Staphylococcus aureus complex from animals and humans in three remote African regions

Area of Science:

• Microbiology
• Zoonotic Diseases
• Public Health

Background:

• Staphylococcus schweitzeri, a divergent Staphylococcus aureus clade, primarily colonizes nonhuman primates and bats in sub-Saharan Africa.
• The potential for Staphylococcus schweitzeri transmission to humans remains largely unknown, necessitating investigation into interspecies bacterial exchange.

Purpose of the Study:

• To investigate the transmission dynamics of Staphylococcus aureus and Staphylococcus schweitzeri between humans, domestic animals, and wildlife in three African regions.
• To assess the prevalence of these bacteria and identify potential transmission routes and antimicrobial resistance patterns.

Main Methods:

• A cross-sectional study involving nasal and pharyngeal swabs from 1288 humans and 698 animals across Côte d'Ivoire, Gabon, and DR Congo.
• Bacterial isolates underwent spa typing, multilocus sequence typing, antimicrobial susceptibility testing, and virulence factor analysis.

Main Results:

• Staphylococcus schweitzeri was detected in monkeys at all sites, but no human transmission was observed despite frequent human-wildlife contact.
• Human-associated Staphylococcus aureus strains (ST1, ST6, ST15) were identified in domestic animals and nonhuman primates, suggesting human-to-animal transmission.
• Methicillin-resistant Staphylococcus aureus (MRSA) prevalence varied by region (0% in Gabon, 1.7% in DR Congo, 5.3% in Côte d'Ivoire), with the ST88 clone being predominant.

Conclusions:

• No evidence supports Staphylococcus schweitzeri transmission from animals to humans, though phylogenetic proximity warrants continued monitoring.
• Human-to-animal transmission of Staphylococcus aureus was observed, highlighting the complexity of bacterial exchange in diverse ecological settings.
• The ST88-MRSA clone is prevalent in Côte d'Ivoire, indicating a significant regional public health concern.