Mechanisms of Pathogenesis and Host Resistance to Nocardia

Beaman, Blaine L.

doi:10.1016/b978-0-12-528620-6.50011-2

Cited by 6 publications

(8 citation statements)

References 67 publications

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“…The mechanisms of pathogenesis have been studied extensively and have been shown to be multiple, complex, and not yet fully understood (60,67,68,74). The virulence of N. asteroides appears to be associated with its stage of growth and with its ability to inhibit phagosome-lysosome fusion, neutralize phagosomal acidification, resist oxidative killing mechanisms of phagocytes, alter lysosomal enzymes within phagocytes, and invade and grow within the brains of experimental animals (57, 58, 69, 71, 73, 84, 86, 98, 115-118, 208-210, 244).…”

Section: Discussionmentioning

confidence: 99%

“…The mechanisms of host resistance to nocardiae are also complex and not understood completely (60,69,74). Filice et al suggest that PMNs play a role in retarding the growth of the nocardial cells to permit adequate time for a cell-mediated immune response to develop, since activated macrophages are better able to kill nocardiae than are PMNs in vitro (242)(243)(244)(245)(246).…”

Section: Discussionmentioning

confidence: 99%

“…Only during the last 20 to 25 years has reliable and reproducible information about mechanisms of pathogenesis and host immunity to nocardial infections been forthcoming (56,60,64,67,74,93). One of the major problems that had to be solved was the development of a defined experimental animal model system that would allow careful and systematic investigation.…”

Section: Cns Nocardiosismentioning

confidence: 99%

“…N. otitidiscaviarum CDC 112 and N. asteroides GUH-2 were induced to grow as L-forms in vitro (62,63,65) and then injected either i.v. or intraperitoneally into mice (60,62). The animals were monitored for 1 year to assess the persistence of L-forms, the latency of disease, the induction of a pathologic response, the reversion of the L-forms to the normal walled cell type, and the induction of progressive disease (62).…”

Section: Role Of Mycolic Acids In Nocardia-host Interactionsmentioning

confidence: 99%

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Nocardia species: host-parasite relationships

1994

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The nocardiae are bacteria belonging to the aerobic actinomycetes. They are an important part of the normal soil microflora worldwide. The type species, Nocardia asteroides, and N. brasiliensis, N. farcinica, N. otitidiscaviarum, N. nova, and N. transvalensis cause a variety of diseases in both normal and immunocompromised humans and animals. The mechanisms of pathogenesis are complex, not fully understood, and include the capacity to evade or neutralize the myriad microbicidal activities of the host. The relative virulence of N. asteroides correlates with the ability to inhibit phagosome-lysosome fusion in phagocytes; to neutralize phagosomal acidification; to detoxify the microbicidal products of oxidative metabolism; to modify phagocyte function; to grow within phagocytic cells; and to attach to, penetrate, and grow within host cells. Both activated macrophages and immunologically specific T lymphocytes constitute the major mechanisms for host resistance to nocardial infection, whereas B lymphocytes and humoral immunity do not appear to be as important in protecting the host. Thus, the nocardiae are facultative intracellular pathogens that can persist within the host, probably in a cryptic form (L-form), for life. Silent invasion of brain cells by some Nocardia strains can induce neurodegeneration in experimental animals; however, the role of nocardiae in neurodegenerative diseases in humans needs to be investigated.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Cns Nocardiosismentioning

confidence: 99%

Section: Role Of Mycolic Acids In Nocardia-host Interactionsmentioning

confidence: 99%

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Nocardia species: host-parasite relationships

1994

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“…24), which has sometimes been the case (Harris 1979;Curry 1980). Aerobic actinomycetes, particularly nocardias, pass through coccoid-bacillary-filamentous-branching mycelia stages and return to the coccoid form to restart the cycle, during their various growth phases (Beaman 1979(Beaman , 1984Matthay & Greene 1980). The finding of any, or some, of these cell forms, suggests the presence of actinomycetes, probably nocardias.…”

Section: U L T U R E Smentioning

confidence: 99%

Presumptive diagnosis of pulmonary nocardiosis: value of sputum microscopy

Osoagbaka

Njoku-Obi

1987

Journal of Applied Bacteriology

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Three hundred samples of sputum from patients suffering from various forms of pulmonary disorders were homogenized by pancreatic digestion, examined microscopically and cultured on brain heart infusion agar, trypticase soy agar, in brain heart infusion broth, trypticase soy broth and McClung's carbon-free broth. Several elements of varying morphological forms, believed to be from aerobic actinomycetes or nocardias, were observed in 16 cases. Six strains of Nocardia asteroides, one N. brasiliensis, eight of Rhodococcus species and one Micromonospora were isolated and studied at various stages of growth. Several nocardial and rhodococcal elements closely resembling those observed in the Gram-stained sputa were found. It is suggested that some of those in the sputum were from nocardias and that their appearance in sputum, as seen from the Gram-stained slide, when combined with clinical symptoms can serve for a presumptive diagnosis of pulmonary nocardiosis pending a more definitive identification by a specialized laboratory.

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Effect of presensitization of Nocardia asteroides with specific antibody on the viability of the organism

Osoagbaka

1996

World Journal of Microbiology & Biotechnology

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Nocardia asteroides from various growth phases was treated in vitro with normal rabbit sera, immune rabbit sera containing nocardial polyclonal antibodies and a monoclonal antibody. At intervals, samples were grown in broth or on blood agar plates to determine their viability. Log and stationary phase cells were injected intra-peritoneally into female BALB/c mice and their survival rates in the liver and spleen were determined. Presensitization with antibodies reduced the viability of the log phase cells by 48% and that of the late stationary phase by 4%. The antibody-treated log phase organisms were less viable on the blood agar medium and in the spleen and liver than the control organisms. This indicates that pretreatment with antibody has a lethal effect on N. asteroides and affects its survival in vivo.

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Mechanisms of Pathogenesis and Host Resistance to Nocardia

Cited by 6 publications

References 67 publications

Nocardia species: host-parasite relationships

Nocardia species: host-parasite relationships

Presumptive diagnosis of pulmonary nocardiosis: value of sputum microscopy

Effect of presensitization of Nocardia asteroides with specific antibody on the viability of the organism

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