New Flexible Analogues of 8-Aza-7-deazapurine Nucleosides as Potential Antibacterial Agents.

A variety of ribo-, 2'-deoxyribo-, and 5'-norcarbocyclic derivatives of the 8-aza-7-deazahypoxanthine fleximer scaffolds were designed, synthesized, and screened for antibacterial activity. Both chemical and chemoenzymatic methods of synthesis for the 8-aza-7-deazainosine fleximers were compared. In the case of the 8-aza-7-deazahypoxanthine fleximer, the transglycosylation reaction proceeded with the formation of side products.

PLGA Carriers for Controlled Release of Levofloxacin in Anti-Tuberculosis Therapy.

Levofloxacin (LFX) is a highly effective anti-tuberculosis drug with a pronounced bactericidal activity against (). In this work, an "organic solvent-free" approach has been used for the development of polylactic-co-glycolic acid (PLGA) microparticles and scaffolds containing LFX at a therapeutically significant concentration, providing for its sustained release. To achieve the target, both nonpolar supercritical carbon dioxide and polar supercritical trifluoromethane have been used.

Evaluation of a new assay for nontuberculous mycobacteria species identification in diagnostic material and cultures.

The purpose of the present study was to evaluate a real-time PCR system for 12 nontuberculous mycobacteria (NTM) species identification developed by Central Tuberculosis Research Institute (CTRI; Moscow, Russia) in cooperation with Syntol LLC (Moscow, Russia). NTM cultures (210 strains, 19 species), Mycobacterium tuberculosis complex (MTBC) cultures (21 strains, 2 species), non-mycobacterial microorganisms (18 strains, 13 species) were used for the first stage of the assay evaluation. Clinical samples (sputum, N = 973) positive for smear microscopy and MTBC/NTM DNA by a PCR-based screening assay collected from 819 patients were used for specificity and sensitivity evaluation.

Impact of GeneXpert MTB/RIF® on treatment initiation and outcomes of RIF-resistant and RIF-susceptible TB patients in Vladimir TB dispensary, Russia.

Background: The main advantage of GeneXpert MTB/RIF® (Xpert) molecular diagnostic technology is the rapid detection of M.tuberculosis DNA and mutations associated with rifampicin (RIF) resistance for timely initiation of appropriate treatment and, consequently, preventing further transmission of the disease. We assessed time to treatment initiation and treatment outcomes of RIF-resistant and RIF-susceptible TB patients diagnosed and treated in Vladimir TB Dispensary, Russia in 2012, before and after implementation of GeneXpert MTB/RIF® diagnostic technology.

Interaction of 5-substituted pyrimidine nucleoside analogues and M.Tuberculosis: A view through an electron microscope.

The data of transmission electron microscopy (TEM) on morphology of M. tuberculosis H37Rv bacterial cells treated with four analogues of pyrimidine nucleosides with different substituents at 5 position of base are presented. We showed that the growth of M.

Investigation of 5'-Norcarbocyclic Nucleoside Analogues as Antiprotozoal and Antibacterial Agents.

Carbocyclic nucleosides have long played a role in antiviral, antiparasitic, and antibacterial therapies. Recent results from our laboratories from two structurally related scaffolds have shown promising activity against both and several parasitic strains. As a result, a small structure activity relationship study was designed to further probe their activity and potential.

New assay to diagnose and differentiate between Mycobacterium tuberculosis complex and nontuberculous mycobacteria.

The purpose of the present study was to create a real-time PCR test system allowing simultaneous detection of nontuberculous mycobacteria (NTM) and Mycobacterium tuberculosis complex (MTBC) both in culture and sputum. NTM cultures (18 strains, 18 species), MTBC cultures (16 strains, 2 species) and non-mycobacterial microorganisms from the collection of the Central Research TB Institute (CTRI) were used for the preliminary evaluation of the test system. 301 NTM cultures from patients with mycobacteriosis were used to assess the sensitivity of the developed test system.

Novel 5'-Norcarbocyclic Pyrimidine Derivatives as Antibacterial Agents.

A series of novel 5'-norcarbocyclic derivatives of 5-alkoxymethyl or 5-alkyltriazolyl-methyl uracil were synthesized and the activity of the compounds evaluated against both Gram-positive and Gram-negative bacteria. The growth of was completely inhibited by the most active compounds at a MIC of 67 μg/mL (mc²155) and a MIC of 6.7⁻67 μg/mL (VKPM Ac 1339).

Severe Tuberculosis in Humans Correlates Best with Neutrophil Abundance and Lymphocyte Deficiency and Does Not Correlate with Antigen-Specific CD4 T-Cell Response.

It is generally thought that ()-specific CD4 Th1 cells producing IFN-γ are essential for protection against tuberculosis (TB). In some studies, protection has recently been associated with polyfunctional subpopulation of -specific Th1 cells, i.e.

Dual-targeted anti-TB/anti-HIV heterodimers.

HIV and M. tuberculosis are two intersecting epidemics making the search for new dual action drugs against both pathogens extremely important. Here, we report on the synthesis and suppressive activities of five dual-targeted HIV/TB compounds.

Antigen-Specific IFN- Responses Correlate with the Activity of Infection but Are Not Associated with the Severity of Tuberculosis Disease.

IFN- is a key cytokine in antituberculosis (TB) defense. However, how the levels of its secretion affect () infection is not clear. We have analyzed associations between IFN- responses measured in QuantiFERON®-TB Gold In-tube (QFT) assay, TB disease severity, and infection activity.

Mycobacterium tuberculosis Type II Toxin-Antitoxin Systems: Genetic Polymorphisms and Functional Properties and the Possibility of Their Use for Genotyping.

Various genetic markers such as IS-elements, DR-elements, variable number tandem repeats (VNTR), single nucleotide polymorphisms (SNPs) in housekeeping genes and other groups of genes are being used for genotyping. We propose a different approach. We suggest the type II toxin-antitoxin (TA) systems, which play a significant role in the formation of pathogenicity, tolerance and persistence phenotypes, and thus in the survival of Mycobacterium tuberculosis in the host organism at various developmental stages (colonization, infection of macrophages, etc.

Multidrug-Resistant Tuberculosis Treatment Outcomes in Relation to Treatment and Initial Versus Acquired Second-Line Drug Resistance.

Background: Resistance to second-line drugs develops during treatment of multidrug-resistant (MDR) tuberculosis, but the impact on treatment outcome has not been determined.

Methods: Patients with MDR tuberculosis starting second-line drug treatment were enrolled in a prospective cohort study. Sputum cultures were analyzed at a central reference laboratory.

Resistance to pyrazinamide in Russian Mycobacterium tuberculosis isolates: pncA sequencing versus Bactec MGIT 960.

Resistance to pyrazinamide (PZA) may impact clinical outcome of anti-tuberculosis chemotherapy. PZA susceptibility testing using MGIT 960 is not reliable and little information is available on the prevalence of PZA resistance in Russia. A collection of 64 clinical isolates of Mycobacterium tuberculosis, including 35 multidrug resistant and extensively drug-resistant (MDR/XDR), was analyzed for PZA resistance using MGIT 960, Wayne test, and sequencing of PZA resistance genes pncA, rpsA and panD.

5-Arylaminouracil Derivatives: New Inhibitors of Mycobacterium tuberculosis.

Three series of 5-arylaminouracil derivatives, including 5-(phenylamino)uracils, 1-(4'-hydroxy-2'-cyclopenten-1'-yl)-5-(phenylamino)uracils, and 1,3-di-(4'-hydroxy-2'-cyclopenten-1'-yl)-5-(phenylamino)uracils, were synthesized and screened for potential antimicrobial activity. Most of compounds had a negative effect on the growth of the Mycobacterium tuberculosis H37Rv strain, with 100% inhibition observed at concentrations between 5 and 40 μg/mL. Of those, 1-(4'-hydroxy-2'-cyclopenten-1'-yl)-3-(4‴-hydroxy-2‴-cyclopenten-1‴-yl)-5-(4″-butyloxyphenylamino)uracil proved to be the most active among tested compounds against the M.

Extensive drug resistance acquired during treatment of multidrug-resistant tuberculosis.

Background: Increasing access to drugs for the treatment of multidrug-resistant (MDR) tuberculosis is crucial but could lead to increasing resistance to these same drugs. In 2000, the international Green Light Committee (GLC) initiative began to increase access while attempting to prevent acquired resistance.

Methods: To assess the GLC's impact, we followed adults with pulmonary MDR tuberculosis from the start to the end of treatment with monthly sputum cultures, drug susceptibility testing, and genotyping.

Inhibition of Mycobacterium tuberculosis strains H37Rv and MDR MS-115 by a new set of C5 modified pyrimidine nucleosides.

Two sets of pyrimidine nucleoside derivatives bearing extended alkyloxymethyl or alkyltriazolidomethyl substituents at position 5 of the nucleobase were synthesized and evaluated as potential antituberculosis agents. The impact of modifications at 3'- and 5'-positions of the carbohydrate moiety on the antimycobacterial activity and cytotoxicity was studied. The highest effect was shown for 5-dodecyloxymethyl-2'-deoxyuridine, 5-decyltriazolidomethyl-2'-deoxyuridine, and 5-dodecyltriazolidomethyl-2'-deoxycytidine.

The synthesis and antituberculosis activity of 5'-nor carbocyclic uracil derivatives.

A series of new carbocyclic uracil derivatives were synthesized and evaluated as potential antituberculosis agents. Racemic 1-[4'-hydroxy-2'-cyclopenten-1'-yl]-5-tetradecynyluracil completely inhibited the growth of Mycobacterium tuberculosis H37Rv in vitro at a concentration of 10 μg/ml. Individual (+) and (-) isomers of the above uracil derivative were isolated and showed the same level of activity against two strains of Mycobacterium tuberculosis: laboratory sensitive (H37Rv) and clinical resistant to five top antituberculosis drugs (MS-115).

Prevalence of and risk factors for resistance to second-line drugs in people with multidrug-resistant tuberculosis in eight countries: a prospective cohort study.

Background: The prevalence of extensively drug-resistant (XDR) tuberculosis is increasing due to the expanded use of second-line drugs in people with multidrug-resistant (MDR) disease. We prospectively assessed resistance to second-line antituberculosis drugs in eight countries.

Methods: From Jan 1, 2005, to Dec 31, 2008, we enrolled consecutive adults with locally confirmed pulmonary MDR tuberculosis at the start of second-line treatment in Estonia, Latvia, Peru, Philippines, Russia, South Africa, South Korea, and Thailand.

Mass-spectrometry based minisequencing method for the rapid detection of drug resistance in Mycobacterium tuberculosis.

A MALDI TOF MS based minisequencing method has been developed and applied for the analysis of rifampin (RIF)- and isoniazid (INH)-resistant M. tuberculosis strains. Eight genetic markers of RIF resistance-nucleotide polymorphisms located in RRDR of rpoB gene, and three of INH resistance including codon 315 of katG gene and -8 and -15 positions of the promoter region of fabG1-inhA operon were worked out.

Molecular characteristics of rifampicin- and isoniazid-resistant Mycobacterium tuberculosis isolates from the Russian Federation.

Objectives: Three Mycobacterium tuberculosis genetic loci--rpoB and katG genes and the fabG1(mabA)-inhA operon promoter region--were studied to reveal the mutations associated with rifampicin and isoniazid resistance.

Methods: Four hundred and twelve isolates of M. tuberculosis from different regions of the Russian Federation were collected during 1997-2005.