{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T04:47:46Z","timestamp":1791348466117,"version":"4.3.1"},"reference-count":41,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2021,9,4]],"date-time":"2021-09-04T00:00:00Z","timestamp":1630713600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Legionella pneumophila is ubiquitous in aquatic environments and responsible for severe pneumonia in humans through inhalation of aerosol containing Legionella spp. Macrolides and fluoroquinolones are frequently used antimicrobials, but treatment failures are increasingly being reported. As susceptibility testing is not routinely performed, this study aimed to determine the minimum inhibitory concentrations (MICs) on 58 environmental Legionella pneumophila strains (24 of serogroup 1 and 34 of non-serogroup 1) isolated in Northern Italy. MICs of azithromycin, erythromycin, ciprofloxacin, levofloxacin, and rifampicin were determined by the microdilution method using buffered yeast extract broth supplemented with \u03b1-ketoglutarate (BYE\u03b1). Seventy-five percent of Legionella pneumophila isolates showed MIC values below the tentative highest MICs indicated by the European Committee on Antimicrobial Susceptibility Testing (EUCAST); rifampicin was the most active agent with MIC90 values below 0.008 mg\/L. Interestingly, one isolate was tested and found to be PCR-positive for the azithromycin LpeAB active efflux system, further confirmed by the reserpine\/resazurin microtiter assay. In conclusion, this study has provided additional susceptibility data for environmental Legionella pneumophila isolates from Northern Italy demonstrating, in general, low MICs values for the tested antimicrobials, although one strain tested was shown to possess the LpeAB resistance determinant, indicating that future surveillance studies are warranted.<\/jats:p>","DOI":"10.3390\/ijerph18179352","type":"journal-article","created":{"date-parts":[[2021,9,6]],"date-time":"2021-09-06T13:15:56Z","timestamp":1630934156000},"page":"9352","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["Antibiotic Susceptibility of Environmental Legionella pneumophila Strains Isolated in Northern Italy"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6166-1134","authenticated-orcid":false,"given":"Clementina Elvezia","family":"Cocuzza","sequence":"first","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy"},{"name":"MicroMiB Biorepository, University of Milano-Bicocca, Associated Member of the JRU MIRRI-IT, Via Cadore, 20900 Monza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2273-6986","authenticated-orcid":false,"given":"Marianna","family":"Martinelli","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy"},{"name":"MicroMiB Biorepository, University of Milano-Bicocca, Associated Member of the JRU MIRRI-IT, Via Cadore, 20900 Monza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Federica","family":"Perdoni","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy"},{"name":"MicroMiB Biorepository, University of Milano-Bicocca, Associated Member of the JRU MIRRI-IT, Via Cadore, 20900 Monza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6112-7572","authenticated-orcid":false,"given":"Chiara","family":"Giubbi","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1481-5724","authenticated-orcid":false,"given":"Maria Erica Alessandra","family":"Vinetti","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Enrico","family":"Calaresu","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sergio","family":"Frugoni","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Scaturro","sequence":"additional","affiliation":[{"name":"National Reference Laboratory for Legionella, Department of Infectious Diseases, Istituto Superiore di Sanit\u00e0, 00161 Roma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria Luisa","family":"Ricci","sequence":"additional","affiliation":[{"name":"National Reference Laboratory for Legionella, Department of Infectious Diseases, Istituto Superiore di Sanit\u00e0, 00161 Roma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0143-3601","authenticated-orcid":false,"given":"Rosario","family":"Musumeci","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy"},{"name":"MicroMiB Biorepository, University of Milano-Bicocca, Associated Member of the JRU MIRRI-IT, Via Cadore, 20900 Monza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1128\/CMR.00029-14","article-title":"Current and emerging Legionella diagnostics for laboratory and outbreak investigations","volume":"28","author":"Mercante","year":"2015","journal-title":"Clin. 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