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A New Catheter that Fights Bacteria Films

“More than 75% of hospital-acquired or nosocomial urinary tract infections are initiated by urinary catheters, which are used during the treatment of 15–25% of hospitalized patients. Among other purposes, urinary catheters are primarily used for draining urine after surgeries and for urinary incontinence. During catheter-associated urinary tract infections, bacteria travel up to the bladder and cause infection. A major cause of catheter-associated urinary tract infection is attributed to the use of non-ideal materials in the fabrication of urinary catheters. Such materials allow for the colonization of microorganisms, leading to bacteriuria and infection, depending on the severity of symptoms. The ideal urinary catheter is made out of materials that are biocompatible, antimicrobial, and antifouling.”1

“About 95% of urinary tract infections (UTIs) are associated with the use of a urinary catheter, with an average cost of treatment of $44,043 for each hospital stay from CAUTI and a negative impact on patient recovery and quality of life.”2

“Urinary catheters have been used since the third century B.C., by the Greeks, Egyptians, and Chinese, but the first malleable urinary catheter on record was only made in 1779 by a goldsmith, Bernard. Some of the first materials used to make urinary catheters were copper, tin, bronze, gold, lead, papyrus, onion stems, dried reeds, and palm leaves. In recent times, materials such as gum-elastic, plastic (polyvinyl chloride, PVC), polyurethanes, silicone and latex rubbers have been used for their superior malleability. These materials have been developed over the years to include most of the characteristics desirable in a catheter: high tensile strength, soft and pliable, inherently chemical resistant, biocompatible and able to meet flow requirements while maintaining a minimally invasive circumference or French profile.”3

“The current approach for preventing catheter-associated infections has been either systemic antibiotic prophylaxis or antimicrobial coating of the device surface to reduce the concentration of bacteria. While antimicrobial agents can suppress UTI temporarily (for only days), colonization and infection of the urinary tract with resistant bacteria will eventually occur. Once a biofilm forms, the biofilm-embedded bacteria become protected from antimicrobial agents. In fact, when treated with antibiotics, these biofilms are not fully eradicated and begin to harbor antibiotic-resistant bacteria, which may compromise the effectiveness of these agents for even non biofilm-mediated infections.”4

“For the millions of people forced to rely on a plastic tube to eliminate their urine, developing an infection is nearly a 100 percent guarantee after just four weeks. But with the help of a little bubble-blowing, biomedical engineers hope to bring relief to urethras everywhere.”5

A team of Duke University scientists is in trial phases of a new catheter that is able to eliminate bacterial biofilms found inside the drain tube of catheters.

“About half of the time, the interior of long-term urinary catheters become plagued by biofilms, structures formed by colonies of bacteria that are extremely difficult to kill. Once established, it is only a matter of time before the biofilm becomes a welcoming host for other, more dangerous bacteria or begins to choke urine drainage, causing leakage, or even trauma to the patient’s body.”6

Patients currently using indwelling catheters oftentimes encounter blockage issues from these bacterial biofilms, as well as a propensity to acquire a urinary tract infection because these bacteria can make their way into the urinary tract.

However, an astute catheter design has been developed in order to prevent these biofilms from interrupting healthy catheterizations. This new catheter utilizes a separate channel that goes parallel to the drainage area and can be inflated with saline solutions or with air. This causes the drainage area to stretch and deform, forcing the lodged biofilm out of position.

“Duke University engineers have developed a new urinary catheter design that can eliminate nearly all of the hard-to-kill biofilm from the catheter walls. Instead of focusing on expensive antibacterial coatings, the researchers use physical deformation to knock the infectious film from its moorings.”7

“The biofilm mode of growth has been implicated in the majority of human bacterial infections. In the urinary tract, notable biofilm-associated infections include prostatitis, chronic cystitis, struvite urolithiasis, and catheter-associated infections.”8

Bacterial colonies produce this biofilm in order to protect themselves from outside forces, sort of like a town carapace. By introducing air or saline into the channel that runs parallel to it, and thus deforming the inner wall where the biofilm is located, the bacterial town carapace is shaken, broken and/or otherwise highly compromised. When urine flows through, it is then simply flushed along with the urine.

Before this breakthrough approach, most manufacturers were more focused on creating anti-bacterial films in order to fight the bacterial wall with very little success. Catheter-induced urinary tract infections are still the number one hospital-acquired infections in the United States today. The aforementioned mechanical way of getting rid of these bacterial biofilms is much more effective and bacteria have no chance at developing a defense to this anytime soon. What’s more, patients who self-catheterize will most likely be able to perform this at home.

“Because treatment of asymptomatic bacteriuria in adults is generally unlikely to confer clinical benefit, antibiotics are recommended only for pregnant women and for individuals who are about to undergo urological procedures. Indeed, treatment of asymptomatic bacteriuria in diabetic women was found to incur harm, because the treated group had a higher incidence of adverse antimicrobial reactions yet had the same incidence of symptomatic UTI as did the untreated group.”9

The high risk of contracting a urinary tract infection due to the solidification of biofilms that buildup in indwelling is the basis for the creation of this bacterial biofilm-destroying catheter.  These bacterial coatings have always presented complicated problems to not only the healthcare practitioner but obviously for the patient as well, especially if advanced in years or disabled.

Benefits of Catheters that fight Bacteria Films

The amount of funds that have gone into researching and developing bacteria-fighting catheters has been astounding throughout the years. Not to mention the healthcare cost of the patient post-infection, particularly the recurring urinary tract infection sufferers. For the most part, before this new catheter, patients and healthcare practitioners had to simply replace the catheter due to the blockages as a result of the accumulation of bacterial biofilm layers.

By interrupting this accumulation of bacteria, catheter-induced urinary tract infections can be reduced to an irregular occurrence and provide comfort, safety, assurance and overall higher quality of life to patients who require catheterizations for their particular condition.

However, the biofilm-breaking catheter is not a completely finished product and is still being developed since bacteria can still be present in microscopic crevices or imperfections along the catheter. Currently, the focus has been on creating a catheter with several inflation chambers so as to more effectively segregate and dislodge biofilm throughout the entirety of catheter walls.

“Biofilm removal from biomaterials is of fundamental importance and is especially relevant when considering the problematic and deleterious impact of biofilm infections on the inner surfaces of urinary catheters. Catheter-associated urinary tract infections are the most common cause of hospital-acquired infections and there are over 30 million Foley urinary catheters used annually in the USA.”10

“It is hoped that further advances in medical technology will allow modification of catheterization procedures, duration and need for catheterization, and provide improvements in the design of catheter urinary drainage systems. Studies have demonstrated that the internal luminal route of catheter-associated infections can be almost completely negated, at least for a short time, by the use of a strictly maintained sterile closed drainage system, with the possible addition of a bacterial barrier or hurdle.

The design of such a device or mechanism to stop the periurethral route would be very helpful. Biomaterial research is an exploding new science, and research must continue with these new materials with respect to mucosal biocompatibility and effectiveness in reducing bacterial biofilm attachment. It is anticipated that new biomaterials will eventually reduce bacterial adherence and biofilm formation and subsequently decrease the rate of catheter-associated infection.”11

 

References

(1, 3) A Review of the Recent Advances in Antimicrobial Coatings for Urinary Catheters. Singha, P., Locklin, J., & Handa, H. Acta Biomaterialia. 2017. https://www.sciencedirect.com/science/article/pii/S1742706116306663?via%3Dihub

(2, 4) Micropatterned Surfaces for Reducing the Risk of Catheter-Associated Urinary Tract Infection. Reddy, S., Chung, K., McDaniel, C., Darouiche, R., Landman, J., & Brennan, A. Journal of Endourology. 2011. https://pdfs.semanticscholar.org/a9ae/6b4ed331f43e8eea7ae36810cf8159c6b910.pdf

(5, 6, 7) Catheter Innovation Destroys Dangerous Biofilms. Kingery, K. Duke University: Pratt School of Engineering. 2014. https://pratt.duke.edu/about/news/catheter-innovation-destroys-dangerous-biofilms

(8) The Development Of Bacterial Biofilm on Indwelling Catheters. Morris, N., Stickler, D., & McLean, R. World Journal of Urology. 1999. https://www.researchgate.net/publication/12661127_The_development_of_bacterial_biofilms_on_indwelling_catheters

(9) Inappropriate Treatment of Catheter-Associated Asymptomatic Bacteriuria in a Tertiary Care Hospital. Trautner, B., Cope, M., Cevallos, M., Cadle, R., Darouiche, R., & Musher, D. Clinical Infectious Disease. 2009. https://academic.oup.com/cid/article/48/9/1182/407035

(10) Urinary catheter capable of repeated on-demand removal of infectious biofilms via active deformation. Levering, V., Cao, C., Shivapooja, P., Levinson, H., Zhao, X., & López, Gabriel. Biomaterials. 2016. https://www.sciencedirect.com/science/article/pii/S0142961215008807?via%3Dihub

(11) Bacterial biofilms and catheters: A key to understanding bacterial strategies in catheter-associated urinary tract infection. Nickel, J., & Costerton, J. The Canadian Journal of Infectious Diseases. 1992. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3298070/

 

María Laura Márquez
13 October, 2018

Written by

María Laura Márquez, general doctor graduated from The University of Oriente in 2018, Venezuela. My interests in the world of medicine and science, are focused on surgery and its breakthroughs. Nowadays I practice my profession...read more:

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