Abstract:

Objective: To analyze the clinical features and virulence gene characteristics of Klebsiella pneumoniae multi-site infections in patients with hospital-acquired pneumonia, as well as the risk factors for death within 30 days in patients with multi-site infections, in order to provide help for clinical anti-infective treatment. Methods: The case data of hospital-acquired pneumonia patients with Klebsiella pneumoniae isolated in sputum culture from March 2018 to June 2023 in Peking University Third Hospital were selected for retrospective analysis, and a total of 128 consecutive patients were enrolled, of whom 35 were in the multi-site infection group and 93 were in the lung infection group, and the clinical data, strain sequence typing, and virulence-related genes of the patients in the two groups were analyzed and compared. Results: The differences in age, gender, proportion of the patients with length of hospital stay ≥30 days, antibiotic exposure rate within 90 days and 30-day mortality rate between the two groups were statistically significant (all P < 0.05); the differences in the proportions of combined interstitial lung disease, myocardial infarction, peripheral vascular disease, peptic ulcer, diabetes mellitus and hemiplegia between the two groups were statistically significant (all P < 0.05). The proportions of patients with Glasgow coma scale (GCS) scores < 8 points, the proportion of the patients who underwent peripherally inserted central catheter (PICC) and gastric tube invasive operation, the proportion of the presence of pleural effusion and infectious shock in the multi-site infection group were significantly higher than those of the pulmonary infection group (all P < 0.05). The blood procalcitonin (PCT) level in the multi-site infection group was significantly higher than that of the pulmonary infection group (P=0.004), and the red blood cell count and hemoglobin level were significantly lower than those of the pulmonary infection group (P < 0.001). The proportion of ST11 and the detection rates of virulence genes iroB, ybtA, irp1 and fyuA in Klebsiella pneumoniae strains in the multi-site infection group were significantly higher than those in the pulmonary infection group (P < 0.05). According to the occurrence of death within 30 days, the patients in the multi-site infection group were further divided into the multi-site infection survival group (n=21) and the non-survival group (n=14). Multivariate analysis showed that septic shock was an independent risk factor for death within 30 days of multi-site infection (P=0.045, OR=38.510). Conclusion: Patients with Klebsiella pneumoniae multi-site infection were mainly found in patients with advanced age, female, more comorbidities, performing invasive operation and having history of antimicrobial drug exposure within 90 days. They had lower erythrocyte counts, hemoglobin levels and higher PCT levels, and were prone to pleural effusion, infectious shock. Infectious shock was an independent risk factor for death within 30 days in patients with Klebsiella pneumoniae multi-site infection. ST11 type was the most prevalent type of multi-site infectious strains, and the virulence genes iroB, ybtA, irp1, fyuA were more prevalent.

Key words: Hospital-acquired pneumonia, Klebsiella pneumoniae, Virulence, Bacterial genes, Multi-site infection