Plasmid-mediated antibiotic resistance among uropathogens in primigravid women-Hyderabad, India.

Abstract

With the growing threat of antimicrobial resistance worldwide, uncovering the molecular epidemiology is critical for understanding what is driving this crisis. We aimed to evaluate the prevalence of plasmid-mediated-quinolone-resistance (PMQR) and extended-spectrum beta-lactamase- (ESBL) producing gram-negative organisms among primigravid women with bacteriuria. We collected urine specimens from primigravid women attending their first antenatal visit at Gandhi Hospital during October 1, 2015 to September 30, 2016. We determined antimicrobial susceptibility and ESBL and quinolone resistance using VITEK-2. We performed polymerase chain reaction amplification on resistant isolates for detection of ESBL-encoding genes (TEM, SHV, CTX-M) and PMQR genes (qnrA, qnrB, qnrD, qnrS, aac (6')-Ib-cr). Of 1,841 urine samples, 133 demonstrated significant bacterial growth with gram-negative bacilli accounting for 85% of isolates, including Escherichia coli (n = 79), Klebsiella pneumoniae (n = 29), Sphingomonas (n = 3), Enterobacter (n = 1), and Citrobacter (n = 1). We found 65% of E. coli isolates and 41% of K. pneumoniae isolates were ESBL positive. Of ESBL-positive isolates, the most common genes conferring resistance were TEM-1 (66.7%) followed by CTX-M-15 (33.3%). Fifty-seven percent of ESBL-positive E. coli also demonstrated resistance to quinolones with the most common PMQR genes being qnr-S (62.5%) and aac (6')-Ib-cr (37.5%). We did not find any resistance to quinolones among ESBL-positive K. pneumoniae isolates. Across different classes of antibiotics we found a strong clustering of multi-drug resistance in E. coli with over 45% of ESBL-positive isolates demonstrating resistance to at least three classes of antibiotics. This study emphasizes the high prevalence of plasmid-mediated ESBL and quinolone resistance in community-acquired urinary tract infections of primigravid women. The overall abundance of multi-drug-resistant isolates in this population is alarming and may present therapeutic challenges.