Exploring Genetic Variations and Plasmid Diversity in Escherichia coli strains Isolated from Tertiary Care Hospitals Located in Dhaka City, Bangladesh

The multidrug resistant (MDR) Escherichia coli, particularly beta-lactamase producing strains, has become a global health challenge, where wastewater systems, specially from hospitals, serve as critical reservoirs for the dissemination of resistance genes. The objectives of the study were to investigate the whole genome sequence diversity and genetic variations focusing on their evolutionary relationships, genetic similarity, and single nucleotide polymorphisms (SNPs) of pathogenic beta-lactamase producing E. coli strains. A total of four beta-lactamase producing E. coli strains, from differently located tertiary care hospitals, were included in this study. A heatmap of genetic similarity revealed near-identical genetic makeup among the strains. A number of genes like, AcrAB-TolC, beta-lactamase genes, and resistance genes of GlpT, gyrA, msbA, and tet (M) were found to be expressed in these strains. However, the presence of virulence genes of aerobactin synthesis gene (iucA, iutA) and type III secretion systems (espX1, espX4, espX5) in the strain ensured pathogenicity of the strains. These findings provide insights into the whole genome sequence diversity of E. coli in urban based tertiary care hospital wastewater, emphasizing the genetic variation and plasmid diversity in these E. coli strains, which may have implications in public health and microbial ecology of the environment.