Mycobacterium kansasii

In this work, we describe the activity of ACH-702 against clinical isolates of Mycobacterium tuberculosis and six different nontuberculous mycobacteria. The MIC 50 and MIC 90 of both susceptible and drug-resistant M. tuberculosis strains tested were 0.0625 and 0.125 μg/ml, respectively. The MIC 50 and MIC 90 values for Mycobacterium fortuitum isolates were 0.0625 μg/ml in both cases; Mycobacterium avium complex isolates showed MIC 50 and MIC 90 values of 0.25 and 4 μg/ml, respectively.

A series of amino-5-[(substituted) phenyl]-3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H- 1-pyrazolylmethanethione were synthesized by the reaction between thiosemicarbazide and chalcones and were tested for their antimycobacterial activity in vitro against Mycobacterium tuberculosis H37Rv and INH resistant Mycobacterium tuberculosis using bactec method. Among the synthesized compounds, compound (4b), amino-5-(4-chlorophenyl)-3-(4-hydroxy-3-methylphenyl)-4, 5-dihydro-H-1-pyrazolylmethanethione was found to be the most active agent against Mycobacterium tuberculosis H37Rv (MTB) and INH resistant Mycobacterium tuberculosis (INHR-MTB) with minimum inhibitory concentration of 0.43 microM . When compared to INH-compound (4b) was found to be 1.62 fold and 26.41 fold more active against MTB and INHR-MTB, respectively.

A series of 3-substituted 5-hydroxy-5-trifluoro[chloro]methyl-1H-1-isonicotinoyl-4,5-dihydropyrazoles (2a–i) were synthesised by the cyclocondensation reaction of 4-methoxy-1,1,1-trifluoro[chloro]-4-(substituted)-alk-3-en-2-ones (1a–i) and isoniazid (INH). Their in vitro antimicrobial activity was tested against INH-susceptible Mycobacterium tuberculosis H37Rv, INH-resistant clinical M. tuberculosis isolates and non-tuberculous mycobacteria. Amongst the synthesised compounds, 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-(isonicotinoyl)-pyrazole (2a) and 5-hydroxy-3-(4-methylphenyl)-5-trifluoromethyl-4,5-dihydro-1H-1-(isonicotinoyl) pyrazole (2d) were found to be the two most active agents against susceptible M. tuberculosis and several INH-resistant strains. The compound 3-(2-furyl)-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-(isonicotinoyl)pyrazole (2f) was active against all the INH-resistant strains regardless of the genetic background at concentrations two- to four-fold its minimum inhibitory concentration against M. tuberculosis H37Rv. These compounds were inhibitors of mycolic acid biosynthesis, in agreement with the utilisation of the INH scaffold for their design. Interestingly, the most active compound against M. tuberculosis, 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-(isonicotinoyl)-pyrazole (2a), was even more potent than INH against non-tuberculous mycobacteria.

A new series of 27 diethyl 2-(phenylcarbamoyl)phenyl phosphorothioates (thiophosphates) was synthesized, characterized by NMR, IR and CHN analyses and evaluated against Mycobacterium tuberculosis H37Rv, Mycobacterium avium and two strains of Mycobacterium kansasii. The best activity against M. tuberculosis was found for O-{4-bromo-2-[(3,4-dichlorophenyl)carbamoyl]phenyl} O,O-diethyl phosphorothioate (minimum inhibitory concentration of 4 µM). The highest activity against nontuberculous mycobacteria was exhibited by O-(5-chloro-2-{[4-(trifluoromethyl)phenyl]carbamoyl}-phenyl) O,O-diethyl phosphorothioate with MIC values from 16 µM. Prepared thiophosphates were also evaluated against acetylcholinesterase from electric eel and butyrylcholinesterase from equine serum. Their inhibitory activity was compared to that of the known cholinesterases inhibitors galanthamine and rivastigmine. All tested compounds showed a higher (for AChE inhibition) and comparable (for BChE inhibition) activity...

Mycobacterium kansasiiis one of the most common causes of pulmonary disease resulting from nontuberculous mycobacteria (NTM). It is also the most frequently isolated NTM species from clinical specimens in Poland. The aim of this study was to investigate the distribution ofM. kansasiisubtypes among patients suspected of having pulmonary NTM disease. Fifty clinical isolates ofM. kansasiirecovered from as many patients with suspected mycobacterial lung disease between 2000 and 2010 in Poland were genotyped by PCR-restriction enzyme analysis (PCR-REA) of partialhsp65gene.Mycobacterium kansasiisubtype I was the only genotype to be identified among the isolates, both disease-associated and non-disease-associated. Isolation ofM. kansasiisubtype I from clinical specimens may be indicative of infection but may also merely represent colonization.

Mycobacterium kansasii is an opportunistic pathogen and one of the most commonly encountered species in individuals with lung disease. We here report the complete genome sequence of 12 clinical isolates of M. kansasii from patients with pulmonary disease in Brazil.

Although the mechanisms underlying the cytotoxic effect of NK cells on tumor cells and intracellular bacteria have been studied extensively, it remains unclear how these cells kill extracellular bacterial pathogens. In this study, we examine how human NK cells kill Mycobacterium kansasii and M.tb. The underlying mechanism is contact dependent and requires two cytolytic proteins: perforin and granulysin. Mycobacteria induce enhanced expression of the cytolytic proteins via activation of the NKG2D/NCR cell-surface receptors and intracellular signaling pathways involving ERK, JNK, and p38 MAPKs. These results suggest that NK cells use similar cellular mechanisms to kill both bacterial pathogens and target host cells. This report reveals a novel role for NK cells, perforin, and granulysin in killing mycobacteria and highlights a potential alternative defense mechanism that the immune system can use against mycobacterial infection.