Study of fluoroquinolones resistance in rifampicin-resistant tuberculosis patients in Beijing: Characteristics, trends, and treatment outcomes.

BACKGROUND

China is a high-burden country for multidrug-resistant tuberculosis/rifampin-resistant tuberculosis (MDR/RR-TB). Fluoroquinolones (FQs) are key drugs for the treatment of patients with MDR/RR-TB. However, research on the resistance of FQs in Beijing is limited.

METHODS

We collected clinical isolates from all patients with pulmonary TB in Beijing from January 2016 to December 2021, conducted drug-sensitivity tests and sequencing for levofloxacin (LFX) and moxifloxacin (MFX), and collected the treatment plans and outcomes of the patients.

RESULTS

A total of 8512 clinical isolates were collected from patients with pulmonary TB, and 261 RR-TB strains were screened. The proportions of drug-sensitive and drug-resistant strains significantly differed by age group and treatment history. The rates of LFX and MFX resistance were 27.6% (72/261) and 36.4% (95/261), respectively. The detection rates of MDR-TB and pre-extensively drug-resistant TB (pre-XDR-TB) were 73.2% (191/261) and 36.4% (95/261), respectively, and the trends were significant (χ trend = 9.995, p = 0.002; χ trend = 12.744, p = 0.026). Among the 261 RR-TB strains, 14.9% (24/261) were sensitive to LFX but resistant to MFX. Among the four patients with LFX-resistant TB who received LFX treatment failed in three patients(Fisher's exact test, p = 0.009). The common mutation sites were 94 and 90 in gyrA. A novel mutation Ala90Ser was discovered.

CONCLUSIONS

FQs resistance trends in RR-TB patients in Beijing are striking. Strains showed incomplete cross-resistance to LFX and MFX. Testing for FQs resistance and developing a reasonable treatment plan are recommended. Attention should be given to the changing trends in MDR-TB and pre-XDR-TB.