Biofilms are dangerous colonies of bacteria forming inside medical devices, especially catheters. “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.”1
Urinary Tract Infections are the most common infections caused by biofilms. “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.”2
The Evolution of Catheters
“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
How to Prevent Bacteria Films
“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
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.
“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
New Catheter Design that Fights Biofilms
“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
However, scientists have developed a clever catheter design to prevent biofilms from interrupting healthy catheterizations. The new catheter uses a separate channel parallel to the drainage area. The specialist can inflate it with saline solutions or air. This causes the drainage area to stretch and deform, forcing the lodged biofilm out of position.
A team of Duke University scientists is in trial phases of a new catheter that is able to eliminate bacterial biofilms inside the drain tube. “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
Bacterial colonies produce this biofilm to protect themselves from outside forces, sort of like a town carapace. Introducing air or saline into the channel that runs parallel to it, and thus deforming the inner wall where the biofilm grows, the bacterial town carapace shakes, breaks and/or gets compromised. When urine flows through, it is flushed along with the urine.
“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
Before this breakthrough approach, most manufacturers focused on creating anti-bacterial films to fight the bacterial wall, with minor success. Catheter-induced urinary tract infections are still the number one hospital-acquired infections in the United States. The aforementioned mechanical way to eliminate these bacterial biofilms is much more effective, and bacteria cannot develop a defense. Additionally, patients who self-catheterize will probably be able to perform this at home.
Bacteria Film Infection Risk and Treatment
The high risk of contracting a urinary tract infection due to the solidification of biofilms is the basis for the creation of this bacterial biofilm-destroying catheter. These bacterial coatings cause complications to the healthcare practitioner and patients, especially if they are disabled or elderly.
“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 scientific community has dedicated several funds and researching to developing bacteria-fighting throughout the years. Not to mention the post-infection healthcare costs, particularly in recurring cases of UTI.
Before this catheter, patients and healthcare practitioners had to replace the catheter due to the blockages derived from the accumulation of bacterial biofilm layers. Interrupting this accumulation of bacteria reduces catheter-induced urinary tract infections and provides comfort, safety, assurance and a higher quality of life to patients who require catheterizations for their particular condition.
“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
However, the biofilm-breaking catheter is not finished, it is still under development since bacteria still grows in microscopic crevices or imperfections along the catheter. Currently, the scientific community aims to create a catheter with several inflation chambers to segregate and dislodge biofilm throughout the catheter walls.
“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 in respect to mucosal biocompatibility and effectiveness in reducing bacterial biofilm attachment.”11
The medical community expects that upcoming biomaterial will ultimately decrease bacterial adherence and biofilm accumulation to lower the rate of catheter-associated infection.
(1, 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
(2, 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
(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/