Comparative Analysis of E. coli Resistome of Mother and Infants from a Birth Cohort in The Dzimauli Community, Limpopo Province, South Africa

Abstract

Background: Escherichia coli is a Gram-negative, commensal bacterium that colonises the gastrointestinal tract of human infants within a few hours of birth and coexists with the host for a lifetime. However, some strains of E. coli may carry antibiotic resistance genes, forming the resistome. Infants may be exposed to potentially antibiotic-resistant microorganisms and antimicrobial resistance genes during birth; nevertheless, the development and composition of the gut resistome in early life remain poorly understood. Therefore, the present study aims to compare the E. coli resistomes of mothers and infants to determine whether infants acquire the resistome from their mothers. Methods: Sixty-two mother-infant pairs were recruited from seven villages in the Dzimauli community, Vhembe District. Stool samples were collected from both the mother and child at baseline. Escherichia coli was isolated from each sample and subjected to DNA extraction. Multiplex PCR was performed for E. coli pathotyping. Antimicrobial Susceptibility Testing was conducted following the Kirby-Bauer disc diffusion method for phenotypic resistance profiling, and Whole-genome sequencing was performed to identify ARGs in E. coli isolates. Results: Infants showed higher resistance to most antibiotics than mothers, with resistance to CTX at 74.5% and 62.7%, and to CPM at 66.7% and 56.9%, respectively. Infant resistance was not entirely associated with factors such as infant diet, sex, birth age, and others. Infants had more resistance genes than mothers, with blaTEM-1B being identified in all mother and infant isolates. Conclusion: Mothers and infants may share similar phenotypic and genotypic resistance profiles; however, the infant resistance may not entirely depend on the maternal resistome. CHAP