Molecular Identification and Conventional Susceptibility Testing of Iranian Clinical Mycobacterium fortuitum Isolates

Objective(s) Rapidly growing mycobacteria (RGM) are capable of producing diseases in humans. Since mycobacteria vary in their susceptibility, precise identification is critical for adoption of correct drug therapy. The main aim of this study was molecular identification and evaluation of antimicrobial susceptibility pattern of Iranian clinically isolated Myocbacterium fortuitum. Materials and Methods A total of ۷۲ presumptively identified isolates of clinical atypical mycobacteria collected by Isfahan Research Center for Infectious Diseases & Tropical Medicine during ۲۰۰۶-۲۰۰۸ were included in the current study. A combination of conventional and molecular tests was applied to identify the isolates. Molecular methods including genus and group specific PCR and PCR-Restriction Algorithm (PRA) based on hsp۶۵ gene were applied to achieve exact identification of mycobacterial strains. Antimicrobial susceptibility testing onM. fortuitum isolates was performed by in-house prepared broth microdilution test.. Results Out of ۷۲ collected atypical mycobacteria isolates, we identified ۲۵ strains of M. fortuitum. All strains had the specific molecular markers of mycobacterial identity and similar species specific PRA pattern of the international type strain of M. fortuitum. Drug susceptibility testing showed that the M. fortuitum isolates are sensitive to amikacin, sulfamethoxazole and ciprofloxacin (۱۰۰%), imipenem (۹۲%), clarithromycin (۷۶%), cefoxitin (۵۶%) and doxycycline (۱۶%). Conclusion Molecular identification of atypical mycobacteria based on PRA is a reliable and rapid approach which can identify mycobacterial strains to the species level. Our study showed that M. fortuitum plays a significant role in pulmonary and extrapulmonary infection in patients and should be given proper considerations when clinical samples are processed.

کلیدواژه ها:

Broth microdilution ، identification ، Mycobacterium ، Susceptibility test ، Heat shock protein gene (hsp۶۵)