Nocardiosis in the tropical northern territory of Australia, 1997-2014

Sarah L. McGuinness, Sarah E Whiting, Rob Baird, Bart J Currie, Anna P Ralph, Nicholas M Anstey, Ric N Price, Joshua S. Davis, Steven Y C Tong

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16 Citations (Scopus)

Abstract

Background: Nocardia is an opportunistic pathogen that can cause life-threatening disease. We aimed to characterise the epidemiological, microbiological and clinical features of nocardiosis in the tropical north of Australia. Methods: We conducted a retrospective cohort study of nocardiosis diagnosed between 1997 and 2014. Population-based incidences were calculated using district population data. Results: Clinically significant nocardiosis was identified in sixty-one patients. The unadjusted population-based annual incidence of nocardiosis was 2.02 (95% confidence interval [CI] 1.55-2.60) per 100,000 people and was 1.7 (95% CI 0.96-2.90) fold higher in Indigenous compared with non-Indigenous persons (p=0.027). Of 61 patients, 47 (77%) had chronic lung disease, diabetes and/or hazardous alcohol consumption; 22 (36%) were immunocompromised; and 8 (13%) had no identified comorbidities. Disease presentations included pulmonary (69%; 42/61), cutaneous (13%, 8/61) and disseminated nocardiosis (15%, 9/61). The most commonly identified species were N. asteroides and N. cyriacigeorgica (each 11%). Linezolid was the only antimicrobial to which isolates were universally susceptible; 89% (48/54), 60% (32/53) and 48% (26/54) of isolates were susceptible to trimethoprim-sulfamethoxazole, ceftriaxone and imipenem, respectively. 18 patients (30%) required intensive care unit (ICU) admission and one-year mortality was 31%. Conclusions: The incidence of nocardiosis in tropical Australia is amongst the highest reported globally. Nocardiosis occurs in both immunocompromised and immunocompetent hosts, and is associated with high rates of ICU-admission, 1-year mortality and resistance to commonly-recommended antimicrobials. Diagnosis should be considered in patients with consistent clinical features, particularly if they are Indigenous or have chronic lung disease.

Original languageEnglish
Article numberofw208
Number of pages8
JournalOpen Forum Infectious Diseases
Volume3
Issue number4
DOIs
Publication statusPublished - 6 Oct 2016
Externally publishedYes

Keywords

  • Epidemiology
  • Immunocompromised host
  • Nocardia
  • Nocardiosis
  • Treatment

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