Comparison of the clinical characteristics and outcomes of bloodstream infections caused by Raoultella species and Klebsiella pneumoniae

Abstract

Background: There have been few clinical studies of Raoultella infections but Raoultella is potentially virulent and multidrug resistant. The aims of the study were to compare the clinical characteristics and outcomes of patients with Raoultella and Klebsiella pneumoniae bloodstream infections (BSIs). Methods: We retrospectively reviewed the records of patients with Raoultella and K. pneumoniae BSIs admitted to a tertiary hospital between 2008 and 2017. Results: A total of 37 cases of Raoultella BSIs were identified and matched to 160 cases of K. pneumoniae BSIs by age and sex using propensity score matching. Patients with Raoultella BSIs were more likely to have underlying biliary tract disease (54.1% versus 24.4%; p < .001) and have a community-acquired infection (62.2% versus 43.1%; p = .04) than those with K. pneumoniae BSIs. Intra-abdominal infection was the most common primary focus of infection. Biliary tract infection (64.9% versus 38.8%; p = .004) and pancreatitis (13.5% versus 3.8%; p = .03) were more common in patients with Raoultella BSIs. Raoultella isolates exhibited significantly higher susceptibility to aztreonam, cefepime, and cefotaxime. The 14-day and 30-day mortality rates were lower among the patients with Raoultella BSIs but did not differ significantly between groups (11% versus 22%; p = .16 and 11% versus 26%; p = .08 for Raoultella and K. pneumoniae BSIs, respectively). Conclusion: Raoultella spp. BSI more likely to occur in patients with underlying biliary tract disease and in community settings compared with K. pneumoniae BSIs. Biliary tract infection was the most common primary focus of Raoultella BSIs.