These findings suggest that fluoroquinolone resistance is the result of treatment of patients with MDR strains rather than from use in the general community in Taiwan. The emergence of fluoroquinolone resistance among MDR strains reinforces the need for routine fluoroquinolone susceptibility testing whenever these drugs might be used.

A total of 76 clinical Mycobacterium tuberculosis isolates from Taiwan were tested for pyrazinamidase activity, pyrazinamide susceptibility, and pncA mutations. Frequency of resistance to PZA rose with increases in resistance to first-line drugs. Of 17 pyrazinamide-resistant strains, 7 (3 of which had not been previously described) possessed mutations in the pncA gene.

Accurately differentiating tuberculous pleurisy from lung cancer is important for disease management but difficult using conventional laboratory methods. This study assessed the value of adenosine deaminase (ADA) and interferon gamma (IFN-γ) for differentiating the two conditions in a region of Taiwan with a high prevalence of tuberculosis. The study population comprised patients with lymphocytic exudative pleural effusions: tuberculous (n=24) and malignant (n=42). Mean levels of ADA and IFN-γ in pleural fluid, measured with commercial standardized kits, were significantly higher for tuberculous than for malignant pleurisy (p<0.001 for both). For differentiating the two effusions, results for ADA versus IFN-γ were: sensitivity, 70.8% versus 91.7%; specificity, 95.2% versus 97.6%; positive predictive value, 89.5% versus 96.7%; and negative predictive value, 85.1% versus 95.3%. IFN-γ allows precise diagnosis of pleural tuberculosis, but ADA is easier to use, has a low cost, and results are quickly available. Our study confirms previous studies and extends the usefulness of these diagnostic methods to a wider group of clinical laboratories by showing the reliability of standardized relatively inexpensive commercial kits. We recommend that initial ADA screening be used in conjunction with IFN-γ measurements for differential diagnosis of tuberculous pleurisy.

Significant increases in the MICTuberculosis (TB) is one of the major causes of death worldwide. The global prevalence of mycobacterial infection has been estimated to be 32% (1.9 billion people), with 8 million new cases of TB diagnosed annually and an average case fatality rate of 23% (11). In the year 2003, the incidence and mortality rate of TB in Taiwan were reported at 62.38 and 5.80 per 100,000 people, respectively (2), and TB is considered a more serious public health problem in southern than in northern Taiwan.Although TB can be cured with chemotherapy, the treatment is exceedingly lengthy and results in poor patient compliance, which is a frequent cause of selection of drug-resistant and even multidrug-resistant (MDR) Mycobacterium tuberculosis complexes. If the treatment fails as a result of drug resistance, treatment with second-line drugs is necessary. In Taiwan, the overall rates of MDR M. tuberculosis among new cases and previously treated cases ranged from 1% to 3% and 15% to 46%, respectively (5). In our previous report, increases in the MIC 90 s and rates of resistance to ciprofloxacin, ofloxacin, and levofloxacin were noted in the MDR group (6). Therefore, there is an increasing need for new antimicrobial agents against MDR M. tuberculosis.

BackgroundRapid identification of mycobacteria is important for timely treatment and the implementation of public health measures. The MGIT system ensures rapid detection of mycobacteria, but identification is usually delayed by days to weeks due to further subculture on solid medium. Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) was demonstrated to effectively identify mycobacteria isolates subcultured from solid or liquid media. Reports of identification directly from MGIT broths of both sterile and non-sterile clinical specimens, omitting the subculture step, were limited and not satisfactory before. Our identification method dramatically shortened delay from detection to identification of mycobacteria.MethodologyWe assessed the performance of the Vitek MS IVD version 3.0 for direct identification of NTM and M.tuberculosis from primary MGIT cultures, and assessed two sample preparation methods.ResultsDirect identification of NTM from positive MGIT broths, using MALDI-TOF VITEK MS with IVD v.3.0, generated high rates of acceptable results reaching 96.4% (80/83), and up to 100% (83/83) for sample preparations including a 0.1% SDS washing step. The sensitivity of VITEK MS to identify M.tuberculosis from MGIT tubes was 58/72 (80.6%), when using immunochromatography (ICA) test as gold standard. A characteristic colony clumping, wool-like appearance was observed in 48, and all 58 (100%) were correctly identified as M.tuberculosis using MALDI-TOF. The detection rate of M.tuberculosis complex was low (10/24, 41.6%) in the 24 MGIT tubes that was polymicrobial. Our method significantly reduced both the reagent cost and turnaround time.ConclusionsBased on a simplified protocol, we showed that MALDI-TOF MS can be used for rapid identification of NTM directly from primary MGIT cultures within the routine clinical laboratory workflow. However, we recommend an initial ICA test to screen for M.tuberculosis complex, due to a low identification rate of M. tuberculosis in the presence of polymicrobial cultures using MALDI-TOF.