Emergence of β-lactamase-producing Proteus mirabilis in clinical settings: A genotypic investigation of resistance mechanisms and carbapenemase genes blaNDM-1 and blaKPC-2

Abstract

Proteus mirabilis, an opportunistic pathogen frequently implicated in urinary and wound infections, has shown increasing multidrug resistance, posing significant therapeutic challenges. The study aims to investigate the prevalence and distribution of β-lactam resistance in P. mirabilis clinical isolates through the genotypic detection of the bla_KPC-2 and bla_NDM-1 genes. This study analyzed 100 clinical isolates of P. mirabilis obtained from various clinical specimens over a period of 10 months. Isolates were identified through standard microbiological techniques, including Gram staining, culture characteristics, and biochemical profiling. The majority of isolates (46 %) were recovered from patients aged 61–75 years, with a male predominance (65 %). Pus samples accounted for the highest number of isolates (59 %), predominantly associated with diabetic foot ulcers, cellulitis, and gangrene. Antimicrobial susceptibility testing using Vitek (bioMérieux) showed that 33.31 % of isolates were resistant to commonly used antibiotics, with the highest resistance noted against ciprofloxacin (58 %), ceftazidime (50 %), and cotrimoxazole (49 %). However, piperacillin-tazobactam (96 %), Fosfomycin (94 %), and ertapenem (87 %) remained largely effective. Multidrug resistance was observed in 83 % of isolates, with 18 % showing resistance to six antibiotic classes. Molecular characterization showed that 19 % of isolates harbored the bla_NDM-1 gene, 8 % carried bla_KPC-2, and 4 % co-harbored both, indicating carbapenemase production. These findings underscore the urgent need for continuous surveillance, strict infection control measures, and prudent antibiotic use to curb the emergence and spread of resistant P. mirabilis strains in clinical settings.