Sources of disseminated Mycobacterium avium infection in AIDS.
OBJECTIVE
To identify the sources of disseminated Mycobacterium avium complex (MAC) infection in AIDS.


METHODS
HIV positive subjects with CD4 counts <100/mm(3) in Atlanta, Boston, New Hampshire and Finland were entered in a prospective cohort study. Subjects were interviewed about potential MAC exposures, had phlebotomy performed for determination of antibody to mycobacterial lipoarabinomannin and for culture. Patient-directed water samples were collected from places of residence, work and recreation. Patients were followed for the development of disseminated MAC. Univariate and multivariate risk factors for MAC were analyzed.


RESULTS
Disseminated MAC was identified in 31 (9%) subjects. Significant risks in univariate analysis included prior Pneumocystis carinii pneumonia (PCP) (hazard ratio 1.821), consumption of spring water (4.909), consumption of raw seafood (34.3), gastrointestinal endoscopy (2.894), and showering outside the home (0.388). PCP, showering and endoscopy remained significant in a Cox proportional hazards model. There was no association between M. avium colonization of home water and risk of MAC. In patients with CD4<25, median OD antibody levels to lipoarabinomannin at baseline were 0.054 among patients who did not develop MAC and 0.021 among patients who did develop MAC (P=0.077).


CONCLUSIONS
MAC infection results from diverse and likely undetectable environmental and nosocomial exposures. Mycobacterial infection before HIV infection may confer protection against disseminated MAC in advanced AIDS.
von Reyn
C F
CF
Infectious Disease Section, Department of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA. c.fordham.von.reyn@hitchock.org
Arbeit
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Horsburgh
C R
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Ristola
M A
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Waddell
R D
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Tvaroha
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SM
Samore
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Hirschhorn
L R
LR
Lumio
J
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Lein
A D
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Grove
M R
MR
Tosteson
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D017088:AIDS-Related Opportunistic Infections / Q000150:complications* / Q000209:etiology / Q000382:microbiology / Q000635:transmission; D000163:Acquired Immunodeficiency Syndrome / Q000150:complications* / Q000382:microbiology; D015331:Cohort Studies; D016099:Endoscopy, Gastrointestinal / Q000009:adverse effects; D005260:Female; D005516:Food Microbiology; D006801:Humans; D008297:Male; D015269:Mycobacterium avium Complex; D015270:Mycobacterium avium-intracellulare Infection / Q000150:complications* / Q000209:etiology / Q000382:microbiology / Q000635:transmission; D016720:Pneumocystis Infections / Q000150:complications; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D017747:Seafood / Q000382:microbiology; D014871:Water Microbiology