Vaginal Colonization and Susceptibility to Antibiotics of Enterococci During Late Pregnancy in Kerman City, Iran

Enterococci are a natural part of the genito-intestinal and gastrointestinal normal flora in humans and are widely distributed in the environment and are one of the most important causes of nosocomial infections. The aim of this study was to identify Enterococcus spp. from vaginal samples of pregnant women and measure their antibiotic resistance patterns. This descriptive study was performed on 602 strains. Vaginal swabs were cultured for Enterococcus spp. from pregnant women at 35 - 37 weeks of pregnancy in Kerman city, Iran, during April 2013 to March 2014 or in labor samples transported to the laboratory using Amies transport medium. Swabs were cultivated in Todd Hewitt broth medium and subsequently plated on blood agar plates containing gentamicin and nalidixic acid. Antimicrobial susceptibility testing was performed for enterococci by disk diffusion and minimum inhibitory concentrations (MIC). Vaginal colonization of Enterococcus genus was 8.14%. Parameters of age, parity, history of abortion, history of ruptured membranes, vaginal discharge and other vaginal signs (itching and so on) had no influence on vaginal colonization of Enterococcus spp. The predominant species were respectively E. faecalis 89.8%, E. faecium 6.1% and other Enterococcus spp. 4.1%. All samples were susceptible to gentamicin and amoxicillin and MIC for gentamicin and amoxicillin was 2 to 8 μg mL-1 and 0.5 to 8 μg mL-1, respectively. Resistance to ciprofloxacin was 6.4%, while its MIC range was 8 to 16 μg mL-1. In this study none of the isolates were resistant to vancomycin, while 20% of isolates with MIC of 4 μg mL-1 had intermediate reaction to it. Other demographic parameters had not correlation with vaginal colonization of enterococci.