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PubMed2003

Phylogeny of the genus Nocardia based on reassessed 16S rRNA gene sequences reveals underspeciation and division of strains classified as Nocardia asteroides into three established species and two unnamed taxons.

Conventional identification of Nocardia in the routine laboratory remains problematic due to a paucity of reliable phenotypic tests and due to the yet-unresolved taxonomy of strains classified as belonging to the species Nocardia asteroides, which comprises the type strain and isolates with drug pattern types II and VI. The 16S rRNA gene of 74 representative strains of the genus Nocardia, encompassing 25 established species, was sequenced in order to provide a molecular basis for accurate species identification and with the aim of reassessing the phylogeny of taxons assigned to the species N. asteroides. The result of this phylogenetic analysis confirms that the interspecies heterogeneity of closely related nocardial species can be considerably low (a sequence divergence of only 0.5% was found between N. paucivorans and N. brevicatena). We observed a sequence microheterogeneity (sequence divergence of fewer than five bases) in 8 of 11 species of which more than one strain in the species was studied. At least 10 taxons were found that merit description as new species. Strains previously classified as N. asteroides fell into five distinct phylogenetic groups: the type strain cluster (N. asteroides sensu strictu), N. abscessus, N. cyriacigeorgica, and two clusters closely related to N. carnea or N. flavorosea. The strains within the latter two groups probably represent new species, pending further genetic and phenotypic evaluation. Restricted phenotypic data revealed that N. abscessus, N. cyriacigeorgica, and the two Nocardia species taxons are equivalent to drug patterns I, VI, and II, respectively. In the future, these data will help in finding species-specific markers after adoption of a more precise nomenclature for isolates closely related to N. asteroides and unravel confusing phenotypic data obtained in the past for unresolved groups of strains that definitely belong to separate taxons from a phylogenetic point of view.

DNA, Bacterial↗
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↗
PubMedDate not supplied

[Comparative electron microscopic study of cultures of Nocardia asteroides and of the Nocardia-like variant, Actinomyces chrysomallus].

The ultrastructural organization of the red-orange cultures of Nocardia (Proactinomyces) asteroides was compared with that of a Nocardia-like variant of Actinomyces (Streptomyces) chrysomallus isolated upon the inoculation of the submerged parent culture. The comparison has demonstrated for the first time that the major difference consists in the structure of their cross partitions. In Nocardia, the septa is split at all stages of its formation; in the Nocardia-like variant, the partitions have the same structure as the cultures of the genus Actinomyces (Streptomyces). Therefore, the accepted terminology is conventional.

Culture Media↗
PubMed1976

Nocardia asteroides and Nocardia brasiliensis infections in mice.

A model for Nocardia asteroides and Nocardia brasiliensis infections in Swiss white mice has been established without the addition to the inocula of any form of adjuvant. Serial histopathological studies revealed that these two actinomycetes cause lesions that are quite different in their features. An acute suppurative abscess characterizes the lesions of N. asteroides. In the case of N. brasiliensis infections a granuloma is produced in which a striking feature is the presence of large numbers of foam-laden macrophages, although occasional exceptions to this pattern were noted. Electron microscopic studies demonstrated that these macrophages contain within their cytoplasm organisms in varying stages of degeneration. Repeated mortality studies in mice failed to demonstrate differences in mortality rates produced by N. asteroides and N. brasiliensis. Thus, despite relatively trivial biochemical and antigenic differences between these two species of Nocardia, the local pathogenic response is quite different. The presence in the "brasiliensis lesion" of foamy macrophages with intracellular organisms is reminiscent of the histopathological features of lepromatous leprosy and of disseminated Myocobacterium bovis infection when this occurs in the immune suppressed situation. It is possible that N. brasiliensis infection produces a depression of cellular immunity that modifies the local host response to the organism.

Animals↗
PubMed1980

Resistance to Nocardia brasiliensis infection in mice immunized with either Nocardia or BCG.

Different vaccination procedures to increase the mechanisms of host resistance to Nocardia brasiliensis were studied in mice. When mice were challenged in the footpad, 2 x 10(8) N. brasiliensis 20 days after footpad inoculation with either viable or killed N. brasiliensis, the mice demonstrated significant resistance to infection when compared with noninfected and nonimmunized mice. The degree of resistance seems to be correlated with the delayed-type hypersensitivity response in the vaccinated animals. Vaccination with another acid-fast bacilli, BCG, afforded both a mild protection and low DTH reactivity. Antibody levels to Nocardia were similar in either Nocardia- or BCG-treated groups indicating that they do not play an important role in resistance to infection by N. brasiliensis.

Animals↗
PubMed1980

An ultrastructural comparison of the cell envelopes of selected strains of Nocardia asteroides and Nocardia brasiliensis.

Growth curves were determined for three strains each of Nocardia asteroides and Nocardia brasiliensis. Two strains of N. brasiliensis and one strain of N. asteroides had longer lag periods of growth than the remaining three strains. All strains had generation times of approximately 5.5 hours. The ultrastructure of the cell envelope of each Nocardia strain in early stationary phase growth was also examined. All the strains had typical trilaminar cell walls and cell membranes. The thickness of the cell wall layers, especially the inner peptidoglycan layer, varied from strain to strain. The inner layer of two strains of N. brasiliensis and one strain of N. asteroides was 12 nm or more in thickness, while that of the remaining three strains was 7 nm thick. These observed differences in growth patterns and/or thickness of the cell wall layers could be correlated to the varying degrees of virulence as well as the divergent pathologies exhibited by these organisms.

Cell Wall↗
PubMed1964

RECOMBINATION BETWEEN NOCARDIA ERYTHROPOLIS AND NOCARDIA CANICRURIA.

Adams, James N. (University of South Dakota, Vermillion). Recombination between Nocardia erythropolis and Nocardia canicruria. J. Bacteriol. 88:865-876. 1964.-Nutritionally complementary auxotrophic mutants derived from Nocardia erythropolis did not yield prototrophic recombinants when progeny from mixed cultures or newly mixed strains were inoculated onto minimal medium. Similarly, complementary auxotrophic mutants of N. canicruria did not produce prototrophic recombinants. When interspecific mating was attempted between complementary mutants of N. erythropolis and N. canicruria, prototrophic recombinants were recovered at frequencies dependent, in part, upon the auxotrophic strains used in the test crosses. Growth of the parental types in mixed cultures was necessary for the production of recombinant progeny. Direct selection for recombinants by inoculating the selective medium with a mixture of parental types without prior mixed growth did not result in the recovery of recombinants. Varying the medium upon which mixed growth occurred, or varying the ratio of N. erythropolis to N. canicruria cells used as inocula, did not greatly affect the recovery of recombinants. Heat-killing one or the other of the parental types prevented recombinant production. The lack of recovery of recombinants from crosses of homologously derived strains suggested that a mating factor controls recombination. The mating factor was not eliminated by acriflavine treatment. The recovery of a recombinant strain capable of forming recombinants with either N. erythropolis or N. canicruria, and the recovery of another strain which mated only with N. erythropolis in backcrosses, suggests that the mating factor may be of a multiple nature.

Adenine↗
PubMed1995

New Nocardia taxon among isolates of Nocardia brasiliensis associated with invasive disease.

Nocardia brasiliensis, the second most frequently isolated aerobic actinomycete in the clinical laboratory, is usually associated with localized cutaneous infections. However, 22% of 238 N. brasiliensis isolates from the United States and 12% of 66 isolates from Queensland, Australia, which had been collected over a 17-year period, were associated with extracutaneous and/or disseminated diseases. Of the 62 invasive isolates, 37 (60%) were susceptible to ciprofloxacin and/or were susceptible to clarithromycin and resistant to minocycline, compared with only 6 (3%) of 242 localized cutaneous isolates. The 43 isolates with this susceptibility pattern appeared to define a new taxon. They were similar to Nocardia asteroides complex isolates clinically in proportions from persons with pulmonary (70%), central nervous system (23%), and/or disseminated diseases (37%) in the setting of corticosteroids (74%) or AIDS (14%). This putative new taxon differed from N. brasiliensis in the hydrolysis of adenine (92 versus 4%), beta-lactamase patterns on isoelectric focusing, and the presence of two early mycolic acid-ester peaks by high-performance liquid chromatography. Restriction analysis of a 439-bp fragment of the 65-kDa heat shock protein gene revealed that N. brasiliensis and the new taxon had different restriction patterns with 8 of the 11 enzymes tested. Screening of invasive isolates of N. brasiliensis for susceptibility to ciprofloxacin will identify most isolates of the new taxon, which likely represents a new Nocardia species.

Base Sequence↗
PubMed1997

Molecular study of persistence of Nocardia asteroides and Nocardia otitidiscaviarum strains in patients with long-term nocardiosis.

Three Nocardia asteroides and five Nocardia otitidiscaviarum isolates recovered from three patients with long-term nocardiosis were compared by random amplification of polymorphic DNA fingerprinting, antibiotic susceptibility testing, and enzymatic characterization. Results obtained with primer DKU49 (P. Palittapongarnpim, S. Chomyc, A. Fanning, and D. Kunimoto, J. Infect. Dis. 167:975-978, 1993) provide evidence that patient A was infected by two N. asteroides strains during a single episode of nocardiosis and that patients B and C remained infected by the same strain, respectively. Resistance to minocycline that was present in the first isolate recovered from patient B reverted to intermediate resistance in the second isolate and reverted to susceptibility in the third isolate. Resistance to penicillin G and beta-lactams was acquired by the second isolate obtained from patient C.

DNA Fingerprinting↗
PubMed1988

Acid phosphatase activity in Nocardia brasiliensis and Nocardia asteroides.

Nocardia asteroides and N. brasiliensis strains were found to possess acid phosphatase activity. This enzyme was found to be cell-associated and its activity paralleled the cell mass increase seen during the Nocardia growth cycle. Of the strains tested, N. brasiliensis exhibited the highest enzymatic activity. Implications of these findings are related to current evidence which indicates that other microbial acid phosphatases may constitute potential pathogenic factors for humans.

Acid Phosphatase↗
PubMed1976

Presence and subcellular localization of two distinct mitogenic fractions in the cells of Nocardia rubra and Nocardia opaca: preparation of soluble mitogenic peptidoglycan fractions.

Fractionation of cells of Nocardia rubra and Nocardia opaca led to the separation of the cell wall and a "cytoplasmic" fraction. Both fractions were mitogenic for the splenocytes of AKR and nude mice and of rabbits. The peptidoglycan was the active part of the cell wall fraction. The products solubilized by the action of Streptomyces albus G peptidases on the peptidoglycan of N. rubra were mitogenic, but the products solubilized by lysoyme were not. Tentative structures are proposed for these fractions. The most active part of the cytoplasmic fractions could be sedimented by centrifugation and seemed to be related to the cytoplasmic membrane.

Animals↗
PubMed1999

Distribution of a Nocardia brasiliensis catalase gene fragment in members of the genera Nocardia, Gordona, and Rhodococcus.

An immunodominant protein from Nocardia brasiliensis, P61, was subjected to amino-terminal and internal sequence analysis. Three sequences of 22, 17, and 38 residues, respectively, were obtained and compared with the protein database from GenBank by using the BLAST system. The sequences showed homology to some eukaryotic catalases and to a bromoperoxidase-catalase from Streptomyces violaceus. Its identity as a catalase was confirmed by analysis of its enzymatic activity on H2O2 and by a double-staining method on a nondenaturing polyacrylamide gel with 3,3'-diaminobenzidine and ferricyanide; the result showed only catalase activity, but no peroxidase. By using one of the internal amino acid sequences and a consensus catalase motif (VGNNTP), we were able to design a PCR assay that generated a 500-bp PCR product. The amplicon was analyzed, and the nucleotide sequence was compared to the GenBank database with the observation of high homology to other bacterial and eukaryotic catalases. A PCR assay based on this target sequence was performed with primers NB10 and NB11 to confirm the presence of the NB10-NB11 gene fragment in several N. brasiliensis strains isolated from mycetoma. The same assay was used to determine whether there were homologous sequences in several type strains from the genera Nocardia, Rhodococcus, Gordona, and Streptomyces. All of the N. brasiliensis strains presented a positive result but only some of the actinomycetes species tested were positive in the PCR assay. In order to confirm these findings, genomic DNA was subjected to Southern blot analysis. A 1.7-kbp band was observed in the N. brasiliensis strains, and bands of different molecular weight were observed in cross-reacting actinomycetes. Sequence analysis of the amplicons of selected actinomycetes showed high homology in this catalase fragment, thus demonstrating that this protein is highly conserved in this group of bacteria.

Actinomycetales↗
PubMed1990

Cefotaxime-resistant Nocardia asteroides strains are isolates of the controversial species Nocardia farcinica.

A recent study of Nocardia asteroides revealed that 95% of clinical strains had one of five antibiotic resistance patterns. We found the pattern of resistance to cefotaxime and cefamandole in 19% of 200 clinical N. asteroides isolates. Isolates with this drug resistance pattern were from numerous geographic sources and were associated with significant clinical disease (56% of patients had disseminated infections). Phenotypic studies revealed that these isolates were relatively homogeneous and matched previous descriptions and reference strains of the controversial species N. farcinica. Growth at 45 degrees C, acid production from rhamnose, ability to utilize acetamide as a nitrogen and carbon source, and resistance to tobramycin and cefamandole were features of N. farcinica that could be tested in the clinical laboratory and allowed their distinction from N. asteroides. The serious nature of disease due to N. farcinica and its resistance to the newer cephalosporins suggest a clinical need for laboratory identification of this species. (Current tests used in clinical laboratories do not distinguish N. farcinica from N. asteroides.) This is the first recognition that N. farcinica has a specific drug resistance pattern and confirms the previously described concept that drug resistance patterns of N. asteroides may be associated with specific taxonomic groups.

Cefotaxime↗
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↗
PubMed1986

[Nocardia brain abscess and ventriculitis--resistance of Nocardia to sulfonamides and susceptibility to beta-lactams].

A 31-year-old man had been healthy until the end of August, 1984 when he developed a sore throat, rhinorrhea, and high fever (39 degrees C). He was found to have hematuria and leukocytosis, though his complaints were not severe, and was not absent from his work. From the September 30, he experienced continuous pains on both temple regions and the neck. On October 6, he visited our hospital without any inflammatory signs. A screening CT scan demonstrated a ring-like enhancing mass with remarkable perifocal edema in the right temporal lobe. On emergency admission on October 9, a low grade fever (37.4 degrees C) and slight leukocytosis were noted, but not other primary lesions were present. He had normal immunological function of both humoral and cellular types. A provisional diagnosis of malignant brain tumor was made, but a possibility of brain abscess was not completely ruled out. He was initially treated with antidiuretics and steroid with prophylactic antibiotics, and underwent follow-up CT scanning. After a 10-day period with no obvious changes in CT scan, he suddenly complained of severe headache and fever, and became stuporous. A subsequent CT scan showed signs of ventriculitis, and contrast-enhancing multiloculated capsules. A lumber puncture revealed an increased number of cells, and concentration of protein in the CSF. An emergency trephination and drainage of an abscess was performed. Gram positive, acid fast, and branching fungi were found in both the smear of pus, and the samples from surrounding brain tissues. These were later identified as Nocardia asteroides in bacteriological studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Composition and toxicity of diethyl ether soluble lipids from Nocardia asteroides GUH-2 and Nocardia asteroides 10905.

Virulent Nocardia asteroides GUH-2 and avirulent N. asteroides 10905 contained 8.2% and 10.6% of diethyl ether soluble lipids (DESL) per dry cell mass, respectively. Intraperitoneal (i.p.) inoculation of 250 micrograms of DESL from GUH-2 dissolved in mineral oil was toxic to mice, resulting in weight loss and death of 100% of the animals (20/20) within 20 days. In contrast, DESL from 10905 had very little toxicity, and only one mouse (1/10) died within 30 days. Three fractions resulted from DESL by silicic acid column chromatography: (1) neutral lipids and fatty acids (NFA); (2) glycolipids (GL); and (3) phospholipids (PL). Each fraction dissolved in mineral oil was inoculated into mice as described above. The NFA and PL were not toxic. GL from 10905 had low toxicity (30% of the animals died, 3/10) whereas GL from GUH-2 expressed high toxicity (100% of the animals became cachetic and died, 10/10). GL from 10905 represented a minor component (0.6% of dry cell weight) whereas GL from GUH-2 was more prominent (1.5% of dry cell wt.). Approximately 95% of GL from GUH-2 had properties of an authentic trehalose-6,6'-dimycolate standard. Infrared spectrum of the major glycolipid (GUH-2 GL) had characteristic absorptions in the fingerprint region between 800 cm-1 and 1500 cm-1. Upon alkaline hydrolysis GUH-2 GL released 76% mycolic acids in the C50 size range plus 24% trehalose.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗