Nishtha Singh1, Pravin Kumar Singh1, Urmila Singh1, Rajiv Garg2, Amita Jain3. 1. Department of Microbiology, King George's Medical University, Lucknow, Uttar Pradesh 226003, India. 2. Department of Respiratory Medicine, King George's Medical University, Lucknow, Uttar Pradesh 226003, India. 3. Department of Microbiology, King George's Medical University, Lucknow, Uttar Pradesh 226003, India. Electronic address: amitajain@kgmcindia.edu.
Abstract
OBJECTIVES: Sputum culture conversion at the end of the intensive phase of multidrug-resistant tuberculosis (MDR-TB) treatment is a key predictor for successful treatment outcome. This observational study was undertaken to assess the interim microbiological outcome of a cohort of rifampicin-resistant (RR)-TB patients with variable resistance to second-line drugs. METHODS: During Jan-Apr 2018, we consecutively enrolled 100 RR-TB patients, who underwent phenotypic drug susceptibility testing (DST) to assess baseline resistance to second-line drugs. Following RR-TB diagnosis, these patients were started on MDR-TB treatment. After 6 months of treatment, sputum culture conversion status was determined. Data were analysed to assess the impact of resistance to second-line drugs on culture conversion. RESULTS: DST of 100 RR-TB patients showed a high resistance to fluoroquinolones (FQs; levofloxacin 56%; moxifloxacin 44%) followed by kanamycin (8%) and capreomycin (6%). None of the patients were resistant to the other drugs tested (amikacin, clofazimine and linezolid). At 6-month treatment follow-up, 28 patients had been lost to follow-up and eight had died. Microbiological outcome was obtained from the remaining 64 patients, but successful culture conversion was achieved in only 62.5% of the patients. FQ resistance was found to be a strong predictor (P<0.001) for unfavourable microbiological outcome. CONCLUSION: The rate of FQ resistance in RR/MDR-TB is high and has strong association with unsuccessful interim microbiological outcome of conventional MDR-TB treatment.
OBJECTIVES: Sputum culture conversion at the end of the intensive phase of multidrug-resistant tuberculosis (MDR-TB) treatment is a key predictor for successful treatment outcome. This observational study was undertaken to assess the interim microbiological outcome of a cohort of rifampicin-resistant (RR)-TB patients with variable resistance to second-line drugs. METHODS: During Jan-Apr 2018, we consecutively enrolled 100 RR-TB patients, who underwent phenotypic drug susceptibility testing (DST) to assess baseline resistance to second-line drugs. Following RR-TB diagnosis, these patients were started on MDR-TB treatment. After 6 months of treatment, sputum culture conversion status was determined. Data were analysed to assess the impact of resistance to second-line drugs on culture conversion. RESULTS: DST of 100 RR-TB patients showed a high resistance to fluoroquinolones (FQs; levofloxacin 56%; moxifloxacin 44%) followed by kanamycin (8%) and capreomycin (6%). None of the patients were resistant to the other drugs tested (amikacin, clofazimine and linezolid). At 6-month treatment follow-up, 28 patients had been lost to follow-up and eight had died. Microbiological outcome was obtained from the remaining 64 patients, but successful culture conversion was achieved in only 62.5% of the patients. FQ resistance was found to be a strong predictor (P<0.001) for unfavourable microbiological outcome. CONCLUSION: The rate of FQ resistance in RR/MDR-TB is high and has strong association with unsuccessful interim microbiological outcome of conventional MDR-TB treatment.