Glossary of Micro: Enteric Bacteria
Other Decks By This User
- Which diarrheal diseases are primarliy toxin mediated?
- Enterotoxigenic E. Coli: Symptoms
- watery diarrhea, nausea, abdominal cramps, low grade fever
travelers diarrhea and infantile diarrhea
- Describe the virulence of ETEC?
- Enterotoxin (Cholera like)
LT: heat labile; similar to cholera toxin but milder
ST: heat stabile; causes increase in cGMP
has fimbriae and CFAs for colonization in the Small Intestine
- ETEC: What common disease does it cause?
- Traveller's diarrhea
- Enteroinvasive E. Coli(EIEC): Describe its mode of infection and symptoms.
- INVASION of Large intestine epithelium similar to Shigella
causes dysentery w/ fever, abd. cramping, blood and pus in stool
- Enteropathogenic E. Coli: What common disease state does it cause?
- Infant diarrhea
- EPEC: Describe its mode of pathogenecity?
- ADHERENCE to enterocytes (Small intestine)
effacement of microvilli
expresses intimin- mediates entry in to cell
bundle forming pilli for attachment
- EPEC: Describe pathogenesis
- ADHERENCE to sm. intestine enterocytes
EFFACEMENT of microvilli
*inflammatory response may cause ulceration
- What strain of EHEC causes disease?
Where is it typically found?
- the O157:H7 serotype
it is found in cattle, beef products, and fruit and veggies that have been fertilized with tainted manure
- What characteristic differentiates EHEC from other strains of E. coli?
- Its inability to ferment sorbitol.
- Describe the symptoms caused by EHEC.
What is its primary pathogenic mehcanism?
- hemorrhagic colitis, bloody diarrhea, abd. cramping
HUS - possibly because of specific LPS
- What is the pathogenic mechanism of EHEC?
- Shiga like TOXIN
Attachment and Effacing of microvilli leading to their death
- Yersinia enterocolitica: clinical presentations?
- enterocolitis involving fever, diarrhea, and abdominal pain
nonenteric lymphadenitis may lead to septicemia
- Yersinia enterocolitica: pathogenesis?
- INVASION of M cells in small intestine
secretion of a toxin similar to E. Coli Heat stable toxin
* resevior is farm animals
- T/F: S. typhii has no animal reservoir while S. enteritidis does.
- How is E. Coli Diagnosed and treated?
- detection is difficult, some labs may serotype
treated with fluid replacement, antibiotics
EHEC strains grow on Sorbitol agar
- What are the steps involved in the pathogenesis of S. typhii?
- *binds M cells of GI epithelia *endocytosed and transferred to Peyer's patch *replicates intracellularly *passes through basal lamina *taken up by macrophage and spread thru RES
- A chronic carrier state is possible with S. typhii. What organ is notorious for sequestering the bacteria?
- Gall bladder
- EAEC: what is its primary pathogenic mechanism?
- ADHERENCE to enterocytes
Heat stabile toxin called EAST that eleveates cGMP
attaching and effacing lesions
- What are general characteristics of Enterobacteriaceae?
- Gram(-) bacteria that are part of the normal intestinal flora
non spore formers
- What are the 4 genus' of enterics?
- enterobacteriaceae, vibrionaceae, pseudomonadaceae, bacteroidaceae
- Vibrio Cholera: clinical manifestations?
- Classic "rice water" stool diarrhea w/ high fluid output
infxn may be asymptomatic, cause mild diarrhea, or result in a carrier state
- Vibrio Cholera: pathogenesis?
- polar flagellum (H-ag) - motility
*mucinase to digest mucous layers
- Describe the Cholera toxin?
- two A subunits bridged by disulfide bonds and 5 identical B subunits
A1 is active subunits-enters cell upregulates adenyl cyclase --> increased cAMP leading to cause massive efflux of Na= and H20
*regulon family of genes
- Vibrio Cholera: Diagnosis?
- darkfeild microscope
isolation on thiosulfate-citrate-bile-sucrose(TCBS) agar
agglutination in specific antisera
- Vibrio Cholera: Rx?
- Rehydration orally
- Vibrio Cholera: Immunity?
- post infection Abs
vaccines are KILLED WHOLE CELLS
- Vibrio parahemolyticus
- marine org, infects shellfish
major cause of FP in Japan and in US from eating raw shellfish
explosive diarrhea (w/o blood or mucous), cramps, nausea, vomiting
*produces a toxin
- Vibrio vulnificus
- found in salt h2o, infects sun bathers and those ingesting raw shellfish
can cause a fatal bacteremia
immunocompromised, liver diseased and thalassemia increase risk
- Campylobacter jejuni: transmission?
- transmitted by contaminated milk, H20, poultry
- Camplylobacter jejuni: clinical manifestations?
- bloody, pus-filled diarrhea, severe ab pain, fever
high pediatric incidence
no1 cause of gastroenteritis in developed world
*assoc. w/Guillan-Barre syndrome
- Camplylobacter jejuni: bacterial characteristics?
- G- curved rod
- Helicobacter pylori: clinical manisfestations?
- cause of gastritis, PEPTIC and DUODENAL ULCERS
makes a urease theat produces NH3 from urea
cured with Antibiotics
- Shigella species: clinical manifestations?
- shigellosis- fever, chills, abdominal cramps, tenesmus
blood/ pus/ mucous in stool
can cause convulsions and meningitis in infants
S. dysenteriae cause most severe infections; S.sonnei and S.flexneri most common in US
- Shigella species: transmission?
- man is primary host
P to P: fecal-oral transmission or by vectors(food, fingers, feces, flies)
associated w/ overcrowding and poor sanitation
- Shigella species: Pathogenesis?
- invades/ damages mucosa of large intestine, ulceration, and appearance of PMNS --> scarring
invasion genes are on plasmid, involves actin polymerization
Shiga toxin, INVASION
- Shigella species: Describe the Shiga toxin?
- A+B toxin (similar to Cholera)
inhibits protein synthesis by inactivating the 60s ribosome
also behaves as neurotoxin
*not essential for virulence
- Shigella species: diagnosis?
- rectal swab
*Shigella IS NOT Normal Flora
- Shigella species: Rx and immunity?
antibiotic resistance emerging
previous infection only gives short lived immunity, no vaccine
- Salmonella gastroenteritis: clinical manifestations?
- diarrhea, fever, cramping, nausea, vomiting, headache
onset 24-48 hrs after ingestion
diarrhea has rotten egg smell
blood stream invasion may occur, but disease is usually self limiting
- Salmonella gastroenteritis: organisms
- S.typhi --> typhoid fever
S.typhimurium - most common causitive org in US
- What are the 3 clinical sydromes that can result from infection with Salmonella species?
- 1. enteric fever
2. septicemic syndrome
- Salmonella gastroenteritis: transmission?
- fecal-oral route
chicken, raw eggs, mayonaise
unpasteurized OJ, apple cider
- Salmonella gastroenteritis: pathogenesis?
- attachment and invasion of mucosal (M cells) of SMALL INTESTINE, damages tissue
may produce a toxin but not major virulence factor
- Salmonella gastroenteritis: diagnosis?
- fecal culture on selctive/differential agar (Salm are lac-)
slide agglutination for serogroups
- Salmonella gastroenteritis: Rx and immunity?
- flouroquinolones (ciprofloxacin)
- Enteric Fevers: causitive agents?
- S. typhi - typhoid fever, Vi antigen (capsular polysacchride)
S. paratyphi and S.schotmulleri cause milder fevers
- Enteric Fevers: clinical manifestations?
- intially malaise, headache, anorexia
wk1: gradual stepwise rise in fever, constipation or diarrhea
wk2: rose spots, hi fever, septecemia
wk3: fever remits, may have ulceration and gut perforation --> bloody diarrhea
- Enteric Fevers: pathogenesis?
- ingested and multiply in small intestine
penetrate mucosa at distal end ileum through M cells at Peyers Patches, move through blood stream --> bacteremia
infection of gall bladder can lead to chronic carrier state or reinfection
- Enteric Fevers: Transmission?
- S.typhi only infects humans by direct contact or ingesting food contaminated by orgs shed by carrier (Typhoid Mary)
- Enteric Fevers: Diagnosis?
- isolation of org on agar or serotyping
blood is positive in wk1 of infection
stool is positive after wk1
- Enteric Fevers: Rx and immunity?
- Short course, fluoroquinolones
Abs protects, infection stimulates cellular immunity
Vaccines: killed whole cells, live attenuated, IV injected capsular polysacchride
- Septicemic Syndrome: organism and clinical manifestations?
- S. cholraesuis
causing spiking fevers w/ frequent seeding to various organs --> abscesses, meningitis, pneumonia, osteomyelitis, endocarditis
- General characteristics of Enteric Bacteria
- Gram - bacilli
You must Login or Register to add cards