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1.
Front Plant Sci ; 15: 1280846, 2024.
Article in English | MEDLINE | ID: mdl-38584951

ABSTRACT

The world has undergone a remarkable transformation from the era of famines to an age of global food production that caters to an exponentially growing population. This transformation has been made possible by significant agricultural revolutions, marked by the intensification of agriculture through the infusion of mechanical, industrial, and economic inputs. However, this rapid advancement in agriculture has also brought about the proliferation of agricultural inputs such as pesticides, fertilizers, and irrigation, which have given rise to long-term environmental crises. Over the past two decades, we have witnessed a concerning plateau in crop production, the loss of arable land, and dramatic shifts in climatic conditions. These challenges have underscored the urgent need to protect our global commons, particularly the environment, through a participatory approach that involves countries worldwide, regardless of their developmental status. To achieve the goal of sustainability in agriculture, it is imperative to adopt multidisciplinary approaches that integrate fields such as biology, engineering, chemistry, economics, and community development. One noteworthy initiative in this regard is Zero Budget Natural Farming, which highlights the significance of leveraging the synergistic effects of both plant and animal products to enhance crop establishment, build soil fertility, and promote the proliferation of beneficial microorganisms. The ultimate aim is to create self-sustainable agro-ecosystems. This review advocates for the incorporation of biotechnological tools in natural farming to expedite the dynamism of such systems in an eco-friendly manner. By harnessing the power of biotechnology, we can increase the productivity of agro-ecology and generate abundant supplies of food, feed, fiber, and nutraceuticals to meet the needs of our ever-expanding global population.

2.
Future Microbiol ; 18: 625-638, 2023 07.
Article in English | MEDLINE | ID: mdl-37347211

ABSTRACT

Aim: The development of a novel inhibitor targeting gyrase B and topoisomerase IV offers an opportunity to combat multidrug resistance. Methods: We investigated the activity of RBx 10080758 against Gram-positive bacteria in vitro and in vivo. Results: RBx 10080758 showed a potent 50% inhibitory concentration of 0.13 µM and 0.25 µM against gyrase B and topoisomerase IV, respectively, and exhibited strong whole-cell in vitro activity with MIC ranges of 0.015-0.06 and 0.015-0.03 µg/ml against Staphylococcus aureus and Streptococcus pneumoniae, respectively. In a rat thigh infection model with methicillin-resistant S. aureus, RBx 10080758 at 45 mg/kg exhibited a >3 log10 CFU reduction in thigh muscles. Conclusion: RBx 10080758 displayed potent activity against multiple multidrug-resistant Gram-positive bacteria with a dual-targeting mechanism of action.


Subject(s)
DNA Topoisomerase IV , Methicillin-Resistant Staphylococcus aureus , Rats , Animals , Anti-Bacterial Agents/pharmacology , Topoisomerase II Inhibitors/pharmacology , Microbial Sensitivity Tests
3.
Front Microbiol ; 12: 746110, 2021.
Article in English | MEDLINE | ID: mdl-34912307

ABSTRACT

Dengue is a serious public health concern worldwide, with ∼3 billion people at risk of contracting dengue virus (DENV) infections, with some suffering severe consequences of disease and leading to death. Currently, there is no broad use vaccine or drug available for the prevention or treatment of dengue, which leaves only anti-mosquito strategies to combat the dengue menace. The present study is an extension of our earlier study aimed at determining the in vitro and in vivo protective effects of a plant-derived phytopharmaceutical drug for the treatment of dengue. In our previous report, we had identified a methanolic extract of aerial parts of Cissampelos pareira to exhibit in vitro and in vivo anti-dengue activity against all the four DENV serotypes. The dried aerial parts of C. pareira supplied by local vendors were often found to be mixed with aerial parts of another plant of the same Menispermaceae family, Cocculus hirsutus, which shares common homology with C. pareira. In the current study, we have found C. hirsutus to have more potent anti-dengue activity as compared with C. pareira. The stem part of C. hirsutus was found to be more potent (∼25 times) than the aerial part (stem and leaf) irrespective of the extraction solvent used, viz., denatured spirit, hydro-alcohol (50:50), and aqueous. Moreover, the anti-dengue activity of stem extract in all the solvents was comparable. Hence, an aqueous extract of the stem of C. hirsutus (AQCH) was selected due to greater regulatory compliance. Five chemical markers, viz., Sinococuline, 20-Hydroxyecdysone, Makisterone-A, Magnoflorine, and Coniferyl alcohol, were identified in fingerprinting analysis. In a test of primary dengue infection in the AG129 mice model, AQCH extract at 25 mg/kg body weight exhibited protection when administered four and three times a day. The AQCH was also protective in the secondary DENV-infected AG129 mice model at 25 mg/kg/dose when administered four and three times a day. Additionally, the AQCH extract reduced serum viremia and small intestinal pathologies, viz., viral load, pro-inflammatory cytokines, and vascular leakage. Based on these findings, we have undertaken the potential preclinical development of C. hirsutus-based phytopharmaceutical, which could be studied further for its clinical development for treating dengue.

4.
Curr Drug Deliv ; 17(4): 343-347, 2020.
Article in English | MEDLINE | ID: mdl-32077827

ABSTRACT

BACKGROUND: Rifampicin is known to degrade at the acidic pH of the stomach, especially in the presence of isoniazid. Although isoniazid also degrades partially, its degradation is reversible. OBJECTIVE: Presently, we provide a proof of the fact that the simultaneous oral administration of rifampicin (RIF), upon incorporation into solid lipid nanoparticles (RIF-SLNs), with isoniazid (INH) overcomes its INH-induced degradation and improves its oral bioavailability in rats. METHODS: Solid lipid nanoparticles of RIF (RIF-SLNs) were prepared using a novel and patented method. The effect of INH was investigated on in vivo bioavailability of RIF both in its free and encapsulated (RIF-SLNs) form, after oral administration to rats. RESULTS: Cmax and AUC0-∞ of RIF increased 158 % and 125 %, respectively, upon incorporation into SLNs versus free RIF when combined with INH. The Tmax decreased from 5.67 h to 3.3 h, and the plasma concentration of RIF remained above its MIC (8 µg/ml) at all the tested time points starting with 15 min, when administered as RIF-SLNs in combination with INH. CONCLUSION: The results confirm the scope of combining RIF-SLNs with INH to overcome the bioavailability of free RIF when combined with INH, especially in fixed dose combinations.


Subject(s)
Isoniazid/pharmacokinetics , Lipids/pharmacokinetics , Nanoparticles/chemistry , Rifampin/pharmacokinetics , Administration, Oral , Animals , Biological Availability , Capsules/administration & dosage , Capsules/chemistry , Capsules/pharmacokinetics , Isoniazid/administration & dosage , Isoniazid/blood , Lipids/administration & dosage , Lipids/blood , Male , Nanoparticles/administration & dosage , Rats , Rats, Wistar , Rifampin/administration & dosage , Rifampin/blood
5.
Bioorg Med Chem Lett ; 27(15): 3454-3459, 2017 08 01.
Article in English | MEDLINE | ID: mdl-28587823

ABSTRACT

A non-diaryl quinoline scaffold 6,7-dihydropyrazolo[1,5-a]pyrazin-4-one was identified by screening of diverse set of compounds against M. smegmatis ATP synthase. Herein, we disclose our efforts to develop the structure activity relationship against Mycobacterium tuberculosis (Mtb.H37Rv strain) around the identified hit 1. A scaffold hopping approach was used to identify compounds 14a, 14b and 24a with improved activity against MTb.H37Rv.


Subject(s)
ATP Synthetase Complexes/antagonists & inhibitors , Antitubercular Agents/chemistry , Antitubercular Agents/pharmacology , Mycobacterium tuberculosis/enzymology , Quinolines/chemistry , Quinolines/pharmacology , ATP Synthetase Complexes/metabolism , Antitubercular Agents/chemical synthesis , Drug Design , Humans , Mycobacterium tuberculosis/drug effects , Pyrazines/chemical synthesis , Pyrazines/chemistry , Pyrazines/pharmacology , Quinolines/chemical synthesis , Structure-Activity Relationship , Tuberculosis/drug therapy , Tuberculosis/microbiology
6.
J Am Soc Nephrol ; 27(3): 877-86, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26386072

ABSTRACT

Pulmonary hypertension (PH) is associated with poor outcomes in the dialysis and general populations, but its effect in CKD is unclear. We evaluated the prevalence and predictors of PH measures and their associations with long-term clinical outcomes in patients with nondialysis-dependent CKD. Chronic Renal Insufficiency Cohort (CRIC) Study participants who had Doppler echocardiography performed were considered for inclusion. PH was defined as the presence of estimated pulmonary artery systolic pressure (PASP) >35 mmHg and/or tricuspid regurgitant velocity (TRV) >2.5 m/s. Associations between PH, PASP, and TRV and cardiovascular events, renal events, and all-cause mortality were examined using Cox proportional hazards models. Of 2959 eligible participants, 21% (n=625) had PH, with higher rates among those with lower levels of kidney function. In the multivariate model, older age, anemia, lower left ventricular ejection fraction, and presence of left ventricular hypertrophy were associated with greater odds of having PH. After adjusting for relevant confounding variables, PH was independently associated with higher risk for death (hazard ratio, 1.38; 95% confidence interval, 1.10 to 1.72) and cardiovascular events (hazard ratio, 1.23; 95% confidence interval, 1.00 to 1.52) but not renal events. Similarly, TRV and PASP were associated with death and cardiovascular events but not renal events. In this study of patients with CKD and preserved left ventricular systolic function, we report a high prevalence of PH. PH and higher TRV and PASP (echocardiographic measures of PH) are associated with adverse outcomes in CKD. Future studies may explain the mechanisms that underlie these findings.


Subject(s)
Cardiovascular Diseases/epidemiology , Hypertension, Pulmonary/complications , Hypertension, Pulmonary/epidemiology , Renal Insufficiency, Chronic/complications , Adult , Age Factors , Aged , Anemia/epidemiology , Arterial Pressure , Cause of Death , Cross-Sectional Studies , Echocardiography , Female , Glomerular Filtration Rate , Humans , Hypertension, Pulmonary/mortality , Hypertrophy, Left Ventricular/epidemiology , Male , Middle Aged , Prevalence , Pulmonary Artery/physiopathology , Renal Insufficiency, Chronic/physiopathology , Risk Factors , Stroke Volume , Tricuspid Valve Insufficiency/mortality , United States/epidemiology , Ventricular Dysfunction, Left/epidemiology , Young Adult
7.
PLoS Negl Trop Dis ; 9(12): e0004255, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26709822

ABSTRACT

BACKGROUND: Dengue, a mosquito-borne viral disease, poses a significant global public health risk. In tropical countries such as India where periodic dengue outbreaks can be correlated to the high prevalence of the mosquito vector, circulation of all four dengue viruses (DENVs) and the high population density, a drug for dengue is being increasingly recognized as an unmet public health need. METHODOLOGY/PRINCIPAL FINDINGS: Using the knowledge of traditional Indian medicine, Ayurveda, we developed a systematic bioassay-guided screening approach to explore the indigenous herbal bio-resource to identify plants with pan-DENV inhibitory activity. Our results show that the alcoholic extract of Cissampelos pariera Linn (Cipa extract) was a potent inhibitor of all four DENVs in cell-based assays, assessed in terms of viral NS1 antigen secretion using ELISA, as well as viral replication, based on plaque assays. Virus yield reduction assays showed that Cipa extract could decrease viral titers by an order of magnitude. The extract conferred statistically significant protection against DENV infection using the AG129 mouse model. A preliminary evaluation of the clinical relevance of Cipa extract showed that it had no adverse effects on platelet counts and RBC viability. In addition to inherent antipyretic activity in Wistar rats, it possessed the ability to down-regulate the production of TNF-α, a cytokine implicated in severe dengue disease. Importantly, it showed no evidence of toxicity in Wistar rats, when administered at doses as high as 2g/Kg body weight for up to 1 week. CONCLUSIONS/SIGNIFICANCE: Our findings above, taken in the context of the human safety of Cipa, based on its use in Indian traditional medicine, warrant further work to explore Cipa as a source for the development of an inexpensive herbal formulation for dengue therapy. This may be of practical relevance to a dengue-endemic resource-poor country such as India.


Subject(s)
Antiviral Agents/pharmacology , Cissampelos/chemistry , Dengue Virus/drug effects , Dengue/drug therapy , Plant Extracts/pharmacology , Animals , Antigens, Viral/immunology , Antigens, Viral/metabolism , Antiviral Agents/therapeutic use , Biological Assay , Cell Line , Dengue/virology , Dengue Virus/classification , Dengue Virus/immunology , Dengue Virus/physiology , Female , Gene Expression Regulation, Viral/drug effects , Humans , India , Male , Mice , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Extracts/therapeutic use , Rats , Rats, Wistar , Serogroup , Viral Load/drug effects , Virus Replication/drug effects
8.
Am J Clin Oncol ; 38(1): 103-7, 2015 Feb.
Article in English | MEDLINE | ID: mdl-23608827

ABSTRACT

Lung cancer is the leading cause of cancer-related death in both developed and developing countries with unacceptably high mortality even for early-stage cancers. Present guidelines do not recommend adjuvant chemotherapy for stage I non-small cell lung carcinoma and prompts a search for a prognostic marker that would separate stage I patients into 2 groups, those who would benefit and those who would not benefit from adjuvant treatment. Studies during the last decade showed that the gene expression profiling can be the biomarker being sought. Many gene expression profiling have been found and reported from the analysis of surgical specimens of resected lung cancers during the last decade, and many of them had been shown to have an excellent predictive accuracy. These profiles used in the studies had not only different gene combinations but also different number of genes and methods of identification. Researchers have used microarray assays, RT-quantitative polymerase chain reaction, and more recently microRNA-based techniques to achieve this goal. Unfortunately, most of the profiles were not sufficiently validated and/or were not used in prospective phase III studies. This review focuses on major studies in the field, future prospects, as well as the lessons learned so far. It is shown that the gene expression profiles have a good chance of being implemented in future everyday practice.


Subject(s)
Adenocarcinoma/genetics , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Squamous Cell/genetics , Gene Expression Regulation, Neoplastic/genetics , Lung Neoplasms/genetics , RNA, Messenger/genetics , Adenocarcinoma/pathology , Adenocarcinoma/therapy , Carcinoma, Non-Small-Cell Lung/pathology , Carcinoma, Non-Small-Cell Lung/therapy , Carcinoma, Squamous Cell/pathology , Carcinoma, Squamous Cell/therapy , Chemotherapy, Adjuvant/methods , Gene Expression Profiling/methods , Humans , Lung Neoplasms/pathology , Lung Neoplasms/therapy , MicroRNAs/genetics , Neoplasm Staging , Patient Selection , Pneumonectomy , Prognosis , Protein Array Analysis , Reverse Transcriptase Polymerase Chain Reaction
9.
Case Rep Hematol ; 2013: 269268, 2013.
Article in English | MEDLINE | ID: mdl-24198982

ABSTRACT

The most common cause of a neck mass in young adults is hyperplastic lymphadenopathy consequent to infection and inflammation. Castleman's disease (CD), an unusual benign lymphoproliferative disorder, infrequently causes neck masses. It occurs in unicentric (UCD) and multicentric (MCD) forms and is associated with human immunodeficiency virus (HIV), human herpes virus 8 (HHV-8), and Kaposi's sarcoma. We present the third known association between MCD and previous immune thrombocytopenia in the absence of HIV and HHV-8 infection and review its association with other autoimmune disorders and attendant implications for pathogenesis. Finally, we summarize the current approach to therapy.

10.
PLoS One ; 8(5): e64595, 2013.
Article in English | MEDLINE | ID: mdl-23717637

ABSTRACT

Dengue is a mosquito-borne viral disease with a global prevalence. It is caused by four closely-related dengue viruses (DENVs 1-4). A dengue vaccine that can protect against all four viruses is an unmet public health need. Live attenuated vaccine development efforts have encountered unexpected interactions between the vaccine viruses, raising safety concerns. This has emphasized the need to explore non-replicating dengue vaccine options. Virus-like particles (VLPs) which can elicit robust immunity in the absence of infection offer potential promise for the development of non-replicating dengue vaccine alternatives. We have used the methylotrophic yeast Pichia pastoris to develop DENV envelope (E) protein-based VLPs. We designed a synthetic codon-optimized gene, encoding the N-terminal 395 amino acid residues of the DENV-2 E protein. It also included 5' pre-membrane-derived signal peptide-encoding sequences to ensure proper translational processing, and 3' 6× His tag-encoding sequences to facilitate purification of the expressed protein. This gene was integrated into the genome of P. pastoris host and expressed under the alcohol oxidase 1 promoter by methanol induction. Recombinant DENV-2 protein, which was present in the insoluble membrane fraction, was extracted and purified using Ni(2+)-affinity chromatography under denaturing conditions. Amino terminal sequencing and detection of glycosylation indicated that DENV-2 E had undergone proper post-translational processing. Electron microscopy revealed the presence of discrete VLPs in the purified protein preparation after dialysis. The E protein present in these VLPs was recognized by two different conformation-sensitive monoclonal antibodies. Low doses of DENV-2 E VLPs formulated in alum were immunogenic in inbred and outbred mice eliciting virus neutralizing titers >1,1200 in flow cytometry based assays and protected AG129 mice against lethal challenge (p<0.05). The formation of immunogenic DENV-2 E VLPs in the absence of pre-membrane protein highlights the potential of P. pastoris in developing non-replicating, safe, efficacious and affordable dengue vaccine.


Subject(s)
Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , Dengue Virus/immunology , Viral Envelope Proteins/immunology , Virion/immunology , Amino Acid Sequence , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Cell Line , Dengue/prevention & control , Dengue/virology , Humans , Mice , Mice, 129 Strain , Mice, Inbred BALB C , Molecular Sequence Data , Pichia , Protein Multimerization , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/immunology , Vaccination , Viral Envelope Proteins/biosynthesis , Viral Envelope Proteins/chemistry , Viral Vaccines/immunology , Virion/ultrastructure
11.
BMJ Case Rep ; 20122012 Jul 03.
Article in English | MEDLINE | ID: mdl-22761209

ABSTRACT

A 67-year-old female who was diagnosed with ulcerative colitis in 2001, presented with a soft tissue mass in the middle of her back of 4 months duration in April 2011. It was excised; however it recurred at the same site in September 2011. Wide excision of the mass was done. Pathology revealed T1aNxM0 pleomorphic malignant fibrous histiocytoma or undifferentiated pleomorphic sarcoma. Whole body bones scan and staging CT scan of the chest, abdomen and pelvis was negative for distant metastasis. She received local radiotherapy at the site of excision. No chemotherapy was given.


Subject(s)
Colitis, Ulcerative/complications , Histiocytoma, Malignant Fibrous/complications , Neoplasm Recurrence, Local/surgery , Skin Neoplasms/complications , Aged , Azathioprine/therapeutic use , Colitis, Ulcerative/drug therapy , Female , Histiocytoma, Malignant Fibrous/pathology , Histiocytoma, Malignant Fibrous/therapy , Humans , Immunosuppressive Agents/therapeutic use , Neoplasm Recurrence, Local/radiotherapy , Radiotherapy, Adjuvant , Skin Neoplasms/pathology , Skin Neoplasms/therapy
12.
Antimicrob Agents Chemother ; 54(11): 4789-93, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20713679

ABSTRACT

We screened 194 Mycobacterium tuberculosis strains isolated from tuberculosis (TB) patients in Delhi and neighboring regions in India to identify the prevalence of extensive drug resistance (XDR) in clinical isolates. Among these, 104 isolates were found to be multidrug resistant (MDR), and 6 were identified as XDR isolates, which was later confirmed by antimicrobial susceptibility testing against the respective drug screening panel. Genotyping was carried out by amplifying and sequencing the following genes: rpoB (rifampin), katG (isoniazid), gyrA (fluoroquinolones), and rrs (amikacin, kanamycin, and capreomycin). Our analyses indicated that mutations at the hot spots of these genes were positively correlated with drug resistance in clinical isolates. The key mutation observed for rpoB was in the codon for amino acid position 531 (S531L), and other mutations were seen in the hot spot, including those encoding Q510P, L511H, D516V, and H526Y mutations. We identified S315T and R463L substitutions encoded in the katG locus. An S95T substitution encoded in the gyrA locus was the most common mutation observed in fluoroquinolone-resistant isolates. In addition, we saw D94G and D94N mutations encoded in the QRDR region. The 16S rRNA (rrs) gene encoded mainly the A1401G mutation and an additional mutation, G1484T, resulting in ribosomal modifications. Taken together, the data in this report clearly establish the presence of phenotypically distinct XDR strains in India by molecular profiling and further identify specific mutational hot spots within key genes of XDR-TB strains.


Subject(s)
Antitubercular Agents/pharmacology , Extensively Drug-Resistant Tuberculosis/microbiology , Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/genetics , Amikacin/pharmacology , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Capreomycin/pharmacology , DNA Gyrase/chemistry , DNA Gyrase/genetics , DNA Mutational Analysis , DNA-Directed RNA Polymerases , Fluoroquinolones/pharmacology , India , Isoniazid/pharmacology , Kanamycin/pharmacology , Microbial Sensitivity Tests , Mutation , Mycobacterium tuberculosis/pathogenicity , Point Mutation/genetics , Polymerase Chain Reaction , Rifampin/pharmacology
13.
Int J Antimicrob Agents ; 33(3): 280-4, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19091517

ABSTRACT

RBx 1000075 and RBx 1000276, the new investigational oxazolidinones, have an extended spectrum of in vitro activity against Gram-positive pathogens and showed minimum inhibitory concentrations (MICs) lower than comparator drugs. MIC for 90% of the organisms (MIC(90)) values of RBx 1000075, RBx 1000276 and linezolid against the isolates tested were, respectively: methicillin-sensitive Staphylococcus aureus, 0.25, 1 and 4 microg/mL; methicillin-resistant S. aureus (MRSA), 0.5, 2 and 4 microg/mL; methicillin-sensitive Staphylococcus epidermidis, 0.25, 1 and 2 microg/mL; methicillin-resistant S. epidermidis, 0.5, 1 and 2 microg/mL; and enterococci, 0.25, 1 and 4 microg/mL. Against respiratory pathogens, MIC(90) values were: Streptococcus pneumoniae, 0.125, 0.5 and 2 microg/mL; Streptococcus pyogenes, 1, 0.5 and 2 microg/mL; and Moraxella catarrhalis, 0.5, 2 and 4 microg/mL. In vivo efficacies of RBx 1000075 and RBx 1000276 were evaluated in murine systemic infection against S. aureus (MRSA 562) and in a pulmonary infection model against S. pneumoniae ATCC 6303. In murine systemic infection, RBx 1000075 and RBx 1000276 showed efficacy against MRSA 562, exhibiting a 50% effective dose (ED(50)) of 6.25 and 9.92 mg/kg body weight for once-daily administration and 4.96 and 5.56 mg/kg body weight for twice-daily administration, respectively, whereas for linezolid the corresponding ED(50) values were 9.9 and 5.56 mg/kg body weight. In pulmonary infection with S. pneumoniae ATCC 6303, 50% survival was observed with RBx 1000075 at 50mg/kg once daily, whereas 60% survival was observed with RBx 1000276 at 50mg/kg thrice daily. The absolute oral bioavailabilities of RBx 1000075 and RBx 1000276 were 48% and 73%, with half-lives of 13.5 and 3.2h, respectively. RBx 1000075 and RBx 1000276 are promising investigational oxazolidinones against Gram-positive pathogens.


Subject(s)
Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/pharmacokinetics , Oxazolidinones/pharmacology , Oxazolidinones/pharmacokinetics , Administration, Oral , Animals , Anti-Bacterial Agents/administration & dosage , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Half-Life , Mice , Microbial Sensitivity Tests , Oxazolidinones/administration & dosage , Pneumonia, Bacterial/drug therapy , Sepsis/drug therapy , Survival Analysis
14.
Int J Antimicrob Agents ; 25(6): 464-8, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15885988

ABSTRACT

The decision to develop a new chemical entity should not only be based on its ability to inhibit multidrug-resistant tuberculosis (MDR-TB) strains but also on its ability to enter macrophages and be active against intracellular bacteria. RBx 7644 and RBx 8700, two novel extended spectrum oxazolidinones, were investigated for their activity against sensitive and MDR isolates of Mycobacterium tuberculosis and for activity against bacteria within a macrophage cell line. RBx 8700 showed excellent in vitro activity against sensitive as well as MDR M. tuberculosis strains with MIC(50) and MIC(90) values of 0.032 and 0.25mg/L (sensitive) and 0.25 and 1.0mg/L (MDR) strains. The corresponding MIC(50) and MIC(90) values of RBx 7644, linezolid, rifampicin and isoniazid were 8 and 16; 32 and 64; 64 and 64; 64 and 64 mg/L, respectively. RBx 8700 and rifampicin were bactericidal at 0.5 and 0.25mg/L when tested intracellularly whereas linezolid reduced the count by 100-fold at a concentration of 8 mg/L. In combination studies with standard antimycobacterial drugs, RBx 8700 did not show any antagonistic effect.


Subject(s)
Antitubercular Agents/pharmacology , Furans/pharmacology , Macrophages/microbiology , Mycobacterium tuberculosis/drug effects , Oxazoles/pharmacology , Oxazolidinones/pharmacology , Acetamides/pharmacology , Animals , Cell Line , Drug Antagonism , Furans/chemistry , Isoniazid/pharmacology , Linezolid , Mice , Microbial Sensitivity Tests , Molecular Structure , Oxazoles/chemistry , Oxazolidinones/chemistry , Rifampin/pharmacology
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