{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T17:30:37Z","timestamp":1775583037793,"version":"3.50.1"},"reference-count":23,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,5,31]],"date-time":"2021-05-31T00:00:00Z","timestamp":1622419200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science","doi-asserted-by":"publisher","award":["19K07547"],"award-info":[{"award-number":["19K07547"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Network Joint Research Center for Materials and Devices","award":["20214041"],"award-info":[{"award-number":["20214041"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Multidrug-resistant Pseudomonas aeruginosa poses a serious problem due to hospital- and healthcare-associated infections. A major drug resistance mechanism of P. aeruginosa involves active efflux via resistance nodulation cell division (RND)-type multidrug efflux pumps of which MexXY is increasingly recognized as a primary determinant of aminoglycoside resistance in P. aeruginosa. MexXY overexpression is often observed in drug-resistant P. aeruginosa clinical isolates. MexXY deficiency increased pyoverdine production in all four P. aeruginosa strains we tested. MexXY-overproducing multidrug-resistant P. aeruginosa PA7 exhibited the greatest effect among the strains. Complementation with a MexXY-expressing plasmid restored low-level pyoverdine production in a MexXY-deficient P. aeruginosa mutant from PA7, indicating that MexXY expression decreases pyoverdine production. Because P. aeruginosa produces pyoverdine to acquire iron, MexXY-deficient mutants might be more susceptible to iron deficiency than MexXY-producing strains or might require extra iron. High-risk clones of multidrug-resistant P. aeruginosa reportedly tend to be MexXY overproducers but defective pyoverdine producers. This study suggests that P. aeruginosa reduces production of a virulence factor after acquiring a drug resistance factor.<\/jats:p>","DOI":"10.3390\/antibiotics10060658","type":"journal-article","created":{"date-parts":[[2021,5,31]],"date-time":"2021-05-31T21:42:06Z","timestamp":1622497326000},"page":"658","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Overexpression of the MexXY Multidrug Efflux System Correlates with Deficient Pyoverdine Production in Pseudomonas aeruginosa"],"prefix":"10.3390","volume":"10","author":[{"given":"Kei","family":"Ikarashi","sequence":"first","affiliation":[{"name":"Department of Infection Control Science, Meiji Pharmaceutical University, Tokyo 204-8588, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ryo","family":"Kutsuna","sequence":"additional","affiliation":[{"name":"Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Aichi 464-8650, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Junko","family":"Tomida","sequence":"additional","affiliation":[{"name":"Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Aichi 464-8650, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoshiaki","family":"Kawamura","sequence":"additional","affiliation":[{"name":"Department of Microbiology, School of Pharmacy, Aichi Gakuin University, Aichi 464-8650, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1371-8591","authenticated-orcid":false,"given":"Yuji","family":"Morita","sequence":"additional","affiliation":[{"name":"Department of Infection Control Science, Meiji Pharmaceutical University, Tokyo 204-8588, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,5,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1111\/2049-632X.12033","article-title":"Pseudomonas aeruginosa: New insights into pathogenesis and host defenses","volume":"67","author":"Gellatly","year":"2013","journal-title":"Pathog. 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