Accurate and affordable detection of rifampicin and isoniazid resistance in Tuberculosis sputum specimens by multiplex PCR-multiple probes melting analysis.

BACKGROUND: Escalating cases of multidrug-resistant tuberculosis (MDR-TB) pose a major challenge to global TB control efforts, necessitating innovative diagnostics to empower decentralized detection of gene mutations associated with resistance to rifampicin (RIF) and isoniazid (INH) in Mycobacterium tuberculosis (M. tuberculosis) in resource-constrained settings. METHODS: Combining multiplex fluorescent PCR and Multiple Probes Melting Analysis, we identified mutations in the rpoB, katG, ahpC and inhA genes from sputum specimens. We first constructed a reference plasmid library comprising 40 prevalent mutations in the target genes' resistance determining regions and promoters, serving as positive controls. Our assay utilizes a four-tube asymmetric PCR method with specifically designed molecular beacon probes, enabling simultaneous detection of all 40 mutations. We evaluated the assay's effectiveness using DNA isolated from 50 clinically confirmed M. tuberculosis sputum specimens, comparing our results with those obtained from Sanger sequencing and retrospective validation involving bacteriological culture and phenotypic drug susceptibility testing (pDST). We also included the commercial Xpert MTB/RIF assay for accuracy comparison. RESULTS: Our data demonstrated remarkable sensitivity in detecting resistance to RIF and INH, achieving values of 93.33% and 95.24%, respectively, with a specificity of 100%. The concordance between our assay and pDST was 98.00%. Furthermore, the accuracy of our assay was comparable to both Sanger sequencing and the Xpert assay. Importantly, our assay boasts a 4.2-h turnaround time and costs only $10 per test, making it an optimal choice for peripheral healthcare settings. CONCLUSION: These findings highlight our assay's potential as a promising tool for rapidly, accurately, and affordably detecting MDR-TB.

Clinical characteristics and microbiological tests analysis of 18 patients with Talaromyces marneffei infection / 中国热带医学

@#Abstract:Objective　To investigate the clinical characteristics and early diagnostic methods of patients with Talaromyces marneffei infection, so as to reduce the mortality of patients. Methods The clinical characteristics and microbiological analysis data including fungal culture, smear examination and mass spectrometry were collected from 18 patients with Talaromyces marneffei infection in the Department of Respiratory Medicine, Department of Tuberculosis, and Department of Critical Respiratory Medicine in Fuzhou Pulmonary Hospital from January 2017 to December 2021, and descriptive analysis was conducted. Results　All the 18 patients were confirmed to be infected with Talaromyces marneffei by conventional culture and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS). The main infection sites of 18 patients with Talaromyces marneffei infection were lungs and lymph nodes, and the patients were accompanied by clinical manifestations such as cough, sputum and fever. The imaging features such as patchy shadows, mediastinal lymph node shadows and nodular shadows were common. Microbiological testing showed a statistically significant difference between smear and culture with a higher positive culture rate (χ2=13.74, P<0.05). The positive rate of blood culture in microbiological test was 60.0% (9/15), the positive rate of bronchial lavage fluid culture was 26.7% (4/15), the positive rate of sputum culture was 5.6% (1/18), one case each of pus, bone marrow, pleural fluid and cerebrospinal fluid was positive for culture and the other cases were negative, one case of sputum and one case of pus were positive for smear and the rest were negative. Colony characteristics showed that the colony morphology was mycelial phase at 25 ℃, producing red pigment, and the branching pattern of the penicillus was seen microscopically as monoverticillate or biverticillate; At 35 ℃, the yeast phase appeared at the initial stage, and then the mycelium phase changed after 5-6 days; the yeast phase was observed at 37 ℃, and yeast-like cells were seen under the microscope. All 18 patients with Talaromyces marneffei infection got better after using antifungal drugs. Compared with non-HIV patients with Talaromyces marneffei infection, leukopenia and anemia were common in HIV patients with Talaromyces marneffei infection, and the differences were statistically significant (P<0.05). 　Conclusions The infection of Talaromyces marneffei can be divided into localized type and disseminated type, which usually invade the lungs, skin, lymph nodes and other places. The main manifestations of patients are fever, cough, phlegm and other atypical symptoms. At present, the diagnosis of Talaromyces marneffei infection is mostly based on the fungal culture test, and the application of MALDI-TOF MS method can effectively shorten the diagnosis time of Talaromycosis marneffei. Clinical characteristics combined with microbiological analysis provide an objective basis for early diagnosis of patients with Talaromyces marneffei infection, and timely use of antifungal therapy can improve the prognosis of patients.

Prevalence, risk and genetic characteristics of drug-resistant tuberculosis in a tertiary care tuberculosis hospital in China.

OBJECTIVES: To explore the prevalence, risk and genetic characteristics of drug-resistant tuberculosis (TB) from a tertiary care TB hospital in China. PATIENTS AND METHODS: We carried out a retrospective study including isolates from 189 patients with pulmonary TB at Fuzhou Pulmonary Hospital. All isolates from these patients were subjected to drug susceptibility testing and genotyping. For drug-resistant isolates, DNA sequencing was used to investigate mutations in 12 loci, including katG, inhA, oxyR-ahpC, rpoB, rpsL, rrs 1 (nucleotides 388-1084 of rrs), embB, tlyA, eis, rrs 2 (nucleotides 1158-1674 of rrs), gyrA and gyrB. RESULTS: Among 189 isolates, 28.6% were resistant to at least one of the seven anti-TB drugs, including isoniazid (INH), rifampin (RIF), streptomycin (STR), ethambutol (EMB), capreomycin (CAP), kanzmycin (KAN) and ofloxacin (OFX). The proportion of multidrug-resistant TB and extensively drug-resistant TB isolates was 9.5% and 1.1%, respectively. Patients in rural areas as well as previously treated patients showed a significantly increased risk of developing drug resistance. In addition, among these isolates, 111 (58.7%) were Beijing genotype strains, 84 (75.7%) of which belonged to modern Beijing sublineage. There was no association between genotype and drug resistance. The most common mutations were katG315, rpo B531 rpsL43, embB306, rrs1401 and gyrA94. CONCLUSION: These findings provided additional information of drug-resistant TB in China. Previously treated patients and patients in rural areas should receive greater attention owing to their higher risk of developing drug resistance.

Immunological Evaluation of a Novel Mycobacterium tuberculosis Antigen Rv0674.

OBJECTIVE: This study aimed to characterize the diagnostic and vaccine potential of a novel Mycobacterium tuberculosis antigen Rv0674. METHODS: To evaluate the diagnostic potential and antigenicity of Rv0674, IgG was evaluated using ELISA and interferon (IFN)-γ was done by using ELISpot assay among TB patients and healthy donors. For immunogenicity evaluation, BALB/c mice were immunized with Rv0674. Cytokine production was determined by cytokine release assay using an ELISA kit, and the antibodies were tested using ELISA. RESULTS: The results of serum Elisa tests showed that Rv0674 specific immunoglobulin G (IgG) response was higher in TB patients than negative controls. And Rv0674 had good performance in serological test with sensitivity and specificity of 77.1% and 81.1%, respectively. While it shows poor sensitivity and specificity of 26.23% and 79.69% for IFN-γ tests. In BALB/c mice, Rv0674 adjuvant by DDA/Poly I:C could also induce a high level of IFN-γ, interleukin-2 and interleukin-6 as well as a high IgG titer in both high- and low-dose groups indicating that Rv0674 is essential in humoral and cellular immunity. Moreover, the cytokine profile and IgG isotype characterized Rv0674 as a Th1/Th2-mixed-type protective immunity with the predominance of Th1 cytokines. CONCLUSION: Rv0674 may be a good potential candidate for the development of TB serological diagnosis and a new TB vaccine.

Down-expression of circulating micro ribonucleic acid (miRNA)-148/152 family in plasma samples of non-small cell lung cancer patients.

AIMS: Circulating extracellular micro ribonucleic acids (miRNAs) are considered as potential biomarkers for malignancy detection and diagnosis. The aim of this study was to determine whether circulating miRNA-148/152 family (miR-148a, miR-148b, and miR-152) expression in plasma could be used as potential biomarkers for non-small cell lung cancer (NSCLC) patients and healthy individuals. SUBJECTS AND METHODS: The levels of miRNA-148/152 family were detected by TaqMan quantitative polymerase chain reaction (qPCR) assay in plasma of 20 NSCLC patients and 10 healthy individuals. The miRNA expression level of each sample was normalized to that of miR-16 and expressed as relative expression (2-ΔΔCt). RESULTS: The circulating level of all three members of miRNA-148/152 family were significantly lower in plasma samples of NSCLC patients compared with those of healthy controls (P = 0.007, P = 0.003, and P = 0.000, respectively). The expression levels of miR-148a, miR-148b, and miR-152 in the late-stage NSCLC group were all lower than the early-stage NSCLC group (all P < 0.05). CONCLUSIONS: The present study suggests that the expression levels of miR-148/152 family in plasma might be useful biomarkers for NSCLC patients samples in the early diagnosis of NSCLC and monitoring of tumour development.

Stiffness of various pin configurations for pediatric supracondylar humeral fracture: a systematic review on biomechanical studies.

To compare the biomechanical stability of various pin configurations for pediatric supracondylar humeral fractures under varus, internal rotation, and extension conditions. After electronic retrieval, 11 biomechanical studies were included. Stiffness values of pin configurations under different loading conditions were extracted and pooled. There were no statistically significant differences between two cross pins and two divergent lateral pins on the basis of the 'Hamdi method' (P=0.249-0.737). An additional pin did not strengthen two-pin construct (P=0.124-0.367), but better stabilized fractures with medial comminution (P<0.01). Isolated lateral pins are preferable because of a better balance of a lower risk of nerve injury and comparable fixation strength. Limitations such as differences in experimental setup among recruited studies and small sample size may compromise the methodologic power of this study.

Novel species including Mycobacterium fukienense sp. is found from tuberculosis patients in Fujian Province, China, using phylogenetic analysis of Mycobacterium chelonae/abscessus complex.

OBJECTIVE: To identify the novel species 'Mycobacterium fukienense' sp. nov of Mycobacterium chelonae/abscessus complex from tuberculosis patients in Fujian Province, China. METHODS: Five of 27 clinical Mycobacterium isolates (Cls) were previously identified as M. chelonae/abscessus complex by sequencing the hsp65, rpoB, 16S-23S rRNA internal transcribed spacer region (its), recA and sodA house-keeping genes commonly used to describe the molecular characteristics of Mycobacterium. Clinical Mycobacterium isolates were classified according to the gene sequence using a clustering analysis program. Sequence similarity within clusters and diversity between clusters were analyzed. RESULTS: The 5 isolates were identified with distinct sequences exhibiting 99.8% homology in the hsp65 gene. However, a complete lack of homology was observed among the sequences of the rpoB, 16S-23S rRNA internal transcribed spacer region (its), sodA, and recA genes as compared with the M. abscessus. Furthermore, no match for rpoB, sodA, and recA genes was identified among the published sequences. CONCLUSION: The novel species, Mycobacterium fukienense, is identified from tuberculosis patients in Fujian Province, China, which does not belong to any existing subspecies of M. chelonea/abscessus complex.

Multicenter research on the BACTEC MGIT 960 system for the second-line drugs susceptibility testing of Mycobacterium tuberculosis in China.

The reliability of the BACTEC MGIT 960 system for the second-line drugs (capreomycin [CPM], kanamycin [KAN], ofloxacin [OFX] and ethionamide [ETH]) susceptibility testing (DST) of Mycobacterium tuberculosis (M. tuberculosis) was compared to that of traditional Lowenstein-Jensen (L-J) proportion method (PM) among four different sites in China. After resolution of discrepant results by retesting the strains using both methods in the National Reference Laboratory of tuberculosis, the overall concordance values between the 2 systems were 99.7% (kappa value: 0.97) for CPM, 99.7% (kappa value: 0.97) for KAN, 100.0% (kappa value: 1.00) for OFX, and 98.6% (kappa value: 0.95) for ETH. The average turnaround time with BACTEC MGIT 960 system among four sites was 8.9 ± 1.7 days, significantly shorter than 28 days with the traditional L-J PM. Therefore, the BACTEC MGIT 960 system is a reliable and rapid method for the second-line drug susceptibility testing of tuberculosis in China. Notably, a stricter quality control program should be routinely carried out when clinical laboratories perform the second-line DST with BACTEC MGIT 960 system.

[Quantitative evaluation of soil hyperspectra denoising with different filters].

The noise distribution of soil hyperspectra measured by ASD FieldSpec Pro FR was described, and then the quantitative evaluation of spectral denoising with six filters was compared. From the interpretation of soil hyperspectra, the continuum removed, first-order differential and high frequency curves, the UV/VNIR (350-1 050 nm) exhibit hardly noise except the coverage of 40 nm in the beginning 350 nm. However, the SWIR (1 000-2 500 nm) shows different noise distribution. Especially, the latter half of SWIR 2(1 800-2 500 nm) showed more noise, and the intersection spectrum of three spectrometers has more noise than the neighbor spectrum. Six filters were chosen for spectral denoising. The smoothing indexes (SI), horizontal feature reservation index (HFRI) and vertical feature reservation index (VFRI) were designed for evaluating the denoising performance of these filters. The comparison of their indexes shows that WD and MA filters are the optimal choice to filter the noise, in terms of balancing the contradiction between the smoothing and feature reservation ability. Furthermore the first-order differential data of 66 denoising soil spectra by 6 filters were respectively used as the input of the same PLSR model to predict the sand content. The different prediction accuracies caused by the different filters show that compared to the feature reservation ability, the filter's smoothing ability is the principal factor to influence the accuracy. The study can benefit the spectral preprocessing and analyzing, and also provide the scientific foundation for the related spectroscopy applications.

[Study on the characteristics of mutation on Mycobacterium tuberculosis rifampicin-resistance gene].

OBJECTIVE: To elucidate the characters of rpoB mutation in rifampin-resistant clinical isolates of Mycobacterium tuberculosis. METHODS: 286 bp DNA fragment of rpoB gene including 81 bp code region (rifampin resistance deteremination region, RRDR) was analyzed by PCR-single-strand conformation polymorphism(SSCP). The 286 bp DNA fragment of each strain which had been proved to have mutation by PCR-SSCP was then sequenced. 110 strains of M. tuberculosis, including 73 rifampin-resistant strains, 11 rifampin-susceptible drug-resistant strains and 26 drug-susceptible strains were studied. RESULTS: 47 rifampin-resistant strains were detected to have mutations by PCR-SSCP method. 76.6% rifampin-resistant strains showed that rpoB gene was carrying single point mutation analyzed by direct sequencing technique, which mainly located at 531-Ser (61.1%) and 526-His (25.0%). The combined mutation rate was 23.4%. In addition, 2 rifampin-susceptible drug-resistant strains and 1 drug-susceptible strain were mutated, detected by PCR-SSCP method. Sequencing results showed that the mutations located at 511-Leu, 526-His and 535-Pro. CONCLUSION: Mutations in the 81 bp RRDR of rpoB were the main reasons of M. tuberculosis resistant to rifampin. 531-Ser and 526-His were the most common positions of mutations.

Detection of coastal saline land uses with multi-temporal landsat images in Shangyu City, china.

Many coastal regions in China are confronted with pressing problems of scarce land resources and heavy population. Over the past 30 years, considerable parts of coastal tidelands have been enclosed and reclaimed for agricultural land uses. To assess, plan, and implement large-scale reclamation programs, up-to-date and reliable information concerning the nature, areal extent, and physical and chemical characteristics of coastal saline lands is essential. This paper reports a remote sensing approach to detecting coastal saline land uses in Shangyu City, China, by using multi-temporal Landsat images. First, with the aid of resolution-sharpened Landsat-7 ETM+ images and their enhanced linear features, a visual interpretation is applied to extract individual dikes. Based on time series images and local government records, a spatial zoning procedure is then used to define six sub-zones with different historical years of reclamation. It shows that a total of 15,668 ha of coastal saline lands were enclosed and reclaimed from 1969 to 1996. Second, a modified land-use classification system for the study area is prescribed, and both unsupervised and supervised classifiers are performed for land-use classifications of grouped sub-zones. Information obtained from the spatial zoning, Tasseled Cap transformation and Normalized Difference Vegetation Index, is also utilized to facilitate the supervised classification process. Finally, a detailed land-use map is produced, with an overall classification accuracy of 77.8%. Results show that dominant agricultural land uses of sub-zones are changed with historical reclamation years, from saline lands with wildgrass (very recently reclaimed) to aqua-farm ponds, to cotton fields, and to paddy fields and orchards (very early reclaimed). This transform process is primarily affected by soil salinities, and according to a soil survey an electrical conductivity of saturation extract decreased from 7.3 ds/m in the saline land reclaimed in 1996 to below 2 ds/m in the land reclaimed before 1969. The study concludes that multi-temporal remotely sensed images are important and effective data sources for monitoring the rapid changes of coastal land uses.