Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA), a chronic contagious disease in small ruminants. The prevalence of CLA has been reported to be >50% in Korean black goats. CLA is difficult to control due to a lack of efficient vaccines and treatment methods. Effective disinfection of the farm environment may be an alternative strategy for reducing the spread of C. pseudotuberculosis. The objective of this study was to evaluate the efficacy of commercial disinfectants against CLA. The six commercial disinfectants, largely composed of sodium dichloroisocyanurate, sodium hypochlorite, potassium monopersulfate triple salt, quaternary ammonium, citric acid, and copper sulfate, were tested against five different genotypes of C. pseudotuberculosis isolated from goat farms in Korea. Efficacy tests were performed in accordance with the disinfectant efficacy test guidelines recommended by the Animal and Plant Quarantine Agency of Korea with slight modifications. All disinfectants except for copper sulfate exhibited >99.99% killing efficacy under hard water conditions following 30 min of incubation, which is the recommended standard treatment time according to guidelines. The minimum bactericidal treatment time was evaluated by employing treatments for durations of 1, 5, and 15 min. The most effective compounds under hard water conditions were sodium dichloroisocyanurate, potassium monopersulfate triple salt, and sodium hypochlorite, exhibiting >99.99% killing efficacy after 1 min of treatment. In the aqueous solution forms, citric acid and the quaternary ammonium compound were the most effective, but required at least 5 min to kill >99.99% of the bacteria. The current study characterizes the killing efficacy of six commercial disinfectant active compounds against C. pseudotuberculosis. Thus, this study provides essential information regarding the efficacy of the disinfectants used to control CLA in goat farms.

A case of caseous lymphadenitis (CL) was detected in a native Korean goat without manifestation of superficial nodules but with pulmonary abscesses that were characterized microscopically by granulomatous inflammation consisting of a central necrotic region, peripheral fibrous capsule, and numerous cellular infiltrates with epithelioid macrophages, giant cells, and lymphocytes. Presence of Corynebacterium pseudotuberculosis was identified by using bacterial isolation and multiplex PCR. In addition, a 43% seropositivity to C. pseudotuberculosis was observed in goats from the same farm. This case highlights the risk of exposure of farmers to the causative agent and the urgent need for national monitoring for CL, a potential zoonotic.