[Effect of cefepime on adhesion and phagocytosis of Pseudomonas aeruginosa]. / Efecto de cefepima en la adherencia y fagocitosis de Pseudomonas aeruginosa.

ABSTRACT

BACKGROUND: We studied the effect of subinhibitory concentrations of cefepime on cell surface hydrophobicity expression and adherence to epithelial cells of Pseudomonas aeruginosa. We also evaluated the effect of this drug on the interaction between Pseudomonas aeruginosa and human polymorphonuclear leukocytes. METHODS: The bacterial cell surface hydrophobicity was tested on a biphasic system (water/p-xylene). The bacterial adherence to epithelial cells as well as the phagocytosis of Pseudomonas aeruginosa was studied using radiometric techniques. The superoxide production was evaluated by means of cytochrome C reduction method. RESULTS: Pre-incubation of a non mucoid Pseudomonas aeruginosa strain with a 0.25 MIC value of cefepime produces a reduction in the adherence of this microorganism to epithelial cells, but without modifying the surface hydrophobicity. Pre-incubation of a mucoid and a non mucoid P. aeruginosa strain with a 0.25 MIC value of cefepime reduces its phagocytosis by polymorphonuclear leukocytes. The preincubation polymorphonuclear leukocytes with cefepime (1, 10, and 100 mg/ml) did not influence the phagocytosis of Pseudomonas aeruginosa nor the bactericidal mechanisms of PMN (superoxide production). At therapeutic concentrations, cefepime showed intracellular activity against P. aeruginosa in human polymorphonuclear leukocytes. CONCLUSIONS: The incubation of Pseudomonas aeruginosa with sub-MIC inhibit its adherence to epithelial cells and its intake by human polymorphonuclear leukocytes. At therapeutic concentrations, cefepime did not affect the bactericidal mechanisms of polymorphonuclear leukocytes, and shows a significant intracellular activity against P. aeruginosa.