AUTHOR=Hayashi Katsuhiko , Fukushima Aiko , Hayashi-Nishino Mitsuko , Nishino Kunihiko 

TITLE=Effect of methylglyoxal on multidrug-resistant Pseudomonas aeruginosa

JOURNAL=Frontiers in Microbiology

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2014.00180

DOI=10.3389/fmicb.2014.00180

ISSN=1664-302X

ABSTRACT=<p>Honey has a complex chemistry, and its broad-spectrum antimicrobial activity varies with floral source, climate, and harvesting conditions. Methylglyoxal was identified as the dominant antibacterial component of manuka honey. Although it has been known that methylglyoxal has antibacterial activity against gram-positive bacteria, including methicillin-resistant <italic>Staphylococcus aureus</italic> and vancomycin-resistant <italic>Enterococcus</italic>, there is not much information describing its activity against gram-negative bacteria. In this study, we report the effect of methylglyoxal against multidrug-resistant <italic>Pseudomonas aeruginosa</italic> (MDRP) using 53 clinically isolated strains. We also assessed the effect of deleting the five multidrug efflux systems in <italic>P. aeruginosa</italic>, as well as the efflux systems in <italic>Escherichia coli</italic> and <italic>Salmonella enterica</italic> serovar Typhimurium, on MICs of methylglyoxal. Our results indicate that methylglyoxal inhibits the growth of MDRP at concentrations of 128–512 μg/ml (1.7–7.1 mM) and is not recognized by drug efflux systems.</p>