Abstract
Background: There is high prevalence of drug-resistant tuberculosis(TB) cases in Mumbai.Xpert MTB/RIF is a rapid and accurate point-of-care test for detecting MTB,and rifampicin(Rif) resistance.After diagnosis using Xpert MTB/RIF,phenotypic drug susceptibility testing(DST)results are available few weeks later.Patients have to be treated empirically with combinations of drugs,while awaiting DST reports.
Aim: To determine prevalence of drug resistance to 12 other drugs tested,when MTB strain is Rif-resistant.
Methods: Between June 2014-February 2015 consecutive 13-drug DSTs performed at microbiology laboratory at P.D.Hinduja Hospital, Mumbai were included.Prevalence of resistance to 12 drugs in presence of resistance to Rif was determined,and positive predictive value of Rif resistance in determining resistance to each of the other drugs was calculated.
Results: Resistance to rifampicin was detected in 238 of 423 samples analyzed(56.3%).Results are summarized.
Drug | No of resistant strains when Rif resistance detected(n=238) | Positive predictive value of Rifampicin resistance in predicting resistance %, 95% CI |
Isoniazid | 236(99%) | 99(97,100) |
Ethambutol | 185(78%) | 77(72,83) |
Pyrazinamide | 198(83%) | 83(78,88) |
Streptomycin | 221(93%) | 93(89,96) |
Kanamycin | 31(13%) | 13(9,18) |
Capreomycin | 15(6%) | 6(4,10) |
Amikacin | 19(8%) | 8(5,12) |
Ofloxacin | 165(69%) | 69(63,75) |
Moxifloxacin | 157(66%) | 66(60,72) |
Ethionamide | 143(60%) | 60(54,66) |
Para amino salicylic acid (PAS) | 35(15%) | 15(10,20) |
Clofazimine | 2(1%) | 1(0,3) |
Table 1
Discussion: In Indian setting,a combination of aminoglycoside,ethionamide,quinolone,PAS and Clofazimine would possibly be the best empiric treatment for rifampicin-resistant cases detected on Xpert MTB/RIF.
- Copyright ©ERS 2015