Glossary of Lecture 1 2
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- Every member of the family Enterobacteriaceae is:
- -Gram neg bacillus
-Ferments glucose w or w/out gas
-Reduces nitrate to nitrite
-If it's motile, it's peritrichous
- enterobacteriaceae are normal flora in
- the intestinal tract; they help us to digest our food
- What is endotoxin composed of?
- what is the #1 cause of gram negative shock/sepsis
- escherichia coli
- symptoms of gnshock
- high fever, shaking chills, lowered blood pressure, peripheral circulatory failure, confusion, rapid death without treatment
- what antibiotics would we not even test enterobacteriaceae for, and why?
Enterobacter. always restist these! They're really for gram positives.
- Nonpathogenic enterobacs group 1:ABC
kleb, ecoli, serratia, citrobacter
providencia, enterobacter, morganella, proteus
- If the non-pathogenic bacteria DO cause an infection, what five could it be one of?
- UTI: most common it would be
Pneumonia: mostly from klebsiella
Wound Infections: from self/others
Sepsis: spread from 1' site to blood
Neonatal Meningitis: from e.coli in the birth canal
- the most effective group of antibiotics for the enterobacteriaceae are:
piperacillin, ampicillin, nitrofurantoin, gentamicin/tobramycin, carbenicillin
- 5 genuses of enteric pathogens:
- how many species of shigella
what are they
- most encountered species of shigella:
- least encountered shigella
- Shigellosis is aka
- bacillary dysentery
- difference between diahrrea and dysentery:
- water vs diahrrea with blood and mucous
-mechanism of disease
-incubation time before symptoms
- Anal to oral; through bad hygiene/food.
Necrosis; bugs invade cells of colon.
3 days (36-72 hrs)
Staph only takes 2-6!
- How is shigellosis treated?
- It's selflimiting after 3-7 days, otherwise use trimethoprim sulfamethoxazole (SXT) if necessary
- Most common symptom of Edwardsiella tarda; in whom?
- Diahhrea in fishtank cleaners
- what are the natural resorvoirs of edwardsiella tarda?
- fish and reptiles
- what is the most frequently encountered pathogen?
- 2 diseases of salmonella
- what two bugs cause enterocolitis?
- Salmonella enteritidis (most often)
Salmonella typhimurium (2nd often)
- what is antoher name for enterocolitis?
- incubation time for salmonellosis
- 8-24 hrs
- Compare the disease mechanisms of Salmonella and Shigella
- Shigella causes necrosis of colon cells
Salmonella doesn't; it does invade them though.
- symptoms of salmonellosis
- -Severe abdominal pain
- what organism causes typhoid fever?
how is it transmitted?
- Salmonella typhi
Bad hygiene, contaminated food/h2o from a carrier
- symptoms of typhoid fever
- febrile disease: fever, headache, lethargy, cough, splenomegaly, hepatomegaly, rash, slight diarrhea.
- how is typhoid fever treated
- sulfamethoxazole trimethoprim SXT
- What does Yersinia enterocolitica cause
- what 3 organisms (not one genus) cause enterocolitis?
- Salmonella typhimurium,
- How is Y. enterocolitica carried and transmitted?
- Carried in Intest. tracts of wild/domestic animals.
transmitted by ingestion of contaminated food/water
- Symptoms of enterocolitis from y. enterocolitica:
- abdominal pain and diarrhea
- Growth requirements of Y. enterocolitica
- -does not grow well on enteric media;
-requires CIN media
contains Cefsulodin, irgasan, and novobiocin.
- two types of E.coli variations based on the diseases they cause
- Enteropathogenic - causes dysentery
Uncommon in U.S.
Enterotoxigenic - causes Mexican diarrh.
- What is the most typical e. coli strain we see as cause of disease?
- E. coli 0157:H7
grows on SMAC - sorbital MAC agar;
Causes Hemolytic Uremic syndrome
- What organism caused bubonic plague
- yersinia pestis
- What organism causes mesenteric lymphadenopathy?
common or rare
- Yersinia pseudotuberculosis; symptoms are similar to appendicitis.
- Pathogenic characteristics of Y. pestis
- Zoonotic disease transmitted by rodent bites;
Oxidase neg (where Pasteurella is +)
Most common form is BUBONIC because of VERY LARGE inguinal or axillar lymphadenopathy.
Uncontagious as bubonic, but pneumonic IS contagious
- factor that makes S. typhi especially pathogenic
- can be transmitted from carriers - the organism is lodged in the gallbladder but it's asymptomatic
- another name for Hemorrhagic E. coli:
- how is hemorrhagic e. coli transmitted?
what is the general resorvoir
- -undercooked beef
- Symptoms of hemorrhagic e. coli infection:
- severe cramps
- culture media requirements of E.coli 0157:h7:
- SMAC - sorbital MAC --> allows differentiation of Hemorrhagic ecoli from others.
CT-SMAC: cefixine/tellurite + SMAC -> inhibits growth of other ecoli bugs
- What is the difference btwn SMAC and MAC?
- SMAC has sorbitol;
pH indic: phenol red
normal e.coli ferment sorbitol and turn pink; hemorrhagic does not, so remains clear.
- what population is Hemolytic Uremic syndrome usually seen in?
what is the mechanism of the disease?
- elderly/young chidren
causes blood clots in kidneys, RBC lysis, renal failure.
- Why is hemolytic uremic syndrome (HUS) difficult to treat?
- Treating with antibiotics inhibits normal flora and enables the pathogenic 0157-H7 to grow even better!
- how are enteric pathogens differentiated?
- 1. screening specimens for enteric bugs
2. biochemical id
3. serological typing
- 3 antigen types on enterobacteria:
- O -> Somatic
H -> Flagella
K -> envelope (capsular)
- process of Otyping for salmonella:
- 1. Apply PolyO antibody (against all 50 types of O)
If no agglutination: either not salmonella, or the H/K ag are masking O
2. Boil to destroy H/K antigens (heat labile)
3. Retest with PolyO; if agglutination:
4. Test with individual anti-sera ->most common is Anti-D, Anti-A,C
5. Subtype -> then do H serotype
- what is PFGE essentially?
- pulsed field gel electrophoresis;
fingerprint-typing to match enteric bacterial strains that are same in various patients.
- What bacteria are not serotyped?
- what do we know from positive fermentors on enteric agar?
- fermentation indicates normal flora
nonfermentors are POSSIBLE pathogens
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