Characteristics of Staphylococcus aureus isolated from healthy and diseased chickens

In this study, Staphylococcus aureus was isolated from healthy chickens, and the characteristics of the strains isolated from healthy and diseased chickens were examined. The results obtained were as follows. 1) S aureus was isolated from 103 (79.2%) of 130 healthy chickens. The isolation rate from the nares was 49.2%, and the skin 75.4%. 2) All of the 219 strains from healthy (n=170) and diseased (n=49) chickens produced heat-labile and heat-stable DNase. The majority of them produced alpha-hemolysin, protease, gelatinase, hyaluronidase, acetoin from glucose, hydrolyzed egg yolk and Tween 80, and grew on crystal violet agar in colonies of the positive type A. Fibrinolysin was produced by 18.8% of the healthy strains, and 4.1% of the diseased strains. Protein A production was detected in only 8 diseased strains. All of the 219 strains produced acid from fructose, galactose, glucose, lactose, maltose, mannitol, mannose, sucrose and trehalose, but not from arabinose, dextrin, raffinose, salicin, sorbitol and xylose. There was no remarkable difference in characteristics between strains of healthy chickens and those from diseased chickens. 3) 169 (99.4%) of the 170 healthy strains and 41 (83.7%) of the 49 diseased strains were biotyped. The majority of them were poultry ecovar. 113 (66.5%) of the 170 healthy strains and 24 (49.0%) of the 49 diseased strains were typable with the poultry phages. The majority of the healthy strains belonged to group III. Diseased strains were divided into groups I, II and III at equal percentages. 4) 148 (96.1%) of 154 healthy strains and 45 (95.7%) of 47 diseased strains were typable with eight coagulase typing antisera. The majority of them belonged to type II. 5) None of the 219 stains produced either enterotoxins or toxic shock syndrome toxin-1. 6) Four (4.3%) of 92 healthy strains and 12 (24.5%) 49 diseased strains were resistant to one or more of 5 antibiotics