Estudos radiométricos sobre a oxidação de (U-14C) L-aminoácidos por micobactérias sensíveis e resistentes a drogas

A radiometric assay system has been used to study oxidation patterns of (U-14C) L-amino acids by drug-susceptible and drug-resistant mycobacteria. Drug-susceptible M. tuberculosis (H37Rv TMC 102 and Erdman) along with the drug-resistant organism M. tuberculosis (H37 Rv TMC 303), M. bovis, M. avium, M. intracellulare, M. kansasii and M. chelonei were used. The organisms were inoculated into a sterile reaction system with liquid 7H9 medium and one of the (U-14C) L-amino acids. Each organism displayed a different pattern of amino acid oxidation, but these patterns were not distinctive enough for identification of the organism. Complex amino acids such as proline, phenylalanine and tyrosine were of no use in identification of mycobacteria, since virtually all organisms failed to oxidize them. There was no combination of substrates able to separate susceptible from resistant organisms.Um sistema radiométrico foi utilizado para estudar os padrões de oxidação dos (U-14C) L-aminoácidos por micobactérias sensíveis e resis tentes a drogas. Foram usadas duas cepas do M. tuberculosis sensíveis a todas as drogas, H37Rv e Erdman. As micobactérias resistentes foram M. tuberculosis H37Rv resistente a 5 ug/ml de hidrazida, M. bovis, M. avium, M. intracellulare, M. kansasii e M. chelonei. As micobac térias foram inoculadas em frascos estéreis contendo o meio líquido 7H9 e um dos (U-14C) L-aminoácidos. Cada micobactéria apresentou um padrão de oxidação de aminoácidos, mas estes padrões não foram suficientemente diferentes para identificá-la. Aminoácidos complexos como a prolina, fenilalanina e tirosina não tiveram utilidade na identificação das micobactérias, pois praticamente todos os microorganismos foram incapazes de oxidá-los. Nenhuma combinação de aminoácidos foi capaz de separar as micobactérias sensíveis das resistentes a drogas

Esudos radiométricos sobre a oxidação de (1-14C) ácidos graxos por micobactérias sensíveis e resistentes a drogas

Um sistema radiométrico foi utilizado para estudar os padrões de oxidação dos (1-14C) ácidos graxos por microorganismos do gênero Mycobacterium sensíveis e resistentes a drogas. Foram usadas duas cepas do M. tuberculosis sensíveis a todas as drogas, H37Rv e Erdman. As micobactérias resistentes foram M. tuberculosis H37Rv resistente a 5 ug/ml de hidrazida, M. bovis, M. avium, M. intracellulare, M. kansasii e M. chelonei. As micobactérias foram inoculadas em frascos estéreis contendo o meio líquido 7H9 com 10% do complexo albumina-dextrose-catalase e 1,0 uCi de um dos (1-14C) ácidos graxos (butírico, hexanoico, octanoico, decanóico, láurico, mirístico, plamítico, esteárico, olêico, linolêico, linolênico). Os frascos foram incubados a 37°C e o 14C0(2) produzido pelas micobactérias foi medido durante 3 dias, com uma máquina Bactec-R-301. Embora cada micobactéria apresentasse um padrão distinto de oxidação de ácido graxo, estes padrões não foram suficientemente diferentes para identificá-la. Nenhuma combinação de ácidos graxos nem a oxidação preferencial de ácidos graxos de cadeias longas ou curtas foi capaz de separar as micobactérias resistentes das sensíveis. Outras experiências com um maior número de micobactérias sensíveis, incluindo estudo da assimilação de substâncias marcadas, são necessárias para se tentar a diferenciação entre as micobactérias sensíveis e as resistentes a drogas.A radiometric assay system has been used to study oxidation patterns of (1-14C) fatty acids by drug-susceptible and drug-resistant organisms of the genus Mycobacterium. Two strains of M. tuberculosis susceptible to all drugs, H37Rv and Erdman, were used. Drug-resistant organisms included in this investigation were M. tuberculosis H37Rv resistant to 5 ug/ml isoniazid, M. bovis, M. avium, M. intracellular, M. kansasii and M. chelonei. The organisms were inoculated in sterile reaction vials containing liquid 7H9 medium, 10% ADC enrichment and 1.0 uCi of one of the (1-14C) fatty acids (butyric, hexánoic, octanoic, decanoic, lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic). Vials were incubated at 37°C and the 14CO2 envolved was measured daily for 3 days with a Bactec R-301 instrument. Although each individual organism displayed a different pattern of fatty oxidation, these patterns were not distinctive enough for identification of the organism. No combination of fatty acids nor preferential oxidation of long chain or of short chain fatty acids were able to separate susceptible from resistant organisms. Further investigation with a larger number of drug susceptible mycobacteria including assimilation studies and oxidation of other substrates may be required to achieve a distinction between drug-susceptible and drug-resistant mycobacteria

Radiometric studies on the oxidation of (1-14c) fatty acids by drug-susceptible and drug-resistant mycobacteria

A radiometric assay system has been used to study oxidation patterns of (1-14C) fatty acids by drug-susceptible and drug-resistant organisms of the genus Mycobacterium. Two strains of M. tuberculosis susceptible to all drugs, H37Rv and Erdman, were used. Drug-resistant organisms included in this investigation were M. tuberculosis H37Rv resistant to 5 ug/ml isoniazid, M. bovis, M. avium, M. intracellular, M. kansasii and M. chelonei. The organisms were inoculated in sterile reaction vials containing liquid 7H9 medium, 10% ADC enrichment and 1.0 uCi of one of the (1-14C) fatty acids (butyric, hexánoic, octanoic, decanoic, lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic). Vials were incubated at 37°C and the 14CO2 envolved was measured daily for 3 days with a Bactec R-301 instrument. Although each individual organism displayed a different pattern of fatty oxidation, these patterns were not distinctive enough for identification of the organism. No combination of fatty acids nor preferential oxidation of long chain or of short chain fatty acids were able to separate susceptible from resistant organisms. Further investigation with a larger number of drug susceptible mycobacteria including assimilation studies and oxidation of other substrates may be required to achieve a distinction between drug-susceptible and drug-resistant mycobacteria