Assessment and genomic analysis of Salmonella and Campylobacter from different stages of an integrated no-antibiotics-ever (NAE) broiler complex: a longitudinal study

The objective of this study was to determine prevalence and perform genomic analysis of Salmonella spp. and Campylobacter spp. isolated from different stages of an integrated NAE broiler complex. Environmental samples were screened with 3M-Molecular Detection System (MDS) and MDS positive samples were further processed for confirmation of results and identification. Core genome-based phylogenies were built for both bacteria isolated from this study along with selected NCBI genomes. The odds ratios and 95% confidence limits were compared among stages and sample types (α < 0.05) using multivariable model. Based on MDS results, 4% and 18% of total samples were positive for Salmonella spp. and Campylobacter spp. respectively. The odds of Salmonella detection in hatchery samples were 2.58 times as likely as compared to its detection in production farms' samples (P = 0.151) while the odds of Campylobacter detection in production farms' samples were 32.19 times as likely as its detection in hatchery (P = 0.0015). Similarly, the odds of Campylobacter detection in boot swabs, soil, water, and miscellaneous samples were statistically significant (P < 0.05) as compared with fly paper as reference group. The serovars identified for Salmonella were Typhimurium, Barranquilla, Liverpool, Kentucky, Enteritidis, Luciana, and Rough_O:r:1,5. For Campylobacter, the species identified were Campylobacter jejuni and Campylobacter coli. Phylogeny results show close genetic relatedness among bacterial strains isolated from different locations within the same stage and between different stages. The results show possibility of multiple entry points of such bacteria entering broiler complex and can potentially contaminate the final raw product in the processing plant. It suggests the need for a comprehensive control strategy with strict biosecurity measures and best management practices to minimize or eliminate such pathogens from the poultry food chain.

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

Residues of antimicrobials used in farm can exert selective pressure and accelerate the occurrence of multidrug resistant bacteria in litter. This study aimed to investigate the resistance profile of Escherichia coli isolated from poultry litter. A total of 101 E. coli strains was isolated from 229 litter samples collected and stored for two months in the laboratory at room temperature. Antimicrobial susceptibility testing was performed using the disk diffusion method. An overall resistance prevalence of 58.4% (95% CI: 48.8-68.0) was obtained with 59 E. coli strains resistant to various antimicrobial agents. High levels of resistance were observed with ciprofloxacin (21/59: 36%), imipenem (27/59: 45%), norfloxacin (44/59: 74%), ceftriaxone (44/59: 74%), and levofloxacin (44/59: 75%). These antimicrobials classified under the Watch group by WHO are indicators of the high AMR risk to public health in Cameroon. Multivariable logistic regression analysis revealed that a greater probability of high level of E. coli multidrug resistance was associated with lack of training in poultry farming (OR = 0.13, p = 0.01), less experience in poultry farming (OR = 11.66 p = 0.04), and the high frequency of digestive tract disease (OR = 0.10; p = 0.001). This study revealed that poultry litter constitutes a potential source of dissemination of resistant germs from farm animals to the environment and humans.