Petroleum-Tolerant Rhizospheric Bacteria: Isolation, Characterization and Bioremediation Potential.

Petroleum is an important energy source. Due to its intensive exploration, accidents resulting in oil spills on soil are frequent, which creates consequences to ecosystems and human health. Rhizodegradation is an efficient technique that promotes the decontamination of polluted environments through the selection and use of rhizosphere microorganisms from phytoremediation plants. The aim of this study was to isolate, identify and characterize bacteria capable of degrading petroleum from the rhizosphere of Panicum aquaticum Poir., a plant that grows in petroleum contaminated soils. Three bacteria were isolated and characterized at the morphological (Gram staining), molecular (16S rRNA gene sequence analysis) and biochemical level. These bacteria were identified as new strains of Bacillus thurigiensis, Bacillus pumilus and Rhodococcus hoagii, which have been reported as potential bioremediators in the literature. All three bacteria were able to use petroleum hydrocarbons as the sole carbon source during in vitro degradation assays. Gas chromatography analysis of these assays indicated reductions of petroleum hydrocarbons between 23% and 96% within 48 h. Among the isolated bacteria, Rhodococcus hoagii presented the highest efficiency of petroleum consumption, reaching 87% of degradation after only 24 h of cultivation, which corresponds to a higher and faster degradation than previously reported, confirming the potential use of Rhodococcus hoagii for petroleum biodegradation.

Rhodococcus equi granulomatous mastitis in an immunocompetent patient.

A 37-year-old immunocompetent woman was evaluated for progressive swelling of her left breast. Magnetic resonance imaging (MRI) showed multiple hypo-intense solid lesions and could not exclude breast cancer. Tissue biopsy was suggestive of granulomatous mastitis without any evidence of malignancy. Culture of the specimen in brain heart infusion broth grew Rhodococcus equi. The patient responded well to combination therapy with ciprofloxacin and azithromycin, and the lesions regressed in follow-up MRI. To the best of our knowledge, this is the first report of R. equi granulomatous mastitis. Accurate identification of this rare pathogen is necessary to provide appropriate treatment in granulomatous mastitis.

[Bacterial pneumonia in HIV-infected patients (excluding mycobacterial infection)]. / Pneumonies bactériennes chez les personnes infectées par le VIH (hors mycobactéries).

Respiratory infections are the most common complications in HIV patients, regardless of the degree of immunosuppression. Even though antiretroviral therapy has a protective effect on the risk of bacterial pneumonia, this still remains high (including those with CD(4)>500/mm(3)). The most frequently isolated bacteria are Streptococcus pneumoniae and Haemophilus influenzae. The clinical and radiological presentations of lower respiratory tract infections in HIV patients are quite variable. The clinical presentation is more severe and the radiological presentation is more atypical if the immunosuppression is severe. The first-line antibiotic therapy is an injectable third-generation cephalosporin (ceftriaxone or cefotaxime) or co-amoxiclav. Pneumococcal vaccination (as well as influenza vaccine) is recommended. Although rare, Nocardia spp. and Rhodococcus equi seem more common among AIDS patients.

Rhodococcus equi infection in HIV-infected individuals: case reports and review of the literature.

Rhodococcus equi is a gram-positive, coryneform bacterium that causes zoonotic infection mainly in horses and foals. It sometimes affects humans presenting as cavitary pneumonia. Immunocompromised patients, including HIV-infected patients, are more susceptible to R. equi infection. We present 10 cases of R. equi infection in HIV-positive patients admitted to our institute from 1991 to June 2008. Moreover, we have reviewed 272 cases of R. equi infection in HIV-infected persons, published from 1986 through 2008. With respect to the literature data, the R. equi strains isolated in our case series showed lower sensitivity to ceftriaxone, amoxicillin/clavulanic acid, and cotrimoxazole. Prompt diagnosis, early initiation of antiretroviral treatment and combined antimicrobial treatment seem to be effective to eradicate the infection and to improve the outcome.

Neumonía por Rhodoccocus equi en paciente con infección por el VIH. A propósito de un caso / Rhodococcus equi pulmonary infection in an HIV-infected patient and radiological worsening following treatment. Case report

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