Identification of Antibiotic-Resistant Genes and Effect of Garlic Ethanolic Extract on Mycobacterium tuberculosis Isolated from Patients in Zabol, Iran

Mycobacterium is a genus of Actinobacteriaceae and the Mycobacterium family, including important pathogens, such as Mycobacterium tuberculosis (i.e., the cause of tuberculosis) and Mycobacterium leprae (i.e., the cause of leprosy). Tuberculosis is still a major cause of death in human societies.

The current study aimed to evaluate the effect of ethanolic extract of garlic on Mycobacterium tuberculosis isolated from patients in Zabol, Iran, and investigate the presence of antibiotic-resistant genes in Mycobacterium tuberculosis.

Garlic (Allium sativum) was collected from Zabol, and the ethanolic extract of garlic leaf was obtained. In this study, 50 strains of Mycobacterium tuberculosis were obtained from the patients in Zabol. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Some antibiotics, such as isoniazid, pyrazinamide, ethambutol, amikacin, streptomycin, and rifampicin, were used for positive control. Genomic deoxyribonucleic acid was extracted by the sodium dodecyl sulfate method. Furthermore, the presence of antibiotic-resistant genes, namely KatG, PncA, embC, embA1, embA2, embB1, embB2, rrs, rpsL, and ropB, in Mycobacterium tuberculosis was investigated using polymerase chain reaction.

The lowest MIC and MBC of garlic ethanolic extract against Mycobacterium tuberculosis were 3.25 and 7.5 ppm, respectively. The highest MIC and MBC were 60 and 120 ppm, respectively. Following the investigation of the presence of antibiotic-resistant genes in Mycobacterium tuberculosis, it was determined that it contains KatG, PncA, embC, embA1, embA2, ropB, rpsL, rrs, embB2, and embB1 genes. The highest resistance of Mycobacterium tuberculosis was against rifampin (81%) and then amikacin (76.6%) belonging to ropB and rrs genes, respectively.

The results of the present study showed that the ethanolic extract of garlic was very effective in Mycobacterium tuberculosis and the most effective genes in mycobacteria were ropB and rrs. Although garlic is very effective in Mycobacterium tuberculosis, it is not recommended to directly use the results of this study. Therefore, it is required to perform clinical trials to confirm the results.