Light effect and reactive oxygen species in the action of ciprofloxacin on Staphylococcus aureus

BECERRA, M. C.; SARMIENTO, M.; PÁEZ, P. L.; ARGÜELLO, G.; ALBESA, I

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY

Elsevier Science

Lugar: Switzerland; Año: 2004 vol. 76 p. 13 - 13

1011-1344

p class="abstract">Oxygen consumption by Staphylococcus aureus ATCC 29213 sensitive to ciprofloxacin was determined with an oxygen selective electrode. Increase in the O(2) consumption was observed with 0.45 micromL(-1) ciprofloxacin while higher concentrations gave rise to a reduction of O(2) consumption. Resistant S. aureus strain did not show increase of O(2) consumption in presence of ciprofloxacin. Nitro Blue Tetrazolium assay showed that production of reactive oxygen species (ROS) increased intracellularly in sensitive bacteria incubated with this antibiotic. The exposition to UV light (360 nm) augmented the intracellular oxidative stress of S. aureus and provoked increment of ROS in extracellular media. Generation of singlet oxygen O(2) ((1)Delta(g)) in S. aureus was measured by means of oxidation of methionine. The absorbance of methionine was monitored at 215 nm and a clear decrease was detected when sensitive S. aureus was stressed with ciprofloxacin. Sodium azide and 2,5-di