Disseminated Mycobacterium fortuitum Infection Associated with Venous Access Device.

Mycobacterium fortuitum is an important opportunistic pathogen among the rapidly growing Mycobacteria. Disseminated disease occurs as a consequence of bacteremia linked to vascular catheters, which carry high morbidity and mortality when they occur in immuno-compromised patients. Conventional culture methods often miss these organisms since they may grow more slowly (after 48 h) and are dismissed as skin contaminants because of their morphological resemblance to diphtheroids on grams staining. We report a case of 10 months old child with primitive neuroectodermal tumor who developed disseminated disease with M. fortuitum that was related to an indwelling intravascular device. The isolates were confirmed as M. fortuitum by polymerase chain reaction based DNA sequencing targeting heat shock protein 65 gene. The child was treated with, rifampicin, ethambutol and azithromycin. The patient improved remarkably and became afebrile 2 days after institution of therapy and removal of the catheter. The treatment was given for 3 months.

Rapidly growing mycobacterial infections: spectrum of diseases, antimicrobial susceptibility, pathology and treatment outcomes.

OBJECTIVES: A series of cases infected with rapidly growing mycobacteria were studied to reveal the spectrum of disease, antimicrobial susceptibility, pathology, and treatment outcomes. METHOD: The cases identified as rapidly growing mycobacterial infections in Ramathibodi Hospital from January 1993 to June 1999 were retrospectively studied. RESULTS: There were 20 patients and most of the cases had no underlying disease. Only two cases were HIV-infected patients. The presenting clinical features were lymphadenitis (7), skin and subcutaneous abscess (7), eye infection (4), pulmonary infection (1), and chronic otitis media (1). Four of the seven cases with lymphadenitis had Sweet's syndrome. The organisms were Mycobacterium chelonae/abscessus group (17 cases) and Mycobacteriumfortuitum group (3 cases). The organisms were susceptible to amikacin, netilmicin and imipenem. The M. fortuitum group was susceptible to more antibiotics than the M. chelonaelabscessus group. Pathology of the infected tissue varied from non-specific findings to suppurative or caseous granuloma. The clinical responses corresponded to the antimicrobial susceptibility. Most of the patients had a good clinical outcome. A combination of two or more drugs was used for the medical treatment. Surgical resection was performed where possible to reduce the load of the organism, especially in cases with very resistant organisms. CONCLUSIONS: Rapidly growing mycobacterial infections can occur in apparently normal hosts. Clinical syndrome is variable. The pathology is non-specific and culture is needed for definite diagnosis. Clinical responses varied but seemed to correlate with the in vitro susceptibility result. More studies are needed before one can deal with these infections more effectively.