Evaluation of factors affecting Pneumonia Severity Index and antibiotic resistance status in culture-proven bacterial pneumonia
Year: 2026
Type: article
Study design: Observational Study
Abstract: Introduction 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–inflammatory biomarkers. This study aimed to evaluate the impact of comorbidities, etiological agents, antimicrobial resistance, and immune–inflammatory markers on PSI scores in patients with culture-proven bacterial pneumonia. Materials and methods 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–inflammation index (SII), C-reactive protein, and albumin levels were evaluated in relation to PSI scores. Results Most patients were aged ≥65 years and had at least one comorbidity. Gram-negative bacteria predominated, with Pseudomonas aeruginosa being the most frequently isolated pathogen. Multidrug resistance was most commonly observed in Acinetobacter baumannii , Klebsiella spp., and Escherichia coli . 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 ( p < 0.05). Patients with MDR isolated had significantly higher mean PSI scores than those without MDR. Conclusion In culture-proven bacterial pneumonia, comorbidity burden, antimicrobial resistance–particularly multidrug resistance–and elevated immune–inflammatory 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.
Source: Frontiers in Medicine
Authors: İlknur Kaya, Aynur Gülcan, İnci Arıkan
Institution: Kutahya Saglik Bilimleri Universitesi
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7127457641