TY - JOUR
T1 - In vitro activity of a novel antimycobacterial compound, N-octanesulfonylacetamide, and its effects on lipid and mycolic acid synthesis
AU - Parrish, N. M.
AU - Houston, T.
AU - Jones, P. B.
AU - Townsend, C.
AU - Dick, J. D.
PY - 2001
Y1 - 2001
N2 - β-Sulfonyl carboxamides have been proposed to serve as transition-state analogues of the β-ketoacyl synthase reaction involved in fatty acid elongation. We tested the efficacy of N-octanesulfonylacetamide (OSA) as an inhibitor of fatty acid and mycolic acid biosynthesis in mycobacteria. Using the BACTEC radiometric growth system, we observed that OSA inhibits the growth of several species of slow-growing mycobacteria, including Mycobacterium tuberculosis (H37Rv and clinical isolates), the Mycobacterium avium complex (MAC), Mycobacterium bovis BCG, Mycobacterium kansasii, and others. Nearly all species and strains tested, including isoniazid and multidrug resistant isolates of M. tuberculosis, were susceptible to OSA, with MICs ranging from 6.25 to 12.5 μg/ml. Only three clinical isolates of M. tuberculosis (CSU93, OT2724, and 401296), MAC, and Mycobacterium paratuberculosis required an OSA MIC higher than 25.0 μg/ml. Rapid-growing mycobacterial species, such as Mycobacterium smegmatis, Mycobacterium fortuitum, and others, were not susceptible at concentrations of up to 100 μg/ml. A 2-dimensional thin-layer chromatography system showed that OSA treatment resulted in a significant decrease in all species of mycolic acids present in BCG. In contrast, mycolic acids in M. smegmatis were relatively unaffected following exposure to OSA. Other lipids, including polar and nonpolar extractable classes, were unchanged following exposure to OSA in both BCG and M. smegmatis. Transmission electron microscopy of OSA-treated BCG cells revealed a disruption in cell wall synthesis and incomplete septum formation. Our results indicate that OSA inhibits the growth of several species of mycobacteria, including both isoniazid-resistant and multidrug resistant strains of M. tuberculosis. This inhibition may be the result of OSA-mediated effects on mycolic acid synthesis in slow-growing mycobacteria or inhibition via an undescribed mechanism. Our results indicate that OSA may serve as a promising lead compound for future antituberculous drug development.
AB - β-Sulfonyl carboxamides have been proposed to serve as transition-state analogues of the β-ketoacyl synthase reaction involved in fatty acid elongation. We tested the efficacy of N-octanesulfonylacetamide (OSA) as an inhibitor of fatty acid and mycolic acid biosynthesis in mycobacteria. Using the BACTEC radiometric growth system, we observed that OSA inhibits the growth of several species of slow-growing mycobacteria, including Mycobacterium tuberculosis (H37Rv and clinical isolates), the Mycobacterium avium complex (MAC), Mycobacterium bovis BCG, Mycobacterium kansasii, and others. Nearly all species and strains tested, including isoniazid and multidrug resistant isolates of M. tuberculosis, were susceptible to OSA, with MICs ranging from 6.25 to 12.5 μg/ml. Only three clinical isolates of M. tuberculosis (CSU93, OT2724, and 401296), MAC, and Mycobacterium paratuberculosis required an OSA MIC higher than 25.0 μg/ml. Rapid-growing mycobacterial species, such as Mycobacterium smegmatis, Mycobacterium fortuitum, and others, were not susceptible at concentrations of up to 100 μg/ml. A 2-dimensional thin-layer chromatography system showed that OSA treatment resulted in a significant decrease in all species of mycolic acids present in BCG. In contrast, mycolic acids in M. smegmatis were relatively unaffected following exposure to OSA. Other lipids, including polar and nonpolar extractable classes, were unchanged following exposure to OSA in both BCG and M. smegmatis. Transmission electron microscopy of OSA-treated BCG cells revealed a disruption in cell wall synthesis and incomplete septum formation. Our results indicate that OSA inhibits the growth of several species of mycobacteria, including both isoniazid-resistant and multidrug resistant strains of M. tuberculosis. This inhibition may be the result of OSA-mediated effects on mycolic acid synthesis in slow-growing mycobacteria or inhibition via an undescribed mechanism. Our results indicate that OSA may serve as a promising lead compound for future antituberculous drug development.
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U2 - 10.1128/AAC.45.4.1143-1150.2001
DO - 10.1128/AAC.45.4.1143-1150.2001
M3 - Article
C2 - 11257028
AN - SCOPUS:0035077016
SN - 0066-4804
VL - 45
SP - 1143
EP - 1150
JO - Antimicrobial agents and chemotherapy
JF - Antimicrobial agents and chemotherapy
IS - 4
ER -