First Report of Antimicrobial Susceptibility and Virulence Gene Characterization Associated with Carriage in Healthy Camels from Tunisia.

A total of 318 nasal and rectal swabs were collected from 159 apparently healthy camels () randomly selected from five regions in southern and central Tunisia and screened for carriage. spp. were recovered from 152 of 159 camels studied (95.6%) and in total 258 swabs (81%) were positive. Among these isolates, 16 were coagulase positive (CoPS) (6.2%) and were characterized by biochemical and molecular tests as . These were isolated from 14 camels (8.8%) with co-carriage in nasal and rectal mucosa by two camels. All isolates recovered were methicillin-susceptible Staphylococcus aureus (MSSA) and were characterized by typing and PFGE. Three different types were recovered: t729, t4013 and a type newly registered as t19687, which was the most common. PFGE analysis revealed seven different patterns and these were characterized by MLST, which revealed five different sequence types (ST6, ST88, ST3583 and two new sequences, ST6504 and ST6506). All isolates harbored different virulence genes, including , encoding delta hemolysin; E-D, encoding bicomponent leukotoxin LukE-LukD; the B gene, encoding clumping factor B; the gene, encoding laminin-binding protein; and 8, encoding capsule type 8. Fifteen isolates harbored hemolysin beta () and fourteen encoded hemolysin alpha () and hemolysin G2 (). Adhesin factors, including and , were detected in five and four isolates respectively. Binding proteins, including collagen () and elastin-binding protein (), were detected in two isolates while fibrinogen-binding protein () was identified in four isolates. This study provides the first set of genotyping data on the population structure and presence of toxin genes of strains in Tunisian camels.