Glossary of Chapter 9: The Enterics 2
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- What are the main groups of enteric bugs?
- Enterobacteriaceae, Vibrionaceae, Pseudomonadaceae, and Bacteroidaceae
- Which enterics DON'T ferment lactose?
- Salmonella, Shigella, and Pseudomonas
- Describe three levels of intestinal invasion causing diarrhea?
- 1. no cell invasion, diarrhea is caused by exotoxin-mediated fluid loss.
2. Invasion of the intestinal epithelial cells - systemic immune response with WBC infiltration and RBC leakage into the stool.
3. Invasion of the lymph nodes and bloodstream - diarrhea and systemic symptoms
- What are the diseases caused by E. coli?
- 1. Diarrhea
3. Neonatal meningitis
4. Gram (-) sepsis, commonly in debilitated patients
- What are the three groups of diarrhea-producing E.coli?
- 1. Enterotoxigenic E.coli (ETEC)
2. Enterohemorrhagic E.coli (EHEC), including E.coli 0157:H7 which causes HUS
3. Enteroinvasive E.coli (EIEC)
- Describe the diarrhea caused by ETEC?
- Heat stabile and heat labile toxins are like cholera exotoxins - severe watery diarrhea, stool looks like rice water
- Describe the diarrhea caused by EHEC?
- Shiga-like toxin causes bloody diarrhea
- Describe the diarrhea caused by EIEC?
- Bloody with WBCs, like shigellosis. Also causes fever.
- How can E.coli travel up the urethra?
- Acquisition of a pili virulence factor.
- What are the three leading causes of neonatal meningitis?
- Group B strep, E.coli, and Listeria.
- What is the most common cause of gram (-) sepsis?
- What is Klebsiella pneumonia?
- Encapsulated, nonmotile bug, causing sepsis, UTI, and pneumonia, characterized by a red currant jelly sputum.
- Why is Proteus useful for lab tests?
- Cross-reacting antigens with some Rickettsia serves as a clinical tool for determining whether someone has been infected with Rickettsia.
- Describe characteristic of Shigella. Contrast with E.coli.
- Nonmotile, does not ferment lactose and does not produce H2S. Humans are the only host - and Shigella is always a pathogen.
- What illness does Shigella cause?
- Begins with fever, abdominal pain, and diarrhea, which may contain blood and pus.
- Describe characteristics of Salmonella?
- Non-lactose fermenter, is motile, and produces H2S.
- What are the three clinically significant groups of Salmonella?
- S. typhi, S. cholerae-suis, and S. enteritidis
- Salmonella causes which 4 disease states in humans?
- Typhoid fever, carrier state, sepsis, and gastroenteritis
- Describe clinical features of typhoid fever?
- Fever, headache, and abd. pain that is often localized to the right lower quadrant. Diarrhea may develop, spleen may enlarge, and rose spots may appear on the abdomen.
- What is appropriate therapy for Salmonella typhi?
- Ciprofloxacin or ceftriaxone
- Salmonella sepsis is usually caused by which bug? Which organs does it primarily infect?
- Salmonella choleraesuis. Infects lungs, brain, or bone.
- Why are sickle-cell patients particularly prone to Salmonella osteomyelitis and other infections?
- Their asplenic state makes it difficult to clear these encapsulated bacteria. (Normally, macrophages and neutrophils in the spleen phagocytose opsonized bacteria)
- Salmonella diarrhea is usually caused by…? Treatment?
- Salmonella enteritidis. Treatment involves fluid and electrolyte replacement.
- What is Yersinia enterocolitica? Causes pain where?
- Motile gram-negative rod, transferred by the fecal-oral route. Pain in the right lower quadrant of the abdomen.
- What is Yersinia enterocolitica’s unique survival feature?
- Can survive and grow in the cold.
- Vibrio cholera shape?
- Curved gram-negative rod with a single polar flagellum.
- V. cholera causes a similar (though more severe) disease as which E.coli subtype? Produces what kind of diarrhea?
- ETEC. Watery (rice water) diarrhea.
- What are the three most common causes of diarrhea in the world?
- Campylobacter jejuni, ETEC, and the Rotavirus.
- Campylobacter jejuni causes which type of diarrhea?
- Bloody, loose diarrhea.
- What is the most common cause of duodenal ulcers? Gastric ulcers?
- Helicobacter pylori. Aspirin products.
- Describe Pseudomonas aeruginosa? Shape, gram, scent, invasive ability, toxins?
- Obligate aerobic gram (-) rod. Produces grape-like scent. Weak invasive ability. Exotoxin A, similar mechanism as diphtheria toxin.
- List the important Pseudomonas infections?
- 1. Pneumonia
3. Burn-wound infections
5. UTIs, pyelonephritis
7. Malignant external otitis
8. Corneal infections
- Which patients are at-risk for Pseudomonas pneumonia?
- CF patients and immunocompromised patients.
- Which patients are at risk for Pseudomonas osteomyelitis?
- Diabetics, IV drug abusers, children with puncture wounds to the foot.
- What is the general treatment regimen for Pseudomonas?
- Anti-pseudomonal penicillin combined with an aminoglycoside for synergy
- When do we encounter Bacteroides fragilis infections?
- Bullet wounds through the intestine, seat belt lacerations in MVA’s, bowel penetration in abdominal surgery, etc.
- Following abdominal surgery, which antibiotics that cover anaerobes are given as prophylaxis?
- Clindamycin, metronidazole, chloramphenicol, etc.
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