SEARCH · PubMed Health

Results for “Nocardia”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMedDate not supplied

[Distribution of pyrimidine blocks in the DNA of Brevibacterium linens, Arthrobacter globiformis, Nocardia corallina and Nocardia rubra].

The nucleotide composition and the frequency of pyrimidine blocks were studied in DNA of the following bacteria: Brevibacterium linens (Weignamm, 1910) Breed, 1953; Arthrobacter globiformis (Conn, 1928) Conn et Dimmick, 1947; Nocardia corallina (Bergey et al., 1923) Waksman et Henrici, 1948; Nocardia rubra (Krassilnikov, 1949) Waksman et Henrici, 1948. These organisms are classed by some microbiologists as mycobacteria (the Mycobacteriaceae family) while other authors regard them as representatives of three families belonging to two orders. About 60 percent of all pyrimidines in DNA of these bacteria are found in the sequences pur-pyr-pur and pur-pyr-pyr-pur, the number of dipyrimidines being higher than the amount of monopyrimidine nucleotides. The content of dipyrimidine nucleotides in DNA of Nocardia corallina and Nocardia rubra is higher (16.8 mole %) than the content of dipyrimidine blocks in DNA of Brevibacterium linens and Arthrobacter globiformis, in which the quantity of dipyrimidines is almost the same (13.9 and 14.4 mole %). A new characteristic, the selected mean value, is suggested to evaluate differences in the distribution of pyrimidines in DNA.

Arthrobacter↗

PubMed2025

Phenotypic and genotypic profiles of clinical isolates of various Nocardia species to carbapenems and fluoroquinolones.

OBJECTIVES: To establish patterns of the antimicrobial susceptibility of Nocardia species to carbapenems and fluoroquinolones and analysis of phenotypic-genotypic correlations. METHODS: Isolates were identified to the species using 16S rRNA, secA1, or rpoB gene sequencing analysis. The antimicrobial susceptibility testing was performed using the broth microdilution method, and WGS was employed to analyse the presence of resistance genes and/or mutations of Nocardia species against carbapenems and fluoroquinolones. RESULTS: Among 143 Nocardia isolates, N. farcinica (27.27%, 39/143) and N. cyriacigeorgica (25.17%, 36/143) were the most common species, followed by N. abscessus Complex (18.88%, 27/143). The MIC90s of the seven carbapenems were 8 mg/L for doripenem, 8 mg/L for meropenem, 16 mg/L for ertapenem, 16 mg/L for biapenem, 64 mg/L for imipenem, 64 mg/L for faropenem and 128 mg/L for tebipenem, respectively. The susceptibility rates to imipenem were 76.9% and 88.9% for N. farcinica and N. cyriacigeorgica, respectively, but only 14.3% and 0% for N. otitidiscavarium and N. brasiliensis, respectively. Further, 90% of N. brasiliensis and 50% of N. otitidiscaviarum isolates were susceptible and intermediate to meropenem. WGS identified blaFAR-1 gene in N. farcinica and blaAST-1 gene in N. cyriacigeorgica, respectively. The MIC90s of the four fluoroquinolones were 1 mg/L for sitafloxacin, 4 mg/L for nemonoxacin, 4 mg/L for moxifloxacin and 16 mg/L for ciprofloxacin, respectively. The susceptibility rate of Nocardia species to ciprofloxacin was low except for N. farcinica. The resistance to fluoroquinolones arise from mutations in the gyrA gene. CONCLUSIONS: Nocardia spp. exhibited varying patterns of susceptibility to carbapenems and fluoroquinolones respectively. Importantly, different Nocardia spp. exhibited different patterns of susceptibility to carbapenems and fluoroquinolones, respectively.

Nocardia↗

PubMed1978

Beta-lactamase production and resistance to beta-lactam antibiotics in Nocardia.

Although ampicillin has been suggested as a useful agent for the treatment of nocardiosis in man, little is known regarding the presence of beta-lactamase in Nocardia or its possible role in determining resistance to ampicillin and the other beta-lactam antibiotics. We have evaluated 55 isolates of Nocardia for susceptibility to five beta-lactam antibiotics and for the presence of beta-lactamase. Nocardia were resistant to penicillin G, cloxacillin, and cefazolin, but 27 and 62% were susceptible to 3.1 and 25 mug of ampicillin per ml, respectively. Almost 90% of these ampicillin-susceptible or intermediate strains were also susceptible to carbenicillin. The combination of ampicillin and cloxacillin was synergistic against many ampicillin-resistant strains. Beta-lactamase was detected in 89% of Nocardia isolates when intact cells were used and in six of six strains after cell fractionation. This beta-lactamase was most active against penicillin G and ampicillin, with lesser activity against carbenicillin and cephaloridine. These studies suggest that beta-lactamase may be present in all clinical isolates of Nocardia and that mechanisms of antimicrobial resistance other than or in addition to beta-lactamase are responsible for resistance of Nocardia to ampicillin and carbenicillin.

Ampicillin↗

PubMed1977

In vitro response of rabbit alveolar macrophages to infection with Nocardia asteroides.

The interaction of Nocardia asteroides with cultured "normal" nonimmune rabbit alveolar macrophages was studied by light and electron microscopy. It was shown that the alveolar macrophage response to the more virulent strain (N. asteroides 14759) was quite different from the response to the less virulent organism (N. asteroides 10905). N. asteroides 14759 elicited a dramatic in vitro response of the macrophages toward the nocardial infection. Within a few hours postinfection, there was a migration of macrophages toward other cells actively infected with viable nocardia, so that at 6 h considerable macrophage aggregation on the cover slips had occurred. Many of the macrophages within these aggregates exhibited tight cell-to-cell contact, whereas others were observed to fuse, forming multinucleate giant cells, with many containing more than 10 nuclei. Upon continued incubation, these giant cells appeared to destroy the intracellular nocardia, so that, at 24 h postinfection, gram-positive, ultrastructurally intact bacteria could not be observed. At the same time, some of the macrophage aggregates that did not fuse appeared to be unable to stop the intracellular growth of nocardia. At 12 to 24 h large numbers of gram-positive, acid-fast filaments were observed growing out from within these macrophage aggregates. The macrophage response seemed dependent upon the strain of Nocardia infecting them, since N. asteroides 10905 did not induce a similar response within the macrophage population.

Animals↗

PubMed1978

Disseminated Nocardia caviae with positive blood cultures.

Disseminated Nocardia caviae infection with multiple positive blood cultures occurred in a bone marrow transplant recipient. Positive blood cultures are unusual in disseminated Nocardia infections and N caviea is an unusual species of Nocardia to cause infections in man, although its virulence in laboratory animals is similar to N asteroides. Multiple positive blood cultures in this case suggest a continuous or recurrent bacteremia rather than a transient bacteremia as previously has been thought to occur in disseminated Nocardia infections. The marked immunosuppressed state of the patient and an indwelling venous line could also have accounted for the recurrent bacteremia.

Adult↗

PubMed1979

B-lymphocyte activation with an extract of Nocardia brasiliensis.

An extract from the pathogenic actinomycete Nocardia brasiliensis was mitogenic for murine lymphocytes. This deoxyribonucleic acid-synthetic response of whole spleen cells peaked after 48 h in culture at concentrations of Nocardia extract ranging from 10 to 200 micrograms/ml. The extract appeared to be a mitogen for B lymphocytes since cultures of spleen cells from congenitally athymic nude (nu/nu) mice and of antithymocyte serum plus complement-treated spleen cells from conventional (+/+) mice responded as well as untreated spleen cells from normal +/+ mice. Furthermore, thymocytes did not respond mitogenically to the extract. Mitogenic responses were stimulated in spleen cells from H-2(a), H-2(b), H-2(d), and H-2(k) mice, including lipopolysaccharide-nonresponder C3H/HeJ mice. This Nocardia extract also stimulated polyclonal B-cell activation to the hapten trinitrophenyl, serum protein human gamma globulin, and several mammalian erythrocytes in cultures of cells from both euthymic and nude mice. Additionally, the requirement for helper T cells in the primary in vitro immune response to sheep erythrocytes could be circumvented by the addition of this Nocardia extract. These results indicate that an extract from the pathogen N. brasiliensis can nonspecifically activate murine B lymphocytes and raise the possibility that polyclonal activation of B lymphocytes may contribute to the pathogenesis of nocardiosis.

Animals↗

PubMed1977

A method for determining in-vitro drug susceptibilities of some Nocardiae and Actinomadurae: results with 17 antimicrobial agents.

A simple timesaving method for determining drug susceptibilities in vitro of isolates of Nocardia and Actinomadura is reported. An isolate is considered "susceptible" when the quantity of drug required for inhibition of growth is that concentration which might be obtained in serum by conventional therapy. Sulfonamides remain the drugs of choice for treating disease due to Nocardia species. Although doxycycline and minocycline appear to be very effective against Nocardia species, susceptibility testing may be desirable when a physician is considering substitution of an antibiotic for a sulfonamide. Susceptibility testing also may be desired before a drug is selected for treating disease due to Actinomadura madurae.

Anti-Bacterial Agents↗

PubMed1977

Studies on corynebacterial precipitinogens common to Mycobacteria, Nocardiae and rhodochrous.

Ten strains of Corynebacterium were analyzed by means of the comparative immunodiffusion technique employing reference precipitation systems from strains of Mycobacterium, Nocardia and the rhodochrous taxon. The test strains had precipitinogens in common with the reference strains. Two of the intergenerical cross-reacting precipitinogens revealed were labelled x and y. Two other precipitinogens (alpha,beta), earlier found to be common for strains of mycobacteria, nocardiae, and rhodochrous, were not demonstrated in the corynebacterial strains, thus indicating a qualitative or quantitative serological difference between Corynebacterium and the other taxa. It was furthermore shown that the corynebacterial preparations reacted with antisera against ribosomal 30S fractions from mycobacteria. Common precipitinogens in ribosomal preparations from mycobacteria, nocardiae, rhodochrous, and corynebacteria are discussed.

Antigens↗

PubMed1978

Induction of interferon synthesis in mice by fractions from Nocardia.

Three fractions of Nocardia, Nocardia water-soluble mitogen (NWSM), Nocardia water-soluble mitogen pellet (NWSMP), and the cell wall peptidoglycan, which are mitogenic for B lymphocytes, were able to induce circulating interferon in mice, NWSMP and NWSM being the most active. The peak of interferon appeared about 2 h after injection. The interferon induced by NSWMP and NWSM was acid stable and antigenically related to viral interferon, as shown by neutralization with antibodies directed against Newcastle disease virus-induced interferon.

Animals↗

PubMed1979

Interaction of Nocardia asteroides at different phases of growth with in vitro-maintained macrophages obtained from the lungs of normal and immunized rabbits.

The interactions of cells of Nocardia asteroides GUH-2 during different stages of growth with cultured macrophages obtained from the lungs of nonimmunized and immunized rabbits were studied. The nocardial cells from all stages grew intracellularly in "normal" alveolar macrophages; however, log-phase cells increased in numbers more rapidly than did stationary-phase cells. Macrophages obtained from the lungs of specifically immunized rabbits effectively inhibited the growth of stationary-phase cells but only temporarily retarded the growth of log-phase organisms. Specific antiserum added to the nocardial cells before incubation with presensitized macrophages caused enhanced phagocytosis and inactivation of the log-phase cells but had no effect on the fate of the stationary-phase nocardia. In addition, it was fo-nd that log-phase cells were phagocytized less effectively by normal macrophages than were the stationary-phase cells, and log-phase cells were more toxic to the macrophage monolayer. From these data we conclude that secondarily induced macrophages play a major role in host resistance to pulmonary nocardial infections, and antibody may be important for effective host resistance to the filamentous form of N. asteroides. Since the nocardia were able, with time, to overcome these effects, it appears that additional host factors (such as T-lymphocytes) must be involved in an effective host response to N. asteroides.

Animals↗

PubMed1979

Association of macrophage activation with antitumor effect on rat syngeneic fibrosarcoma by Nocardia rubra cell wall skeleton.

The antitumor activities of the cell wall skeleton (CWS) of Nocardia rubra were demonstrated for syngeneic fibrosarcoma (AMC-60) in ACI/N rats in regard to macrophage activation. In the 24-hr cytolytic test, activated macrophages which were fractionated from peritoneal exudate cells induced by i.p. injection of Nocardia CWS showed significant cytolytic activity for [125I]iododeoxyuridine-labeled tumor cells. Activated macrophages also strongly inhibited [3H]thymidine incorporation into the tumor cells during the 24-hr cytostatic test. When tumor cells were inoculated s.c. with activated macrophages in the Winn-type transfer assay, subsequent tumor growth was significantly inhibited. Repeated i.p. injection of the CWS seemed to enhance these antitumor activities of macrophages. The therapeutic effect of Nocardia CWS was assessed with the ascites tumor and with the solid tumor inoculated i.m. into the hind leg. In the former treatment, repeated i.p. injections completely prevented the accumulation of ascites fluid and resulted in prolongation of the survival period. The peritoneal macrophages harvested from these survivors had a strong cytolytic activity for tumor cells in the cytolytic test. In the latter treatment, repeated intratumoral injections inhibited the growth of primary tumor and prevented metastasis. Furthermore, peritoneal resident macrophages from these tumor-bearing rats treated intratumorally with the CWS were found to be cytolytic for tumor cells in the cytolytic test.

Animals↗

PubMed1978

Factors influencing susceptibility of Nocardia species to trimethoprim-sulfamethoxazole.

Demonstration of synergism between trimethoprim and sulfamethoxazole against 10 Nocardia isolates was found to be critically dependent upon the isolate, the duration of incubation, and the trimethoprim-sulfamethoxazole ratio. Inoculum effect was not significant. The trimethoprim-sulfamethoxazole ratio in the commercial, fixed-dose combination was found to contain too little trimethoprim to be optimal for Nocardia.

Drug Combinations↗

PubMed1977

Nocardia infections in congenitally athymic (nude) mice and in other inbred mouse strains.

The mortality rate and histopathological features of Nocardia asteroides and Nocardia brasiliensis infections in congenitally athymic (nude) mice of ICR and C3H/eB origins were quite different from what we found for Swiss white mice and other inbred mouse strains (namely, C57/BL/6J, New Zealand Black, BALB/c, CBA/LAC, and C3H/eB). The immunocompetent littermates of the congenitally athymic mice occupied an intermediate position between their athymic siblings and Swiss white mice in terms of their responses to both these organisms. Macrophage ingestion and destruction of N. brasiliensis, as demonstrated by electron microscopy, was found to occur. The T-lymphocyte appears to be an essential component in normal mouse resistance to infection by both N. asteroides and N. brasiliensis.

Animals↗

PubMed1977

Bilateral intraocular Nocardia asteroides infection.

A 38-year-old man with hypogammaglobulinemia and pulmonary Nocardia asteroides infection developed an intraocular Nocardia infection. The diagnosis was confirmed by examination of a specimen removed at pars plana vitrectomy. The chorioretinal infection in one eye resolved partially, with no organisms visible on histopathologic examination of the globe at autopsy. One month before the patient's death from disseminated nocardial infection, the previously uninvolved right eye developed a new metastatic nocardial chorioretinal lesion. This lesion rapidly progressed in size until the patient's death and showed on postmortem examination the presence of organisms characteristic of N asteroides.

Adult↗

PubMed1978

Endogenous intraocular Nocardia asteroides in Hodgkin's disease.

A 60-year-old man receiving antituberculous and corticosteroid therapy for a granulomatous disease of uncertain etiology was found to have a chorioretinal mass in his right eye. Fluorescein angiography showed blockage of fluorescence by the mass and late leakage. Autopsy findings were compatible with Hodgkin's disease with disseminated nocardiosis caused by Nocardia asteroides. Organisms typical of Nocardia were found in the choroid and subretinal space. The patient's history, ophthalmic examination, and fluorescein angiographic findings suggested a type of chorioretinal involvement.

Adrenal Cortex Hormones↗

PubMed1978

Virulence of Nocardia asteroides during its growth cycle.

Cells of Nocardia asteroides undergo structural and chemical changes, especially in the cell wall, during growth in brain heart infusion broth. Experiments were devised to determine whether these changes affected the virulence of Nocardia for mice. It took, on the average, 1,380 times the number of colony-forming units at the stationary phase to achieve the same mortality induced by the log-phase cells. Cells in either the lag phase or early stationary phase of growth were intermediate in the numbers of colony forming units required to kill mice. Dry-weight determinations at different stages of growth demonstrated that the log-phase organisms were approximately 10 times heavier than stationary-phase cells. Thus, on the basis of dry-weight (micrograms) values, the average colony-forming unit of log phase is approximately 130 times more virulent than in stationary-phase cultures. Therefore, the stage of growth affects greatly the virulence of N. asteroides.

Animals↗

PubMed1978

Infectious agents in immunodeficient murine models: pathogenicity of Nocardia asteroides in congenitally athymic (nude) and hereditarily asplenic (Dh/+) mice.

Congenitally athymic (Nu/Nu), hereditarily asplenic (Dh/+), and littermate control mice were given intravenous injections of homogeneous cell suspensions of the virulent Nocardia asteroides GUH-2. Kill curve, 50% lethal dose, and kidney clearance data were obtained over a period of 3 months postinfection. N. asteroides initiated both an acute infectious process and a chronic, progressive disease in these animals when given intravenously. The heterozygous (Nu/+) mice appeared to be slightly more susceptible to the acute phase of infection than their nude littermates. In contrast, nude mice were at least 50 times more susceptible to chronic nocardial infection than were the heterozygous (Nu/+) controls. Swiss Webster specific pathogen-free mice were similar to heterozygous (Nu/+) mice in their susceptibility to N. asteroides. The hereditarily asplenic (Dh/+) mice were not as susceptible to lethal infection as were nude mice. However, asplenic mice demonstrated an inability to eliminate nocardia from infected kidneys, whereas their littermate control (+/+) mice were able to mount an effective response and destroy most of the organisms within the kidneys. Similar observations were noted when nude and heterozygous (Nu/+) littermate mice were infected in the footpad. The nude mice developed a systemic infection and died within 4 weeks with little inflammation of the footpad and no macroscopic lesions. In contrast, heterozygous (Nu/+) mice developed extensive local abscesses in the foot that persisted for at least 4 weeks. There was no animal death and no evidence of dissemination. The data presented herein indicate that T cells are essential for adequate host response against infection with a virulent strain of N. asteroides.

Animals↗

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↗