Abstract

Some species of lactobacilli are hydrogen peroxide (H₂O₂) producers which may have a protective effect against vaginal colonization by pathogenic species. The aim of this study was to investigate the lactobacillary flora in normal pregnant women and pregnant women with preterm labor, by smear and Nugent score and to assess the distribution of lactobacilli generating hydrogen peroxide in both groups and its correlation to preterm labor. Vaginal specimens were obtained from 60 normal pregnant women and 40 pregnant women with preterm labor with intact membranes. Leukocytic counts, pH detection and Nugent score were done. Isolation and semi-quantification of vaginal lactobacilli on Man-Rogosa-Sharp media (MRS) and then identification of lactobacilli by detection of 1,350 bp fragment of 16S rRNA gene by polymerase chain reaction (PCR) were done. Lactobacilli were finally tested for their production of hydrogen peroxide. Nugent score was significantly higher in women with preterm labor with intact membranes than normal pregnant women (P<0.001). There was significant high isolation of lactobacilli in normal pregnant women as it was isolated from 47(78.3%) normal pregnant women and from 15(37.5%) pregnant women with preterm labor with intact membranes (P<0.001). As regards hydrogen peroxide production from the isolated strains, there was a highly significant difference between both groups as after 30 min, hydrogen peroxide producing lactobacilli were isolated from 59.6% of normal pregnant women isolates and 20% of preterm labor women isolates (P<0.001). After 1 h, the percentage of isolation had increased to 72.5 and 30% in both groups, respectively. With regard to the pregnancy outcomes, the incidence of preterm delivery was significantly reduced in the strong positive group. Hydrogen peroxide production by vaginal lactobacilli may be used as a simple test for detection of women at high risk of preterm labor.

Key words: Lactobacilli , hydrogen peroxide, vaginal flora, pregnant women.