{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,6]],"date-time":"2026-02-06T21:17:54Z","timestamp":1770412674505,"version":"3.49.0"},"reference-count":23,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,6]],"date-time":"2026-02-06T00:00:00Z","timestamp":1770336000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Background: AMR is a public health concern which leads to high global morbidity and mortality. Immunocompromised patients, who are more susceptible to contracting potentially life-threatening infections, are faced with reduced treatment options due to emerging AMR. Ceftolozane\/tazobactam is a novel \u03b2-lactam\/\u03b2-lactamase inhibitor which displays effectiveness against resistant Gram-negative infections. Methods: SPECTRA was a multinational, observational study conducted in seven countries including 617 patients who received \u226548 h of ceftolozane\/tazobactam. Medical-record data were collected up to 6 months before treatment and 30 days after the final dose or until death. This analysis describes clinical outcomes and healthcare resource use in patients with sepsis or who were immunocompromised, specifically in patients with hematologic malignancy with and without solid tumor, febrile neutropenia, and solid organ transplant patients. Results: Clinical success ranged from 50.0% in patients with hematologic malignancy and solid tumor to 69.4% in 38 patients with febrile neutropenia. All-cause in-hospital mortality was 23.1\u201342.9%, with the lowest rates in patients with solid organ transplant. ICU admission was 46.4\u201368.2% across subpopulations (excluding febrile neutropenia) with the lowest rates in patients with hematologic malignancy. ICU length of stay was lowest within transplant patients (9 days) and highest within the hematologic malignancy and solid tumor population (32 days). Conclusions: The results from this sub analysis of SPECTRA showed that ceftolozane\/tazobactam was associated with clinical success in the selected immunocompromised and sepsis patient populations and may lead to reduced morbidity, mortality, and healthcare-resource use. Further research is required to standardize treatment protocols and improve patient outcomes.<\/jats:p>","DOI":"10.3390\/antibiotics15020179","type":"journal-article","created":{"date-parts":[[2026,2,6]],"date-time":"2026-02-06T10:05:47Z","timestamp":1770372347000},"page":"179","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Clinical Outcomes and Healthcare Resource Utilization of Ceftolozane\/Tazobactam in Vulnerable Patient Populations"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6036-9526","authenticated-orcid":false,"given":"Emre","family":"Y\u00fccel","sequence":"first","affiliation":[{"name":"Merck & Co., Inc., P.O. Box 1000, Rahway, NJ 07065, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9374-0811","authenticated-orcid":false,"given":"Alex","family":"Soriano","sequence":"additional","affiliation":[{"name":"Hospital Clinic, 08036 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6523-8229","authenticated-orcid":false,"given":"Florian","family":"Thalhammer","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medizinische Universit\u00e4t Wien, 1090 Wien, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stefan","family":"Kluge","sequence":"additional","affiliation":[{"name":"Department of Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mike","family":"Allen","sequence":"additional","affiliation":[{"name":"MSD (UK) Limited, London, 120 Moorgate, London EC2M 6UR, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jessica","family":"Levy","sequence":"additional","affiliation":[{"name":"Merck & Co., Inc., P.O. Box 1000, Rahway, NJ 07065, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huina","family":"Yang","sequence":"additional","affiliation":[{"name":"Tan Tock Seng Hospital, 11 Jln Tan Tock Seng, Singapore 308433, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sunny","family":"Kaul","sequence":"additional","affiliation":[{"name":"Royal Brompton & Harefield NHS Foundation Trust, Britten St, London SW3 6PY, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,6]]},"reference":[{"key":"ref_1","unstructured":"WHO (2026, January 26). Antimicrobial Resistance. 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