Molecular investigation of antibiotic resistant bacterial strains isolated from wastewater streams in Pakistan

Antibiotic resistance is a global public health issue and it is even more daunting in developing countries. The main objective of present study was to investigate molecular responses of antibiotic-resistant bacteria. The 48 bacterial strains, which were previously isolated and identified were subjected to disc diffusion and MIC (minimum inhibitory concentration) determination, followed by investigating the production of the three beta-lactamases (ESBLs (Extended-spectrum Beta-lactamases), MBLs (Metallo Beta-lactamases), AmpCs) and exploring prevalence of the two antibiotic-resistant genes (ARGs); blaTEMand qnrS. Higher MIC values were observed for penicillin(s) than that for fluoroquinolones (ampicillin > amoxicillin > ofloxacin > ciprofloxacin > levofloxacin). Resistance rates were high (58–89%) for all of the tested beta-lactams. Among the tested strains, 5 were ESBL producers (4 Aeromonasspp. and 1 Escherichiasp.), 2 were MBL producers (1 Stenotrophomonassp. and 1 Citrobactersp.) and 3 were AmpC producers (2 Pseudomonasspp. and 1 Morganellasp.). The ARGs qnrS2and blaTEMwere detected in Aeromonasspp. and Escherichiasp. The results highlighted the role of Aeromonasas a vector. The study reports bacteria of multidrug resistance nature in the wastewater environment of Pakistan, which harbor ARGs of clinical relevance and could present a public health concern.