• 대한수의학회지
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• 제48권2호
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• pp.139-143
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• 2008

We report here two cases of Rhodococcus (R.) equi-causing pneumonia of Throughbred foals in Gyeonggi-do in 2006. R. equi was isolated from the lung lesions of the dead foals, and from the feces and soils on the farms where the clinical cases of R. equi infection occurred. The isolates were characterized by biochemical properties, polymerase chain reaction for vapA gene and antimicrobial susceptibility. In drug susceptibility test, erythromycin, gentamycin, vancomycin, and rifampin were found to be the most susceptible for all isolates. These results suggest that R. equi pneumonia may be endemic in the horse-breeding farms in inland Korea and the farm environment may be widely contaminated with virulent R. equi.

• 대한수의학회지
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• 제59권3호
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• pp.141-149
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• 2019

From 1996 to 2014, 14 foals from nine farms in Jeju were diagnosed with a Rhodococcus equi infection. Clinically, most foals showed characteristic respiratory signs, including hyperthermia and dyspnea. The seasonal occurrence of R. equi infection in foals was higher in summer, such as June (eight foals; 57.1%) and July (four foals; 28.6%), than in the other seasons. The major cases of R. equi infections were observed among two-month-old (eight foals; 57.1%) and three-month-old (three foals; 21.4%) foals. Histopathologically, bronchopneumonia, abscess, and granulomatous pneumonia were the most prevalent lesions in the lungs of foals. Colonic ulcers and submucosal abscesses were found in a foal. Some foals showed granulomatous lymphadenitis and abscesses in the mesenteric and other lymph nodes. According to the polymerase chain reaction using 10 tissue samples of foals and nine R. equi isolates, the vapA gene was detected in 11/11 (100%) foals. Immunohistochemical staining using the anti-VapA monoclonal antibody was applied to detect the R. equi VapA antigen in the organs of foals. R. equi VapA antigens were demonstrated in most lungs and some mesenteric and hilar lymph nodes of 13 foals. Isolated virulent R. equi VapA bacteria showed high sensitivity to gentamicin, quinolones, rifampin, and vancomycin.

• 한국임상수의학회지
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• 제23권2호
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• pp.169-174
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• 2006

This work described 3 infection cases caused by Rhodococcus equi in foals between 3 and 5 months of age. The disease histories were not fully taken from local veterinarians. At least 1 sick foal has been treated with cephalothins followed by penicillins during approximately 1 week, but died without effectiveness and other foals rearing with the animal have been suffering from severe pneumonia which show high fever, laboring respiration, cough and/or nasal discharge. There were many abscessations into lungs of 2 foals in postmortem examination and another 1 sample was pus collected from abscess around the shoulder, indicating the osteomyelitis. Those bacteria were grampositive coryneform and were identified as a R. equi by a polymerase chain reaction (PCR) using primers for R. equi-specific vapA gene. The pathogens were usually resistant to penicillin, ampicillin, amoxycillin/clavulanic acid, cefazolin, clindamycin, sulfamethoxazol/trimethoprim, kanamycin, and tetracycline, while were sensitive to ciprofloxacin, norfloxacin, orfloxacin, gentamicin, erythromycin, neomycin, and vancomycin. Some more foals with respiratory symptoms in 1 horse farm were treated by orally administration with erythromycin during 2 weeks. Because the combination of erythromycin and rifampin has recommended as the treatment for R. equi infections in foals, the local equine veterinarian can choose those antibiotics for the treatment of this disease in future. However, another antimicrobial agent may be necessary if R. equi resistant to both agents is isolated.