Objective: Salmonella species and Escherichia coli are major bacterial enteropathogens of worldwide public health importance that cause devastating foodborne diseases, thereby contributing to increased human morbidity and mortality. Both pathogens have also been found to contribute towards the spread of antimicrobial resistance through the food chain, especially in poultry. This study aimed to determine the occurrence of antibiotic-resistant Salmonella spp. and E. coli in broiler chickens at farm level, abattoirs, and open markets in selected districts of Zambia.Methods: A cross-sectional study was undertaken in seven districts of Zambia to determine the resistance profiles of Salmonella spp. and E. coli obtained from broiler chickens at farms, abattoirs, and open markets. A total of 470 samples were collected which include; litter, cloacal swabs, and carcass swabs. Samples were inoculated into buffered peptone water and incubated for 24 hours then sub-cultured onto MacConkey and Xylose Lysine Deoxycholate agar plates. Identification of Salmonella spp. and E. coli was done using the API-20E kit and confirmation by 16S rDNA sequencing. Confirmed isolates were tested against a panel of 09 antibiotics using the Kirby-Bauer disc diffusion method and interpreted according to the Clinical Laboratory Standards Institute guidelines. Data analysis of the antibiotic sensitivity test results was done using WHONET 2018 software.Results: Overall, 4 Salmonella spp. and 280 E. coli were isolated. One of the Salmonella spp. was resistant to ampicillin (25%), amoxicillin/clavulanic acid (25%), and cefotaxime (25%). E. coli antibiotic resistance was highest to tetracycline (81.4%) and 100% susceptibility to imipenem. The antibiotic susceptibility profile revealed 75.7% (237/280) multidrug-resistant (MDR). The highest MDR profile was observed in 8.2% (23/280) isolates in which 6 out of the 9 classes of antibiotics tested were resistant. Out of the 280 isolates, 11.4% (32/280) exhibited Extensive Drug resistance (XDR).Conclusion: The study found antimicrobial resistance to E. coli and Salmonella spp. in market-ready broiler chickens which were resistant to important antibiotics and is of public health concern.

The challenges posed by antibiotic-resistant pathogens have continued to increase worldwide, particularly in resource-limited countries. Human-livestock interactions are implicated in the complex AMR causal web. A cross-sectional study was conducted in four districts of Lusaka Province, Zambia to determine the antibiotic resistance patterns, ESBL production of E. coli isolated from stool samples of broiler poultry farm workers, and to assess poultry farmers' antibiotic resistance awareness. Sixty-six human stool samples were collected and processed for E. coli isolation, antibiotic resistance testing, and screened for ESBL production. In addition, 80 farmers were assessed for their level of awareness on antibiotic resistance. A total of 58 single E. coli isolates were obtained which showed high (87.9%) resistance to tetracycline, trimethoprim/sulfamethoxazole (48.3%), and ampicillin (46.8%); followed by nalidixic acid (19.0%), ciprofloxacin (12.1%), cefotaxime (8.6%) and chloramphenicol (5.2%). The prevalence of AMR E. coli was 67.2%, and 29.3% were MDR. Two (3.4%) isolates were identified to be ESBL producers, harboring the CTX-M gene. The study results also showed that broiler farmers were aware and knowledgeable of antibiotic resistance, although knowledge about its impact on human health was low. This study demonstrated the presence of resistant and ESBL producing E. coli among poultry farm workers.

Background The use of antimicrobials in layer poultry production for improved production, growth promotion, prophylaxis and treatment purposes has contributed to the development of antimicrobial resistance (AMR) in poultry. In Zambia, there is a paucity of information on the prevalence and AMR patterns of Enterococcus species isolated from laying hens. Objectives This study investigated the prevalence and AMR patterns of enterococci isolated in layer hens in Lusaka and Copperbelt provinces of Zambia. Methods A cross-sectional study was conducted from September 2020 to April 2021. Three hundred and sixty-five pooled cloacal swab samples were collected from 77 layer poultry farms. Enterococci identification and confirmation were performed using Analytical Profile Index (API 20 STREP) and 16S rRNA sequencing, respectively. A panel of nine antibiotics was used for antibiotic susceptibility testing and interpreted according to the CLSI 2020 guidelines. Data were analysed using SPSS version 23 and WHONET 2020. Results A total of 308 (83%) single Enterococcus species isolates were obtained and showed resistance to tetracycline (80.5%), erythromycin (53.6%), quinupristin/dalfopristin (53.2%), ampicillin (36.72%), vancomycin (32.8%), linezolid (30.2%), ciprofloxacin (11.0%), nitrofurantoin (6.5%) and chloramphenicol (3.9%). The prevalence of enterococci resistant to at least one antibiotic was 99.4% (n = 306), of which 86% (n = 265) were MDR. Conclusions This study found a high prevalence of antimicrobial-resistant enterococci. The presence of MDR requires urgent intervention and implementation of AMR surveillance strategies and antimicrobial stewardship programmes in layer poultry production in Zambia.

Antimicrobial resistance (AMR) of foodborne pathogens is of public health concern, especially in developing countries such as Zambia. This study was undertaken to determine the antimicrobial resistance profiles of Escherichia coli (E. coli) and Salmonella isolated from retail broiler chicken carcasses purchased from open markets and supermarkets in Zambia. A total of 189 E. coli and five Salmonella isolates were isolated. Identification and confirmation of the isolates were done using Analytical Profile Index (API 20E) (Biomerieux®) and 16S rRNA sequencing. Antimicrobial susceptibility tests (AST) were performed using the Kirby Bauer disk diffusion technique using a panel of 9 antibiotics. WHONET 2018 software was used to analyze AST results. The E. coli isolates were mostly resistant to tetracycline (79.4%), ampicillin (51.9%), and trimethoprim/sulfamethoxazole (49.7%). Two of the five Salmonella isolates were resistant to at least one antibiotic. This study has demonstrated the presence of AMR E. coli and Salmonella on retail broiler chicken carcasses from open markets and supermarkets, which is of public health concern.

Background Antimicrobial resistance (AMR) of foodborne pathogens is of public health concern, especially in developing countries such as Zambia. This study was undertaken to determine the antimicrobial resistance profiles of Escherichia coli (E. coli) and Salmonella isolated from raw retail broiler chicken carcasses purchased from open and supermarkets in Zambia.Results A total of 189 E. coli and five Salmonella isolates were isolated. Identification and confirmation of the isolates were done using Analytical Profile Index (API 20E) (Biomerieux®) and 16S rRNA sequencing. Antimicrobial susceptibility tests (AST) were performed using the Kirby Bauer disk diffusion technique using a panel of 10 antibiotics. Multiplex PCR was used to determine the presence of three target genes encoding for resistance: tetA, Sul1 and blaCTX-M. WHONET 2018 software was used to analyse AST results. The E. coli isolates were mostly resistant to tetracycline (79.4%), ampicillin (51.9%), and trimethoprim/sulfamethoxazole (49.7%). Two of the five Salmonella isolates were resistant to at least one antibiotic. Forty- seven (45.2%) of the 104 isolates that were screened for the presence of the resistant genes possessed at least one of the targeted resistance genes.Conclusion This study has demonstrated the presence of AMR E. coli and Salmonella on raw retail broiler chicken carcasses from open and supermarkets, which is of public health concern.