Clinical and microbiological features of nocardiosis 1997–2003

Abstract

Nocardiosis has been believed to be caused by the members of the Nocardia asteroides complex and the Nocardia brasiliensis species. However, recent advances in genotypic identification have shown that the genus exhibits considerable taxonomic complexity and the phenotypic markers used in the past for its identification can be ambiguous. The aim of this study was to assess the species distribution of Nocardia isolates and to determine whether there are differences in pathogenicity or antimicrobial susceptibility between the different species identified. Nocardia isolates obtained over a 7 year period were retrospectively reviewed. The isolates were identified genotypically, their antibiotic susceptibility was tested and the clinical data of the 27 patients were retrieved. Eight different Nocardia species were identified: Nocardia farcinica (n59), Nocardia abscessus (n56), Nocardia cyriacigeorgica (n56), Nocardia otitidiscaviarum (n52), Nocardia nova (n51), N. nova complex (n51), Nocardia carnea (n51) and Nocardia transvalensis complex (n51). All species were susceptible to co-trimoxazole but different patterns of susceptibility to other agents were observed. All patients had active comorbidities at the time of infection. A total of 19 patients were immunosuppressed, due to human immunodeficiency virus infection, chronic corticosteroid therapy, immunosupressive therapy or haematological malignancies. Six patients displayed a Charlson comorbidity index score above 4. Global mortality was 50 % while attributable mortality was 34.6 %. Patients infected with N. farcinica -the most resistant species -had the highest Charlson index score and the highest mortality rate. Accurate identification of the species and susceptibility testing of Nocardia isolates may play an important role in diagnosis and treatment.

Species Spectrum of <I>Nocardia</I> spp. Isolated from Suspected Tuberculosis Patients

“…To best of our knowledge, this is the first report of identification of N. asteroids by microbiological methods from Iran as frequently encountered species in clinical samples. During past years, several cases of nocardiosis by N. asteroids from localized to disseminated disease, have been reported from other parts of the world [14]- [16] [24]. The second most dominant species in our clinical isolates was N. cyriacigeorgica (9 isolates, 19.5%).…”

“…One isolate from bone marrow biopsy of a patient suffering from hemophilia syndrome identified as N. abscessus. Infections by N. abscessus have been reported from different regions such as Japan [33], Germany [34], Argentine [35] and Spain [16] [24]. Three isolates were identified as N. otitidiscaviarum.…”

“…Infection due to this species was previously reported from Iran based on phenotypic methods and 16S rRNA sequencing [23]. Disease due to this species has recently been reported [25] and it represents 10.2% and 18% of the Nocardia isolates in Japan and Thailand [26] and USA [27] respectively and 22% and 32.5% from two different studies from Spain [16] [24]. Together our finding from present study and several cases of nocardiosis by N. cyriacigeorgica from other parts of the world confirm major role of the latter species in the clinical settings.…”

Disseminated Nocardiosis Due to Nocardia Species.

“…Cutaneous nocardiosis presents as cutaneous(cellulitis ,abscess),lymphocutaneous (sporotrichoid nocardiosis),subcutaneous infections.Cutaneousnocardiosis also manifests as multiple erythematous nodules after traumatic injury (5,6). The illness has disseminated character in immonocompromised patients ,with vasculits,lupuserithematousis,chronic renal failure , after transplantation and steroids treatment.…”

Disseminated Nocardiosis in an Immunocompetent Individual Infected with Nocardia brasiliensis, an Opportunistic Agent

“…Diagnosis of nocardiosis can be easily missed due to the nonspecific clinical symptoms, histological findings, and the high degree of phenotypic similarity between closely related species of the genus (6). Identification problems are imminent since conventional approaches are relatively time-consuming and considerable expertise is required (7). Therefore, molecular methods with sufficient specificity, reproducibility and sensitivity should be employed (8).…”