Evaluation Of Antimicrobial Durability And Anti-Biofilm Effects In Urinary Catheters Against Enterococcus Faecalis Clinical Isolates And Reference Strains

Background: Enterococcus faecalis, Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa and Candida albicans biofilms are major causes of catheter-associated urinary tract infections. Antimicrobial-coated or impregnated urinary catheters are seen as a possible way to prevent these infections. Aims: To determine the biofilm-forming ability of 89 E. faecalis isolates from urinary tract infections and to compare several urinary catheters for antimicrobial durability and the inhibitory effects on biofilm formation of different laboratory strains and clinical isolates of E. faecalis. Study Design: In vitro experimental study. Methods: The biofilm forming ability of E. faecalis isolates was determined by the crystal violet staining and plate counting methods. For comparison of urinary catheters, biofilms of 45 E. faecalis isolates from the catheter samples of hospitalized patients and five laboratory strains of E. coli ATCC25922, S. epidermidis ATCC35984, P. aeruginosa ATCC27853, E. faecalis ATCC29212 and C. albicans ATCC90028 were formed on the catheters in 24-well tissue culture plates. Scanning electron microscopy analysis was performed to observe biofilms. Results: All 89 E. faecalis isolates were found to be biofilm positive. Nitrofurazone-impregnated catheters significantly reduced the cell counts of E. faecalis isolates and completely inhibited the formation of P. aeruginosa and S. epidermidis biofilms compared with the others. Regarding reduction of biofilm cell counts, a hydrophilic-coated catheter was more effective against P. aeruginosa, whereas a silver-coated catheter was found to be more effective against S. epidermidis. The nitrofurazone-impregnated catheter had the best antimicrobial durability. Conclusion: Urine isolates of E. faecalis had considerable ability with respect to biofilm formation. The nitrofurazone-impregnated catheter was the most effective against all tested bacteria; however, the effect of a hydrophilic or silver-coated catheter depends on the species present in it.PubMedWoSScopu

An Investigation of the Bactericidal Activity of Chlorhexidine Digluconate Against Multidrug-Resistant Hospital Isolates

Background/aim: Hospital infections are among the most prominent medical problems around the world. Using proper biocides in an appropriate way is critically important in overcoming this problem. Several reports have suggested that microorganisms may develop resistance or reduce their susceptibility to biocides, similar to the case with antibiotics. In this study we aimed to determine the antimicrobial activity of chlorhexidine digluconate against clinical isolates. Materials and methods: The susceptibility of 120 hospital isolated strains of 7 bacterial genera against chlorhexidine digluconate was determined by agar dilution test, using minimum inhibitory concentration (MIC) values and the EN 1040 Basic Bactericidal Activity Test to determine the bactericidal activity. According to MIC values, Pseudomonas aeruginosa and Stenotrophomonas maltophilia were found to be less susceptible to chlorhexidine digluconate. Results: Quantitative suspension test results showed that 4% chlorhexidine digluconate was effective against antibiotic resistant and susceptible bacteria after 5 min of contact time and can be safely used in our hospital. However, concentrations below 4% chlorhexidine digluconate caused a decrease in bactericidal activity, especially for Staphylococcus aureus and P. aeruginosa. Conclusion: It is crucial to use biocides at appropriate concentrations and to perform surveillance studies to trace resistance or low susceptibility patterns of S. aureus, P. aeruginosa, and other hospital isolates.WoSScopu