Beyond multidrug-resistant tuberculosis in Europe: a TBNET study

Area of Science:

• Microbiology
• Infectious Diseases
• Public Health

Background:

• Drug-resistant tuberculosis (TB) poses a significant threat to global public health and TB control efforts.
• The increasing prevalence of multidrug-resistant (MDR-TB), pre-extensively drug-resistant (pre-XDR-TB), and extensively drug-resistant (XDR-TB) strains complicates treatment regimens.
• Effective TB control strategies rely on accurate and timely drug susceptibility testing (DST).

Purpose of the Study:

• To evaluate the patterns of second-line drug susceptibility testing in Mycobacterium tuberculosis isolates from patients with drug-resistant TB in Europe.
• To assess the prevalence of resistance to key second-line anti-TB drugs among MDR-TB, pre-XDR-TB, and XDR-TB strains.
• To provide crucial data for informing treatment guidelines and TB control policies in Europe.

Main Methods:

• Second-line drug susceptibility testing was performed on Mycobacterium tuberculosis isolates.
• Isolates were obtained from patients diagnosed with multidrug-resistant, pre-extensively drug-resistant, and extensively drug-resistant TB.
• Data were collected from 23 TB Network (TBNET) sites across 16 European countries.

Main Results:

• Over 30% of pre-XDR-TB isolates exhibited resistance to fluoroquinolones.
• Nearly 70% of pre-XDR-TB isolates showed resistance to second-line injectable drugs.
• Phenotypic resistance to pyrazinamide and ethambutol was observed in over 90% and 80% of XDR-TB strains, respectively.
• High rates of resistance to prothionamide/ethionamide were noted in both pre-XDR-TB (43%) and XDR-TB (49%) patient isolates.

Conclusions:

• Significant levels of resistance to key second-line anti-TB drugs are prevalent in drug-resistant TB isolates in Europe.
• These findings underscore the urgent need for enhanced surveillance and development of novel therapeutic strategies for drug-resistant TB.
• The study emphasizes the critical role of comprehensive DST in guiding treatment decisions for complex TB cases.