NEW MICROBIOLOGICA, 35, 61-65, 2012 Genetic diversity of Iranian clinical isolates of Mycobacterium tuberculosis Abodolrazagh Hashemi 1 , Hasan Shojaei 2 , Parvin Heidarieh 1 , Mohamad Mehdi Aslani 3 , Abass Daei Naser 2 1 Infectious and Tropical Disease Research Center, Ahvaz Jundishapur University of Medical Sciences, Iran; 2 Infectious and Tropical Disease Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; 3 Bacteriology Department, Pasteur Institute of Iran INTRODUCTION Since the late 1980s, molecular methods have been gradually developed to study the genetic di- versity of Mycobacterium tuberculosis strains (Mathema et al., 2006). Several molecular ap- proaches such as restriction fragment length poly- morphism (RFLP) based on small transposable element IS6110, the direct repeat (DR), the GC- rich repetitive sequence (PGRS), variable num- bers of tandem repeat loci (VNTR) and single-nu- cleotide polymorphism (SNP) have been devel- oped for molecular fingerprinting of M. tubercu- losis isolates (van Embden et al., 1993; Yang et al., 1996; Heyderman et al., 1998; Sola et al., 2003; Corresponding author Hasan Shojaei Infectious and Tropical Disease Research Center Isfahan University of Medical Sciences, Isfahan, Iran E-mail: hasanshojaei@msn.com Gutacker et al., 2006; Supply et al., 2010). Most of these methods require high expertise, a well- equipped laboratory and relatively complex pro- tocols to clearly differentiate the various TB strains. In the current study we aimed to resolve the genetic diversity of Iranian isolates of Mycobacterium tuberculosis by using a rather less complicated molecular typing method, namely, RAPD analysis (Weish et al., 1990). MATERIALS AND METHODS Isolates A total of 96 isolates of M. tuberculosis corre- sponding to 96 independent patients with con- firmed tuberculosis infection referred to or iso- lated in our laboratory over a period of 6 years between 2002 to 2008 were investigated. The iso- lates originated from a variety of clinical speci- mens comprising sputum (51 cases), gastric In the current study we aimed to execute a rather less complicated molecular tying method, i.e. the random amplifi- cation of polymorphic DNA (RAPD) analysis to find the heterogeneity of Iranian strains of Mycobacterium tuberculo- sis. The isolates comprised a total of 96 strains of M. tuberculosis collected from clinical specimens of patients in Isfahan and Tehran. The isolates were assigned to the species M. tuberculosis by the key conventional and molecular methods. They were then subjected to RAPD analysis by four arbitrary primers, namely, the primers 27F, 1525R, MS- GF and INS-2. They were then evaluated for the number and intensity of the band patterns. The RAPD profiles of the Iranian isolates showed a degree of heterogeneity which varied based on the primer used. However, analysis of the iso- lates by primer INS-2 revealed the highest degree of diversity yielding 31 distinguishable RAPD types. RAPD analysis provides a rapid and easy means of identifying heterogeneity among the M. tuberculosis isolates. This typing system might be considered a valuable alternative molecular typing for countries with limited resources pro- vided that the reproducibility and reliability of the method is carefully assured. KEY WORDS: Mycobacterium tuberculosis, RAPD, Typing SUMMARY Received August 19, 2011 Accepted November 10, 2011