Capsular Polysaccharide Serotypes of Coagulase-Positive Staphylococci Associated with Tenosynovitis, Osteomyelitis, and Other Invasive Infections in Chickens and Turkeys: Evidence for New Capsular Types

To study the role of capsular polysaccharides in staphylococcal infections in chickens and turkeys, we surveyed 101 coagulase-positive isolates obtained from investigators in geographically diverse locales in the United States and Canada. Fifty-six isolates were obtained from chickens; 51 (91%) were type 5, and 5 (9%) were type 8. Forty isolates were obtained from turkeys; 13 (33%) were type 5, 15 (38%) were type 8, and 12 (29%) were untypable. Five type 5 isolates were obtained from poultry of uncertain species. Two untypable turkey isolates were studied further. Rabbit serum obtained after immunization with formalin-killed staphylococci was type-specific as assessed by a tube agglutination test and promoted opsonophagocytosis of the isolate that had been used for immunization. Chromatography of carboxy-reduced capsular polysaccharide from one of the isolates suggested that mannoseaminouronic acid was present in the unreduced polysaccharide. The spectrum obtained by 13C-nuclear magnetic resonance suggested the presence of N-acetyl sugars such as mannoseaminouronic acid and 6-deoxy sugars such as N-acetyl fucosamine. The structure of the polysaccharide differed from that of the type 5 and type 8 capsular polysaccharides. Thus, poultry isolates can be classified into at least four serotypes on the basis of their capsular polysaccharides. This observation provides a new focus for investigation into the epidemiology and virulence determinants of this important pathogen in chickens and turkeys.