Search

Nocardia transvalensis, a rare Nocardia species, has previously been recognized as a cause of actinomycotic mycetoma. In a retrospective review of N. transvalensis isolates referred to the Centers for Disease Control (Atlanta) during the period January 1981 through January 1990, we identified 15 patient isolates. Four N. transvalensis isolates originated from one Australian reference laboratory; one patient's isolate that was identified by the Australian laboratory but that was not received at the Centers for Disease Control was also included in our study. A review of the cases of these 16 patients found that N. transvalensis caused infection in 10 patients and colonization in two patients. Six (75%) of eight patients with primary pulmonary or disseminated N. transvalensis infections had an underlying immunologic disorder or were receiving immunosuppressive therapy; three patients with disseminated infection died. All nine infected patients for whom specific antimicrobial therapy was prescribed received trimethoprim-sulfamethoxazole. Results of in vitro antimicrobial susceptibility tests of 11 N. transvalensis isolates revealed increased antimicrobial resistance to amikacin and other drugs when compared with that of other Nocardia species. Severely immunocompromised patients are predisposed to N. transvalensis pneumonia or disseminated infection, and the lung may be the portal of entry.

Objective: To review the species distribution, pathologic significance and disease associations of clinical isolates of Nocardia and related bacteria in Queensland, and to examine the characteristics, treatment and outcome of patients infected with these organisms., Design and Setting: A retrospective review of Queensland State Health Laboratory records provided microbiological data for Nocardia isolates referred from other laboratories during the period January 1983 to December 1988. Clinical information was extracted from hospital case notes, or obtained from detailed questionnaires completed by attending physicians. Nocardia isolates were classified as "significant" if specific treatment for nocardiosis was given, or on the basis of autopsy findings., Patients: One hundred and two patients had a Nocardia species or a related organism isolated from clinical specimens during the study period., Results: The 102 isolates included Nocardia asteroides (45), N, brasiliensis (35), N. caviae (5) and N. transvalensis (5). Clinical results were available for 93 patients, of whom 74 (80%) had a significant isolate recovered. Primary pulmonary or disseminated disease occurred in 35 patients, and was caused mainly by N. asteroides. Significant infections of skin and soft tissues, primarily due to N. brasiliensis, were found in 39 patients. Preexisting lung disease and treatment with steroids and immunosuppression were risk factors for pulmonary and disseminated nocardiosis. A history of inoculation in an outdoor setting was frequent in patients with cutaneous disease. Antibiotic regimens that included trimethoprim-sulfamethoxazole or another sulfonamide agent were used to treat the majority of patients with significant infection. Deaths were confined to those with pulmonary and disseminated disease, with a case fatality rate of 40% in that group., Conclusion: Infection with Nocardia species appears to be more common than is generally appreciated. The local species distribution and disease spectrum are similar to those described elsewhere. A high index of suspicion for nocardiosis should be maintained in susceptible hosts with pulmonary infiltrates, particularly when there is evidence for metastatic infection, and in patients with superficial infections and a history of outdoor injury.