Comparative ribotyping of Staphylococcus intermedius from dogs, pigeons, horses and mink.

Strains of Staphylococcus (S.) intermedius from dogs, pigeons, horses and mink were typed by comparison of rRNA gene restriction fragment length polymorphisms (ribotyping) and the resulting ribotypes examined by cluster-analysis. Digestion of whole-cell DNA with HindIII resulted in 9 ribotypes with 3 to 4 bands. Separation of isolates from different host animal species was not possible. EcoRI yielded 11 different patterns with 4 to 9 fragments. The EcoRI-ribotypes of all canine strains grouped in one cluster encompassing four closely related ribotypes. Isolates were indistinguishable with respect to their origin from cases of canine pyoderma or from healthy carriers. In contrast, pigeon and equine strains expressed variety of ribotypes including some strains with patterns similar to canine isolates. However, for canine versus pigeon and equine strains the difference in distribution among ribotypes was significant (P < 0.001). The data might suggest that pigeons and horses carry S. intermedius transiently and might be able to spread these bacteria to other animal species.

Insertion elements in Staphylococcus intermedius.

Staphylococcus intermedius cultures from dogs, pigeons, horses and mink were investigated for the prevalence of the insertion elements IS256 and IS257 in relation to their antibiotic resistance. Copies of IS256 could not be detected in any of the Staph. intermedius isolates tested whereas single copies of IS257 occurred in the isolates from dogs and horses. The mink strains did not harbour IS257 elements, whereas Staph. intermedius isolates from pigeons carried multiple copies of IS257 as predicted from the hybridization patterns obtained with a gene probe derived from the internal part of the IS257-encoded transposase gene. Independently of the origin of the Staph. intermedius isolates, all IS257 copies were found to be located in the chromosomal DNA. The large number of chromosomal IS257 copies in the pigeon strains might help to explain chromosomal multiresistance in many of those strains.

Characterization of Staphylococcus intermedius from healthy dogs and cases of superficial pyoderma by DNA restriction endonuclease patterns.

In order to study the possible clonal relation of Staphyloccocus (S.) intermedius from canine superficial pyoderma and from healthy carriers, isolates from pustular swabs and from vaginal, nasal and normal skin sabs were typed using macrorestriction analysis with Sma I and pulsed-field gel electrophoresis. From the size of the resulting fragments the size of the chromosome of S. intermedius could be determined to be roughly 1500 +/- 200 kb on the average. The fingerprints were very heterogeneous though characteristically distinct from patterns of (human) S. aureus as published by others. Strains from superficial pyoderma were not found to be more similar to each other than strains from healthy carriers. Therefore it was concluded that strains from this type of skin infection probably did not belong to a certain subpopulation of S. intermedius, which might have indicated a higher virulence of these strains.