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19 Cards in this Set
- Front
- Back
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What is Yersinia species?
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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. |
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Infections of yersinia are known for severe abdominal pain, often mistaken for appendicitis. TRUE/FALSE
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TRUE.
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What is the pathogenesis of Yersinia?
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bacteria invade the small intestinal mucosa, and some enter the lymphatics and are harbored intracellularly in phagocytes. Systemic effcets are rare.
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Joint pain is rarely seen after diarrheal episodes of yersinia. TRUE/FALSE
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TRUE. This symptom resolves after several months.
Y. pseudotbc is milder than enterolitica. |
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What is the treatment for yersinia?
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Simple food hygiene should be preventitive. Antibiotics are not prescribed unless bacteremia is documented.
Doxycycline or TMP-SMZ is used. |
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What is Clostridium difficile?
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It is a Gram + endospore forming rod found as normal flora in the intestine.
It can cause a condition known as Pseudomembranous colitis. |
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What causes C. difficile colitis?
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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.
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What type of toxins does C. difficile produce/
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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. |
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Is there treatment for C. difficile?
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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. |
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Is C. difficile contagious?
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Infected persons may shed large numbers of spores in their stools, increased precautions are necessary to prevent spread.
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Are there any other treatments for C. difficile?
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Vaccination with C. difficile toxoid and restoration of normal flora by ingestion of a mixed culture of lactobacilli and yeasts.
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What is the cause of Vibrio cholerae?
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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.
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What are the cholera toxins?
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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. |
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What are the symptoms of cholera/
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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. |
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What is the pathogenesis of cholera?
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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.
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What is the virulence of cholera?
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it is due entirely to an enterotoxin called cholera toxin(CT), which disrupts the normal physiology of intestinal cells.
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Though humans easily harbor the cholera organism, it is now known that the parasite is free living in certain regions. TRUE/FALSE
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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. |
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How is cholera diagnosed?
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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.
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How is cholera prevented and trated?
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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. |
