Cytokine Profiling and Bacterial Spectrum in Patients with Hospital-Acquired Pneumonia

Background: This study was designed to identify bacterial causes of hospital-acquired pneumonia )HAP), determine serum levels of IL-6, IL-22, and TGF-β in HAP patients, and compare the levels of these cytokines with those in healthy individuals. Additionally, the study investigated the relationship between cytokine profiles and bacterial species responsible for HAP in Diyala Governorate, Iraq.
Materials & Methods: Samples (blood and sputum) were collected from 150 patients admitted to Baquba Teaching Hospital in Iraq between December 2023 and May 2024. All patients showed clinical signs and symptoms of pneumonia. Sputum samples were cultured on differential media, and 58 samples displayed bacterial growth. Bacterial species were identified using the Vitek system. In addition, 32 blood samples were obtained from healthy individuals as controls. Serum levels of IL-6, IL-22, and TGF-β were measured in both groups using enzyme-linked immunosorbent assay (ELISA).
Findings: The results revealed that IL-6, IL-22, and TGF-β levels were significantly higher in patients (19.02±1.675 pg/mL, 446.1±3.074 pg/mL, and 14.69±0.191 ng/mL, respectively) compared to healthy controls (7.206±0.274 ng/mL, 365.6±4.265 pg/mL, and 5.88±0.17 ng/mL, respectively). The prevalence of HAP was higher in males. IL-6 and IL-22 levels were significantly higher in males, whereas TGF-β levels were lower compared to females.
Conclusion: Significant differences were observed in IL-6, IL-22, and TGF-β levels between patients and healthy individuals. Understanding the cytokine network involved in HAP pathogenesis may contribute to developing targeted therapies and improving clinical outcomes.