INTRAVENOUS CENTRAL CATHETER COLONIZATION BY SHEWANELLA PUTREFACIENS IN A BURNED PATIENT.

Abstract

Shewanella putrefaciens is an opportunistic pathogen rarely responsible for human infection. However, it has been reported that it causes skin and soft tissue infections and bacteremia in immune-compromised patients, such as cellulitis, abscesses, bacteremia, and wound infection. It is an oxidase and catalase-positive non-fermenter gram-negative rod that produces hydrogen sulfide. We report the case of a 90-year-old woman, who presented an invasive infectious burn wound associated with Shewanella putrefaciens bacteremia. She was admitted into the burn center of the military hospital M.S Nekkache of Algiers, suffering from 40% TBSA with a history of diabetes. After one week of admission, the patient complained of a high fever. Microbiological culture of the catheter tip was positive and showed pale colonies on the MacConkey agar, non-lactose fermenting plate. Nutritive agar medium culture showed red pale tan colonies with a concentration >10³ CFU. Identification and antibiotic susceptibility were obtained by the Phoenix system (Becton-Dickinson, USA) as Shewanella putrefaciens. This was confirmed by standards and semi-automated microbiological techniques. Gram stain showed Gram-negative bacilli with positive oxidase and catalase reactions. Production of hydrogen sulfide was confirmed by the semi-automated API 20NE method (biomerieux, France). The isolate was resistant to gentamicin, amikacin, ceftazidime, aztreonam, amoxicillin- clavulanic acid, cefepime, trimethoprim/sulfamethoxazole, and nitrofurantoin. In our case, S. putrefaciens was found in a mixed culture with Klebsiella pneumoniae. No earlier exposure of the patient to marine water had been noticed. Blood culture indicated colonies growth of Acinetobacter baumannii. No further isolation of this bacteria was noticed after treatment. The patient was given imipenem, vancomycin and colistin. Despite our best efforts, the patient could not be saved because of sepsis and renal function failure.