Isolation of Listeria monocytogenes in neural forms of listeriosis and abortions in ruminants

Abstract

L. monocytogenes is a food borne pathogen capable of causing serious invasive diseases in humans and animals, including abortion, septicemia, meningitis and meningoencephalitis. Isolation of the agent is the most accurate diagnostic method in all situations of suspected L. monocytogenes infection. Direct isolation of L. monocytogenes is relatively simple in cases when the number of organisms is very large, such as septicaemic disease forms. Isolation is quite difficult if the agent is present in very small quantities, such as in encephalitis, or if the sample is highly contaminated. In this paper we presented the isolation of L. monocytogenes from clinical samples by using selective media for enrichment and isolation, combined with the cold enrichment technique. In our investigation we isolated L. monocytogenes from 18 of the total of 46 investigated tissue samples originating from animals with clinical diagnosis of listeriosis. We also presented the basic differential-diagnostic procedure in relation to the mimicking bacterial species.