{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T17:35:18Z","timestamp":1770140118822,"version":"3.49.0"},"reference-count":27,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T00:00:00Z","timestamp":1770076800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>The Pneumonia Severity Index (PSI) is a widely used to assess disease severity and guide hospitalization decisions in patients with pneumonia. However, PSI does not incorporate microbiological characteristics, antimicrobial resistance patterns, or immune\u2013inflammatory biomarkers. This study aimed to evaluate the impact of comorbidities, etiological agents, antimicrobial resistance, and immune\u2013inflammatory markers on PSI scores in patients with culture-proven bacterial pneumonia.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and methods<\/jats:title>\n                    <jats:p>This retrospective study included patients with culture-proven bacterial pneumonia treated at a tertiary care center between January 2019 and April 2023. Demographic characteristics, comorbidities, intensive care unit (ICU) admission, etiological agents, antimicrobial resistance patterns, and multidrug resistance (MDR) status were analyzed. Laboratory parameters, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune\u2013inflammation index (SII), C-reactive protein, and albumin levels were evaluated in relation to PSI scores.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Most patients were aged \u226565 years and had at least one comorbidity. Gram-negative bacteria predominated, with\n                      <jats:italic>Pseudomonas aeruginosa<\/jats:italic>\n                      being the most frequently isolated pathogen. Multidrug resistance was most commonly observed in\n                      <jats:italic>Acinetobacter baumannii<\/jats:italic>\n                      ,\n                      <jats:italic>Klebsiella<\/jats:italic>\n                      spp., and\n                      <jats:italic>Escherichia coli<\/jats:italic>\n                      . Higher PSI scores were significantly associated with a greater comorbidity burden, presence of MDR pathogens, elevated NLR, PLR, MLR, and SII values, and lower albumin levels (\n                      <jats:italic>p<\/jats:italic>\n                      &amp;lt; 0.05). Patients with MDR isolated had significantly higher mean PSI scores than those without MDR.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>In culture-proven bacterial pneumonia, comorbidity burden, antimicrobial resistance\u2013particularly multidrug resistance\u2013and elevated immune\u2013inflammatory biomarkers are associated with higher PSI scores. These findings highlight the importance of considering community-onset healthcare-associated pneumonia and integrating local antimicrobial resistance surveillance and laboratory biomarkers into clinical risk stratification. Further multicenter prospective studies are warranted to validate these associations.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fmed.2026.1720340","type":"journal-article","created":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T06:29:56Z","timestamp":1770100196000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Evaluation of factors affecting Pneumonia Severity Index and antibiotic resistance status in culture-proven bacterial pneumonia"],"prefix":"10.3389","volume":"13","author":[{"given":"\u0130lknur","family":"Kaya","sequence":"first","affiliation":[{"name":"Department of Chest Diseases, Faculty of Medicine, K\u00fctahya Health Sciences University","place":["K\u00fctahya, T\u00fcrkiye"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Aynur","family":"G\u00fclcan","sequence":"additional","affiliation":[{"name":"Department of Medical Microbiology, Faculty of Medicine, K\u00fctahya Health Sciences University","place":["K\u00fctahya, T\u00fcrkiye"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"\u0130nci","family":"Ar\u0131kan","sequence":"additional","affiliation":[{"name":"Department of Public Health, Faculty of Medicine, K\u00fctahya Health Sciences University","place":["K\u00fctahya, T\u00fcrkiye"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,2,3]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"1619","DOI":"10.1056\/NEJMra1312885","article-title":"Community-acquired pneumonia.","volume":"371","author":"Musher","year":"2014","journal-title":"N Engl J Med."},{"key":"B2","doi-asserted-by":"publisher","first-page":"153","DOI":"10.1513\/AnnalsATS.201407-305OC","article-title":"Risk factors associated with potentially antibiotic-resistant pathogens in community-acquired pneumonia.","volume":"12","author":"Prina","year":"2015","journal-title":"Ann Am Thorac Soc."},{"key":"B3","doi-asserted-by":"publisher","first-page":"419","DOI":"10.1016\/S0873-2159(15)30360-3","article-title":"Documento de consenso sobre Pneumonia Nosocomial. Sociedade Portuguesa de Pneumologia e Sociedade Portuguesa de Cuidados Intensivos [Consensus document on Nosocomial Pneumonia. Brazilian Society of Pulmonology and Brazilian Society of Intensive Care].","volume":"13","author":"Froes","year":"2007","journal-title":"Rev Port Pneumol."},{"key":"B4","doi-asserted-by":"crossref","DOI":"10.1002\/9780470518274","volume-title":"Nosocomial Pneumonia: Strategies for Management.","author":"Rello","year":"2007"},{"key":"B5","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1164\/rccm.201002-0272CI","article-title":"Management of community-acquired pneumonia in adults.","volume":"183","author":"Waterer","year":"2011","journal-title":"Am J Respir Crit Care Med."},{"key":"B6","first-page":"191","article-title":"[Community-acquired pneumonia based on the Turkish national data].","volume":"55","author":"Ozl\u00fc","year":"2007","journal-title":"Tuberk Toraks."},{"key":"B7","doi-asserted-by":"publisher","first-page":"415","DOI":"10.1056\/NEJMoa1500245","article-title":"Community-acquired pneumonia requiring hospitalization among U.S. adults.","volume":"373","author":"Jain","year":"2015","journal-title":"N Engl J Med."},{"key":"B8","doi-asserted-by":"publisher","first-page":"665","DOI":"10.1016\/j.emc.2018.07.001","article-title":"Community-acquired pneumonia.","volume":"36","author":"Rider","year":"2018","journal-title":"Emerg Med Clin North Am."},{"key":"B9","doi-asserted-by":"publisher","first-page":"519","DOI":"10.2165\/11591980-000000000-00000","article-title":"Elderly patients with community-acquired pneumonia: optimal treatment strategies.","volume":"28","author":"Thiem","year":"2011","journal-title":"Drugs Aging."},{"key":"B10","first-page":"37","article-title":"[Community acquired pneumonia in patients requiring hospitalization].","volume":"81","author":"Alonso","year":"2021","journal-title":"Medicina."},{"key":"B11","doi-asserted-by":"publisher","first-page":"e20200257","DOI":"10.36416\/1806-3756\/e20200257","article-title":"Charlson comorbidity index and other predictors of in-hospital mortality among adults with community-acquired pneumonia.","volume":"47","author":"Bahlis","year":"2021","journal-title":"J Bras Pneumol."},{"key":"B12","doi-asserted-by":"publisher","first-page":"173","DOI":"10.17219\/dmp\/166666","article-title":"Charlson comorbidity index and the severity of community-acquired pneumonia caused by SARS-CoV-2: a retrospective analysis.","volume":"61","author":"Marushchak","year":"2024","journal-title":"Dent Med Probl."},{"key":"B13","doi-asserted-by":"publisher","first-page":"e0001522","DOI":"10.1128\/cmr.00015-22","article-title":"The microbial etiology of community-acquired pneumonia in adults: from classical bacteriology to host transcriptional signatures.","volume":"35","author":"Gadsby","year":"2022","journal-title":"Clin Microbiol Rev."},{"key":"B14","doi-asserted-by":"publisher","first-page":"107663","DOI":"10.1016\/j.pharmthera.2020.107663","article-title":"Updates on community acquired pneumonia management in the ICU.","volume":"217","author":"Nair","year":"2021","journal-title":"Pharmacol Ther."},{"key":"B15","doi-asserted-by":"publisher","first-page":"3800","DOI":"10.3390\/jcm9123800","article-title":"Impact of Pseudomonas aeruginosa infection on patients with chronic inflammatory airway diseases.","volume":"9","author":"Garcia-Clemente","year":"2020","journal-title":"J Clin Med."},{"key":"B16","doi-asserted-by":"publisher","first-page":"25","DOI":"10.1038\/s41572-021-00259-0","article-title":"Pneumonia.","volume":"7","author":"Torres","year":"2021","journal-title":"Nat Rev Dis Primers."},{"key":"B17","doi-asserted-by":"publisher","first-page":"415","DOI":"10.1016\/j.chest.2016.03.042","article-title":"Community-acquired pneumonia due to multidrug- and non-multidrug-resistant Pseudomonas aeruginosa.","volume":"150","author":"Cill\u00f3niz","year":"2016","journal-title":"Chest."},{"key":"B18","doi-asserted-by":"publisher","first-page":"660","DOI":"10.1111\/resp.12506","article-title":"Risk factors and antibiotic therapy in P. aeruginosa community-acquired pneumonia.","volume":"20","author":"Sibila","year":"2015","journal-title":"Respirology."},{"key":"B19","doi-asserted-by":"publisher","first-page":"1701190","DOI":"10.1183\/13993003.01190-2017","article-title":"Burden and risk factors for Pseudomonas aeruginosa community-acquired pneumonia: a multinational point prevalence study of hospitalised patients.","volume":"52","author":"Restrepo","year":"2018","journal-title":"Eur Respir J."},{"key":"B20","doi-asserted-by":"publisher","first-page":"1604","DOI":"10.1093\/cid\/ciz1049","article-title":"Blood cultures versus respiratory cultures: 2 different views of pneumonia.","volume":"71","author":"Haessler","year":"2020","journal-title":"Clin Infect Dis."},{"key":"B21","doi-asserted-by":"publisher","first-page":"e45","DOI":"10.1164\/rccm.201908-1581ST","article-title":"Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American thoracic society and infectious diseases society of America.","volume":"200","author":"Metlay","year":"2019","journal-title":"Am J Respir Crit Care Med."},{"key":"B22","volume-title":"WHO Report on Surveillance of Antibiotic Consumption.","year":"2019"},{"key":"B23","doi-asserted-by":"publisher","first-page":"73","DOI":"10.1186\/s42269-024-01228-9","article-title":"Prevalence and patterns of multidrug-resistant bacteria isolated from sputum samples of patients with bacterial pneumonia at a tertiary hospital in Tanzania.","volume":"48","author":"Kamori","year":"2024","journal-title":"Bull Natl Res Centre."},{"key":"B24","doi-asserted-by":"publisher","first-page":"1796","DOI":"10.1111\/jgs.14894","article-title":"Neutrophil-to-lymphocyte ratio: an emerging marker predicting prognosis in elderly adults with community-acquired Pneumonia.","volume":"65","author":"Cataudella","year":"2017","journal-title":"J Am Geriatr Soc."},{"key":"B25","doi-asserted-by":"publisher","first-page":"e630","DOI":"10.1002\/hsr2.630","article-title":"Neutrophil-lymphocyte ratio as a predictor of adverse outcome in patients with community-acquired pneumonia: a systematic review.","volume":"5","author":"Kuikel","year":"2022","journal-title":"Health Sci Rep."},{"key":"B26","doi-asserted-by":"publisher","first-page":"186","DOI":"10.5603\/mrj.96312","article-title":"Use of the systemic immune-inflammation index to predict the severity of pneumonia in the emergency department.","volume":"8","author":"Tortum","year":"2023","journal-title":"Med Res J."},{"key":"B27","doi-asserted-by":"publisher","first-page":"8","DOI":"10.4103\/tjem.tjem_198_23","article-title":"Unraveling the clinical significance and prognostic value of the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, systemic immune-inflammation index, systemic inflammation response index, and delta neutrophil index: an extensive literature review.","volume":"24","author":"Islam","year":"2024","journal-title":"Turk J Emerg Med."}],"container-title":["Frontiers in Medicine"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmed.2026.1720340\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T06:29:57Z","timestamp":1770100197000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmed.2026.1720340\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,3]]},"references-count":27,"alternative-id":["10.3389\/fmed.2026.1720340"],"URL":"https:\/\/doi.org\/10.3389\/fmed.2026.1720340","relation":{},"ISSN":["2296-858X"],"issn-type":[{"value":"2296-858X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,3]]},"article-number":"1720340"}}