pseudomonas bacteremia in liver transplant patients

In an approach to understanding the predisposition of this patient’s bowel injury to the development of an abscess, the clinical entity of neutropenic enterocolitis offers some insights. In that condition, the fundamentally important elements include intestinal mucosal injury that is followed by a degree of immune dysregulation. These lead to intestinal edema, engorged vessels, and a disrupted mucosal surface that is more vulnerable to bacterial intramural invasion. P aeruginosa bacteremia is a common problem in liver transplant recipients, with incidence as high as 11.4%. A retrospective study of 222 consecutive liver transplant recipients found that the main focus of Pseudomonas species bacteremia was the biliary tract. With the ischemia that this patient experienced at the site of his duodenal ulcer perforation, along with the translocation that occurred because of his likelihood of colonization with P aeruginosa on the basis of his liver transplant, it is understandable how a P aeruginosa abscess could develop in his bowel wall at the site of the surgical anastomosis. With the associated impairment of blood supply to that area and the resultant lack of adequate antibiotic delivery, pharmacological cure of the infection seems unlikely, and the abscess could continue to proliferate and seed the bloodstream to cause recurrent bacteremia as seen in this case. This patient developed massive bacteremia with endotoxemia, leading to the inflammatory pulmonary edema that the patient developed. On postmortem exam, an abscess in the intestinal wall extending across the anastomotic site was found and was the form of inadequate source control not identified on imaging but that led to the recurrent bacteremia (choice A is correct).12345

A 46-year-old man who received a liver transplantation 2 years ago for nonalcoholic steatohepatitis presented to the hospital 3 weeks ago with fever and intractable vomiting. On evaluation, he had an acute abdomen and was taken to the operating room, where he was found to have a perforated duodenal ulcer with surrounding tissue necrosis; 5 cm of his small bowel was resected, and he had a primary reanastomosis. The central venous catheter placed at the time of surgery was retained. Because of problems with urinary retention, a bladder catheter remained in place postoperatively. The patient remained in the hospital over the next week because of persistent ileus and inability to take in food orally. One week postoperatively, he began having recurrent temperature elevations to 39.1°C in association with shortness of breath. He had no symptoms related to his urinary tract. Workup at that time included a chest radiograph that showed basilar volume loss consistent with atelectasis. An abdominal CT scan showed thickening in the bowel wall at the site of the anastomosis. Urinalysis revealed 25 WBCs per high-power field. Blood cultures were drawn through both a peripheral vein and his central venous catheter, and both subsequently grew carbapenem-sensitive Pseudomonas aeruginosa. Meropenem was started empirically, and the central venous catheter was removed. Over the next 3 days, the patient continued to be febrile. Repeat blood cultures on days 2, 3, and 5 after antibiotics were started continued to be positive for P aeruginosa that remained sensitive to meropenem. On antibiotic day 7, the patient became acutely ill with fever, hypotension, and marked shortness of breath. He was transferred to the ICU, where his radiograph was interpreted as being consistent with ARDS. One hour later, his BP dropped to 82/44 mm Hg, and he was not responsive to 4 L of fluids. Based on this clinical course, what is the most likely explanation for this patient’s recurrent P aeruginosa bacteremia?

Footnotes

  1. SEEK Questionnaires ↩

  2. Alqarni A, Kantor E, Grall N, et al. Clinical characteristics and prognosis of bacteraemia during postoperative intra-abdominal infections. Crit Care. 2018;22(1):175. PubMed ↩

  3. Liu T, Zhang Y, Wan Q. Pseudomonas aeruginosa bacteremia among liver transplant recipients. Infect Drug Resist. 2018;11:2345-2356. PubMed ↩

  4. Parkins MD, Gregson DB, Pitout JD, et al. Population-based study of the epidemiology and the risk factors for Pseudomonas aeruginosa bloodstream infection. Infection. 2010;38(1):25-32. PubMed ↩

  5. Rodrigues FG, Dasilva G, Wexner SD. Neutropenic enterocolitis. World J Gastroenterol. 2017;23(1):42-47. PubMed ↩