title: Reduction of virulence factor pyocyanin production in multidrug-resistant Pseudomonas aeruginosa.
abstract: Nosocomial infections caused by metallo-β-lactamase (MBL)-producing multidrug-resistant (MDR) Pseudomonas aeruginosa have become a worldwide problem. Pyocyanin, a representative pigment produced by P. aeruginosa, is the major virulence factor of this organismThe aim of this study was to investigate the pyocyanin-producing ability of MBL-producing MDR P. aeruginosa. A total of 50 clinical isolates of P. aeruginosa, including 20 MDR strains, were collected at 18 general hospitals in Japan. The chromaticity and luminosity produced by pyocyanin in each isolate were measured. The quantity of pyocyanin and the expression of the phzM and phzS genes coding a pyocyanin synthesis enzyme were measured. MDR strains showed a bright yellow-green, while non-MDR strains tended to show a dark blue-green. The quantities of pyocyanin in MBL-producing strains and non-producing strains were 0.015 ± 0.002 and 0.41 ± 0.10 μg, respectively. The expression of the phzM and phzS genes in the MDR strains was 11 and 14 %, respectively, of the expression in the non-MDR strains. When the MBL gene was transduced into P. aeruginosa and it acquired multidrug resistance, it was shown that the pyocyanin-producing ability decreased. The pathogenicity of MBL-producing MDR P. aeruginosa may be lower than that of non-MDR strains. These MBL-producing MDR strains may be less pathogenic than non-MDR strains. This may explain why MDR-P. aeruginosa is unlikely to cause infection but, rather, causes subclinical colonization only.
authors.affiliation: Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Fuse
authors.forename: Shigeru
authors.initials: S
authors.lastname: Fujimura
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kikuchi
authors.forename: Kazunori
authors.initials: K
authors.lastname: Gomi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Iida
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nukiwa
authors.forename: Akira
authors.initials: A
authors.lastname: Watanabe
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003428:Cross Infection / Q000382:microbiology; D015536:Down-Regulation; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D011710:Pyocyanine / Q000096:biosynthesis* / Q000494:pharmacology; D037521:Virulence Factors / Q000096:biosynthesis* / Q000494:pharmacology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D037521:Virulence Factors; D011710:Pyocyanine; D006899:Mixed Function Oxygenases; C439053:PhzS protein, Pseudomonas aeruginosa; D008780:Methyltransferases; C439052:PhzM protein, Pseudomonas aeruginosa; D001618:beta-Lactamases