micro Flashcards by Christina Taplin

transpeptidase

peptidoglycan synthesis

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methicilin

effective against pen G resistant staph aureus

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glycopeptides mech of action

binds to terminal D-ala D-ala and prevents cell wall synthesis

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eg of a glycopeptide

vancomycin

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aminoglycosides mech of action

bind to ribosome and distort reading frame, abnormal protein production, cell wall weakens, increased entry and total ribosome blockade

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eg of an aminoglycoside

gentamicin

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metronidazole

to kill anaerobes - need nitroreductase to activate

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3 things resistant to vancomycin

gram neg
resistant enterococci
vancomycin intermediate SA

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mech of action vancomycin intermediate SA

produces extra peptidoglycan

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resistnat enterococci mech of action

replaces D-ala with D-lac

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mech of action methicillin resistant SA

produces altered penicillin binding proteins/transpeptidases

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what do you use doxyclcine for

mycoplasma

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what is bacterial lag phase

when grow before binary fission

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facultative anaerobes

grow w or w/out O

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how does yersinia enter cells

binds to integrins on M cell surface and induces phagocytosis

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pyogenic pathogen

pathogen that evades phagocytosis

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facultative intracellular pathogen

pathogen that resists killing inside clel

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where does TB live

inside macs

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strategies to evade phagocytosis

produce leukocidins - kill WBCs
surface anti-phagocytic structures
interfere with opsonins

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what is a capsule made out of

polysaccharide

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what is adult and child pneumococcal vaccine

adult - 23 valent polysaccharide vaccine

children - 13 valent conjugated

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why do capsules enhance virulence

either

resemble host components - strep pyogenes
mask underlying structures e.g. LPS - so complement cant bind via alt pathway

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how does IgM and IgG cause phagocytosis

IgM fixes complement C3b - phagocytes have C3bRs

IgG R for heavy chain on phagocytes

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difference between endo and exotoxin

endotoxin - LPS - released as cell dying, heat resistant, causes fever, non-specific

exotoxin - active secretion of protein from multiplying bacteria, high antigenicity, highly specific

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eg of a cytotoxic exotoxin

shiga toxin, diptheria

eg of a cytotonic endotoxin

cholera, hs enterotoxin

structure of shiga toxin, what type of toxin is it

B (binding) and A (enzymatically active) subunits | intracellular cytotoxic exotoxin

what can you make toxoid out of

exotoxin (NOT ENDOTOXIN)

what are super antigens

bind directly to MHCII and recognised by lots of T cells

what does binding of PAMP to PRR on DC cause

increased MHCI and II increased CD80/86 decreased adhesion molecules migrate to lymph node

what do Th1 cells produce

IFNgamma and TNF

what is ab dependent cell mediated cytotoxicity

IgG binds, NK cell has FceRs recognises Fc portion of Abs, binds releases IFNgamma and perforin and causes lysis

structure of tetracyclins

4 membered ring structure

penicillin V

oral :)

ampicillin

kills cocci and rods

methicillin

to treat penicillin resistant staph aureus

amoxycillin

basically = ampicillin

what is vancomycin

glycopeptide - works on cell wall

what is e.g. of aminoglycoside

gentamicin

mech of action of vancomycin

glycopeptide - binds to terminal D-ala D-ala so can't cross-link - terminates wall synthesis

how is enterococci resistant to vancomycin

replaces terminal D-ala with D-lac, has new transpeptidases that can use D-lac as precursor

VISA

vancomycin intermediate staph aureus | produces extra peptidoglycan acts as sink to soak up vanco, and can't administer more bc vanco toxic

how do B-lactams work

AB looks like D-ala D-ala so transpeptidases bind penicillin instead and disrupts cell wall synthesis

MRSA

methicillin resistant staph aureus - makes low affinity penicillin binding proteins

what is intrinsically resistant to vancomycin

all GN

what makes pseudomonas aeruginosa scary

intrinsically produces B-lactamase

what does pathogen need to be killed by metronidazole

nitroreductase - strict anaerobes

how is enterococci resistant to sulfonamides

doesn't synthesis folic acid

why we worried about enterococci

bc resistant to things and likes passing around its genes

requirements for gene transfer via transformation

methylated in particular way so not cut by restriction enzymes similar enough for homologous recombination into DNA

what is MIC test of

bacteriostatic capacity

what is a B-lactamase inhibitor

clavulanate

cause of pharyngitis w/out nose

strep pyogenes

cause of pharyngitis w nose

adenovirus

cuase of cold

rhinovirus

cause of ottitis media

pneumococci

cause of epiglottitis

H influenzae type B

cause of croup/LTB

parainfluenza

when would you treat an URTI

otitis media if <2yrs old, epiglottitis MUST

cause of acute bronchitis

viral

cause of acute exacerbation of chronic bronchitis

pneumococci

cause of bronchiolotis

RSV

cause of empyma

staph aureus

what is empyma

pus in pleural cavity

what are some reasons for getting pneumonia

1. defect in host defences 2. highly virulent microbe 3. infective dose large

how do you treat pneumonia

penG/amoxycillin and doxycycline

agents of UTI

Ecoli, staph saprophyticus, proteus species

virulence factor that allows infection of bladder and pathogen

type 1 pilli (Ecoli)

virulence factor that allows infection in kidney and pathogen

PAP (pylonephritis associated pilli (Ecoli)

virulence factor that promotes kidney stone production adn pathogen

urease - proteus species

virulence factor that promotes upper UTI

flagella

what do you test for in urine dipstick test

nitrites - if high lots of bacteria | WBCs

treatment for uncomplicated UTI

trimethoprim, alkalinise urine

treatment for pyeloneophritis

trimethoprim

what classifies as recurrent UIT

>2 in 6 months

what causes dysentry

shigella, EIEC

what causes travellers diarrhoea

ETEC

what causes haemorrhagic colitis

EHEC

what causes enteric fever

salmonella typhi and paratyphi a and b

virulence factors of EPEC

intimin, Bfp, T3S effectors

adhesive enterotoxigenic

ETEC, cholera

adhesive with brush border damage

EPEC

invasion restricted to mucosa

shigella/EIEC

invasion of submucosa

campylobacter, salmonella

two stages of EPEC adherence

1. plasmid mediated initial attachment with Bfp on intact microvilli 2. chromosomal mediated attachment effacement - type 3 secretion system, Tir (R for intimin), intimin, effector proteins

e.g of cytotonic exotoxin

cholera, LT, ST

e.g. of cytotoxin exotoxin

shiga toxin

two enterotoxins of ETEC

ST and LT

mech of action of enterotoxins of ETEC

ST - resembles guanylin - cGMP LT - resembles cholera toxin, cAMP --> disruption of Na uptake and secretion of Cl - inhibition of absorption

when should you treat diarrhoea

``` cholera typhoid fever immunocompromised severe shigella giardia, pseudomembranou colitis - metramidazole ```

when SHOULDNT you treat diarrhoea

EHECT - bc ABs cause increased shiga toxin production

4 phyla of microbiota

firmicutes bacteroidetes actinobacteria proteobacteria

antigen access from GIT

M cells | DCs in mucosa

what are normal T cells in GIT

Treg (TGFbeta) and Th2 (IgA)

problem with kwashiorkor

severe undernutrition - microbiome produced chemical products resulting in inhibition of TCA cycle - decreased energy metabolism

definitive host

development occurs and parasite reaches sexual maturity

resevoir host

animal that normally infected with parasite that also infects humans

paratenic host

infection occurs but cannot replicate/develop

intermediate host

development occurs but cannot react sexual maturity

difference between helminths and protozoa

helminths are multicellular, protozoa and unicellular

anal worm in children

enterobius

huge worm

ascaris lumbricoides

skin penetration and autoinfection

strongyloides

fresh water snails

schistoma

haditid cysts

echinococcus

cyst formation in brain

taeniasis solium

2 tapeworms

echinococcus granulosus | taeniasis saginata and solium

1 fluke/trematode

schisoma

3 roundworms/nematodes

pinworm - enterobius ascaris strongyloides

micro Flashcards

(109 cards)