A rapid and simple resazurin assay to detect minimum inhibitory concentrations of first-line drugs for Mycobacterium tuberculosis isolated from cerebrospinal fluid

Crystal violet decolorization assay: a simplified colorimetric test for the rapid detection of multidrug-resistant Mycobacterium tuberculosis isolates

The increased prevalence of multi-drug resistant M. tuberculosis is quite possibly the direst and most difficult task for the early diagnosis and treatment. A rapid, reliable, and inexpensive diagnostic method is the need of the hour. The current study on crystal violet decolorization assay explores the possibility to develop a rapid and simple detection method to detect multi-drug-resistant tuberculosis isolates by comparing the results with the traditional liquid culture drug susceptibility testing method based on their sensitivity, specificity, positive predictive value, and negative predictive value. 70 isolates were used for the study and were detected as multi-drug resistant, mono drug-resistant, and sensitive by using crystal violet decolourization assay and further compared with the results of DST and using H37Rv as the standard control strain. The sensitivity, specificity, positive predictive value, and negative predictive value of crystal violet decolorization assay (Rifampicin: 100%, 94.60%, 100% and 82.40%; isoniazid: 100%, 94.10%, 100%, 86.40%) are calculated and the percentage were compared with the conventional liquid culture drug susceptibility testing for M. tuberculosis using rifampicin and isoniazid. Crystal violet decolourization assay is rapid, reproducible, and doesn't require any highly experienced personal or sophisticated laboratory instruments for interpretation. This assay is found to be nearly as reliable as conventional liquid culture drug susceptibility testing and may thus be of great help in phenotypic confirmation of multi-drug resistant tuberculosis by providing results more rapidly.

High-dose rifampicin for the treatment of tuberculous meningitis: a meta-analysis of randomized controlled trials

WHAT IS KNOWN AND OBJECTIVE

Tuberculous meningitis (TBM) is one of the most serious types of extrapulmonary tuberculosis and has caused distress to human. Effective treatment is particularly important. The aim of this meta-analysis is to compare the efficacy of high-dose and standard-dose rifampicin.

METHODS

Databases including PubMed, Web of Science, Embase, Scopus and the Cochrane Library databases were electronically searched to identify randomized controlled trials that reported high-dose rifampicin in treatment of patients with TBM. The retrieval time is limited from inception to June 2021. Two reviewers independently screened literature, extracted data and assessed risk bias of included studies. Meta-analysis was performed by using STATA 12.0 software.

RESULTS AND DISCUSSION

A total of 12 studies involving 1596 patients were included. The meta-analysis results showed no significant differences in 6-month mortality, 9-month mortality, Grade I-II AE, Grade III-V AE, hepatotoxicity, hepatotoxicity Grade I-II and cardiologic events between high-dose rifampicin (or high-dose rifampicin plus moxifloxacin or levofloxacin) and standard-dose groups. The log(C_max ) (WMD 0.69, 95%CI 0.59-0.79, p 0.001) and log(AUC_0-24h ) (WMD 0.79, 95%CI 0.71-0.88, p 0.001) were higher with high-dose rifampicin. Subgroup analysis revealed the rise of log(C_max ) in high-dose rifampicin orally was consistent with intravenous administration compared with the control (WMD 0.69, 95%CI 0.66-0.73, p 0.001).

WHAT IS NEW AND CONCLUSION

High-dose rifampicin was not a protective factor for 6-month mortality, despite increased plasma C_max and AUC_0-24h . However, the above conclusions are still required to be verified through more RCTs due to the limited quantity of included studies.

Progressive Applications of Hyperbranched Polymer Based on Diarylamine: Antimicrobial, Anti-Biofilm and Anti-Aerobic Corrosion

New generations of hyperbranched aramids were synthesized from diarylamine and methyl acrylate using an AB₂ monomer approach in a straightforward one-pot preparation. The chemical structure of hyperbranched Phenylenediamine/Methyl Acrylate HB(PDMA was confirmed by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (¹HNMR) spectroscopy. In addition, the particle’s size and distribution were recorded using Dynamic Light Scattering (DLS). Moreover, the synthesized HB(PDMA)s displayed broad-spectrum antimicrobial activities against Gram-positive and Gram-negative bacteria as well as yeast strains and anti-biofilm activity where the highest activity was attributed to HB(PDMA)G₄ at the lowest Minimum Inhibitory, Minimum Bactericidal, and Fungicidal Concentrations (MIC, MBC, and MFC, respectively). Furthermore, the HB(PDMA)s expressed anti-bacterial activity against isolated Pseudomonas sp. (R301) at a salinity of 35,000 ppm (NaCl). In addition, they revealed different corrosion inhibition efficiencies at the cultivated medium salinity at the estimated minimum bactericidal concentrations. The highest metal corrosion inhibition efficiencies were 59.5 and 94.3% for HB(PDMA)G₄ at the Minimum Bactericidal Concentrations (MBCs) and two times Minimum Bactericidal Concentrations (2XMBCs), respectively, in comparison to both negative and positive controls.

Enhancement of A Cationic Surfactant by Capping Nanoparticles: Synthesis, Characterization and Multiple Applications

There is scarce information on cationic surfactants’ biocidal and corrosion inhbibition effects on Slime-Forming Bacteria (SFB) isolated from oil field formation water. Therefore, this work focused on the the synthesis of a cationic surfactant (CS) to increase its features by capping different metal nanoparticles (zinc, ZnNPs-C-CS; manganese, MnNPs-C-CS and tin, SnNPs-C-CS) and used them as biocides and corrosion inhibitors. The cationic surfactant was synthesized and characterized by Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. Afterwards, different nanoparticles were synthesized, characterized, and exploited to cap by the CS. The CS and the different nanoparticles capped by the CS were tested for their antimicrobial susceptibility against standard bacterial and yeast strains. The synthesized compounds were further evaluated as anti-biofilms agents against positively-developed bacterial biofilms. Moreover, the CS and the ZnNPs-C-CS, MnNPs-C-CS, and SnNPs-C-CS were assessed as potential biocides against SFB, particularly Pseudomonas sp. (isolated from contaminated formation water), and as corrosion inhibitors against cultivated salinity. The results revealed the great effect of the different CS-capped NPs as broad-spectrum antimicrobial and anti-biofilm agents at lower Minimum Inhibitory Concentrations (MICs), Minimum Bactericidal Concentrations (MBCs), Minimum Fungicidal Concentrations (MFCs) and Minimum Biofilm Inhibitory Concentrations (MBICs), and the activities were reported in order of SnNPs-C-CS > MnNPs-C-CS > ZnNPs-C-CS > CS. Furthermore, the ZnNPs-C-CS, MnNPs-C-CS, and SnNPs-C-CS demonstrated biocidal and corrosion inhibition effects against Pseudomonas sp. at a salinity of 3.5% NaCl, with metal corrosion inhibition efficiencies of 88.6, 94.0 and 96.9%, in comparison to a CS efficiency of 85.7%. In conclusion, the present work provides a newly synthesized cationic surfactant and has enhanced its antimicrobial and its metal corrosion inhibition effects by capping different nanoparticles, and it has been successfully applied against slime-forming bacteria at a salinity of 3.5% NaCl.

Age-associated changes in the response of tendon explants to stress deprivation is sex-dependent

Purpose of the Study: The incidence of tendon injuries increases dramatically with age, which presents a major clinical burden. While previous studies have sought to identify age-related changes in extracellular matrix structure and function, few have been able to explain fully why aged tissues are more prone to degeneration and injury. In addition, recent studies have also demonstrated that age-related processes in humans may be sex-dependent, which could be responsible for muddled conclusions in changes with age. In this study, we investigate short-term responses through an ex vivo explant culture model of stress deprivation that specifically questions how age and sex differentially affect the ability of tendons to respond to altered mechanical stimulus.Materials and Methods: We subjected murine flexor explants from young (4 months of age) and aged (22-24 months of age) male and female mice to stress-deprived culture conditions for up to 1 week and investigated changes in viability, cell metabolism and proliferation, matrix biosynthesis and composition, gene expression, and inflammatory responses throughout the culture period.Results and Conclusions: We found that aging did have a significant influence on the response to stress deprivation, demonstrating that aged explants have a less robust response overall with reduced metabolic activity, viability, proliferation, and biosynthesis. However, age-related changes appeared to be sex-dependent. Together, this work demonstrates that the aging process and the subsequent effect of age on the ability of tendons to respond to stress-deprivation are inherently different based on sex, where male explants favor increased activity, apoptosis, and matrix remodeling while female explants favor reduced activity and tissue preservation.