DNA polymorphism in 35 Listeria monocytogenes strains belonging to serovars 1/2a, 1/2b, 1/2c, and 4b was studied by genomic DNA digestion. The restriction endonucleases ApaI and NotI, which cleave DNA at rare sequences, were used, and DNA fragments were analyzed by pulsed-field gel electrophoresis. Restriction fragment length polymorphism varied among different serovars and was used for epidemiological studies, but serovar 1/2c isolates could not be analyzed because their restriction patterns were indistinguishable. The genome sizes were calculated by addition of the sizes of the ApaI fragments and were found to be about 2,660 kb for serovar 1/2a strains, 2,640 kb for serovar 1/2b strains, and 2,710 kb for serovar 4b strains but only 2,340 kb for serovar 1/2c strains. This last group therefore appears to differ from the other serovar strains by the absence of restriction fragment length polymorphism and a chromosome that is 15% shorter, suggesting that strains of serovar 1/2c have quite recently emerged.
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http://dx.doi.org/10.1128/jcm.29.7.1351-1355.1991 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
November 2024
Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa. Electronic address:
Among the severe foodborne illnesses, listeriosis resulting from the pathogen Listeria monocytogenes exhibits one of the highest fatality rates. This study investigated the application of near infrared hyperspectral imaging (NIR-HSI) for the classification of three L. monocytogenes serotypes namely serotype 4b, 1/2a and 1/2c.
View Article and Find Full Text PDFTrop Anim Health Prod
February 2024
Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria, 0110, South Africa.
These cross-sectional studies reported the occurrence, genetic characteristics, and factors associated with the distribution of Listeria species on cattle farms and beef abattoirs in Gauteng Province, South Africa. A total of 328 samples (faeces, feeds, silage, and drinking water) were collected from 23 cattle farms (communal, cow-calf, and feedlot), and 262 samples (faeces, carcass swabs, and effluents) from 8 beef abattoirs (low throughput and high throughput) were processed using standard bacteriological and molecular methods to detect Listeria species. The factors associated with the prevalence of Listeria species were investigated, and multiplex polymerase chain reaction (mPCR) was used to determine Listeria species, the pathogenic serogroups, and the carriage of eight virulence-associated genes by Listeria monocytogenes.
View Article and Find Full Text PDFRev Argent Microbiol
December 2023
IGEVET - Instituto de Genética Veterinaria Ing. Fernando N. Dulout (UNLP-CONICET LA PLATA), Facultad de Ciencias Veterinarias, La Plata, Buenos Aires, Argentina.
Listeria monocytogenes is an opportunistic foodborne pathogen. It can resist stress conditions by adapting through the production of biofilms, which represents a serious problem for the food industry. It is classified into 14 serotypes, although only four (1/2a, 1/2b, 1/2c, and 4b) account for 89.
View Article and Find Full Text PDFFoodborne Pathog Dis
May 2023
Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, Ottawa, Ontario, Canada.
The Gram-positive bacterium causes a significantly high percentage of fatalities among human foodborne illnesses. Surface proteins, specifically expressed from a wide range of serotypes under selective enrichment culture conditions, can serve as targets for the isolation of this pathogen using antibody-based methods to facilitate molecular detection. In this study, monoclonal antibodies (MAbs), previously raised against the LPXTG surface proteins LMOf2365_0639 and LMOf2365_0148, were investigated for their ability to isolate from bacterial samples with immunomagnetic separation (IMS).
View Article and Find Full Text PDFInt J Food Microbiol
April 2023
Laboratory of Food Microbiology and Hygiene, Department of Food Science and Nutrition, School of the Environment, University of the Aegean, 81400 Myrina, Lemnos, Greece. Electronic address:
Listeria monocytogenes is a facultatively intracellular pathogenic bacterium that can provoke invasive listeriosis, a severe foodborne infection in humans. Outside the host, this is capable to survive for long periods in soil, and water, as well as on plants, while, like many other microorganisms, this can also attach to abiotic surfaces, such as food contact ones, forming biofilms on them. It has been suggested that inside those sessile communities, L.
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