OBJECTIVE To explore the distribution of pathogenic bacteria and factors influencing infection severity in patients with severe traumatic brain injury (TBI) complicated by pulmonary infection.

METHODS A retrospective analysis was conducted on the clinical data of 168 patients with severe TBI complicated by pulmonary infection admitted to the department of neurosurgery, Liaocheng Second People′s Hospital from Nov. 2019 to Nov. 2024. Based on their Clinical Pulmonary Infection Score (CPIS), patients were categorized into a low-risk group (CPIS ≤ 6, n=92) and a high-risk group (CPIS > 6, n=76). Clinical data and differences in the distribution of pathogenic bacteria were compared between the two groups.

RESULTS A total of 187 pathogenic bacteria were isolated from 168 sputum specimens, including 149 strains of gram-negative bacteria (79.68%), 31 strains of gram-positive bacteria (16.58%) and 7 strains of fungi (3.74%). The proportion of patients with Glasgow Coma Scale (GCS) scores ≤ 5 and tracheotomy duration > 7 days in the high-risk group was higher than that in the low-risk group (P < 0.05). Multivariate logistic regression analysis revealed that GCS scores and tracheotomy duration were independent influencing factors for the severity of pulmonary infection in patients with severe TBI (P < 0.05).

CONCLUSION Gram-negative bacteria are the predominant pathogenic bacterium in patients with severe TBI complicated by pulmonary infection, with GCS scores and tracheotomy duration being the main influencing factors for the severity of pulmonary infection.