Evaluation of the retrograde contamination guard in a bacteriologically challenged rabbit model.
ABSTRACT We compared a newly developed closed urinary drainage system incorporating a retrograde contamination guard (RCG) with the conventional closed drainage system. The new system contains a solid bactericide (povidone iodine) pellet enclosed in a porous cartridge at the drain port of the urine collection bag. A catheterised rabbit model was used. The urine drainage bags were challenged daily for 8 days with an auxotrophically marked uropathogenic strain of Escherichia coli at the outlet tube. The bag urine was infected with the marked organism in 10 of the 11 rabbits in the control group (conventional collection bags) in 3.8 +/- 1.03 days and in only 1 of the 13 rabbits fitted with the RCG. The RCG effectively prevents contamination of the urine drainage bag and thus may play an important role in reducing the incidence of nosocomial urinary tract infections.
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ABSTRACT: Despite major technological improvements in catheter drainage systems, the indwelling Foley catheter remains the most common cause of nosocomial infection in medical practice. By approaching this common complicated urinary tract infection from the perspective of the biofilm strategy bacteria appear to use to overcome obstacles to produce bacteriuria, one appreciates a new understanding of these infections. An adherent biofilm of bacteria in their secretory products ascends the luminal and external surface of the catheter and drainage system from a contaminated drainage spigot or urethral meatus into the bladder. If the intraluminal route of bacterial ascent is delayed by strict sterile closed drainage or addition of internal modifications to the system, the extraluminal or urethral route assumes greater importance in the development of bacteriuria, but takes significantly longer. Bacterial growth within these thick coherent biofilms confers a large measure of relative resistance to antibiotics even though the individual bacterium remains sensitive, thus accounting for the failure of antibiotic therapy. With disruption of the protective mucous layer of the bladder by mechanical irritation, the bacteria colonizing the catheter can adhere to the bladder's mucosal surface and cause infection. An appreciation of the role of bacterial biofilms in these infections should suggest future directions for research that may ultimately reduce the risk of catheter-associated infection.The Canadian journal of infectious diseases = Journal canadien des maladies infectieuses 09/1992; 3(5):261-7. · 0.76 Impact Factor
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ABSTRACT: Residual urethral defects after failed hypospadias surgery present difficulties in reconstruction. In these situations, repair using vascularized tissue flaps remains ideal, yet challenging. In order to offer more surgical alternatives in these cases, the use of vascularized tunica vaginalis flaps as urethral replacements has recently been established in an animal model. We undertook the following studies to further define the role of tunica vaginalis in urethral reconstruction. A vascularized flap of tunica vaginalis was used to replace an experimentally created 25-30 mm. gap in the anterior urethra of 26 rabbits, either as an onlay or tube flap. A control group consisting of 7 animals underwent only a segmental anterior urethral resection and primary re-anastomosis. Satisfactory urethral healing occurred in all control animals that survived the procedure. All 8 animals which had tunica vaginalis tube flap reconstruction underwent contracture of the neourethra probably secondary to the presence of striated cremasteric muscle elements brought with the tunica during mobilization. All 16 animals available for long term study in the onlay flap group had excellent flap viability and 100% urethral patency rates. The mesothelial lining of the tunica was seen to be replaced by a stratified epithelial lining similar to the urothelial lining of the native urethra. The tunica vaginalis is a viable alternative to other tissues presently used for urethral replacement and can be used successfully as a vascularized onlay flap.The Journal of Urology 05/1998; 159(5):1708-11. DOI:10.1097/00005392-199805000-00098 · 3.75 Impact Factor
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ABSTRACT: Rabbits are widely used as an animal model for urologic research studies in which urinary bladder catheterization is required. However, standard manual retrograde urinary catheterization proved to be difficult to perform on anesthetized male rabbits in a research study, with frequent misplacement of the catheter into the vesicular gland. Attempts to reposition the catheter into the bladder after initial entry into the vesicular gland frequently failed and resulted in exclusion of the animal from the study. We assessed the normal anatomy of the lower urinary tract of male rabbits to determine the cause of catheterization misdirection into the vesicular gland and to develop a more reliable technique for urinary bladder catheterization. A modified 'digital (finger) pressure' catheterization technique was developed for successful urinary catheterization of male rabbits. Retrospective statistical analysis of 45 rabbits used for urinary catheterization studies showed improvement in the success rate of catheterization by using the digital pressure technique over the standard method of retrograde urinary catheter insertion. In addition, we here review the relevant gross and histologic anatomy of the urogenital tract of male rabbits.Journal of the American Association for Laboratory Animal Science: JAALAS 01/2013; 52(2):180-5. · 0.73 Impact Factor