Mycobacterium simiae Isolates Subtypes and Molecular Drug Susceptibility in Iran

Despite the clinical and epidemiological importance of Mycobacterium simiae worldwide, including in Iran, there is no clear and effective treatment regimen for M. simiae and its different subtypes.

Concerning the superiority of molecular approaches, this study aims to identify the common M. simiae subtypes submitted to the National Reference Tuberculosis (TB) Laboratory of Iran and study the presence of drug resistance by molecular detection methods.

We included sputum samples with M. simiae confirmation submitted to the National Reference TB Laboratory of Iran from May 2014 to May 2016. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used for drug susceptibility testing (DST).

Among 7200 TB suspected patients, a total of 60 M. simiae cases belonging to subtype I were identified. All the included clinical isolates met the American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) diagnostic criteria and were considered the disease’s causative pathogen. Males (58.33%), elderly (68.54%), and patients with a history of TB (51.42%) were shown to be more prone to infection with the disease. All clinical isolates of M. simiae were resistant to rifampin (RIF) and isoniazid (INH). Amikacin/kanamycin (AMK/KAN) and ciprofloxacin (CIP) susceptibility was found to be 91.66% and 88.33%, respectively.

Subtype I was exclusively identified among M. simiae patients in Iran. Molecular detection of drug resistance suggests that amikacin/kanamycin and ciprofloxacin could be used to treat patients infected with M. simiae subtype I.