Listeria monocytogenes infection in inflammatory bowel disease patients: case series and review of the literature.

BACKGROUND: Listeria monocytogenes (LM) is a gram-positive intracellular bacillus that in immunodeficient patients, children, geriatric patients, pregnant women, and even in healthy individuals can cause central nervous system infection, bacteremia, and other clinical manifestations, becoming a relevant pathogen.
MATERIALS AND METHODS: From the Microbiology Service data of 'Gregorio Marañón' Hospital, we selected all positive biological sample cultures for LM from inflammatory bowel disease (IBD) patients, from January 1986 until January 2011. These cases were included in an SPSS database, analyzing several basal clinical characteristics and factors related to the infection.
RESULTS: Three patients diagnosed with IBD had positive cultures for LM during this period. All of them were male, and also all of them had a diagnosis of Crohn's disease. Every patient had a corticosteroid cumulated dose of more than 400 mg (equivalency in methylprednisolone doses), adding anti-tumor necrosis factor-α treatment (certolizumab) in one patient. Prior colonoscopy with biopsy was performed in two patients. Clinical presentation of the infection was bacteremia in two patients, accompanied by central nervous system infection in one patient. One patient had isolated meningoencephalitis. Despite correct empiric treatment, one patient died from a cause related to the infection, that is, rombencephalitis. Increased incidence of LM bacteremia was found in IBD patients, compared with the general population (12.2 bacteremias/100 000 IBD patient-years, compared with 1.6 bacteremias/100 000 person-years), with an odds ratio of 7.4.
CONCLUSION: IBD patients may be at risk for more frequent and serious LM infection compared with the general population.