CD137 expression and signal function drive pleiotropic γδ T-cell effector functions that inhibit intracellular M. tuberculosis growth.

Co-activation signal that induces/sustains pleiotropic effector functions of antigen-specific γδ T cells remains unknown. Here, Mycobacteria tuberculosis (Mtb) tuberculin administration during tuberculosis (TB) skin test resulted in rapid expression of co-activation signal molecules CD137 and CD107a by fast-acting Vγ2Vδ2 T cells in TB-resistant subjects (Resisters), but not patients with active TB. And, anti-CD137 agonistic antibody treatment experiments showed that CD137 signaling enabled Vγ2Vδ2 T cells to produce more effector cytokines and inhibit intracellular Mtb growth in macrophages (Mɸ). Consistently, Mtb antigen (Ag) HMBPP stimulation induced sustainable high-level CD137 expression in fresh and activated Vγ2Vδ2 T cells from uninfected subjects, but not TB patients. CD137+Vγ2Vδ2 T-cell subtype predominantly displayed central memory phenotype and mounted better proliferative responses than CD137-Vγ2Vδ2 T-cells. In response to HMBPP, CD137+Vγ2Vδ2 T-cell subtype rapidly differentiated into greater numbers of pleiotropic effector cells producing anti-Mtb cytokines compared to CD137-Vγ2Vδ2 T subtype, with the non-canonical NF-κB pathway involved. CD137 expression in Vγ2Vδ2 T cells appeared to signal anti-Mtb effector functions leading to intracellular Mtb growth inhibition in Mɸ, and active TB disrupted such CD137-driven anti-Mtb effector functions. CD137+Vγ2Vδ2 T-cells subtype exhibited an epigenetic-driven high-level expression of GM-CSF and de novo production of GM-CSF critical for Vγ2Vδ2 T-cell controlling of Mtb growth in Mϕ. Concurrently, exosomes produced by CD137+Vγ2Vδ2 T cells potently inhibited intracellular mycobacterial growth. Furthermore, adoptive transfer of human CD137+Vγ2Vδ2 T cells to Mtb-infected SCID mice conferred protective immunity against Mtb infection. Thus, our data suggest that CD137 expression/signaling drives pleiotropic γδ T-cell effector functions that inhibit intracellular Mtb growth.

Exploring the potential of Lactocaseibacillus rhamnosus PMC203 in inducing autophagy to reduce the burden of Mycobacterium tuberculosis.

Mycobacterium tuberculosis, a lethal pathogen in human history, causes millions of deaths annually, which demands the development of new concepts of drugs. Considering this fact, earlier research has explored the anti-tuberculosis potential of a probiotic strain, Lactocaseibacillus rhamnosus PMC203, leading to a subsequent focus on the molecular mechanism involved in its effect, particularly on autophagy. In this current study, immunoblotting-based assay exhibited a remarkable expression of autophagy marker LC3-II in the PMC203 treated group compared to an untreated group. A remarkable degradation of p62 was also noticed within treated cells compared to control. Furthermore, the immunofluorescence-based assay showed significant fold change in fluorescence intensity for alexa-647-LC3 and alexa-488-LC3, whereas p62 was degraded noticeably. Moreover, lysosomal biogenesis generation was elevated significantly in terms of LAMP1 and acidic vesicular organelles. As a result, PMC203-induced autophagy played a vital role in reducing M. tuberculosis burden within the macrophages in treated groups compared to untreated group. A colony -forming unit assay also revealed a significant reduction in M. tuberculosis in the treated cells over time. Additionally, the candidate strain significantly upregulated the expression of autophagy induction and lysosomal biogenesis genes. Together, these results could enrich our current knowledge of probiotics-mediated autophagy in tuberculosis and suggest its implications for innovatively managing tuberculosis.

Design, synthesis, biological evaluation study of spirocyclic POM analogues as novel MmpL3 anti-tubercular agent.

We present the development of a phenyl oxazole methyl (POM) core structure with spirocyclic derivatives as part of our efforts to discover innovative anti-tuberculosis agents. Derivatives of spirocyclic POM were synthesized and evaluated for their inhibitory effects on M.tuberculosis (M. tb) H37Rv. Notably, compound 5c displayed potent anti-tubercular activity with MIC value of 0.206 µM in culture broth medium. Furthermore MIC values of compound 5c against DS/MDR/pre-XDR clinical isolates ranged from 0.34 to 0.68 µg/mL, 0.17 to 0.68 µg/mL, and 0.17 to 0.34 µg/mL, respectively. Also, compound 5c with favorable ADME and PK properties was not cytotoxic to THP-1 human cells. Based on the spontaneous mutant generation, we have identified the target of compound 5c to be MmpL3. The computational docking study suggested its plausible binding mode against MmpL3. There is no approved drug targeting this target yet, and the outcomes of the presented research will contribute to the future discovery of novel anti-tuberculosis drugs.

Study on the Anti-Mycobacterium marinum Activity of a Series of Marine-Derived 14-Membered Resorcylic Acid Lactone Derivatives.

With the emergence of drug-resistant strains, the treatment of tuberculosis (TB) is becoming more difficult and there is an urgent need to find new anti-TB drugs. Mycobacterium marinum, as a model organism of Mycobacterium tuberculosis, can be used for the rapid and efficient screening of bioactive compounds. The 14-membered resorcylic acid lactones (RALs) have a wide range of bioactivities such as antibacterial, antifouling and antimalarial activity. In order to further study their bioactivities, we initially constructed a 14-membered RALs library, which contains 16 new derivatives. The anti-M. marinum activity was evaluated in vitro. Derivatives 12, 19, 20 and 22 exhibited promising activity with MIC90 values of 80, 90, 80 and 80 µM, respectively. The preliminary structure-activity relationships showed that the presence of a chlorine atom at C-5 was a key factor to improve activity. Further studies showed that 12 markedly inhibited the survival of M. marinum and significantly reduced the dosage of positive drugs isoniazid and rifampicin when combined with them. These results suggest that 12 is a bioactive compound capable of enhancing the potency of existing positive drugs, and its effective properties make it a very useful leads for future drug development in combating TB resistance.

Biological and Computational Studies of Hydrazone based Transition Metal(II) Complexes.

In the chronicles of human history, infectious diseases played a pivotal role, influencing societies, steering advancements in medicine, and significantly impacting the well-being of people worldwide. Consequently, in the pursuit of identifying effective combating agents for infectious ailments, the Co(II), Ni(II), Cu(II), Zn(II) complexes of N'-(4-nitrobenzylidene)benzohydrazide were synthesized in the current investigation. Numerous spectral and physical analysis were conducted to characterize the compounds which revealed octahedral stereochemistry of complexes. The anti-tuberculosis, anti-inflammatory, antibacterial and antifungal investigations demonstrated that the compounds (1-5) have significant efficacy for these infectious ailments. The [Zn(L)2(H2O)2] complex (5) has comparable TB inhibition potency to streptomycin as shown by MIC value of 0.0196 ± 0.0003 µmol/mL. Additionally, the anti-inflammatory, antibacterial and antifungal studies also revealed the comparable inhibiting property of (5) to standard drugs with significant IC50 (07.49 ± 0.08 µM) and MIC (0.0098 µmol/mL) values. Furthermore, pharmacophore modeling with addition of molecular docking, DFT, MESP, ADMET were employed against (1-5) to give a new insight in biological evaluations. The pharmacophore modeling suggested that (5) has a distinctive pharmacophoric features including cationic sites, hydrogen-bond donors and acceptors which provide valuable insights into drug design for pharmacological applications. Moreover, another in silico investigations authenticate the bioactivity of (5).

Gut microbiota characteristics of Mongolian and Han populations in anti-tuberculosis drug-induced liver injury: a population-based case-control study.

BACKGROUND: The pathogenesis of anti-tuberculosis (TB) drug-induced liver injury (ADLI) is complicated and remains unclear. We aimed to analyse the relationship between the characteristics of gut microbiota and ADLI in Mongolian and Han patients with pulmonary TB and identify the most notable bacteria related to the occurrence of liver injury in those populations. METHODS: Patients with concurrent liver injury (LI) and no liver injury (ULI) before receiving first-line anti-TB drug treatment (T1) from the Han population in Tangshan and the Mongolian population in Inner Mongolia were selected as research subjects. At the time of liver injury (T2), stool samples were measured by bacterial 16S rRNA gene high-throughput sequencing to analyse and compare the differences in the gut microbiota of the LI and ULI Mongolian and Han patients at T1 and T2 and identify the differences between those patients. RESULTS: A total of 45 Mongolian and 37 Han patients were enrolled in our study. A dynamic comparison from T1 to T2 showed that the microbiota of the LI and ULI groups changed significantly from T1 to T2 in both the Mongolian and Han populations. However, there were commonalities and personality changes in the microbiota of the two ethnic groups. CONCLUSION: Differences in gut microbes in ADLI were found among the Han and Mongolian patients in our study. Ekmania and Stenotrophomonas were related to the occurrence of ADLI in Mongolian patients, while Ekmania and Ruminococcus__gnavus_group were related to the occurrence of ADLI in the Han population.

Study of drug interaction, mutant frequency and mutant prevention concentration of DFMBT against Mycobacterium tuberculosis H37RV.

In the present study 7,7-Dimethyl-4-(4-trifluoromethyl-phenylamino)-2,4,4a,6,7,8-hexahydro-benzo[d] [1,3]thiazin-5-one (DFMBT) was synthesized and evaluated for in vitro activity against Mycobacterium tuberculosis (M.tb) H37RV. Results demonstrated that at 64x MIC, DFMBT completely sterilized the TB culture from day 4 of the incubation whereas at 32 and 16x MIC, it sterilized the TB culture from day 8. The bacterial cultures were completely sterilized by DFMBT at 8x MIC from day 16 of incubation. DFMBT showed 1.5 µg/mL MIC value as compared to the standard anti-tuberculosis drugs using broth macro-dilution method. The MBC value of DFMBT was found to be 6.0 µg/mL whereas for INH, RIF, AMK and LVX the values were found to be 0.312, 0.156, 5.0 and 5.0 µg/mL, respectively. The DFMBT in combination with INH/RIF or AMK showed the ∑FIC value of 0.258, 0.252 and 0.453, respectively indicating synergistic interaction. Moreover, the value of ∑FIC for the combination of DFMBT with LVX was found to be 1.33 suggesting and additive interaction. The post antibiotic effect of DFMBT at 1x and 64x MIC was found to be 29.89 ± 10.12 and 158.75 ± 17.50 h, respectively. The DFMBT showed an MPC value of 150 µg/mL which was intermediate between INH and RIF. In summary, DFMBT exhibits bacteriostatic as well as bactericidal effect on Mycobacterium tuberculosis H37RV. It has synergistic interaction with INH, RIF and AMK anti-TB drugs, descent post antibiotic effect, mutation frequency and mutant prevention concentration. Thus, DFMBT may be developed as an effective agent as anti-TB compound.

Cerebral venous thrombosis (CVT) complicating tubercular meningitis.

BACKGROUND: Tuberculous meningitis (TBM), complicated with cerebral venous thrombosis (CVT), has been sparsely reported and needs to be investigated further. METHODS: Among those with tuberculous meningitis in Haihe Hospital, Tianjin University, 3 patients with venous sinus thrombosis were identified retrospectively. "Tuberculous meningitis" and "cerebral venous thrombosis" were used as keywords, and the retrieved literature was summarized and analyzed. Our data were combined with previously reported case data to describe this new condition. RESULTS: Among 28 patients with a median onset age of 31 years for TBM, 17 were females. The manifestations were fever, headache, and seizure. Magnetic resonance imaging (MRI) venography showed that the most common site of venous sinus thrombosis involved superior sagittal sinus, left transverse sinus, left sigmoid sinus, cavernous sinus, and straight sinus. The abnormalities found on MRI include hydrocephalus, exudates, hemorrhage, meningeal enhancement, infarction, and tuberculoma. In the acute phase, all patients received standard anti-TB treatment, and 14/28 patients received anticoagulant treatment. The mortality rate of these patients was 17.9%, and 21/28 (75%) became functionally independent. CONCLUSIONS: CVT is one of the rare complications of TMB and must be considered a differential diagnosis in patients with TBM who show poor clinical features and/or develop new neurological signs.

Factors affecting ability of TB patients to follow treatment guidelines - applying a capability approach.

BACKGROUND: Negotiating anti-Tuberculosis treatment is a complicated process comprising daily consumption of multiple medications at stipulated times and dosages, as well as periodic follow-ups and investigations, may not be uniform for all Tuberculosis (TB) patients and some may perform better than others. In this context, we conducted a study in Thiruvananthapuram district, Kerala to ascertain the ability of those suffering from TB to follow treatment guidelines. METHODS: This study used an embedded mixed methods design. We collected cross-sectional data from 135 drug sensitive pulmonary TB patients aged 18 years or above in Thiruvananthapuram, Kerala using a structured questionnaire to get the proportion of patients following all treatment guidelines. We also did eight in-depth interviews (four men and four women) from within the survey sample. The in-depth interviews were inductively analysed for getting deeper insights about reasons for the choices people made regarding the treatment guidelines. Written informed consent was taken from all participants and the study was implemented after the necessary programmatic and ethical clearances. RESULTS: Of the 105 men and 30 women studied, uninterrupted daily drug consumption was reported by 80 persons (59.3%, 95% Confidence Intervals (CI) 50.8-67.2%). Overall, 38 (28.2%, 95% CI 21.3%-36.3%) persons were able to follow all seven aspects of advised guidelines. Living in an extended/ joint family (Adjusted Odds ratio (AOR) 2.6, 95% CI 1.1-6.0), approximate monthly household expenditure of over rupees 13,500 (AOR 2.9, 95% CI 1.3-6.7) and no perceived delay in seeking initial care (AOR 3.2, 95% CI 1.2-8.7) were significantly associated with following all aspects of treatment guidelines. In-depth interviews revealed reflective treatment related behaviours were influenced by bodily experiences, moral perceptions, social construct of TB, programmatic factors and substance use. Sometimes behaviours were non-reflective also. Programmatic stress was on individual agency for changing behaviour but capability and opportunity for these were influenced social aspects like stigma, gender roles and poverty. CONCLUSION: TB patients live amidst a syndemic of biomedical and social problems. These problems influence the capabilities and opportunities of such TB patients to follow treatment guidelines. Interventions should balance focus on individual agency and social abd economic factors.

Biological and Sensing Applications of a Few 1,3,4-Oxadiazole Based Donor-Acceptor Systems.

1,3,4-Oxadiazole pharmacophore is still considered a viable biologically active scaffold for the synthesis of more effectual and broad-spectrum antimicrobial agents. Therefore, the present study is based on five 1,3,4-oxadiazole target structures, viz., CAROT, CAROP, CARON (D-A-D-A systems) and NOPON and BOPOB (D-A-D-A-D systems) bearing various bioactive heterocyclic moieties relevant to potential biological activities. Three of the compounds, CARON, NOPON and BOPOB were assessed in-vitro for their efficacy as antimicrobial agents against gram positive (Staphylococcus aureus and Bacillus cereus) and gram negative (Escherichia coli and Klebsiella pneumonia) bacteria; and two fungi, Aspergillus niger and Candida albicans; also, as an anti-tuberculosis agent against Mycobacterium tuberculosis. Most of the tested compounds displayed promising antimicrobial activity, especially CARON which was then analyzed for the minimum inhibitory concentration (MIC) studies. Similarly, NOPON portrayed the highest anti-TB activity among the studied compounds. Consequently, to justify the detected anti-TB activity of these compounds and to recognize the binding mode and important interactions between the compounds and the ligand binding site of the potential target, these compounds were docked into the active binding site of cytochrome P450 CYP121 enzyme of Mycobacterium tuberculosis, 3G5H. The docking results were in good agreement with the result of in-vitro studies. In addition, all the five compounds were tested for their cell viability and have been investigated for cell labeling applications. To conclude, one of the target compounds, CAROT was used for the selective recognition of cyanide ion by 'turn-off' fluorescent sensing technique. The entire sensing activity was examined by spectrofluorometric method and MALDI spectral studies. The limit of detection obtained was 0.14 µM.

Near-infrared molecular sensor for visualizing and tracking ONOO- during the process of anti-tuberculosis drug-induced liver damage.

Isoniazid (INH) and pyrazinamide (PZA) are both the first-line anti-tuberculosis drugs in clinical treatment. It is notable that there are serious side effects of the drugs along with upregulation of reactive nitrogen species, mainly including peripheral neuritis, gastrointestinal reactions, and acute drug-induced liver injury (DILI). Among them, DILI is the most common clinical symptom as well as the basic reason of treatment interruption, protocol change, and drug resistance. As vital reactive nitrogen species (RNS), peroxynitrite (ONOO-) has been demonstrated as a biomarker for evaluation and pre-diagnosis of drug-induced liver injury (DILI). In this work, we developed a red-emitting D-π-A type fluorescence probe DIC-NP which was based on 4'-hydroxy-4-biphenylcarbonitrile modified with dicyanoisophorone as a fluorescent reporter and diphenyl phosphinic chloride group as the reaction site for highly selective and sensitive sensing ONOO-. Probe DIC-NP displayed a low detection limit (14.9 nM) and 60-fold fluorescent enhancement at 669 nm in the sensing of ONOO-. Probe DIC-NP was successfully applied to monitor exogenous and endogenous ONOO- in living HeLa cells and zebrafish. Furthermore, we verified the toxicity of isoniazid (INH) and pyrazinamide (PZA) by taking the oxidative stress induced by APAP as a reference, and successfully imaged anti-tuberculosis drug-induced endogenous ONOO- in HepG2 cells. More importantly, we developed a series of mice models of liver injury and investigated the hepatotoxicity caused by the treatment of anti-tuberculosis drugs. At the same time, H&E of mice organs (heart, liver, spleen, lung, kidney) further confirmed the competence of probe DIC-NP for estimating the degree of drug-induced liver injury, which laid a solid foundation for medical research.

Pharmacokinetics of rifampicin, isoniazid & pyrazinamide during daily & intermittent dosing: A preliminary study.

Background & objectives: The National Tuberculosis (TB) Control Programme has transitioned from thrice-weekly to daily drug treatment regimens in India. This preliminary study was conceived to compare the pharmacokinetics of rifampicin (RMP), isoniazid (INH) and pyrazinamide (PZA) in TB patients being treated with daily and thrice weekly anti-TB treatment (ATT). Methods: This prospective observational study was undertaken in 49 newly diagnosed adult TB patients receiving either daily ATT (n=22) or thrice-weekly ATT (n=27). Plasma RMP, INH and PZA were estimated by high-performance liquid chromatography. Results: The peak concentration (Cmax) of RMP was significantly higher (RMP: 8.5 µg/ml vs. 5.5 µg/ml; P=0.003) and Cmax of INH was significantly lower (INH: 4.8 µg/ml vs. 10.9 µg/ml; P<0.001) in case of daily dosing compared to thrice-weekly ATT. Cmax of drugs and doses was significantly correlated. A higher proportion of patients had subtherapeutic RMP Cmax (8.0 µg/ml) during thrice-weekly compared to daily ATT (78% vs. 36%; P=0.004). Multiple linear regression analysis showed that Cmax of RMP was significantly influenced by the dosing rhythm, pulmonary TB and Cmax of INH and PZA by the mg/kg doses. Interpretation & conclusions: RMP concentrations were higher and INH concentrations were lower during daily ATT, suggesting that INH doses may need to be increased in case of a daily regimen. Larger studies are, however, required using higher INH doses when monitoring for adverse drug reactions and treatment outcomes.

Regulation of Gut Microflora by Lactobacillus casei Zhang Attenuates Liver Injury in Mice Caused by Anti-Tuberculosis Drugs.

The gut-liver axis may provide a new perspective for treating anti-tuberculosis drug-induced liver injury (ATDILI). Herein, the protective effect of Lactobacillus casei (Lc) was investigated by modulating gut microflora (GM) and the toll like receptor 4 (TLR4)-nuclear factor (NF)-κB-myeloiddifferentiationfactor 88 (MyD88) pathway. C57BL/6J mice were given three levels of Lc intragastrically for 2 h before administering isoniazid and rifampicin for 8 weeks. Blood, liver, and colon tissues, as well as cecal contents, were collected for biochemical and histological examination, as well as Western blot, quantitative real time polymerase chain reaction (qRT-PCR), and 16S rRNA analyses. Lc intervention decreased alkaline phosphatase (ALP), superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), and tumor necrosis factor (TNF)-α levels (p < 0.05), recovered hepatic lobules, and reduced hepatocyte necrosis to alleviate liver injury induced by anti-tuberculosis drugs. Moreover, Lc also increased the abundance of Lactobacillus and Desulfovibrio and decreased Bilophila abundance, while enhancing zona occludens (ZO)-1 and claudin-1 protein expression compared with the model group (p < 0.05). Furthermore, Lc pretreatment reduced the lipopolysaccharide (LPS) level and downregulated NF-κB and MyD88 protein expression (p < 0.05), thus restraining pathway activation. Spearman correlation analysis indicated that Lactobacillus and Desulfovibrio were positively correlated with ZO-1 or occludin protein expression and negatively correlated with pathway protein expression. Desulfovibrio had significant negative relationships with alanine aminotransferase (ALT) and LPS levels. In contrast, Bilophila had negative associations with ZO-1, occludin, and claudin-1 protein expressions and positive correlations with LPS and pathway proteins. The results prove that Lactobacillus casei can enhance the intestinal barrier and change the composition of the gut microflora. Moreover, Lactobacillus casei may also inhibit TLR4-NF-κB-MyD88 pathway activation and alleviate ATDILI.

Quinazolinones, the Winning Horse in Drug Discovery.

Quinazolines are nitrogen-containing heterocycles that consist of a benzene ring fused with a pyrimidine ring. Quinazolinones, oxidized quinazolines, are promising compounds with a wide range of biological activities. In the pharmaceutical field, quinazolinones are the building blocks of more than 150 naturally occurring alkaloids isolated from different plants, microorganisms, and animals. Scientists give a continuous interest in this moiety due to their stability and relatively easy methods for preparation. Their lipophilicity is another reason for this interest as it helps quinazolinones in penetration through the blood-brain barrier which makes them suitable for targeting different central nervous system diseases. Various modifications to the substitutions around the quinazolinone system changed their biological activity significantly due to changes in their physicochemical properties. Structure-activity relationship (SAR) studies of quinazolinone revealed that positions 2, 6, and 8 of the ring systems are significant for different pharmacological activities. In addition, it has been suggested that the addition of different heterocyclic moieties at position 3 could increase activity. In this review, we will highlight the chemical properties of quinazolinones, including their chemical reactions and different methods for their preparation. Moreover, we will try to modify some of the old SAR studies according to their updated biological activities in the last twelve years.

Puzzling Clinical Appearance of a Pancreatic Tuberculosis Case.

Tuberculosis (TB) is generally known as an infectious disease caused by Mycobacterium tuberculosis. Not only the lungs, TB can also infect various other organs. Pancreatic TB is a rare manifestation of extrapulmonary TB infection accounting for only 0-4.7% of the total TB cases worldwide. It's still intricating for clinicians to diagnose pancreatic TB due to the extremely rare prevalence and non-specific clinical signs and symptoms. Herein we report a 71-year-old male patient complaining of jaundice and weight loss. Clinical condition, laboratory and tumor markers, also MRI imaging showed no abnormality. We made the diagnosis through histopathological examination of tissues extracted from bypass biliodigestive procedure, showing granulomas, along with confirmed bacteriological analysis with Ziehl Nelsen staining. This patient received Fixed Drug Combination (FDC) of anti-tuberculosis therapy for 6 months. The patient gained weight, had an improvement of serum bilirubin level and had no remaining lesion in abdominal CT scan.

Two-stage revision for treatment of tuberculous prosthetic hip infection: an outcome analysis.

OBJECTIVES: Prosthetic joint infections (PJI) and especially tuberculosis (TB) PJI are rare diseases and hard to cure. The effectiveness of treatments for tuberculous PJI still remains a problem. The objective of this research was to indicate the success of two-stage revision replacement and also giving the associated criteria. METHODS: From 2015 to 2020, five patients with tuberculous PJI were treated with two-stage revision at Cho Ray hospital, Vietnam. We collected the dataset which included demographic data, the interval from the time of joint replacement to reported infection, records of tuberculous PJI, administration of anti-TB medications (duration, months), history of operation(s), duration of follow-up, and specific type(s) of antibiotics loaded in bone cement. The approval for this study was made by the institutional review board from Cho Ray Hospital, Vietnam. We conducted a literature review based on the keywords "PJI" and "TB" on PubMed. RESULTS: Five patients [median age 66 years (range 35-84)] had found tuberculous PJI. The median time from arthroplasty to diagnosis was 19 months (range 4-48). The diagnosis was confirmed by joint aspirates or synovial tissue. Positive PCR was also reported in all cases. The average duration of anti-tuberculosis polytherapy administration was 14.4 months. The operative techniques on five patients included debridement and using spacer loaded with 2 g streptomycin (and 2 g vancomycin if they got a coinfection) for 1 pack of bone cement, and revision arthroplasty. In most cases, the outcome of treatment using two-stage revision replacement was 80%. Overall, the auxiliary bacterial infections were recognized in three patients with tuberculous PJI and Staphylococcus aureus. Streptomycin and vancomycin were loaded in a cement spacer to increase the success rate, and tuberculous PJI was controlled for all patients. CONCLUSION: Tuberculous PJI can be controlled with two-stage revision replacement with an antibiotic-loaded cement spacer that is molded intraoperatively with custom mold and prolonged anti-tuberculosis treatment in all cases. LEVEL OF EVIDENCE: IV.

An efficient CRISPR interference-based prediction method for synergistic/additive effects of novel combinations of anti-tuberculosis drugs.

Tuberculosis (TB) is treated by chemotherapy with multiple anti-TB drugs for a long period, spanning 6 months even in a standard course. In perspective, to prevent the emergence of antimicrobial resistance, novel drugs that act synergistically or additively in combination with major anti-TB drugs and, if possible, shorten the duration of TB therapy are needed. However, their combinatorial effect cannot be predicted until the lead identification phase of the drug development. Clustered regularly interspaced short palindromic repeats interference (CRISPRi) is a powerful genetic tool that enables high-throughput screening of novel drug targets. The development of anti-TB drugs promises to be accelerated by CRISPRi. This study determined whether CRISPRi could be applicable for predictive screening of the combinatorial effect between major anti-TB drugs and an inhibitor of a novel target. In the checkerboard assay, isoniazid killed Mycobacterium smegmatis synergistically or additively in combinations with rifampicin or ethambutol, respectively. The susceptibility to rifampicin and ethambutol was increased by knockdown of inhA, which encodes a target molecule of isoniazid. Additionally, knockdown of rpoB, which encodes a target molecule of rifampicin, increased the susceptibility to isoniazid and ethambutol, which act synergistically with rifampicin in the checkerboard assay. Moreover, CRISPRi could successfully predict the synergistic action of cyclomarin A, a novel TB drug candidate, with isoniazid or rifampicin. These results demonstrate that CRISPRi is a useful tool not only for drug target exploration but also for screening the combinatorial effects of novel combinations of anti-TB drugs. This study provides a rationale for anti-TB drug development using CRISPRi.

QSAR study of antituberculosis activity of oxadiazole derivatives using DFT calculations.

Mycobacterium tuberculosis (Mtb) is the causative agent of infectious diseases worldwide. Oxadiazole derivatives have many biological activities and can be a good alternative to antimicrobial drugs. In this study, the quantitative structure-activity relationship (QSAR) of fifty-one novel oxadiazoles derivatives has been studied using the density functional theory (DFT) and statistical methods. Becke's three-parameter hybrid method and the Lee-Yang-Parr B3LYP functional employing 6-31++G (d) basis set are used to calculated quantum chemical descriptors using Gaussian09 software. The other descriptors including Lipinski, physicochemistry, topological, etc. were calculated using Chembio3d software. Statistically, the best correlation between the independent variables and the PMIC as the dependent variable was a 6-variable equation for which the correlation coefficient were as follows R2 = 0.86 and R = 0.93. Also, the values of MAE = 0.003 and Q2CV = 0.9 confirm the acceptability of the obtained model. The obtained equation shows that NRB, energy gap (ΔE), Henry's law constant, O-C, and C-N bonds length, and the Free Gibbs energy have the highest correlation with the anti-Tb activity.

Design, synthesis and anti-Mycobacterium tuberculosis evaluation of new thiazolidin-4-one and thiazolo[3,2-a][1,3,5]triazine derivatives.

In response to the urgent need to encounter infection diseases, and upon increasing concerns about the devastating effects of tuberculosis (TB), the promising thiazolidin-4-one scaffold was used as a starting point to design and synthesize seventeen new compounds, relying on the pharmacophoric features of different anti-Mycobacterium tuberculosis and antibacterial active compounds. Thiazolidin-4-one was elaborated to result in bi-functioning formation, and further ring fusion into a thiazolo[3,2-a][1,3,5]triazine, which was hybridized with different heterocyclic rings and sulfonamide moieties. All the newly synthesized compounds were evaluated for their activity against drug sensitive (DS), multi-drug resistant (MDR) and extensive drug resistant (XDR) Mycobacterium tuberculosis (Mtb) strains. Additionally, their anti-bacterial activity against several bronchitis causing-bacteria (ATCC) and their antifungal activity were assessed. Several compounds showed promising results regarding all of the mentioned assays without any antifungal activities. Particularly, compound 3 showed a promising activity against the three Mtb strains (DS, MDR and XDR) with MIC of 2.49, 9.91 and 39.72 µM, respectively. Furthermore, compound 7c revealed antituberculosis activity with MIC of 2.28, 18.14 and 36.31 µM against DS, MDR and XDR strains, respectively. Both of compounds 3 and 7c surpassed azithromycin on several bronchitis causing-bacteria and showed enhanced inhibitory activity against Mycobacterium tuberculosis enoyl-acyl carrier protein reductase (InhA), with IC50 of 3.90 and 2.47 µM, respectively. The enzymatic activity was augmented by the binding characteristics of 3 and 7c in the InhA active site. Further investigations confirmed their safety on normal cell lines, and promising predicted ADME characteristics.

Syntheses and studies of deuterated Imdiazo[1,2-a]pyridine-3-carboxamides with potent anti-tuberculosis activity and improved metabolic properties.

The imidazo[1,2-a]pyridine-3-carboxyamides (IAPs) are a unique class of compounds endowed with impressive nanomolar in vitro potency against Mycobacterium tuberculosis (Mtb) as exemplified by clinical candidate Telacebec (Q203). These compounds target mycobacterial respiration through inhibition of the QcrB subunit of cytochrome bc1:aa3 super complex resulting in bacteriostatic efficacy in vivo. Our labs have had a long-standing interest in the design and development of IAPs. However, some of these compounds suffer from short in vivo half-lives, requiring multiple daily dosing or the addition of a cytochrome P450 inhibitor for murine efficacy evaluations. Deuteration has been shown to decrease metabolism as the C-D bond is stronger than the CH bond. Herein we describe our efforts on design and synthesis of potent deuterated IAPs and the effect that deuteration has upon metabolism through microsomal stability studies.