A note to the biological activity of benzoxazine derivatives containing the thioxo group.

New 3-benzyl-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones and 3-benzyl-2H-1,3-benzoxazine-2,4(3H)-dithiones were synthesized. The compounds were tested for in vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium kansasii and Mycobacterium avium. The replacement of the carbonyl group by the thiocarbonyl group increased the antimycobacterial activity. The most active derivatives were more active than isonicotinhydrazide (INH). The cytotoxicity and the antiproliferative activity were studied as well.

Preparation and in-vitro evaluation of 4-benzylsulfanylpyridine-2-carbohydrazides as potential antituberculosis agents.

A set of 4-benzylsulfanylpyridine-2-carbohydrazides was synthesized and evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, non-tuberculous mycobacteria, and multidrug-resistant M. tuberculosis. The activities expressed as the minimum inhibitory concentration (MIC) fall into a range of 2 to 125 micromol/L, most often 4 to 32 micromol/L. The results revealed that the substituents on the benzyl moiety do not influence the antimycobacterial efficacy. The substances exhibited similar activities against sensitive and resistant strains of M. tuberculosis. Furthermore, compounds show low antiproliferative effect and cytotoxicity.

New antituberculotics originated from salicylanilides with promising in vitro activity against atypical mycobacterial strains.

A new series of 30 N-protected amino acid esters were prepared as a part of ongoing search for new anti-tuberculosis active salicylanilides. The esters possess high in vitro activity against Mycobacterium tuberculosis, Mycobacterium avium, and two strains of Mycobacterium kansasii, where one is an isolate from the patient, with MIC in the range 1-32 micromol/L for all tested strains. The prepared esters can be considered as prodrugs with better bio-availability and as more efficient transport forms through the mycobacterial cell membranes due to the higher lipophilicity. The experimental and calculated lipophilicity, stability, antituberculotic activity, cytotoxicity as well as the quantitative structure-activity relationships (QSARs) explored by the Intelligent Problem Solver (IPS) in Trajan Neural Network Simulator 6.0 are presented.

N-benzylsalicylthioamides: highly active potential antituberculotics.

A gseries of 29 new derivatives of N-benzylsalicylthioamides was synthesized and the compounds were tested for in-vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium kansasii, and Mycobacterium avium. The activity was analyzed by quantitative structure-activity relationship (QSAR). Activity increased with increasing lipophilicity and electron donating effect of the substituents in the acyl moiety and decreased with the electrophilic superdelocalizability of the molecules. The most active compounds are more active than isoniazid (INH) and are active against INH-resistant potential pathogenic strains of mycobacterium.

Preparation and in vitro evaluation of benzylsulfanyl benzoxazole derivatives as potential antituberculosis agents.

A set of 2-benzylsulfanyl derivatives of benzoxazole was synthesized and evaluated for their in vitro antimycobacterial activity against Mycobacterium tuberculosis, non-tuberculous mycobacteria and multidrug-resistant M. tuberculosis. The activities were expressed as the minimum inhibitory concentration (MIC) in mmol/L. The substances showed similar activity against all tested strains. The lead compounds in the set, dinitro derivatives exhibited significant activity against both sensitive and resistant strains of M. tuberculosis and also against non-tuberculous mycobacteria. To facilitate drug design of benzoxazole as potential antituberculosis agent, we have explored the quantitative structure-activity relationship (QSAR). We demonstrated that lower lipophilicity has significant contribution to activity. Dinitrobenzylsulfanyl derivative of benzoxazole represents the promising small-molecule synthetic antimycobacterials.

Highly active potential antituberculotics: 3-(4-alkylphenyl)-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones and 3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dihiones substituted in ring-B by halogen.

A series of 6-chloro-3-(4-alkylphenyl)-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones, 7-chloro-3-(4-alkylphenyl)-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones, 6-bromo-3-(4-alkylphenyl)-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones, 6,8-dibromo-3-(4-alkylphenyl)-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones, 6-chloro-3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dithiones, 7-chloro-3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dithiones, 6-bromo-3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dithiones and 6,8-dibromo-3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dithiones was synthesized. The compounds exhibited in-vitro activity against Mycobacterium tuberculosis, M. kansasii (two strains), and M. avium. 6-bromo-3-(4-propylphenyl)-4-thioxo-2H-1,3-benzoxazin-2(3H)-one and 6-bromo-3-(4-propylphenyl)-2H-1,3-benzoxazin-2,4(3H)-dithione are the most active compounds against M. tuberculosis. The activity is similar to isoniazid (INH). The compounds under study have a broad spectrum of activity against potential pathogenic strains. The replacement of the oxo group by thioxo group of 3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-diones often led to an improvement in the antimycobacterial activity against M. tuberculosis.

Incidence of nontuberculous mycobacteria in four hot water systems using various types of disinfection.

The objective of this study was to determine the incidence of nontuberculous mycobacteria (NTM) in hot water systems of 4 selected hospital settings. The hospitals provided the following types of disinfection for their hot water systems: hydrogen peroxide and silver, thermal disinfection, chlorine dioxide, and no treatment (control). In each building, 6 samples were collected from 5 sites during a 3 month period. NTM were detected in 56 (46.7%) of 120 samples; the CFU counts ranged from 10 to 1625 CFU/L. The detected NTM species were the pathogens Mycobacterium kansasii, Mycobacterium xenopi, and Mycobacterium fortuitum and the saprophyte Mycobacterium gordonae. The most common to be isolated was M. xenopi, which was present in 51 samples. The hot water systems differed significantly in the incidence of NTM. NTM were not detected in the system treated by thermal disinfection, and a relatively low incidence (20% positive samples) was found in the system disinfected with chlorine dioxide. However, a high incidence was found in the control system with no additional disinfection (70% positives) and in the system using hydrogen peroxide and silver (97% positives). Water temperatures above 50 degrees C significantly limited the occurrence of NTM.

Salicylanilide acetates: synthesis and antibacterial evaluation.

A new series of salicylanilide acetates was synthesized and evaluated for their in vitro antifungal and antituberculotic activity. Some of the evaluated compounds possessed comparable or better antifungal activity than a fluconazole standard. All these compounds exhibited very good potential and their in vitro activity against drug resistant and sensitive clinical isolates of Mycobacteria were found to be equivalent or better than a standard of isoniazide, a well-known first-line drug for tuberculosis treatment.

The oriented development of antituberculotics (Part II): halogenated 3-(4-alkylphenyl)-1,3-benzoxazine-2,4-(3H)-diones.

Based on our previous studies, 21 new halogenated 3-(4-alkylphenyl)-1,3-benzoxazine-2,4-(3H)-diones were synthesized by the reaction of salicylanilides and methyl-chloroformate. All compounds were screened in vitro against three different strains of mycobacterium, and Free-Wilson method was used to establish structure-activity relationships. 6-Bromo-3-(4-butylphenyl)-1,3-benzoxazine-2,4-(3H)-dione 3b proved to be the most active compound of the series.

A new modification of anti-tubercular active molecules.

The connection of two active molecules across an easily released bridge as a new type of potentially active molecule has been studied. The synthesis is based on derivatives that originate from isonicotinoyl hydrazide, pyrazinamide, p-aminosalicylic acid (PAS), ethambutol, and ciprofloxacin. The lipophilicity, hydrolysis (stability of the compounds), and antituberculotic activity as well as the structure-lipophilicity and structure-activity relationships are discussed.

The oriented development of antituberculotics: salicylanilides.

On the basis of our previous results 22 salicylanilides were synthesized. The compounds were tested for in vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium kansasii, and Mycobacterium avium. The Free-Wilson method was used to evaluate structure-antimycobacterial activity relationships. 4-Chloro-N-(4-propylphenyl)salicylamide and 5-chloro-N-(4-propylphenyl)salicylamide were selected for preclinical studies.

Molecular epidemiology of tuberculosis in the Czech Republic, 2004: analysis of M. tuberculosis complex isolates originating from the city of prague, south Moravia and the Moravian-Silesian region.

OBJECTIVES: To compare M. tuberculosis complex genotypes from representative regions of the Czech Republic in order to estimate changes in strain prevalence and in the extent of imported drug-resistant tuberculosis. METHODS: Primary M. tuberculosis complex isolates (n=155) and follow-up isolates (n=15) from 155 patients from the first half of 2004 (98 from Prague, 37 from South Moravia and 35 from the Moravian-Silesian region) were genotyped by IS6110-RFLP, spoligotyping, and partly by VNTR-genotyping. RESULTS: Based on IS6110-RFLP, 110 of 155 (71%) primary isolates were unique. Forty-five isolates (29%) were found in 15 clusters comprising two to six patients and all but one cluster were also discriminated by MIRU-VNTR-genotyping. Four clusters comprised patients from different regions, and six were ongoing for several years. An indication of MDR-strain transmission was found in one instance. All four Beijing-type isolates with any resistance were associated with immigration from Eastern Europe. CONCLUSIONS: The molecular epidemiological data of this period-prevalence, population based study and its comparison to earlier investigations point to a low extent of clustering between M. tuberculosis complex isolates in representative regions of the Czech Republic. Few clusters extending geographically and/or over several years were identified, providing a means for an in-depth analysis of risk factors of transmission. Beijing genotype isolates were shown to increase in prevalence to reach 6.5%. Drug resistant isolates of this genotype were associated with immigration of from Eastern Europe, although direct transmission of a resistant isolate was probable only in one of eleven cases.

A note on the antitubercular activities of 1-aryl-5-benzylsulfanyltetrazoles.

A set of 32 1-phenyl-5-benzylsulfanyltetrazoles substituted on the phenyl ring as well as on the benzyl moiety was synthesized. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis. The activity against M. tuberculosis becomes higher with increasing electron-accepting properties of the substituents on the phenyl ring. On the other hand, any substitution on the benzylic moiety decreases the activity.

[Microbiological diagnosis of mycobacterioses caused by Mycobacterium haemophilum]. / Mikrobiologická diagnostika mykobacterióz vyvolaných Mycobacterium haemophilum.

INTRODUCTION: According to foreign literature Mycobacterium haemophilum causes diseases of the skin, subcutis and lymph nodes in immunocompetent individuals, while in AIDS patients and in subjects after kidney transplantations it is responsible for osteomyelitis and disseminated infections. MATERIAL AND METHODS: The authors tested the possibility of using a BioFM medium with the X-factor for the detection of Mycobacterium haemophilum in clinical samples and Middlebrook's 7H9 medium with ADC and the X-factor to establish the sensitivity of strains to antimicrobials using the MIC method. CONCLUSIONS: Given the favourable results of preliminary tests the use of the BioFM medium was included among the routine methods applied at the department. In one year Mycobacterium haemophilum was detected with this method in 3 patients presenting extrapulmonary mycobacteriosis.

Heterocyclic isosters of antimycobacterial salicylanilides.

A series of 64 derivatives of substituted heterocyclic analogues of salicylanilides was synthesized. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium avium and two strains of Mycobacterium kansasii. For the QSAR study, the combination of Free-Wilson approach with Hansch approach was used. The molecules were separated on the heterocyclic and salicyl moieties and the study of influences of electronic and hydrophobic properties was used as well. The compounds are a new group of potential anti-tuberculotics.

Highly lipophilic benzoxazoles with potential antibacterial activity.

A series of lipophilic 2-substituted 5,7-di-tert-butylbenzoxazoles was prepared in average yields by the reaction of 3,5-di-tert-butyl-1,2-benzoquinone with amino acids and dipeptides bearing N-terminal glycine. Dipeptides having other N-terminal amino acids undergo oxidative deamination. 5,7-Di-tert-butylbenzoxazoles have shown activity against Mycobacterium tuberculosis and some nontuberculous strains where isoniazid has been inactive. Antifungal activity was mediocre.

Synthesis and antimycobacterial activity of pyridylmethylsulfanyl and naphthylmethylsulfanyl derivatives of benzazoles, 1, 2, 4-triazole, and pyridine-2-carbothioamide/-2-carbonitrile.

A set of four types of benzazoles, 1, 2, 4-triazole, and pyridine-2-carbonitrile/-2-carbothioamide substituted with 1-naphthylmethylsulfanyl or pyridylmethylsulfanyl was prepared to modify the structure of benzylsulfanyl derivatives of the above-mentioned heterocycles. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, M. avium, and two strains of M. kansasii. The activities were expressed as the minimum inhibitory concentration (MIC). The MIC values fall into a range of 2 to >1000 micromol/L. Introduction of a pyridyl moiety into the molecule mostly decreased the activity. A naphthyl moiety did not influence the activity in comparison with a phenyl. The most active substances were 4-(3-pyridylmethylsulfanyl)pyridine-2-carbothioamide (7b) (MIC = 2 - >62.5 micromol/L) and 4-(1-naphthylmethylsulfanyl)pyridine-2-carbothioamide (7d) (MIC = 2 - >32 micromol/L).

Antimycobacterial N-pyridinylsalicylamides, isosters of salicylamides.

The series of derivatives of substituted N-pyridinylsalicylamides were synthesized. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium avium and two strains of Mycobacterium kansasii. In the quantitative structure activity relationships analysis (QSAR), the Free-Wilson and Hansch approaches were used but the analysis was not significant. (The standard deviations of regression coefficients were greater than the values of the coefficients). The molecules were separated the heterocyclic and salicyl moiety in the molecules, and the study of influences of substituents on salicyl moiety was used, as well. 5-chloro-pyridin-2-yl, and the substitution of the salicyl moiety by chlorine in position 4 or 5 had the strongest influence on the increase in antimycobacterial activity.

Synthesis and antimycobacterial activity of 1,2,4-triazole 3-benzylsulfanyl derivatives.

Series of 3-benzylsulfanyl derivatives of 1,2,4-triazole and 4-methyl-1,2,4-triazole were synthesized by alkylation of starting triazole-3-thiol with appropriately substituted benzyl halide. All members of the set were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, M. avium, and two strains of M. kansasii. The activities were expressed as the minimum inhibitory concentration. The compounds exhibited only a moderate or slight antimycobacterial activity. Minimum inhibitory concentrations fall into a range of 32->1000 micromol/l. The most active substances bear two nitro groups or a thioamide group on the benzyl moiety. As regards the cytotoxicity effect, the evaluated compounds can be considered as moderately toxic.

3-Benzyl-2H-1,3-benzoxazine-2,4(3H)-diones, a new group of antimycobacterial compounds against potentially pathogenic strains.

A series of derivatives of 3-benzyl-2H-benzoxazine-2,4(3H)-dione substituted in positions 6, 7 or 8 on the benzoxazine, and in positions 3 or 4 on the benzyl moiety was synthesized. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium avium and two strains of Mycobacterium kansasii. The disadvantage of the compounds is in their low solubility in water. The antimycobacterial activity of N-benzylsalicylamides correlates with that of 3-benzyl-2H-1,3-benzoxazin-2,4(3H)-diones and depends on the partition coefficients and electronic indexes.