Virulence of Listeria monocytogenes Serovars and Listeria spp. in Experimental Infection of Mice

Wild strains of Listeria monocytogenes, Listeria ivanovii, Listeria seeligeri, Listeria innocua, and Listeria welshimeri were isolated from infected animals and foodstuffs. Their virulence was tested in Swiss mice after intraperitoneal injection of a fixed number of organisms. The presence of hemolysin was determined using the CAMP test. Bacteria were enumerated in peritoneal lavage fluid, liver, and spleen. Spleen weights were measured, and the presence of L. monocytogenes in the brain was also investigated. L. innocua, L. seeligeri, and L. welshimeri were not found to be pathogenic for mice. L. ivanovii was detected in liver, spleen, and peritoneal lavage fluid but at lower levels than L. monocytogenes (p<0.001). The pathogenic capabilities of four different serovars of L. monocytogenes (4b, 1/2a, 1/2b, 1/2c) were compared. Serovars l/2b and l/2c, which are frequently isolated from foodstuffs, were found to colonize the liver and spleen to a lesser extent than serovar 4b (p<0.01 and <0.001 respectively). The behavior of serovar l/2a, the most commonly isolated from foodstuffs, was strain dependent. Two out of the four strains tested were strongly hemolytic and were as virulent as strains of serovar 4b, while the other two were weakly hemolytic, and avirulent like L. innocua. These results could account for the relatively small number of human Listeria infections due to L. monocytogenes serogroup 1/2, despite the very frequent occurrence of this serovar in foodstuffs.

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Monoclonal Antibodies Directed Against the Flagellar Antigens of Listeria Species and Their Potential in EIA-Based Methods

Journal of Food Protection ◽

10.4315/0362-028x-50.6.479 ◽

1987 ◽

Vol 50 (6) ◽

pp. 479-484 ◽

Cited By ~ 38

Author(s):

JEFFREY M. FARBER ◽

JOAN I. SPEIRS

Keyword(s):

Staphylococcus Aureus ◽

Monoclonal Antibodies ◽

Listeria Monocytogenes ◽

Enzyme Immunoassay ◽

Listeria Innocua ◽

Milk Samples ◽

Listeria Ivanovii ◽

Flagellar Antigen ◽

Listeria Seeligeri ◽

Listeria Welshimeri

Monoclonal antibodies directed against antigens of Listeria spp. were produced. Three main classes of immunoglobulins were found that reacted with Listeria strains containing either the A, B, or C flagellar antigen. These antibodies reacted with Listeria monocytogenes, Listeria welshimeri, Listeria seeligeri, Listeria ivanovii and Listeria innocua, but not Listeria grayi, Listeria murrayi or Listeria denitrificans. The monoclones tested did not cross-react with any of the 30 non-Listeria cultures examined, including Staphylococcus aureus and Streptococcus faecalis. Cheese and milk samples naturally-contaminated with L. monocytogenes were found to be positive for Listeria within two working days after initiation by using the monoclonal antibodies in an enzyme immunoassay.

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Listeria Species in Raw and Ready-to-Eat Foods from Restaurants

Journal of Food Protection ◽

10.4315/0362-028x-64.4.551 ◽

2001 ◽

Vol 64 (4) ◽

pp. 551-553 ◽

Cited By ~ 32

Author(s):

J. M. SORIANO ◽

H. RICO ◽

J. C. MOLTÓ ◽

J. MAÑES

Keyword(s):

Listeria Monocytogenes ◽

Listeria Innocua ◽

Listeria Species ◽

Listeria Ivanovii ◽

Listeria Seeligeri ◽

Listeria Welshimeri

From September 1999 to March 2000, meat (pork, beef, and chicken), fish (salmon, hake, and sole), vegetable (lettuce and spinach), and Spanish potato omelette samples obtained at restaurants were collected and tested for the occurrence of Listeria spp. Listeria monocytogenes was isolated from 3 (2.9%) out of 103 studied samples. Other species isolated were Listeria grayi (13.6%), Listeria innocua (1.9%), Listeria ivanovii (5.8%), Listeria seeligeri (3.9%), and Listeria welshimeri (1.9%). Listeria was neither isolated from beef nor any type of fish.

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Isolation de micro-organismes du genre Listeria à partir de lait cru destiné à la consommation humaine

Canadian Journal of Microbiology ◽

10.1139/m85-176 ◽

1985 ◽

Vol 31 (10) ◽

pp. 938-941 ◽

Cited By ~ 33

Author(s):

Lucas Domínguez Rodriguez ◽

Jose F. Fernández Garayzabal ◽

Jose A. Vazquez Boland ◽

Elias Rodriguez Ferri ◽

Guillermo Suarez Fernández

Keyword(s):

Listeria Monocytogenes ◽

Raw Milk ◽

Listeria Innocua ◽

Central Spain ◽

Listeria Ivanovii ◽

Lait Cru ◽

Listeria Seeligeri ◽

Listeria Welshimeri

Refrigerated mixtures of raw milk provided by a dairy which was supplied by farms from west and central Spain were tested for the presence of Listeria microorganisms. A total of 95 samples were taken at regular intervals over a 16-month period. Listeria grayi was isolated from 89.5% of the samples, Listeria monocytogenes s. str. from 45.3%, Listeria innocua from 15.8%, Listeria welshimeri from 3.1%, and Listeria seeligeri from 1.05%. Listeria ivanovii, Listeria murrayi, and Listeria denitrificans were not isolated.[Translated by the journal]

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Incidence of Listeria monocytogenes and other Listeria spp. in Ewes' Raw Milk

Journal of Food Protection ◽

10.4315/0362-028x-57.7.571 ◽

1994 ◽

Vol 57 (7) ◽

pp. 571-575 ◽

Cited By ~ 21

Author(s):

JOSE L. RODRIGUEZ ◽

PILAR GAVA ◽

MARGARITA MEDINA ◽

MANUEL NUÑEZ

Keyword(s):

Listeria Monocytogenes ◽

Sampling Period ◽

Raw Milk ◽

Seasonal Influence ◽

Listeria Ivanovii ◽

Milk Contamination ◽

One Year ◽

The One ◽

Listeria Seeligeri ◽

Listeria Welshimeri

Ewes' milk samples from 287 farm bulk tanks and 17 transport tankers were analyzed for Listeria over a one-year period. Listeria monocytogenes and Listeria innocua were detected in 2.19% and 2.00% of 1052 farm samples, and in 18.38% and 11.76% of 136 tanker samples, respectively. Incidence of Listeria grayi, Listeria ivanovii, Listeria seeligeri and Listeria welshimeri was under 0.4% in farm samples and under 1% in tanker samples. Most farms (93.38%) produced milk free from L. monocytogenes throughout the one-year sampling period. No seasonal influence on milk contamination by Listeria was found. However, ewes' milk contamination by L. monocytogenes and other Listeria spp. was significantly higher in farms where cows were also reared than in farms where only ewes were present.

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Prevalence and Contamination Levels of Listeria monocytogenes in Smoked Fish and Pâté Sold in Spain

Journal of Food Protection ◽

10.4315/0362-028x-64.12.2075 ◽

2001 ◽

Vol 64 (12) ◽

pp. 2075-2077 ◽

Cited By ~ 26

Author(s):

C. DOMINGUEZ ◽

I. GOMEZ ◽

J. ZUMALACARREGUI

Keyword(s):

Listeria Monocytogenes ◽

Listeria Innocua ◽

Smoked Fish ◽

Listeria Ivanovii ◽

Retail Outlets ◽

Contamination Levels ◽

Listeria Seeligeri ◽

Listeria Welshimeri

From March to November 2000, 170 samples of smoked fish and 182 samples of pâté for sale in retail outlets and supermarkets in the nine provinces of Castilla and León (Spain) were analyzed for the prevalence of Listeria monocytogenes and other Listeria spp. L. monocytogenes was isolated from 38 (22.3%) of the 170 samples of smoked fish analyzed. Twenty of these positive samples contained L. monocytogenes at >100 CFU/g. Other Listeria spp., such as Listeria innocua (26 isolates), Listeria grayi (9), Listeria welshimeri (3), Listeria seeligeri (3), and Listeria ivanovii (2), were also detected. L. monocytogenes was isolated from 5.4% of the 182 samples of pâté. Only 1 of the 10 positive samples harbored >100 L. monocytogenes CFU/g. Two other species of Listeria were observed in pâté: L. innocua (12 isolates) and L. grayi (2).

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Surveillance for Contamination of Salad with Listeria Monocytogenes in Some of Baghdad Restaurants

AL-Kindy College Medical Journal ◽

10.47723/kcmj.v15i2.151 ◽

2020 ◽

Vol 15 (2) ◽

pp. 4-8

Author(s):

Ilham Abid Fathi

Keyword(s):

Listeria Monocytogenes ◽

International Standards ◽

Listeria Innocua ◽

Health Conditions ◽

Routine Examination ◽

Listeria Ivanovii ◽

International Standards Organization ◽

Listeria Seeligeri ◽

Listeria Welshimeri ◽

Different Levels

Background: Listeria monocytogenes, a member of the genus Listeria, is widely distributed in agricultural environments, such as soil, manure and water. The genus of Listeria bacteria is about 15-17 species. It is a pathogenic bacterium that can cause a rare but dangerous infection called listeriosis. Objectives: Studying the rate of salads contaminated with Listeria bacteria. and Listeria monocytogenes according to International, Arabic and Iraqi specifications and finding the correlation between commitments of restaurants to standard health conditions with contamination with these bacteria Methods: The study included 152 samples of salads taken from 39 restaurants chosen randomly and of different levels and places in Baghdad from the period between 1/9/2014 to 20/1/2015. The laboratory tests were carried out on samples based on internationally approved methods in addition to methods of the International Standards Organization. Results: The study revealed that 23 samples (15.13%) from the 152 samples taken from the restaurants were contaminated with Listeria species. of these, 3 (2%) were contaminated with Listeria monocytogenes and 20 (13.2%) were contaminated with other types of different and non-pathogenic Listeria as follows; (Listeria welshimeri, Listeria seeligeri, Listeria ivanovii, Listeria grayi, Listeria innocua) with the following prevalence (7(4.6%), 6(3.9%), 3(2%), 3(2%), 1 (0.7%) respectively). Conclusions: Contamination of salads taken from restaurants with Listeria bacteria is not uncommon. This indicates that routine examination is necessary and should be added to the Iraqi standard for salads.

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Role and Regulation of Adipokines during Zymosan-Induced Peritoneal Inflammation in Mice

Endocrinology ◽

10.1210/en.2008-0327 ◽

2008 ◽

Vol 149 (8) ◽

pp. 4080-4085 ◽

Cited By ~ 20

Author(s):

Maria Pini ◽

Melissa E. Gove ◽

Joseph A. Sennello ◽

Jantine W. P. M. van Baal ◽

Lawrence Chan ◽

...

Keyword(s):

Inflammatory Infiltrate ◽

Peritoneal Lavage ◽

Lavage Fluid ◽

Wild Type ◽

Cellular Infiltrate ◽

Peritoneal Lavage Fluid ◽

Peritoneal Inflammation ◽

Leptin Deficiency ◽

Cytokine Levels

Adipokines, cytokines mainly produced by adipocytes, are active participants in the regulation of inflammation. Administration of zymosan (ZY) was used to investigate the regulation and role of adipokines during peritonitis in mice. Injection of ZY led to a significant increase in leptin levels in both serum and peritoneal lavage fluid, whereas a differential trend in local vs. systemic levels was observed for both resistin and adiponectin. The role of leptin in ZY-induced peritonitis was investigated using leptin-deficient ob/ob mice, with and without reconstitution with exogenous leptin. Leptin deficiency was associated with delayed resolution of peritoneal inflammation induced by ZY, because ob/ob mice had a more pronounced cellular infiltrate in the peritoneum as well as higher and prolonged local and systemic levels of IL-6, TNFα, IL-10, and chemokine (C-X-C motif) ligand 2 compared with wild-type mice. Reconstitution with exogenous leptin exacerbated the inflammatory infiltrate and systemic IL-6 levels in ob/ob mice while inhibiting production of TNFα, IL-10, and chemokine (C-X-C motif) ligand 2. In contrast with the important role of leptin in regulating each aspect of ZY-induced peritonitis, adiponectin deficiency was associated only with a decreased inflammatory infiltrate, without affecting cytokine levels. These findings point to a complex role for adipokines in ZY-induced peritonitis and further emphasize the interplay between obesity and inflammation.

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