Nocardia veterana isolated from ascitic fluid of a patient with human immunodeficiency virus infection

Nocardia veterana infections: case report and systematic review

Members of the genus Nocardia are filamentous, Gram-positive, aerobic bacteria and exist ubiquitously in most environments. In 2001, the species Nocardia veterana was first isolated, and it predominantly causes pulmonary infections in immunocompromised hosts. We present the first report of a soft-tissue abscess caused by N. veterana in a 59-year-old woman being treated for chronic cutaneous graft-versus-host disease. After failing to improve with empirical treatment, two incision and drainage procedures were required. She subsequently completed a 1-year course of oral antibiotic therapy consisting of trimethoprim-sulfamethoxazole then azithromycin. No relapse occurred over the next 5 years of follow up. To better characterize N. veterana infections, we performed a systematic literature review and summarized all previously reported cases. Overall, the rising prevalence of immunocompromising conditions warrants increased vigilance for infections caused by atypical or opportunistic pathogens.

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Systematic review of Nocardia veterana infections.

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First report of N. veterana soft tissue abscess.

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N. veterana typically causes pulmonary infections in immunocompromised hosts.

The emergence of rare nocardiosis following allogeneic hematopoietic stem cell transplantation in the era of molecular taxonomy

OBJECTIVE

The purpose of this study was to describe the clinical features of nocardiosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT), focusing on new Nocardia species.

METHODS

We retrospectively reviewed data from patients with nocardiosis after allo-HSCT treated at our hospital and documented cases in the medical literature.

RESULTS

Fifty-seven cases were identified from our institution and the literature review. Although 51 patients (89.5%) responded to initial treatment, 28 (49.1%) patients were switched over to other treatment regimens due to the recurrence of nocardiosis or adverse events of antimicrobials. Nocardiosis-attributed mortality occurred in ten patients (17.5%). Antimicrobial susceptibilities varied among intra- and inter-species except linezolid (LZD). In the present study, five species were newly discovered after 2000, including N. cyriacigeorgica, N. veterana, N. abscessus, N. aobensis, and N. mexicana. All isolates of N. cyriacigeorgica, N. veterana, N. abscessus, and N. aobensis were sensitive to trimethoprim/sulfamethoxazole, amikacin (AMK), imipenem (IPM), and LZD; however, N. mexicana was resistant to AMK and IPM.

CONCLUSION

Newly identified Nocardia species have various antimicrobial susceptibility patterns. Long-term maintenance therapy could be challenging due to the adverse events of antimicrobials, especially in the allo-HSCT setting. Prudent evaluation is crucial for selecting a second-line or further treatment options.

Nocardia veterana: disseminated infection with urinary tract infection

Nocardia spp. are a group of aerobic actinomycetes widely distributed in soil, and associated with severe opportunistic infections, essentially pulmonary infections. We report the first case of disseminated infection associated with urinary tract infection caused by Nocardia veterana. The diagnosis was difficult; despite the presence of pulmonary nodules, the lung biopsies remained negative while only one aerobic blood culture and the urine culture were positive for N. veterana, identified after a 16S rDNA gene sequence analysis. Few cases of clinical importance due to N. veterana have been published since its characterization. The bacteriological diagnosis of nocardiosis can be difficult to establish because of the delayed growth and the specific techniques that are required. This case illustrates the necessity of performing specific investigations in immunocompromised patients who present with infectious disease because the severity of this infection requires early diagnosis and quick initiation of appropriate antibiotic therapy.

First case report of Nocardia veterana causing nodular lymphangitis in an immunocompromised host

We report a unique case of ascending cutaneous lymphangitis in a 72-year-old immunocompromised man from which a newly described Nocardia species was isolated by 16S ribosomal gene sequencing. Treatment with trimethoprim-sulfamethoxazole resulted in successful resolution of symptoms. To the best of our knowledge, this is the first case report of N. veterana implicated in causing ascending cutaneous lymphangitis.

First report of a brain abscess caused by Nocardia veterana

Among Nocardia species causing infections, Nocardia veterana is rarely isolated and is mostly described as causing pulmonary infections. This is the first presentation of a case of brain abscess attributable to an N. veterana infection in a patient with type 2 diabetes. Prolonged antibiotic therapy with trimethoprim-sulfamethoxazole led to successful clinical recovery.

Bacteremia caused by an undescribed species of Janibacter

A yellow-pigmented rod- to coccoid-shaped coryneform microorganism was isolated from the blood of a patient with acute myeloid leukemia. It was identified by 16S rRNA gene sequencing as a previously undescribed species of Janibacter. The isolate was susceptible to penicillins, aminoglycosides, fluoroquinolones, and glycopeptides.

Presence of bacterial phage-like DNA sequences in commercial Taq DNA polymerase reagents

Many studies have reported the presence of bacterial DNA contamination in commercial Taq DNA polymerase reagents. This is the first report of the presence of phage-like DNA sequences in certain commercial Taq DNA polymerase reagents. Precautions are needed when using amplification reagents with exogenous DNAs.

Identification and biodegradation potential of tropical aerobic hydrocarbon-degrading microorganisms

Screening of aerobic culturable hydrocarbon (HC)-degrading microorganisms isolated from petroleum-polluted soils and cyanobacterial mats from Indonesia resulted in the collection of 33 distinct species. Eight bacteria, 21 fungi and 4 yeasts were identified to the specific level by molecular and phenotypic techniques. Bacterial strains belonged to the genera Gordonia, Brevibacterium, Aeromicrobium, Dietzia, Burkholderia and Mycobacterium. Four species are new and not yet described. Fungi belonged to Aspergillus, Penicillium, Fusarium, Amorphoteca, Neosartorya, Paecilomyces, Talaromyces and Graphium. Yeasts were Candida, Yarrowia and Pichia. All strains were cultivated axenically in synthetic liquid media with crude oil as sole carbon and energy source. After incubation, the detailed chemical composition of the residual oil was studied by gravimetric and gas-chromatographic techniques. Thirteen parameters for assessing the biodegradation potential were defined and computed for each strain. Maximum degradation was observed on the saturated HCs (n- and isoalkanes, isoprenoids), whereas aromatic HC degradation was lower and was related to the structural composition of the molecules. A principal components analysis (PCA) permitted grouping and classifying the strains as a function of their degradative capacities. It was shown that the most active strains produced polar metabolites which accumulated in the resins and asphaltene fractions. These fractions are highly resistant to microbial metabolism. No taxonomic trend could be defined between microbial phyla in terms of HC biodegradation activity.