Evaluation of Antimicrobial Durability and Anti-Biofilm Effects in Urinary Catheters Against Enterococcus faecalis Clinical Isolates and Reference Strains

Abstract

Background: Enterococcus faecalis, Escherichiacoli, Staphylococcus epidermidis, Pseudomonasaeruginosa and Candida albicans biofilms are majorcauses of catheter-associated urinary tract infections.Antimicrobial-coated or impregnated urinary cathetersare seen as a possible way to prevent these infections.Aims: To determine the biofilm-forming ability of 89E. faecalis isolates from urinary tract infections andto compare several urinary catheters for antimicrobialdurability and the inhibitory effects on biofilm formationof different laboratory strains and clinical isolates of E.faecalis.Study Design: In vitro experimental study.Methods: The biofilm forming ability of E. faecalisisolates was determined by the crystal violet stainingand plate counting methods. For comparison of urinarycatheters, biofilms of 45 E. faecalis isolates from thecatheter samples of hospitalized patients and fivelaboratory strains of E. coli ATCC25922, S. epidermidisATCC35984, P. aeruginosa ATCC27853, E. faecalisATCC29212 and C. albicans ATCC90028 were formedon the catheters in 24-well tissue culture plates. Scanningelectron microscopy analysis was performed to observebiofilms.Results: All 89 E. faecalis isolates were found to bebiofilm positive. Nitrofurazone-impregnated catheterssignificantly reduced the cell counts of E. faecalisisolates and completely inhibited the formation of P.aeruginosa and S. epidermidis biofilms compared withthe others. Regarding reduction of biofilm cell counts,a hydrophilic-coated catheter was more effectiveagainst P. aeruginosa, whereas a silver-coated catheterwas found to be more effective against S. epidermidis.The nitrofurazone-impregnated catheter had the bestantimicrobial durability.Conclusion: Urine isolates of E. faecalis hadconsiderable ability with respect to biofilm formation.The nitrofurazone-impregnated catheter was the mosteffective against all tested bacteria; however, the effectof a hydrophilic or silver-coated catheter depends on thespecies present in it.