Surveillance of multidrug-resistant tuberculosis in Taiwan, 2008-2019.

BACKGROUND: Drug-resistant tuberculosis (DR-TB) is a major contributor to global cases of antimicrobial resistance and remains a public health challenge. To understand the extent and trend of DR-TB under an enhanced multidrug-resistant TB (MDR-TB) management program, we conducted a population-based retrospective study of 1511 Taiwanese MDR-TB cases reported from 2008 to 2019. METHODS: We obtained patient demographics and clinical and bacteriological information from the National TB Registry and the Infectious Disease Notification System. RESULTS: Of the 1511 MDR-TB patients, 941 were new cases, 485 were previously treated, and 85 had an unknown history of treatment. The male to female ratio was 2.75, and the median age of the patients was 57 years (IQR: 45-72). We observed a significant decline in MDR-TB cases, with annual percentage change (APC) of -4.17%. However, new and previously treated MDR-TB cases had APCs of -1.41% and -9.18%, respectively. The rates of MDR-TB resistance to ethambutol, streptomycin and pyrazinamide were 47.2%, 42.4% and 28.9%, respectively, whereas the rates of resistance to fluoroquinolones and second-line injectable drugs (SLIDs) were 4.1-7.1%, 9.0-14.1%; and the rate of extensively drug-resistant TB was 1.9%, respectively. Furthermore, we observed a decreasing trend of resistance to SLIDs (APCs -7.0% to -8.2%) in new cases and a significant decreasing trend of resistance to moxifloxacin (-24.6%) and levofloxacin (-23.3%) in previously treated cases. CONCLUSION: The decreasing trend of MDR-TB and resistance to second-line drugs suggested that our programmatic management of TB was effective and that the impact on TB control was profound.

Primary Bedaquiline Resistance Among Cases of Drug-Resistant Tuberculosis in Taiwan.

Bedaquiline (BDQ), which is recommended for the treatment of drug-resistant tuberculosis (DR-TB), was introduced in Taiwan in 2014. Due to the alarming emergence of BDQ resistance, we conducted BDQ resistance analyses to strengthen our DR-TB management program. This retrospective population-based study included initial Mycobacterium tuberculosis isolates from 898 rifampicin-resistant (RR) or multidrug-resistant (MDR) TB cases never exposed to BDQ during 2008-2019. We randomly selected 65 isolates and identified 28 isolates with BDQ MIC<0.25µg/ml and MIC≥0.25µg/ml as the control and study groups, respectively. BDQ drug susceptibility testing (DST) using the MGIT960 system and Sanger sequencing of the atpE, Rv0678, and pepQ genes was conducted. Notably, 18 isolates with BDQ MIC=0.25µg/ml, 38.9% (7/18), and 61.1% (11/18) isolates were MGIT-BDQ resistant and susceptible, respectively. Consequently, we recommended redefining MIC=0.25µg/ml as an intermediate-susceptible category to resolve discordance between different DST methods. Of the 93 isolates, 22 isolates were MGIT-BDQ-resistant and 77.3% (17/22) of MGIT-BDQ-resistant isolates harbored Rv0678 mutations. After excluding 2 MGIT-BDQ-resistant isolates with borderline resistance (GU400growth control-GU100BDQ≤1day), 100% (15/15) harbored Rv0678 gene mutations, including seven novel mutations [g-14a, Ile80Ser (N=2), Phe100Tyr, Ala102Val, Ins g 181-182 frameshift mutation (N=2), Del 11-63 frameshift mutation, and whole gene deletion (N=2)]. Since the other 22.7% (5/22) MGIT-BDQ-resistant isolates with borderline resistance (GU400growth control-GU100BDQ≤1day) had no mutation in three analyzed genes. For isolates with phenotypic MGIT-BDQ borderline resistance, checking for GU differences or conducting genotypic analyses are suggested for ruling out BDQ resistance. In addition, we observed favorable outcomes among patients with BDQ-resistant isolates who received BDQ-containing regimens regardless of Rv0678 mutations. We concluded that based on MIC≥0.25µg/ml, 3.1% (28/898) of drug-resistant TB cases without BDQ exposure showed BDQ resistance, Rv0678 was not a robust marker of BDQ resistance, and its mutations were not associated with treatment outcomes.

Interactions of Genes and Sodium Intake on the Development of Hypertension: A Cohort-Based Case-Control Study.

There have been few studies investigating interactions of G-protein beta3 subunit (GNB3) C825T (rs5443) and dietary sodium intake on the risk of hypertension, i.e., BP salt sensitivity. The study aims to evaluate joint effects of GNB3 polymorphisms and sodium consumption on the development of hypertension. A cohort-based case-control study was conducted in 2014. There are 233 participants with newly diagnosed hypertension in the case group and 699 participants in the gender-matched control group. The primary outcome is the development of hypertension over a 10-year period. The determinants of hypertension were three genotypes of SNP in GNB3 (TT; CT; and CC) and two dietary salt categories on the basis of the level of sodium consumption representing high (>4800 mg/day) and low-sodium (.

Purification and characterization of an aspartic protease from the Rhizopus oryzae protease extract, Peptidase R

Background Aspartic proteases are a subfamily of endopeptidases that are useful in a variety of applications, especially in the food processing industry. Here we describe a novel aspartic protease that was purified from Peptidase R, a commercial protease preparation derived from Rhizopus oryzae. Results An aspartic protease sourced from Peptidase R was purified to homogeneity by anion exchange chromatography followed by polishing with a hydrophobic interaction chromatography column, resulting in a 3.4-fold increase in specific activity (57.5 × 10³ U/mg) and 58.8% recovery. The estimated molecular weight of the purified enzyme was 39 kDa. The N-terminal sequence of the purified protein exhibited 63-75% identity to rhizopuspepsins from various Rhizopus species. The enzyme exhibited maximal activity at 75°C in glycine-HCl buffer, pH 3.4 with casein as the substrate. The protease was stable at 35°C for 60 min and had an observed half-life of approximately 30 min at 45°C. Enzyme activity was not significantly inhibited by chelation with ethylenediamine tetraacetic acid (EDTA), and the addition of metal ions to EDTA-treated protease did not significantly change enzyme activity, indicating that proteolysis is not metal ion-dependent. The purified enzyme was completely inactivated by the aspartic protease inhibitor Pepstatin A. Conclusion Based on the observed enzyme activity, inhibition profile with Pepstatin A, and sequence similarity to other rhizopuspepsins, we have classified this enzyme as an aspartic protease.