Abstract
Mycobacterium genavense is a relatively new species of nontuberculous mycobacterium reported to cause disseminated infections in patients with AIDS and later on in non-HIV immunosuppressed patients. We describe clinical and laboratory features and response to therapy in 7 patients, three of them with HIV infection and four non-HIV—three organ transplant recipients and one with hyper-IgE syndrome—in Valencia, Spain, in a ten years period. We then summarize the published cases of M. avium complex infection, with invasion of peripheral blood, liver, spleen, bone marrow, lymph nodes, and lungs. In clinical samples a large number of acid-fast bacilli were observed. M. genavense grew only from liquid media and after a prolonged incubation period. Its identification was accomplished through molecular methods. Patients were treated with prolonged combinations of antimicrobial agents. There was clinical favourable outcome in 4 patients.
Highlights
Mycobacterium genavense is a nontuberculous mycobacterium (NTM), first described in 1990 [1], proposed as a new species in 1992 [2, 3], and characterized in 1993 [4]
Symptoms vary from nonspecific in otherwise healthy patients to disseminated symptomatology in immunosuppressed ones. These are similar to those observed in Mycobacterium avium complex (MAC) infection and can include fever, abdominal pain, diarrhea, weight loss, lymphadenitis, hepatosplenomegaly, and progressive anemia, being the bowel the most affected organ [17]
The samples were cultured in two Lowenstein-Jensen (LJ) solid media and liquid media: either BACTEC 12B Mycobacteria Medium which contains 4 mL of Middlebrook 7H12 to be periodically measured in the BACTEC 460TB radiometric instrument until 2008 or the BBL Mycobacteria Growth Indicator Tube (MGIT) with 7 mL modified Middlebrook 7H9 with the BD MGIT 960 automated fluorometric system, from that year onwards
Summary
Mycobacterium genavense is a nontuberculous mycobacterium (NTM), first described in 1990 [1], proposed as a new species in 1992 [2, 3], and characterized in 1993 [4]. No human to human transmission has been demonstrated It can cause infection in birds—it is the most frequently isolated mycobacterium in parrots and parakeets [11, 12]—and humans [13,14,15,16]. In the latter, symptoms vary from nonspecific in otherwise healthy patients to disseminated symptomatology in immunosuppressed ones. Its tendency to colonize the small intestine suggests that the digestive tract could act as a reservoir and that transmission could be oral or intestinal [10]
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