Listeria

For the disease caused by Listeria see Listeriosis

Listeria
Scanning electron micrograph of Listeria monocytogenes.
Scientific classification
Kingdom:	Bacteria
Division:	Firmicutes
Class:	Bacilli
Order:	Bacillales
Family:	Listeriaceae
Genus:	Listeria Pirie 1940
Species
L. grayi L. innocua L. ivanovii L. monocytogenes L. seeligeri L. murrayi L. welshimeri

Listeria is a bacterial genus that contains seven species. Named after the English pioneer of sterile surgery Joseph Lister, the genus received its current name in 1940. Listeria species are gram-positive bacilli. The major human pathogen in the Listeria genus is L. monocytogenes. It is usually the causative agent of the relatively rare bacterial disease, listeriosis, a serious infection caused by eating food contaminated with the bacteria. The disease affects primarily pregnant women, newborns, adults with weakened immune systems, and the elderly.

Listeriosis is a serious disease for humans; the overt form of the disease has a mortality rate of about 20 percent. The two main clinical manifestations are sepsis and meningitis. Meningitis is often complicated by encephalitis, a pathology that is unusual for bacterial infections. Listeria ivanovii is a pathogen of mammals, specifically ruminants, and has rarely caused listeriosis in humans.^[1]

Background

The first documented case of Listeria was in 1924. In the late 1920s, two researchers independently identified Listeria monocyctogenes from animal outbreaks. They proposed the genus Listerella in honor of surgeon and early antiseptic advocate Joseph Lister; however, that name was already in use for a slime mold and a protozoan. Eventually, the genus Listeria was proposed and accepted. All species within the Listeria genus are Gram-positive, nonsporeforming, catalase-positive rods. The genus Listeria was classified in the family Corynebacteriaceae through the seventh edition of Bergey’s Manual of Systematic Bacteriology. The 16S rRNA cataloging studies of Stackebrandt, et al. demonstrated that L. monocytogenes is a distinct taxon within the Lactobacillus-Bacillus branch of the bacterial phylogeny constructed by Woese. In 2001, the genus was placed in the newly created Family Listeriaceae. The only other genus in the family is Brochothrix.^[2]

The genus Listeria currently contains seven species: L. grayi, L. innocua, L. ivanovii, L. monocytogenes, L. murrayi, L. seeligeri, and L. welshimeri. Listeria dinitrificans, previously thought to be part of the Listeria genus, was reclassified into the new genus Jonesia.^[3] Under the microscope, Listeria species appear as small, Gram-positive rods, which are sometimes arranged in short chains. In direct smears, they may be coccoid, so they can be mistaken for streptococci. Longer cells may resemble corynebacteria. Flagella are produced at room temperature, but not at 37 °C. Hemolytic activity on blood agar has been used as a marker to distinguish L. monocytogenes among other Listeria species, but it is not an absolutely definitive criterion. Further biochemical characterization may be necessary to distinguish between the different species of Listeria.

Listeria can be found in soil, which can lead to vegetable contamination. Animals are most common carriers. Listeria has been found in uncooked meats, uncooked vegetables, fruit such as cantaloupes,^[4] unpasteurized milk, foods made from unpasteurized milk, and processed foods. Pasteurization and sufficient cooking kill Listeria; however, contamination may occur after cooking and before packaging. For example, meat-processing plants producing ready-to-eat foods, such as hot dogs and deli meats, must follow extensive sanitation policies and procedures to prevent Listeria contamination. Once an infection occurs in humans, one out of five people die. Once the infection begins in a processing plant, it is almost impossible to eradicate it.^[5] Listeria monocytogenes is commonly found in soil, stream water, sewage, plants, and food.^[6] Listeria are responsible for listeriosis, a rare but potentially lethal food-borne infection. The case fatality rate for those with a severe form of infection may approach 25%.^[7] (Salmonella, in comparison, has a mortality rate estimated at less than 1%^[8]). Although Listeria monocytogenes has low infectivity, it is hardy and can grow in temperatures from 4 °C (39.2 °F) (the temperature of a refrigerator), to 37 °C (98.6 °F), (the body's internal temperature).^[6] Listeriosis is a serious illness, and the disease may manifest as meningitis, or affect newborns due to its ability to penetrate the endothelial layer of the placenta.^[7]

Pathogenesis

Main article: Listeria monocytogenes

Listeria uses the cellular machinery to move around inside the host cell: It induces directed polymerization of actin by the ActA transmembrane protein, thus pushing the bacterial cell around.^[9]

Listeria monocytogenes, for example, encodes virulence genes that are thermoregulated. The expression of virulence factor is optimal at 37 degrees Celsius and is controlled by a transcriptional activator, PrfA, whose expression is thermoregulated by the PrfA thermoregulator UTR element. At low temperatures, the PrfA transcript is not translated due to structural elements near the ribosome binding site. As the bacteria infect the host, the temperature of the host melts the structure and allows translation initiation for the virulent genes.

The majority of Listeria bacteria are targeted by the immune system before they are able to cause infection. Those that escape the immune system's initial response, however, spread through intracellular mechanisms and are, therefore, guarded against circulating immune factors (AMI).^[7]

To invade, Listeria induces macrophage phagocytic uptake by displaying D-galactose in their teichoic acids that are then bound by the macrophage's polysaccharide receptors. Other important adhesins are the internalins.^[8] Once phagocytosed, the bacterium is encapsulated by the host cell's acidic phagolysosome organelle.^[6] Listeria, however, escapes the phagolysosome by lysing the vacuole's entire membrane with secreted hemolysin,^[10] now characterized as the exotoxin listeriolysin O.^[6] The bacteria then replicate inside the host cell's cytoplasm.^[7]

Listeria must then navigate to the cell's periphery to spread the infection to other cells. Outside the body, listeria has flagellar-driven motility, sometimes described as a "tumbling motility." However, at 37 °C, flagella cease to develop and the bacterium instead usurps the host cell's cytoskeleton to move.^[7] Listeria, inventively, polymerizes an actin tail or "comet",^[10] from actin monomers in the host's cytoplasm ^[5] with the promotion of virulence factor ActA.^[7] The comet forms in a polar manner ^[11] and aids the bacteria's migration to the host cell's outer membrane. Gelsolin, an actin filament severing protein, localizes at the tail of listeria and accelerates the bacterium's motility.^[11] Once at the cell surface, the actin-propelled listeria pushes against the cell's membrane to form protrusions called filopods^[6] or "rockets". The protrusions are guided by the cell's leading edge ^[12] to contact adjacent cells, which then engulf the listeria rocket and the process is repeated, perpetuating the infection.^[7] Once phagocytosed, the listeria is never again extracellular: it is an intracytoplasmic parasite ^[10] like Shigella flexneri and Rickettsia.^[7]

Epidemiology

The Center for Science in the Public Interest has published a list of foods that have sometimes caused outbreaks of Listeria: hot dogs, deli meats, raw milk, cheeses (particularly soft-ripened cheeses like feta, Brie, Camembert, blue-veined, or Mexican-style “queso blanco”), raw and cooked poultry, raw meats, ice cream, raw vegetables, raw and smoked fish.^[13] Cantaloupe has been implicated in an outbreak of listeriosis from a farm in Colorado,^[14] and the Australian company GMI Food Wholesalers were fined AU$236,000 for providing Listeria monocytogenes contaminated chicken wraps to the airline Virgin Blue.^[15]

Prevention

Preventing listeria as a food illness requires effective sanitation of food contact surfaces. Alcohol is an effective topical sanitizer against Listeria. Quaternary ammonium can be used in conjunction with alcohol as a food contact safe sanitizer with increased duration of the sanitizing action. Refrigerated foods in the home should be kept below 4 °C (39.2 °F) to discourage bacterial growth. Preventing listeriosis also can be done by carrying out an effective sanitation of food contact surfaces.^[16]

Treatment

Antibiotics effective against listeria species include ampicillin, vancomycin (unclear effectiveness), ciprofloxacin, linezolid, azithromycin.

Mixtures of bacteriophages have also proven effective in the treatment of Listeria.^[17]

Research

Listeria is an opportunistic pathogen: It is most prevalent in the elderly, pregnant mothers, and AIDS patients. With improved healthcare leading to a growing elderly population and extended life expectancies for AIDS patients, physicians are more likely to encounter this otherwise-rare infection (only 7 per 1,000,000 healthy people are infected with virulent listeria each year).^[6] Better understanding the cell biology of Listeria infections, including relevant virulence factors, may lead to better treatments for listeriosis and other intracytoplasmic parasite infections. Researchers are now investigating the use of listeria as a cancer vaccine, taking advantage of its "ability to induce potent innate and adaptive immunity."^[5][18]

See also

• 2008 Canadian listeriosis outbreak
• 2011 United States listeria outbreak
• List of foodborne illness outbreaks

References

1. ^ Christelle Guillet, Olivier Join-Lambert, Alban Le Monnier, Alexandre Leclercq, Frédéric Mechaï, Marie-France Mamzer-Bruneel, Magdalena K. Bielecka, Mariela Scortti, Olivier Disson, Patrick Berche, José Vazquez-Boland, Olivier Lortholary, and Marc Lecuit. Human Listeriosis Caused by Listeria ivanovii. Emerg Infect Dis. 2010 January; 16(1): 136–138.
2. ^ Elliot T. Ryser, Elmer H. Marth. Listeria, Listeriosis, and Food Safety. Second edition. Elmer Marth. 1999.
3. ^ M. D. Collins, S. Wallbanks, D. J. Lane, J. Shah, R. Nietupskin, J. Smida, M. Dorsch and E. Stackebrandt. Phylogenetic Analysis of the Genus Listeria Based on Reverse Transcriptase Sequencing of 16S rRNA. International Journal of Systematic and Evolutionary Microbiology. April 1991 vol. 41 no. 2 240-246
4. ^ http://www.guardian.co.uk/world/2011/sep/29/listeria-outbreak-us-cantaloupe-melons?newsfeed=true
5. ^ ^{a b c} {{cite web Once a food processing plant has listeria contamination, it is nearly impossible to eliminate it. (Source, Secret Agents" Secret Agents: The Menace of Emerging Infections [Hardcover] Madeline Drexler, Hardcover: 332 pages ISBN-10: 0309076382 ISBN-13: 978-0309076388. Average amazon review 5 stars. | title =Controlling Listeria Contamination in Your Meat Processing Plant | publisher =Government of Ontario | date = 27 February 2007 | url =http://www.omafra.gov.on.ca/english/food/inspection/meatinsp/controllinglisteria.htm | accessdate = 2010-04-27 }}
6. ^ ^{a b c d e f} "More About Listeria". University of Florida Medical School. http://www.med.ufl.edu/biochem/DLPURICH/morelist.html. Retrieved 2007-03-07. 
7. ^ ^{a b c d e f g h} "Todar's Online Textbook of Bacteriology". Listeria monocytogenes and Listeriosis. Kenneth Todar University of Wisconsin-Madison Department of Biology. 2003. http://textbookofbacteriology.net/Listeria.html. Retrieved 2007-03-07. 
8. ^ ^{a b} "Statistics about Salmonella food poisoning". WrongDiagnosis.com. 27 February 2007. http://www.wrongdiagnosis.com/s/salmonella_food_poisoning/stats.htm. Retrieved 2007-03-07. 
9. ^ "Trends in Microbiology". How the Listeria monocytogenes ActA protein converts actin polymerization into a motile force. Cell Press. July 1997. pp. 272-276. http://www.ncbi.nlm.nih.gov/pubmed/9234509. Retrieved 2011-09-29. 
10. ^ ^{a b c} Tinley, L.G. et al. (1989). "Actin Filaments and the Growth, Movement, and Spread of the Intracellular Bacterial Parasite, Listeria monocytogenes". The Journal of Cell Biology 109 (4 Pt 1): 1597–1608. doi:10.1083/jcb.109.4.1597. PMC 2115783. PMID 2507553. http://www.jcb.org/cgi/reprint/109/4/1597. 
11. ^ ^{a b} Laine RO, Phaneuf KL, Cunningham CC, Kwiatkowski D, Azuma T, Southwick FS (1 August 1998). "Gelsolin, a protein that caps the barbed ends and severs actin filaments, enhances the actin-based motility of Listeria monocytogenes in host cells". Infect. Immun. 66 (8): 3775–82. PMC 108414. PMID 9673261. http://iai.asm.org/cgi/pmidlookup?view=long&pmid=9673261. 
12. ^ Galbraith CG, Yamada KM, Galbraith JA (February 2007). "Polymerizing actin fibers position integrins primed to probe for adhesion sites". Science 315 (5814): 992–5. doi:10.1126/science.1137904. PMID 17303755. http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=17303755. 
13. ^ Center for Science in the Public Interest – Nutrition Action Healthletter – Food Safety Guide – Meet the Bugs
14. ^ William Neuman (September 27, 2011). "Deaths From Cantaloupe Listeria Rise". The New York Times. http://www.nytimes.com/2011/09/28/business/deaths-from-cantaloupe-listeria-rises.html?_r=1. Retrieved 13 November 2011. 
15. ^ Josephine Tovey (November 16, 2011). "$236,000 fine for foul flight chicken". The Sydney Morning Herald. http://www.smh.com.au/travel/travel-incidents/236000-fine-for-foul-flight-chicken-20111115-1nh99.html. Retrieved 13 November 2011. 
16. ^ "Maple Leaf Foods assessing Listeria-killing chemical". ctv.ca (ctvglobemedia). 2008-10-12. http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20081012/maple_leaf_foods_081012/20081012?hub=Health. Retrieved 2008-10-15. 
17. ^ [1], Micreos Food safety
18. ^ Greenemeier L (May 21, 2008). "Recruiting a Dangerous Foe to Fight Cancer and HIV"]. Scientific American. http://www.sciam.com/article.cfm?id=recruiting-a-dangerous-foe&sc=rss. 

Sources

• Abrishami, S.H., B.D. Tall, T.J. Bruursema, P.S. Epstein, and D.B. Shah. 1994. "Bacterial adherence and viability on cutting board surfaces". Journal of Food Safety. 14: 153–172.
• Allerberger, F. 2003. "Listeria: growth, phenotypic differentiation and molecular microbiology". FEMS Immunology and Medical Microbiology. 35: 183–189.
• Bayles, D.O., and B.J. Wilkinson. 2000. "Osmoprotectants and cryoprotectants for Listeria monocytogenes". Letters in Applied Microbiology. 30: 23–27.
• Bredholt, S., J. Maukonen, K. Kujanpaa, T. Alanko, U. Olofson, U. Husmark, A.M. Sjoberg, and G. Wirtanen. 1999. "Microbial methods for assessment of cleaning and disinfection of food-processing surfaces cleaned in a low-pressure system". European Food Research and Technology. 209: 145–152.
• Chae, M.S. and H. Schraft. 2000. "Comparative evaluation of adhesion and biofilm formation of different Listeria monocytogenes strains". International Journal of Food Microbiology. 62:103–111.
• Chen, Y.H., K.M. Jackson, F.P. Chea, D.W. Schaffner. 2001. "Quantification and variability analysis of bacterial cross-contamination rates in common food service tasks". Journal of Food Protection. 64: 72–80.
• Davidson, C.A., C.J. Griffith, A.C. Peters, and L.M. Fieding. 1999. "Evaluation of two methods for monitoring surface cleanliness ñ ATP bioluminescence and traditional hygiene swabbing". Luminescence. 14: 33–38.
• Food and Drug Administration (FDA). 2005. "Foodborne Pathogenic Microorganisms and Natural Toxins Handbook: The ìBad Bug Book" Food and Drug Administration, College Park, MD. Accessed: 1 March 2006.
• Foschino, R., C. Picozzi, A. Civardi, M. Bandini, and P. Faroldi. 2003. "Comparison of surface sampling methods and cleanability assessment of stainless steel surfaces subjected or not to shot peening". Journal of Food Engineering. 60:375–381.
• Frank, J.F. 2001. "Microbial attachment to food and food contact surfaces". In: Advances in Food and Nutrition Research, Vol. 43. ed. Taylor, S.L. San Diego, CA. Academic Press., Inc. 320–370.
• Gasanov, U., D. Hughes, and P.M. Hansbro. 2005. "Methods for the isolation and identification of Listeria spp. and Listeria monocytogenes: a review". FEMS Microbiology Reviews. 29: 851–875.
• Gombas, D.E., Y. Chen, R.S. Clavero, and V.N. Scott. 2003. "Survey of Listeria monocytogenes in ready-to-eat foods". Journal of Food Protection. 66: 559–569.
• Helke, D.M., E.B. Somers, and A.C.L. Wong. 1993. "Attachment of Listeria monocytogenes and Salmonella typhimurium to stainless steel and Buna-N-rubber surfaces in the presence of milk and individual milk components". Journal of Food Protection. 56: 479–484.
• Kalmokoff, M.L., J.W. Austin, X.D. Wan, G. Sanders, S. Banerjee, and J.M. Farber. 2001. "Adsorption, attachment and biofilm formation among isolates of Listeria monocytogenes using model condit ions". Journal of Applied Microbiology. 91: 725–34.
• Kusumaningrum, H.D., G. Riboldi, W.C. Hazeleger and R.R. Beumer. 2003. "Survival of foodborne pathogens on stainless steel surfaces and cross-contamination to foods". International Journal of Food Microbiology. 85: 227–236.
• Lin, C., K. Takeuchi, L. Zhang, C.B. Dohm, J.D. Meyer, P.A. Hall, and M.P. Doyle. 2006. "Cross-contamination between processing equipment and deli meats by Listeria monocytogenes". Journal of Food Protection. 69:559–569.
• Low, J.C. and W. Donachie. 1997. "A review of Listeria monocytogenes and listeriosis". The Veterinary Journal. 153: 9–29.
• MacNeill, S., D.M. Walters, A. Dey, A.G. Glaros, C.M. Cobb. 1998. "Sonic and mechanical toothbrushes". Journal of Clinical Periodontology. 25: 988–993.
• Maxcy, R.B. 1975. "Fate of bacteria exposed to washing and drying on stainless steel". Journal of Milk and Food Technology. 38(4): 192–194.
• McInnes, C., D. Engel, and R.W. Martin. 1993. "Fimbriae damage and removal of adherent bacteria after exposure to acoustic energy". Oral Microbiology and Immunology. 8: 277–282.
• McLauchlin, J. 1996. "The relationship between Listeria and listeriosis". Food Control. 7(45): 187–193.
• Montville, R., Y.H. Chen, D.W. Schaffner. 2001. "Glove barriers to bacterial cross contamination between hands to food". Journal of Food Protection. 64: 845–849.
• Moore, G., C. Griffith, and L. Fielding. 2001. "A comparison of traditional and recently developed methods for monitoring surface hygiene within the food industry: a laboratory study". Dairy, Food, and Environmental Sanitation. 21: 478–488.
• Moore, G. and C. Griffith. 2002a. "Factors influencing recovery of microorganisms from surfaces by use of traditional hygiene swabbing". Dairy, Food, and Environmental Sanitation. 22: 410–421.
• Parini, M.R., W.G. Pitt. 2005. "Removal of oral biofilms by bubbles". Journal of American Dental Association. 136:1688–1693.
• Rocourt, J. 1996. "Risk factors for listeriosis". Food Control. 7(4/5): 195–202.
• Salo, S., A. Laine, T. Alanko, A.M. Sjoberg, and G. Wirtanen. 2000. "Validation of the microbiological methods Hygicult dipsilde, contact plate, and swabbing in surface hygiene control: a Nordic collaborative study". Journal of AOAC International. 83: 1357–1365.
• Schlech, W.F. 1996. "Overview of listeriosis". Food Control. 7(4/5): 183–186.
• Seymour, I.J., D. Burfoot, R.L. Smith, L.A. Cox, and A. Lockwood. 2002. "Ultrasound decontamination of minimally processed fruits and vegetables". International Journal of Food Science and Technology. 37: 547–557.
• Stanford, C.M., R. Srikantha, and C.D. Wu. 1997. "Efficacy of the Sonicare toothbrush fluid dynamic action on removal of supragingival plaque". Journal of Clinical Dentistry. 8(1): 10–14.
• USDA-FSIS. (United States Department of Agriculture – Food Safety and Inspection Service) 2003. "FSIS Rule Designed To Reduce Listeria monocytogenes In Ready-To-Eat Meat And Poultry Products". United States Department of Agriculture Food Safety and Inspection Service, Washington, DC. Accessed: 1 March 2006
• Vorst, K.L., E.C.D. Todd, and E.T. Ryser. 2004. "Improved quantitative recovery of Listeria monocytogenes from stainless steel surfaces using a one-ply composite tissue". Journal of Food Protection. 67(10): 2212–2217. * Whyte, W., W. Carson and A. Hambraeus. 1989. "Methods for calculating the efficiency of bacterial surface sampling techniques". Journal of Hospital Infection. 13: 33–41.
• Wu-Yuan, C.D. and R.D. Anderson. 1994. "Ability of the SonicareÆ electronic toothbrush to generate dynamic fluid activity that removes bacteria". The Journal of Clinical Dentistry. 5(3): 89–93.
• Zhao, P., T. Zhao, M.P. Doyle, J.R. Rubino, J. Meng. 1998. "Development of a model for evaluation of microbial cross-contamination in the kitchen". Journal of Food Protection. 61: 960–963.
• Zottola, E.A., and K.C. Sasahara. 1994. "Microbial biofilms in the food processing industry ñ should they be a concern?" International Journal of Food Microbiology. 23: 125–148.

External links

• Listeriosis at the Open Directory Project
• Listeria genome at PATRIC, funded by the National Institute of Allergy and Infectious Diseases