gh BIOCHIP TO DIAGNOSE MYCOBACTERIA’S MULTIPLE DRUG RESISTANCE

Specialists of the Moscow Scientific Practical Center for Fighting against Tuberculosis (Department of Public Health of Moscow) and the V.A. Engelhardt Institute of Molecular Biology (Russian Academy of Sciences) have created a microchip that enables to determine tuberculosis pathogens’ sensitivity to drugs.

In recent years, physicians have increasingly often recorded cultures of tuberculous bacteria resistant to both main antituberculous preparations: fluoroquinolones - rifampicin and isoniazid. Among the Muscovites diseased for the first time, 8% to 10% are infected with mycobacteria with multiple drug resistance, among chronic patients – up to 25%. In the Russian Federation, the share of such patients is approximately twice as high. If physicians fail to timely determine that the patient is infected with resistant bacteria, they start to treat the patient by standard drugs - rifampicin and isoniazid. This treatment, naturally, does not help the patient, besides he/she becomes an infection-breeder, the infection being resistant to main antituberculous drugs. In the meantime, phthisiatricians also have other drugs at their disposal, for example, moxifloxacin or levofloxacin, which efficiently cope with mycobacteria. They are to be prescribed in proper time, and to this end, physicians need a quick and efficient diagnostics method for multiple drug resistance.

Specialists of the Institute of Molecular Biology have recently developed a new test-system called TB-BIOCHIP-2 that enables (via analyzing mycobacteria’s DNA) to identify 9 types of mutation in the gyrA gene, which evoke resistance to fluoroquinolones. The diagnostic method was tested in the Moscow Scientific Practical Center for Fighting against Tuberculosis (Department of Public Health of Moscow). Physicians studied phlegm and other diagnostic materials obtained from 137 patients ill with tuberculosis and those from 32 patients suffering from non-tubercular lung diseases. Part of materials was investigated with the help of biological microchips, the other part – by traditional microbiological methods by plating into special nutrient media. The outcomes received via both methods did coincide. However, it takes at least a month to identify mycobacteria’s sensitivity to fluoroquinolones on nutrient media, but in case of the biochip analysis – it takes only 48 hours, including processing of material. Therefore, the TB-BIOCHIP-2 test-system enables not only to identify initial mycobacteria’s sensitivity to drugs, but also to continuously track if tuberculosis pathogens acquire fluoroquinolones resistance in the course of treatment.

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