Microbiology Flashcards
difference in structure of gram positive and gram negative
unique to gram positive - lipoteichoic acid + thick peptidoglycan layer
unique to gram negative - outer membrane composed of endotoxins/LPS and porin
what bugs do not gram stain well
These Little Microbes May Unfortunately lack Real Colour But Are Everywhere
treponema pallidum, leptospira
mcobacteria
mycoplasma, ureaplasma
legionella, rickettsia, chlamydia, bartonella, anaplasma, ehrilichia
what organisms turn red or pink on gram stain
gram negatives (due to thin peptidoglycan layer)
what organisms retain violet crystal dye on gram stain
gram positive (due to thick peptidoglycan layer)
what bacteria are visualised on giemsa stain
Help! Certain Bugs Really TRY my Patients
H.pylori, chlamydia, borrelia, rickettsia, trypanosomes, plasmodium
what bacteria is visualised with periodic acid-schiff stain
tropheryma whipplei
(Whipples disease)
what bacteria are visualised on ziehl-zeilson stain
acid fast bacilli (e.g. mycobacteria)
protozoa (e.g. cryptosporidium oocytes)
what bacteria are visualised on india ink stain
cryptococcus neoformans
what bacteria are visualised on silver stain
HELiCOPters Are silver
h.pylori, legionella, bartonella henselae, fungi (coccidiodes), pneuocystitis jiroveci, aspergillus
culture media for h.influenzae
chocolate agar
culture media for n.gonorrhoea and n.meningitidis
thayer-martin agar
culture media for bordetella pertusis
bordet gengou agar
culture media for c. diptheriae
tellurite agar, loffler medium
culture media for m. tuberculosis
lowestein jensen medium
middlebrook medium, rapid automated broth cultures
culture media for m. pneumoniae
eaton agar - requires cholesterol
culture media for lactose fermenting enterics
Maccokey agar - turns pink
culture media for e.coli
Wosin-methylene blue (EMB) agar
culture media for brucella, francisella, legionella, pasteurella
charcoal yeast extract agar buffered with cysteine and iron
culture media for fungi
sabouraud agar
(sab’s a fun guy)
why are aminoglycosides ineffective at treating anaerobes
aminoglycosides require oxygen to enter into bacteria cell
what are the anaerobes
anaerobes Cant Breath Fresh Air
clostridium
bacteroides
fusobacterium
actinomyces
obligate intracellular bacteria examples
stay inside (cells) when its Really Chilly and Cold
Ricketssia
Chlamydia
Coxiella
facultative intracellular bacteria examples
Some Nasty Bugs May Liver facultativeLY
Salmonella
Neissiseria
Brucella
Mycobacterium
Listeria
Fancisella
Legionella
Yersinia pestis
people without a spleen are at risk of what type of infections and why
infections by encapsulated bacteria
encapsulated bacteria are optomised and then cleared by the spleen. Without a spleen they are not optomized and thus increased risk for severe infections
Please SHiNE my SKiS
psueodomonas
H.influenzae
N.meningitidis
Salmonella
klebsiella
group B Strep
asplenic patients require what additional vaccines
vaccines against encapsulated bacteria;
h.influenzae
n. meningitidis
strep pneumoniae
urease positive organisms
Pee CHUNKS
proteus
cryptococcus
h. pylori
ureaplasma
nocardia
klebsiella
s. epidermidis
s. saprophyticus
urease positive organisms predisposes to what type of renal stones
struvite (magnesium ammonium phosphate)
golden yellow pigment producing bacteria
staph aureus (aureus in latin = gold)
blue-green pigment producing bacteria
pseudomonas (aerugula is green)
red pigment producing bacteria
serratia marcescens (red srirachia sauce)
yellow ‘sulphur’ granules producing bacteria
actinomyces israelii
(israel has yellow sand)
bacterial virulence factor - protein A binds Fc region of IgG preventing optomization and phagocytosis
staph aureus
bacterial virulence factor - IgA protease cleaves IgA allowing bacteria to adhere to and colonize mucous membranes
strep pneumoniae, h.influenzae and Neisseeria
inactivation elongation factor (EF-2) through ADP ribosylation
corynebacterium diptheriae
pseudomonas
inactivates 60S ribosome by removing adenosine from rRNA
enterohaemorrhagi E.coli
shigella spp.
mimics andeylate cyclase (increases cAMP)
anthrax tocin (bacillus anthracis)
overactivates adenlylate cyclase (increases cAMP) by permenantly activating Gs
cholera toxin (vibro cholerae)
responsible bacteria for ‘rice water’ diarrhoea and mechanism of action
vibro cholerae
overstimulates adenylate cyclase (increases cAMP) by permanantly activating Gs
activates adenylate cyclase by inactivating inhibitory subunit Gi
pertusis
proteases that cleave SNARE (soluble NSF attachment protein receptor), a set of proteins required for neurotransmitter release via vesicular fusion
clostridium botulimun - botulin toxin
clostridium tetani - tetanospasmin toxin
phospholipase that degrades tissue and cell membranes
clostridium perfringes - alpha toxin
protein that degrades cell membrane
strep pyogenes - streptolysin O
cross linking beta region of TCR to MHC class II on APCs outside of the antigen binding site –> overwhelming release of IL1, IL2, IFN-Y and TNF alpha = shock
staph aureus - toxic shock toxin (TSST-1)
strep pyogenes - erythrogenic exotoxin A
gram positive cocci, catalase positive, coagulase positive bacterium
staph aureus
gram positive cocci, catalase negative, beta haemolytic
bacitracin sensitivity and PYR status;
positive - group A strep pyogenes
negative - group B strep agalactiae
gram positive cocci, catalase negative, alpha haemolytic
optochin sensitivity and bile solubility;
positive - strep pneumoniae
negative - strep viridians
gram positive cocci, catalase negative, gamma haemolytic
positive - enterococcus
negative - strep gallolyticus
gram positive cocci, catalase positive, coagulase negative, urease positive in clusters
staph epidermidis + staph saprophyticus
gram positive cocci, catalase negative, alpha haemolytic, optochin positive, lancet-shaped diplococci
strep pneumoniae
gram positive cocci, catalase negative, alpha haemolytic, optochin negative
viridians (strep mutans, strep mitis)
gram positive cocci, catalase positive, coagulase negative, novobiocin positive
staph epidermidis
gram negative diplocci non-maltose fermenting
N.gonorrhoea
gram negative diplococci maltose fermenting
N. meningitidis
gram negative cocobacillus
h.influenzae
bordetella pertusis
rickettsia rickettsi
gram negative lactose fermenting fast bacillus
e.coli
klebsiella
gram negative lactose fermenting slow bacillus
serratia
citrobacter
gram negative curved rods oxidase positive
campylobacter, cholerae, h.pylori
why is there not a vaccine for gonorrhoea
due to antigenic variation of pilus protein
treatment brucella
doxycycline + rifampicin/streptomycin
how do salmonella and shigella invade the GI tract
through M cells of payers patches
describe the presentation of rocky mountain spotty fever
rash starts on palms and soles of feet then spreads
rash, fever, headache
rocky mountain spotty fever bacterium and vector
rickettsia rickettsi
intracellular gram negative diplococci
vector = tick
occurs in south atlantic states esp North carolina
genomic structure of EBV
part of herpesviridae
double stranded linear DNA
blocks release of glycine and GABA
clostridium tetani
how does clostridium tetani spread
tetanospasmin remains localised to wound site
tetanospasmin spreads by retrograde axonal transport to CNS
ingestion of honey can put a baby at risk of what infection
clostridium botulism
virulence factor for E.coli infections causing cystitis and pyelonphritis infections
fimbrae
virulence factor for e.coli infections causing pneumonia and neonatal meningitis infections
K capsule
virulence factor for e.coli infections causing septic shock
LPS endotoxin
produces alpha toxin which causes myonecrosis
clostridium perfringes = gas gangrene (skin creptius)
gram positive, forms long branching filaments resembling fungi
nocardia + actinomyces
in what cells does CMV acquire latency
monocytes
