ABSTRACT
Acknowledgments ........................................................... 480
References ........................................................................ 480
While a variety of bacteria have been isolated from various lesions in reptiles, in most situations they have been reported as causative agents of disease based simply upon isolation, on the body surface, within visceral structures, or in excretory products. While infections with Gram-positive bacteria do occur in reptiles, it appears that infections caused by Gram-negative bacteria are more common (Jacobson, 1987). Aeromonas, Citrobacter, Enterobacter, Escherichia, Morganella, Providencia, Pseudomonas, and Salmonella are just a few of a long list of aerobic bacteria frequently isolated from ill captive reptiles (Mayer and Frank, 1974; Jacobson, 1984a). These organisms appear to become more invasive when conditions either change the resistance of the host or select for pathogenic organisms. They may also become invasive following a primary viral disease, such as paramyxovirus pneumonia and chelonian herpesvirus stomatitis. Some groups of reptiles seem particularly prone to infection with specific types of bacteria. For instance, the American alligator (Alligator mississippiensis) is susceptible to Aeromonas hydrophila infections; Neisseria iguanae has been isolated from the oral cavity and bite wounds of the green iguana (Iguana iguana), and a chronic upper respiratory disease has been seen in the desert tortoise (Gopherus agassizii) and other tortoises, with Mycoplasma agassizii identified as a causative agent of this disease. Mycoplasma crocodyli and M. alligatoris have been identified as the cause of arthritis and pneumonia in Nile crocodiles (Crocodylus niloticus) and the American alligator, respectively. While mycobacterial diseases are not uncommon in reptiles, in most cases a diagnosis is based on identification of the organism in tissue section rather than isolation and specific identification. Infections with chlamydiae have now been identified in all major groups of reptiles. In this chapter the most important bacterial diseases of reptiles will be reviewed. Bacterial diseases will be first reviewed by pathogen. Because several different bacteria may be cultured from a lesion in a reptile, bacterial infection by certain systems will also be reviewed. For instance, aural abscesses are common in box turtles, and to a lesser degree in other turtles. While multiple bacteria have been identified in this lesion, the specific causative agent and pathogenesis have not been elucidated.
