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19 Cards in this Set

  • Front
  • Back
What is Yersinia species?
It is a genus of Gram - bacteria that includes the plague bacterium.
There are two species that cause GI tract disease.
Y. enterolitica/Y. pseudotuberculosis.
Infections of yersinia are known for severe abdominal pain, often mistaken for appendicitis. TRUE/FALSE
What is the pathogenesis of Yersinia?
bacteria invade the small intestinal mucosa, and some enter the lymphatics and are harbored intracellularly in phagocytes. Systemic effcets are rare.
Joint pain is rarely seen after diarrheal episodes of yersinia. TRUE/FALSE
TRUE. This symptom resolves after several months.
Y. pseudotbc is milder than enterolitica.
What is the treatment for yersinia?
Simple food hygiene should be preventitive. Antibiotics are not prescribed unless bacteremia is documented.
Doxycycline or TMP-SMZ is used.
What is Clostridium difficile?
It is a Gram + endospore forming rod found as normal flora in the intestine.
It can cause a condition known as Pseudomembranous colitis.
What causes C. difficile colitis?
It is also known as an antibiotic related colitis. It is also known as an antibiotic associated colitis. It is precipitated by therapy with broad spectrum antibiotics such as ampicillin/clindamycin or cephalosporins. It is a major cause of diarrhea in hospitals.
What type of toxins does C. difficile produce/
It produces two enterotoxins, toxins, A/B, that cause areas of necrosis in the wall of the intestine.
perforation of the cecum and death can result, though rarely.
Is there treatment for C. difficile?
It may respond to withdrawal of antibiotics and replacement therapy for lost fluids.
More severe infections are treated with Vancomycin or metronidazole for several weeks.
Is C. difficile contagious?
Infected persons may shed large numbers of spores in their stools, increased precautions are necessary to prevent spread.
Are there any other treatments for C. difficile?
Vaccination with C. difficile toxoid and restoration of normal flora by ingestion of a mixed culture of lactobacilli and yeasts.
What is the cause of Vibrio cholerae?
Vibrios are comma shaped rods with a single polar flagellum. Family is Vibrionacaeae. isolated specimens reveal quick darting cells that slightly resemble a cooked hot dog. They grow on ordinary or selective media.
What are the cholera toxins?
They possess O and H antigens and membrane receptor antigens that provide some basis for classifying members ogf the family.
two major biotypes are; a. Classic and b. El Tor.
What are the symptoms of cholera/
Incubation is a few hours to several days and begins with abrupt vomiting, followed by a copious secretory diarrhea.
Fluid losses of 1 litre per hour have been observed.
Acidosis from HCO3 loss and K+ depletion manifests in painful muscle cramps, thirst , flaccid skin and convulsions.
Shock, tachycardia and circulatory collapse can result in death in 55% of untreated cases.
What is the pathogenesis of cholera?
After ingestion with food or water, the acidity of the stomach can determine the needed infectious dose(10/8 cells). At the duodeno-jejunal junction, the vibrios penetrate the mucosa barrier using their flagella and adhere to epithelial cells.
What is the virulence of cholera?
it is due entirely to an enterotoxin called cholera toxin(CT), which disrupts the normal physiology of intestinal cells.
Though humans easily harbor the cholera organism, it is now known that the parasite is free living in certain regions. TRUE/FALSE
TRUE. Cold, acidic, dry environments inhibit the migration of Vibrio, whereas as warm, monsoon, alkaline and saline conditions favor them.
V. cholerae is sometimes isolated from shellfish in the Gulf of Mexico.
How is cholera diagnosed?
It is readily isolated from stool samples. Group specific antisera is supportive as well. Elusive cases can be traced by detecting a rising antitoxin titer in the serum.
How is cholera prevented and trated?
proper sewage treatment and water purification.
Vaccines are available for travelers going to endemic regions.
prompt replacement of fluids(rehydration)(ORT therapy).
severe cases, tetracycline and trimethoprim-sulfamethoxazole can terminate the diarrhea in 48 hours.