Author(s): Ukuku DO, Shelef LA
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Abstract The influence of nisin on intracellular ATP and cell numbers of Listeria monocytogenes strain Scott A was determined and compared with the effect of amplicillin and streptomycin under similar conditions. In the presence of nisin (3-12 micrograms/ml), intracellular ATP and cell numbers decreased rapidly during the first hour at 35 degrees C and extracellular ATP increased. Cell numbers and intracellular ATP increased after 3 h of incubation. No effect was observed in cells treated with ampicillin (3-12 micrograms/ml) and streptomycin (15-60 micrograms/ml) during the first hour. However, concentrations of > or = 3 micrograms/ml ampicillin and > or = 30 micrograms/ml streptomycin were listeriostatic after 3 h of incubation. Progressive loss of viability and reduction of intracellular ATP were observed in resting cells in PBS (pH 7.2) containing increasing concentrations of the antimicrobials. Rapid accumulation of extracellular ATP, observed immediately after treatment with nisin but not with the antibiotics, supports the reported collapse of proton motive force in L. monocytogenes by nisin.
This article was published in J Biolumin Chemilumin
and referenced in Journal of Microbial & Biochemical Technology