Raoultella terrigena infections in hematopoietic stem cell transplant recipients: High rate of mortality in multidrug-resistant strains - A retrospective observational study

Background: Raoultella terrigena is a Gram-negative bacterium mainly reported as aquatic and soil organism. It is rarely involved in human infections. This study investigated the epidemiology of R. terrigena infections in the National Bone Marrow Transplant Center of Tunis (NBMTC) between January 2010 and March 2018, their associated antibiotics resistance patterns, and the molecular features of extended-spectrum β-lactamase (ESBL) producing strains. Materials and Methods: Our retrospective study concerned hematopoietic stem cell transplant (HSCT) adult recipients hospitalized at the NBMTC and infected with R. terrigena. The search of the ESBL and carbapenemases genes for multidrug-resistant strains was performed by PCR amplification. Results: Twelve strains of R. terrigena were responsible for infections in 10 hematopoietic stem cell transplant recipients (1.2% of total HSCT recipients). They were responsible for skin (n = 4) and urinary tract infections (n = 4). The first-line antibiotherapy was based on a monotherapy in one case and a dual therapy in eleven cases. Imipenem was the most prescribed antibiotic (n = 7/12). Mortality was attributable to R. terrigena infection in two over ten patients. Nine strains were producing ESBL. Five strains were resistant to ertapenem, two to imipenem, ten to ciprofloxacin, and five to amikacin. BlaCTX-M1, blaOXA-48, and blaKPC were found in seven, four, and one strains, respectively. Conclusion: Low prevalence of R. terrigena infections in HSCT recipients but high rates of attributable mortality and multidrug-resistant strains.