A sustainable approach to control biofilms infections and reduce medical waste: Catheters coated with antibiotics inhibit single and dual-species biofilms

Catheter-Associated Urinary Tract Infections (CAUTIs) are one of the major diseases that cause severe illness and death among the wider population. More than 30,000 deaths are reported each year due to CAUTI. These infections are caused due to different biofilm- forming species such as Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Candida spp, Klebsiella spp, Proteus spp, Bacteroides spp, Staphylococcus aureus, and Enterobacter spp. This study examined the growth of two major uropathogenic (E. coli and E. faecalis) strains on catheter surfaces under antibiotic-treated and untreated conditions. The antibiotics used for this study are Ciprofloxacin and Doxycycline, which are considered to be broad-spectrum antibiotics. The Minimum Inhibitory Concentration (MIC) assay was performed to identify the concentration at which these antibiotics show efficient inhibition. The results show that both antibiotics have an inhibitory effect on single and dual-species biofilms. However, E. coli is more resistant to Doxycycline (MIC: 100 μg/mL), whereas E. faecalis is more resistant to Ciprofloxacin (MIC: 50 μg/mL). Interestingly, the dual-species cultures are more susceptible to both antibiotics at lower concentrations, 5μg/mL. Furthermore, a CFU assay was performed to quantify the results obtained, and a similar trend could be observed with around a 4-fold reduction in bacterial colonies when catheters are coated with antibiotics. In addition, the antibiotic-coated catheters contribute no pathogen contamination to the environment.