Recurrent Nonfatal Chromobacterium violaceum Infection
from Infections in Medicine ®
In 1905, Wooley first described C violaceum infection in studying dead and dying water buffalo in the Philippines. There have also been reports of the infection in other mammals, especially gibbons, pigs, and cattle. The first human infection was reported in Malaya in 1927. As stated previously, the organism is well known in the southeastern United States. It is a soil and water inhabitant, is abundant in tropical and subtropical freshwater, and is especially prevalent in water that is stagnant or slow-moving.[2,3,5] Infections have been reported in the southeastern and northeastern United States, Southeast Asia, and South America. Review of the literature and communication with the CDC indicate that there have been 24 reported cases in the United States, with a mortality rate of 73%. This case makes the 25th reported case, reducing the mortality rate to 64%.
Underlying defects in host defenses seem to predispose to infection. However, a number of cases have been described with no known host-factor dysfunction. There has been documentation of patients with chronic granulomatous disease and susceptibility to the infection.[2,5] The infection is usually acquired through trauma. The resulting infection can involve the urinary tract, GI tract, bloodstream, lung, abdominal cavity, or bone. Invasion can occur with or without an obvious primary focus.
The most common presentation is that of skin lesions and septicemia. Skin manifestations are secondary to systemic disease and include pustular dermatitis, cellulitis, and ulcerations.[2,5] Other dermatologic lesions include vesicles, ecchymotic maculae, maculopapular rash, subcutaneous nodules, lymphangitis, and digital gangrene.
Diagnosis is made by culture of the blood, abscess fluid, or exudate. There is no diagnostic serologic test. Gram stain may reveal a gram-negative, long bacillus that occasionally may have a slight curve, which may result in confusing the organism with Vibrio species. The organisms are facultatively anaerobic and grow readily in 18 to 24 hours on tryptophan medium. Incubation at 30°C to 45°C (86°F to 113°F) is effective, although growth is enhanced at 25°C (77°F). Microbiologists may regard the culture as a contaminant when it is isolated or may dismiss the nonpigmented form as a less virulent organism. This can be a costly error.
The organism is usually susceptible in vitro to chloramphenicol, tetracycline, TMP-SMX, and gentamicin. It is variably sensitive to penicillins and aminoglycosides but is resistant to most cephalosporins. Erthromycin seems to be ineffective in vivo regardless of susceptibility testing. The optimal antibiotic regimen is not known. Some studies advocate the use of parenteral antibiotics for an extended period, followed by at least 4 weeks with an oral agent, such as TMP-SMX or tetracycline, to prevent relapse. Relapse has occurred more than 2 weeks after completion of therapy and apparent cure. The disease is usually fatal if not diagnosed and treated with appropriate antibiotics and debridement at the earliest possible time. Clinicians should therefore be vigilant for the possibility of relapse or apparent reinfection, as in the above case.
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