Microbiology help

Hey junior271,

Epidemiology is the study of how often diseases occur in different groups of people and why.

Transmission means how it moves from person to person or how a person contracts the illness.

Pathogenicity means the ability of the microorganism to invade the host and produce a disease. It is a qualitative
description of a species of bacteria. Microbes express their pathogenicity by means of their virulence, a term which refers to the degree of pathogenicity of the microbe.

The good news is that I've written about these pathogens in the past:

- http://www.ppdictionary.com/bacteria/gnbac/jejuni.htm
- http://www.ppdictionary.com/bacteria/gnbac/typhimurium.htm

For instance, salmonella is transmitted by fecal oral spread. The bacteria is shed in the feces (stools) of people and animals infected with salmonella. You get salmonella by eating food or drinking beverages that have been contaminated with feces from infected people or animals. You can also get it if you contaminate your own hands cleaning up animal droppings or handling raw poultry and meat then eating with your hands or putting your hands in your mouth. The bacteria may be easily spread within the family unit and between small children. Once food has been contaminated, the bacteria can live on it and if the contaminated item is not refrigerated the bacteria will multiple increasing the risk of illness.

- The ability of a microorganism to cause disease is called pathogenicity, and the degree of pathogenicity is called virulence. Pathogens have a variety of traits that enable them to cause disease; collectively, these are called virulence factors.

- Epidemiology is the study of the location, course, and transmission of diseases within populations.

Campylobacter jejuni

Campylobacter jejuni is a comma-shaped, Gram-negative, oxidase-positive organism with polar flagella in the class Deltaproteobacteria. It is likely the most common cause of bacterial gastroenteritis in the United States, with an estimated 2
million cases a year. The pathogen occurs in many domesticated animals, particularly poultry. Humans become infected by ingesting food, milk, or water contaminated with infected animal feces. The infection, which is self-limiting, causes
malaise, fever, abdominal pain, and frequent, bloody diarrhea and may last 7–10 days. Proper food handling and cooking food sufficiently can reduce infections.

Salmonella typhimurium

Most infections with salmonellae result from the consumption of food contaminated with animal feces. The pathogen is also common in foods containing poultry or eggs. Infections with fewer than 1 million cells of most strains are
usually asymptomatic in people with healthy immune systems. Larger infective doses result in salmonellosis, which is characterized by nonbloody diarrhea, nausea, and vomiting. Humans are the sole hosts of Salmonella typhi, which
causes typhoid fever, a condition marked by fever, headache, and malaise. Carriers of S. typhi are often asymptomatic, but physicians may remove the gallbladder of a carrier so that the person does not infect others.

Hope this information helped!

Duddz

Hi,

Thank you for the replies i appreciate your help.

I have almost finished the question with your help but i am still confused on something. The question asks me to compare and contrast, would the following be comparing and contrasting? If someone can give me an example of a good way to compare and contrast i would be gratefull.

Studies have shown C.Jejuni is transmitted through consumption of contaminated water, contact with domestic or wild animals or contaminated food such as ground beef that originates from carcasses that are contaminated at slaughter. Unsafe food handling and storing food at incorrect temperatures contributes to the transmission. In addition, the incomplete cooking of food and person to person sexual contact contributes to the transmission.  C. jejuni reservoirs include wild birds, poultry, cattle, sheep, cat, dogs, raw milk, and contaminated water. 

In contrast Salmonella food poisoning results from consumption of contaminated food such as raw or undercooked eggs, milk, meat, water or hands. People may become infected if they transfer animal faeces infected with salmonella  from their hands to their mouths, for example if a person handles animal droppings and then eats without washing the hands. Person to person spread can occur when hands, objects or food become contaminated with faeces from people who are infected.

Hi

Another thing, isnt incidence and epidemiology the same thing?

Essentially, yes. Epidemology incorportates incidence (a.k.a occurrence), prevalence, etc.

Incidence is a measure of the risk of developing some new condition within a specified period of time.

Hi,

Thank you for the replies i appreciate your help.

 The question asks me to compare and contrast, would the following be comparing and contrasting? If someone can give me an example of a good way to compare and contrast i would be gratefull.

Studies have shown C.Jejuni is transmitted through consumption of contaminated water, contact with domestic or wild animals or contaminated food such as ground beef that originates from carcasses that are contaminated at slaughter. Unsafe food handling and storing food at incorrect temperatures contributes to the transmission. In addition, the incomplete cooking of food and person to person sexual contact contributes to the transmission.  C. jejuni reservoirs include wild birds, poultry, cattle, sheep, cat, dogs, raw milk, and contaminated water.

In contrast Salmonella food poisoning results from consumption of contaminated food such as raw or undercooked eggs, milk, meat, water or hands. People may become infected if they transfer animal faeces infected with salmonella  from their hands to their mouths, for example if a person handles animal droppings and then eats without washing the hands. Person to person spread can occur when hands, objects or food become contaminated with faeces from people who are infected.

When you compare and contrast, you have to use words like "similarly", "whereas", "however", "in contrast", "rather", etc.

It should be written like this: (Note: this is a rough draft)...

Both Salmonella species and C. Jejuni are transmitted through the consumption of contaminated food items. Whereas C. Jejuni is spread via water, contact with domestic or wild animals, or contaminated food such as ground beef,  Salmonella food poisoning solely results from the consumption of raw or undercooked eggs, milk, and meat, or to a lesser extent, contaminated water. Similarly, unsafe food handling and storing food at incorrect temperatures contributes to the transmission of both pathogens. In terms of Salmonella species, some people become infected if they transfer animal faeces infected with salmonella  from their hands to their mouths. For instance, if a person handles animal droppings and then eats without washing the hands. Person to person spread can occur when hands, objects or food become contaminated with faeces from people who are infected.

Hi,

Thank you for replying back, i appreciate your help. I am ok with the compare and contrast question and i have managed to get it complete. I have another question below that i do need help with, i am having trouble how to structure the answer by discussing the similarities and distinguishing features.

"Discuss the similarities and distinguishing features of the nature of food borne disease caused by VTEC and Listeria monocytogenes in the UK"

Using the compare and contrast example you gave above how would you structure that to discuss the similarities and distinguinshing features?

I just need to know how to structure paragraphs and what words to use.

Okay, so you want to compare and contrast based on the incidence, epidemiology, transmission and pathogenicity of these organisms? If so, start your paragraph by introducing the epidemiology of one of the pathogens, start with L. monocytogenes. Then move on to transmission, pathogenicity, etc.

Use the following two websites:

L. monocytogenes: http://www.ppdictionary.com/bacteria/gpbac/listeria.htm
Verocytotoxin-producing Escherichia coli: http://www.amm.co.uk/files/factsabout/fa_vtec.htm

Wherever you see a similarity, use the terms similarly or:

"Much the same", "which is comparable", "this is analogous to", "likewise", "in the same way".

Wherever there is a contrast, use:

"However, ...", "unlike E. coli, L. monocytogenes has a ...", "On the other hand,  L. monocytogenes has the capability to withstand temperatures ..."

Write your first paragraph and post it here...

GL

Hi,

I think i may have confused you a little i apologise for the confusing info. In my very first post and the question you have been helping me with was a compare and contrast question which you will find below, i am ok with this question and do not need any more help.

"Campylobacter and Salmonellae are the most common causes of bacterial gastroenteritis. Compare and contrast the incidence, epidemiology,
transmission and pathogenicity of these organisms.

In my last post i posted another question that i am trying complete which you will find below, now the question is asking me to discuss the similarities and distinguishing features, now how would i create a paragraph which would be discussing the similarities and distinguising features? and what do you think it means by the nature of food borne disease should i focus on the diseases both cause such as listerosis and HUS?

"Discuss the similarities and distinguishing features of the nature of food borne disease caused by VTEC and Listeria monocytogenes in the UK"


Also would it be possible to email you privately? i will complete the answer for the question and i would appreciate if you could take a look at it, im just a little catious as i do not want anyone using my answer as their own.

Sorry junior272, I'm somewhat busy when it comes to editing people's work. However, I will try to explain this to you as best as I can. Similarities and distinguising features means the exact same thing as before, that is, what features are similar and what features are different of the diseases caused by these food borne pathogens. For instance, both pathogens infect the intestines (the primary site of infection). Said differently, those infected with listeriosis often experience ... so and so ... and those infected with Verocytotoxin-producing Escherichia coli get bloody diarrhoea. But whereas L. monocytogenes can cross the placenta and cause spontaneous abortion and stillbirth, illnesses causes VTEC is only limited to infecting the gastrointestinal tract. (Recall: Listeria monocytogenes causes meningitis in newborns, the immunosuppressed, pregnant women, and cancer patients.) The nature of the disease (listeriosis) is to cross the placenta and attach fetal tissues. When septicemia (bacteria in blood infection) occurs as a result of listeria, not VTEC, mortality may reach 50%. Diseases caused by VTEC cannot cause septicemia as it mainly infects epithelial cells of the gastrointestinal tract. It does this by producing vero toxins that cause inflammation and bleeding of the colon, including hemorrhagic colitis and hemolytic uremic syndrome. L. monocytogenes cannot produce vero toxin, but rather a haemolysin called listeriolysin O. This is how it escapes being phagocytosized by immune system cells.

Hi,

I appreciate your help, i know i am asking a lot by asking you to have a look at my work, but i am in my final year at university over in the UK, and this is very important to me, i need all help i can get, university is not open agian until the new year but i have to get this done.

I basically have  a seen examination to do so i have to prepare that answers memorize and understand what ever i can and then go into an exam room for 3 hours. If you can make an exception just this once i would be gratefull?

The best I can do is reread a paragraph posted on here at most.