Antibiotic-resistant Salmonella species and Escherichia coli in broiler chickens from farms, abattoirs, and open markets in selected districts of Zambia

Abstract

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.

Poultry Litter Contamination by Escherichia coli Resistant to Critically Important Antimicrobials for Human and Animal Use and Risk for Public Health in Cameroon

“…The resistance rate observed with ciprofloxacin (36%) was similar to 42% reported by Adelowo et al [ 28 ] in Nigeria, lower than 57% reported by Louokdom et al [ 29 ] in Cameroon, but higher than 13% reported by Vounba et al [ 17 ] in Senegal and 22% by Nfongeh et al [ 30 ] in Nigeria. As for imipenem, the resistance rate observed in this study was higher than 4% reported by Phiri et al [ 27 ] in Zambia. The emergence of carbapenem resistance is alarming as the World Health Organization classifies these molecules as critically important antimicrobials and carbapenems are the last-resort antimicrobials for treating a wide range of infections caused by multidrug-resistant Gram-negative bacteria [ 27 ].…”

“…As for imipenem, the resistance rate observed in this study was higher than 4% reported by Phiri et al [ 27 ] in Zambia. The emergence of carbapenem resistance is alarming as the World Health Organization classifies these molecules as critically important antimicrobials and carbapenems are the last-resort antimicrobials for treating a wide range of infections caused by multidrug-resistant Gram-negative bacteria [ 27 ]. Resistance rate of E. coli to ceftriaxone (74%) in this study was higher than 18.9% reported by Abdalla et al [ 31 ] in South Africa and 59% reported by Ngogang et al [ 26 ] in Cameroon while, 75% of resistance observed with levofloxacin was higher than 45.63% reported by Tchapa and Chapagain [ 32 ] in Nepal.…”

“…The present study was initiated with the assumption that the storage of litter in plastic bags at room temperature for at least two months may help to reduce potential pathogens and this period approximately correspond to the delay period observed by most farmers before application of litter as, manure. It appears that isolation frequency of 45.41% was lower than 59.1% reported in the fresh broiler litter in previous studies in Cameroon [ 26 ] and 58.0% in Zambia [ 27 ]. E. coli is a commensal bacteria present in the intestinal tract of chicken and poultry environment, and hence storage of samples may have induced the destruction of some fragile strains.…”

Zoonotic Significance and Antimicrobial Resistance in Salmonella in Poultry in Bangladesh for the Period of 2011–2021

“…A significant level of colistin resistance was observed as ranging from 50% to 92.68% in Salmonella in broilers and layers in Bangladesh [27,28,30,41,44]. Similarly, Phiri et al [109] also reported 78.70% colistin resistance in Salmonella in Zambia. The main reservoirs for colistin resistance and transmission have been identified as livestock and poultry [110].…”

Antimicrobial resistance of Escherichiacoli and Salmonella isolated from retail broiler chicken carcasses in Zambia

“…[19] The disparity of findings could be attributed to a difference in processing methods and commercial production techniques that are highly automated in Thailand compared to the Zambian settings where the manual system is often used, hence exposing the carcasses to contamination. [29] The overall contamination level of Salmonella sp in all samples was low (1.5%). This was also observed in some studies done at the retail level.…”