Avaliação da atividade micobactericida de desinfetantes químicos utilizando a técnica de cultivo em camada de ágar Middlebrook 7H11 / Evaluation of mycobactericidal activity of chemical disinfectants using the Middlebrook 7H11 agar medium technique

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The mycobactericidal activity of five chemical disinfectants was evaluated against a strain of Mycobacterium bovis isolated from a goat, typified by PCR (polymerase chain reaction) and with 32 days of growth in the Stonebrink medium. The disinfectants were tested using the modified thin layer Middlebrook 7H11 cultivation technique and it was compared to the test made in tubes with Stonebrink medium, which is tradicionally used at the Bacterian Zoonosis Laboratory of the Veterinary Medicice Faculty of the University of São Paulo. The five disinfectants were: "A" was the control group; "B"- sodium hypochlorite (2,5% of active chlorine); "C"- glutaraldehyde (2 %); "D"- peracetic acid (0,25 %) and hydrogen peroxide (5 %); "E" - iodine compounds (2,6%) e "F"- fenolic compounds (orto-fenilfeno 12,243 g; orto-benzil paraclorofenol 11,080 g; para-terceario amilfeno 4,122 g.). The products were diluted according to label instructions. The culture media used for the isolation procedure and preparation of the bacterian suspension were the Stonebrink and modified Middlebrook 7H11 medium. The assays were performed either in the presence or absence of organic matter, at temperatures of 4 °C and 21 ± 2°C The colony counting results were transformed into reduction percentages for the statistical analysis and concluded in: the modified thin layer Middlebrook 7H11 cultivation technique permitted an earlier visualization of the colonies and was practible for the realization of the disinfectants tests; the five disinfectants showed mycobactericidal activity and the peracetic acid had the best performance followed by the sodium hypochlorite. The mycobactericidal activity of the iodine compound was unsatisfactory when in the presence of organic matter.

ASSUNTO(S)

caprine tuberculosis desinfetantes mycobacterium bovis disinfectants caprino middlebrook tuberculose mycobacterium bovis middlebrook

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