Prophylactic efficacy of a new gentamicin-releasing urethral catheter in short-term catheterized rabbits

Objective To describe an indwelling urethral catheter coated with gentamici n sulphate on the inner and outer surface of the catheter, and to evaluate the efficacy and safety of this catheter in preventing catheter-associated infections in rabbits. Materials and methods Sixty rabbits were divided equally into control and e xperimental groups which were then subdivided equally according to the dura tion of catheterization (1, 3 and 5 days). Silicone-treated latex catheters were used in the control group and gentamicin-releasing catheters in the e xperimental group. Urine samples and surface swabs from the catheter were c ultured for bacteriological assessment, and the catheter surface examined b y scanning electron microscopy to structurally analyse the biofilms. Results The gentamicin-releasing catheter reduced the incidence of bacteriu ria (defined as greater than or equal to 100 c.f.u./mL) after both 3 and 5 days of catheterization (eight and 10 rabbits, respectively, for the contro l catheter, vs two and four rabbits for the gentamicin-releasing catheter, P < 0.05). The surfaces of the gentamicin-releasing catheter were colonized less often than those of the control catheter after both 3 and 5 days (eig ht and 10, respectively, for the control, vs one and four for the gentamici n-releasing catheter, P < 0.05). Scanning electron microscopy showed the fo rmation of bacterial biofilm throughout the 3-day and 5-day control cathete rs, but deterioration of the bacterial biofilm was visible on the surface o f the gentamicin-releasing catheters, Conclusion This new gentamicin-releasing catheter produced an antibacterial barrier which inhibited catheter-associated urinary tract infection with n o toxicity for at: least 5 days. These in vivo studies suggest that this ne w catheter may be useful for controlling infection, with systemic and local safety, in patients undergoing short-term indwelling urethral catheterizat ion.