Bacteriophage Typing of Canine Staphylococci : III. Phage Typing by Use of Canine Phages with Special Reference to the Epizootiology of Staphylococcosis

Abstract

The canine phage set established in a previous study was used practically for the typing of staphylococcal strains isolated from dogs in the Taipei area. Of 268 strains, 90 (33.6%) and 27 (10.0%) were typable at 1, 000 and 1 RTD, respectively. The former were distributed to 8 phage groups, of which group I was the most predominant, consisting of 40 strains. This group was followed by groups II, V, VI, VII, III and IV, and a mixed group in the decreasing order listed. When 16 phages were used, a high frequency of lysis was obtained with 4 phages of group I and 3 phages of group II, but there was no remarkable difference in the number of typable strains between any two phage concentrations. This result indicated a good reproducibility of phage patterns. A distinct difference in host range was observed among the N.C.T.C., bovine and canine phages. The lytic activities of canine phages were almost restricted to strains producing white pigment. More typable strains seemed to be isolated from patients with otitis externa and pyoderma than from the normal auditory canal and skin. Group I strains were obtained predominantly from otitis externa, pyoderma, and normal skin, but not from the normal auditory canal. Staphylococcal strains of the same phage pattern or of the same phage group were frequently found in the auditory canals and skin of a dog. This result suggested transmission of a strain to different sites of the dog. Antibiotic resistance was demonstrated in 91 of 189 strains producing white pigment. Almost all the 91 strains were resistant to PC and/or SM. These resistant strains seemed to be more phage-typable than the sensitive ones. There was no particular correlation between the phage group and drug resistance.