Microbial etiology of pleural infections – A Retrospective view in a Portuguese Hospital

Pleural infections, notably empyema and parapneumonic effusions, require an accurate microbiological diagnosis for effective treatment, influenced by the distinction between community-acquired and hospital-acquired infections. A retrospective review (2020-2023) of pleural fluid samples from 51 patients hospitalized in a Pulmonology unit was conducted to assess the microbial etiology and compare pathogen prevalence between community-acquired and hospital-acquired infections. 51 patients, 72.5% male, average age of 65 years, 40% non-smokers. Most infections(92.2%) were community-acquired; 54.9% had empyema, others had parapneumonic effusions. Pleural fluid cultures yielded 36%, and biopsies 50%. Community infections were predominantly caused by Gram-positive <italic>Streptococcus pneumoniae</italic>(N=7) and Gram-negative <italic>Haemophilus influenzae</italic>(N=5), with <italic>Mycobacterium tuberculosis</italic> also significant(N=4). Hospital-acquired infections, less frequent, featured resistant Gram-negative bacteria like <italic>Pseudomonas aeruginosa</italic>. <italic>Strepococcus viridans</italic> was in both settings. Overall mortality was 10%. Community-acquired infections were mainly due to Gram-positive cocci (dominance of <italic>Strp. pneumoniae</italic>) emphasizing vaccination and early intervention importance. Hospital-acquired infections involved resistant Gram-negative pathogens, highlighting the need for tailored empirical treatments. The low hospital mortality rate underscores current treatment protocols. <fig><object-id>erj;64/suppl_68/PA1496/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>