Mycobacterium asiaticum as the probable causative agent in a case of olecranon bursitis.

Mycobacterium asiaticum was isolated from fluid aspirated from an olecranon bursa that had become inflamed following a superficial injury. Other possible causes of the inflammation were excluded. No specific antimycobacterial therapy was given. The infection responded to drainage, regular dressing, and immobilization. Our experience suggests that M. asiaticum is a potential cause of infection of the joints and surrounding tissues.

Infections due to Nocardia transvalensis: clinical spectrum and antimicrobial therapy.

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.

Infection with Nocardia species in Queensland. A review of 102 clinical isolates.

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.

Human disease due to Mycobacterium smegmatis.

Mycobacterium smegmatis is a rapidly growing environmental species not considered a human pathogen. We identified 22 human isolates of M. smegmatis from Australia and the southern United States: 19 were from skin or soft-tissue infections, and none were from urine or the male genital tract. These isolates closely resembled Mycobacterium fortuitum, except for a negative three-day arylsulfatase test; growth at 43-45 C; a low semiquantitative catalase test; and, in 50% of isolates, a late-developing, yellow-to-orange pigment. The isolates were biochemically identical to four reference strains and the type strain of M. smegmatis. Isolates were resistant to isoniazid and rifampin but susceptible to ethambutol, doxycycline, sulfamethoxazole, ciprofloxacin, imipenem, and amikacin. Eleven patients treated on the basis of in vitro susceptibility tests responded well to therapy. The similarity of M. smegmatis to M. fortuitum and the failure to recognize that the former is an environmental species may have contributed to previous failures to recognize it as a human pathogen.

Bacteremia caused by Mycobacterium neoaurum.

An immunocompromised patient with an indwelling Hickman catheter developed Mycobacterium neoaurum bacteremia. This rapidly growing mycobacterium was previously isolated from soil, dust, and water but has not been described as a human pathogen. The infection responded to therapy with cefoxitin and gentamicin. It was not necessary to remove the Hickman catheter.

Mycobacterium asiaticum as a potential pulmonary pathogen for humans. A clinical and bacteriologic review of five cases.

Mycobacterium asiaticum was isolated from pulmonary material from 5 persons residing in Queensland, Australia. All patients had repeated positive specimens, but the organism was considered responsible for pulmonary mycobacteriosis in only 2 of them. This is the first report of disease caused by M. asiaticum. Clinical, bacteriologic, and epidemiologic details are presented.

Mycobacterial cross-contamination of bronchoscopy specimens.

Bronchoscopy specimens from 3 patients investigated during 1 wk at a large teaching hospital were culture positive for the same serovar of Mycobacterium intracellulare. Review of laboratory records and patient data suggested that only the first patient examined was a genuine excretor of mycobacteria; the isolates from the other 2 patients were false positives caused by inadequate disinfection of part of the collection apparatus between use. The investigations confirm the suitability of glutaraldehyde as a rapid, highly effective antimycobacterial disinfectant and illustrate the value of serotyping when dealing with mycobacterial isolates of questionable significance.

Differential identification of mycobacteria in smears of sputum.

As a test of their ability to differentiate mycobacteria in Ziehl-Neelsen stained smears of sputum, 4 readers examined an assortment of 200 smears, of which half were known to contain Mycobacterium tuberculosis and half were known to contain atypical mycobacteria. In 2 separate trials, readers made a prediction of either 'typical' or 'atypical' for each smear. Reader consistency between trials ranged from 69.5% to 86.5%, indicating that readers were basing their predictions on definite criteria. Overall accuracy ranged from 62.5% to 80%, with experienced readers being the most accurate. Reliability of readers' predictions was influenced by smear positivity, but certain smears exhibited uncharacteristic features which led to incorrect predictions. When considered along with other available data, smear-based presumptive diagnosis can assist the clinician in his management of the patient with suspected tuberculosis in the period before culture results are known.

Misleading results from bone marrows cultured for mycobacteria.

Re-evaluation of a previous study dealing with atypical mycobacteria grown from specimens of bone marrow provided strong evidence that the isolates were of no clinical significance. Bone marrow culture should not be undertaken as a diagnostic test for pulmonary atypical mycobacteriosis.

Mycobacterium haemophilum causing lymphadenitis in an otherwise healthy child.

Suppurating submandibular lymphadenitis in an otherwise healthy infant was caused by Mycobacterium haemophilum, A fastidious organism which requires media supplemented with ferric ammonium citrate or haemoglobin for its growth. It is recommended that material from superficial lesions and lymph nodes collected for mycobacteriological investigations be cultured on media known to support growth of M. haemophilum.

Atypical mycobacteria causing non-pulmonary disease in Queensland.

During the period 1971--7, the Tuberculosis Reference Laboratory in Queensland dealt with 52 isolates of atypical mycobacteria made from non-pulmonary sites under circumstances suggesting complicity in disease. Twenty-four isolates belonging to the MAIS complex were associated with lymph node infections in children. Twelve isolates belonged to the M. fortuitum-chelonei complex; most were from superficial abscesses. Five cases of M. marinum infection and 8 of M. ulcerans disease were detected.

Mycobacterium avium associated with chronic pulmonary disease in a Queensland resident.

Bacteriological investigation over an 11-year period has implicated Mycobacterium avium ser I as the most probable cause of chronic pulmonary disease in a resident of south-eastern Queensland. Although the patient had contact with domestic fowls and a pet budgerigar, the source of the organism is uncertain.

Serum agglutinins in disease caused by Mycobacterium intracellulare.

Serum from each of five persons with pulmonary mycobacteriosis due to Mycobacterium intracellulare contained agglutinins specific for the serotype of the causative organism. The findings suggest that the direct agglutination test may prove useful in diagnostic mycobacteriology.