title: Identification and genotyping of Mycobacterium tuberculosis isolated from water and soil samples of a metropolitan city.
abstract: BACKGROUND
  The potential role of environmental Mycobacterium tuberculosis in the epidemiology of TB remains unknown. We investigated the transmission of M tuberculosis from humans to the environment and the possible transmission of M tuberculosis from the environment to humans.
  
  
  METHODS
  A total of 1,500 samples were collected from three counties of the Tehran, Iran metropolitan area from February 2012 to January 2014. A total of 700 water samples (47%) and 800 soil samples (53%) were collected. Spoligotyping and the mycobacterial interspersed repetitive units-variable number of tandem repeats typing method were performed on DNA extracted from single colonies. Genotypes of M tuberculosis strains isolated from the environment were compared with the genotypes obtained from 55 patients with confirmed pulmonary TB diagnosed during the study period in the same three counties.
  
  
  RESULTS
  M tuberculosis was isolated from 11 of 800 soil samples (1%) and 71 of 700 water samples (10%). T family (56 of 82, 68%) followed by Delhi/CAS (11 of 82, 13.4%) were the most frequent M tuberculosis superfamilies in both water and soil samples. Overall, 27.7% of isolates in clusters were related. No related typing patterns were detected between soil, water, and clinical isolates. The most frequent superfamily of M tuberculosis in clinical isolates was Delhi/CAS (142, 30.3%) followed by NEW-1 (127, 27%). The bacilli in contaminated soil (36%) and damp water (8.4%) remained reculturable in some samples up to 9 months.
  
  
  CONCLUSIONS
  Although the dominant M tuberculosis superfamilies in soil and water did not correspond to the dominant M tuberculosis family in patients, the presence of circulating genotypes of M tuberculosis in soil and water highlight the risk of transmission.
authors.affiliation: From the Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Velayati
authors.affiliation: From the Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Parissa
authors.initials: P
authors.lastname: Farnia
authors.affiliation: From the Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohadese
authors.initials: M
authors.lastname: Mozafari
authors.affiliation: From the Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Donya
authors.initials: D
authors.lastname: Malekshahian
authors.affiliation: From the Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Amir Masoud
authors.initials: AM
authors.lastname: Farahbod
authors.affiliation: From the Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Shima
authors.initials: S
authors.lastname: Seif
authors.affiliation: From the Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Snaz
authors.initials: S
authors.lastname: Rahideh
authors.affiliation: Division of Pulmonary and Critical Care, University of Illinois at Chicago, Chicago, IL. Electronic address: mmirsae@uic.edu.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mirsaeidi
mesh_terms: D002947:Cities; D004269:DNA, Bacterial / Q000235:genetics*; D005500:Follow-Up Studies; D060005:Genotyping Techniques; D006801:Humans; D015994:Incidence; D007492:Iran / Q000453:epidemiology; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D012189:Retrospective Studies; D012988:Soil Microbiology / Q000592:standards*; D014376:Tuberculosis / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D014871:Water Microbiology / Q000592:standards*
chemical_list: D004269:DNA, Bacterial