Upper GI Micro Flashcards
name the two obligate anaerobe classes that are important for upper GI
clostridium
bacteriodes
name the two facultative anaerobes that are important in the upper GI
E coli
candida
what is a microaerophile? name the one that is important in the upper GI tract
helicobacter…require less O2 than atmoshpher
what does it mean to be aerotolerant? name the important one for upper GI
do not need O2 but can be in presence of it
lactobacillus
are anaerobes or aerobes more common in gut flora?
anaerobes by a ton
what are the two predominant phyla in the gut?
bacteroidetes and firmicutes
in GI infections…is it usually just anaerobe, just aerobe or a mix of both that cause the infection?
a mix of both
supragingival plaque associated biofilms are formed by what class of organisms? are they aerobes or anaerobes?
gram pos…aerobes/erotolerant
what is the common gram positive bacteria that causes supragingival plaques?
actinomyces
subgingival plaque is associated with what class of bugs?
anaerobic gram negativ
what bug is most common to cause subgingival plaque?
bacteroides
is bacteroides gram neg or pos? what shape? anaerobe or aerobe?
gram neg
anaerobe
bacilli
name the bacteroides specie that is involved with close to 80% of anaerobic GI infections
bacteroides fragilis
can bacteroides attach to epithelial cells and enter by themselves? if not how do they infect?
no…they have to use an injury to gain access
is actinomyces gram neg or pos? what shape? anaerobe or aerobe?
pos
anaerobe
bacilli
why is actinomyces confused as a fungi sometimes?
because it has branching patterns
what is actinomycosis? where does it occur on the body?
infection with actinomyces israeli…often in the jaw
what does actinomycosis occur after usually?
dental procedures
what does actinmycosis cause in the jaw that is a sign of it?
sulfur granules
is clostridium gram neg or pos? what shape? anaerobe or aerobe?
pos
anaerobe
bacilli
what are the clear ends on clostridium bacili?
endospores…for spore forming
what bacteria ferments carbs, fatty and amino acids and makes a foul smell when doing so?
clostridium
what clostridium species are associated with gas gangrene?
c perfringem and c septicum
c perfringes and c septicum are associated with gas gangrene…which of these can spread in the blood and why can it do that?
c septicum can spread because it is slightly aerotolerant
which clostridium species causes food poisoning?
c botulinum
what is an endotoxin? what is an exotoxin? what is enterotoxin?
endotoxin is LPS from gram neg membrane
exotoxin is secreted toxin from bacteria
enterotoxin is secreted toxins that target enteric cells
the toxin from c botulinum has what effect?
prevents stimulatory NTs from being released…paralysis
the toxin from c tetani has what effect?
prevent release of inhibitory NTs…spasticity
the toxin from c perfringens has what effect?
degrades tissue and cell membranes
the toxin from c difficile has what effect?
cytoxic and inflammatory effects
which organism often causes gas gangrene following surgery?
c perfringens
which organism causes spontaneous gas gangrene?
c septicum
how does spontaneous gas gangrene occur?
break in GI mucosa allows C septicum to enter bloodstream
what is present in spontaneous gas gangrene and can be seen on surface of skin
gas…gas pockets on skin
what two organisms often cause peritonitis?
E coli and B fragilis
name the three antibiotics that are always effective against anaerobes
metronidazole
carbapenems
B lactams
name the three antibiotics that are never effective against anaerobes
aminoglycosides
bactrim
aztreonam
how do we treat esophagitis caused by candida?
fluconazole
describe the steps in helicobacter pylori pathogenesis
flagella help it attach and be motile
urease converts urea to ammonia and CO2 to raise local pH
bacteria can replicate
mucinases and other effectors can damage cell and induce inflammation
what is the virulence factor that makes H pylori much more infectious?
cytotoxin associated genes
where do cytotoxin associated genes reside in H pylori? can they be transmitted between strands?
on a pathogenecity island that can jump between strands
what is the enzyme that is necessary for H pylori to live?
must have urease
with ulcers from H pylori…what two drugs do you give?
antibiotic combo plus a PPI
name the five most common H pylori test…which is most common?
serology stool antigen test urea breath test (most common) rapid urease test histology
what is the shape of H pylori? where is it seen on histo?
curved bacili
attached to epithelial cells in the GI tract
