Prevalence of virulence factors in Staphylococcus intermedius isolates from dogs and pigeons
1 Department of Animal Health 2, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Sagamihara, Kanagawa, 229-8501, Japan
2 Department of Molecular Microbiology/Immunology, Faculty of Allied Health Sciences, Thammasat University, Rangsit Campus, Pathum-thani, 12121, Thailand
3 Center for Medical Sciences, School of Health Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Inashiki, Ibaraki, 300-0394, Japan
BMC Veterinary Research 2006, 2:4 doi:10.1186/1746-6148-2-4Published: 26 January 2006
Staphylococcus intermedius has been isolated from healthy dogs and pigeons as well as diseased dogs. Similar to Staphylococcus aureus, S. intermedius is known to carry many virulence factors but most of these factors remain to be studied. In this study, we examined 106 S. intermedius isolates (44 dog isolates and 62 pigeon isolates) for their hemolytic activity, biofilm formation, protease activity, and clumping factor and protein A production.
Forty-three dog isolates (97.7%) and all pigeon isolates were hemolytic on sheep RBCs with a mean hemolytic titer of 336.7 and 47.32, respectively, whereas 43 dog isolates (97.7%) and 11 pigeon isolates (17.7%) exhibited a significant difference in their hemolytic activity on rabbit RBCs with a mean hemolytic titer of 11.04 and 3.76, respectively (p < 0.0005). The mean biofilm formation activity for dog isolates was 0.49, which was significantly higher than that (0.33) for pigeon isolates (p < 0.0005). Twenty-four dog isolates (54.5%) and 11 pigeon isolates (17.7%) were protease positive. Twenty-four dog isolates (54.5%) were clumping factor- and protein A- positive.
S. intermedius strains carrying the virulence factors examined in this study were more prevalent in dogs than pigeons.