Laboratory Diagnosis of Bacterial Vaginosis and Potential Pathogens Other Than Group B Streptococcus in Vaginal Swab of Pregnant Women in Dhaka Medical College Hospital.

Pathogenic microorganisms are important cause of maternal and neonatal infections which are transmitted from colonized vagina of mother. The purpose of the present study was to detect the potential pathogens other than Group B Streptococcus in vaginal swab of pregnant women. This prospective cross sectional study was conducted from July 2013 to June 2014 at Dhaka Medical College Hospital, Dhaka, Bangladesh. A total of 224 vaginal swab samples were studied. Gram stain Nugent score was applied for all vaginal smear to detect bacterial vaginosis. Organisms were isolated and identified by wet film microscopy, Gram stain, biochemical tests, culture and PCR. Toxic shock syndrome toxin-1 gene and drug resistance genes such as mecA, vanA, vanB were detected among isolated Staphylococcus aureus. Antimicrobial susceptibility was done by disc diffusion method. Double disc synergy test was used to detect ESBL (Extended spectrum beta lactamases) producers. MIC (Minimum inhibitory concentration) of oxacillin and vancomycin were done for Staphylococcus aureus to detect MRSA (Methicillin resistant Staphylococcus aureus) and VRSA (Vancomycin resistant Staphylococcus aureus). Of the 224 samples, 44(19.64%) were Staphylococcus aureus, 22(9.8%) were Escherichia coli. Bacterial vaginosis was found in 12(5.36%) cases. Among the 9(21.43%) phenotypically identified ESBL producers, 4(18.18%) were Escherichia coli, 2(25%) were Klebsiella pneumoniae. Ninety six percent and 91% of the Escherichia coli were sensitive to colistin and imipenem. All the Klebsiella spp. was sensitive to colistin and all the Proteus spp. and the Pseudomonas aeruginosa were sensitive to imipenem and colistin. Of the 44 Staphylococcus aureus, 5(11.36%) were MRSA, 2(4.54%) were VRSA, 2MRSA were PVL gene positive and 2(4.54%) were positive for TSST-1 gene by PCR. All the isolated MRSA and VRSA were sensitive to linezolid. One of the two VRSA strains had MIC of vancomycin 64μg/ml and another had 128μg/ml. VRSA strains were positive for vanB gene, no VRSA was positive for vanA gene. Vaginal ecosystem study with the detection of pathogens can be helpful in the prevention of preterm delivery, premature rupture of membrane, chorioamnionitis, neonatal, puerperal and maternal-fetal infections.