Effects of antibiotics on adherence of Pseudomonas aeruginosa and Pseudomonas fluorescens to human fibronectin

Abstract

The effect of subminimal inhibitory concentration (1/2 MIC) of antimicrobial agents on the adherence of fluorescent Pseudomonas to human fibronectin (FN) was investigated by examining two Pseudomonas fluorescens and four Pseudomonas aeruginosa strains. The Escherichia coli (MC1061 and JM109) strains, used as negative controls, adhered poorly to FN immobilized on microtiter wells (adherence indices of 0.04 +/- 0.02 and 0.03 +/- 0.01 10(5) CFU/well, respectively). Two P. aeruginosa strains (NK125502 and ER82483) were highly adherent to FN (adherence indices of 3.22 +/- 0.75 10(5) and 3.08 +/- 1.42 10(5) CFU/well, respectively), the two others (ER98513 and ER92581) adhered less efficiently (adherence indices of 0.91 +/- 0.05 10(5) and 0.45 +/- 0.23 10(5) CFU/well, respectively). The two P. fluorescens strains (MF0 and ER74508) were highly adherent to fibronectin (adherence indices of 7.06 +/- 1.00 10(5) and 2.08 +/- 0.67 10(5) CFU/well, respectively). Cefsulodin was the only antimicrobial agent tested that decreased the FN adherence of the majority of the strains: decrease in adherence highly significant (p < 0.01) for the P. fluorescens MF0 strain, significant (p < 0.05) for the P. aeruginosa NK125502, ER98513 and the P. fluorescens ER74508 strains, and not significant for the P. aeruginosa ER92581 strain. The effects of chloramphenicol and polymyxin B on the adherence of Pseudomonas were strain dependent. Gentamicin had no statistically significant effect on bacterial adherence. We conclude that, in addition to its antibacterial activity, cefsulodin could be effective in preventing the adherence of fluorescent Pseudomonas to FN, an important property in the presence of injured epithelium and coated biomaterials.