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Micro Final:Slide 22: Infections of the Digestive System

Terms in this set (85)

Overview: is a slow-growing, microaerophilic,
curved or spiral gram negative rod.
Discovered recently (1982) by an Australian physician, Dr. Marshall. He was unable to convince the scientific
community that there were curve-shaped bacteria in the stomachs of patients with ulcers. To prove his point he drank H. pylori and his stomach became colonized by the bacteria, and he developed gastritis. He treated himself with antibiotics to cure the gastritis.
Transmission: Best explanation appears to be Gastro-Oral
Gastro-Oral is ingestion of vomit.
H. pylori can be isolated in the air and vomit
Higher incidence in older adults likely represents a higher infection rate as children, not of adult acquisition.
Virulence Factors: Flagella, Urease.
Disease: H. pylori has now been shown to be responsible for >95%
of peptic ulcers, and 100% of chronic gastritis. It is thought that it is
also a cause of stomach cancer, as most stomach cancer is
preceeded by gastritis and ulcers.
Gastritis - Chronic lifelong inflammation of the stomach wall. May be
minor to severe.
Ulcers -
Gastric Ulcers - low acid, pan gastritis, high cancer risk
Duodenal Ulcers - high acid, antral gastritis, low cancer risk
How or why ulcers develop, and one form versus the other form is not clear
at this time.
Symptoms: Heartburn, abdominal pain, to severe abdominal pain,
guarding, rebound tenderness and shock
Weight loss and anemia
Chronic morning sickness during pregnancy has been suggested in
one study to be highly correlated with H. pylori status.
Vaccine: none
Treatment: Triple and quadruple antibiotic regimens.
Case 5
Homeless elderly lady presents with a fractured hip
at the ER.
Chest infection - treated with a cephalosporin - for 1
week
Hmmm? Which one? Some of these kill EVERYTHING
some are not so bad.
Develops profuse watery diarrhea and abdominal
pain.
Vaccine: none
Treatment: Triple and quadruple antibiotic regimens
Overview: Gram positive coccus, anaerobic spore former. Toxin mediated disease.
C. difficile is carried in 3% of adults, and in 15-20% of antibiotic recipients. Interestingly, as many as 50-75% of neonates may become colonized as a nosocomial infection, though most remain asymptomatic.
Transmission: Fecal-oral. Nosocomial. Aerosol transmission has been demonstrated in barns. NORMAL FLORA - transmission may not be necessary.
ENVIRONMENTAL SURVIVAL - It forms endospores and is able to survive in the external environment. It is completely resistant to hand sanitizer and most common disinfectants.
Epidemiology USA - ???
2011 - "nearly half a million" and 29,000 dead in <30 days
2013 - "minimum" of 250,000 and 14,000 deaths
Top 30 List - Infectious Deaths Worldwide 2010
Disease: C. difficile is the major organism associated
with antibiotic-associated diarrhea and
pseudomembranous colitis. May develop toxic
megacolon.
Diarrhea often results when growth of the normal flora has been disrupted by antibiotics. Particularly
common after treatment with clindamycin or penicillins.
Symptoms are explosive, sometimes bloody diarrhea.
Disease can be fatal.
Treatment
Mild disease - discontinue antibiotics.
Severe diarrhea - discontinue antibiotics and treat with
Vancomycin for 14 days or
Metronidazole for 14 days
Management
High rate of relapse is seen (10-30%)
In some studies about half that relapse is reinfection
Retreatment is often attempted, relapse rate is 64%. The patients that relapse are difficult to manage. Fecal enemas may be used to restore normal flora.
Traditional hand washing with soap and water would be recommended during an outbreak or in working with a patient who is infected.
Overview:
Enveloped +RNA virus, Flaviviridae family (Hep C, Dengue, Yellow Fever).
Transmission: Hepatitis C (HCV) generally is transmitted through blood (IV drug users, transfusions, etc.), but can also be transmitted inefficiently through sexual activity (traumatic sex - requires blood transmission) - especially common in IV drug users and anal sex.
Transmission rates between monogomous partners is
generally very low unless they share razors, toothbrushes or otherwise facilitate blood transmission. There is only a 5% lifetime risk of transmission in monogamous partners.
There is a 7% risk of transmission to the fetus.
There is some risk from hemodialysis.
Epidemiology: Seroprevalence is 1.8%. About 20,000
new infections occur annually. 10,000 to 20,000 deaths
per year.
Disease:
1. 15% acute hepatitis with resolution (4-6 months)
2. 70% chronic persistent carriers (lifelong)
3. 15% severe rapid progression cirrhosis
There are few symptoms with primary infection, about 20-50% fully recover. 50-80% of acute infections with HCV develop into a symptomless chronic infection.
20% of chronic patients have liver cirrhosis, and of these 20% suffer liver failure. The rate of progression is much higher in alcoholics.
HCV is the most common reason for liver transplant.
There are 2-4 million chronic carriers in the USA.
Vaccine: none
Treatment: Not using alcohol, Tylenol or other liver
damaging agents.
2013 - Solvadi - $84,000 for 12 weeks, 90% success
2014 - Viekira Pak - $83,500 for 24 weeks
3.3% of prescription drug dollars in USA in 4th quarter 2013.