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PubMed1991

[Rhodococcus erythropolis infection in HIV-associated immunodeficiency].

We report the first case in the literature of human infection with Rhodococcus erythropolis in an HIV-positive patient. A 24-year-old bisexual flight attendant had severe HIV-associated immunodeficiency with a CD4 cell count of 0.02 G/l. He complained of multiple subcutaneous nodules at different sites on the extremities. Biopsy of one node at his left knee revealed granulomatous inflammation filled with acid-fast rods. These bacteria were identified as Rhodococcus erythropolis. The disseminated infection was restricted to the skin and showed a slow response to long-term therapy with amoxicillin/clavulanic acid. No relapse has been observed more than 6 months after discontinuation of antibiotic therapy. The etiology of a concomitant polyarthritis remains unknown; a relationship with the rhodococcus infection is possible as the arthritis responded well to the antibiotic therapy and did not reactivate after discontinuation of antibiotics. Due to the difficult isolation technic, this pathogen may be overlooked in routine diagnostic procedures. The implications in clinical practice are discussed.

Actinomycetales Infections↗

PubMedDate not supplied

[Emergent pathologies: Rhodococcus equi infection in the acquired immunodeficiency syndrome].

Rhodococcus equi is an intracellular facultative, gram-positive, partially acid-fast, cocco-bacillary microorganism of increasing importance as a pathogen in severely immunocompromised HIV-positive patients. Rhodococcus equi may cause invasive pulmonary infection, bacteremia and disseminated infection. Rhodococcus equi is easily cultured from blood or sputum on standard media, but is frequently regarded as a contaminant. Delay in establishing a definite diagnosis may result in a poor outcome in most cases. Treatment in humans is not standardized. Surgical intervention may be beneficial in selected cases.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

Rhodococcus equi: first case in a heart transplant recipient.

Rhodococcus equi is a gram-positive diphtheroid that occasionally affects immunocompromised patients, usually causing a chronic respiratory infection with cavitating pulmonary opacities on chest radiograph that resemble mycobacterial or fungal disease. Etiologic diagnosis presents a number of pitfalls, because Rhodococcus equi isolates mimic many of the characteristics of other microorganisms more familiar to the laboratory staff. The treatment of choice for this disease has not yet been established, and its mortality rate is greater than 50% in individuals with human immunodeficiency virus and 20% to 25% among the remaining patients. We describe here the first case of Rhodococcus equi infection in a heart transplant recipient. Clinical presentation was typical, and treatment with a sensitivity-based combination of antibiotics resulted in resolution of both the clinical and radiologic picture.

Adult↗

PubMed1993

Spheroplast formation and plasmid isolation from Rhodococcus spp.

The genus Rhodococcus comprises aerobic gram-positive actinomycetes that show considerable morphological and metabolic diversity and are known to be involved in the development of plant diseases and degradation of environmental pollutants. We describe a method for cell lysis and large plasmid DNA isolation from Rhodococcus by creating lysozyme susceptible cells by predigestion with the enzyme mutanolysin. Mutanolysin action resulted in the liberation of reducing sugars and free amino acids from the peptidoglycan layers of the cell wall. A 1-h predigestion with mutanolysin followed by a 0.5-h incubation with lysozyme resulted in spheroplast formation. Complete lysis of cells and efficient isolation of intact large plasmid DNA (108 kb) from wild-type Rhodococcus strains was confirmed.

Chromatography, High Pressure Liquid↗

PubMed1996

[Rhodococcus equi pneumonia in patients with HIV infection: report of 2 cases and review of the literature].

BACKGROUND: Pneumonia by Rhodococcus equi is infrequent and is associated with patients with important immunosuppression. To date 66 cases of pneumonia by Rhodococcus equi in patients with HIV infection have been published. The diagnosis, problems in determining diagnosis and treatment are discussed. MATERIALS AND METHODS: Two new cases of pneumonia by Rhodococus equi in C3 stage patients with HIV infection are reported. Diagnosis was achieved by study of bronchoalveolar lavage samples with the Apy-Coryne method and gas chromatography. RESULTS: The two patients presented pneumonia, one of which was necrotizing pneumonia with localization in the upper left lung and in the lower right lung, respectively. The clinical manifestations were characterized by respiratory involvement of a subacute course with pleural involvement in both cases and hemoptisis in one. Prolonged, combined antibiotic treatment was administered with good response in both cases. One patient died at one year of diagnosis from consumptive syndrome while the other remains asymptomatic. CONCLUSIONS: Infection by Rhodococcus equi should be suspected in HIV patients with slow evolution pneumonia, especially in the pneumonia is necrotizing. Combined i.v. antibiotic treatment is recommended and followed from 3 to 5 months with an association including clarithromycin.

Actinomycetales Infections↗

PubMed1990

Crude oil and hydrocarbon-degrading strains of Rhodococcus rhodochrous isolated from soil and marine environments in Kuwait.

Soil and marine samples collected from different localities in Kuwait were screened for microorganisms capable of oil degradation. Both fungi and bacteria were isolated. The fungal flora consisted of Aspergillus terreus, A. sulphureus, Mucor globosus, Fusarium sp. and Penicillum citrinum. Mucor globosus was the most active oil degrading fungus isolated. Bacterial isolates included Bacillus spp. Enterobacteriaceae, Pseudomonas spp., Nocardia spp., Streptomyces spp.,and Rhodococcus spp. Among these Rhodococcus strains were the most efficient in oil degradation and, relatively speaking, the most abundant. Bacterial and fungal isolates differed in their ability to degrade crude oil, with Rhodococcus isolates being more active that fungin in n-alkane biodegradation, particularly in the case of R. rhodochrous. In addition to medium chain n-alkanes, fungi utilized one or more of the aromatic hydrocarbons studied, while bacteria failed to do so. R. rhodochorous KUCC 8801 was shown by GLC and post-growth studies to be more efficient in oil degradation than isolates known to be active oil degraders.

Journal Article↗

PubMed1984

Ecology of Rhodococcus equi.

A selective broth enrichment technique was used to study the distribution of Rhodococcus equi in soil and grazing animals. Rhodococcus equi was isolated from 54% of soils examined and from the gut contents, rectal faeces and dung of all grazing herbivorous species examined. Rhodococcus equi was not isolated from the faeces or dung of penned animals which did not have access to grazing. The isolation rate from dung was much higher than from other samples and this was found to be due to the ability of R. equi to multiply more readily in dung. Delayed hypersensitivity tests were carried out on horses, sheep and cattle, but only horses reacted significantly. The physiological characteristics of R. equi and the nature of its distribution in the environment suggested that R. equi is a soil organism.

Actinomycetales↗

PubMed1984

Serotaxonomical analyses of strains referred to Nocardia amarae and Rhodococcus equi.

Four strains of Nocardia amarae and four strains of Rhodococcus equi (earlier designated Corynebacterium equi) were analysed by means of the comparative immunodiffusion technique for taxonomical purposes. Nineteen reference precipitation systems, representing different species of Corynebacterium, Mycobacterium, Nocardia, Rhodococcus, Streptomyces, and related taxa were employed. The N. amarae strains differed serologically from the reference strains of Nocardia and their assignment to the latter genus was therefore questioned. Furthermore, the results provided additional evidence for the view that R. equi belongs to the genus Rhodococcus and not to the genus Corynebacterium.

Corynebacterium↗

PubMed1993

Identification and Cloning of Genes Involved in Specific Desulfurization of Dibenzothiophene by Rhodococcus sp. Strain IGTS8.

The gram-positive bacterium Rhodococcus sp. strain IGTS8 is able to remove sulfur from certain aromatic compounds without breaking carbon-carbon bonds. In particular, sulfur is removed from dibenzothiophene (DBT) to give the final product, 2-hydroxybiphenyl. A genomic library of IGTS8 was constructed in the cosmid vector pLAFR5, but no desulfurization phenotype was imparted to Escherichia coli. Therefore, IGTS8 was mutagenized, and a new strain (UV1) was selected that had lost the ability to desulfurize DBT. The genomic library was transferred into UV1, and several colonies that had regained the desulfurization phenotype were isolated, though free plasmid could not be isolated. Instead, vector DNA had integrated into either the chromosome or a large resident plasmid. DNA on either side of the inserted vector sequences was cloned and used to probe the original genomic library in E. coli. This procedure identified individual cosmid clones that, when electroporated into strain UV1, restored desulfurization. When the origin of replication from a Rhodococcus plasmid was inserted, the efficiency with which these clones transformed UV1 increased 20- to 50-fold and they could be retrieved as free plasmids. Restriction mapping and subcloning indicated that the desulfurization genes reside on a 4.0-kb DNA fragment. Finally, the phenotype was transferred to Rhodococcus fascians D188-5, a species normally incapable of desulfurizing DBT. The mutant strain, UV1, and R. fascians produced 2-hydroxybiphenyl from DBT when they contained appropriate clones, indicating that the genes for the entire pathway have been isolated.

Journal Article↗

PubMed1994

Aerobic mineralization of trichloroethylene, vinyl chloride, and aromatic compounds by rhodococcus species.

Two Rhodococcus strains which were isolated from a trichloroethylene (TCE)-degrading bacterial mixture and Rhodococcus rhodochrous ATCC 21197 mineralized vinyl chloride (VC) and TCE. Greater than 99.9% of a 1-mg/liter concentration of VC was degraded by cell suspensions. [1,2-C]VC was degraded by cell suspensions, with the production of greater than 66% CO(2) and 20% C-aqueous phase products and incorporation of 10% of the C into the biomass. Cultures that utilized propane as a substrate were able to mineralize greater than 28% of [1,2-C]TCE to CO(2), with approximately 40% appearing in C-aqueous phase products and another 10% of C incorporated into the biomass. VC degradation was oxygen dependent and occurred at a pH range of 5 to 10 and temperatures of 4 to 35 degrees C. Cell suspensions degraded up to 5 mg of TCE per liter and up to 40 mg of VC per liter. Propane competitively inhibited TCE degradation. Resting cell suspensions also degraded other chlorinated aliphatic hydrocarbons, such as chloroform, 1,1-dichloroethylene, and 1,1,1-trichloroethane. The isolates degraded a mixture of aromatic and chlorinated aliphatic solvents and utilized benzene, toluene, sodium benzoate, naphthalene, biphenyl, and n-alkanes ranging in size from propane to hexadecane as carbon and energy sources. The environmental isolates appeared more catabolically versatile than R. rhodochrous ATCC 21197. The data report that environmental isolates of Rhodococcus species and R. rhodochrous ATCC 21197 have the potential to degrade TCE and VC in addition to a variety of aromatic and chlorinated aliphatic compounds either individually or in mixtures.

Journal Article↗

PubMed1995

Direct and Rapid Analysis of the Adhesion of Bacteria to Solid Surfaces: Interaction of Fluorescently Labeled Rhodococcus Strain GIN-1 (NCIMB 40340) Cells with Titanium-Rich Particles.

A fluorimetric assay which enables direct and accurate analysis of the adhesion of bacteria to solid particles was developed. The assay is based on labeling of the bacteria with fluorescamine, which reacts with primary amino groups on the cell surface to yield a yellow fluorescence that is easily detectable by both fluorescence microscopy and spectrofluorimetry. As an example, fluorescent labeling of Rhodococcus strain GIN-1 (NCIMB 40340) cells enabled the detection and quantitative determination of their adsorption to TiO(inf2) and coal fly ash particles. Exposure of the cells to 10% acetone during the labeling reaction affected neither their viability nor their ability to adhere to these particles. Only a small fraction (;sim2%) of the total cell protein was labeled by fluorescamine upon staining of intact bacterial cells, which may indicate preferential labeling of certain proteins. Specificity studies carried out with the fluorescence assay confirmed previous findings that Rhodococcus strain GIN-1 cells possess high affinities for TiO(inf2), ZnO, and coal fly ash and low affinities for other metal oxides. In principle, the newly developed fluorimetric assay may be used for determination of cell adhesion to any solid matrix by either microscopic examination or epifluorescence measurements. In the present work, the adhesion of several other microorganisms to TiO(inf2) particles was tested as well, but their ability to adhere to these particles was significantly lower than that of Rhodococcus strain GIN-1 cells.

Journal Article↗

PubMed1996

Identification of Rhodococcus equi using the polymerase chain reaction.

Two regions in the gene coding for 16S rRNA in Rhodococcus equi were selected as species-specific primer sequences for the polymerase chain reaction (PCR). PCR using these primers was tested against 10 strains of R. equi (including the type strain) and gave positive results for all but was negative for all other tested species of Rhodococcus; representatives of the most closely related genera and a number of other bacterial species. This method could therefore be used to identify this species which can infect the lungs or other organs of horses, pigs, humans and other animals.

Actinomycetales Infections↗

PubMed2005

[Necrotizing pneumonia due to Rhodococcus equi in non HIV immunocompromised host. Case report and review].

Rhodococcus equi, is a grampositive intracellular bacillus, that causes infection mainly in immunocompromised hosts. We report the case of a 52 years old woman, with a systemic lupus erythematosus and a progressive 10 months evolution with cough, dyspnea, mucous-purulent sputum, occasionally hemoptysis, intermittent fever, and weight loss of 10%. With partial response to antibiotic treatment, radiological evolution of thoracic scanners evidenced the development of multiple bilateral areas of consolidation, some of them nodular. Percutaneous thoracic biopsy showed characteristic histology and microbiological analysis yielded the identification of Rhodococcus equi in both bronchoalveolar lavage and pulmonary biopsy. She received prolonged bi-associated antibiotic treatment with good clinical and radiological response. This agent must be considered in the study of immunocompromised patients that present with a prolonged evolution of pneumonia.

Actinomycetales Infections↗

PubMed1992

Utilization of 1,3,5-trihydroxybenzene (phloroglucinol) by a soil isolate, Rhodococcus species BPG-8.

A Gram-positive bacterial strain was isolated from oil rich soil in Newfoundland and found to utilize various di- and trihydroxylated aromatic compounds as a source of carbon and energy. This bacterium exhibited rod/coccus dimorphism during its growth cycle. Chemical analysis of cell wall composition (amino acids, sugars, and fatty acids) was performed using gas chromatography-mass spectrophotometry and high pressure liquid chromatography. Comparison of both acid production and growth substrates showed complete homology with Rhodococcus erythropolis. Growth of the isolate on phloroglucinol (1,3,5 trihydroxybenzene) occurred in the pH range 5-8; with a substrate and temperature optima of 8.0 mM and 25 degrees C. The oxidation of PG was examined using whole cells as well as crude cell extracts. PG oxidation was shown to be due to an inducible enzyme system. Tentatively the isolate was identified as Rhodococcus species BPG-8 which is able to utilize phloroglucinol as the sole source of carbon and energy.

Acids↗

PubMed1993

Nocardioform arsenic resistance plasmid characterization and improved Rhodococcus cloning vectors.

A representative of a group of related Rhodococcus arsenic resistance plasmids was characterized, locating the resistance genes and regions influencing host range and controlling copy number. This information, together with identification of antibiotic resistance determinants to replace the arsenic marker was used to construct Rhodococcus-Escherichia coli positive selection shuttle plasmids which, compared with those previously constructed, had half the size, a much higher copy number, and chloramphenicol rather than arsenic as selectable marker.

Arsenic↗

PubMed2001

Metabolic engineering of indene bioconversion in Rhodococcus sp.

We have applied the methodology of metabolic engineering in the investigation of the enzymatic bioreaction network in Rhodococcus sp. that catalyzes the bioconversion of indene to (2R)-indandiol suitable for the synthesis of cis-1-amino-2-indanol, a precursor of the HIV protease inhibitor, Crixivan. A chemostat with a novel indene air delivery system was developed to facilitate the study of steady state physiology of Rhodococcus sp. 124. Prolonged cultivation of this organism in a continuous flow system led to the evolution of a mutant strain, designated KY1, with improved bioconversion properties, in particular a twofold increase in yield of (2R)-indandiol relative to 124. Induction studies with both strains indicated that KY1 lacked a toluene-inducible dioxygenase activity present in 124 and responsible for the formation of undesired byproducts. Flux analysis of indene bioconversion in KY1 performed using steady state metabolite balancing and labeling with [14C]-tracers revealed that at least 94% of the indene is oxidized by a monooxygenase to indan oxide that is subsequently hydrolyzed to trans-(1R,2R)-indandiol and cis-(1S,2R)-indandiol. This analysis identified several targets in KY1 for increasing (2R)-indandiol product yield. Most promising among them is the selective hydrolysis of indan oxide to trans-(1R,2R)-indandiol through expression of an epoxide hydrolase or modification of culture conditions.

Catalysis↗

PubMed1995

Characterization of the Rhodococcus sp. NI86/21 gene encoding alcohol: N,N'-dimethyl-4-nitrosoaniline oxidoreductase inducible by atrazine and thiocarbamate herbicides.

A protein with a mol.mass of 51,000 (ThcE) that was induced in Rhodococcus sp. NI86/21 during assimilation of thiocarbamate herbicides, atrazine, ethanol, propanol, glycerol, propionaldehyde or ethanolamine was identified by two-dimensional electrophoresis. The thcE gene was cloned and sequenced. The deduced amino acid sequence revealed ThcE as a member of group III alcohol dehydrogenases. ThcE displayed strong homology with sequenced subunit fragments of the homodecameric N,N'-dimethyl-4-nitrosoaniline-dependent alcohol oxidoreductases (MNO) of Amycolatopsis methanolica and Mycobacterium gastri. N-Terminal sequence analysis of purified MNO from Rhodococcus sp. NI86/21 confirmed the identity with ThcE. When overproduced in Escherichia coli, ThcE was insoluble and no MNO activity was detected.

Alcohol Oxidoreductases↗

PubMed1987

Actinomycetoma caused by Rhodococcus spp.

We report a case of mycetoma caused by Rhodococcus in a 62-year-old man who presented with multiple draining sinuses of the left foot. Biopsy specimen showed granulomatous reaction and microabcesses contained granules. These granules were composed by rod and coccoid Gram-positive and partially acid-fast elements. Culture grew a 'Nocardia-like organism', confirmed at the Center for Disease Control as Rhodococcus spp.

Actinomycetales Infections↗