Mycobacterium fortuitum: an iatrogenic cause of soft tissue infection in surgery.

BACKGROUND: Mycobacterium fortuitum is an uncommon cause of soft tissue infections. Treatment is often inadequate with persistence of infection unless the aetiological agent and its antibiotic sensitivity are accurately established. METHODS: Medical records of 23 patients with chronic soft tissue infection caused by M. fortuitum over a 12-year period from 1991 to 2002 were studied. RESULTS: In 20 patients the cause was iatrogenic, following intramuscular injections (12), laparoscopy (5) and other surgical procedures (3) and in three patients discharging sinuses developed spontaneously. Patients presented with recurrent abscesses or chronic discharging sinuses that did not respond to conventional surgical drainage. The diagnosis was established by isolating M. fortuitum from the tissues in all cases. The treatment consisted of a more aggressive surgical intervention in form of excision, debridement and extensive lay open with curettage and prolonged administration of appropriate antibiotics. The organism showed maximum sensitivity to amikacin and ciprofloxacin. Healing occurred in all cases. Three patients suffered recurrences: two responded to further debridement and antibiotics and are well at 2 and 5 years, respectively. CONCLUSION: A high index of suspicion based on clinical presentation is essential to diagnose M. fortuitum as a cause of soft tissue infection. Treatment involves aggressive surgical debridement and administration of combination antibiotics based on sensitivity, which should be continued for a period that will ensure complete healing and prevent recurrence.

Detecting mycobacteraemia for diagnosing tuberculosis.

BACKGROUND & OBJECTIVES: In human immunodeficiency virus (HIV) infected persons with pulmonary tuberculosis (TB), sputum may not always show acid fast bacilli (AFB). Moreover, in most cases of suspected extrapulmonary TB (irrespective of HIV status) mycobacteria-containing material is not readily available for investigation. This study evaluated whether blood culture for Mycobacterium tuberculosis bacteraemia (mycobacteraemia) help in diagnosing TB in such cases. METHODS: A total of 93 consecutive subjects with a clinical diagnosis of tuberculosis with or without laboratory confirmation, 42 with and 38 without coexisting HIV infection, and 13 patients with HIV infection without clinical evidence of TB were enrolled. Mycobacterial blood cultures were done using lysis centrifugation technique followed by subculturing onto the modified Lowenstein-Jenson medium (LJ-1) and Selective Kirchner's medium followed by subculturing onto the modified Lowenstein-Jenson medium (LJ-2, LJ-3). RESULTS: Of the 15 (16.2%) subjects with evidence of mycobacteremia in 4 (26.7%) blood was the first/ only source of diagnosing TB. Among 80 patients with clinical diagnosis of TB whether supported by laboratory tests or not, 14 (17.5%) had mycobacteraemia. Among the 21 HIV infected patients with laboratory proven TB, 9 (43%) had mycobacteraemia. INTERPRETATION & CONCLUSION: Blood culture appears to be a useful additional test to diagnose TB in persons with HIV infection. In patients without HIV infection, but with clinical picture compatible with TB, blood culture for mycobacteraemia may occasionally help in the diagnosis. We recommend the use of the lysis centrifugation technique followed by direct smear of the sediment along with inoculation of the sediment into both modified Lowenstein-Jenson medium and the Selective Kirchner's medium with subsequent subculturing onto the modified Lowenstein-Jenson medium for mycobacterial blood culture for detecting mycobacteraemia.