Molecular Identification of Clinical Isolates of Mycobacterium fortuitum by Random Amplified Polymorphic DNA (RAPD) Polymerase Chain Reaction and ERIC PCR.

Abstract

Non tuberculous mycobacteria (NTM) are of importance now-a-days due to their increasing virulence outbreaks and emerging antibiotic resistance. Since the most common NTM in Iran is reportedly Mycobacterium fortuitum, the present study was designed with the aim of molecular identification of clinical isolates of M. foruitum to analyse their heterogeneity. A total of 81 isolates of NTM isolated from various samples were collected. The clinical isolates were assigned to species M. fortuitum by using conventional and molecular methods. The DNA banding patterns of ERIC- PCR and RAPD- PCR were analysed by using Bionumeric 7.5 software. Out of 81 tested NTM, 36 strains of M. fortuitum were identified. 33 isolates were selected for molecular typing in this study. Based on RAPD and ERIC analysis, M. fortuitum isolates were divided into 3 and 6 clusters, respectively. Most of the isolates were distributed into types of II RAPD (20 members/ 60.6 %) and V (14 members/ 42.4% with sub cluster I & II) of ERIC. In RAPD analysis, the major fragments were 300 bp, followed by fragment 1000. In ERIC analysis, the major fragments were 280 bp followed by fragment 1200 bp. In conclusion, though the results from this study represented higher discriminatory power of ERIC, however the combination of RAPD and ERIC analysis were able to sufficiently discriminate the genotypic diversity, infection control, and gain useful epidemiological information regarding M. fortuitum isolates.