title: Diversity and frequency of Nocardia spp. in the soil of Isfahan province, Iran.
abstract: OBJECTIVE
  To isolate and identify Nocardia spp. from soil in different regions of Isfahan province in the center of Iran.
  
  
  METHODS
  This study was conducted in 32 districts (16 cities and 16 villages) in Isfahan province during two years. A total of 800 soil samples from these regions were studied by using kanamycin. The isolated Nocardia species were examined by gram and acid-fast staining and were identified biochemically and morphologically. The frequency and distribution of Nocardia spp. were determined in relation to different factors such as soil pH and temperate climate.
  
  
  RESULTS
  From 153 (19.1%) Nocardia isolates identified, Nocardia asteroids (N. asteroids) complex (45.5%) and Nocardia brasiliensis (N. brasiliensis) (24.7%) were the most frequently isolated species, followed by Nocardia otitidiscaviarum (2.2%), Nocardiopsis dassonvillei, Actinomadura actinomadura (each 1.7%) and Nocardia transvalensis (1.1%) and also unknown spp. (23.0%). In this study, most species (54.4%) of Nocardia, especially N. asteroides complex were isolated from soils with pH: 7.01-8, whereas in pH: 8.01-9 more N. brasiliensis was isolated. The most Nocardia spp. was detected from regions with semi-nomadic and temperate climate (41.1%).
  
  
  CONCLUSIONS
  N. asteroids complex is more prevalent in Isfahan province and soil can be a potential source of nocardiosis infections. It is to be considering that climate and soil pH are involved in the frequency and diversity of aerobic Actinomycetes.
authors.affiliation: Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: R
authors.initials: R
authors.lastname: Kachuei
authors.forename: M
authors.initials: M
authors.lastname: Emami
authors.forename: R
authors.initials: R
authors.lastname: Mirnejad
authors.forename: M
authors.initials: M
authors.lastname: Khoobdel
mesh_terms: D001431:Bacteriological Techniques; D044822:Biodiversity; D006863:Hydrogen-Ion Concentration; D007492:Iran; D009615:Nocardia / Q000145:classification* / Q000302:isolation & purification*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D013696:Temperature
chemical_list: D012987:Soil
keywords: Actinomycetes; Climate; Iran; Isfahan; Nocardia; Nocardia asteroids; Nocardiosis; Soil microbiology