High prevalence of co-trimoxazole and carbapenem resistance among uropathogenic bacteria from a community hospital in New Delhi, India.

BACKGROUND: Urinary tract infections (UTI) caused by multidrug-resistant bacteria are a serious concern worldwide. The problem is exacerbated by the rapid rise of resistance to antibiotics, including co-trimoxazole and carbapenem. This study investigates the prevalence of co-trimoxazole and carbapenem resistance among bacteria causing UTI from a community hospital in New Delhi. METHODS: Antibiotic susceptibility tests were carried out by Kirby-Bauer disc diffusion and broth microdilution method. Molecular detection of antibiotic-resistant genes was done by PCR. Plasmid-mediated horizontal gene transfer and biofilm studies were performed by conjugation assay and crystal violet assay, respectively. FINDINGS: Phenotypic screening of 141 non-duplicate bacterial isolates obtained from urine samples showed co-trimoxazole resistance in 72% isolates (n = 101). Among 101 co-trimoxazole resistant isolates, 63 were phenotypically positive for carbapenem resistance. The isolates were identified as Escherichia coli (n = 69), Klebsiella pneumoniae (n = 15), Streptococcus dysgalactiae (n = 5), Citrobacter spp. (n = 3), Pseudomonas aeruginosa (n = 3), Staphylococcus aureus (n = 3), Klebsiella oxytoca (n = 1), Serratia fonticola (n = 1) and Proteus mirabilis (n = 1). Co-trimoxazole resistant genes sul1, sul2, dfrA1, dfrA5, dfrA7, dfrA12, and dfrA17 were detected in 75, 28, 29, 23, 60, 63, and 8 isolates, respectively. Carbapenem resistance genes blaNDM, blaOXA-48, blaKPC, and blaIMP were amplified in 36, 77, 8, and 27 isolates, respectively using plasmid DNA as the template. CONCLUSION: This study provides useful data on an alarming rise in co-trimoxazole and carbapenem resistance among bacteria causing UTI. Conjugation assay confirmed horizontal transfer of plasmid-borne resistance genes. Furthermore, some of these isolates were resistant to nitrofurantoin and fosfomycin, the last resort antibiotics for treating UTI.