Characterizing the co-existence of metallo-β-lactamase-producing and extended-spectrum β-lactamase-producing <i>Escherichia coli</i> and <i>Klebsiella pneumoniae</i> isolates in community wastewater samples of Dhaka, Bangladesh

<i>Escherichia coli</i> and <i>Klebsiella pneumoniae</i> isolates with multiple antibiotic-resistance genes in wastewater pose serious public health risks, as they can potentially contaminate the food and water supply. The main aim of this study was to isolate and identify <i>E. coli</i> and <i>K. pneumoniae</i> from community wastewater samples, and determine their antibiotic-resistance profiles and their antibiotic-resistant genes. From the northern part of Dhaka, Bangladesh, 36 wastewater samples were collected across 11 different areas, which were then serially diluted, and cultured using selective media. Isolates were identified via polymerase chain reaction. Out of the 197 isolates identified, <i>E. coli</i> and <i>K. pneumoniae</i> accounted for 55.8% (<i>n</i> = 110) and 44.2% (<i>n</i> = 87), respectively. Antibiotic susceptibility tests revealed multidrug resistance (MDR) in 30% of <i>E. coli</i> and 35.56% of <i>K. pneumoniae</i> isolates. Among <i>E. coli</i>, the prevalence of antibiotic-resistance genes included <i>bla</i>_NDM-1 (8.9%), <i>bla</i>_SHV (13.9%), and <i>bla</i>_CTX-M (7.6%). In <i>K. pneumoniae</i>, the percentages were <i>bla</i>_NDM-1 (12.8%), <i>bla</i>_SHV (4.3%), and <i>bla</i>_CTX-M (5.0%). Co-existence of multiple antibiotic-resistance genes was observed in 4.54% of <i>E. coli</i> isolates (<i>n</i> = 5) and 5.74% of <i>K. pneumoniae</i> isolates (<i>n</i> = 5). This suggests the escalating issue of infectious species becoming increasingly resistant to antibiotics in wastewater systems.