Intra-abdominal abscess caused by Listeria monocytogenes in a patient with acquired hemolytic anemia and thrombocytopenia.

ABSTRACT: We report a case of an intra-abdominal abscess caused by Listeria monocytogenes in a postoperative patient with Evans syndrome (acquired hemolytic anemia and thrombocytopenia). Focal infections with L monocytogenes are uncommon but have been reported in immunocompromised patients. A few cases of liver abscess in diabetic patients have also been reported. The present case is significant because of the paucity of previously described focal intra-abdominal infections caused by L monocytogenes, particularly as a postsplenectomy pathogen.

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LISTERIA MONOCYTOGENES is a gram-positive facultative intracellular bacterium that infects phagocytic and nonphagocytic cell lines. It is well described as a cause of meningitis in the elderly and in immunocompromised patients. Sepsis due to Listeria sp is not uncommon in patients with alcoholism or other immunodeficiency states. (1) A few cases of liver abscess caused by L monocytogenes have been reported in diabetic patients, (2) but the organism rarely causes abdominal infections.

CASE REPORT

One month after resection of an accessory spleen, a 40-year-old woman came to the emergency room with a 4-day history of increasing abdominal discomfort localized to the left flank, shaking chills, and nausea. Her medical history was significant for idiopathic thrombocytopenic purpura and autoimmune hemolytic anemia (Evans syndrome) diagnosed 2 years earlier. She was treated with prednisone, gamma globulin, dexamethasone, danazol, and vincristine for several months. One year after diagnosis, laparoscopic splenectomy was done for refractory anemia and thrombocytopenia. The patient was in her usual state of health until 1 month before this presentation when she had epistaxis with decreasing platelet counts. A liver-spleen scan showed an accessory spleen, and distal pancreatectomy with resection of the accessory spleen was done at that time. The gross pathology specimen was a 3.0 x 3.0 x 1.8 cm accessory spleen without any obvious lesions. The sections submitted for histologic analysis showed fibrosis, calcifica tion, and rare noncaseating granulomas of the capsule and hemosiderin deposition consistent with previous surgery and/or inflammation. Her medications included vincristine every 1 or 2 weeks and danazol 200 mg twice daily.

Physical examination at the time of admission revealed an African American woman with a temperature of 102[degrees]F, pulse rate 129/mm, blood pressure 105/70 mm Hg, and oxygen saturation 99% on room air. She was flushed but not icteric. The neck was supple without adenopathy. Crackles were heard at the left lung base, and abdominal examination revealed left upper quadrant fullness and tenderness. Laboratory values included a white blood cell (WBC) count of 39,000/[mm.sup.3] with 54% polymorphonuclear leukocytes, 6% band forms, 20% lymphocytes, and 20% monocytes; hemoglobin 10.4 g/dL, hematocrit 31.3%, and platelet count 120,000/[mm.sup.3]. Results of other laboratory studies including liver and renal function tests and measurements of electrolytes, amylase, and lipase were within normal limits. Computed tomography (CT) of the abdomen with and without contrast medium revealed a large fluid collection with a thin enhancing wall in the splenic resection bed measuring 9 x 7 cm in the transverse plane and 11 cm c raniocaudally (Figure). The patient was initially treated with intravenous metronidazole and cefazolin. Twenty-four hours after admission, under CT guidance, the fluid collection was drained of approximately 500 mL of purulent material. Gram stain showed rare neutrophils and rare gram-positive cocci in pairs. After 48 hours, culture of the intra-abdominal abscess fluid grew many L monocytogenes organisms that were found to be sensitive to ampicillin. No other organisms were recovered.

Two sets of blood cultures were negative. The patient was treated with intravenous ampicillin-sulbactam, and fever rapidly resolved. She completed a 4-week course of antibiotics and has remained well.

DISCUSSION

Listeria monocytogenes is a gram-positive facultative intracellular bacterial pathogen that infects phagocytic and nonphagocytic cell types. It has a propensity to infect the reticuloendothelial system and specifically targets macrophages, where it replicates and survives. The main route of transmission is via contaminated foods such as dairy products, vegetables, meats, and seafood; it is therefore considered a foodborne pathogen. (3) It has been identified in seafood and meat processing facilities. (4) Infection with L monocytogenes (listeriosis) has various clinical presentations in humans. It has been known to cause disease in neonates, pregnant women, elderly people, and immunocomprised adults with T-cell mediated immune dysfunction such as those with diabetes, leukemia, acquired immunodeficiency syndrome, Hodgkin's disease, alcoholism, systemic lupus erythematosus, and transplant recipients. (2,5) Listeriosis has been associated with a mild influenza-like illness, meningitis, meningoencephalitis, septic emia, and bacteremia, but focal infections have been rare. In reviewing the literature, Ortel (1) found 2 cases of abscesses in diabetic patients, though the locations of the abscesses were not specified. In their case report, Adeonigbagbe et al (6) described spontaneous bacterial peritonitis caused by Listeria sp in a patient with cholangiocarcinoma and liver metastasis. They recognized that chronic liver disease and iron overload seem to be additional predisposing factors. Intra-abdominal abscess at the site of previous surgery has not been reported heretofore. Presumably, the intra-abdominal abscess in this patient could be attributed to a transient listerial bacteremia, which seeded her accessory spleen; then at the time of pancreatectomy, the organism infected her abdominal cavity. Although it has been a widely accepted view that disruption of the bowel wall during surgery, allowing release of gastrointestinal microorganisms into the peritoneal cavity, is a primary mechanism for peritonitis and abscess, (7) our patient did not have any recognizable bowel penetration during surgery. Since the blood cultures were negative for any growth and the patient had no symptoms or signs to suggest gastrointestinal invasion, one can theorize that the spleen with a high concentration of macrophages was the culprit.

In addition, listerial meningitis and peritonitis have been frequently associated with high monocyte counts, which can be used as a clue to the presence of the organism. (6,9) Our patient had a WBC count of 39,000/[mm.sup.3] with 20% monocytes.

We believe this is the first reported case of L monocytogenes causing intra-abdominal abscess at the site of a previous splenectomy. It suggests that L monocytogenes should be considered as a possible pathogen in cases of intra-abdominal abscess. The organism was sensitive to ampicillin, and the patient was treated with ampicillin-sulbactam because of the suspected presence of anaerobes. However, all other cultures remained negative, and the infection resolved with abscess drainage and antibiotic therapy.

References

(1.) Ortel S: Listeria-meningitis and -septicemi in immunocompromised patients. Acta Microbiol Hung 1989; 36:153-157

(2.) Lopez-Prieto MD, Aller Garcia AI, Alcaraz Garcia S, et al: Liver abscess due to Listeria monocytogenes. Clin Microbiol Infect 2000; 6:226-227

(3.) Pingulkar K, Kamat A, Bongirwar D: Microbiological quality of fresh leafy vegetables, salad components and ready-to-eat salads: an evidence of inhibition of Listeria monocytogenes in tomatoes. In J Food Sci Nutr 2001: 52:15-23

(4.) Huss HH, Jorgensen LV, Vogel BF: control options for Listeria monocytogenes in seafoods. In J Food Microbiol 2000; 62:267-274

(5.) Armstrong D: Listeria monocytogenes. Principles and Practice of Infectious Diseases. Mandell GL, Bennett JE, Dolen R (eds). New York, Churchill Livingstone, 4th Ed, 1995, pp 1880-1885

(6.) Adeonigbagbe O, Khademi A, Karowe M, et al: Listeria monocytogenes peritonitis: an unusual presentation and review of the literature. J Clin Gastroenterol 2000;30:436-437

(7.) Bosscha K, Nieuwenhuijs VB, Gooszen AW, et al: A standardised and reproducible model of intra-abdominal infection and abscess formation in rats. Eur J Surg 2000;166:963-967

(8.) Troxler R, Von Graevenitz A, Funke G, et al: Natural antibiotic susceptibility of Listeria species. Clin Microbiol Infect 2000;6:525-535

(9.) Davies RS, Burgin M: MRI appearances of Listeria rhombencephalitis, Aust Radiol 1996;40:354-356

RELATED ARTICLE: KEY POINTS

* A patient with Evans syndrome had an intra-abdominal abscess caused by Listeria monocytogenes.

* Listeria monocytogenes is an unusual cause of intra-abdominal infections.

* Our patient had had a resection of an accessory spleen for refractory thrombocytopenia. We speculate that the spleen became seeded by a transient primary bacteremia, which subsequently infected the abdominal cavity at the time of surgery.

From the Department of Medicine, Division of Infectious Disease, University of Tennessee College of Medicine, Memphis.

Reprint requests to John Norwood, MD, University of Tennessee College of Medicine, Division of Infectious Disease, Coleman Bldg, Room H-308, 956 Court Aye, Memphis, TN 38163.