Nocardia veterana sp. nov., isolated from human bronchial lavage

A nocardioform bacterium was isolated from the bronchoscopic lavage of a 78-year-old man with a past history of tuberculous pleurisy, who presented with bilateral upper lobe lesions at Austin and Repatriation Medical Centre, Heidelberg, Australia. The strain was aerobic, Gram-positive, produced beige substrate mycelium and scant white aerial mycelium. It showed chemotaxonomic markers which were consistent with the classification of Nocardia: i.e. meso-diaminopimelic acid, N-glycolylmuramic acid, arabinose and galactose as diagnostic sugars; phospholipids phosphatidylinositol mannosides, phosphatidylinositol, phosphatidylethanolamine and diphosphatidylglycerol; a menaquinone with a cyclic isoprene side chain, MK-8(H4cycl.); a fatty acid pattern composed of unbranched saturated and monounsaturated fatty acids with a considerable amount of tuberculostearic acid; and mycolic acids composed of 54-62 carbon atoms with three principal mycolic acids which were mono- and polyunsaturated, showing a chain length C56, C58 and C60 and accounting for over 70% of the entire pattern. The 16S rDNA sequence showed the highest similarity to the type strain of Nocardia vaccinii; the DNA-DNA similarity of the two strains was 31%. These data, together with distinct physiological traits and molecular biological analyses, as well as chemotaxonomic results, led to the conclusion that the novel isolate represents a new species within the genus Nocardia for which the name Nocardia veterana sp. nov. is proposed. The type strain is M157222T (DSM 44445T = NRRL B-24136T).

Pulmonary nocardiosis associated with idiopathic thrombocytopenic purpura

A 69-year-old woman with idiopathic thrombocytopenic purpura, who was regularly followed and treated with prednisolone and danazol, was admitted to our hospital because of shortness of breath. Chest roentgenogram showed a large amount of left-sided pleural effusion. Gram-positive branching rods, subsequently identified as Nocardia farcinica, were isolated from the fluid. Antibiotic treatment together with pleural drainage with an intercostal catheter resulted in complete remission of pyothorax. Pulmonary nocardiosis is a rare disease, but recognition of the disease in immunocompromised patients and the prompt initiation of appropriate treatments based on isolation of the pathogen can lead to a successful outcome.

Ocular nocardia infections with special emphasis on the cornea

Nocardia are aerobic, gram-positive, nonmotile and branching filamentous bacteria. Corneal infection by Nocardia is rare. Trauma is the most common predisposing factor. Isolated case reports of nocardial infection associated with contact lens wear and laser in situ keratomileusis (LASIK) have been reported. The clinical picture usually consists of superficial patchy infiltrates, which may be arranged in a wreath pattern. Presence of gram-positive, branching, beaded filaments that stain with 1% acid-fast stain (using 1% sulfuric acid, modified Kinyoun's method) in smears of corneal scrapings is suggestive of nocardial infection. Nocardia grow on commonly used media as tiny, white, dry colonies. Available knowledge and clinical experience suggest that although sulfacetamide eyedrops can be tried as the initial drug, trimethoprim-sulfamethoxazole and amikacin are effective drugs. Once therapy is initiated, the infiltrate responds promptly and resolves, forming a corneal scar with or without vascularization, and good visual recovery can be expected.

Nocardia africana sp. nov., a new pathogen isolated from patients with pulmonary infections

Eight actinomycete strains, isolated from 8 out of 400 sputum samples examined, taken from patients with pulmonary diseases at the Chest Unit of Khartoum Teaching Hospital in the Sudan, were provisionally assigned to the genus Nocardia according to morphological criteria. These isolates were studied further in order to establish their taxonomic status. They were found to have morphological and chemical properties typical of nocardiae and formed a monophyletic clade in the 16S ribosomal DNA tree together with Nocardia vaccinii. The strains showed a unique pattern of phenotypic properties that distinguished them from representatives of recognized Nocardia species, including Nocardia vaccinii. The strains were considered to merit species status and were designated Nocardia africana sp. nov. The findings of the present study are consistent with the view that pulmonary nocardiosis may occur in a substantial proportion of patients who exhibit chronic lung diseases in African countries. It is important, therefore, that clinicians in such countries consider this condition, especially when patients with respiratory infections fail to respond to antitubercular therapy.

Primary brain abscess with Nocardia otitidiscaviarum in an intravenous drug abuser

A primary brain abscess with Nocardia otitidiscaviarum in an intravenous drug abuser is reported. Nocardia brain abscess has been reported infrequently and normally only in immunocompromised patients. The lungs are the most common primary focus, but brain abscess may also occur following direct cutaneous inoculation. In this case the clinical presentation was first diagnosed as an astrocytoma. However, N. otitidiscaviarum was isolated from the lesion after emergency craniotomy. In contrast to five cases described previously the patient survived after surgical removal and antibiotic treatment with imipenem and trimethoprim-sulphamethoxazole.

Pulmonary nocardiosis in human immunodeficiency virus infection: a tuberculosis mimic

Patients with human immunodeficiency virus (HIV) infection are prone to develop pulmonary infections like nocardiosis. It is often misdiagnosed as pulmonary tuberculosis since the manifestations are similar. A twenty-seven years old male presented with fever, cough with expectoration and weight loss for two months. Chest radiograph showed opacity in the right mid zones. Sputum smears were negative for acid fast bacilli (AFB) and revealed gram positive branching filamentous organisms resembling Nocardia species. Subsequently, Nocardia was grown on sputum culture. HIV antibody was positive by ELISA test. He was treated with co-trimoxazole. If sputum is repeatedly tested negative for AFB in the setting of radiological suspicion of tuberculosis, testing for Nocardia species should be considered in the HIV-infected patients.

The Nocardia salmonicida clade, including descriptions of Nocardia cummidelens sp. nov., Nocardia fluminea sp. nov. and Nocardia soli sp. nov

Large numbers of strains selectively isolated from soil, water and deteriorating vulcanised natural rubber pipe rings were provisionally assigned to the genus Nocardia. Twenty-eight representative isolates were found to have chemical and morphological properties typical of nocardiae. These organisms formed a monophyletic clade in the 16S rDNA tree together with Nocardia salmonicida. Three of the strains, isolates S1, W30 and R89, were distinguished from one another and from representatives of the validly described species of Nocardia using genotypic and phenotypic data. These organisms were considered to merit species status and were named Nocardia cummidelens sp. nov., Nocardia fluminea sp. nov. and Nocardia soli sp. nov. respectively. Additional comparative studies are needed to resolve the finer taxonomic relationships of the remaining isolates assigned to the Nocardia salmonicida clade and to further unravel the extent of nocardial diversity in artificial and natural ecosystems.

Nocardial infection as a complication of HIV in South Africa

OBJECTIVES

To assess the occurrence, clinical and microbiological features of nocardial infections complicating HIV in Soweto, South Africa.

METHODS

A prospective study was carried out over a 2-year period. Patients were identified after isolation of Nocardia spp. from a clinical specimen. Clinical details were recorded. The nocardial isolates were identified to species level and susceptibility tests performed.

RESULTS

Ten patients were identified as having nocardial disease complicating HIV. Clinical presentations were pulmonary (five patients), pulmonary and cerebral (one patient), cerebral (one patient) and skin and soft tissue infection of the lower limb (three patients). Three infections were fatal. The isolates were Nocardia asteroides (seven patients), N. farcinica (two patients) and Nocardia spp. (one). Isolates of N. farcinica demonstrated opacification of Middlebrook agar. All isolates were sensitive to amikacin and minocycline. Most nocardial isolates were susceptible to cefotaxime, imipenem and coamoxiclav. In vitro resistance to cotrimoxazole was present in five.

CONCLUSIONS

Nocardial infection occurs as a complication of HIV infection in the Republic of South Africa. Pulmonary cases may be difficult to distinguish from tuberculosis. Nocardia asteroides is the most common species isolated. Nocardia farcinica has resistance to multiple antibacterial agents and demonstrates opacification of Middlebrook agar, a useful screening test for this species. Agents with good in vitro antinocardial activity were amikacin, minocycline, cefotaxime, imipenem and coamoxiclav. There was a high level of resistance in vitro to cotrimoxazole.

[Pulmonary Nocardia otitidiscaviarum infection in an immunocompetent host]

A rare case of pulmonary Nocardia otitidiscaviarum (N. otitidiscaviarum) was encountered in an immunocompetent host. A 74-year-old man was admitted to our hospital with a high fever and a productive cough. His chest radiograph and CT scan revealed infiltrative shadows in the right middle and lower lung fields. Although several antibiotics (third-generation cephalosporin, minocycline, imipenem) were administered, the fever and cough persisted, and C-reactive protein remained elevated. Repeated sputum cultures showed normal flora, so a transbronchial lung biopsy and bronchoalveolar lavage (BAL) were performed bronchoscopically at the right S5. The BAL fluid contained acid-fast, branching filamentous structures. The microorganism was identified as N. otitidiscaviarum by the Research Center for Pathogenic Fungi and Microbial Toxicoses (Chiba University). Trimethoprim-sulfamethoxazole was therefore administered, but the fever continued to rise daily, and C-reactive protein remained elevated. This isolated N. otitidiscaviarum showed resistance to multiple antimicrobial agents in vitro when examined by the disk diffusion method, and so, on the basis of the antibiogram, the patient was treated with clarithromycin (oral, 600 mg/day) plus amikacin (400 mg/day), which proved successful. Testing for pulmonary nocardiosis should be added to the differential diagnosis procedures for refractory pneumonia as an opportunistic infection and for community-acquired pneumonia.

Nocardia infection in heart-lung transplant recipients at Alfred Hospital, Melbourne, Australia, 1989-1998

Nocardia infections are uncommon in recipients of heart, lung, or heart-lung transplants, but such infections are well described. Frequent episodes of rejection, high-dose prednisolone treatment, renal impairment, and prolonged respiratory support have all been shown to increase the risk of Nocardia infection in this group. In this retrospective review of 540 recipients of heart, lung, or heart-lung transplants, 10 patients developed Nocardia infection (frequency, 1.85%). Infection occurred at a mean +/- standard deviation of 13+/-14.5 months after transplantation. All patients had pulmonary disease with no evidence of extrapulmonary disease. The Nocardia infection did not contribute directly to patient deaths. Coinfection with other pathogens was present in 6 patients, and 2 patients had sequential infections. Radiological findings varied. All isolates were susceptible to trimethoprim-sulfamethoxazole, amikacin, and imipenem. Treatment regimens varied. Two (30%) of 6 patients treated with trimethoprim-sulfamethoxazole developed adverse reactions, which necessitated a change in antibiotic therapy. The optimal treatment regimen, which comprises both the antimicrobial agent and the length of treatment, is unclear.

Subretinal abscess due to Nocardia farcinica infection

PURPOSE

Nocardia infection of the eye is uncommon. A case of choroidal abscess due to Nocardia farcinica infection is presented, and the literature is reviewed.

METHODS

A 41-year-old immunocompromised man with chronic myeloid leukemia developed a unilateral choroidal abscess. N. farcinica was isolated from a simultaneous subcutaneous abscess and both infections responded to systemic sulfonamide therapy.

RESULTS

Three weeks after discontinuation of the sulfonamides, the choroidal abscess recurred with involvement of the vitreous. The infection was brought under control after reinstitution of the same drug.

CONCLUSIONS

Nocardiosis is a multisystem disease that has high mortality and ocular morbidity rates. The eyes of immunocompromised patients should be examined frequently as early detection and administration of the proper antibiotics may reduce the risk of this life-threatening infection.

[Pneumonia from Nocardia nova in lung cancer]

The clinical and radiographic manifestations of pulmonary nocardiosis are nonspecific. The diagnosis depends of the clinical suspicion for alerting the microbiology laboratory to use special culture and identification methods to initiate the appropriate therapy early. A nocardia pneumonia in a locally advanced non small cell lung cancer patients is present. Even after initiate the treatment the patient died. It is important to suspect the diagnosis of uncommon infection to begin the therapy.

[Localized nocardiosis]

Primary cutaneous nocardiosis is a rare disease. It is observed in people in contact with soil, after trauma. It is produced by an aerobic actinomyces which is found on the ground. We present a case of localized Nocardiosis placed on the left anatomical snuffbox. The patient was a 52 year old farmer. At the time of first consultation, the three year old lesions appeared as plaques which showed crusts and numerous suppurative fistulae, together with non painful nodules. He had no regional adenopathies. Material was taken for mycological direct and culture exams. A biopsy was taken for Anatomopathology. The patient remembered having suffered a trauma on the left hand by his tools in harvest time.

Head actinomycetoma with a double aetiology, caused by Nocardia brasiliensis and N. asteroides

We describe a 64-year-old man with an actinomycetoma of the frontal region of the head caused simultaneously by two aetiological agents, Nocardia brasiliensis and N. asteroides. This case is presented due to the unusual body site affected and, above all, because two aetiological agents were isolated.

Humoral response in a patient with cutaneous nocardiosis

The clinical appearance of infection due to Nocardia spp. varies widely. The low sensitivity of direct microscopy and the slow growth of the organism challenge the laboratory diagnosis. We present the case of a skin abscess in an immunocompetent man caused by Nocardia brasiliensis. Diagnosis was made by cultivation and 16S rRNA sequencing. Using indirect immunofluorescence and Western blot, a strong antibody response to the N. brasiliensis isolate could be demonstrated. Serological tests might therefore be useful for the diagnosis and management of nocardial infections.

Unilateral vocal cord paralysis as a result of a Nocardia farcinica laryngeal abscess

Nocardia farcinica is an emerging pathogen in immunocompromised hosts, accounting for 20% of Nocardia isolates in the USA and 13-44% of isolates in Europe. The case of a 72-year-old lymphoma patient with a laryngeal abscess caused by Nocardia farcinica is presented. The initial clinical manifestation was unilateral vocal cord paralysis, which improved following surgical drainage of the abscess and therapy with imipenem. The English-language literature on human Nocardia farcinica infection is reviewed.

Infection caused by Nocardia farcinica: case report and review

Nocardia farcinica is a rare Nocardia species causing localised and disseminated infections. A case of Nocardia farcinica infection is presented, and 52 cases previously reported in the literature are reviewed. The hosts usually had predisposing conditions (85%), and acquired the infection through the respiratory tract or skin; the infection then often spread to the brain, kidney, joints, bones and eyes. Pulmonary or pleural infections (43%), brain abscesses (30%) and wound infections (15%) which failed to respond to conventional antimicrobial therapy were the more frequent forms of infection. Nocardia farcinica was frequently isolated from pus (100% of samples), bronchial secretions (41%) and biopsy specimens (63%), but isolation from blood and urine, as in the case presented here, is rare. Antibiotic therapy was adequate in 61% of the patients in whom it was specified, the agents most frequently given being trimethoprim-sulfamethoxazole (54%), amikacin combined with imipenem (7%) and amoxicillin-clavulanate (7%). The high mortality (31%) can be attributed to the severe underlying diseases present, difficulties encountered in identifying the pathogen, inappropriate therapy and late initiation of therapy. Although an infrequent pathogen, Nocardia farcinica should be kept in mind as a cause of infection especially in immunosuppressed patients with indolent infections not responding to third-generation cephalosporins.