Abstract:

Background: The burden of multidrug bacteria is resistant bacteria is increasing drastically and poses a major threat to human and veterinary medicine globally as it is associated with increased morbidity and mortality. Currently there is limited information on the resistance profiles and epidemiological cut-off values (ECVs) of E. coli isolated from poultry and pigs in Mwanza Tanzania. This study investigated the prevalence of multidrug resistance and ECVs of E. coli isolated from poultry and pigs.

Methodology: This was a cross sectional study involving 297 pigs, 191 broilers and 203 layers reared in Mwanza Tanzania between June and August 2021. Rectal/cloacal swabs were processed to isolate E. coli followed by disk antimicrobial susceptibility testing as per Clinical and Laboratory Standards Institute (CLSI) guidelines 29th edition Epidemiological cut-off value (EVCs) were determined using a computer software normalized resistance interpretation (NRI) and descriptive analysis was performed using STATA version 13.

Results: A total of 95.1% (657/691) E. coli isolates were isolated: pigs (n=2830), broilers (n=190) and layers (n=184). Overall, the multi-drug resistant (MDR) E. coli were observed in 63.2% (415/657) of isolates (Pigs 31.8%, Broilers 86.3%, and Layers 87.5%, P<0.001) While extended Spectrum Beta Lactamase (ESBL) production was observed in 17.8% (117/657) of isolates. The proportion of ESBL producing E. coli was significantly high in isolates from layers compared to pigs and broiler isolates (Layers 30.9%, Broilers 5.3% and Pigs 17.7%, p<0.001). Based on ECVs of antibiotics tested, E. coli from broilers, layers and pigs exhibited different population with the majority of E. coli from broilers and layers being non-wild-type to commonly used antibiotics. Exotic breeding, and recent antimicrobial use (P<0.001) was found to predict MDR colonization among poultry and pigs.

Conclusion: E. coli from layers and broilers are more resistant to commonly used antibiotics than E. coli isolates from pigs. Distinct populations of E. coli were circulating in layers, broilers and pigs based on ECVs of different antibiotics tested and this was likely due differences in antibiotic exposure and breeding type. Further research to establish the genotypes of E. coli circulating in these species are warranted to provide data to monitor the emergence of new E. coli strains/genotypes.