Abstract:Objective To investigate the clinical characteristics of patients with Klebsiella variicola (K. variicola) infection, and provide theoretical basis for the prevention and control of the pathogen in clinical practice. Methods 70 patients infected with K. variicola identified by whole-genome sequencing in a hospital between January 2013 and July 2018 were collected retrospectively. 70 patients with Klebsiella pneumoniae (K. pneumoniae) infection during the same period were randomly selected as control. Clinical data of two groups were analyzed. Results 70 patients with K. variicola infection were aged 1 day-95 years, median age was 51 years old, 6 (8.6%) of whom were infants less than 1 year old. The underlying diseases were mainly cardiovascular diseases (16, 22.9%), followed by diabetes mellitus (11, 15.7%) and tumor (9, 12.6%). The main infection sites were respiratory system (34, 48.6%), blood stream (8, 11.4%) and intra-abdominal cavity (8, 11.4%). 20 patients (28.6%) were with low or suppressed immunity due to tumor radio-/chemotherapy, glucocorticoid or immunosuppressive therapy. Resistance rates of K. variicola to commonly used antimicrobial agents were low (all < 40%), and lower than that of K. pneumoniae (all P < 0.001). Conclusion Clinical characteristics of patients with K. variicola infection are similar to patients with K. pneumoniae infection. It is necessary to be alert to the epidemic transmission of this bacteria in infants and population with low immunity. At present, antimicrobial resistance rate of K. variicola is low, but it is still necessary to standardize clinical rational use of antimicrobial agents, so as to prevent the emergence of antimicrobial resistant strains.