title: "Multidrug-resistant tuberculosis" may be nontuberculous mycobacteria.
abstract: BACKGROUND
  Multidrug resistant tuberculosis (MDR-TB) presents a great challenge to public health, especially for developing countries. Some nontuberculous mycobacteria (NTM) cause the similar clinical and radiological characteristics with tuberculosis. We aimed to identify the frequency of NTM infections among subjects who were suspected to have MDR-TB due to lack of response to anti-TB treatment.
  
  
  METHODS
  This retrospective study evaluated patients with suspected MDR-TB due to lack of sputum conversion after 2-3 month therapy with first line anti-TB treatment from 2009 through 2014. Cultures for mycobacteria were performed and identification was done to species level by phenotypic and molecular tests. The outcome of the patients with NTM disease and related risk factors for poor outcome were evaluated.
  
  
  RESULTS
  Out of 117 consecutive strains isolated from suspected MDR-TB subjects, 35 (30%) strains were identified as NTM by using conventional and molecular approaches. Of these patients with positive NTM cultures, 32 (27%) patients met ATS/IDSA diagnostic criteria. Out of 32, 29 (90%) individuals with confirmed NTM diseases had underlying disorders including 8 subjects with malignancy, 5 with organ transplantations, and 4 with the human immunodeficiency virus. No known underlying disorder was found in 3 (9%) subjects. Treatment outcomes were available for 27 subjects, 17 (63%) of whom were cured and 10 (37%) had poor outcome including 6 (60%) who failed and 4 (40%) who died during treatment.
  
  
  CONCLUSIONS
  The high costs to the patient and society should lead health care providers to consider NTM in all patients suspected of having TB.
authors.affiliation: Department of Epidemiology, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Abdolrazagh Hashemi
authors.initials: AH
authors.lastname: Shahraki
authors.affiliation: Department of Microbiology, Alborz University of Medical Science, Karaj, Iran.
authors.forename: Parvin
authors.initials: P
authors.lastname: Heidarieh
authors.affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Saeed Zaker
authors.initials: SZ
authors.lastname: Bostanabad
authors.affiliation: Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Azar Dokht
authors.initials: AD
authors.lastname: Khosravi
authors.affiliation: Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hashemzadeh
authors.affiliation: Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Solmaz
authors.initials: S
authors.lastname: Khandan
authors.affiliation: Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Biranvand
authors.affiliation: Division of Pulmonary and Critical Care, University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: Dean E
authors.initials: DE
authors.lastname: Schraufnagel
authors.affiliation: Division of Pulmonary and Critical Care, University of Illinois at Chicago, Chicago, IL, USA. Electronic address: mmirsae@uic.edu.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mirsaeidi
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis*; D009170:Nontuberculous Mycobacteria / Q000145:classification / Q000302:isolation & purification*; D012189:Retrospective Studies; D012307:Risk Factors; D013183:Sputum; D016896:Treatment Outcome; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000382:microbiology
keywords: MDR-TB; NTM; Nontuberculous mycobacteria; Tuberculosis