Septic Shock Caused by Rahnella aquatilis Bacteremia in an Immunocompetent Adult

BACKGROUND Rahnella aquatilis is a facultatively anaerobic, gram-negative rod bacterium commonly found in freshwater. There are few cases of bacteremia caused by Rahnella aquatilis in the literature and even fewer cases reported of it causing sepsis in immunocompetent individuals. In this case report, we present a rare case of an immunocompetent individual who developed sepsis secondary to bacteremia caused by Rahnella aquatilis. CASE REPORT A 37-year-old immunocompetent man with cerebral palsy and chronic enterocutaneous fistulas, with an indwelling peripherally inserted central catheter (PICC) line for total parenteral nutrition (TPN), presented to the emergency department with complaints of increased enteric drainage from his fistula, rigors, and subjective fevers following a mechanical fall, which occurred approximately 1 week before. The day following admission, the patient developed septic shock and was transferred to the intensive care unit for vasopressor support. He was given intravenous cefepime and metronidazole for empiric therapy. Blood cultures grew Rahnella aquatilis, and antibiotic therapy was de-escalated to monotherapy with intravenous ceftriaxone. The patient's condition stabilized, his PICC line was replaced, and he was successfully discharged, and continued on outpatient antibiotic therapy with ceftriaxone. CONCLUSIONS This case report represents a novel presentation of septic shock secondary to bacteremia caused by a gram-negative rod bacterium, Rahnella aquatilis, in an immunocompetent host dependent on TPN via a PICC line. This case also demonstrates that Rahnella aquatilis can be susceptible to and treated successfully with intravenous ceftriaxone. Bacteremia caused by Rahnella aquatilis can cause a swift, aggressive decompensation and should be treated with antibiotics immediately.