Effect of a siliconized latex urinary catheter on bacterial adherence and human neutrophil activity

The effect of a siliconized latex urinary catheter on the in vitro adherence and growth of Pseudomonas aeruginosa and Escherichia coli and on the activity of human polymorphonuclear leukocytes (PMNs) was assessed. The adherence of P. aeruginosa to latex catheters was significantly greater than that of E. coli, being 30 times higher at 6 hr of incubation. The survival of E. coli (10(8) CFU/ml) in phosphate-buffered saline (PBS) containing segments of siliconized latex catheters was lower than in the controls. This effect seems to be due to a toxic effect produced by substances eluted into the medium from the catheters, as the viability of E. coli (10(3) CFU/ml) in eluates obtained from the incubation of catheters in PBS (24 hr; 37 degrees C) was significantly lower than in the controls. These phenomena were not observed with P. aeruginosa. The incubation of human PMNs with either catheter segments or eluates did not affect the uptake of opsonized E. coli but significantly decreased the production of superoxide radicals by these phagocytes. It is concluded that the adherence of P. aeruginosa to these catheters is higher than that of E. coli and that the latex urinary catheter used herein elutes substances that are in vitro toxic for E. coli and the oxygen-dependent bactericidal mechanisms of human PMNs.