Asymptomatic Carriage and Antimicrobial Resistance of Salmonella in Humans and Poultry in Rural Burkina Faso: Phenotypic and Genotypic Profiles and Associated Risk Factors

TL;DR

This study examines Salmonella carriage and antibiotic resistance in humans and poultry in rural Burkina Faso, finding high resistance rates and risk factors like age and season.

Contribution

The study provides new insights into Salmonella's phenotypic and genotypic resistance profiles and risk factors in a rural African setting.

Findings

Salmonella carriage was detected in 8.7% of humans and 7.2% of poultry.

Poultry isolates showed higher resistance to cephalosporins compared to human isolates.

Resistance genes like fosA7 and virulence genes like T3SS-1 and T3SS-2 were found in both hosts.

Abstract

Food-borne diseases affect nearly 10% of the global population annually, with Salmonella being a major cause, particularly impacting children, the elderly, and populations in low- and middle-income countries. This study aimed to assess the prevalence, serotype distribution, antibiotic resistance profiles, and genetic determinants of resistance and virulence of Salmonella enterica in humans and poultry in the Nanoro health district. A community-based cross-sectional study involving humans and poultry was conducted in the Nanoro health district. Fresh stool samples (human and poultry cloacal/cecal) were collected, transported under sterile conditions, and processed within two hours using standard bacteriological methods. Phenotypic antibiotic resistance was determined by the Kirby–Bauer disk diffusion method, and whole-genome sequencing (Illumina) identified serotypes, resistance genes, and virulence factors. Logistic regression analyzed associations between Salmonella carriage and host or environmental factors. Salmonella enterica carriage was detected in 8.7% of humans and 7.2% of poultry. Human isolates showed 24% resistance to cephalosporins, while poultry isolates showed 36.8% resistance. Resistance genes, including fosA7, qnrB19, and a cryptic aminoglycoside resistance gene, and virulence genes encoding T3SS-1 and T3SS-2, were detected in both hosts. Logistic regression indicated that residence in Sitaon and Zimidin was associated with ~70% lower odds of carriage (aOR = 0.3), while individuals aged 11–20 and 51–60 years had 2.8-fold higher odds. Carriage was also 60% higher during the rainy season. These findings suggest possible cross-transmission of Salmonella between humans and poultry and the circulation of resistant, potentially virulent strains in the community. Seasonal and age-related variations highlight environmental and behavioral influences on asymptomatic carriage. Integrated One Health surveillance and targeted hygiene interventions are essential to reduce Salmonella transmission and antimicrobial resistance in rural settings.