To determine the prevalence of tuberculosis caused by a broad-spectrum antibacterial drug-resistant pathogen, scientists from Atlanta studied sputum culture results from 1,278 adult patients with multidrug-resistant tuberculosis (MDR) for susceptibility to 11 first and second line anti-tuberculosis drugs. Sputum samples were taken from patients in 8 countries (Estonia, Latvia, Peru, Philippines, USA, South Africa, South Korea and Thailand).

The researchers also used the data to determine risk factors for developing resistance to second-line drugs in patients with MDR-TB.

According to scientists, the widespread spread of mycobacteria with resistance to broad-spectrum antibacterial drugs heralds the emergence of tuberculosis that is almost impossible to treat worldwide.

Multi-drug resistant tuberculosis is caused by Mycobacterium tuberculosis, which is resistant to at least isoniazid and rifampicin.

Tuberculosis resistant to treatment with broad spectrum drugs is caused by M. tuberculosis, resistant to isoniazid, rifampicin and at least 1 of the broad spectrum antibacterials, including fluoroquinolones, and 1 injectable anti-tuberculosis antibiotic. Fluoroquinolones and injectable antibiotics are second-line drugs for the treatment of tuberculosis.

According to Swedish researchers, most international recommendations for the treatment of tuberculosis have been developed to limit the prevalence of multidrug-resistant tuberculosis to 5%. However, scientists are now confronted with the prevalence of the disease, which in several regions is ten times higher than this figure, where polyresistant strains M. are detected in almost half of the patients. tuberculosis.

Researchers identified multidrug-resistant TB pathogens in 1,278 of the 1,540 original isolates. Of these 1,278 patients, 1,199 (93.8%) had a history of tuberculosis, and this indicator ranged from 47.8% to 100%, depending on the country. Most (70.6%) of the 1199 patients have had 1 to 2 confirmed episodes of tuberculosis in history. Almost all patients in the study (92.8%) received first-line anti-tuberculosis drugs before being included in the study, while only 195 patients (15.3%) received second-line drugs intention. Prescription rates for second-line antibiotics ranged from 2.7% in South Africa to 53.5% in South Korea.

There were significant differences in the prevalence of antibiotic resistance between different countries. Of the 1278 isolates, 625 (49%) were resistant to ethambutol and streptomycin in addition to isoniazid and rifampicin. Almost half of patients (43.7%) had pathogens resistant to at least one of the second-line drugs, and this indicator varied from country to country - from 33.3% in Thailand to 62% in Latvia. The average resistance level of mycobacteria to fluoroquinolones was 12.9%, the lowest was recorded in the Philippines (7.1%) and the highest in South Korea (32.3%). The average level of resistance to at least one of the second-line injectables was 20%, with the lowest rate observed in the Philippines (2%) and the highest in Latvia (47%).

In the Eastern Cape of South Africa, the prevalence of resistance to the three second-line injectable antibiotics was significantly higher than in the other South African provinces (65 [48.9%] out of 133 versus 10 [6, 3%] on 160 patients, p minus 0.0001).

In all countries, pathogens resistant to other oral drugs have been identified with a total prevalence of 27.1% (range: 13.0% -38.0%). Of 1278 patients in general, the causative agent of broad-spectrum antibiotic-resistant tuberculosis was detected in 86 (6.7%); prevalence of M. broad spectrum tuberculosis was lowest in the Philippines and highest in South Korea.

According to the World Health Organization, 5.4% of patients with MDR-TB have a pathogen resistant to a wide range of drugs. According to scientists, the higher incidence rate identified in this study may be the result of differences in laboratory studies. In the study presented, the three injectable drugs were evaluated, while in most countries one or two antibiotics were studied, which underestimates the prevalence of multidrug-resistant tuberculosis. Previous treatment with second-line drugs increased the risk of isolating mycobacteria resistant to broad-spectrum antibiotics by more than 4 times.

According to scientists, the results of the study help raise awareness of clinical practices and public health related to sustainable M. tuberculosis, as well as the identification of differences in prevalence and risk factors between countries. The data obtained can help to determine the most optimal approaches for the control of multidrug-resistant tuberculosis under specific epidemiological conditions.

Updating information on MDR-TB and exploring possible directions for disease development appears necessary, especially since the true prevalence rates of MDR-TB and mycobacteria resistant to broad spectrum drugs have been underestimated and are currently growing rapidly.