BACILLUS-MYCOIDES - A BACTERIAL PATHOGEN OF CHANNEL CATFISH

Bacillus mycoides was isolated from channel catfish Ictalurus punctatu s during an epizootic in a commercial culture pond in Alabama, USA. Du ring the epizootic, the fish had pale areas or ulcers on the dorsum an d focal necrosis of epaxial muscle. Dissolved oxygen, ammonia, and oth er water characteristics were within normal ranges. Pathogens other th an B. mycoides were not found in the moribund fish. Histologic examina tion of the lesions revealed necrotic muscle with chains of Gram-posit ive bacilli. Intramuscular injection of 1.6 x 10(4) colony forming uni ts of B. mycoides into channel catfish caused lesions that resembled t hose in fish during the epizootic. Similar lesions developed after sub cutaneous injection of B. mycoides, but intraperitoneal injection or a pplication of B. mycoides to abraded skin did not result in lesions.