{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,23]],"date-time":"2026-06-23T23:28:16Z","timestamp":1782257296271,"version":"3.54.5"},"reference-count":41,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2020,7,28]],"date-time":"2020-07-28T00:00:00Z","timestamp":1595894400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100008530","name":"European Regional Development Fund","doi-asserted-by":"publisher","award":["KK.01.1.1.01.0001"],"award-info":[{"award-number":["KK.01.1.1.01.0001"]}],"id":[{"id":"10.13039\/501100008530","id-type":"DOI","asserted-by":"publisher"}]},{"name":"University of Rijeka","award":["17.12.2.1.01"],"award-info":[{"award-number":["17.12.2.1.01"]}]},{"name":"University of Rijeka","award":["uniri-prirod-18-173"],"award-info":[{"award-number":["uniri-prirod-18-173"]}]},{"name":"University of Rijeka","award":["uniri-biomed-18-171"],"award-info":[{"award-number":["uniri-biomed-18-171"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Legionella pneumophila is an environmental bacterium, an opportunistic premise plumbing pathogen that causes the Legionnaires\u2019 disease. L. pneumophila presents a serious health hazard in building water systems, due to its high resistance to standard water disinfection methods. Our aim was to study the use of photodynamic inactivation (PDI) against Legionella. We investigated and compared the photobactericidal potential of five cationic dyes. We tested toluidine blue (TBO) and methylene blue (MB), and three 3-N-methylpyridylporphyrins, one tetra-cationic and two tri-cationic, one with a short (CH3) and the other with a long (C17H35) alkyl chain, against L. pneumophila in tap water and after irradiation with violet light. All tested dyes demonstrated a certain dark toxicity against L. pneumophila; porphyrins with lower minimal effective concentration (MEC) values than TBO and MB. Nanomolar MEC values, significantly lower than with TBO and MB, were obtained with all three porphyrins in PDI experiments, with amphiphilic porphyrin demonstrating the highest PDI activity. All tested dyes showed increasing PDI with longer irradiation (0\u2013108 J\/cm2), especially the two hydrophilic porphyrins. All three porphyrins caused significant changes in cell membrane permeability after irradiation and L. pneumophila, co-cultivated with Acanthamoeba castellanii after treatment with all three porphyrins and irradiation, did not recover in amoeba. We believe our results indicate the considerable potential of cationic porphyrins as effective anti-Legionella agents.<\/jats:p>","DOI":"10.3390\/ijms21155367","type":"journal-article","created":{"date-parts":[[2020,7,29]],"date-time":"2020-07-29T07:31:45Z","timestamp":1596007905000},"page":"5367","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Cationic Porphyrins as Effective Agents in Photodynamic Inactivation of Opportunistic Plumbing Pathogen Legionella pneumophila"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6263-2404","authenticated-orcid":false,"given":"Andrija","family":"Lesar","sequence":"first","affiliation":[{"name":"Bioinstitut d.o.o., R. Steinera 7, 40000 \u010cakovec, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0661-2302","authenticated-orcid":false,"given":"Martina","family":"Mu\u0161kovi\u0107","sequence":"additional","affiliation":[{"name":"Department of Biotechnology, University of Rijeka, Radmile Matej\u010di\u0107 2, 51000 Rijeka, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gabrijela","family":"Begi\u0107","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, Bra\u0107e Branchetta 20, 51000 Rijeka, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7227-9969","authenticated-orcid":false,"given":"Martin","family":"Lon\u010dari\u0107","sequence":"additional","affiliation":[{"name":"Photonics and Quantum Optics Unit, Center of Excellence for Advanced Materials and Sensing Devices, Ru\u0111er Bo\u0161kovi\u0107 Institute, Bijeni\u010dka cesta 54, 10002 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7333-7611","authenticated-orcid":false,"given":"Dijana","family":"Tomi\u0107 Lin\u0161ak","sequence":"additional","affiliation":[{"name":"Department for Health Ecology, Faculty of Medicine, University of Rijeka, Bra\u0107e Branchetta 20, 51000 Rijeka, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6983-6576","authenticated-orcid":false,"given":"Nela","family":"Malatesti","sequence":"additional","affiliation":[{"name":"Department of Biotechnology, University of Rijeka, Radmile Matej\u010di\u0107 2, 51000 Rijeka, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8956-4675","authenticated-orcid":false,"given":"Ivana","family":"Gobin","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, Bra\u0107e Branchetta 20, 51000 Rijeka, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,7,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"373","DOI":"10.3390\/pathogens4020373","article-title":"Opportunistic Premise Plumbing Pathogens: Increasingly Important Pathogens in Drinking Water","volume":"4","author":"Falkinham","year":"2015","journal-title":"Pathogens"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"749","DOI":"10.1289\/ehp.1408692","article-title":"Epidemiology and Ecology of Opportunistic Premise Plumbing Pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa","volume":"123","author":"Falkinham","year":"2015","journal-title":"Environ. 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