Term
| complications and long term sequalae of enteric infections |
|
Definition
- hemolytic uremic syndrome and renal failure via Shiga toxin producing E. coli
- Guillain Barre syndrome via Campylobacter
- IBS
- chronic malnutrition
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Term
| What types of bacteria tend to cause enteric infections? Name the major causative agents of enteric infection |
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Definition
- mostly gram negative rods
- Salmonella
- Campylobacter
- Sigella
- E coli
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Term
| define acute diarrheal episode |
|
Definition
- increased frequency of defication
- less than 14 days duration
|
|
|
Term
| define persistent diarrhea |
|
Definition
- more than 14 days but less than 30 days of diarrhea
|
|
|
Term
|
Definition
- diarrhea lasting greater than 30 days
|
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Term
| function of enteric flora in host defense against enteric pathogens |
|
Definition
- mostly anaerobes
- produce toxic acidic products and volatile fatty acids
- interfere with colonization by pathogens
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Term
| modes of transmission of enteric infection |
|
Definition
- waterborne
- more so in developing countries
- foodborne (esp. in outbreaks)
- more so in industrialized
- person to person
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Term
| Outbreaks: what usually causes them? |
|
Definition
- in industrialized world, foodborne disease
- developing world, linked to environmental or social disasters (esp. with cholera)
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Term
| VF's prevelant in enteric infection |
|
Definition
- toxins
- attachment
- invassiveness
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Term
| Toxins that cause enteric infection |
|
Definition
- enterotoxin- direct effect on intestinal mucosa to elicit net fluid and electrolyte secretion
- cytotoxin- mucosal distruction
- neurotoxins (preformed and act on ANS)
- food poisoning by S. aureus, Clostridium botulinum, B. cereus
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Term
| clinical syndromes of enteric infection |
|
Definition
- food poisoning
- secretory diarrhea
- inflammatory diarrhea
- enteric fever
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Term
| Effect of C. botulinum toxin |
|
Definition
- block ACh release from motor nerves at neuromuscular junction (irreversable)
- initiates GI symptoms, progressing to paraylsis and resp. failure
|
|
|
Term
|
Definition
- injest pre-formed neurotoxins and enterotoxins
- acute onset of nausea and vomitting within 1-6 hrs followed by watery diarrhea
- symtpoms resolve within 12 hrs
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Term
| Example of causative agent of secretory diarrhea. Char. of secretory diarrhea |
|
Definition
- characteristics
- acute, non-inflam.
- enterotoxin mediated
- proximal small bowel
- watery diarrhea
- ex: cholera
|
|
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Term
|
Definition
| abrupt onset of profuse watery diarrhea with flecks of mucus (aka rice water stool) |
|
|
Term
| V. cholera: transmission and reservoir |
|
Definition
- reservoir- aquatic environments and humans
- transmission- food borne and waterborne
|
|
|
Term
| Secretory diarrhea- V. parahemolyticus: transmission and where seen most often? |
|
Definition
- seen most often on Gulf coast
- acquired from raw/undercooked shellfish
|
|
|
Term
| Enterotoxigenic (ETEC) E coli: VF and clinical syndrome |
|
Definition
- VF- enterotoxins
- heat labile toxin (basically the cholera toxin- increase cAMP)
- heat stable toxin (increase cGMP)
- both cause opening of ion channels
- clinical syndrome- watery diarrhea
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|
Term
| Primary causative agent of travelers diarrhea |
|
Definition
|
|
Term
|
Definition
- self limited (resolve 2-4 days)
- widespread resistance to amoxicillin, TMP-SMX therapy
|
|
|
Term
| Inflammatory diarrhea: causative agents, def. |
|
Definition
- def.- bloody diarrhea with fever
- causative agents
- Shigella
- STEC
- Salmonella
- C. difficile
- Campylobacter
|
|
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Term
| Shigellosis: epidemiology, VF |
|
Definition
- humans are only reservoir
- low inoculum causes disease
- transmission via fecal-oral, may be food or water born
- short incubation period (common among the enteric bugs)
- VF- Shiga toxin (AB5 structure)
- enter via receptor mediated endocytosis
- inhibit protein synthesis
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|
|
Term
| Campylobacter: epidemiology, major pathogens |
|
Definition
- epidemiology- worldwide zoonosis
- major pathogens
- C. jejuni: reservoir is poultry
- grow at 42 degrees C
- self limited illness (only GI)
- C. fetus: reservoir is cattle, sheep
- grow at 25 degrees C
- tends to disseminate
- fatal to immunocomp.
- C. enterocolitis
- complication: Guillain Barre, septic abortion, reactive arthritis
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|
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Term
| STEC E coli: epidemiology, complications |
|
Definition
- epidemiology
- associated with food and water borne outbreaks (ex: ground beef why it is called the "hamburger disease")
- complications- Hemolygic Uremic syndrome
- biggest complication- renal failure
|
|
|
Term
|
Definition
- Shiga toxin
- classic AB5 toxin
- B subunit attach to receptors on renal glomerular and tubular cells
- cytotoxic by cleaving rRNA
- STEC can produce one of two forms of the Shiga toxin
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|
Term
| nontyphoidal Salmonella transmission |
|
Definition
| contact with exotic pets, especially reptiles |
|
|
Term
| complications of nontyphoidal Salmonella enterocolitis |
|
Definition
- bacteremia with intestinal seeding
- leads to going to bones and joings
- also can cause endovascular infections
|
|
|
Term
| Treatment principles of nontyphoidal salmonella enterocolitis |
|
Definition
- antibiotic treatment can prolong carriage
- treat elderly, neonates, immunosuppressed, cardiac valve defects, prosthetic valves
- ones who could disseminate
|
|
|
Term
| What groups of people tend to be at risk for being chronic carriers of nontyphoidal Salmonella enterocolitis |
|
Definition
- elderly
- those with galstones
- infection with Schistosoma haematobium
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|
Term
| causative agents of enteric fever |
|
Definition
- Salmonella enterica servoras Typhi and paratyphi
- Yersinia
|
|
|
Term
| Hallmark of Salmonella enterica serovar Typhi and Paratyphi |
|
Definition
| prolonged fever and bacteremia |
|
|
Term
| physical exam findings and complications of typhoid fever |
|
Definition
- phy exam- rose spots are pathomneumoniic of typhoid fever (faint salmon colored rash on trunk)
- organisms cultured from biopsy of lesion
- complications- intestinal perforation/ hemorrhage
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|
Term
| diagnosis of enteric infection |
|
Definition
- stool culture for IDing bacterial organsims (golden standard)
- blood culture
- light microscopy for fecal leukocytes
- Ag detection
- toxin test (C dificile toxins A and B)
- electron microscopy (viruses)
- serology usually not useful
|
|
|
Term
| Adv. and disadv. of stool culture |
|
Definition
- disadvantages
- cost
- low yield
- special media for certain organisms
- advantages
- aids in outbreak detection and disease survailence
- rules out any other cause of diarrhea
- guides appropriate antimcrobial treatment and track resistance patterns
|
|
|
Term
| treatment principles of infectious gastroenteritis |
|
Definition
- rehydration
- nonspecific symptomatic therapy
- must report to public health
- treatment only for specific circumstances
- severe or persistent diarrhea, choice of antimicrobial governed by causative agent
- enteric fever
- certain organisms:
- C difficile
- Giardia, E. histolytica
- in some cases, antibiotics can worsen disease with some organisms
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|
Term
| prevention of enteric infection |
|
Definition
- safe drinking water in developing wourld
- Salmonella enterica serovar typhi vaccine (not that affective)
- oral: live attentuated
- injectable: heat killed
- only recommeneded for longterm travel to eares of endemic countries
- exclusive breast feeding
- child nutrition
- wash hands, safely dispose of fecdes
- give food and drink to children who are sick
- appropriate home treatment
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