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Background/aims: We evaluated the trend in the rates of drug-resistant tuberculosis (TB) over time, as well as the difference in the drug-resistance pattern between pulmonary tuberculosis (PTB) and extrapulmonary tuberculosis (EPTB) at a private referral center in South Korea., Methods: All patients with culture-confirmed TB from 2006 to 2013 were included., Results: In total, 1,745 patients were included: 1,431 (82.0%) were new cases, and 314 (18.0%) were cases treated previously; 1,610 (92.3%) were diagnosed with PTB, and 135 (7.7%) were diagnosed with EPTB. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB were detected in 5.8% and 2.0% of new cases and in 20.1% and 8.6% of previously treated cases, respectively. The MDR TB rate during the study period decreased remarkably, whereas the MDR and XDR TB rates decreased significantly in previously treated cases. No difference in the drug-resistance rate was detected between PTB and EPTB., Conclusions: The TB drug-resistance rate, particularly that of MDR TB, remained high at a private referral hospital, and the drug-resistance rate did not decrease significantly from 2006 to 2013. This finding underscores the need for a national survey regarding the prevalence of drug-resistant TB to obtain the most accurate and current drug-resistance status in South Korea, including the private sector.

BackgroundThe aim of this study was to evaluate the diagnostic accuracy of the GenoType MTBDRplusassay in detecting drug-resistant tuberculosis (DR-TB) by using acid-fast bacilli (AFB) smear-negative specimens with positive TB-PCR results.MethodsThe MTBDRplusassay was performed with 2 different categories of 117 samples, including AFB smear-positive specimens (n = 53) and AFB smear-negative specimens (n = 64), which exhibited positive TB-PCR results, at a single institution. The results were retrospectively compared with the results of the phenotypic drug susceptibility test (DST), for reference.ResultsA total of 105 tests were finally analyzed. Of these, 54 tests were conducted using AFB smear-negative specimens with positive TB-PCR results. The MTBDRplusassay for these 54 samples demonstrated a sensitivity of 100%, specificity of 98%, positive predictive value (PPV) of 75%, and negative predictive value (NPV) of 100% in detecting rifampicin resistance. With these same species, the sensitivity, specificity, PPV, and NPV values for the MTBDRplusassay were 83.3%, 97.9%, 83.3%, and 97.9%, respectively, for the detection of isoniazid resistance. The overall correlation between the MTBDRplusassay and phenotypic DST demonstrated excellent agreement for detection of rifampicin resistance (κ = 0.847) and for detection of INH resistance (κ = 0.812), respectively.ConclusionsThe MTBDRplusassay can be used effectively even on AFB smear-negative specimens from TB patients, when the TB-PCR is positive. This result might help clinicians to manage patients with suspected DR-TB in difficult situations. [ABSTRACT FROM AUTHOR]