Characterisation of Staphylococci Isolated from Poultry

The characteristics of staphylococci isolated from arthritis-synovitis lesions in broiler breeding stock, and strains isolated from poultry without known history of staphylococcal disease, were investigated. All lesion-strains were coagulase positive, produced α haemolysin, lysozyme, phosphatase, acetoin from glucose, fermented mannitol in anaerobic conditions, split galactose, maltose, lactose and mannose. The majority of them produced DNase, gelatinase and urease, cleared egg yolk- and milkagar, and hydrolysed Tween 80. None was fibrinolysin positive. Coagulase positive non-lesion strains showed similar characteristics. The S. epidermidis strains investigated, could not be inserted with certainly in one of Baird-Parker’s subgroups. Sixty-two percent of the S. aureus strains were typable with the international set of basic typing phages, most of them only at the RTD × 1000 dilution. It was suggested that strains derived from poultry may be different from strains isolated from other animals or humans. Minimum inhibitory concentrations (M.I.C.) were determined for the S. aureus strains. Eighty percent of the strains produced penicillinase. Fifty percent of the strains were resistant to tetracycline and ten percent to streptomycin. Six strains (8%) showed complete cross-resistance when tested for susceptibility to the marcolide antibiotics and lincomycin. The same strains also showed a slightly decreasd susceptibility for the peptolide antibiotic virginiamycin.