{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,2]],"date-time":"2026-11-02T23:08:07Z","timestamp":1793660887578,"version":"4.5.1"},"reference-count":42,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2025,8,5]],"date-time":"2025-08-05T00:00:00Z","timestamp":1754352000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Molteni Therapeutics SRL","award":["B14I20001570007"],"award-info":[{"award-number":["B14I20001570007"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The emergence and spread of antimicrobial resistance among pathogens are significantly reducing available therapeutic options, highlighting the urgent need for novel and complementary treatment strategies. Antimicrobial photodynamic therapy (aPDT) is a promising alternative approach that can overcome antimicrobial resistance through a multitarget mechanism of action, exerting direct bactericidal and fungicidal effects with minimal risk of resistance development. Although aPDT has shown efficacy against a variety of pathogens, data on its activity against large collections of clinical multidrug-resistant strains are still limited. In this study, we assessed the antimicrobial activity of the photosensitizer RLP068\/Cl combined with a red light-emitting LED source at 630 nm (Molteni Farmaceutici, Italy) against a large panel of Gram-negative and Gram-positive bacterial strains harboring relevant resistance traits and Candida species. Our results demonstrated the significant microbicidal activity of RLP068\/Cl against all of the tested strains regardless of their resistance phenotype, with particularly prominent activity against Gram-positive bacteria (range of bactericidal concentrations 0.05\u20130.1 \u00b5M), which required significantly lower exposure to photosensitizer compared to Candida and Gram-negative species (range 5\u201320 \u00b5M). Overall, these findings support the potential use of RLP068\/Cl-mediated aPDT as an effective therapeutic strategy for the management of localized infections caused by MDR organisms, particularly when conventional therapeutic options are limited.<\/jats:p>","DOI":"10.3390\/ijms26157545","type":"journal-article","created":{"date-parts":[[2025,8,6]],"date-time":"2025-08-06T07:45:11Z","timestamp":1754466311000},"page":"7545","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Antimicrobial Photodynamic Activity of the Zn(II) Phthalocyanine RLP068\/Cl Versus Antimicrobial-Resistant Priority Pathogens"],"prefix":"10.3390","volume":"26","author":[{"given":"Ilaria","family":"Baccani","sequence":"first","affiliation":[{"name":"Department of Experimental and Clinical Medicine (DMSC), University of Florence, Largo Brambilla, 3, 50134 Florence, FI, Italy"},{"name":"Microbiology and Virology Unit, Careggi University Hospital, Largo Brambilla, 3, 50134 Florence, FI, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sara","family":"Cuffari","sequence":"additional","affiliation":[{"name":"Department of Experimental and Clinical Medicine (DMSC), University of Florence, Largo Brambilla, 3, 50134 Florence, FI, Italy"},{"name":"Microbiology and Virology Unit, Careggi University Hospital, Largo Brambilla, 3, 50134 Florence, FI, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francesco","family":"Giuliani","sequence":"additional","affiliation":[{"name":"L. Molteni & C. dei Fratelli Alitti, Societ\u00e0 di esercizio S.P.A. SS57 Loc. granatieri, 50018 Scandicci, FI, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9386-0434","authenticated-orcid":false,"given":"Gian Maria","family":"Rossolini","sequence":"additional","affiliation":[{"name":"Department of Experimental and Clinical Medicine (DMSC), University of Florence, Largo Brambilla, 3, 50134 Florence, FI, Italy"},{"name":"Microbiology and Virology Unit, Careggi University Hospital, Largo Brambilla, 3, 50134 Florence, FI, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Simona","family":"Pollini","sequence":"additional","affiliation":[{"name":"Department of Experimental and Clinical Medicine (DMSC), University of Florence, Largo Brambilla, 3, 50134 Florence, FI, Italy"},{"name":"Microbiology and Virology Unit, Careggi University Hospital, Largo Brambilla, 3, 50134 Florence, FI, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"100947","DOI":"10.1016\/j.lanmic.2024.07.010","article-title":"Antimicrobial resistance: A concise update","volume":"6","author":"Ho","year":"2025","journal-title":"Lancet Microbe"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1007\/s40588-024-00219-8","article-title":"Emerging Antifungal Resistance in Fungal Pathogens","volume":"11","author":"Hui","year":"2024","journal-title":"Curr. 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