GI&HB Week Three

A form of liver disease observed in middle-aged patients with abnormal liver biochemical test results and histologic evidence of alcoholic hepatitis but no history of alcohol abuse

The causes of NAFLD may be divided into two main categories. What are they?

What condition is most often reported associated with NAFLD?

In regard to obesity-related NAFLD development, which is more important, the distribution of body fat or the total adipose tissue mass in the patient?

What is the hallmark histologic feature of NAFLD?

What are the two primary pathogenic factors in steatosis in most patients with NAFLD?

How does NAFLD usually present?

What is the advanced form of NAFLD?

In contrast to NAFLD, this is a localized or patchy process that stimulates a space-occupying lesion in the liver on imaging studies

What is the main contributer to the amino acid pool?

In a mature adult, the Nitrogen Balance should be....?

In what situations should there be a positive nitrogen balance (nitrogen intake > nitrogen excretion)?

In what situations should a negative nitrogen balance (nitrogen intake < nitrogen excretion) exist?

What are the essential amino acids?

What are the nonessential amino acids?

What are the conditional non-essential acids, and what essential acid are they derived from?

Where does protein degradation begin, and what is the main protease involved?

What activates the zymogen pepsinogen to form the active pepsin protease?

For protein degradation in the intestine, what enzyme is responsible for the activation of the zymogen Trypsinogen? Where is this enzyme derived from?

For protein degradation in the intestine, what enzyme is responsible for the activation of the zymogen Chymotrypsinogen? Where is this enzyme derived from?

For protein degradation in the intestine, what enzyme is responsible for the activation of the zymogen Procarboxypeptidase? Where is this enzyme derived from?

For protein degradation in the intestine, what enzyme is responsible for the activation of the zymogen Proelastase? Where is this enzyme derived from?

When trypsin becomes abnormally activated in the pancreas, what molecule is responsible for binding to and inhibiting the active trypsin?

Where does Trypsin cleave?

Where does Chymotrypsin cleave?

Where does Elastase cleave?

Where does Carboxypeptidase A cleave?

Where does Carboxypeptidase B cleave?

From what end of the small peptide particle does Aminopeptidase cleave?

From what end of the small peptide particle does Carboxypeptidase cleave?

What is the most common genetic disease of amino acid transport?

This is an AR disease characterized by a defect in the absorption of basic amino acids in kidneys and liver

What are the symptoms of Cystinuria?

What is the treatment for Cystinuria?

What are the four basic amino acids deficiently absorbed in Cystinuria?

This disorder is an AR disease characterized by a defect in the absorption of neutral amino acids in kidneys and intestine (major mediator of tryptophan uptake)?

What are the symptoms of Hartnup Disorder?

What is the treatment for Hartnup Disorder?

What cells secrete HCl?

HCl is required for Chief Cells to secrete what?

In the intestine, what absorbs the amino acids?

What can impair the release of HCl into the stomach?

What can cause a failure of pancreatic zymogen cleavage? What can this cause? How can it be treated?

True or False:
Statin treatment is safe and can improve liver tests and reduce cardiovascular morbidity in patients with mild-to-moderately abnormal liver tests that are potentially attributable to non-alcoholic fatty liver disease.
True False

What is the most common cause of abnormal liver tests in the developed world?

NAFLD and Non-Alcoholic Steatohepatitis (NASH) may be independent risk factors for what type of disease, which is classified as the main cause of death in these patients?

What percentage of patients in developed countries have Fatty Liver or Non-Alcoholic Steatohepatitis (NASH)?

Is ALT testing specific to the liver?

What is the most common monosaccharide found in humans?

How are monosaccharides classified?

Monosaccharides are classified according to the most oxidized functional group. If it is an aldehyde, what is it called?

Monosaccharides are classified according to the most oxidized functional group. If it is a ketone, what is it called?

Monosaccharides that have the same chemical formula, but different structures are called?

A specialized type of isomer in which the structure is varied around a single carbon is called?

If the single carbon that isomers are varied around happens to be the carbonyl carbon, then the two compounds are called?

Anomers of glucose are in equilibrium so that in our bodies, glucose is 2/3 __________ anomer and 1/3 _________ anomer

Monosaccharides that are mirror images of each other are called?

An example of glucose enantiomers is D-glucose and L-glucose. Our cells can use __________ in metabolic pathways, but cannot use ________

What are monosaccharides linked by?

True or False:
All monosaccharides are reducing agents
True False

True or False:
All dissaccharides are reducing agents
True False

What is an example of a reducing dissacharide?

What is an example of a non-reducing dissarcharide?

Where does digestion of carbohydrates begin?

What enzyme begins digesting plant starches and animal glycogen in the oral cavity?

What are the major dietary complex carbohydrates?

What stops salivary alpha-amylase activity when it reaches the stomach?

When the stomach contents enter the small intestine, the pH is neutralized by the secretion of what from what organ?

What enzyme is secreted into the small intestine to further digest the oligosaccharides?

What does pancreatic amylase in the small intestine break the oligosaccharides down into?

The final stage of dissacharide digestion occurs by the action of...?

What are the 5 major dissacharidases?

What results from digestion of the dissacharides by dissacharidases in the intestinal mucosa?

The monosaccharides that result from digestion by the dissarcharidases are absorbed by....?

What are the two mechanisms by which the monosaccharides that result from digestion of disaccharides in the small intestine absorbed by the intestinal cells of the duodenum and upper jejunum?

What is the active transporter protein responsible in part for the absorption of monosaccharides into the duodenum and upper jejunum? What is it dependent on?

How are the monosaccharides absorbed by the small intestine transported during faciliated diffusion?

Glucose and Galactose are transported across the brush border in the duodenum and upper jejunum by which transport process?

Fructose is transported across the brush border in the duodenum and upper jejunum by which transport process?

What is the facilitative diffusion transporter involved in the absorption of monosaccharides into the small intestine?

Abnormalities in the degradation of dissacharides can lead to digestive problems. What results from a deficiency of lactase? What are its symptoms? How can it be treated?

Abnormalities in the degradation of dissacharides can lead to digestive problems. What deficiency results in an intolerance to sucrose? How can this be treated?

Triacylglycerol degradation is carried out by ....?

Pancreatic lipase can be inhibited by high concentrations of what?

During triacylglycerol degradation, a second protein, _______, helps to anchor the pancreatic lipase to the lipid/aqueous interface facilitating enzymatic activity

Cholesteryl ester degradation is carried out by _______ which removes the free fatty acid from the 3-hydroxyl group

Cholesterylesterase is activated by the presence of what?

Secretion of the digestive enzymes that degrade dietary lipids is under hormonal control. The mucosal cells in the duodenum and jejunum secrete the peptide _________, which is responsible for this digestion

What are the three main functions of CCK?

What hormone signals the liver and pancreas to secrete bicarbonate to neurtralize the gastric contents (chyme)?

This consists of digested lipid products and bile salts to form an amphipathic particle. This particle has a hydrophilic outer surface and a hydrophobic core

What part of the mixed micelle allows the digested lipid materials to be transported through the unstirred water layer that separates the mucosal membrane from the bulk fluid contents of the intestine?

What is found in the interior of the mixed micelle?

What occurs once the contents of the mixed micelle are taken up by the intestinal cell (enterocyte)?

What is the first step in the resynthesis process of triacylglycerol and cholesterol esters?

What is used for the glycerol backbone for triacylglycerol synthesis?

Malabsorption of lipids leads to increased fat content of fecal material. What is this called, and what can it cause?

What are complex lipids formed in the enterocytes synthesized into?

Throughout the length of the GI tract, the wall of the gut can be divided into four layers. What are they?

What is the inner layer of the digestive tract?

The luminal surface of the gut is lined by a layer of epithelium that is moistened by glandular secretions. What lies deep to the epithelium?

This is a layer of loose connective tissue that is rich in blood vessels, nerves, and lymphatic ducts.

In most regions of the GI tract, lying in the outer region of the lamina propria (away from the lumen) is a thin layer of smooth muscle called the ...?

Contractions of the muscularis mucosa affect the folding of the epithelial surface into ridges called ______ (stomach) and _______ (intestines)

What cell type secrete various signaling molecules into the lamina propria where they can: 1) act as hormones by entering the blood stream; 2) activate neural reflexes by acting on nerves in the lamina propria; 3) act as paracrine compounds by acting on nearby cells in the epithelial layer and lamina propria; or 4) have an autocrine action by providing feed-back to each other

What is the double layer of smooth muscle (inner circular and outer longitudinal) that lies outside the submucosa?

What are the sheets of smooth muscle of the Muscularis Externa necessary for?

What ganglionated plexus lies between the longitudinal and circular muscle layers of the Muscularis Externa and regulates the actions of the smooth muscle layers?

What is the ganglionated plexus of nerves located in the Submucosa called?

Within the peritoneal cavity, the structures of the digestive tract are covered with a sheet-like serous membrane comprised of a monolayer of mesothelial cells. What is this known as?

A dense network of collagen fibers, referred to as ________, envelops GI structures that are retroperitoneal, as well as the upper regions of the GI tract from the oral cavity to the esophagus as it passes through the diaphragm. It attaches these regions of the digestive tract to adjacent structures.

What are the muscle layers of the small intestine?

The motor function of the longitudinal and circular muscle layers of the small intestine is coordinated by?

The motor function of the muscularis mucosa and epithelial function of the small intestine are regulated via the?

What is the primary function of the intestine?

This is most commonly caused by an adverse mucosal response to dietary gluten which is present in wheat- or rye-based foods. It results in a stunting of the villi and a decreased absorptive mucosal surface area.

What is the primary site of nutrient absorption?

What is the primary function of the small intestine?

Within the small intestine, what cell type tends to be absorptive?

Secretion of fluids and electrolytes occurs in the small intestine. What cell type are responsible for secretion?

What are the two routes of epithelial transport in the small intestine?

The permeability of tight junctions varies depending on location in the GI tract. Are they tight or loose in the small intestine?

What are the four methods of sodium transport across enterocytes?

Water movement in the intestine is passive and relies on what three things?

Describe calcium transport across the enterocyte?

There are at least two methods of Iron uptake, one for __________ and a second for __________

Free iron is toxic when it enters the cell, so it binds to _______ to form __________

How does absorbed ferritin exit the enterocyte, and where does it go?

How is chloride secreted from crypt cells in the small and large intestine?

What stimulates anion secretion? What mediates it?

What stimulates fluid secretion? Where is this particularly important?

Increased interstitial hydrostatic pressure, also called secretory filtration, may accompany what?

The small intestine is involved in the breakdown and assimilation of three important food components. What are they?

Emulsified fat products must first pass through two barriers:

What are the components of the mixed micelle?

Efficient absorption of fat-soluble vitamins requires what?

What happens to the intestine when longitudinal muscle contracts?

What happens to the intestine when circular muscle contracts?

What does postprandial mean?

When do interdigestive patterns occur?

What type of contractions promote forward movement of luminal contents in the small intestine?

What type of contractions promote mixing with no net forward movement of luminal contents in the small intestine?

What provides contact between smooth muscle cells and allows for coordinated contractions?

Circular smooth muscle cells in the small intestine are characterized by rhythmic episodes of spontaneous depolarization of 5-15 mV in amplitude lasting 1-5 sec. These are called what?

What happens if slow waves reach threshold?

What are the action potentials or spikes of slow waves due to?

Is the strength of contractions in the small intestine determined by the number of spikes or their amplitude?

Where do propagating slow waves originate in the small intestine?

What are the pacemakers of the gut?

Slow waves do not directly produce contractions and are propagated from cell to cell via _________

What is the primary neurotransmitter released from intrinsic nerves associated with the longitudinal muscle?

What is the primary neurotransmitter associated with circular smooth muscle?

A large portion of the increase in intracellular calcium in smooth muscle is derived from an influx of __________ calcium. In contrast, in skeletal muscle calcium is mobilized from _________ stores.

The contractions of the small intestine serve to:

The frequency of slow waves varies along the upper GI tract. What are the frequencies per minute in the stomach, duodenum, and ileum?

This is a motor phenomenon that occurs in the small intestine during the interdigestive period

MMC migration requires what two things?

What are the three phases of the MMC, and what do they entail?

What does phase III activity of the MMC do?

What terminates the MMC?

These type of contractions displace chyme in an oral and aboral direction. The forces for this are exerted by the circular muscle layer only.

What is the most common type of contraction following a meal?

This says that stimulation (e.g. distention by a bolus) at one locus of the small bowel induces contraction above and relaxation below the point of stimulation

The Law of the Intesine or Peristaltic Reflex is mediated by the?

This occurs when distension of one segment of small bowel reflexively inhibits the contractile activity of other segments

This is a state of no muscle contractility. Electrical slow waves are present but there is little or no spike activity. This results from continuous activity of the intrinsic inhibitory neurons and is caused by peritoneal irritation

This is the opposite of ileus in that there is no activity of the inhibitory neurons. The syncitial properties of the intestinal smooth muscle cells and their inherent contractility then produce maximal contractions

Name the Protozoan:
Disease: Amebiasis/Amebic Dysentery/Liver Abscesses
Epidemiology: Worldwide; male homos in US; trop and subtrop climates
Symptoms:
85-90% pts asymptomatic
2-21 day incubation period
Variable or chronic intestinal symptoms (GI upsets, including colitis & diarrhea)
Very Severe Cases: ulcers; ameboma; perforation; hemorrhage; fulminant, bloody diarrhea; intestinal hemorrhages & dysentery; Amebic hepatitis = single abscess in right lobe (RUQ pain, fever, weight loss)

How is it transmitted?
How is it diagnosed, treated, and prevented?

What are the differences between Amebic and Bacillary Dysentery?

Identify the Protozoan:
Epidemiology: Worldwide; common in hikers who drink unfiltered water
Symptoms:
Organism is non-invasive, but destroys epithelial microvilli
Acute Infections: 2-21 day incubation period; severe diarrhea, but no dysentery; greasy, fatty, foul-smelling stools; abdominal distension w N&V
Chronic Infections: Low antibody titers; diarrhea, weight loss, and intestinal malabsorption; flatulence

How is it transmitted?
How is it diagnosed, treated, and prevented?

Identify the Protozoan:
Disease: Cryptosporidiosis
Epidemiology: Worldwide; outbreaks in US due to inadequate water purification
Symptoms: Abdominal cramping with watery, non-bloody stool
Opportunistic Infection: chronic diarrhea, severe fluid loss, malnutrition, can be fatal

How is it transmitted?
How is it diagnosed, treated, and prevented?

Identify the Protozoans:
Disease: Coccidiosis
Epidemiology: Worldwide; outbreaks in US due to inadequate water purification
Symptoms: Mild to severe diarrhea with varying degrees of abdominal cramping, gas, fever, nausea, and vomiting

How are they diagnosed, treated, and prevented?

Identify the Helminth:
Epidemiology: Worldwide, mostly southern US
Symptoms: Largely asymptomatic; weakness and diarrhea

How is it transmitted?
How is it diagnosed, treated, and prevented?

Identify the Helminth:
Disease: common tapeworm in pets that can be passed to humans
Epidemiology: worldwide
Symptoms: Mostly asymptomatic; diarrhea & pruritis

How is it transmitted?
How is it diagnosed and treated?

Identify the Helminth:
Epidemiology: Worldwide; predominantly tropics; 2.2 mil cases/yr in US
Symptoms: Mostly asymptomatic; Abdominal pain; Diarrhea; Rectal Prolapse

How is it transmitted?
How is it diagnosed, treated, and prevented?

Identify the Helminth:
Epidemiology: Worldwide; most common human helminth infection
Symptoms:
Acute infections are asymptomatic
Moderate to heavy infections can cause abdominal pain and intestinal obstruction
Adult worms may cause bile tract obstruction
Migrating worms can cause pulmonary problems including eosinophilia, pneumonia, and cough
Malnutrition in children in developing countries

How is it transmitted?
How is it diagnosed, treated, and prevented?

What is the most common human helminth infection?

Identify the Helminth:
Epidemiology: worldwide; tropics, southern US
Symptoms: 1/3 cases are asymptomatic
Skin penetration may cause a pruritic papular erythematous rash ("ground itch")
Pulmonary complications during lung migration (Loffler's syndrome)
Burning or colicky abdominal pain, diarrhea with passage of mucosa.
Nausea, vomiting, and weight loss Immunocompromised patients are more likely to suffer from autoinfection.
Presents with abdominal pain, distension, shock, pulmonary and neurologic complications and septicemia.
Can be fatal

How is it transmitted?
How is it diagnosed, treated, and prevented?

Identify the Helminths:
Disease: Hookworm disease
Epidemiology: Africa, Asia, Americas; Americas and Australia
Symptoms:
Skin penetration may cause a pruritic papular erythematous rash ("ground itch")
Iron deficiency anemia and other nutritional disorders caused by worm attachment to intestine
Abdominal pain, diarrhea, weight loss due to adults residing in small intestine where they attach and feed on blood
Pulmonary eosinophilia during lung migration (Loffler's Syndrome)

How is it transmitted?
How is it diagnosed, treated, and prevented?

Identify the Helminth:
Disease: pinworm, seatworm, enterobiasis
Epidemiology: worldwide; most common helminth infection in US
Symptoms:
Children are most often infected but infection is typically asymptomatic
Perianal pruritis (nightime) leading to excoriations and bacterial infections.
Anorexia, irritiability, and abdominal pain
In rare cases causes peritoneal granulomas and vulvovaginitis (bacterial, Trichomonas, and Candida)

How is it transmitted?
How is it diagnosed, treated, and prevented?

What are the three primary functions of the large intestine?

What digestive enzymes are secreted from the colon, and where does nutrient absorption take place in this organ?

The longitudinal muscle of the colon is concentrated into three bands. What are these called? Due to this, the circular muscle has the appearance of bulging outwards in sacculations called what?

Why is transit time so much slower in the colon than in the small intestine?

What are the most common motility patterns in the colon, and where do they occur?

In the colon, ______ migration results in a net movement of chyme in an aboral direction. In this case slow waves are associated with long bursts of spike activity.

The _______ anal sphincter is composed of smooth muscle which is tonically contracted. Activation of the parasympathetic nerves relaxes it via the release of VIP while activation of sympathetic nerves causes it to contract.

The ________ anal sphincter is composed of skeletal muscle and receives excitatory innervation from the pudendal nerve. It is under voluntary control.

Defecation is initiated by mild distension which activates the __________ reflex which relaxes the internal anal sphincter and elicits the urge to defecate.

During defection, mild distension of the rectum induces a reflexive contraction of the external anal sphincter, termed __________.

Defecation is facilitated by voluntary contraction of the abdominal muscles. What is this termed?

The intrinsic innervation of the colon produces a net ________ influence on the muscular layers.

The proximal colon receives extrinsic ________ innervation from both the vagus and the pelvic nerves. _______ stimulation causes segmental contractions; _______ nerve stimulation causes propulsive activity in the distal colon.

Sympathetic innervation to the proximal colon is via the _______ nerves. In the distal colon it is the _________ colonic nerves, although these fibers are associated with the entire colon.

The large intestine absorbs ____, _____, and _______ and secretes _______ and _______.

Are the intercellular spaces smaller or larger in the colon compared to the small intestine?

How does the colon absorb Na?

Two or more of the following for 3 months or more is classification for what?

Straining more than 25% of the time
Hard stools more than 25% of the time
Incomplete evacuation more than 25% of the time
Two or fewer bowel movements in one week

What are some of the common constipating drugs (4)?

What is an important aspect of the physical exam for constipation? What other screening methods are used?

What are the treament options for constipation (general)?

What type of diarrhea persists with fasting and has no osmotic "gap"?

Which type of diarrhea disappears with fasting and is characterized by nonabsorbed ions?

Which diarrhea type is characterized by:

Stool (Na) > 90 and
Osmotic Gap of < 50

Which diarrhea type is characterized by:

Stool (Na) < 60 and
Osmotic Gap >100

What is the single most common cause of Osmotic Diarrhea? What are some other possible causes?

What are some common causes of Secretory Diarrhea?

What is the typical duration of an acute diarrhea? Acute diarrheas are usually infectious. What is the most common culprit?

What are the danger signs associated with acute diarrheas (7)?

When treating acute diarrheas with antibiotics for a suspected parasite, we dont typically wait for the culture to come back. Instead, what are the first through 4th lines of treatment often used?

What is the first line of defense for C. Diff? Due to resistance, what is the second line of defense that is more costly, but has no known resistance?

How long does it typically take C. Diff patients to respond to antibiotics?

What is the most common type of Chronic Diarrhea?

What are the treatment options for Nonspecific Chronic Diarrhea?

What is the most common cause of severe diarrhea among young children worldwide?

What is the mode of transmission of Rotavirus?

What is the diagnosis?
These are non-enveloped, triple-layer viruses, segmented dsRNA (11 segments), RNA genome. They cause viral gastroenteritis, and typically infect the intestines in children of age 6 months-3 years. The diarrhea results in fluid loss and severe dehydration.

Associated Symptoms:
Watery stools and vomiting after a 1-2 day incubation period in young children
Vomiting is common and may be prolonged
High, urine-specific gravity and metabolic acidosis
Usually no blood or fecal leukocytes

True or False:
Natural rotavirus infection efficiently protects against severe disease associated with re-infection.
True False

These are single stranded, positive sense RNA. Naked.
Major cause of non-bacterial diarrhea in children (> 2 years) and adults.
Most common cause of epidemics of viral gastroenteritis
Associated Symptoms:
Watery Diarrhea
Nausea
Projectile Vomiting
Cramps
Fever
Headache
Malaise

What is the diagnosis?

What is the most common cause of epidemics of viral gastroenteritis in schools, camps, cruise ships, etc?

Do noroviruses have long term protection, or is re-infection possible?

These are ss, + sense RNA viruses, naked, icosahedral capsid.
Most commonly affect children under 2, but also elderly and immunocompromised.
Transmission appears to be person to person, fecal-oral.
Symptoms manifest 2-3 days post-infection
Disease usually lasts only a few days.
Symptoms very similar to rotavirus but not as severe.

Crohn's Disease has been associated with polymorphisms in what three genes, which contribute to the function of the innate immune system and the process of autophagy?

Patients with Crohn's Disease are more likely to have anitbodies to (3)?

50-80% of Ulcerative Colitis patients have what antibodies?

What is the diagnosis?:

A chronic, recurrent, usually focal, asymmetric and transmural inflammation of the GI tract, which may effect any portion of tract but most commonly small bowel and colon.
Symptoms/Complications: diarrhea, pain, weight loss, malabsorption, fistula and strictures, abscesses, and anemia

If a Crohn's patient has this symptom, it means that the disease will be hard to treat. What is the symptom?

What is the diagnosis?:

Chronic inflammatory condition of the colon characterized by inflammation of the mucosa resulting in ulceration, characterized by abdominal pain and diarrhea (usually bloody). Proctitis may result in tenesmus, bleeding. Has a contiguous spread.
Symptoms: bloody diarrhea, abdominal pain, tenesmus, and, in severe disease, tachycardia, fever, and anemia.

What two extraintestinal manifestations of inflammatory bowel disease have a course that follows the course of the disease?

What extraintestinal manifestation of inflammatory bowel disease, characterized by bile duct inflammation resulting in fibrosis, is associated with an increased risk of colon cancer and choangiocarcinoma?

What are the two goals of treatment for inflammatory bowel disease?

What is the main non-surgical treatment for Ulcerative Colitis?

What is the best non-surgical treatment for Crohn's Disease?

What is this characteristic of?

Perceived disturbance in GI function without structural or biochemical abnormalities by objective testing.
Sensorineural motor dysfunction
Low level inflammation without end organ damage

What type of probiotics are used for IBS?

What is the most common cause of food poisoning in the US?

What is the diagnosis:
Gram-positive coccobacillus
Typically transmitted through food that requires hand preparation
Virulence factors are several toxins which are produced by the organism that induce projectile vomiting
Typically occurs within hours of eating contaminated food
Diarrhea almost never occurs
Toxins are heat stable and directly cause release of serotonin in the intestine that results in vomiting

How can Staph Aureus be differentiated from Norwalk virus?

What is the diagnosis?:

Gram positive rod
Two types of food poisoning
Type I: often a quick onset (2-3hrs), typically after ingesting starchy food. Causes vomiting through a heat-stable toxin
Type II: caused by ingestion of contaminated meat or veggies and the organism produces a heat-labile toxin that causes diarrhea in 10-12 hours after ingestion

Virulence factors are several toxins which are produced by the organism that induce vomiting, often projectile.

What is the diagnosis?:

Gram-positive rod
Causes abdominal cramping and watery diarrhea within 8-12 hours of ingesting infected food
Produces heat resistant spores that are not killed by cooking.

Virulence factors is an enterotoxin
The diagnosis is usually suspected when a local outbreak of the disease has occurred.

What is the diagnosis?:

Gram-positive rod
Mostly found in people that have ingested improperly home-canned veggies or sausage
Very rare
Causes death in ~30% of infected individuals

Virulence factor is a toxin that takes 1-2 days after ingestion for symptoms to occur, because the toxin must spread from the intestine to the nerve synapses
Only food borne disease that takes more than 12 hours from ingestion to symptom onset
Symptoms are severe and include blurred vision followed by bilateral descending, flaccid paralysis
Death is typically caused by respiratory failure

What is the only food borne disease that takes more than 12 hours from ingestion to symptom onset?

Which two forms of Escherichia coli cause "traveler's diarrhea"?

Which form of Escherichia coli causes a heat-labile and heat-stable toxin which causes watery diarrhea? Disease lasts ~ 24 hours.

Which form of Escherichia coli causes disease by binding the mucosal cells of the intestine and then killing the cells, which leads to watery diarrhea. Disease does not typically resolve for several days.

Which form of Escherichia coli does not produce a toxin, but rather injects proteins into the mucosal epithelial cells that leads to watery diarrhea. This causes a mild form of the disease and seems to be restricted typically to children 6 months of age or less

What is the diagnosis?:

Typed using O antigen (139 serogroups): serogroup O1 (classical or El Tor; casuses pandemics); Non-O1 (cause less severe disease); recent Bangledesh outbreak (O139 "Bengal")

Non-inflammatory, enterotoxic disease
Causes massive efflux of fluid (up to 20 L/day)
Symptoms are due to dehydration

Primary virulence factor: 2-component toxin (AB toxin)

Incubation time: 7-14 days
Then, sudden onset of massive diarrhea ("rice water stool"); contains large numbers of organisms. Dehydration and shock can follow. Mucosa remains intact, no invasion.

What is the diagnosis?:

Thin, Gram-negative rod; non-motile
Serogroups: S. flexneri; S. sonnei

Symptoms: causes bacillary dysentery, invasive (gets into cells of large intestine), abdominal pain

Route of transmission: fecal-oral

Most cases are children < 5 yrs; outbreaks are long lasting

Virulence factor is Shiga Toxin

What is the diagnosis?:

Causes self-limiting gastroenteritis
Dysentery type mechanism
Symptoms last from 2 days to a week and resolve spontaneously
Can be transferred to humans by reptiles, such as turtles

What bacterial agent is motile by peritrichous flagella?

What is the diagnosis?:

Prototype Enteric Fever
Typhoid Fever
Penetrating Disease--can penetrate through intestinal wall

Humans are sole carriers
Route of transmission is by ingestion of contaminated food and water
Incubation time is about 10-14 days

Symptoms, Week 1: Lethargy, fever, malaise, general aches and pains, constipation
Symptoms, Week 2: severely ill, sustained temp of 104, Diarrhea, Rose Spots

Diagnosis requires isolation from blood, two vaccines are available, and antimicrobial therapy is necessary

What is the diagnosis?:

Causes acute enteritis
Common cause of human bacterial gastroenteritis
Zoonotic disease: most infections are due to ingestion of contaminated food and water, esp. chicken and turkey

Affects young children
Causes illness in all ages

Incubation time: 3-5 days
Low infective dose
Severe abdominal pain with fever, can mimic acute appendicitis, dysentery, usually self-limiting

Incubates at 42 degrees celcius

Anti-microbial therapy is used for treatment

EHEC can cause a severe life-threatening illness that most commonly strikes children under 5 and the elderly. It destroys RBCs, causing acute kidney failure. Treatment is blood transfusion. What is the illness?

Other than HUS, what other life-threatening illness can be caused by E. coli?

What form of E. coli can cause severe life-threatening illnesses, such as HUS and CNS problems, as well as the non life-threatening dysentery. This form is linked to the powerful Shiga toxin, causing severe abdominal cramps, dysentery, vomiting, and nausea. However, there is NO FEVER present. Incubation time is 4-8 days, and duration of illness is 5-10 days.

What is the most common cause of pseudomembranous colitis?

What is the diagnosis?:

Gram-positive rod
Can survive at low temps, and often transmitted in soft cheeses, processed meats, even when properly refrigerated

Symptoms include fever, muscle aches, nausea, and diarrhea

Organism is an intracellular pathogen and can travel to the nervous system where symptoms include HA, stiff neck, loss of balance, confusion, and convulsions

The bacteria release toxins and other proteins in the intracellular niche they reside and use these invaded cells to help them traffic to other parts of the body.

Treatable with antibiotics

Jaundice is not usually seen until bilirubin exceeds ___mg/dL