# Synergistic effect of electrolyzed oxidized water (EO) and peroxyacetic acid on plasmid-mediated quinolone resistance genes of Pseudomonas aeruginosa

## TL;DR

This study shows that combining electrolyzed oxidized water and peroxyacetic acid effectively reduces Pseudomonas aeruginosa biofilms and quinolone resistance gene expression.

## Contribution

The novel finding is the synergistic effect of EOW and PAA on reducing PMQR gene expression in P. aeruginosa biofilms.

## Key findings

- 80% of confirmed isolates contained plasmid qnr genes, indicating widespread quinolone resistance.
- The EOW-PAA combination significantly reduced biofilm and quinolone-resistant gene expression within 20 minutes.
- PAA and EOW together show strong antibacterial activity and could help combat resistant bacterial infections.

## Abstract

Pseudomonas aeruginosa displays major biofilm formation, food spoilage, and significant losses for the food industry. It extremely exhibits inherent resistance to various antibiotics, including quinolones, which can spread via plasmids. The present study investigates the prevalence of biofilm-forming P. aeruginosa in meat products and assesses its antibiotic resistance patterns. Evaluating the effectiveness of electrolyzed-oxidized water (EOW) and per-acetic acid (PAA) alone or in a combination against P. aeruginosa biofilm formed on stainless steel (SS) surfaces. Besides, the effect on quinolone-resistance (qnr) gene expression level using real-time PCR. P. aeruginosa was isolated from 24.6% of the total tested samples (37/150), with a significant variation observed regarding the contamination levels of the tested products. 36.3% of the isolates demonstrated robust biofilm production, with 82.3% displaying multi-drug resistance (MDR). Isolates revealed complete susceptibility to amikacin (100%) and gentamycin (82%). Quinolone resistance was observed in 23% and 17% of the isolates for ciprofloxacin and levofloxacin, respectively. 80% (4/5) among the confirmed isolates were enclosed the plasmid qnr genes. The genes pslA and gyrA were detected in 40% and 60%, respectively. EOW, particularly when combined with PAA, reveals strong antibacterial activity against P. aeruginosa and greatly decreases its count. Moreover, it can eliminate its biofilm within 20 min of exposure and significantly decrease the expression levels of quinolone-resistant genes. In conclusion, PAA and EOW are effective agents for biofilm control on SS surfaces, particularly when used in combined form, and could be more effective in combating resistant bacterial infections and controlling the spread of PMQR.

The online version contains supplementary material available at 10.1007/s11274-025-04384-w.