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At least 523 records · Page 29Linked to original sources
PubMed1988

Effect of intravenous silica on the course of Nocardia asteroides pneumonia.

Silica, a known toxin of mononuclear phagocytes, was administered intravenously to mice during Nocardia asteroides pneumonia. Mice that received silica had a sevenfold decrease in the number of peripheral blood monocytes and developed more severe N. asteroides pneumonia than control mice. Lung histology in mice that received silica resembled that of mice with impaired cell-mediated immunity. These results are most consistent with the explanation that silica injures blood monocytes and impairs their contributions to pulmonary host defense.

Animals↗
PubMed1993

Ultrastructural analysis of attachment to and penetration of capillaries in the murine pons, midbrain, thalamus, and hypothalamus by Nocardia asteroides.

The attachment to and penetration of endothelial cells in the pons and midbrain (especially the substantia nigra) regions of the brains of BALB/c mice by log-phase Nocardia asteroides GUH-2 cells were determined by both scanning and transmission electron microscopic analysis. Within 15 min after exposure, the nocardiae attached to the surface of the endothelial cell membrane. This attachment occurred primarily at the growing tip of the nocardial filament, and the outermost layer of the nocardial cell wall had regions (electron-dense areas) that bound firmly to the cytoplasmic membrane of the host cell. There appeared to be specificity for this binding localized within the capillaries and arterioles because some regions had large numbers of bacteria bound, whereas adjacent areas had no bacterial cells. Nocardial filaments that attached by the apex induced a cuplike deformation of the endothelial cell membrane. This was followed by a rapid penetration of the endothelial cell so that within 25 min many of the bacteria were internalized within the host cell. These internalized bacteria remained within vesicles, and there was no ultrastructural evidence of damage to the nocardial cell during this process. Heat-killed GUH-2 cells still attached to endothelial surfaces (at a reduced frequency), but they did not penetrate into the endothelial cell. These data suggest that brain-invasive nocardiae possess both an adhesin for attachment to the membrane of endothelial cells and an invasion factor that promotes nocardial penetration of these cells.

Animals↗
PubMed1998

Filament tip-associated antigens involved in adherence to and invasion of murine pulmonary epithelial cells in vivo and HeLa cells in vitro by Nocardia asteroides.

The interactions of Nocardia asteroides GUH-2 with pulmonary epithelial cells of C57BL/6 mice and with HeLa cells were studied. Electron microscopy demonstrated that only the tips of log-phase cells penetrated pulmonary epithelial cells following intranasal administration, and nocardiae were recovered from the brain. Coccobacillary cells neither invaded nor disseminated. Serum from immunized mice (IMS) decreased attachment to and penetration of pulmonary epithelial cell surfaces by log-phase GUH-2 and inhibited spread to the brain. IMS was adsorbed against stationary-phase cells. Western immunoblots suggested that this adsorbed IMS was reactive primarily with 43- and 62-kDa proteins. Immunofluorescence showed that adsorbed IMS preferentially labeled the tips of log-phase GUH-2 cells. Since this IMS was reactive to culture filtrate antigens, several of these proteins were cut from gels, and mice were immunized. Sera against 62-, 55-, 43-, 36-, 31-, and 25-kDa antigens were obtained. The antisera against the 43- and 36-kDa proteins labeled the filament tips of GUH-2 cells. Only the antiserum against the 43-kDa antigen increased pulmonary clearance, inhibited apical attachment to and penetration of pulmonary epithelial cells, and prevented spread to the brain. An in vitro model with HeLa cells demonstrated that the tips of log-phase cells of GUH-2 adhered to and penetrated the surface of HeLa cells. Invasion assays with amikacin treatment demonstrated that nocardiae were internalized. Adsorbed IMS blocked attachment to and invasion of these cells. These data suggested that a filament tip-associated 43-kDa protein was involved in attachment to and invasion of pulmonary epithelial cells and HeLa cells by N. asteroides GUH-2.

Animals↗
PubMed1963

IMMUNOLOGICALLY ACTIVE POLYSACCHARIDES FROM NOCARDIA ASTEROIDES AND NOCARDIA BRASILIENSIS.

Zamora, A. (University of Mexico, Mexico, D.F.), L. F. Bojalil, and Fernando Bastarrachea. Immunologically active polysaccharides from Nocardia asteroides and Nocardia brasiliensis. J. Bacteriol. 85:549-555. 1963.-Two immunologically active polysaccharides were isolated from Nocardia asteroides (Poly I Na and Poly II Na) and N. brasiliensis (Poly I Nb and Poly II Nb). These polysaccharides were isolated from cell extracts and purified by methanol precipitation, chloroform extraction of extraneous material, and deproteinization with trichloroacetic acid. The crucial step used for separation of Poly I and Poly II from both nocardias was differential solubility. From dried preparations containing both polysaccharides, Poly I was solubilized at pH 10, whereas Poly II remained insoluble and was subsequently solubilized at pH 5. Poly I Na and Poly I Nb are apparently the same. Arabinose and galactose were the monosaccharide constituents of these polysaccharides, and their molar ratios were similar. Furthermore, Poly I Na and Poly I Nb cross-reacted in agar diffusion precipitin tests with rabbit antisera prepared against either N. asteroides or N. brasiliensis. Either polysaccharide absorbed serum antibodies against the other. These polysaccharides can be regarded as groupspecific. Poly II Na and Poly II Nb are different and species-specific. They are composed of arabinose, galactose, and mannose but exhibit different molar ratios of these sugars according to species. They reacted only with homologous antisera.

Allergy and Immunology↗
PubMed1987

Comparison of paraffin baiting and conventional culture techniques for isolation of Nocardia asteroides from sputum.

Of 1,510 sputum samples examined from 1,016 patients with bronchopulmonary disorders, Nocardia asteroides was isolated from 67 samples by paraffin baiting, as compared with only 30 isolations by the conventional technique of culturing on Sabouraud dextrose agar. This higher efficacy of the paraffin bait technique was found to be statistically significant (P less than 0.001).

Bacteriological Techniques↗
PubMed1987

Peritonsillar abscess caused by Nocardia asteroides.

A 22-year-old man with recurrent pharyngitis developed a peritonsillar abscess from which aspirated material yielded a pure culture of Nocardia asteroides. It is likely that the organism was introduced iatrogenically during a prior tonsillar incision. Although unusual, Nocardia species should be considered and microbiological specimens should be handled appropriately in pharyngeal abscesses that respond poorly to conventional therapy.

Adult↗
PubMed1990

Monoclonal antibodies to Nocardia asteroides and Nocardia brasiliensis antigens.

Nocardia asteroides and Nocardia brasiliensis whole-cell extracts were used as antigens to generate monoclonal antibodies (MAbs). Six stable hybrid cell lines secreting anti-Nocardia spp. MAbs were obtained. These were characterized by enzyme-linked immunosorbent assay, Western blot (immunoblot), and immunofluorescence assay. Although all the MAbs exhibited different degrees of cross-reactivity with N. asteroides and N. brasiliensis antigens as well as with culture-filtrate antigens from Mycobacteria spp., they have the potential for use as reagents in the purification of Nocardia antigens.

Antibodies, Bacterial↗
PubMed1990

Cultivation of Nocardia spp. on chemically defined media for selective recovery of isolates from clinical specimens.

Isolation of Nocardia spp. from clinical specimens can be enhanced by the use of paraffin baiting, which relies on the selective ability of the organism to metabolize paraffin. We evaluated 44 Nocardia isolates, 18 group IV mycobacterial isolates, and 4 Streptomyces isolates for growth on blood agar (BA) and on carbon-free agar containing single or double substrates as follows: paraffin agar (PA), gelatin agar (GA), urea agar (UA), PA-gelatin (PG), and PA-urea (PU). The growth rates of Nocardia spp. on BA, PA, PU, and PG were similar; but 3-day-old colonies were larger on BA for 20 (45%) isolates. After longer incubations (7 to 14 days), some Nocardia colonies were larger on PA, PG and PU than they were on BA. Despite variable morphologies on BA, colonies on PA, PG, and PU were consistently smooth, creamy, and raised. Compared with growth on BA, the growth of mycobacteria was much slower on PA, PG, and PU, with poor growth on UA and GA. The growth of Streptomyces spp. was greatly enhanced on GA, PG, UA, and PU and was poorest on PA. Twelve sputum specimens seeded with Nocardia asteroides (10(4) CFU/ml) were inoculated onto BA and all chemically defined media. Nocardiae were recovered from 6 to 12 specimens grown on BA, GA, and UA; 11 of 12 specimens grown on PG; and 12 of 12 specimens grown on PA and PU. Only PA was able to suppress the growth of other microorganisms that were present in sputum specimens. These results suggest that chemically defined media containing PA may be useful for the selective isolation of Nocardia spp. from contaminated clinical specimens.

Culture Media↗
PubMed1990

Urease-negative Nocardia asteroides causing cutaneous nocardiosis.

We report a case of cutaneous nocardiosis, caused by a urease-negative strain of Nocardia asteroides, in a patient who had undergone long-term corticosteroid therapy. The microbiological characteristics of the isolate were typical of N. asteroides except for the failure of the isolate to hydrolyze urea. During the course of routine identification, laboratory specialists should be aware of the occasional occurrence of atypical strains of N. asteroides.

Aged↗
PubMed1990

DNA probes for the identification of Nocardia asteroides.

DNA probes for the rapid identification of Nocardia asteroides were obtained by constructing a genomic library of strain GUH-2 in the lambda cloning vector EMBL3. Of 50 recombinant clones tested, 2 were identified that hybridized with 31% of the N. asteroides strains in a reference collection without cross-hybridization with related members of the Actinomycetales. Additional libraries were then generated from selected strains of N. asteroides that had failed to hybridize with any of the GUH-2 clones. Four additional clones were obtained from these strains which, when pooled, provided DNA probes specific for all of the N. asteroides strains tested.

DNA Probes↗
PubMed1992

Clinical demonstration of isolation of Nocardia asteroides on buffered charcoal-yeast extract media.

Nocardia asteroides was isolated only from sputum samples, obtained from three patients with pulmonary nocardiosis, that had been cultured onto buffered charcoal-yeast extract (BCYE) and selective BCYE media as part of laboratory workups for Legionella species. A decontamination procedure with low-pH pretreatment (KCl-HCl solution) had been performed on the sputa prior to culture onto the BCYE media because direct cultures on the media were overgrown with commensal microflora. Chalky white colonies, 0.5 to 1.0 mm in diameter, that were subsequently identified as N. asteroides grew well on the BCYE media. Thus, the techniques and the selective media used for Legionella species were useful for isolating Nocardia species from sputum.

Agar↗
PubMed1994

Opacification of Middlebrook agar as an aid in distinguishing Nocardia farcinica within the Nocardia asteroides complex.

Among 58 aerobic actinomycetes isolated from different sources and geographical locations, none of 23 Nocardia asteroides isolates, at 18 N. farcinica isolates, 1 of 5 N. otitidiscaviarum isolates, and 1 of 4 Rhodococcus species isolates opacified Middlebrook 7H10 medium. Within the N. asteroides complex, this characteristic, together with growth at 45 degrees C and resistance to each of erythromycin, cefotaxime, and tobramycin, provides a simple means of distinguishing N. farcinica from N. asteroides.

Actinomycetales↗
PubMed1976

Nocardia asteroides keratitis. A case report.

An 11-year-old girl developed a corneal ulcer five days after sustaining a corneal abrasion from a fishline sinker. After more than three weeks, the epithelial defect had closed, but superficial stromal opacities in a ring-like distribution had not cleared on topical gentamicin, prednisolone 1% and atropine. Several scrapings disclosed the presence of branching hyphae on smear, eventually identified as Nocardia asteroides by culture. Although sensitivity studies suggested that subconjunctival ampicillin and hourly sodium sulphacetamide would constitute effective treatment, resolution was only partial on this regimen. Only when penicillin G drops were added did the cornea clear maximally and the epithelium heal.

Ampicillin↗
PubMed1979

Nocardia asteroides keratitis.

Nocardia asteroides has been reported as the cause of keratitis in only 7 cases and of other ocular disease in another 12 cases. We report a case of N. asteroides keratitis that presented 3 weeks after rural trauma and progressed despite trials of appropriate antibiotics. Seven weeks after the origianl injury a successful conjunctival flap was placed over the cornea. The morphology and the sensitivity testing of N. asteroides to antibiotics appears necessary before reliable information can be obtained for clinical use. Moreover, our case did not show the relatively benign course of other reported cases of nocardia keratitis.

Adolescent↗
PubMed1979

Prosthetic valve endocarditis resulting from Nocardia asteroides.

Nocardia asteroides was isolated from the prosthetic valve of a 64-year-old woman who had died of endocarditis after aortic valve replacement. Multiple blood cultures had all been negative. This organism is increasingly being recognised as a pathogen and is usually sensitive to sulphonamides. These should be tried in culture negative endocarditis unresponsive to standard therapy.

Aortic Valve↗