Micro J210 Gram Negative Enterics
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What is diarrhea?
- -Loose watery stools more than three times in one day which might be associated with cramps, bloating, nausea, and an urgent need to have a bowel movement
- -Acute diarrhea has generally linked to a bacterial, parasitic infection, viral or food intolerance. Whereas chronic diarrhea has been associated with functional disorders for instance IBS
What are the types of diarrhea?
What is secretory (watery) Diarrhea?
means that there is an increase in the active secretion or there is an inhibition of absorption. There is little to no structural damage (ex diarrhea seen in cholera patients)
What are the exudative diarrhea?
- -Exudative plus blood is dysentery
- -Refers to the presence of blood and pus in the stool. This occurs with inflammatory bowel diseases like Crohns disease or ulcerative colitis or infections (Shigella infection)
What is an enteric?
- -Rod shaped gram negative bacteria, most occur normally or pathogenically in the intestines of humans and animals.
- -There are 7 common enterics
Which enteric is not rod shaped?
-Vibrio, short helically shaped rod
Which enterics are not motile?
-Klebsiella and shigella
What is a enterobacteriacease?
- A family of gram negative bacilli that contains more than 100 species of bacteria that normally inhabit the intestines of humans and animals
- -E. coli, Klebsiella pneumoniae, salmonella typhi, and shigella dysenteriae
What are coliforms?
- Enterobacteriacease that are commonly part of the normal intestinal tract flora
- -E.coli and klebsiella pneumoniae
What are the 7 enterics and are what are the family they are from?
- 1. E. coli- Coliforms/enterobacteriacease
- 2. Klebsiella pneumoniae-Coliforms/enterobacteriacease
- 3. Salmonella typhi- Enterobacteriacease
- 4. Shigella dysenteriae- Enterobacteriacease
- 5. Vibrio Cholera- vibrionaceae family
- 6. Campylobacter jejuni- no family
- 7. Heliobacter pylori- no family
What is the role of gene transfer in enterics?
- -Conjugation and transduction (bacteriophage)
- -These bacteria are very efficient in exchanging genetic information for resistance to antibiotics (r factor)
What is the biology of enterics?
- -Endotoxin: lipopolysaccharide (lipid A0
- -They are all catalase-positive
- -H antigen, flagella
- -K antigent, capsule or fimbriae
- -O antigen, LPS
What are the coliforms?
-Lactose positive, gram negative rods, Dark colonies on EMB agar
Where do enteric infection occur?
- - Love boat cruises, shrimp cocktail, jack in the box, uncooked hamburger
- -Most recent E. coli food! Most recent: bologna and hazelnuts.
What is E.coli?
- -Named for Escherich Germany and inhabiting the colon
- -Coliform is normal microflora of 100% of human colon and live in the intestine of all warm blooded animals
- -Special strains are highly virulent due to possession of virulence factors.
What are the diseases caused by virulent strains of E. coli?
- -Gastroenteritis: diarrheal type of diseases which are transmitted by oral-fecal routes are caused by several strains of E.coli
- -Neonatal meningitis: E. coli major cause
- -Urinary tract infection: Honey moon urthritis
What are disease caused by gastroenteritis (diarrheal) type of E.coli?
- 1. Travelers diarrhea
- 2. Infantile diarrhea
- 3. Enterohemorrhagic E. coli (EHEC)
What is travelers diarrhea?
- -Travelers to underdeveloped countries
- -Causes by enterotoxigenic strains of E. coli (ETEC) that produce a plasmid mediated heat stable toxin which causes watery diarrhea
- -Toxin stimulate hyper secretion of fluids and electrolytes from the gut epithelial cells similar to cholera toxin.
What is infantile diarrhea?
Major cause of infant death in the world (mostly underdeceloped countries)
What s enterohemorrhagic E. Coli (EHEC)
- Plasmid mediated toxin causes bloody diarrhea
- The most common strains that produce food born diease in deceloped coutries
- Toxin disrupt protein sythesis causing destruction of intestinal microvilli
- -Strain O157: H7 E coli is the major cause of food associated diarrhea disease in US
- -Hemolytic uremic syndrome (HUS): Occurs after EHEC in 5-10% of infected children younger han 10 years. Disorder characterized by hemolyic anemia and acute renal failure which may lead to loss of kidneys. Types of food at risk: Undercooked hamburger, unpasteruized milk or juice, uncooked vegetables and fruits
What is neonatal meningitis?
- -E.coli is major cause of neonatal meningitis
- -Strains that have k-1 capsule cause this
What is UTI and cystitis (bacteruira): honey moon Cystitis?
- -Infection of urethra by bacteria that reside in the colon contaminate the urethra and ascend into the bladder causing inflammation of bladder (cystitis)
- -Caused by certain strains of E.coli (uropathogenic strains) that produce extra adhesions (fimbriae or phili) that bind to cell lining of bladder
- -The infection could further ascend to kidneys (pyelonephritis)and to prostate (prostatitis)
What is the treatment of E.coli UTI?
-Need to do antibiotic sensitivity test to find the most effective drug
What is the transmission of salmonella typhi?
- -Fecal-oral, typhoid mary
- -Non- symptomatic carriage
- -Gram negative short bacillus that is motile due to its peritrichous flagella
What is typhoid fever or enteric fever?
- -salmonella typhi
- -Bacteria are ingested by food or water contaminated with feces from an infected person and they multiply in the blood stream and are absorbed into the digestive tract and eliminated with the waste
- -Symptoms: sustained fever as high as 40 (104), profuse sweating, gastroenteritis, and diarrhea, rash of flat, rose-colored spots may appear
- -In US, many from travel to other countries
- -A vaccine is available but generally reserved for people traveling to underdeveloped countries where significant exposure may occur
- -Strict attention to food and water precautions while traveling to such countries is the most effective preventive method.
What is salmonellosis?
- -Infection with different (less virulent) strains of salmonella
- -transmission: both animals and human
- -Zoonosis: foods that have come into contact with infected animal feces. Exposures happen when foods such as poultry, eggs, beef are not cooked enough. Fruit and veggies where they grow
- -human to human: Rare, poor hygiene, 10 billion organism, of feces is needed for transmission
What are the number of organisms?
- -Over 400 in two groups
- -Salmonella Enteritidis, Salmonella Typhimurium
What are the diseases, treatment, prevention of Salmonella?
- -Salmonella gastroenteritis is the most common form of salmonellosis and generally occurring after 12-72 hours incubation period
- -Disease is initiated by oral ingestion of bacteria followed by colonization of lower intestine. Bacteria are capable of mucosal invasion, which results in an acute inflammation of the cells leading to diarrhea, fever, ab cramps.
- -In most cases, lasts 3-7 days
- -Most people recover without treatment
- -US govt reported that 16.3% of children were contaminated in 2005, late 90s 20%. Late 20th century, eggs. Much less common now with the advent of hygiene measures in egg production and vaccination of hens.
What is shigella dysenteriae?
- -Food borne illness
- -Frequently found in water polluted with human feces
- -Transmitted via fecal-oral route
- -Human is only reservoir for this bacteria
- -Only a few bacteria are needed to cause infection
- -Onset time is 12-50 hours
- -Symptoms may range from mild ab discomfort to full blown (bloody diarrhea, bacillary dysentery)
- -Cramps, diarrhea, fever, vomiting, blood, pus, or mucus in stools or tenesmus
What is the epidemiology of shigella dysenteriae?
- -An estimated 18,000 cases of shigellosis occur annually in the US.
- -Day care center alert
What is the treatment of shigella dysenteria?
- -Usually self-limiting
- -Asymptomatic carriage may develop in few cases
- -Antibiotic therapy shortens the symptoms and fecal shedding.
What is vibrio cholerae?
- -Gram negative highly motile curved-rod which is present in the natural fresh and salt water reservoirs
- -Causes the disease Cholera (in humans)
- -Epidemics in Africa and South America.
What is the virulence of vibrio cholerae?
- -Once ingested, it colonizes the GI tract and adheres to microvilli of intestinal mucosa by way of its pili
- -Secretes cholera exotoxin that causes symptoms of cholera
- -Diarrhea with massive amount of fluid and electrolyte efflux (rice water stool), leads to severe dehydration.
What is the pathology of vibrio cholerae?
- -Toxin stimulate hyper secretion of fluids and electrolytes from the guy epithelial cells to the lumen of intestine
- -Severe dehydration and death due to hypovolemic shock
What is campylobacter jejuni?
- -Gram negative curved rods with motile bipolar flagella
- -#1 cause of food-borne gastroenteritis in US and world
- -The source of infection is food (raw milk, under-cooked fowl), or contract with infected animals or humans and their excreta.
- -Grow best at bird's body temp (healthy, birds may carry it)
- -Disease of all ages but in US, infants high incidence
What is the virulence factors of C. jejuni?
- LPS with endotoxic activity
- Intracellular survival
- Ability to penetrate cells
What is the pathogenesis of C. Jejuni?
- -The organism invades the epithelium of the lower small intestine and multiplies
- -Produces an inflammatory response that may be responsible for many of the symptoms
- -Start 1-10 days after ingestion with vague ab cramps that process to crampy pain, bloody diarrhea, chills, and fever for 3-6 days. Untreated patients may excrete the organism for several months
- -Erythromycin is used in severe cases
What is prevention of C. jejuni?
-Thoroughly cook poultry and use pasteurized milk only
When should you wash your hands?
- -Using the restroom
- -Handing raw food (before, after)
- -Touching hair, face, body
- -Sneezing or coughing
- -Smoking, eating, drinking
- -Handling chemicals
- -Taking out garbage or trash
- -Clearing tables
- -Touching clothing or aprons
- -Touching un-sanitized equipment, work surfaces, or wash cloths.
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