title: Nocardiosis in the Tropical Northern Territory of Australia, 1997-2014.
abstract: BACKGROUND
  Nocardiais an opportunistic pathogen that can cause life-threatening disease. We aimed to characterize 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 61 patients. The unadjusted population-based annual incidence of nocardiosis was 2.02 (95% confidence interval [CI], 1.55-2.60) per 100000 people and was 1.7 (95% CI, .96-2.90) fold higher in Indigenous compared with non-Indigenous persons (P= .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 of 61), cutaneous (13%; 8 of 61), and disseminated nocardiosis (15%; 9 of 61). The most commonly identified species wereNocardia asteroidesandNocardia cyriacigeorgica(each 11%). Linezolid was the only antimicrobial to which isolates were universally susceptible; 89% (48 of 54), 60% (32 of 53), and 48% (26 of 54) of isolates were susceptible to trimethoprim-sulfamethoxazole, ceftriaxone, and imipenem, respectively. Eighteen patients (30%) required intensive care unit (ICU) admission, and 1-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 it 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.
authors.affiliation: Department of Infectious Diseases and.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: McGuinness
authors.affiliation: Department of Infectious Diseases and.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Whiting
authors.affiliation: Department of Infectious Diseases and; Territory Pathology, Royal Darwin Hospital, Darwin, Australia.
authors.forename: Rob
authors.initials: R
authors.lastname: Baird
authors.affiliation: Department of Infectious Diseases and; Global and Tropical Health, Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Currie
authors.affiliation: Department of Infectious Diseases and; Global and Tropical Health, Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Anna P
authors.initials: AP
authors.lastname: Ralph
authors.affiliation: Department of Infectious Diseases and; Global and Tropical Health, Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Anstey
authors.affiliation: Department of Infectious Diseases and; Global and Tropical Health, Menzies School of Health Research, Charles Darwin University, Darwin, Australia;; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.
authors.forename: Ric N
authors.initials: RN
authors.lastname: Price
authors.affiliation: Global and Tropical Health, Menzies School of Health Research, Charles Darwin University, Darwin, Australia;; Department of Infectious Diseases, John Hunter Hospital, Newcastle, Australia.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Davis
authors.affiliation: Department of Infectious Diseases and; Global and Tropical Health, Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Steven Y C
authors.initials: SY
authors.lastname: Tong
keywords: Nocardia; epidemiology; immunocompromised host; nocardiosis; treatment.