{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,2]],"date-time":"2026-11-02T07:59:52Z","timestamp":1793606392842,"version":"4.5.0"},"reference-count":38,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2024,4,25]],"date-time":"2024-04-25T00:00:00Z","timestamp":1714003200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Belgian Ministry of Social Affairs"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Legionella pneumophila can cause a large panel of symptoms besides the classic pneumonia presentation. Here we present a case of fatal nosocomial cellulitis in an immunocompromised patient followed, a year later, by a second case of Legionnaires\u2019 disease in the same ward. While the first case was easily assumed as nosocomial based on the date of symptom onset, the second case required clear typing results to be assigned either as nosocomial and related to the same environmental source as the first case, or community acquired. To untangle this specific question, we applied core-genome multilocus typing (MLST), whole-genome single nucleotide polymorphism and whole-genome MLST methods to a collection of 36 Belgian and 41 international sequence-type 1 (ST1) isolates using both thresholds recommended in the literature and tailored threshold based on local epidemiological data. Based on the thresholds applied to cluster isolates together, the three methods gave different results and no firm conclusion about the nosocomial setting of the second case could been drawn. Our data highlight that despite promising results in the study of outbreaks and for large-scale epidemiological investigations, next-generation sequencing typing methods applied to ST1 outbreak investigation still need standardization regarding both wet-lab protocols and bioinformatics. A deeper evaluation of the L. pneumophila evolutionary clock is also required to increase our understanding of genomic differences between isolates sampled during a clinical infection and in the environment.<\/jats:p>","DOI":"10.3390\/microorganisms12050857","type":"journal-article","created":{"date-parts":[[2024,4,26]],"date-time":"2024-04-26T10:56:32Z","timestamp":1714128992000},"page":"857","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["From Investigating a Case of Cellulitis to Exploring Nosocomial Infection Control of ST1 Legionella pneumophila Using Genomic Approaches"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0250-2664","authenticated-orcid":false,"given":"Charlotte","family":"Michel","sequence":"first","affiliation":[{"name":"Department of Microbiology, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium"},{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles (LHUB-ULB), Rue Haute 322, 1000 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8075-1012","authenticated-orcid":false,"given":"Fedoua","family":"Echahidi","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5233-0667","authenticated-orcid":false,"given":"Sammy","family":"Place","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Infectious Diseases, EpiCURA Hospital, 7301 Hornu, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lorenzo","family":"Filippin","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Infectious Diseases, EpiCURA Hospital, 7301 Hornu, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-1491-5021","authenticated-orcid":false,"given":"Vincent","family":"Colombie","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Infectious Diseases, EpiCURA Hospital, 7301 Hornu, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1706-6869","authenticated-orcid":false,"given":"Nicolas","family":"Yin","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles (LHUB-ULB), Rue Haute 322, 1000 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Delphine","family":"Martiny","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles (LHUB-ULB), Rue Haute 322, 1000 Brussels, Belgium"},{"name":"Faculty of Medicine and Pharmacy, Mons University, Chemin du Champ de Mars 37, 7000 Mons, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olivier","family":"Vandenberg","sequence":"additional","affiliation":[{"name":"Innovation and Business Development Unit, Laboratoire Hospitalier Universitaire de Bruxelles (LHUB-ULB), Rue Haute 322, 1000 Brussels, Belgium"},{"name":"Centre for Environmental Health and Occupational Health, School of Public Health, Universit\u00e9 Libre de Bruxelles (ULB), Avenue Roosevelt 50, 1050 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7756-3691","authenticated-orcid":false,"given":"Denis","family":"Pi\u00e9rard","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4544-0635","authenticated-orcid":false,"given":"Marie","family":"Hallin","sequence":"additional","affiliation":[{"name":"Centre for Environmental Health and Occupational Health, School of Public Health, Universit\u00e9 Libre de Bruxelles (ULB), Avenue Roosevelt 50, 1050 Brussels, Belgium"},{"name":"European Plotkin Institute for Vaccinology (EPIV), Universit\u00e9 Libre de Bruxelles (ULB), Avenue Roosevelt 50, 1050 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,4,25]]},"reference":[{"key":"ref_1","first-page":"1800192","article-title":"Air-conditioner cooling towers as complex reservoirs and continuous source of Legionella pneumophila infection evidenced by a genomic analysis study in 2017, 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