Molecular resistance of Ethambutol in clinical samples obtained from patients admitted to the health center in Ardabil province using MAS-PCR

Background. Global stop TB is a critical strategy which aims at reducing the incidence of tuberculosis to less than one case per one million people by 2050. To achieve this goal, it is necessary to establish a timely diagnosis of the disease, provide an effective treatment, and identify the drug-resistant strains. Therefore, this study aimed to identify the resistance to ethambutol in patients referred to Ardabil Health Center. Methods. In this descriptive cross-sectional study, 71 clinical samples were collected from the patients referred to Ardabil Health Center between 2017-2020. The samples were first examined adopting microscopic method, and then DNA was extracted using the boiling method. Specific primers and MAS-PCR technique were employed for identification of ethambutol resistance strains. Results. Out of 71 collected specimens, six samples were NTM (8.45%). Out of all the examined samples, 36 samples (50.7%) had embB306 gene mutation, of which three samples were NTM (total NTM resistance was 50%). Out of the samples identified as resistant to ethambutol, six samples had a low bacterial load as +1 (16.67%), eight samples had a moderate bacterial load as +2 (22.22%), and the rest had a high bacterial load as +3 (61.11%). Conclusion. In sum, the frequency of resistance to ethambutol was 50.7%, which was higher than that reported by previous similar studies. Furthermore, it was determined that the MAS-PCR method was a fast, cheap, and reliable method for identifying resistance to the first-line tuberculosis drugs such as ethambutol. Therefore, this method may have facilitated evaluating the resistance to other first-line drugs at the same time and preventing the spread of resistant strains in the community through early detection of the antibiotic resistance. Practical Implications. Our study results may have been useful in increasing the awareness among the physician and health care workers of the ethambutol resistance level in indigenous strains in Ardabil province.