Biotyping of Coagulase-Positive Staphylococcus aureus and Staphylococcus intermedius Strains Isolated from Various Animals in Japan

Abstract

A total of 1708 strains of coagulase-positive staphylococcal species, Staphylococcus aureus (n=1541) and S. intermedius (n=167) isolated from humans and 17 kinds of animals in Japan were subjected to the biotyping scheme of Hajek and Marsalek. Of the 1708 strains tested, 1470 (86.1%) could be classified into biotypes and 238 (13.9%) could not be assigned to any of the known 6 biotypes. All S. aureus strains obtained from quails and pigeons, and the majority of human S. aureus strains were classified as biotype A. Chicken and swine S. aureus strains were predominately classified as biotype B. Bovine S. aureus strains were divided into biotypes B and C at an equal percentage. As for canine, equine and pigeon strains, the strains of S. aureus isolated from dogs and horses were classified as biotypes A, B or C. All S. intermedius strains from dogs, horses and pigeons were classified as biotype E. About 56% of S. aureus strains isolated from laboratory (rabbits, mice, rats, guinea pigs and a nude mouse) and wild (Rattus norvegicus, Rattus rattus, mice and a ferret) rodents were classified as biotypes A, B, C or D. Of the 238 unclassified strains, 202 were an extremely homogeneous group of S. aureus. They produced fibrinolysin, yellow pigment and DNase, hydrolyzed egg-yolk and Tween 80, coagulated both human and bovine plasmas. Thus these 202 strains showed properties intermediate between human biotype A and bovine biotype C, producing fibrinolysin like human biotype A and coagulating bovine plasma like bovine biotype C. Therefore, we propose that the group of these organisms should be added to the new biotype designated as biotype G in the biotype classification of Hajek and Marsalek.