Isolation and Identification of Organisms Associated with Bacterial vaginosis in Pregnant Women with per Vaginal Discharge. A one year Cross Sectional Study

Abstract

Background and Objectives : Bacterial Vaginosis ( BV) is one of the important causes of vaginal discharge among women of child bearing age. It is also a risk factor for premature rupture of membranes ( PROM ) , prematurity, chorioamnionitis, postpartum endometritis and delivery of low birth weight babies etc 1 . Objectives of the study : 1. To diagnose BV by two noncultural methods ( Amsel’s criteria and Nugent’s Scoring and Grading of Gram stained smears ) and to compare them. 2. To isolate and identify aerobic and anaerobic organisms associated with per vaginal discharge. Materials and Methods : Samples were collected from 120 pregnant women complaining of vaginal discharge attending the OBG Out Patient Department of KLE’S Dr. Prabhakar Kore Hospital and MRC., Belgaum. Three high vaginal swabs were collected from the posterior fornix of the vagina, two were collected in 0.5ml of saline and one in 2ml of Thioglycollate medium. BV was diagnosed according to the Clinical Composite Criteria ( Amsel’s criteria ) if at least three out of the following four criteria were met 2 . ( 1) .A thin homogenous white discharge, ( 2) vaginal pH of more than 4.5, ( 3) a positive Amine test, and ( 4) presence of clue cells on wet mount. According to Nugent’s method XI 1 , the Gram stained smears of vaginal discharge were scored and graded as BV if the score was more than 7.The organisms associated with vaginal discharge were isolated and identified according to standard microbiological methods incubating Columbia Blood Agar ( CBA) plates in CO further identified by following standard methods 4 . 3 . G.vaginalis was cultured by 2 jar and isolates were Results : BV was diagnosed in 51 ( 42.5% ) cases according to Clinical Composite Criteria ( Amsel’s ) and in 42 ( 35% ) cases by Nugent’s Scoring and Grading of Gram stained vaginal smears. Using Gram’s staining as standard, sensitivity, specificity, positive predictive value and negative predictive value of Amsel’s criteria was 78.5%, 76.9%, 64.7% and 86.9% respectively. Culture was positive in 40 ( 95.2% ) cases among BV ( diagnosed by Nugent’s method) and 13 ( 27.6% ) NBV cases. Bacteroides fragilis ( B.fragilis ) was the most common anaerobic bacteria isolated followed by Prevotella melaninogenica ( P. melaninogenica ) and G. vaginalis was the most common aerobe isolated. Conclusion :The present study showed moderate agreement between the two non cultural methods ( Amsel’s criteria and Nugent’s method) . Polymicrobial mixed isolates were significantly raised in BV as compared to NBV cases.