β-lactamase and Plasmid-mediated Quinolone Resistance Determinants Among Proteus spp. Isolates at a Tertiary-care Hospital in Kolkata, India

Emerging antibiotic resistance (ABR) in Proteus spp., especially to third-generation cephalosporins (3GCc), carbapenems, and fluoroquinolones, challenges the treatment outcome and infection prevention. Limited studies pose a knowledge gap between them and ABR. We investigated the in vitro efficacy of therapeutic options and prevalence of β-lac-tamase and plasmid-mediated quinolone resistance (PMQR) traits in 3GC- and/or fluoroquino-lone-nonsusceptible Proteus (P.) spp. (n=27) in Kolkata, India, during 2021–2022. P. mirabilis was commonly isolated (>80%) from superficial and urine samples. The majority of the isolates (48-78%) remained susceptible to piperacillin-tazobactam, meropenem, amikacin, cefoperazone-sulbactam, and cefepime. All isolates showed >0.2 multiple-antibiotic resistance index, with >65% being multi-drug and >30% being extensively drug-resistant. blaTEM (n=9), blaNDM (n=9), and qnrA (n=6) were commonly noted with the co-production of β-lactamases and PMQR in ten (37%) isolates. More than 50% of the isolates were devoid of the tested acquired genes. The study concludes that superbugs dominate, with limited occurrence of plasmid-borne markers in this geographic location.