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83 Cards in this Set
- Front
- Back
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Enterohemorrhagic E. coli.
causes what? |
Bloody diarrhea, and associated with ground meat and unpasteurized juices
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Enterohemorrhagic E. coli. is transmitted by how?
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Transmission is via consuming infected animal products.
Person-to-person transmission can occur & Infection is more common in developed industrialized countries. |
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Enterohemorrhagic E. coli. produce what?
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Shiga toxin which causes: Capillary thrombosis & Blood in stool.
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Digestive infections in developed and undeveloped countries are associated with different pathogens. Name each example.
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Developed countries: Campylobacter Salmonella & Shigella
Undeveloped countries: Vibrio cholerae |
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Clostridium difficile, causes serious gastrointestinal infections, is an example of what?
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Nosocomial infections
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Opportunistic infections are becoming more common. It is caused by what?
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Associated with the overuse of antibiotics.
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Infections in the digestive system are classified in two groups, which are ...?
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Exogenous infections – pathogens that come into the body.
Endogenous infections – organisms that are part of the normal microbial flora. |
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Describe the Exogenous infections.
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Exogenous infections are infections that develop from bacteria normally outside the body that have gained access to the body.
Those bacterias are brought in with contaminated food or water. |
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What are the examples of Endogenous infections?
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Streptococcus and Enterococcus
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Endogenous bacteria causes what?
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Dental diseases.
Infections of the bowel, appendix, and liver. Diverticular abscesses. |
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Most common symptoms for Gastrointestinal infections are ...?:
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Fever, Vomiting, Abdominal pain & Diarrhea
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The nature of the diarrhea is used to classify gastrointestinal infections into three categories, which are ...?
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Watery diarrhea, Dysentery & Enteric fever
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Purest form of watery diarrhea is caused by what?
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By enterotoxin-secreting bacteria: Vibrio cholerae & Enterotoxigenic Escherichia coli
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describe the symptoms of Dysentery.
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赤痢 - Smaller in volume than watery diarrhea. Contain blood and pus. Can be accompanied by cramps and abdominal pain & Little vomiting.
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Describe the Enteric fever and its symptom.
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Prominent features are fever and abdominal pain.
Diarrhea is mild until late in the infection. Most investigated form is typhoid fever, which is caused by Salmonella enterica serotype. Typhoid fever can be serious and result in significant mortality. |
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Endemic Infection is defined as what?
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Infections that occur sporadically, Some are worldwide: some are geographically restricted,there can be seasonal variation & they can be age-related.
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The major pathogens of endemic in developed countries are what?
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Campylobacter, Salmonella & Shigella
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Vibrio cholerae is an example of what?
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Endemic organism geographically restricted to warm climates.
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Epidemic Infection is defined as what?
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Infections involving regional, national, and international populations.
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Most common epidemic infections are what?
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Cholera, Typhoid fever & Shigellosis
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Cholera and typhoid fever are associated with contamination of what?
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Water
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Shigellosis is associated with what?
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Wars, crowding, and poor sanitation. Shigella infection is easily spread.
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Most frequent epidemic infections in the US are what?
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E. coli O157:H7
Cryptosporidium Giardia |
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Food poisoning can result in two ways of what?
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Infection – involves a pathogen directly
Intoxication – involves a toxin produced by a pathogen |
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Bacterial intoxication may involve organs outside the digestive tract. Give an example.
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Botulism (illness caused by botulinum toxin, which is produced by the bacterium Clostridium botulinum under anaerobic conditions) affects the central nervous system.
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Two major pathogens for nosocomial gastrointestinal infections are what?
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Escherichia coli
Clostridium difficile |
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This accounts for 90% of nosocomial gastrointestinal infections.
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C. difficile
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Infection with E. coli O157:H7 can result in renal failure. True or False?
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True. Requires dialysis or transplant.
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Treatment for gastrointestinal infections involes what?
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Treatment involves supportive care with liquid replacement rest.
Substantial liquid loss requires intravenous replacement. |
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What are the adhered bacteria grow and form dental plaque?
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Gram-positive cocci & Gram-positive rods
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Many digestive infections caused by what?
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Enterobacteriaceae.
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Describe the Enterobacteriaceae.
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Diverse family of Gram-negative rod-shaped bacteria.
Spread to the blood can cause endotoxic shock |
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This include some of the largest bacteria known and have a variety of morphologies.
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Enterobacteriaceae
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Shigella and Salmonella are part of the normal flora while E.Coli is not. True or False?
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False: Shigella and Salmonella are not part of the normal flora. E. Coli is the normal colonic flora.
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Enterotoxigenic E. Coli caused by a toxin is the most frequent cause of what?
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Traveler’s diarrhea.
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Transmission of enterotoxigenic E. Coli is by consumption of
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Contaminated food or water.
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Enterohemorrhagi produce what? What is the symptom?
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Shiga toxin which causes: capillary thrombosis (blood clot) & Blood in stool.
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Treatment with which antibiotics for all forms of E.Coli can reduce the duration of illness.
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Trimethoprim/sulfamethoxazole or quinolones are effective.
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Describe the Shigella compared to E. Coli.
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Shigella cannot ferment lactose & Lack flagella.
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Only Shigella dysenteriae produces Shiga toxin. True or False?
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False: all species of Shigella produce Shiga toxin, but S. dysenteriae well know for Shiga toxin.
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Shigella species cause what?
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The most severe form of infection, dysentery.
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Shigella transmission can occur by how?
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Fecal-oral route
Person-to-person transmission Consumption of contaminated food or water. |
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Describe the pathogenesis of Shigella.
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Shigella is a genus of Gram-negative, non-spore forming rod-shaped bacteria.
Acid-resistant; that is it survives passage through the stomach. Invade the cells of the colonic mucosa. |
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Name the antibiotics for Shigella which are effective at shortening the period of illness.
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Trimethoprim and sulfamethoxazole are the drugs of choice.
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Salmonella infections are divided into five groups of what?
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Bacteremia
Enteric fever Chronic infections Gastroenteritis Typhoid fever |
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What is an acute form of gastroenteritis?
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Salmonella Bacteremia
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Approximately 70% of AIDS patients are affected by this, which can lead to septic shock and death.
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Salmonella Bacteremia
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What is a multiorgan salmonella infection with sustained bacteremia & profound infection of organs?
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Enteric fever
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Describe the symptoms of enteric fever?
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Sustained bacteremia & Profound infection of organs: lymph nodes, liver, and spleen- First symptoms are fever and headache
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Chronic infection cause by Salmonella is very serious if ...?
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If bacteria enter the blood & continuous release of endotoxin can lead to myocarditis, encephalopathy, intravascular coagulation, etc.
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Salmonella gastroenteritis occurs where in the body?
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Both in the stomach (gastro) and intestines (entero).
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Salmonella gastroenteritisis occur where?
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Disease of industrialized societies.
Results from improper food handling. |
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Salmonella gastroenteritisis is transmitted by how?
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Transmission is from animal or human reservoirs to humans.
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Gastrointestinal Salmonella is the leading cause of what?
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Food-borne gastrointestinal infections caused by poultry and infected eggs are most often the cause.
Poor food handling and preparation are also implicated. |
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Typhoid fever is caused by what?
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Caused by Salmonella enterica serotype Typhi.
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Typhoid fever is transmitted by how?
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Transmitted to water after sewage contamination.
Passed from human to human by the fecal-oral route |
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Why can S. enterica serotype Typhi survive for long periods inside viable host macrophages?
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- Inhibits the release of oxidative poisons used by macrophages
- Allows it to multiply and infect new macrophages - Bacteria eventually spill into the lymphatic circulation. - Migrates to lymph nodes, spleen, liver, and bone marrow. |
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Describe the bacteria Vibrio cholerae.
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Vibrio cholerae, a Gram-negative, non spore-forming, and rod-shaped
Commonly found in salt water. Have a unique morphology - form S shapes and half spirals. Highly motile by means of a single polar flagella.Vibrio cholerae produces a toxin. Causes a devastating intestinal infection |
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Vibrio cholerae produces what?
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Toxin which causes a devastating intestinal infection.
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How is Vibrio cholerae spread?
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Spread primarily by contaminated water and poor sanitation.
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Describe the pathogenesis of Vibrio cholerae.
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Short incubation of 2 days
Bacteria possess long filamentous pili used for colonization, which is colonizing the entire intestinal tract. |
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What is the major clinical problem about Vibrio cholerae infection?
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Liquid loss is the major clinical problem and depends on bacterial growth, toxin production & host liquid secretion and absorption.
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Vibrio Cholerae causes stools to become watery, voluminous, and almost odorless & can progress to what?
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Rice stool containing mucus
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What is the treatment of Vibrio Cholerae?
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Liquid replacement
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What is caused by Campylobacter jejuni?
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Campylobacter Enteritis
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Primary reservoir of Campylobacter jejuni is what?
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Animals, and then transmitted to humans.
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Most common source of Campylobacter jejuni is what?
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Undercooked poultry.
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Describe the morphology of Helicobacter pylori.
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Slender
Microaerophilic Gram-negative curved rod Polar flagella |
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What is the difference in Helicobacter pylori compared to other Gram-negative bacteria?
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Lipopolysaccharides in the outer layer may be more toxic than those in other Gram-negative pathogens.
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What is a unique feature of Helicobacter pylori?
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The production of a urease, an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia.
Ammonia allows the bacteria to survive in very acidic environments. |
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Helicobacter pylori produces a circulating protein called ...?
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Vacuolating cytotoxin which causes massive vacuolar degeneration of cells.
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Vacuolating cytotoxin causes what in eukaryotic cells?
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apoptosis which is the process of programmed cell death (PCD) that may occur in multicellular organisms.
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Infected cells by Helicobacter pylori have what?
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Large vacuoles (caused by vacuolation) throughout their cytoplasm.
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Helicobacter pylori infection causes what disease?
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Ulcers
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Describe the symptoms of Helicobacter pylori.
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Primary infection shows no symptoms or some nausea and mild upper abdominal pain, which usually lasts two weeks.
Gastritis or peptic ulcer disease can develop years later. |
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Describe the mechanisms of Helicobacter pylori to adhere to the gastric mucosa and survive the acidic environment.
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- Highly motile and swims to less acidic areas. In less acidic areas, it adheres using surface proteins.
- Colonization is usually accompanied by cellular infiltration (migration of cells from their sources of origin); part of the inflammatory response. |
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Treatment for Helicobacter pylori is what?
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Treatment with bismuth salts and a combination of tetracycline plus clarithromycin cures 95% of cases.
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What is the most common sign of viral infection and describe it.
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Diarrhea
Rapid onset – within hours Lasts for less than three weeks Abundant excretion of virions in the stool |
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Hepatitis describes any disease that ...?
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Affects the hepatocytes of the liver.
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Liver diseases can be caused by a variety of agents such as ...?
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Bacteria
Protozoans Viruses Toxins Drugs |
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C. difficile and other exogenous infections are frequently acquired in where?
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In hospital environments
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Helicobacter pylori spreads through what?
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Oral-oral or fecal-oral contact
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Exogenous infections can cause diarrhea within 2 hours. True or False
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False: nausea and vomiting within 6 hours
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