Citrobacter youngae nosocomial bacteremia from postoperative pyogenic spondylodiscitis after a minimally invasive spinal surgery

Citrobacter youngae (C. youngae) was first described in 1993, and data suggesting that human diseases caused by this bacterium remain scarce. Reports on C. youngae infections mostly described local infections without evidenced bacteremia, especially in immunocompromised patients. Herein, we report a rare case of bacteremia with intervertebral disc and adjacent vertebral infection due to C. youngae (detected by the Vitek^® 2 Compact). A 70-year-old man with chronic lower back pain due to lumbar disc herniation underwent microdiscectomy, a minimally invasive spinal surgery. On postoperative day 4, he suffered shaking chills with worsened lower back pain compared to that before the operation, and vancomycin plus ceftriaxone were empirically administered. Magnetic resonance imaging (MRI) of the lumbar spine revealed osteomyelitis at L4 and L5 with L4/L5 discitis. Two blood culture sets were positive with the same pathogen, possibly C. youngae; The patient was then treated successfully with ceftazidime plus ciprofloxacin, the antibiotics were selected based on antibiotic susceptibility test results. This report suggests that C. youngae may cause severe infections in immunocompetent patients, and further surveillance should be considered to monitor antibiotic-resistant bacteria.