A Pasteurella sp associated with respiratory disease in captive desert tortoises

Bacteria isolated from captive healthy desert tortoises were compared with bacteria from captive tortoises with respiratory illness and with bacteria from free-ranging tortoises from the Mojave Desert. Major differences were not observed among these groups when bacteria from the mouth, nares, trachea, lungs, and cloaca were compared. Frequently encountered organisms in all 3 groups included: coagulase-negative, catalase-positive, gram-positive cocci; Corynebacterium sp; members of Enterobacteriaceae, including Proteus spp; and a bacterium apparently belonging to the genus Pasteurella. The Pasteurella sp was consistently found to be associated with respiratory lesions in captive tortoises with signs of respiratory disease but was also found to be part of the gastrointestinal and nasal flora of healthy tortoises. It was hypothesized that respiratory disease in captive desert tortoises involves a commensal bacterium with the potential to be an opportunistic pathogen when the tortoise is stressed by a captive environment.