title: Prevalence of nontuberculous mycobacteria isolated from environmental samples in Iran: A meta-analysis.
abstract: BACKGROUND
  While the most nontuberculous mycobacteria (NTMs) species are considered as opportunistic pathogens, some of them are related to several human infections. It is believed that environment is the main source for these infections. Distribution and scattering pattern of NTMs has not been well studied in Iran and a few studies about this subject have been done, so the aim of this study was to determine prevalence of NTMs in environmental samples from Iran.
  
  
  METHODS
  Data about prevalence of NTMs in environmental samples from Iran were obtained by searching databases. The studies presenting cross-sectional or cohort and the papers with sample size ≥30 were included. Then, the meta-analysis was performed using Comprehensive Meta-Analysis software and Cochran's Q andI2tests. The strategy search was based PRISMA protocol is available online (PRISMA, http://www.prisma-statement.org).
  
  
  RESULTS
  The results of this meta-analysis showed that overall combined prevalence of NTMs in environmental samples from Iran was 38.3%. The frequency of NTM was higher in the north of Iran (73.2%). The most prevalent rapid-growing mycobacterium wasMycobacterium fortuitum(19.8%), and the most dominant slow-growing mycobacterium wasMycobacterium flavescens(16.8%).
  
  
  CONCLUSIONS
  In regard to increasing incidence of disease in immunocompromised patients and existence of different types of mycobacteria species in environmental samples, efforts should be focused on measures that will specifically remove NTMs from habitats where susceptible individuals are exposed.
authors.affiliation: Department of Microbiology and Virology, Antimicrobial Resistance Research Center, Avicenna Research Institute, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Azad
authors.initials: A
authors.lastname: Khaledi
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Bahador
authors.affiliation: Department of Microbiology, Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Davood
authors.initials: D
authors.lastname: Esmaeili
authors.affiliation: Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Tafazoli
authors.affiliation: Department of Microbiology and Virology, Antimicrobial Resistance Research Center, Avicenna Research Institute, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Kiarash
authors.initials: K
authors.lastname: Ghazvini
authors.affiliation: Department of Microbiology and Virology, Antimicrobial Resistance Research Center, Avicenna Research Institute, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Davood
authors.initials: D
authors.lastname: Mansury
keywords: Meta-analysis; nontuberculous mycobacteria; prevalence