RT Journal Article SR Electronic(1) A1 Ohya, S. A1 Xiong, H. A1 Tanabe, Y. A1 Arakawa, M. A1 Mitsuyama, M.YR 1998 T1 Killing mechanism of Listeria monocytogenes in activated macrophages as determined by an improved assay system JF Journal of Medical Microbiology, VO 47 IS 3 SP 211 OP 215 DO https://doi.org/10.1099/00222615-47-3-211 PB Microbiology Society, SN 1473-5644, AB Exposure of Listeria monocytogenes to gentamicin 5 mg/L for 4 h resulted in the killing of most extracellular bacteria, but had no effect on the survival of bacteria inside macrophages. Higher concentrations of gentamicin caused a reduction in the number of intracellular bacteria. This effect was associated with cellular uptake of gentamicin, but was unaffected by activation of macrophages by interferon-γ and lipopolysaccharide. In experiments in which exposure to gentamicin 5 mg/L for 4 h was used to kill extracellular bacteria, killing by activated macrophages was impaired when O2 − production was inhibited by superoxide dismutase, but not when nitric oxide production was blocked by NG -monomethyl-l-arginine. These data suggest that the reactive oxygen intermediates are more important than nitric oxide in the killing of L. monocytogenes, at least in macrophages activated in vitro. , UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-47-3-211