Characterization of United Kingdom isolates of Corynebacterium pseudotuberculosis using pulsed-field gel electrophoresis.

Caseous lymphadenitis is a chronic suppurative disease caused by Corynebacterium pseudotuberculosis and is responsible for serious economic losses to the sheep and goat industry. Caseous lymphadenitis was first reported for goats in the United Kingdom in 1990 and for sheep in 1991. Recent evidence suggests that the prevalence of the disease within the national flock is increasing. Fifty isolates of C. pseudotuberculosis from the United Kingdom comprising sheep and horse isolates, the original goat outbreak strain, and the type strain were characterized by biotyping, antimicrobial susceptibility, production of phospholipase D, and genotyping by pulsed-field gel electrophoresis using SfiI and SmaI. All of the isolates were confirmed as C. pseudotuberculosis, and all produced phospholipase D but none reduced nitrate. Restriction with SfiI generated 16 to 18 bands between 48.5 and 290 kb and differentiated six pulsotypes. We conclude that 80% of the strains tested were epidemiologically related to the outbreak strain and that the equine profile was distinct both phenotypically and genotypically.

Moredun Bordetella Medium, an improved selective medium for isolation of Bordetella parapertussis.

Bordetella parapertussis, previously thought to be an obligate human respiratory tract pathogen, has been isolated from sheep. Attempts to assess the prevalence of B. parapertussis in conventionally reared sheep by nasal swabbing proved futile with existing selective media because of extensive overgrowth with Mucor spp. and other nasal commensals. Moredun Bordetella Medium (MBM), which contains cycloheximide and spectinomycin at final concentrations of 0.5 mg/ml and 100 mu g/ml, respectively, was developed as an improved selective medium to isolate B. parapertussis from the nasal cavities of conventionally reared sheep. The selective ability of MBM was evaluated with 200 nasal swabs from conventionally reared sheep, and B. parapertussis was recovered from 31.5% of the samples. MBM facilitated the simple and effective isolation of B. parapertussis from ovine nasal swabs and, in successfully excluding overgrowth with other contaminants, proved superior to other test formulations evaluated and to existing conventional media.