[Evaluation of the efficacy of urine-based lipoarabinomannan antigen test in the diagnosis of pulmonary tuberculosis].

Objective: To analyze the diagnostic efficacy of urinary lipoarabinomannan (LAM) antigen detection method in tuberculosis patients, and to provide an experimental basis for the clinical application of urinary LAM kit in China. Methods: From March to May 2023, 228 patients with lung diseases [134 male, 94 female, age 20-82 (44.8±16.7) years] were prospectively collected in Beijing Chest Hospital, Capital Medical University, including 143 pulmonary tuberculosis patients and 85 non-tuberculosis patients. Urine and sputum samples from patients were collected for traditional etiological detection and urinary LAM antigen detection. The screening results of each positive detection combination were analyzed, and the difference analysis and regression analysis were performed. Results: The detection sensitivity and specificity of the urinary LAM kit were 46.2% (95%CI: 37.9%-54.7%) and 96.5% (95%CI: 89.3%-99.1%), respectively, with an overall coincidence rate of 64.9%. The detection rate of LAM antigen detection and GeneXpert MTB/RIF (Xpert) combined (60.8%, 87/143) was significantly higher than that of Xpert alone (49.7%, 71/143), and the difference was statistically significant (P<0.05). The results of risk factor analysis showed that the risk of negative urinary LAM antigen test results increased significantly as the bacterial load decreased. Conclusions: Urine LAM antigen detection method has a high specificity and can be combined with traditional methods to effectively improve the detection rate. Urinary LAM antigen detection method still has limitations, such as the influence of bacterial load and the inability to distinguish nontuberculosis mycobacteria samples, which needs further experimental verification.

[Effects of four efflux pump inhibitors on the activities of clarithromycin against Mycobacterium abscessus].

Objective: To detect the effects of four efflux pump inhibitors on the minimum inhibitory concentration of clarithromycin (CLA) against Mycobacterium abscessus (M. abscessus) in vitro, and to explore the role of efflux pump in CLA resistance of M. abscessus. Methods: Four frequently-used efflux pump inhibitors (Carbonyl Cyanide 3-chlorophenylhydrazone, CCCP, N, N'-dicyclohexylcarbodiimide, DCC, Verapamil, VP, Reserpine, RSP) were evaluated in this study. The minimum inhibitory concentration (MIC) values of clarithromycin against M. abscessus reference strain and 60 clinical strains with or without efflux pump inhibitors were detected by Alamar Blue method. Sequence analysis of erm(41) and rrl genes known to be associated with CLA resistance in M. abscessus was performed to analyze the correlation between the effect of efflux pump inhibitors on MIC and mutation of resistance-related genes. Results: CCCP, DCC, VP and RSP could reduce the MIC of M. abscessus to CLA, and the effect of RSP was weaker than the other three efflux pump inhibitors. Among the sixty M. abscessus clinical strains, ten strains were resistant to clarithromycin, seven of which had rrl gene mutation. The CLA resistance rate of smooth phenotype isolates was higher than that of rough phenotype isolates. At 3 day of clarithromycin incubation, the MICs of resistant strains were all reduced by efflux pump inhibitors. Compared with the strains with rrl gene mutation, efflux pump inhibitors had a greater effect on the strains without rrl gene mutation. At 14 day of clarithromycin incubation, 83% of M. abscessus subsp. abscessus, were induced to be resistant, and all of them were T28 sequence type of erm(41). With the occurrence of induced drug resistance, the effect of efflux pump inhibitor on CLA MIC decreased. Efflux pump inhibitors had no statistically significant diffence in the effect of effcux pump inhibitors on CLA MIC levels in different phenotypes of isolates. Conclusions: Efflux pump is involved in the resistance process of M. abscessus to CLA. Efflux pump inhibitors reduce the drug resistance to clarithromycin against M. abscessus in different degrees. The use of efflux pump inhibitors may provide a new way to alleviate the drug resistance of M. abscessus.

[Analysis of resistance to clofazimine in tuberculosis patients].

Objective: To analyze the drug resistance of tuberculosis patients to clofazimine. Methods: Retrospective analysis was conducted on the case data of 1 770 tuberculosis patients in Department of tuberculosis, Beijing Chest Hospital affiliated to Capital Medical University from January 2015 to June 2018, including 1 225 males and 545 females, aged 8-92 (43.2±15.2) years old. Drug sensitivity tests using proportion method (hereinafter referred to as drug susceptibility test) for TB strains anti-tb drug resistance test. Using χ2 test or Fisher's exact test. Results: 1 770 cases of tuberculosis patients, 1 713 cases of patients with clofazimine sensitive, of 57 patients with drug resistance, and resistant rate was 3.2% (57/1 770), including patients with recurrent clofazimine, significantly higher than the initial percentages of patients [5.8% (38/656), 1.7% (19/1 114), χ²= 22.129, P = 0.000, P<0.01]; The drug resistance rates of poly-resistant, multi-drug resistant and extensively resistant patients to clofazimine were 1.0% (17/1 770), 1.2% (21/1 770) and 1.1% (19/1 770), respectively. Has a history of hospitalization of clofazimine resistance of multidrug-resistant and extensively drug-resistant patients resistant rate 2.4% (14/594), 2.7% (16/594), respectively, higher than 0.6% (7/1 176) with no history of hospitalized patients, 0.3% (3/1 176), the differences were statistically significant (χ²=10.447,22.099,P=0.001,<0.001). Conclusion: Clofazimine has a low resistance rate, which can improve the treatment success rate of patients with drug-resistant tuberculosis and has important value.

[Analysis on related factors of myocardial fibrosis in patients with hypertrophic cardiomyopathy].

Objective: To investigate the related factors of myocardial fibrosis in patients with hypertrophic cardiomyopathy. Methods: Patients with hypertrophic cardiomyopathy, hospitalized in the First People's Hospital of Yunnan Province from January 2016 to May 2020, were included in this cross-sectional study. Patients were divided into delayed enhancement positive group (fibrosis group) and non-delayed enhancement group (non-fibrosis group). According to the maximum left ventricular end diastolic wall thickness (LVMWT), patients in the fibrosis group was further divided into mild hypertrophy group, moderate hypertrophy group and severe hypertrophy group. The baseline clinical data of patients were collected by medical record management system. All enrolled patients underwent cardiac magnetic resonance imaging (CMR). The presence and location of myocardial fibrosis were identified by CMR gadolinium contrast delayed enhancement (LGE). The range of LGE (LGE%) was calculated by visual analysis. The levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) in peripheral blood were measured. Results: A total of 48 patients ( age (46.4±14.3) years, 42 (87.5%) males) were enrolled. There were 34 LGE positive cases (fibrosis group) and 14 LGE negative cases (non-fibrosis group). Compared with non-fibrosis group, patients in fibrosis group were younger (P=0.038) and prevalence of NYHA grade Ⅲ/Ⅳ was higher (P=0.00). Compared with non-fibrosis group, patients in fibrosis group had thicker LVMWT (P= 0.008), higher left ventricular mass index(LVMI) (P=0.001), higher left ventricular end diastolic volume (LVEDV) (P=0.043), lower left ventricular ejection fraction (LVEF) and cardiac index (CI) (all P <0.05). The levels of NT-proBNP and cTnI were significantly higher in fibrosis group than in non-fibrosis group (2 760.5 (1 503.4, 3 783.6) ng / L vs. 861.3 (552.2, 1 092.8) ng / L, P=0.002; 0.970 (0.448, 1.684)µg / L vs. 0.147 (0.033, 0.251)µg / L, P=0.041).In fibrosis group, there were 15 cases of mild hypertrophy (mild hypertrophy group), 10 cases of moderate hypertrophy (moderate hypertrophy group), and 9 cases of severe hypertrophy (severe hypertrophy group). The LGE% and NT-proBNP and cTnI increased in proportion with increasing myocardial hypertrophy (P<0.05). LGE% was negatively correlated with age (r=-0.618, P=0.011), and positively correlated with NT-proBNP and cTnI levels (r=0.271, P=0.010; r=0.111,P=0.013, respectively), and positively correlated with LVEDV, LVMWT and LVMI (r=0.438, P=0.09; r=0.735, P=0.001; r=0.532, P=0.034, respectively). Conclusions: In patients with hypertrophic cardiomyopathy, the extent of myocardial fibrosis increases with the increase of myocardial hypertrophy. Myocardial fibrosis is negatively correlated with age, and positively correlated with NT-proBNP and cTnI, as well as LVEDV, LVMWT and LVMI in this patient cohort.

[Incremental cost-effectiveness of the second Xpert MTB/RIF assay for detection of Mycobacterium tuberculosis].

Objective: To study the incremental cost-effectiveness of the second Xpert assay in detection of Mycobacterium tuberculosis (Mtb) and rifampicin (RIF) resistance. Methods: We continuously collected 2 896 specimens from suspected tuberculosis patients who had undergone 2 Xpert tests in a week from March 2015 to March 2018, including 2 402 suspected tuberculosis patients with 1 523 males and 879 females, with an average age of 50 years. Among them, 2 144 specimens of sputum and 258 cases of bronchoalveolar lavage fluid were collected. We also enrolled 494 patients with suspected extrapulmonary tuberculosis, 318 males and 176 females, with an average age of 42 years. Among them, 157 pleural effusion specimens, 106 cerebrospinal fluid specimens, 34 urine specimens and 197 pus specimens were collected. All specimens were subjected to two Xpert tests, smear microscopy, liquid rapid culture (BACTEC MGIT 960), and positively cultured bacteria were tested for drug susceptibility. Results: Among the 2 896 specimens from suspected tuberculosis patients, either one of the two Xpert test results was positive (including both tests were positive, the same below) in 1 639 patients, and 1 502 (91.6%) were positive in the first Xpert tests. The additional 137 (8.4%) test results were positive in the second tests. According to the smear test results, all specimens were divided into the smear negative group and the smear positive group. The second Xpert test was significantly higher than the smear-positive group (14.86%, 3.2%, P<0.001), and the extrapulmonary tuberculosis group was higher than the tuberculosis group (11.2%, 8.0%, P=0.12).Of the susceptibility test results, a total of 371 were rifampicin-resistant specimens. The first Xpert detected 91.4% (339/371), and the second Xpert detected the additional 8.1% (30/371).The cost increase of the second test was very significant. Tests were calculated at 650 yuan per time, the tuberculosis group was 1 184 yuan and 13 696 yuan(P<0.001); the extrapulmonary tuberculosis group was 1 755 yuan and 13 961 yuan(P<0.001). In the test of specimens of tuberculosis and extrapulmonary tuberculosis, the smear-negative specimen cost increase of the second Xpert test was lower than that of the smear-positive specimen. Conclusion: The second xpert test showed significant value-added cost-effectiveness in the diagnosis of tuberculosis.

[Evaluation of a high-intensity fluorescent fluorophage method for diagnosis of drug-resistance in tuberculosis].

Objective: To evaluate the high-intensity green fluorescent protein fluorophage Φ(2)GFP10 method for drug susceptibility testing of tuberculosis for isoniazid(INH), rifampin(RIF), and streptomycin(SM). Methods: A total of 128 clinical M. tuberculosis strains were isolated from patients with suspected drug-resistant tuberculosis visiting Beijing Chest Hospital (Beijing, China) from April to June 2014.All of the isolates were tested by the phage assay, while conventional drug susceptibility tests were performing on Lwenstein-Jensen culture medium as reference. Results: The sensitivities of Φ(2)GFP10 assay for INH, RIF, and SM resistance detection were 100.0%, 98.1%(53/54), and 92.6%(50/54), respectively, while their specificities were 84.8%(56/66), 91.9%(68/74), and 91.9%(68/74), respectively. The agreement between the phage assay and the conventional assay for detecting INH, RIF, and SM resistance was 0.92, 0.95 and 0.92, respectively. The Φ(2) GFP10-phage assay could be done within 2 days for RIF and SM, and 3 days for INH. Conclusions: The Φ(2)GFP10-phage method for drug susceptibility test is very sensitive and specific. The method has the potential to be a valuable, rapid and economical screening method for detecting drug-resistant tuberculosis.

Evidence for a new allele at the SERCA1 locus affecting pork meat quality in part through the imbalance of Ca2+ homeostasis.

Sarcoendoplasmic reticulum Ca2+-ATPase 1 (SERCA1) as a Ca2+ release channel plays a key role in the relaxation of skeletal muscle through pumping cytosolic Ca2+ into the SR (sarcoplasmic reticulum). In this study, a novel single nucleotide polymorphism (SNP) in exon 8 (C > T) was detected by tetra-primer ARMS-PCR and the tissue expression pattern of SERCA1 was analyzed in eleven tissues. A model of primary skeletal muscle cells in vitro exposed to dexamethasone (DEX, a synthetic corticosteroid) was also employed to determine whether stress hormones cause an increase in intracellular Ca2+ concentration that is associated with alteration in SERCA1 and in turn subsequently affect meat quality. The results showed that the CC genotype has lower content intramuscular fat and higher water than pig carrying the genotype CT and CC. In addition, the additive effects were both significantly (P < 0.05) and allele T seemed to be associate with increase in intramuscular fat, while decrease in water content. Accompanied with previous studies, the high abundance of porcine SERCA1 was found in skeletal muscle tissue. DEX markedly down-regulated the expression of SERCA1, leading to Ca2+ overload. Furthermore, the imbalance of Ca2+ homeostasis up-regulated the transcription level of Calpain1. Taken together, we demonstrated a novel mechanism that the changes in expression of SERCA1 potential disturb the normal Ca2+ channel as well as the balance of Ca2+ homeostasis and which in turn finally activated Ca2+-dependent proteases such as Calpain1 which could affect meat quality.