Abstract

Reports about the increase in aggressive infections caused by highly virulent Klebsiella pneumoniae have risen in recent times. Nevertheless, the impact of its virulence on the progress and consequences of pneumonia patients has yet to be studied. Our research intended to evaluate and relate the clinical characteristics of highly virulent Klebsiella pneumoniae and classical Klebsiella pneumoniae strains obtained from intensive care unit patients who had pneumonia induced by Klebsiella pneumoniae. In this retrospective analysis, we included 173 individuals diagnosed with pneumonia induced by Klebsiella pneumoniae. We collected relevant demographic and clinical information from medical records. The study involved an examination of genetic markers associated with K1 and K2, antimicrobial sensitivity, and the presence of virulence genes, including regulator of mucoid phenotype A, isoform usage two-step analysis, enteroBactin, yersiniabactin, Klebsiella ferric iron uptake, fimbrial adhesin gene, and allantoin metabolism. Strains that showed both regulator of mucoid phenotype A and isoform usage two-step analysis were classified as hyper virulent Klebsiella pneumoniae (n=66), while the rest were designated as classic Klebsiella pneumoniae (n=107). The prevalence of patients with highly virulent Klebsiella pneumoniae strains was noticeably higher for bacteraemia (24.2 % vs. 8.4 %, p=0.004), metastatic spread (25.8 % vs. 8.4 %, p=0.002), liver abscess (24.2 % vs. 3.7 %, p<0.001), serum creatinine (63.6 % vs. 42.1 %, p=0.006), and 30 d mortality (25.8 % vs. 8.4 %, p=0.002). All 173 Klebsiella pneumoniae strains showed consistent sensitivity to the drug ampicillin. Multivariate regression analysis demonstrated that metastatic spread (odd ratio=3.596, 95 % confidence interval=1.193-10.838; p=0.023), liver abscess (odd ratio=7.537, 95 % confidence interval=1.850-30.715; p=0.005), acute physiology and chronic health evaluation II score (odd ratio=1.616, 95 % confidence interval=1.365-1.914; p<0.001), and serum creatinine (odd ratio=2.506, 95 % confidence interval=1.125-5.587; p=0.025) were all associated with highly virulent Klebsiella pneumoniae infection in patients with pneumonia induced by Klebsiella pneumoniae. Several clinical risk factors linked to highly virulent Klebsiella pneumoniae infection were identified in pneumonia patients with Klebsiella pneumoniae.