Predominance of Multidrug Resistant Escherichia coli of Environmental Phylotype in Different Environments of Dhaka, Bangladesh

Abstract

Considering the ecological diversity of <i>E. coli</i>, the main aim of this study was to determine the prevalence, phylogroup diversity, and antimicrobial susceptibility of <i>E. coli</i> isolated from 383 different clinical and environmental sources. In total, varied prevalence was observed of the 197 confirmed <i>E. coli</i> that were isolated (human-100%, animal-67.5%, prawn-49.23%, soil-30.58%, and water-27.88%). Of these isolates, 70 (36%) were multidrug-resistant (MDR). MDR <i>E. coli</i> was significantly associated with their sources (χ² = 29.853, <i>p</i> = 0.001). Humans (51.67%) and animals (51.85%) carried more MDR <i>E. coli</i> than other environments. The <i>eae</i> gene indicative of recent fecal contamination was not detected in any isolate, indicating that these <i>E. coli</i> isolates could be present in these environments for a long time and became naturalized. Phylogroup B1 (48.22%) was the predominant group, being present in all hosts analyzed and with the commensal <i>E. coli</i> group A (26.9%) representing the second predominant group. According to chi-square analysis, phylogroup B1 was significantly associated with <i>E. coli</i> from humans (<i>p</i> = 0.024), soil (<i>p</i> < 0.001) and prawn samples (<i>p</i> < 0.001). Human samples were significantly associated with phylogroup B1 (<i>p</i> = 0.024), D (<i>p</i> < 0.001), and F (<i>p</i> = 0.016) of <i>E. coli</i> strains, whereas phylogroup A (<i>p</i> < 0.001), C (<i>p</i> < 0.001), and E (<i>p</i> = 0.015) were associated with animal samples. Correspondence analysis results also indicated the association of these phylogroups with their hosts/sources. The findings of this study exhibited a non-random distribution of phylogenetic groups, though the diversity index was highest for human <i>E. coli</i> phylogroups.