VM2G9 - EHEC O157:H7 by Luo Zaini https://padlet.com/luozaini/VM2Team9 The Pathogenic Bacteria ! en-us 2017-03-28 07:22:40 UTC 2025-10-03 04:05:38 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Rafaelo.png Introduction luozaini https://padlet.com/luozaini/VM2Team9/wish/163028122 The bacteria that we choose is Enterohaemorrhagic Escherichia coli (EHEC) or known as
E. coliO157:H7, it is a major food borne pathogen causing severe disease in humans.

So why it is known as O157:H7? The O (oh) stands for sOmatic antigens that located on the
body of bacteria and O157 means that this was the 157th different kind of O antigen
found in E. coli. H antigens are the antigens that located on the tail or flagella, H7 means
that this was the 7th different kind of H antigen found in E. coli. 

During an investigation on an outbreak of bloody diarrhoea in Oregon and Michigan, U.S.A in 1982, this EHEC serotype O157:H7 was first recognized. 
 ]]> 2017-03-28 07:26:10 UTC https://padlet.com/luozaini/VM2Team9/wish/163028122 Basic Biochemistry Characteristics to Identify EHEC O157:H7 luozaini https://padlet.com/luozaini/VM2Team9/wish/163030634 The basic biochemistry characteristics of E. coli are lactose fermenters, catalase positive, oxidase negative, methyl red positive, Voges-Proskauer negative, Indole positive, citrate negative, urease negative, positive nitrate reduction, produce acid from lactose fermentation and gas production, no Hydrogen sulphite H2S production.

However, EHEC O157:H7 have two distinct properties which may be used both in the isolation and differentiation of the strains. Firstly, E. coli O157:H7 shows slow Dsorbitol fermentation, with capacity within 48 hours. Secondly, it has inability of
producing β-glucuronidase, which can hydrolyse 4-methyl-umbelliferyl-Dglucuronide (MUG), which is a synthetic molecule. 
 ]]> 2017-03-28 07:38:13 UTC https://padlet.com/luozaini/VM2Team9/wish/163030634 EHEC ??? luozaini https://padlet.com/luozaini/VM2Team9/wish/163033068 2017-03-28 07:48:38 UTC https://padlet.com/luozaini/VM2Team9/wish/163033068 Biochemistry Characteristics : Differentiation of Escherichia from other species of Escherichia. luozaini https://padlet.com/luozaini/VM2Team9/wish/163033533 (Source: Varnam, A. H. & Evans, M. G. (1996). Foodborne Pathogens An Illustrated Text. London, UK:
Manson Publishing Ltd.) ]]> 2017-03-28 07:50:45 UTC https://padlet.com/luozaini/VM2Team9/wish/163033533 Biochemistry Characteristics : Differentiation of E. coli from other species of Escherichia. luozaini https://padlet.com/luozaini/VM2Team9/wish/163034026 (Source: Varnam, A. H. & Evans, M. G. (1996). Foodborne Pathogens An Illustrated Text. London, UK:
Manson Publishing Ltd.) 
 ]]> 2017-03-28 07:53:00 UTC https://padlet.com/luozaini/VM2Team9/wish/163034026 wawa149 https://padlet.com/luozaini/VM2Team9/wish/163052101 Distribution of topic]]> 2017-03-28 09:16:43 UTC https://padlet.com/luozaini/VM2Team9/wish/163052101 where is the organism found ? azeejohari https://padlet.com/luozaini/VM2Team9/wish/163149619 2017-03-28 14:43:24 UTC https://padlet.com/luozaini/VM2Team9/wish/163149619 food items associated with E.coli happygurlzareness https://padlet.com/luozaini/VM2Team9/wish/164383823
Mostly E.coli associated with raw materials such as raw fruits and vegetables, untreated water ,unpasteurized milk and raw milk product. There was also cases involved unpasteurized apple juice or cider (Joe Whitworth, 2017).

Most common food associated with E.coli are undercooked ground beef and also unpasteurized cow and goat milk(WA Ferens , 2011).

From other resources, there are also undercooked meat and sausages (roast pork, salami and venison). Nuts and pickled vegetables and also seafood meat are not exception . Suprisingly, E.coli also can associated with raw prepackaged cookie dough and rice cakes (www.cfsph.iastate.edu , 2016)

]]> 2017-04-03 15:50:00 UTC https://padlet.com/luozaini/VM2Team9/wish/164383823 food items happygurlzareness https://padlet.com/luozaini/VM2Team9/wish/164400432 raw fruits and vegetables]]> 2017-04-03 16:35:56 UTC https://padlet.com/luozaini/VM2Team9/wish/164400432 undercooked meat happygurlzareness https://padlet.com/luozaini/VM2Team9/wish/164400736 salami]]> 2017-04-03 16:36:51 UTC https://padlet.com/luozaini/VM2Team9/wish/164400736 food item happygurlzareness https://padlet.com/luozaini/VM2Team9/wish/164401165 rice cakes]]> 2017-04-03 16:38:15 UTC https://padlet.com/luozaini/VM2Team9/wish/164401165 Characteristic asyaz_238 https://padlet.com/luozaini/VM2Team9/wish/165513212 E. coli is a Gram-negative rod bacterium. It is facultative anaerobe and motile which has peritrichous flagella. E.coli, which is mostly harmless, found in the GI tract of mammals and also inhibit healthy human intestine. (Gally, DL, Stevens, MP (2017))

E. coli O157:H7 was first reported in 1982 by the CDC. It is one of several pathotypes (cause diarrhea) that is classified as enterohemorrhagic E. coli (EHEC) and cause diseases by producing toxin; Shiga toxin. This type of toxin can cause bloody diarrhea and approximately 5-10% of the cases are hemolytic uremic syndrome (HUS).

It is estimated that only about 100 cells of this bacteria can cause infection.  It is about 2-50% of the attack rate of persons exposed to E. coli 0157:H7 which has caused 36% of an estimated 265,000 Shiga toxin infections in the United States annually. (Nguyen, Y., & Sperandio, V. (2012). Enterohemorrhagic E. coli (EHEC) pathogenesis.)


]]> 2017-04-08 15:54:50 UTC https://padlet.com/luozaini/VM2Team9/wish/165513212 Taxonomy asyaz_238 https://padlet.com/luozaini/VM2Team9/wish/165513252 Domain = Bacteria 

Phylum = Proteobacteria 

Class = Gammaproteobacteria 

Order = Enterobacteriales 

 Family = Enterobacteriaceae 

Genus = Escherichia

species = E. coli

subspecies = O157:H7

prototype strain = EDL933

]]> 2017-04-08 15:55:46 UTC https://padlet.com/luozaini/VM2Team9/wish/165513252 Detection and Identification Method fatinizzaty915 https://padlet.com/luozaini/VM2Team9/wish/165542019 * Culture plating media
The inability of most E. coli O157 to ferment sorbitol is exploited in sorbitol McConkey agar (SMAC). Cefixime and potassium tellurite may be added to the SMAC (CT-SMAC) to increase selectivity in heavily contaminated samples. E. coli O157 generally produces colourless colonies when cultured on this media, thus distinguishing it from other VTEC serogroups and other micro-flora. This is the media of choice in the ISO standard protocol (ISO 16654) for E. coli 0157.]]> 2017-04-09 09:31:59 UTC https://padlet.com/luozaini/VM2Team9/wish/165542019 Detection and Identification method fatinizzaty915 https://padlet.com/luozaini/VM2Team9/wish/165542810 There are several methods of detection and identification of EHEC 0157 such as
1. Culture plating media
2. immunological method
3. Serodiagnosis]]> 2017-04-09 09:54:28 UTC https://padlet.com/luozaini/VM2Team9/wish/165542810 Other agars that have been optimised for the identification of specific VTEC serogroups and are listed in Table 2. fatinizzaty915 https://padlet.com/luozaini/VM2Team9/wish/165543509 Enterohaemorrhagic E. coli (EHEC) are a subset of   VTEC.]]> 2017-04-09 10:11:33 UTC https://padlet.com/luozaini/VM2Team9/wish/165543509 Outbreaks caused by EHEC mienawani96 https://padlet.com/luozaini/VM2Team9/wish/165552363
Enterohemorrhagic Escherichia coli (EHEC) is a subset of pathogenic E. coli that
can cause diarrhea or hemorrhagic colitis in humans
1)German, 2011- Bloody diarrhea and haemolytic ureamic syndrome by shiga toxins-producing E.coli via contiminated raw food  (R Burger 2012)
2)Japan,2010-2013- childcare faciities due to lack of hygiene (A Kanayama et.all,2015)
3) United States, 1982-2002-Epidemiology of Escherichia coli due to various contamination (infected from other person, contaminated food vehicle, contaminated water, raw food) (JM Rangel et.all, 2005)]]> 2017-04-09 13:55:10 UTC https://padlet.com/luozaini/VM2Team9/wish/165552363 Importance from public health point of view nshirah96 https://padlet.com/luozaini/VM2Team9/wish/165555998 1. Contaminate foods
- pose a significant threat to human health in kinds of foods that are the most likely to disseminate EHEC and to be consumed raw or undercooked.
- may cause food-borne infections leading to life-threatening diseases in humans.
- 75% of EHEC outbreaks are linked to the consumption of contaminated bovine- derived products.
- can grow in acidic foods, down to a pH of 4.4, and in foods with a minimum water activity (aW) of 0.95. 
- any food source that is subject to fecal contamination can serve as a vehicle.
- it is transmitted to humans primarily through consumption of contaminated foods, such as raw or undercooked ground meat products and raw milk, as well as cross-contamination during food preparation.

 

]]> 2017-04-09 15:04:35 UTC https://padlet.com/luozaini/VM2Team9/wish/165555998 Cause outbreaks of bloody diarrhea and hemolytic uremic syndrome (HUS) worldwide. hafizah9613amdan https://padlet.com/luozaini/VM2Team9/wish/166411034
http://www.who.int/mediacentre/factsheets/fs125/en/]]> 2017-04-14 23:53:52 UTC https://padlet.com/luozaini/VM2Team9/wish/166411034 Appropriate interventions to prevent growth of EHEC O157:H7 minsyuhada https://padlet.com/luozaini/VM2Team9/wish/166414723 Sanitation method
1. SEPARATE
-Keep all ready to eat (RTE) foods, raw meat, poultry, and seafood separate from items that traditionally do not get cooked or potentially can be eaten raw.
-Use separate utensils for raw and cooked foods.
-Store meats and other potential sources of contamination in areas below foods that may be consumed raw.
-Rewrap open packages carefully or store in leak proof containers.

2. CLEAN
-Use hot, soapy water and a sanitizer to wash hands and surfaces that contact food often.
-Sanitize all utensils, cutting boards, and work surfaces before and after use, using an approved sanitizing agent made for use on food or food contact surfaces.
-Wash all vegetables and fruits thoroughly before consumption.

3. COOK
-Always heat foods to safe temperatures.
-Heat food to an internal temperature of 145F (63OC) or
above for 15 seconds for most potentially hazardous foods.
-Do not store food in the temperature danger zone between 41F (5OC) and 135F (57OC).
-The refrigerator should be at 41F (5OC) or colder. All food should be refrigerated promptly.
-Completely cook or boil foods to 160F (71OC) and poultry products to 165F (74OC) or above.]]> 2017-04-15 02:55:29 UTC https://padlet.com/luozaini/VM2Team9/wish/166414723 minsyuhada https://padlet.com/luozaini/VM2Team9/wish/166415297 2017-04-15 03:30:16 UTC https://padlet.com/luozaini/VM2Team9/wish/166415297 Step to wash your hand minsyuhada https://padlet.com/luozaini/VM2Team9/wish/166415471 2017-04-15 03:41:05 UTC https://padlet.com/luozaini/VM2Team9/wish/166415471 Favorable growth condition wawa149 https://padlet.com/luozaini/VM2Team9/wish/166525134 - Bacteria need some basic living conditions to grow in, and raw meats provide close too ideal growth conditions at room temperatures. Under these conditions E. Coli, if present in even small, possibly undetectable quantities, will double every hour and ten minutes.
- E coli 0157: H7 can grow on refrigerated packed vegetables, as has been reported for Listeriamonocytogenes (Berrang et aL 1989, Beuchat and Bracket 1990, Monge and Arias 1997), Salmonella (Rosas et al. 1984) and Aeromonas hydrophila (Berrant et al. 1989)]]> 2017-04-17 11:30:14 UTC https://padlet.com/luozaini/VM2Team9/wish/166525134 Growth rate of E.coli wawa149 https://padlet.com/luozaini/VM2Team9/wish/166525714 - E.coli can be considered as mesophiles microorganism. that can grow at range 15-45 Degree celcius.
- but it grow faster at 37 degre]]> 2017-04-17 11:38:26 UTC https://padlet.com/luozaini/VM2Team9/wish/166525714 favourable growth condition tenmilo88 https://padlet.com/luozaini/VM2Team9/wish/167198594 TEMPERATURE
~optimal conditions to growth is approximately 8–10C (Buchanan and Bagi, 1994; Rajkowski and Marmer, 1995)
pH
~Growth rates are similar at pH values between 5.5 and 7.5, but decline rapidly at lower pH values (Buchanan and Klawitter, 1992).]]> 2017-04-20 08:20:53 UTC https://padlet.com/luozaini/VM2Team9/wish/167198594