Vaginal Carriage of Antibiotic Resistant Escherichia coli by Pregnant Women: A Concern for the Neonate

Background: We report the resistance pattern and plasmid profile of vaginal isolates of Escherichia coli isolated from asymptomatic pregnant women attending the outpatient department of a primary health care centre in a district of North east India.
Methodology: Antibiotic susceptibility was done by disc diffusion method and interpretation as sensitive, intermediate or resistant was done as per Clinical Laboratory Standards Institute’s interpretive standards for Enterobactereriaceae. E. coli ATCC 25922 was used as the control strain. Phenotypic screening for extendedspectrum beta-lactamase was done using the phenotypic disc confirmatory test. Plasmid DNA was extracted as per manufacturer’s instructions using commercially available kit. The plasmid band and size was estimated by comparison with a 1kb DNA marker.
Results: A total number of 40 E. coli isolates were obtained after screening 246 pregnant women. Reduced susceptibility to at least one antimicrobial was seen in 34 isolates (85%) of E. coli. Highest resistance was to cefotaxime (60%). Twelve isolates (30%) were found to be multidrug resistant (reduced susceptibility to antimicrobial drugs belonging to ≥3 classes). Seventeen (42.5%) isolates were ESBL producers of whom 9 were multidrug resistant (MDR). Plasmid DNA isolation was done for thirty seven of the isolates of whom 4 did not show any band. The number of plasmids varied from 1 to 5 per isolate. Plasmid size ranged from 1 kb to above 10 kb when compared to a 1 kb ladder.
Conclusion: This study demonstrates that drug resistant E. coli exists as colonizers in the genital tract of pregnant women.