Isolation and Identification of Listeria Species

Isolation and Identification of Listeria Species Alesha Coleman-McCallum Title: Isolation and Identification of Listeria species from chicken sample using Palcam broth (pre-enrichment), UVM 11 broth (selective enrichment), Palcam and Oxford agars (selective plating) also confirmation using biochemical tests. Objectives: To isolate Listeria species from chicken sample To observe the reaction of listeria on selective medium To confirm the Listeria species using biochemical tests Introduction Listeria is a genus of aerobic parasitic, gram positive rod-shaped bacterium (Define, n.d). This genus has more than 10 species with the commonly encountered being: Listeria monocytogenes, Listeria innocua, Listeria ivanovii, Listeria welshimeri, Listeria seeligeri, Listeria grayi, Listeria murrayi. Members of this genus are extensively spread in the environment and maybe found in soil, plants, gastrointestinal tract of animal and humans. Listeria monocytogenes species is of great concern because it is pathogenic to humans and causes Listeriosis. Listeriosis is a foodborne illness (Hardy Diagnostics, 1996). Listeria monocytogenes is different from most bacteria since it can grow in the cold, salt, acid and air-tight conditions. The increased demand of ready to eat foods especially in first world countries has the potential of listeriosis more eminent. Pregnant women, older adults, young children and immunocompromised persons are more susceptible to Listeriosis infections. Therefore cooking, pasteurization/applying heating steps to food, avoiding raw meat and milk/ moist or processed food and washing hands regularly may reduce the risk of infections. (FDA, 2004). According to Food Quality Safety USA [4] a dry and clean work environment is crucial in avoiding listeria outbreaks in the food industry. Methods for Identification Methods used in BI208 lab for identification of Listeria were Palcam broth (pre-enrichment) then UVM 11 broth for selective enrichment step, Palcam (selective agent) and Oxford agars (selective and differential agent). For confirmation of species: organism was plated on a blood agar to check for hemolysis. Biochemical test included SIM tube for motility, mannitol, D Xylose and L Rhamnose reactions obtained. Other methods that could be used to identify listeria species are: Polymerase Chain Reaction (PCR), Rapid Identification Kits and Serological tests (MFHPB-07, 2012). Results Table showing results obtained from Listeria media reaction Media Observations Reaction Palcam Agar Shiny, smooth, circular, convex colonies. No fermentation No Hydrolsis Oxford Agar Black colour around colonies Esculin Reduction Blood Cream, hilly,glistening colonies No Beta-hemolysis Mannitol Transparent colonies Negative D Xylose Transparent colonies Negative L Rhamnose Light yellow fermentation around colonies Positive SIM Tube Umbrella shaped growth Positive Gram Stain gram positive rods Assuming Listeria monocytogenes control was used: Media Expected Results Palcam Broth Cloudy UVM 11 Cloudy Palcam Agar No fermentation Positive Hydrolysis Oxford Agar Esculin Reduction Blood Beta-hemolysis Mannitol Negative D Xylose Negative L Rhamnose Positive SIM Tube Positive Discussion Listeria innocua was isolated from the chicken sample. Listeria innocua is not usually implicated in food born-illnesses however an isolated death in an elderly patient was reported (Perrin, Bemer and Delamare, 2003). Portions of chicken sample were first placed in pre-enrichment broth in order for stressed cells to become viable and all other bacterial cells to multiply.   Enrichment stage is to partially suppress unwanted organisms and allow listeria to thrive. Oxford agar (OXA) is both selective and differential. The selective properties of OXA agar will not allow gram negative organisms to grow while suppressing most gram positive organisms (Oxoid, n.d). The different property of OXA agar will allow some species of Listeria to be totally inhibited, growth with or without blackened colonies (MFHPB-07, 2012). Palcam agar   utilizes two indicator systems: esculin and mannitol.   Listeria monocytogenes changes esculin to a black complex around colonies but does not ferment mannitol. Therefore some gram positive organisms such as enterococci and staphylococci will ferment mannitol hence can be ruled out as contaminants (Oxoid, n.d). Blood agar was used to determine if the organ ism is beta-hemolytic. Other Biochemical tests were mannitol, D Xylose, L Rhamnose and SIM Tube to differentiate and confirm the species. Since Listeria monocytogenes is pathogenic to humans a 2 Class Sampling Plan would be used to asses if the chicken is fit for consumption. Different species of an organism may exhibit variable characteristics and maybe mistaken. Listeria species were found and should be deemed unacceptable for consumption. Further testing such as PCR which is very specific could be used to conclusively identify the species present. Conclusions Based on the objectives previously outlined, isolation and Identification of Listeria species from chicken sample using Palcam broth method was very effective. References Define,n.d. Listeria Genus. Retrieved February 22, 2017 from http://www.dictionary.com/browse/listeria Hardy Diagnostics, 1996. Food Borne-illneses Retrieved February 22, 2017 from https://catalog.hardydiagnostics.com/cp_prod/Content/hugo/Listeria.htm FDA, 2004. Food-Borne Pathogenic Microorganisms and Natural Toxins Handbook: The Bad Bug Book U.S. FDA/CFSAN. Center for Food Safety and Applied Nutrition, Food and Drug Administration, College park, MD. Food Quality Safety (formerly Food Quality),2007.   Retrieved February 20, 2017 from http://www.foodqualityandsafety.com/article/prevent-and-control-listeria Jay, J.M.,Loessner, M.J. Golden, D. A. (2005). Modern Food Microbiology: Indicator of Food Microbial Quality and Safety, 476-477. United States of America: Springer Science+Business Media LLC . MFHPB-07 Method, November, 2012. The isolation of Listeria monocytogenes and other listeria species from food and environment samples using Palcam broth. Retrieved February 20, 2017 from  http://www.hc-sc.gc.ca/fn-an/res-rech/analy-meth/microbio/volume2-eng.php Monique Perrin, Michel Bemer and Catherine Delamare, 2003. Fatal Case of Listeria innocua Bacteremia: Journal of Clinical Microbiology Oxoid, n.d. Enrichment Media for Listeria. Retrieved February 20, 2017 from  http://www.oxoid.com/uk/blue/prod_detail/prod_detail.asp?pr=CM0856org=91c=uklang=EN US Government, n.d. Retrieved February 20, 2017 from https://www.foodsafety.gov/poisoning/causes/bacteriaviruses/listeria/ Zimbro, M.J., Power D.A., Miller,M.M., Wilson, G.E., Johnson, J.A., (Revised 2009). Difco BBL Manual: Palcam and Oxford Agar, Culture Media for Specific Groups of Microorganisms. United States of America: Becton, Dickinson and Company.

The first Olympic Games

The year is 776BC, and in Athens the first Olympic Games are about to start, the festivities have begun with a feast and sacrifices for the gods. The Olympic Spirit was a key part of their society. It was the one-time cultures from all of Greece could come together and celebrate, compete and enjoy. In the past few weeks we have been discussing the pros and cons of different issues and today it's the tur of Olympics. Approximately 2000 years later, what has changed, not much? But this Olympic spirit is ingrained within the Games, the international community spirit along with the best athletes coming together and competing in one of the most prestigious sporting competition in the world. I'd like to give you three reasons to explain why and Why the games will benefit Britain Firstly because of urban regeneration; this has been put at the heart of the London bid, and is a massive benefit to hosting the Olympic Games; there is the opportunity to redevelop areas that are dilapidated and have physical disorders. Although many locations in and around London will be used for Olympic Games the core location for most of the events will be the 500-acre Olympic Park in the Lower Lea Valley in East London, Which stretches over 5 boroughs: namely Tower Hamlets, Hackney, Camden, Greenwich and Stratford. 3 years ago Lower Lea Valley, was literally a dump site, with muggings at an all time high, knife crimes were going up and up. And you know why? Because no one cared about the place, it was considered to be a dirty, dangerous and dilapidated. And know gentlemen, due to the Olympic Committee's regeneration programme, the streets are clean, the alleys are well light The most important venue of the 2012 has been described as an architect's dream. Planned and already in building the 500 acre park promises an excellent site for sporting activities, with over 9 competition events, and is claimed to be the biggest sports site in Europe for nearly 150 years. Outside of the new Olympic Park, which will principally host indoor sports and track and athletic events, all of England will join in as hosts. However it is not just London that is going to benefit. Throughout the countries there will be facilities available. Already the Olympic Committee, has set up brilliant badminton centers in Birmingham, superb swimming pools in Swansea and even mountain biking in Manchester! However to gain the most from the Olympics we need to maximize the legacy effect. Currently the plan is to sell the Olympic stadium to West Ham Football Club, so that they can keep the sporting spirit alive. The legacy effect is in essence the only thing that will keep allow us to maintain the investment of hosting the Olympic Games. Britain, has the highest number of sports fans in the world, we have a pride in our sport, when we hear our national anthem at any event our hearts swell with pride. Recently in the last Commonwealth Games over a thousand British supporters flew out to India to support Team GB. We are proud to be British, Londoner, but the 2012 Olympics is not just about London. It's about team GB, it's about national pride, it's about an amazing, historical event taking place on our doorstep, it's about getting excited and involved, and it's about making sure that we maximise the legacy and the investment. As Lord Coe said â€Å"The Games will inspire the nation and give us the ability to showcase all that is great about Britain.†

The Curent Understanding of the Neurobiology of Memory...

This essay is focusing on the current understanding of the neurobiology of memory reconsolidation and its implications for psychology. This paper will specifically focus on the molecular mechanisms of reconsolidation and research relating to fear memories and using propranolol and D-cycloserine as a treatment of post-traumatic stress disorder. Memory consolidation is the process by which memories are stabilised after being acquired. Consolidation studies have traditionally focused on the hippocampus and systems consolidation, where short term memories become long term memories and independent of the hippocampus over time (Pinel, 2011). The more recently discovered process of consolidation is synaptic consolidation, where memory is encoded within hours, and requires protein synthesis and gene transcription (Pinel, 2011). Long term memories were once considered to be stable, but within the last decade, the discovery of reconsolidation, the process in which stored memories can be retri eved and held in labile short-term memory, has changed theory and research on memory (Pinel, 2011). The potential ability to modify established emotional memories through the processes of reconsolidation has important implications for the treatment of many mental disorders, including anxiety disorders, such as post-traumatic stress disorder. The neurobiological process of synaptic memory consolidation is thought to be long-term potentiation (LTP), which is the prolonged strengthening of the

Nuclear Weapons And Its Effects On The United States

Nuclear weapons have provided states with the firepower to deter attacks since the United States developed the first bombs in the 1940’s. Nation-states with the abilities to develop such weapons have solidified themselves atop the global hierarchy. Since few states have such weapons, it is naturally attention grabbing when a nation is revealed to be in the process of developing them. Iran began a nuclear program in the 1950’s with the help of the United States, who subsequently suspended aid after the Iranian Revolution in 1979 (Breachy and Sinha 1-3). After the monarchy was overthrown and replaced with a clerical Islamic government, many nations, especially the United States, began to fear that Iranians were using their nuclear program to create weapons of mass destruction (10-13). Over the years, sanctions from the United States, the European Union, and other central powers have crippled Iran’s economy. 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