Characteristics of Pathogenic Escherichia coli Associated with Diarrhea in Children under Five Years in Northwestern Ethiopia

Abstract

Diarrheagenic Escherichia coli (DEC) are the leading cause of infectious diarrhea and pose a significant global, regional, and national burden of disease. This study aimed to investigate the prevalence of six DEC pathotypes in children with diarrhea and determine their antibiotic resistance patterns. Samples from 107 diarrheagenic children were collected and processed for Escherichia coli (E. coli). Single-plex PCR was used to detect target virulence genes as well as characterize and categorize DEC pathotypes. Antibiotic resistance patterns were determined by the Kirby-Bauer disk diffusion method. E. coli was detected in 79 diarrheal stool samples, accounting for 73.8% of the samples collected. Additionally, 49.4% (39 out of 79) of the isolates harbored various typical virulence factors. Results revealed six pathotypes of virulence: enterotoxigenic E. coli (ETEC) (53.8%), enteropathogenic E. coli (EPEC) (12.8%), enteroaggregative E. coli (EAEC) (10.3%), Heteropathotypes (7.8%), Shiga toxin-producing E. coli (STEC), and enterohemorrhagic E. coli (EHEC) (7.7% each). The isolates exhibited high antibiotic resistance against trimethoprim/sulfamethoxazole (82.1%), amoxicillin (79.5%), ampicillin (74.4%), gentamicin (69.2%), and streptomycin (64.1%). An overall occurrence of 84.6% of multiple-drug resistance was observed in the isolates, with resistance ranging from three to four antibiotic classes. Our findings revealed a high level of pathogenic E. coli that were highly resistant to multiple categories of antibiotics among children in the Awi zone. These findings highlight the potential role of pathogenic E. coli in childhood diarrhea in tropical low-resource settings and underscore the need for continued research on the characteristics of pathogenic and antibiotic-resistant strains.

Keywords: Awi zone; children; diarrheagenic Escherichia coli; resistance; virulent genes.

Figure 1

Map of the study area. The map was created by using Esri’s ArcGIS^® 10.8 desktop GIS software.

Figure 2

Frequency of virulent genes and diarrheagenic E. coli pathotypes detected in children with diarrhea and hospitals. IGH: Injibara General Hospital, DPH: Dangila Primary Hospital, AGPH: Agew Gimjabet Primary Hospital, eae: attaching–effacing gene, stx2: Shiga-like toxin II gene, hlyA: E. coli hemolysin gene, aatA: aggregative adherence gene, lt: heat-liable toxin gene, st: heat-stable toxin gene.

Figure 3

Heat map showing the distribution of antimicrobial susceptibility and virulence profiles in 39 pathogenic E. coli isolates exhibited from samples of diarrheic children. CIP: ciprofloxacin, NAL: nalidixic acid, AMX: amoxicillin, AMP: ampicillin, GEN: gentamicin, STR: streptomycin, TMP: trimethoprim, TMP/SMX: trimethoprim/sulfamethoxazole, CTX: cefotaxime, TET: tetracycline, eae: attaching–effacing gene, stx2: Shiga-like toxin II gene, hlyA: E. coli hemolysin gene, aatA: aggregative adherence gene, lt: heat-liable toxin gene, st: heat-stable toxin gene.