Broad-spectrum antibiotic resistance in Klebsiella pneumoniae isolates from Mula-Mutha River (Pune, India) and the role of heavy metals and associated human health risks

The current study has been performed to (a) isolate Klebsiella pneumoniae from the river flowing through Pune City, India, (b) investigate the wide-spectrum antibiotic resistance (ABR), and underlying resistance determinants, (c) evaluate the correlation between multidrug-resistant (MDR) strains and heavy metals, and (d) associated health risk assessments. Water samples were collected from the six sites and analyzed for pH, electrical conductivity (EC), temperature, and heavy metal (Zn, Cu, Pb, Cd, and Co) concentrations. K. pneumoniae was isolated and screened for antibiotic resistance (ABR) profiling, extended-spectrum beta-lactamase (ESBL) production, biofilm formation, and efflux pump activity. The Spearman correlation analysis was performed to study the relationship between environmental factors and K. pneumoniae. Besides, a human health risk assessment model was used to evaluate the potential carcinogenic and noncarcinogenic risks of heavy metals in adults and children. Out of 36 isolates, 26 displayed MDR phenotypes including resistance against cephalosporins and the last-resort antibiotics. A total of 15.3% of isolates were confirmed to produce ESBL, whereas 73% of isolated strains could produce biofilms. Collected water from the same sites showed heavy metal (Zn > Pb > Cu > Cd > Co) levels with high pollution indices (HEIs) exceeding the BIS and WHO standards. Spearman correlation revealed a strong association between heavy metals (Pb, Cd, Zn, and Co) and MDR K. pneumoniae. A human health risk assessment showed that average daily doses (ADDs) of heavy metals posed significant carcinogenic and noncarcinogenic risks, especially in children. These findings shed light on the importance of the urgent need for improved water quality management and strategies to combat ABR. The strong correlation between heavy metal contamination and MDR K. pneumoniae suggests that environmental pollution plays a crucial role in ABR and exacerbates public health risks.