A Review of Avian Pathogenic Escherichia coli (APEC) in Guinea Fowls (Numida meleagris) of Southern Africa: Antimicrobial Resistance and Virulence Genomics and Control Strategies.

Abstract

Avian Pathogenic Escherichia coli (APEC), the primary causative agent of colibacillosis, is a major and growing threat to global poultry production, leading to significant economic losses. In Southern Africa, the guinea fowl (Numida meleagris) is an economically, culturally, and nutritionally important indigenous poultry species for local communities. However, its production is constrained by infectious diseases such as colibacillosis posing a significant yet understudied challenge. This review synthesises the current, albeit limited, knowledge on APEC in Southern African guinea fowls. We detail the key virulence genes including adhesins (fimH), iron acquisition systems (iutA, fyuA), and immune evasion factors (iss) that facilitate pathogenesis. A critical concern is the convergence of these virulence genes with multidrug resistance (MDR) on mobile genetic elements. This fusion drives the emergence of dangerous, high-risk bacterial clones. Genomic studies confirm that APEC shares significant genetic overlap with human extra-intestinal pathogenic E. coli (ExPEC), such as sequence types ST95 and ST131, underscoring a substantial zoonotic threat. While conventional PCR has been instrumental in initial virulence profiling, we advocate for the widespread application of Whole-Genome Sequencing (WGS) to elucidate the unique population structure of guinea fowl APEC, precisely assess zoonotic risk, and guide interventions. Effective control requires an integrated, One Health approach encompassing stringent antibiotic stewardship, enhanced genomic surveillance, and the development of targeted strategies such as vaccines, phage therapy, and robust biosecurity measures tailored to guinea fowl farming systems. Filling these knowledge gaps is essential for safeguarding guinea fowl health, ensuring food security, and mitigating the public health crisis of antimicrobial resistance.