In amphibians bacterial infections are commonly caused by gram-negative bacteria, such as Aeromonas, Pseudomonas, Proteus, and E. coli. Poor husbandry, (e.g., overcrowding, poor water quality, inappropriate cage design or setup, spoiled food, exposure to toxins such as pesticides) may allow one of these bacteria to overwhelm amphibian's immunologic defenses.
Aeromonas is the most common cause of clinical bacterial diseases in amphibians and has been associated with the syndrome known as redleg disease. Once the first warning signs are noticed, (e.g., reddening of the under-skin, loss of appetite) appropriate antibacterial therapy is necessary. Treatment will depend on the exact pathogen that has been cultured and definitely identified. The first thing to do, however, is to isolate the affected animal.
Acute septicemia can occur if warning signs are unnoticed or untreated. Clinical signs may be brief and extremely rapid in chronology. Bloating, ascites, anorexia, lethargy, and sometimes open sores, may be noted shortly before the onset of convulsions and sudden death. Blood hemorrhages beneath the skin may be present up to several hours a before death or may appear immediately prior to or during the agonizing convulsions. Post-mortem lesions are consistent with blood clots in the veins, spleen, and liver. Culture of the blood and internal organs of the dead animal is sanctioned to determine the pathogen if it has not been already. If caught in time, redleg disease can be treated and cured. Oral tetracycline treatment should be initiated immediately. An aminoglycosides treatment may also be helpful.
Once the pet has reached the final stages of the disease, he may have open sores on his back and legs. An antibiotic ointment such as Tritop or Neosporin may be used to promote healing of skin tissues and prevent secondary infections. A tetracycline bath is helpful in some cases, but not many. Many owners use the products Reptoheal™ or Newskin™, but these can actually cause further damage to the skin tissue and should never be used on an open wound.
Mycobacteria can also cause skin lesions and open sores in amphibians. The bacterium is generally waterborne but some are soil saprophytes (e.g., Mycobacterium marinum, M. ranae, M. xenopi). In contrast to the more common bacterial infections, amphibians with mycobacterial infections show rapid weight loss despite a good appetite.
If open sores are present, diagnostics should include an examination of a skin scraping or biopsy to determine if acid-fast organisms are present. However, culturing of the mycobacterial agent does not alter the patient's prognosis, but may be important to determine if the agent is likely to be zoonotic. As in the treatment for redleg disease, the exact pathogen has to be identified before appropriate treatment can be begun. Tetracycline is often prescribed, and an antibiotic ointment, such as Tritop or Neosporin™ is used on the sores.
Unfortunately, an exploratory laparotomy or laproscopy may be necessary to detect similar lesions in the organs of the affected amphibian. If these lesions are found, euthanasia is normally recommended to prevent a grueling, agonizing death of the pet.
It hasn't been proven, but some veterinarians and herpetologists believe that mycobacterial infections can soon follow redleg disease. Of the cases of mycobacterial infected amphibians, 85 to 90% of the animals had had redleg disease in the past three to nine months. Investigations are being conducted to determine if the link is coincidental or if the mycobacterial infection is a secondary infection.


Special thanks to Crystal Parker for providing this information.

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