A Case of Plesiomonas Bacteremia Without Reported Freshwater Exposure

Plesiomonas shigelloides is a member of the Enterobacteriaceae family generally found in freshwater. There is little substantive data about the prevalence or distribution of Plesiomonas within the United States. Plesiomonas are most commonly associated with mild, self-limited watery diarrhea among healthy individuals followed by infective colitis. Bacteremia is the most common extraintestinal manifestation of Plesiomonas. Few cases of Plesiomonas bacteremia can be found in the literature.

An elderly female with multiple comorbidities was admitted to our hospital for evaluation of generalized cramping abdominal pain of several days duration. She denied any freshwater or saltwater exposure. The patient's labs were significant for leukocytosis and lactic acidosis. An abdominopelvic CT showed acute colitis of the descending colon.

Surgery was consulted for suspicion of ischemic colitis, and the patient subsequently underwent subtotal colectomy, splenectomy and resection of the distal small bowel with an ileostomy, as extensive necrotic bowel was found. Blood cultures taken on admission grew Plesiomonas shigelloides, for which piperacillin-tazobactam was started. Negative blood cultures were obtained 4 days after positive blood cultures.

Relative rarity and variability of presentation, presence or absence of underlying disease or exposure to risk factors, and currently limited data utilizing different antimicrobial regimens contribute to the difficulty in outlining guideline-based regimens for management of Plesiomonas.