Atividade antibacteriana dos fitocompostos timol e carvacrol frente a cepas de Escherichia coli produtoras de B-lactamases de espectro estendido.

Abstract

With the increasing spread of resistance mechanisms, the treatment of bacterial infections has become increasingly problematic, since the number of effective antimicrobials in the treatment of these microorganisms becomes increasingly reduced. Among the various forms of bacterial adaptation, the production of extended spectrum betalactamases (ESBL) is an important resistance mechanism present in the Enterobacteriaceae family. Based on the information presented, the present study aimed to study the antimicrobial activity of thymol and carvacrol phytochemicals against Escherichia coli strains producing extended spectrum betalactamases and to determine the minimum inhibitory concentration (MIC) of thymol and carvacrol. The methodology was carried out at the Microbiology Laboratory (J11) at the Education and Health Center of the Federal University of Campina Grande, state of Paraíba, Brazil. For the determination of the MIC of the selected phytochemicals, bacterial strains of ESBL (C-18, C-21, C-20, C-24, C-25, 24, 65) producing E. coli were used from outpatients and the 96-hole microdilution technique was performed by serial dilution at a ratio of two, reserving the last column for growth control of the microorganisms, all procedures being performed in triplicate and incubation of the microplates in a bacteriological oven at a temperature of ± 37 ˚C with a variation of 2 ˚C. After a 24 hour incubation period the plates were removed from the oven and the MIC of the tested phytochemicals was read. Carvacrol MIC showed concentrations of 64 μg / mL for strain 65 and 128 μg / mL for C-18, C-20, C-21, C-24, C-25 and 24 strains. thymol, the MIC was determined as: 1,024 μg / mL for the C-25 strain; 512 μg / mL for C-18, C-21, 24 and 65 strains; 256 μg / mL for strain C-24; and 128 μg / mL for the C-20 strain. By means of the Minimal bactericidal concentration (CBM), it was possible to determine the type of activity presented by the phytoconstituent being of the bacteriostatic type, since growth above 3 CFUs was observed in all the plaques.