How to Treat Biofilms on Catheters

Catheters are tubes made of latex or silicone that are used to assist in draining excess fluids and urine, and for the intravenous administration of medications, liquid nutrition or blood products. Bacteria find the conditions of the catheter and surrounding bodily tissue an ideal breeding ground. They come from the microflora (bacteria) on the skin of the patient and medical personnel, or contaminated substances that have been given intravenously. Bacteria attach to the outer or inner surface of the catheter and multiply, secreting a gel-like substance (biofilm) that protects the bacterial colony. The longer the catheter stays in place, the larger the biofilm development and the higher the risk of an individual developing an infection.

Instructions

• 1

  Replace the catheters on a routine basis. The bacteria in biofilms are hard to eradicate because they develop resistance to many of the antibiotics used to treat infections. Replacing the catheter before using antibiotics for treatment of infections reduces the time needed to get rid of the infection and leads to fewer relapses.

• 2

  Control the patient's urinary pH. Crystalline biofilms cause catheter encrustation that blocks urinary catheters in up to half of individuals with long-term catheterization. The blockages, and resulting infections, are primarily caused by bacteria that produce the enzyme urease that changes the urea in urine into ammonia. The ammonia raises the nucleation pH (pH n, the level at which crystals are formed) of the urine, causing the formation of crystals of calcium and magnesium salts that become trapped in the biofilm. Individuals with long-term catheterization rarely drink enough liquids, causing them to have low pH n. Consumption of liquids containing citrate, such as orange juice, and increasing overall fluid intake raises pH n and reduces the rate of crystal encrustation.

• 3

  Use sensors that change color as crystalline biofilms begin to form on the surface of the urinary catheter. These are placed in drainage bags and detect rising pH n to provide early warning before the encrustation blocks the tubing.

• 4

  Use catheters with manual valves. Continuously draining catheters become blocked by encrustation more quickly than catheters with a manual valve. Valves allow the individual to periodically drain the bag, or to forgo the need for a drainage bag altogether. Urine is not continually bathing the catheter resulting in rapid biofilm and crystal formation.

• 5

  Choose silicone catheters whenever possible. Catheter surfaces appear smooth but are actually rough and filled with craters that make cozy places for biofilms to multiply. Latex catheters have rougher surfaces than silicone catheters because of manufacturing methods and the use of a fine powder to prevent the latex from sticking to machinery during production. Silicone catheters are smoother, but still have some uneven surfaces, particularly at the openings (eyeholes), and from striation marks from extrusion (being pushed through an opening during manufacture, similar to pushing softened modeling clay through a ring).

• 6

  Choose catheter surfaces made of materials that are chemically hydrophilic (attracted to and easily dissolved in water). They are less likely to allow bacteria to stick to the tubing unless the pH n of urine increases (becomes more alkaline). Alkaline urine results in crystals that congregate on the surface and begin to form biofilm.

• 7

  Practice proper catheter management. Many healthcare professionals believe urinary tract infections are unavoidable and develop "catheter apathy." Nurses, the primary managers of catheters, can reduce the incidence of infections caused by biofilm on catheters simply by properly washing their hands. Properly attaching and securing the catheter to prevent movement also reduces biofilm colonization.

• 8

  Consider the use of catheters impregnated with antimicrobial substances, including silver. They have not conclusively shown a reduction in biofilm-related infections but might work in some situations.