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J Capstick

Publications and source records attributed to J Capstick.

5 recordsLinked to original sources

Molecular typing of Staphylococcus aureus of bovine origin by polymorphisms of the coagulase gene.

Mastitis caused by Staphylococcus aureus is a disease of major economic importance to the dairy industry. Transmission occurs during milking, with chronically-infected cows acting as the major reservoirs of infection. PCR-coagulase gene typing of 151 S. aureus isolates from seven farms generated only six PCR types, with 110 (73%) isolates assigned to PCR type 1 and 23 (15.2%) isolates assigned to type 2. PCR type 1 was the predominant type on five of the seven farms, including farms in geographically separated regions of Victoria, while type 2 predominated on two farms. With the exception of the 41 isolates from one farm, all isolates were resistant to penicillin, but susceptible to other antibiotics that are routinely used to manage mastitis in dairy cattle. Nine of 11 cows with chronic S. aureus infection showed evidence of persistence of a single PCR type for periods of up to 9 months. Two different PCR types of S. aureus were isolated from the other two cows over the same period.

Animals↗

A study of phenotypic variation of Staphylococcus epidermidis using Congo red agar.

This study examines a series of phenotypic variants of Staphylococcus epidermidis that were generated from a pair of parent variants, isolated from valvular tissue of a patient with prosthetic valve endocarditis. The variants were initially classified by examining their colonial morphology on Congo red agar. In addition to differences in Congo red binding and colonial morphology, they differed in the expression of several surface components and enzymes. Despite these phenotypic differences, all variants had the same restriction endonuclease profile of plasmid DNA. Examination of a collection of clinical isolates demonstrated that phenotypic variation is a common property of S. epidermidis. The ability to express different combinations of surface components and enzymes could contribute to the virulence of S. epidermidis strains by enabling these organisms to colonize a range of diverse environments.

Agar↗

Phenotypic variation of Staphylococcus epidermidis isolated from a patient with native valve endocarditis.

Two colonial variants of Staphylococcus epidermidis were isolated from the valvular tissue of a patient with native valve endocarditis. In addition to differing in colonial morphology, the two variants differed in hemolysis on blood-containing media, in adherence capacity, and in the expression of certain enzymes. Under suitable conditions, both variants were themselves capable of phenotypic variation, although they differed in the rate at which variants were generated. The variants yielded identical profiles on restriction endonuclease analysis of plasmid DNA and pulsed-field gel electrophoresis of whole-cell DNA. This report suggests a possible role for phenotypic variation in coagulase-negative staphylococcal virulence. Congo red agar would be an excellent medium for studying the contribution of variation to the virulence of these organisms.

Adult↗