Mycobacterium avium-Mycobacterium intracellulare from the Intestinal Tracts of Patients with the Acquired Immunodeficiency Syndrome: Concepts Regarding Acquisition and Pathogenesis

Damsker, B; Ej, Bottone

doi:10.1093/infdis/151.1.179

Cited by 158 publications

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“…Sufficient evidence exists to suggest that the gastrointestinal (GI) tract is the major route of infection in patients with AIDS [4], although the respiratory tract appears to be the route of infection in a small percentage of cases [5]. Therefore, a critical step in the pathogenesis of M. avium infection is the crossing of the intestinal mucosa.…”

Section: Introductionmentioning

confidence: 99%

Ultrastructural study of Mycobacterium avium infection of HT-29 human intestinal epithelial cells

Sangari¹,

Goodman

Bermudez³

2000

Journal of Medical Microbiology

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Mycobacterium avium is a common pathogen in AIDS patients and, in a large percentage of those patients, M. avium infection appears to be acquired via the gastrointestinal tract. M. avium is able to bind to and enter human and murine intestinal epithelial cells in vitro and in vivo. The invasion by and intracellular fate of M. avium in the HT-29 intestinal epithelial cell line was examined in an ultrastructural study. Bacterial contact with polarised cells was observed 10-15 min after monolayer infection and in polarised monolayers this always occurred in areas lacking microvilli. Contact with HT-29 cells did not appear to take place in a preferential area on the bacterial cell. Following invasion, M. avium was encountered within vacuoles containing either single or multiple bacteria; the latter evolved to contain only an individual bacterium. Vacuoles containing more than one bacterium were seen early in the infection and eventually underwent segmentation, with each bacterium occupying a vacuole. No bacteria were observed outside vacuoles up to 5 days after infection.

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Section: Introductionmentioning

confidence: 99%

Ultrastructural study of Mycobacterium avium infection of HT-29 human intestinal epithelial cells

Sangari¹,

Goodman

Bermudez³

2000

Journal of Medical Microbiology

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“…The pattern of disease suggests that infection occurs via the gastrointestinal tract rather than by the respiratory route. l 4 Infection is frequently associated with abdominal pain, diarrhoea and malabsorption. Large numbers of MA1 organisms may be found in faeces and in biopsy tissue from the gastrointestinal tract, and the recovery of MA1 from these specimens has been correlated with invasive disease.2"…”

Section: Introductionmentioning

confidence: 99%

Plasmid analysis of Mycobacterium avium-intracellulare (MAI) isolated in the United Kingdom from patients with and without AIDS

Hellyer

Brown²,

Dale³

et al. 1991

Journal of Medical Microbiology

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Summary. One hundred and forty-seven isolates (1 28 strains) of Mycobacterium aviumintracellulare (MAI) were screened by agarose gel electrophoresis for the presence of plasmids. Plasmids were characterised according to size and by Southern hybridisation analysis of intact and restriction endonuclease-digested DNA. Two cloned MA1 plasmids, pLR7 and pLR20, were used as probes. There was no significant difference in the rate of plasmid carriage in MA1 strains isolated from patients with the acquired immuno-deficiency syndrome (AIDS) and from non-AIDS patients in the UK, but a higher rate of plasmid carriage was observed in a panel of American strains from AIDS patients. Plasmids were grouped into two broad categories: small (mostly 14-30 kb) and large (> 150 kb). Southern blot analysis identified two distinct groups of small plasmids, the majority of which showed homology with pLR7. Plasmids from this group were significantly more common in strains of serotypes 4 and 8 which are particularly associated with AIDS.

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“…HIV-1-immunocompromised individuals may acquire M. avium through the intestinal tract where it translocates across the mucosa to enter submucosal macrophages in the lamina propria (11,12). From the mucosa, dissemination may then occur to a variety of susceptible tissues.…”

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Mycobacterium aviumInfection and Modulation of Human Macrophage Gene Expression

Greenwell-Wild

Vázquez

Sim

et al. 2002

The Journal of Immunology

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Mycobacterium avium is a facultative intracellular pathogen cleared rapidly via intact host defense mechanisms. In the absence of adequate T cell function, as occurs in HIV-1-induced immunodeficiency, M. avium becomes an opportunistic infection with uncontrolled replication and reinfection of macrophage hosts. How M. avium infects, survives, and replicates in macrophages without signaling an effective microbicidal counterattack is unresolved. To address whether M. avium signals the expression of molecules, which influence mycobacterial survival or clearance, human monocyte-derived macrophage cultures were exposed to M. avium. Within minutes, M. avium, or its cell wall lipoarabinomannan, binds to the adherent macrophages and induces a spectrum of gene expression. In this innate response, the most abundant genes detected within 2 h by cDNA expression array involved proinflammatory chemokines, cytokines including TNF-α and IL-1, and adhesion molecules. Associated with this rapid initial up-regulation of recruitment and amplification molecules was enhanced expression of transcription factors and signaling molecules. By 24 h, this proinflammatory response subsided, and after 4 days, when some bacteria were being degraded, others escaped destruction to replicate within intracellular vacuoles. Under these conditions, inducible NO synthase was not up-regulated and increased transferrin receptors may facilitate iron-dependent mycobacterial growth. Sustained adhesion molecule and chemokine expression along with the formation of multinucleated giant cells appeared consistent with in vivo events. Thus, in the absence of T lymphocyte mediators, macrophages are insufficiently microbicidal and provide a nonhostile environment in which mycobacteria not only survive and replicate, but continue to promote recruitment of new macrophages to perpetuate the infection.

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Mycobacterium avium-Mycobacterium intracellulare from the Intestinal Tracts of Patients with the Acquired Immunodeficiency Syndrome: Concepts Regarding Acquisition and Pathogenesis

Cited by 158 publications

References 0 publications

Ultrastructural study of Mycobacterium avium infection of HT-29 human intestinal epithelial cells

Ultrastructural study of Mycobacterium avium infection of HT-29 human intestinal epithelial cells

Plasmid analysis of Mycobacterium avium-intracellulare (MAI) isolated in the United Kingdom from patients with and without AIDS

Mycobacterium aviumInfection and Modulation of Human Macrophage Gene Expression

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