{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T17:20:12Z","timestamp":1790011212306,"version":"4.0.1"},"reference-count":40,"publisher":"Oxford University Press (OUP)","license":[{"start":{"date-parts":[[2020,5,25]],"date-time":"2020-05-25T00:00:00Z","timestamp":1590364800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"name":"MSD-Merck Sharp & Dohme","award":["57161"],"award-info":[{"award-number":["57161"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Objectives<\/jats:title><jats:p>We evaluated the in vitro activity of ceftolozane\/tazobactam and comparator agents against MDR non-MBL Pseudomonas aeruginosa isolates collected from nine Greek hospitals and we assessed the potential synergistic interaction between ceftolozane\/tazobactam and amikacin.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>A total of 160 non-MBL P. aeruginosa isolates collected in 2016 were tested for susceptibility to ceftolozane\/tazobactam and seven comparator agents including ceftazidime\/avibactam. Time\u2013kill assays were performed for synergy testing using ceftolozane\/tazobactam 60 or 7.5\u2009mg\/L, corresponding to the peak and trough concentrations of a 1.5\u2009g q8h dose, respectively, in combination with 69\u2009mg\/L amikacin, corresponding to the free peak plasma concentration. Synergy was defined as a \u22652\u2009log10\u2009cfu\/mL reduction compared with the most active agent.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Overall, ceftolozane\/tazobactam inhibited 64.4% of the P. aeruginosa strains at \u22644\u2009mg\/L. Colistin was the most active agent (MIC50\/90, 0.5\/2\u2009mg\/L; 96.3% susceptible) followed by ceftazidime\/avibactam (MIC50\/90, 4\/16\u2009mg\/L; 80.6% susceptible). GES-type enzymes were predominantly responsible for ceftolozane\/tazobactam resistance; 81.6% of the non-producers were susceptible. MICs for the P. aeruginosa isolates selected for synergy testing were 2\u201332\u2009mg\/L ceftolozane\/tazobactam and 2\u2013128\u2009mg\/L amikacin. The combination of ceftolozane\/tazobactam with amikacin was synergistic against 85.0% of all the isolates tested and against 75.0% of the GES producers. No antagonistic interactions were observed.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Ceftolozane\/tazobactam demonstrated good in vitro activity against MDR\/XDR P. aeruginosa clinical isolates, including strains with co-resistance to other antipseudomonal drugs. In combination with amikacin, a synergistic interaction at 24\u2009h was observed against 85.0% of P. aeruginosa strains tested, including isolates with ceftolozane\/tazobactam MICs of 32\u2009mg\/L or GES producers.<\/jats:p><\/jats:sec>","DOI":"10.1093\/jac\/dkaa160","type":"journal-article","created":{"date-parts":[[2020,4,2]],"date-time":"2020-04-02T19:10:35Z","timestamp":1585854635000},"source":"Crossref","is-referenced-by-count":11,"title":["In vitro activity of ceftolozane\/tazobactam alone and in combination with amikacin against MDR\/XDR Pseudomonas aeruginosa isolates from Greece"],"prefix":"10.1093","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6455-9848","authenticated-orcid":false,"given":"Irene","family":"Galani","sequence":"first","affiliation":[{"name":"Infectious Diseases Laboratory, 4th Department of Internal Medicine, National and Kapodistrian University of Athens, Athens, Greece"},{"name":"University General Hospital \u2018ATTIKON\u2019, Chaidari, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vassiliki","family":"Papoutsaki","sequence":"first","affiliation":[{"name":"Infectious Diseases Laboratory, Hygeia General Hospital, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irene","family":"Karantani","sequence":"first","affiliation":[{"name":"Infectious Diseases Laboratory, Hygeia General Hospital, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2226-0239","authenticated-orcid":false,"given":"Ilias","family":"Karaiskos","sequence":"first","affiliation":[{"name":"1st Internal Medicine & Infectious Diseases Clinic, Hygeia General Hospital, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lamprini","family":"Galani","sequence":"first","affiliation":[{"name":"1st Internal Medicine & Infectious Diseases Clinic, Hygeia General Hospital, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Panagiota","family":"Adamou","sequence":"first","affiliation":[{"name":"Infectious Diseases Laboratory, 4th Department of Internal Medicine, National and Kapodistrian University of Athens, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ioannis","family":"Deliolanis","sequence":"first","affiliation":[{"name":"Department of Microbiology, \u2018Laikon\u2019 General Hospital, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antigoni","family":"Kodonaki","sequence":"first","affiliation":[{"name":"Department of Microbiology, \u2018Laikon\u2019 General Hospital, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eleni","family":"Papadogeorgaki","sequence":"first","affiliation":[{"name":"Microbiology Laboratory, Hygeia General Hospital, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Margarita","family":"Markopoulou","sequence":"first","affiliation":[{"name":"Microbiology Laboratory, Hygeia General Hospital, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sofia","family":"Maraki","sequence":"first","affiliation":[{"name":"Department of Clinical Bacteriology, Parasitology, Zoonoses and Geographical Medicine, University Hospital of Heraklion, Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Damala","sequence":"first","affiliation":[{"name":"Microbiology Department, \u2018Alexandra\u2019 General Hospital of Athens, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eleni","family":"Prifti","sequence":"first","affiliation":[{"name":"Microbiology Department, \u2018Alexandra\u2019 General Hospital of Athens, Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eleni","family":"Vagiakou","sequence":"first","affiliation":[{"name":"Microbiology Laboratory, General Hospital of Athens \u2018G. 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