Bovine mammary glands were inoculated intracisternally with a streptomycin-resistant (SR) strain of Corynebacterium bovis to determine the number of colony-forming units (CFU) required to induce colonization and to maintain persistence of C bovis colonization throughout lactation and involution. Streptomycin resistance was used as a strain marker. Uninfected quarters in cows during midlactation were challenge exposed with successively higher numbers of SR C bovis until all quarters became colonized. Inoculum containing 790 CFU of SR C bovis established colonization in only 7 of 38 quarters. Colonization persisted in only 4 of these quarters by 23 days after inoculation. Eleven quarters were reinoculated with higher numbers of SR C bovis, and all became colonized by the time challenge-exposure inoculum contained 8 X 10(4) CFU. Colonization persisted throughout the 93-day experimental period. Somatic cell counts were significantly (P less than 0.01) higher in SR C bovis-colonized quarters after inoculation than before. Sixteen additional quarters were inoculated with a mean number of 8 X 10(4) CFU of SR C bovis 7 days before suppression of lactation. All quarters became colonized, and SR C bovis was shed during the experimental period; throughout the nonlactating and peripartum periods, high numbers of SR C bovis in pure culture were shed from 13 of 16 quarters.

Out of 63 bacteriologically examined sanguineous fluids samples which were collected from Oedematous Skin Disease (O.S.D.) lesions, 37 isolates of C. pseudotuberculosis (C.p.) were recovered. The sensitivity tests revealed that isolates were highly sensitive to trimethoprim + sulphamethoxazole, amoxycillin, gentamicin and enrofloxacin. Diphtheria toxin (DT) produced by C. pseudotuberculosis of buffalo was determined by using the double immunodiffusion technique, it was applied on concentrated exotoxins which was prepared from C.p. isolates against Diphtheria toxin antiserum, its results were 15 (40.54%) positive and 22 (59.46) %) negative to presence of DT. Virulence of isolates having only phospholipase D ( PLD) or both PLD and DT was assayed by S/C inoculation of exotoxines prepared from isolates in guinea pigs, 15(40.54%) guinea pigs died within 18 hours while 22 (59.46%) guinea pigs died during 48 hours. An important point in this investigation that there have been very rare previous reports describing the production of DT by local isolates of C. pseudotuberculosis of buffalo.

Clinical examination of 380 rearing sheep revealed that 30 animal were suffering from skin abscesses with an incidence of (7.89%). Bacteriological examination of 30 swabs from affected sheep revealed isolation of 30 isolates of C. pseudotuberculosis (48.39%) , 18 isolates of S. aureus (29.03%) and 14 isolates of S. aureus subsp. anaerobius (22.58).The isolated bacteria were identified morphologically and biochemically.The results of animal pathogenicity test showed that C. pseudotuberculosis isolates were 100% pathogenic to guinea pigs and 80% of S.aureus isolates were pathogenic to mice, while all isolates of S. aureus subsp. anaerobius were pathogenic to mice. The dead animals showed haemorrhage and symptoms of septicaemia, C. pseudotuberculosis, S.aureus and S. aureus subsp. anaerobius were reisolated from the dead animals. Antimicrobial sensitivity of C. pseudotuberculosis , S. aureus and S. aureus subsp. anaerobius isolates to some antimicrobial agents which usually used in farms showed that from 90% to 100% of C. pseudotuberculosis isolates were sensitive to erythromycin, amoxicillin, tetracycline ,streptomycin, ampicillin and rifampicin while S. aureus isolates (from 55% to 66%) were sensitive to rifampicin,tetracycline ,erythromycin and streptomycin, while S. aureus subsp. anaerobius isolates were moderately resistant to all used antimicrobial agents.

Caseous lymphadenitis (CLA) is a chronic and contagious disease of sheep and goats caused by Corynebacterium (C.) pseudotuberculosis. A four-year-old female Saanen dairy goat was submitted to the Animal Disease Diagnostic Center at National Veterinary Research and Quarantine Service. The clinical signs of the goat were emaciation, abortion and quadriplegia. The multifocal nodules of lymph nodes were encapsulated and filled with whitish caseous contents on the cut surface. Histopathologically, lymph nodes displayed suppurative and necrotizing granulomas. Caseous necrosis was diffusely observed in the center of the lymph nodes. Gram positive bacilli were shown in the lesions. C. pseudotuberculosis was isolated and confirmed by the biochemical tests and PCR assay. Based on clinical signs, histopathological examination and bacterial isolation, we diagnosed this case as CLA. To our knowledge, this is the first report of CLA in a Saanen dairy goat in Korea.

Colostrum-deprived lambs and CF1 mice were vaccinated with water-in-oil emulsion vaccines containing nonviable whole cells (WC) of Corynebacterium pseudotuberculosis with and without muramyl dipeptide (MDP). Efficacy of vaccines was determined from the survival of mice and lesions in lambs after IV injection of 10(4) colony-forming units of C pseudotuberculosis. In mice, protection was related to the concentration of WC in the vaccine. At 50, 100, or 150 micrograms of WC, protection was good (78.8%). At 10 or 25 micrograms of WC, protection was considerably less (54.7%). At high WC concentrations, protection could only be moderately increased to 82.3% with high (50 and 100 micrograms) concentrations of MDP or increased to 90% protection with low (5 and 10 micrograms) concentrations of MDP. At low WC concentrations, protection significantly decreased to 32% (P < 0.025) with high concentrations of MDP, but significantly increased to 72.5% (P < 0.025) with low concentrations of MDP. Therefore, the amount of protection with lower concentrations of WC and MDP was comparable with the amount of protection with higher concentrations of WC without MDP. In lambs, high prechallenge antibody titers (geometric mean titers from 5.1 to 5.4 by day 35) were observed after vaccination with WC. Protection and vaccination site abscesses in lambs were related to the concentration of WC and MDP. Pulmonary or vaccination site abscesses were not observed in 4 of 4 lambs vaccinated with 1 mg of WC + 50 micrograms of MDP.