacteriaceae). This study describes the prevalence and antibiotic susceptibility patterns of S. aureus isolated from vaginal samples from females at a tertiary-care teaching hospital in Hungary.
Methods: This retrospective study was carried out using data collected at the Albert Szent-Györgyi Clinical Center (University of Szeged) corresponding to a 10-year period (2008-2017). Antimicrobial susceptibility testing was performed using the disk diffusion method and gradient diffusion, using EUCAST interpretative standards. Methicillin-resistant S. aureus (MRSA) was detected on mannitol salt agar using cefoxitin disks, the PBP2' Latex Agglutination Test Kit, and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry.
Results: The median age of affected patients was 31 years. Most (93.95%) of the samples received were vaginal swabs. A total of 3,356 individual isolates were recorded (335.6 ± 89.10/year, range: 213-480 isolates). In 91.4% of samples, S. aureus was the only pathogen isolated. The highest levels of resistance were detected against erythromycin (11.11 ± 3.65%, range: 6.76-17.17%) and clindamycin (10.85 ± 3.36%, range: 6.49-15.54%), whereas resistance rates against doxycycline, ciprofloxacin, chloramphenicol, sulfamethoxazole-trimethoprim, and gentamicin were much lower (0-4.48%). Susceptibility to cefoxitin was observed in 97.79% of the isolates; 74 strains were MRSA. All MRSA strains were susceptible to the antibiotics used for therapy for multidrug-resistant Gram-positive infections.
Conclusions: A slow and steady increase in resistance levels could be observed (mainly corresponding to MRSA isolates). Although the present resistance trends are still advantageous (compared to European resistance levels) and do not hinder adequate therapy, continuous surveillance of resistance levels is recommended. Macrolides and clindamycin should be used with caution, and, if available, only when susceptibility to these drugs has been verified.