# P-765. Bactericidal activity of peracetic acid against common uropathogens: a potential bladder irrigant for self-catheterizing patients or those with indwelling catheters

## TL;DR

Peracetic acid at low concentrations effectively kills bacteria causing urinary tract infections, suggesting it could be a safe bladder irrigant for catheter users.

## Contribution

Demonstrates peracetic acid's bactericidal efficacy against uropathogens at concentrations lower than those used in food applications.

## Key findings

- Peracetic acid killed all planktonic and biofilm bacteria at 50 ug/ml within 5 minutes.
- Minimum bactericidal concentrations for Enterobacterales were under 25 ug/ml.
- Rapid killing was observed, even at low concentrations.

## Abstract

The presence of an indwelling urinary catheter and regular self-catheterization are highly associated with bacteriuria and the potential for clinically significant infection. Various irrigating solutions have been tried to prevent bacteriuria in such cases, with limited success. Peracetic acid (PA) is approved by the FDA for application to food products at 200 ug/mL. Use of this drug has not been reported for use in humans.

Forty-four bacterial isolates from infected urine and 4 ATCC isolates were studied (see Table). Planktonic bacteria were studied after growth overnight in Mueller Hinton broth (MHB) at 37 C. Bacteria were added to serial dilutions of PA (3 to 150 ug/ml) to yield 2x106 (Gram positive cocci) to 2x107 (Gram negative rods) cfu/ml. Bacteria were quantitated after incubation at room temperature for 30 minutes. Biofilm was made by incubating bacteria in MHB in a gently swirling water bath at 37 C for 72 hr. Tubes were gently rinsed, and PA was added. Tubes were scraped with a ‘rubber policeman’ and bacteria were quantitated as above.

With 30 min exposure to PA, the MBC of all planktonic Enterobacterales was < 25 ug/ml, and the MBC90 of planktonic Pseudomonas and enterococci was < 25 ug/ml, with MBC of all strains < 50 ug/ml. Time-kill experiments showed that killing was extremely rapid. Because, in vivo, urine production would reduce concentration of PA, we studied killing by PA in a subset of 21 organisms after 5 min exposure to the same range of concentrations. MBC90 for Enterobacterales was < 25 ug/ml. Importantly, all organisms studied, whether planktonic or in biofilm state, were killed at 50 ug/ml.

PA, at concentrations well below those that are sprayed on food products, was bactericidal for 48 organisms that cause UTI. This compound has not been used in human studies. In the absence of substances that safely and effectively suppress bacteriuria in patients who self-catheterize or have indwelling urinary catheters PA deserves consideration for future clinical trials.

Donald P. Griffith, MD, None: Patent on peracetic acid + witch hazel is pending