Formation of hydroxyl radicals contributes to the bactericidal activity of ciprofloxacin against Pseudomonas aeruginosa biofilms. Issue 3 (10th February 2014)

• Record Type: Journal Article
• Authors: Jensen, Peter Ø.; Briales, Alejandra; Brochmann, Rikke P.; Wang, Hengzhuang; Kragh, Kasper N.; Kolpen, Mette; Hempel, Casper; Bjarnsholt, Thomas; Høiby, Niels; Ciofu, Oana
• Is Part Of: Pathogens and disease. Volume 70:Issue 3(2014:Apr.)
• Page Start: 440
• Page End: 443
• Publication Date: 2014-02-10
• Subjects: Medical microbiology -- Periodicals; Pathogenic microorganisms -- Periodicals; Communicable diseases -- Microbiology -- Periodicals; Communicable diseases -- Pathogenesis -- Periodicals; Host-parasite relationships -- Periodicals; Systems biology -- Periodicals; 616.904105
• DOI: 10.1111/2049-632X.12120
• Languages: English
• ISSNs: 2049-632X

Abstract

<abstract abstract-type="main" id="fim12120-abs-0001"> <title>Abstract</title> <p>Antibiotic‐tolerant, biofilm‐forming <italic>Pseudomonas aeruginosa</italic> has long been recognized as a major cause of chronic lung infections of cystic fibrosis patients. The mechanisms involved in the activity of antibiotics on biofilm are not completely clear. We have investigated whether the proposed induction of cytotoxic hydroxyl radicals (OH<bold>˙</bold>) during antibiotic treatment of planktonically grown cells may contribute to action of the commonly used antibiotic ciprofloxacin on <italic>P. aeruginosa</italic> biofilms. For this purpose, WT PAO1, a catalase deficient Δ<italic>katA</italic> and a ciprofloxacin resistant mutant of PAO1 (<italic>gyrA</italic>), were grown as biofilms in microtiter plates and treated with ciprofloxacin. Formation of OH<bold>˙</bold> and total amount of reactive oxygen species (ROS) was measured and viability was estimated. Formation of OH<bold>˙</bold> and total ROS in PAO1 biofilms treated with ciprofloxacin was shown but higher levels were measured in Δ<italic>katA</italic> biofilms, and no ROS production was seen in the <italic>gyrA</italic> biofilms. Treatment with ciprofloxacin decreased the viability of PAO1 and Δ<italic>katA</italic> biofilms but not of <italic>gyrA</italic> biofilms. Addition of thiourea, a OH<bold>˙</bold> scavenger, decreased the OH<bold>˙</bold> levels and killing of PAO1 biofilm. Our study shows that OH<bold>˙</bold> is produced by <italic>P. aeruginosa</italic> biofilms treated with ciprofloxacin, which may contribute to the killing of biofilm subpopulations.</p> </abstract>