title: Enzymatic inactivation and reactivation of chloramphenicol by Mycobacterium tuberculosis and Mycobacterium bovis.
abstract: Mycobacterium tuberculosis and Mycobacterium bovis are inhibited by chloramphenicol. Chloramphenicol acetyltransferase (CAT) converts chloramphenicol to inactive diacetyl chloramphenicol, but a mycobacterial carboxylesterase hydrolyzes the diacetyl product to active chloramphenicol. The esterase activity was eliminated by proteinase K and heat treatment. Protein extracts of M. tuberculosis and M. bovis hydrolyzed four other ester substrates. cat was inserted into the chromosome of both M. tuberculosis and M. bovis resulting in a level of chloramphenicol resistance that could be used to select for transformants. CAT assays in the resistant strain of M. tuberculosis showed interference due to esterase activity. This interference could be eliminated with the addition of a heating step.
authors.affiliation: Department of Veterans Affairs Medical Center, Tuberculosis Research Laboratory, 5901 East Seventh Street, Long Beach, CA 90822, USA. chuck@sohaskey.com
authors.forename: Charles D
authors.initials: CD
authors.lastname: Sohaskey
mesh_terms: D001711:Biotransformation; D043182:Carboxylesterase / Q000378:metabolism*; D002701:Chloramphenicol / Q000378:metabolism* / Q000494:pharmacology*; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics* / Q000378:metabolism; D002702:Chloramphenicol Resistance / Q000502:physiology; D019286:Endopeptidase K / Q000378:metabolism; D006358:Hot Temperature; D009163:Mycobacterium bovis / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D014169:Transformation, Bacterial
chemical_list: D002701:Chloramphenicol; D015500:Chloramphenicol O-Acetyltransferase; D043182:Carboxylesterase; D019286:Endopeptidase K