Detection of Listeria monocytogenes in Humans, Animals and Foods.

Abstract

ABSTRACT. The Listeria monocytogenes-carrying rates were 100% for listeriosis patients and 1.3% for healthy humans. The L. monocytogenes contamination rates for retail sliced beef (34.2%) and pork (36.4%) were significantly higher (p<0.05) than those for cattle (2.0%) and pigs (0.8%) and for cattle (4.9%) and swine (7.4%) carcasses. The percentages of serotypes 1/2a, 1/2b and 4b which are most dominant in human patients were high in isolates from fresh (90.0%) and processed (100%) fish and shellfish and imported natural cheese (96.7%). -KEY WORDS: Listeria monocytogenes, meat, serotype J. Vet. Med. Sci. 60(12): 1341-1343, 1998 A 1-g portion of stool and intestinal content samples was enriched in 9 ml UVM medium (Difco Laboratories, Detroit, Mich.) or EB medium (Difco). The swabs were each added to 9 ml of an enrichment medium. Samples of natural cheese (25 g) and meat and fresh and processed seafoods (10 g each) were each placed in a stomacher bag containing 225 ml or 90 ml of the enrichment medium, and homogenized for 1 min with a stomacher. The stomacher bags were incubated at 30°C for 48 hr. Two to three loopfuls of the cultured enrichment medium from the stomacher bags were streaked on a plate of Oxford agar medium (Oxoid, Unipath Ltd., Basingstoke, Hampshire, England) or PALCAM agar medium (Merck Co., Inc., Rahway, N.J.) supplemented with amphotericin B (Sigma Chemical Co., St. Louis, Mo.) at a concentration of 6 µg/ml to inhibit the growth of mycetes and the plates were incubated at 30°C for 48 hr. Slightly flat colonies with brownish color in the periphery, which is characteristic of Listeria, were subcultured on Tryptose Agar medium (Difco). The colonies developed on Tryptose Agar medium were observed under a low power microscope with obliquely reflected light and blue greenish colonies were selected [12]. Identification was carried out by Gram staining, catalase and VP tests, observation of umbrella-like growth and motility in semiliquid Brain Heart Infusion Agar medium (Difco), utilization of rhamnose, xylose and mannitol, β-hemolysis on 5% sheep blood Tryptic Soy Agar medium (Difco) and the CAMP test [12] with Staphylococcus aureus JTE 88-221 and Rhodococcus equi JTE 89-387 .The factor sera were prepared by hyperimmunizing rabbits (Japan Laboratory Animals, Inc., Tokyo) with each of 12 reference strains, L. monocytogenes JTE 88-178 to JTE , by the method of Seeliger and Höhne [11]: 11 kinds of somatic (O) antigen factor sera and four kinds of flagellum (H) antigen factor sera were obtained. Serotyping was conducted by O and H agglutination reactions on microplates [1]. Description of the serotypes of the isolates was followed after Seeliger and Höhne [11].As shown in Table 1, the L. monocytogenes-carrying rates

Isolation of Listeria monocytogenes from the Skin of Slaughtered Beef Cattle

“…Isolation of L. monocytogenes from foods and animal stool samples has been reported in some countries [1]. A previous study reported isolation of L. monocytogenes from cow stools, carcasses and meat products, and suggested that feces was the most likely source of contamination of the carcasses [3]. The pathogen has also been isolated from environments such as slaughterhouses and sewage, sludge and food-processing plants [4,8,9].…”

Listeriosis in a Raccoon Dog (Nyctereutes procyonoides) Associated with Canine Distemper.

“…The infection, especially caused by Listeria monocytogenes, has been most frequently reported in cattle, sheep and goat, and less frequently in pigs and horses [8,15]. The pathogen has been isolated from healthy animals such as rats, cattle, dogs and pigs for reasons of public health concern [2,3,5,6]. There have been also some reports on the infection in wild animals, in over 30 species [4].…”

“…Whereas, Listeria monocytogenes is often isolated from healthy animals [2,3] as well as natural environments, listeriosis is regarded as a opportunistic infection which requires certain predisposing factors. In this case, it is suspected that the canine distemper virus infection acted as a predisposing factor for listeriosis.…”

Infecção natural por Listeria monocytogenes em cobaios Cavia porcellus

“…A L. monocytogenes pode causar infecção localizada severa ou generalizada em humanos e em uma grande variedade de vertebrados domésticos ou selvagens (IIDA et al, 1998;VÁSQUEZ-BOLAND et al, 2001). As formas clínicas incluem infecção do útero gestante e aborto, septicemia com abscessos viscerais miliares e meningite e/ou encefalite (LECUIT, 2007;MAXIE & YOUSSEF, 2007).…”