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Background: Screening for Tuberculosis (TB) is a critical tactic for minimizing the prevalence of illness within schools. Tuberculosis Preventive Therapy (TPT), in turn, effectively staves off the development of TB from latent tuberculosis infection (LTBI). Unfortunately, there is limited research on LTBI and TPT among students. This study aimed to assess LTBI among freshmen in Changping District and advocate for the implementation of TPT. Methods: The prospective study collected data from 12 educational institutions within the Changping District of Beijing. The Kolmogorov − Smirnov test and other statistical methods were used for statistical analysis, x 2 was obtained using the formula x 2 = nΣA2/nRnC-1, df = (C-1) (R-1). We analyzed potential factors impacting the LTBI rate, and scrutinized the possible causes behind the low application of TPT and its efficacy for LTBI treatment, China. Results: Among 19,872 freshmen included in this study, 18 active TB cases (91 per 10,0000) and 2236 LTBI cases (11.6% of 19,223) were identified, respectively. Furthermore, of those with LTBI, 1045 (5.4% of 19,223) showed a strong positive for purified protein derivative (PPD), but only 312 opted for TB preventive treatment. There appeared to be no significant difference in the prevalence of LTBI and TPT rate between male and female students. Concurrently, 11 (71 per 100,000) and 7 (158 per 100,000) cases of active tuberculosis were identified in 6 universities and 6 higher vocational colleges, respectively. Interestingly, almost all freshmen who underwent TPT came from universities, suggesting a statistically significant disparity in TPT rate (χ2 = 139.829, P < 0.001) between these two types of educational institutions. Meanwhile, as for the age-wise distribution of latent infection among 17–20 years old freshmen, the LTBI rate exhibited 10.5%, 11.6%, 12.1% and 13.5%, respectively. Correlation between LTBI rate, the strong positive rate was statistically significant among different ages (χ2 = 34.559, P < 0.001). Over a follow-up period of 2 years, three students were diagnosed with active tuberculosis, one of which was resistant to rifampicin. All three students manifested a strong positive for PPD and declined preventive treatment during TB screening. Conclusions: The data indicates a high rate of LTBI amongst students in areas with a heavy TB burden, potentially leading to cross-regional TB transmission due to the migration of students. Education level might contribute to the limited uptake of TPT. Therefore, improving the implementation of TB preventive treatments is crucial in controlling and preventing TB across schools. [ABSTRACT FROM AUTHOR]

• Fate of nine tri-OPFRs in sludge was studied in a WWTP in Beijing, China. • Sludge contained high concentrations of tri-OPFRs (971.48–1,702.22 ng/g). • Mass flow of tri-OPFRs showed seasonal decreases. • The dehydration unit removed the most tri-OPFRs during sludge treatment. • Ecological risk of OPFRs in treated sludge was reduced. Organophosphate flame retardants (OPFRs) are emerging environmental pollutants that cause endocrine disruption, neurotoxicity, and reproductive toxicity. Sewage sludge is an important source of tri-OPFRs that are released into the environment. The occurrence, distribution, and ecological risk of OPFRs in the full-scale "Cambi® thermal hydrolysis (TH) + advanced anaerobic digestion (AAD) + plate-frame pressure filtration" sludge treatment process is closely related to the application of sewage sludge. We tested sludge samples from a wastewater treatment plant in Beijing, China. Nine tri-OPFRs were detected in the sludge samples collected at different treatment units during four seasons. The ΣOPFRs decreased from 1,742.65–2,579.68 ng/g to 971.48–1,702.22 ng/g. The mass flow of tri-OPFRs in treated sludge decreased by 61.4%, 48.9%, 42.4%, and 63.9% in spring, summer, autumn and winter, respectively, effectively reducing the corresponding ecological risk. The ecological risk of tri-OPFRs in sludge in forestland utilization mainly lies in chlorinated tri-OPFRs, especially TCPP and TCEP. No >42.20 t/hm2 of sludge could be used continuously for one year to prevent tri-OPFRs from exceeding the low ecological risk level, indicating that the current commonly applied proportion of sludge (1.6–30 t/hm2) will likely not raise the ecological risk of tri-OPFRs. [ABSTRACT FROM AUTHOR]

Background: Pyrazinamide still may be a useful drug for treatment of rifampin-resistant (RR-TB) or multidrug-resistant tuberculosis (MDR-TB) in China while awaiting scale up of new drugs and regimens including bedaquiline and linezolid. The level of pyrazinamide resistance among MDR-TB patients in China is not well established. Therefore, we assessed pyrazinamide resistance in a representative sample and explored determinants and patterns of pncA mutations.Methods: MDR-TB isolates from the 2007 national drug resistance survey of China were sub-cultured and examined for pyrazinamide susceptibility by BACTEC MGIT 960 method. pncA mutations were identified by sequencing. Characteristics associated with pyrazinamide resistance were analyzed using univariable and multivariable log-binominal regression.Results: Of 401 MDR-TB isolates, 324 were successfully sub-cultured and underwent drug susceptibility testing. Pyrazinamide resistance was prevalent in 40.7% of samples, similarly among new and previously treated MDR-TB patients. Pyrazinamide resistance in MDR-TB patients was associated with lower age (adjusted OR 0.54; 95% CI, 0.34-0.87 for those aged ≧60 years compared to < 40 years). Pyrazinamide resistance was not associated with gender, residential area, previous treatment history and Beijing genotype. Of 132 patients with pyrazinamide resistant MDR-TB, 97 (73.5%) had a mutation in the pncA gene; with 61 different point mutations causing amino acid change, and 11 frameshifts in the pncA gene. The mutations were scattered throughout the whole pncA gene and no hot spot region was identified.Conclusions: Pyrazinamide resistance among MDR-TB patients in China is common, although less so in elderly patients. Therefore, pyrazinamide should only be used for treatment of RR/MDR-TB in China if susceptibility is confirmed. Molecular testing for detection of pyrazinamide resistance only based on pncA mutations has certain value for the rapid detection of pyrazinamide resistance in MDR-TB strains but other gene mutations conferring to pyrazinamide resistance still need to be explored to increase its predictive ability . [ABSTRACT FROM AUTHOR]

Objectives This study examined the phenomenon of heteroresistance in Mycobacterium tuberculosis clinical isolates obtained from retreated patients in Beijing, China between 2006 and 2011. Methods The iPLEX Gold assay platform was used to determine the prevalence of heteroresistance to injectable second-line drugs (amikacin, kanamycin and capreomycin) in resistant isolates. Results Heteroresistance was identified in 10.9% of 220 phenotypic amikacin-resistant isolates. Conclusions Heteroresistance was related mainly to the short duration and repeated use of amikacin and capreomycin during retreatment. These findings further our understanding of the evolution of resistance to injectable drugs used for tuberculosis treatment and help guide the rational use of injectable drugs during therapy. [ABSTRACT FROM PUBLISHER]

The emergence of extensively drug-resistant tuberculosis (XDR-TB) in China is a great threat to TB control. To determine the molecular characterisation of XDR-TB isolates from China and the correlations between specific drug resistance-associated mutations and different genotype strains, 58 XDR-TB isolates were sequenced in eight drug loci, including katG , inhA , oxyR–ahpC intergenic region, rpoB , eis , rrs , gyrA and gyrB , and were genotyped using spoligotyping and analysis of the noise transfer function region. Compared with the phenotypic data, the sensitivities and specificities for DNA sequencing were 87.9% and 100.0% for isoniazid (INH), 91.4% and 98.3% for rifampicin (RIF), 60.4% and 100.0% for kanamycin (KAN) and 81.0% and 100.0% for ofloxacin (OFX), respectively. A combination of eight drug loci predicted XDR-TB phenotypes with 53.4% sensitivity (31/58 isolates) and 100.0% specificity. The most frequent mutations among these XDR-TB isolates were katG 315 and inhA -15 (for INH), 531, 526 and 516 in rpoB (for RIF), rrs 1401 and eis –10 (for KAN) and 94, 90 and 91 in gyrA (for OFX). Also, among these XDR-TB isolates, 44 (75.9%) were identified as Beijing genotype strain, of which 31 (70.5%) belonged to the modern Beijing sublineage. inhA -8, rpoB 526 and rpoB 531 mutations demonstrated significant statistical associations with ancient and modern Beijing family sublineage ( P < 0.05). However, Beijing and non-Beijing genotypes showed no association with specific resistance-conferring mutations. These results will be helpful in designing new molecular biology-based techniques to diagnose XDR-TB in China. [ABSTRACT FROM AUTHOR]

Chinese indigenous pork is preferred by consumers because of its unique nutritional and flavor characteristics. The aim of this study was to investigate the fatty acid contents and reheating volatile compounds (i.e., warmed-over flavor (WOF)) of the biceps femoris muscle of four Chinese indigenous (i.e., Guangdong small-ear spotted, GSS; hill black, HB; Beijing black, BB; Qingyu, QY) and one hybrid (i.e., Duroc × Landrace × Yorkshire, DLY) pig breeds. Principal component analysis of 20 fatty acids and 30 reheating volatiles showed that five pig breeds could clearly be distinguished from each other. Among the pig breeds studied, GSS showed the lowest WOF contents and odor activity values (OAVs) (1251.87 μg/kg and 1111.64, respectively). Differences in WOF content and OAV among the four other breeds did not significantly differ (P > 0.05). Correlation analysis demonstrated that C16:1, C18:1, and C18:2 may be the key fatty acids of WOF formation. This study provides a new strategy for reducing the WOF of precooked meat products. [Display omitted] • 20 fatty acids and 30 reheating volatiles were identified in different pig breeds. • Five kinds of porks were clearly discriminated by chemometrics analysis. • C16:1, C18:1, and C18:2 exhibited strong positive correlation with WOF indicators. • The WOF in GSS pork was significantly lowest based on content and OAV. [ABSTRACT FROM AUTHOR]