Fecal sludge and adjacent drinking water as reservoirs of multidrug resistant ESBL-producing pathogenic Escherichia coli in Rohingya Camps, Bangladesh

Fecal Sludge (FS) is a well-known reservoir for multiple pathogenic organisms and antimicrobial-resistant E. coli . Contaminated drinking water (DW) is the primary route through which fecal-oral diseases are spread. This study examined the prevalence of Extended-spectrum beta-lactamase (ESBL)-producing E. coli in FS and adjacent DW samples collected within the Rohingya Camps. The DW and treated FS samples were screened for thermotolerant E. coli and the isolates were characterized for their ESBL-production ability, presence of major antibiotic resistance (AMR) genes, pathogenic genes, biofilm formation ability and phylogenetic clustering. Among the samples, 88.1% FS and 40.2% DW contained E. coli . From the selected isolates, 32.3% of FS and 12.5% of DW were ESBL-positive. Subsequently, 113 ESBL-FS and 56 ESBL-DW isolates were characterized based on their concurrent presence. Upon screening, bla CTX−M (81.1%) was the most prevalent AMR gene, followed by bla TEM (23.7%) and bla NDM−1 (14.8%). Enteroaggregative E. coli (EAEC) (17.2%) and enterotoxigenic E. coli (ETEC) (12.4%) were the most prevalent diarrheagenic pathotypes and 4.7% were extra-intestinal pathogenic E. coli (ExPEC) strains. Antimicrobial susceptibility testing (AST) revealed that 98.2% of isolates were multidrug-resistant. At 25 °C, 34.3% of isolates formed strong biofilm. The ERIC (Enterobacterial Repetitive Intergenic Consensus sequences) phylogenetic clustering generated 16 clusters at a 70% similarity index. The detection of pathogenic isolates highlights the risk of severe infections within susceptible populations and a high percentage of multidrug resistance limits the treatment options.