In vitro evaluation of E. coli and S. epidermidis adhesion on dressing materials used in hypospadias repair

Abstract

Background: An in vitro study was performed to evaluate the adherence of Escherichia coli and Staphylococcus epidermidis to different dressing materials. Methods: Hydrophyl gauze swab (GS), sterile flax swab (FS), and their nitrofurazone (Furacin®) absorbed forms (GSF and FSF), sterile paraffin-covered gauze with chlorhexidine acetate (0.5 %) (Bactigrass®, BG), and semipermeable transparent film gauze (Tegaderm®, TG) were used in the study. A 1 cm 2 of each material was placed in culture plates, and E. coli ATCC 25922 and S. epidermidis ATCC 12228 were suspended in each plate. After 24, 48 h, and 1 week of incubation period, colony counts were calculated in colony-forming units (CFU) per square centimeter unit. Bacterial adhesion was compared between groups, and each dressing material was also compared for different incubation periods (24, 48 h, and 1 week). Results: The colony counts were significantly decreased in GSF and FSF groups (Kruskal-Wallis test, p < 0.05). There was no difference for E. coli adhesion in GS, FS, BG, and TG groups (p > 0.05). The significant difference detected for S. epidermidis adhesion in the first 24 to 48 h could not be detected at the end of a 1-week period. There was no statistical difference in groups when compared for 24-, 48-h, and 1-week periods of incubations (Wilcoxon signed-rank test, p > 0.05). In BG group, E. coli adhesion was increased, and S. epidermidis adhesion was decreased without a significant difference at the end of a 1-week period (p > 0.05). Conclusions: Nitrofurazone absorbed sterile gauze materials have less bacterial adhesion. In vitro adhesion of E. coli and S. epidermidis did not differ between the 24-h and 1-week period. E. coli adhesion to BG can be increased if the duration of dressing prolonged up to a 1-week period.Level of Evidence: Not ratable. © 2013 Springer-Verlag Berlin Heidelberg.