Citation: Al-Qahtani, Manaf, et al. “Efficacy of anti-microbial catheters in preventing catheter associated urinary tract infections in hospitalized patients: A review on recent updates.” Journal of infection and public health 12.6 (2019): 760-766

Link: https://www.sciencedirect.com/science/article/pii/S1876034119303090

PDF

Article Summary:

This article is a review of antimicrobial urinary catheters used in hospitalized patients and their effectiveness in preventing catheter-associated urinary tract infections (CAUTIs). I chose this article because of a patient I saw with a PA that was admitted for syncope, likely secondary to a urinary tract infection who had a foley catheter in place (H&P #3). While he did not get the UTI while in the hospital with a catheter, he did have a CAUTI. I therefore chose this article because of the importance of addressing CAUTIs and because it was recently published in 2019. I also decided to read and summarize this article because I was interested in learning about what can be done to prevent them.

The article first addressed different types of catheters available for use. There are single-use external catheters, short term catheters (less than 28 days) and long-term catheters such as Foley catheters. Next it addressed the CDC’s criteria for CAUTI. For a UTI to be considered a CAUTI, the indwelling catheter must be in place for more than two days, the patient must have a least one symptom and the urine culture should grow no more than two organisms, with at least one bacteria more than 100,000 CFU/mL. As is known in a patient with an indwelling catheter, the urine collected is often “dirty” and can come back with a positive culture. In the setting of the patient I saw, who was treated for a urinary tract infection and who was believed to have syncope secondary to a UTI, it is still questionable as to whether it is a true UTI, considering the patient did not have any symptoms.

Urinary catheters are equipped with antimicrobial agents to prevent the colonization microbes. The agents work either by releasing antimicrobial agents, preventing adherence of microbes to the surface of the catheter, directly killing microbes by contact, or disrupting the biofilm formed. One of the most used antimicrobials is silver, which is coated internally and externally on catheters. According to this review, silver oxide has been shown to be effective against gram positive and gram-negative organisms and found a 3.7-fold reduction in CAUTIs in short term catherizations with a silver alloy. Other studies have also found a reduction in CAUTIs in catheters that use silver. While silver may not be as effective in long-term catherization, it does offer broad-spectrum coverage and is low in cost. Antibiotic coatings are another possible way to reduce CAUTIs, as the antibiotics are impregnated onto the catheter to prevent biofilm formation. One example discussed in the article is nitrofurazone, which also inhibits both gram positive and gram-negative bacteria, and has been shown to reduce bacteriuria and fungiuria, with an incidence of CAUTI of 13.8 in nitrofurazone group and 38.6 in the standard catheter group. One study evaluated combinations of antimicrobials and found that catheters coated with Rifampicin, sparfloxacin and triclosan were able to prevent colonization of Proteus mirabilis, E. coli and S. aureus for 7-12 weeks in comparison to commercial antimicrobial catheters that only prevented for 1-3 days.

While there are concerns for antimicrobial coated catheters, especially the development of resistance, it is apparent that these coated catheters, along with the silver coated catheters, do decrease the incidence in CAUTIs. Further studies into the cytotoxicity of these agents, long-term effects on catheter patients, microbial resistance and side effects are needed. With more trials and further investigation into coating agents for catheters, hopefully there will be a decrease in CAUTIs in the years to come.