Antimicrobial resistance profiles of Escherichia coli isolated from laying hens in Zambia: implications and significance on one health.

BACKGROUND: Antimicrobial resistance (AMR) has been deepening in the layer poultry sector in Zambia partly due to the inappropriate use of antimicrobials. Escherichia coli (E. coli), a commensal and zoonotic bacterium, can potentially be a source of AMR. OBJECTIVES: This study assessed the phenotypic AMR profiles of E. coli isolated from the apparent health-laying hens in Lusaka and Copperbelt provinces of Zambia. METHODS: A cross-sectional study was conducted between September 2020 and April 2021 in which 365 cloacal swabs were collected from 77-layer farms based in Lusaka and Copperbelt provinces of Zambia. E. coli isolation and identification were done using cultural and biochemical properties and confirmed using the 16S rRNA gene sequencing. Antimicrobial susceptibility testing (AST) was done using the Kirby-Bauer disc-diffusion method. Data analysis was done using WHONET 2020 and Stata v.16.1. RESULTS: Of the 365 samples, E. coli was isolated from 92.9% (n = 339). The AMR was detected in 96.5% (n = 327) of the isolates, of which 64.6% (n = 219) were multidrug-resistant (MDR). E. coli was highly resistant to tetracycline (54.6%) and ampicillin (54%) but showed low resistance to meropenem (0.9%), ceftazidime (6.2%) and chloramphenicol (8.8%). CONCLUSION: This study found a high prevalence of E. coli resistant to some commonly used antibiotics in poultry, which is a public health concern because of the potential contamination of eggs and layers of chicken meat that enter the food chain. Urgent attention is needed, including strengthening antimicrobial stewardship and surveillance programmes in layer poultry production in Zambia

Identification of <i>Escherichia coli</i> and Related Enterobacteriaceae and Examination of Their Phenotypic Antimicrobial Resistance Patterns: A Pilot Study at A Wildlife–Livestock Interface in Lusaka, Zambia

A cross-sectional study was used to identify and assess prevalence and phenotypic antimicrobial resistance (AMR) profiles of Escherichia coli and other enterobacteria isolated from healthy wildlife and livestock cohabiting at a 10,000 acres game ranch near Lusaka, Zambia. Purposive sampling was used to select wildlife and livestock based on similarities in behavior, grazing habits and close interactions with humans. Isolates (n = 66) from fecal samples collected between April and August 2018 (n = 84) were examined following modified protocols for bacteria isolation, biochemical identification, molecular detection, phylogenetic analysis, and antimicrobial susceptibility testing by disc diffusion method. Data were analyzed using R software, Genetyx ver.12 and Mega 6. Using Applied Profile Index 20E kit for biochemical identification, polymerase chain reaction assay and sequencing, sixty-six isolates were identified to species level, of which Escherichia coli (72.7%, 48/66), E. fergusonii (1.5%, 1/66), Shigella sonnei (22.7%, 14/66), Sh. flexinerri (1.5%, 1/66) and Enterobacteriaceae bacterium (1.5%, 1/66), and their relationships were illustrated in a phylogenetic tree. Phenotypic antimicrobial resistance or intermediate sensitivity expression to at least one antimicrobial agent was detected in 89.6% of the E. coli, and 73.3% of the Shigella isolates. The E. coli isolates exhibited the highest resistance rates to ampicillin (27%), ceftazidime (14.3%), cefotaxime (9.5%), and kanamycin (9.5%). Multidrug resistance (MDR) was detected in 18.8% of E. coli isolates while only 13.3% Shigella isolates showed MDR. The MDR was detected among isolates from impala and ostrich (wild animals in which no antimicrobial treatment was used), and in isolates from cattle, pigs, and goats (domesticated animals). This study indicates the possible transmission of drug-resistant microorganisms between animals cohabiting at the wildlife–livestock interface. It emphasizes the need for further investigation of the role of wildlife in the development and transmission of AMR, which is an issue of global concern