Etiket Arşivleri: Bacteria

Campylobacter Jejuni ( Kim Mihalek )

What Is Campylobacter jejuni?

Bacteria

Slender, Rod Shaped*

Flagellate

Motile

Gram negative

Microaerophilic

Thermophilic

What is known about the Genome of C. jejuni?

First published 2/10/2000 in Nature by Parkhill, et al.

Unusual points

Almost complete lack of repetitive DNA sequences.

No functional inserted sequences or phage-related sequences.

Little organization of genes into operons or clusters.

Broad set of regulatory systems to adapt to varying environmental conditions

What is Campylobacteriosis?

Infectious disease caused by bacteria of genus Campylobacter.

99% C. jejuni, 1% other.

Affects the small intestine.

Not recognized as cause of human food borne illness prior to 1975.

Most common bacterial cause of diarrheal illness in the United States -More cases than Shigella and Salmonella combined.

How Prevalent Is This Disease In the United States?

Most common cause of food borne illness in the United States.

15 cases diagnosed/100,000 people annually.

Approximately 100 people die each year..

Most cases go unreported or undiagnosed

Estimated 1-4 million cases in U.S. yearly.

How Prevalent Is This Disease Worldwide?

Leading cause of food borne illness worldwide.

Many countries do not have national survey programs for Campylobacteriosis; worldwide incidence numbers do not exist.

Prevalent in developing countries.

Study by University of Lagos, Nigeria showedthat in developing countries, 40-60% of children under 5 with diarrhea were positive for Campylobacter spp.

Worldwide, gastroenteritis is second only to respiratory infections in causing deaths.

Who is affected?

All warm-blooded animals can become affected. Some animals carry the disease without exhibiting symptoms.

Any person can become infected.

Children under 5 and young adults ages 15-29 are most often affected.

Most deaths occur among the elderly and the immune-suppressed.

What Are the Symptoms?

Diarrhea

Usually watery and sticky

Can contain blood and fecal leucocytes

Fever

Abdominal pain

Nausea and vomiting

Headache

Muscle pain

Are There Long-Term Effects?

Guillain-Barre Syndrome

Immune system attacks own nerves

40% caused by C. jejuni infection

Arthritis, Reiter’s Syndrome

Hemolytic Uremic Syndrome

Septicemia

Leading to infection of nearly any organ, including appendix, abdominal cavity, heart, nervous system, etc.

How Does Campylobacter affect individual cells in the intestines?

Produces a toxin called Cytolethal Distending Toxin (CDT).

CDT activity requires activation of three genes: cdtA, cdtB, and cdtC.

CdtB is nuclease that damages DNA and causes cell cycle arrest.

Causes cell death.

How Does Campylobacter Affect Individual Cells In the Intestines?

What Is the Incubation Period and How Long Does the Illness Last?

Onset of symptoms 2-10 days after ingestion.

Duration of illness 2-21 days, typically 5-7 days.

Relapses occur in 25% of cases.

What are the Diagnostic Tests?

Present in feces of infected individuals

Cultured sample of stool from ill person

Isolation requirements:

Special antibiotic containing media

Microaerophilic atmosphere

5% oxygen

2-10 % carbon dioxide

How is the Illness Treated?

– Most cases

Most infections are usually self-limited.

> 95% of infections clear up on their own.

Affected persons should drink plenty of fluids to avoid dehydration.

Antidiarrheal medications such as loperamide may help symptoms.

How is the Illness Treated?

– Severe cases

Antibiotics used in severe cases of gastroenteritis.

Macrolide antibiotics including Erythromycin are effective and may shorten course of illness.

Resistance developing to Fluoroquinolone antibiotics due to use in poultry feed.

How do people get infected?

Single, sporadic cases

Eating raw or undercooked poultry meat

Fact: Even one single drop of juice from raw chicken meat can infect a person.

Handling raw poultry

Contact with infected fecal matter

How do people get infected?

Outbreaks

Unpasteurized or under-pasteurized milk

Children on class trip drinking unpasteurized milk

Dairy under-processed surplus raw milk for schools.

Cow-leasing program in Wisconsin.

Contaminated water source

Bennington, VT using non-chlorinated water.

How does food or water become contaminated?

Poultry

63-88% of all chickens carry latent infection.

Spread through flock through drinking water and feces.

Spread to meat from intestines during slaughter.

Present in giblets, especially liver.

Milk

Infected udder.

Contact with manure.

Surface water

Infected manure from cows or wild birds.

Enters streams through runoff.

What can be done to prevent Campylobacter infections?

Food Industry

Provide chickens with chlorinated water.

Avoid fecal contamination of udders or milk.

Strictly adhere to pasteurization time and temperature requirements.

Avoid fecal and/or intestinal contamination in meat processing.

What can be done to prevent Campylobacter infections?

Individuals

Avoid drinking unpasteurized milk or untreated surface water.

WASH HANDS!!!

after having contact with pet feces.

after using the restroom or changing a diaper.

What can be done to prevent Campylobacter infections?

Individuals

Use safe food handling practices

Cook all poultry products thoroughly

Wash hands before handling foods.

Wash hands after handling raw foods of animal origin.

Prevent cross-contamination in the kitchen.

What are the latest morbidity and mortality reports?

CDC Morbidity and Mortality Weekly

Published April 30, 2004

“Preliminary FoodNet Data on the Incidence of Infection with Pathogens Transmitted Commonly Through Food — Selected Sites, United States, 2003 “

Published June 28, 2002

“Outbreak of Campylobacter jejuni infections associated with drinking unpasteurized milk procured through a cow-leasing program.” Wisconsin, Nov 10 – Dec 18, 2001.

What is the latest research?

CDC Emerging Infectious Diseases

Published March 2002

“Human Campylobacteriosis in Developing Countries.” Akitoye O. Coker, et al. University of Lagos.

Infection and Immunity

Published July 2001

“CdtA, cdtb, and cdtC form a tripartite complex that is required for Cytolethal Distending Toxin activity.” Maria Lara-Tejero and Jorge Galan. Yale School of Medicine.

What were my sources?

Bad Bug Book: U.S. Food & Drug Administration Center for Food Safety & Applied Nutrition Food borne Pathogenic Microorganisms and Natural Toxins Handbook; vm.cfsan.fda.gov/~mow/chap4.html.

CDC Division of Bacterial and Mycotic Diseases, Disease Information; Campylobacter infections; www.cdc.gov/ncidod/dbmd/diseaseinfo/campylobacter_g.htm.

Campylobacter Facts and Information;
www.foodborneillness.com/ecoli1/campylobacter-overview.htm.

Preliminary FoodNet Data on the Incidence of Infection with Pathogens Transmitted Commonly
Through Food — Selected Sites, United States, 2003;
www.cdc.gov/mmwr/preview/mmwrhtml/mm5316a2.htm.

Outbreak of Campylobacter jejuni Infections Associated with Drinking Unpasteurized Milk
Procured through a Cow-Leasing Program, Wisconsin, 2001;
www.cdc.gov/mmwr/preview/mmwrhtml/mm5125a2.htm.

Nature 403, 665 – 668 (10 February 2000); The genome sequence of the food-borne pathogen
Campylobacter jejuni reveals hypervariable sequences; J. PARKHILL, et al.;
www.nature.com/cgitaf/DynaPage.taf?file=/nature/journal/v403/n6770/full/403665a0_fs.html;


Laboratory‎ > Growth of Bacteria

Liquid media such as broth become cloudy if bacteria are present. This could be the result of only one bacterial cell originally entering the medium, then dividing repeatedly to produce millions!

Bacteria on agar “plates” become visible as distinct circular colonies; each colony should represent an individual bacterial cell (or group) which has divided repeatedly but, being kept in one place, the resulting cells have accumulated to form a visible patch.

Intermediate Food Safety

Intermediate Food Safety

Aims

To explain the causes and effects of food poisoning and its relevance to food safety

Objectives

By the end of the lesson you should be able to:
1.Describe the different types of food poisoning
2.Understand how bacteria cause food poisoning
3.Identify different pathogenic bacteria and their related symptoms

What is Food Hygiene?

The science of preserving health
It involves all measures necessary to ensure the safety and wholesomeness of food during it’s preparation and storage

What does it involve?

Rejecting contaminated food
Decontaminating food
Protecting food from contamination through high standards of personal hygiene, cleaning and disinfection
Preventing any organisms multiplying
Destroying any harmful bacteria by thorough cooking
Discarding unfit or contaminated food

Food Poisoning

Normally associated with symptoms such as diarrhoea and vomiting
May also include headache, stomach cramps and fever
Bacteria are responsible for most cases
Other causes include mycotoxins (poisonous chemicals produced by some moulds)
Food Poisoning (contd.)
Physical contamination:- objects falling in to food – metal, glass, packaging materials etc.
Chemical contamination:- Bleach, cleaning chemicals getting in to food
Natural contamination: Poisonous plants and berries, undercooked red kidney beans
Poisonous mushrooms
The deathcap – one bite can prove fatal
Most food poisoning is caused by?

Bacteria

Types of bacteria

Spoilage: Not particularly harmful bacteria which cause food to go off
Beneficial: “Good Bacteria” which are used to make yoghurt and cheese
Pathogenic: Illness causing bacteria
Spore
A resting resistant phase of some bacteria (including Clostridium Perfingens and Botulinum and Bacillus Cereus). The bacterium produces a protective coat which helps it to survive high temperatures (up to 120°C) and lack of water. When favourable conditions return, the spores split open and release the bacteria which are then able to grow and multiply

Toxins

Moulds and Yeasts
Moulds are a type of fungi that will grow on most foods and at many temperatures. Some are used in food production such as cheese manufacture. Unwanted moulds usually spoil the food but do not cause food poisoning.
Yeasts are another type of fungi that will grow in food. They are used in making food such as bread and beer but also spoil many foods including jam, fruit juice, yoghurts and meats

Food Poisoning bacteria

•Usually need millions of bacteria to cause illness.
•The multiplication of bacteria within the food plays an important part in the disease
Salmonella
Sources – The intestines of ill people and carriers, animals and animal food, raw meat, raw poultry, raw milk, raw eggs, food pests
Common food vehicles – Undercooked or contaminated cooked meat, raw milk and eggs
Onset period – 6 to 72 hours (usually 12 to 36) Endotoxin in intestine (infective food poisoning)
Salmonella
Symptoms – Abdominal pain, diarrhoea, vomiting and fever. Duration is usually one to seven days.
Specific characteristics – Usually requires millions of bacteria to cause illness. Multiplies from 5°C to 47°C under aerobic or anaerobic conditions.
Aerobic and Anaerobic
Bacteria which need oxygen to multiply are classed as aerobic
Bacteria which only multiply without oxygen are called anaerobic
Just to confuse you some bacteria including Salmonella, Staphylococcus aureus and Bacillus cereus are classed as facultative anaerobes which means they can multiply with or without oxygen!
Salmonella
Specific controls
Hygienic farm and abbatoir practices
Avoid cross contamination
Complete thawing of frozen poultry
Thorough cooking to 75°C for one minute
High standards of personal hygiene
Effective cleaning
Safe sewage disposal
Clostridium perfingens
Sources – The intestines of humans and animals, faeces and sewage, soil food pests, raw meat and poultry
Common food vehicles – Rolled joints, casseroles, stews, sauces and meat pies when cooking has removed oxygen
Onset period – 8 to 22 hours (usually 12 to 18) Enterotoxin in intestine. (infective food poisoning)
Clostridium perfingens
Symptoms – Abdominal pain, diarrhoea, (vomiting is rare) and fever. Duration is usually 12 to 48 hours.
Specific characteristics – Usually requires millions of bacteria to cause illness. Multiplies from 10°C to 52°C under anaerobic conditions. At 46°C it can double every 10 minutes. Produces spores. Illness caused from consuming millions of organisms
Staphylococcus Aureus
Sources – Human nose, mouth, skin, hands, spots, boils, septic cuts etc
Common food vehicles – Dairy products. Cold cooked meat and poultry, peeled cooked prawns
Onset period – 1 to 7 hours (usually 12 to 18) Exotoxin produced in food. (Toxic food poisoning)
Staphylococcus Aureus
Symptoms – Abdominal pain, diarrhoea, vomiting. Occasionally subnormal temperatures. Duration between 6 and 24 hours.
Specific characteristics – Usually requires millions of bacteria to cause illness. Toxin may survive boiling for up to 30 minutes. Multiplies from 7°C to 48°C under aerobic or anaerobic conditions. Can tolerate relatively high salt content.
Bacillus Cereus
Sources – Cereals, especially rice, cornflour, spices, dust and soil
Common food vehicles – Reheated rice, cornflour and spices.
Onset period – 1 to 5 hours. Exotoxin produced in food. (Toxic food poisoning)
Bacillus Cereus
Symptoms – Abdominal pain, diarrhoea, vomiting. Occasionally subnormal temperatures. Duration between 12 and 24 hours.
Specific characteristics – Forms spores which produce an exotoxin under aerobic or anaerobic conditions. Both the spores and toxin will survive normal cooking temperatures. Millions required to cause illness. Bacteria multiply between 7°C and 48°C.
Clostridium Botulinum
Sources – Fish intestine, soil and vegetables.
Common food vehicles – Low acid processed food contaminated after canning or vacuum packing. Smoked fish, bottled vegetables.
Onset period –2 hours to 5 days (usually 12 to 36 hours). A heat sensitive neurotoxin produced in the food which affects the nervous system. (Toxic food poisoning)
Clostridium Botulinum
Symptoms – Difficulties in swallowing, talking and breathing. Double vision and paralysis. Diarrhoea followed by constipation. Fatalities are common and survivors may take several months to recover.
Specific characteristics – Forms spores which produce an exotoxin under anaerobic conditions. Both the spores and toxin will survive normal cooking temperatures. Millions required to cause illness. Bacteria multiply between 3.3°C and 48°C.