Micro Lectures 1-4 Flashcards
(53 cards)
1
Q
primary mode of ATP gen for bac
A
glycolysis
2
Q
gram stain
A
g(+) = purple - thick cell wall
g(-) = pink - thin cell wall
method:
- crystal violet
- iodine: stab violet
- alcohol: wash out pruple: leaves the g(-) leaving it clear
- safranin: pink
3
Q
peptidoglycan
A
repetitive horizontal NAG and NAM with verticle peptide bridge help together @ 3rd peptide
- can have pentaglycine cross bridge
- L-ala
- D-glu/D-gln
- m-DAP/lys
- D-ala
- D-ala
4
Q
pep-gly synth
A
- cytoplasmic
- assembly of NAG and NAM and pentapeptide side chain
- inhib:
- fosfomycin: (-) NAM assembly
- cycloserine: (-) L-ala (~) D-ala, inhib formation of D-ala – D-ala
- “flip flop”
- bacterprenol carries across membraine
- inhib by bacitracin
- extracytoplasmic
- transpeptidation via PBP
- inhib:
- beta-lactam: inhib PBP enz (transpepsidase/carboxypeptidase): unable to linke NH2 (3rd) – C=O (4th)
- vanco: bind 4th and 5th D-ala’s together to prevent removal of 5th D-ala
5
Q
otitis media
A
common cause of middle ear infection in peds
- strep pneumoniae
amoxicillin pen middle ear well
6
Q
addn cell wall cmps of G(+)
A
teichoic acid
- repeating sugar-(P)
mycolic acid
- waxy lipid: stains with acid fast
- mycobacterium leprae, TB
7
Q
addn cell wall cmpts of G(-)
A
outer membrane
- porins
- LPS (endotoxin) –> STRONGEST assoc with sepsis
periplasmic space
- site of beta-lactamases
- in G(+) and G(-) but MORE for G(-)
8
Q
LPS
A
lipid A
- does all the toxic work: some G(-) contraindicated to tx with antibio due to this (EHEC)
- released as by-prod of bac cell dealth
core oligosacc
- branched polysacc essential for struc and viability
o-ag
- long linear polysacc
- LPS w/o this called LOS
- antigenic and highly variable
9
Q
gram staining for meningitis
A
fast!
- lumbar puncture –> CSF
- major mening
- g(+) = s. pneumo
- g(-) = n. meninigitis
10
Q
structures outside bac cell wall
A
- glycocalyx
- slime layer = loose = biofilm
- capsule = antiphago
- india ink
- quellung rxn
- fimbraie/pili
- sticky: pilin protein –> UTI (e.coli)
- g(-)
- conjugation
- flagella
- motility
11
Q
PM
A
lipid structure WITHOUT choles (except mycoplasma.pneumoniae)
- bilayer
- fx sim to euk cell wall
12
Q
nucleiod and plasmid
A
nucleoid = one circular chr
- NO histones! –> structure maint by polyamines
plasma: extrachr –> toxins/ resistance to antibio - can be txfed via conjugation
13
Q
ribosomes
A
70s: 30 + 50
14
Q
endospores
A
mostly G(+)
- bacillius, clostridium
15
Q
what place in the body has the most bac?
A
colon: anaero or facul anaero = g(-)
- e.coli
- bacteriodies
16
Q
bacterial interference
A
competitiions with normal flora and pathogens can clear foreign bac
17
Q
what med gives high risk for c.dff?
A
clindamycin
- STRONG antio –> kills off other bac in colon
- allows c.diff to prolif
18
Q
zoonotic
A
cap of infecting wide range of hosts
19
Q
fx of virulence factors
A
- colonize
- invade
- evade host imm
- dmg
***aided by toxins
20
Q
endotoxin fx (5)
A
- (+) macp –> TNF –> (+) T cells
- inflamm
- sequester iron
- (+) endothelial cells –> incr vasc permeability
- mast cells –> histamine, proinflam med
- aggregate platelets
- PMN
- hypoglycemia
*** ALL G(-)
21
Q
exotoxin
A
soluble
heat-labile
types:
- serotoxins = neurotoxins
- A/B: active/binding = MOST
- multiprotein delivery system
*** highly antigenic (specific)
usualy gets from plasmid conjugation
22
Q
septic shock
A
usually from g(-) LPS
- called superag from g(+)
bacteremia: bac in blood
23
Q
binary fission
A
asex: 20min
rate lim by how FAST DNA Pol works
24
Q
gene exchange
A
vert: mature –> progeny
horiz: mature –> mature
25
transformation
uptake of naked DNA from environ --\> homologous recombin
* haemophillis
* neisseria
26
conjugation
controlled by fertility factors (F plasmid) with sex pili (hollow)
* tra genes (txf genes)
* F(+) + F(-) --\> 2 F(+) cells
Hfr cells
* high-freq recombinant: plasmid incorp into DNA
* txf Hfr --\> F(-)
* not ALL of F(+) plasmid goes to daughter so daughter cell reminds F(-)
27
transduction
txf bac DNA by bacteriophage (virus that takes over bac)
* virus highjacks machinary to replication
* SOMETIMES! there is a phage with only bac genes
lytic = default
lysogenic = latent
* singals inside bac saying NOT ideal for replication so viral DNA gets integrated into bac chr --\> **prophage** --\> stab until ideal conditions
* prophage can exit lysogenic phase when conditions are met and enter lytic cycle
28
transposition
mobile gene: transposase
* makes blunt end cuts
* ligates IS10 to target 5' ssDNA
* cell DNA Pol extends 3' cut ends and ligase joins to IS10 5' ends
29
mech of antibio resistance
1. intrinsic
* lacks target mol
* mycoplasma = NO pepgly --\> resist beta-lac
2. chr-med
* mut of genes for PBP usu via **vertical** txf
3. plasmid-med
* R-plasmid for ab resistance
30
when is a good time to get sample for disease
during fever spike
31
ziehl-neelson
acid-fast: mycobacterium
32
MacConkey Agar: lactose fermenting
33
EMB - metallic green for e.coli
34
TSBC:
TSBC:
* vibrio ferments **sucrose** --\> orange
35
microaerophillic
grow in o2 with a bit of co2
* spirocetes: campylobac, h.pylori
36
ab susceptibility testing
after patho cultured, its sens to SPECIFIC AB serves as guide in choosing antimicro tx
37
bacteriostatic v bacteriocidal
static: "stalls" to allow immune def sys to eradicate bac "naturally"
* ingrain into memory
cidal: kill
38
meds used to tx
39
cell wall inhib
beta-lactam: disrupt pepgly layer by (-) txpeptidase
* pcn: most = G(+)
* cephalosporin
* monobactam: g(-)
* carbapenems: broad
thiazolidine ring
* (-) by beta-lactamases (penicillinase)
40
clavulanic acid
INHIB beta-lactamase --\> allows beta-lactams drugs to work
41
classification of pcns
natural
* G (benzyl)
* V - stable
beta-lactamase-resistant
* dicloxacillin: anti-beta-lactamase
* methicillin
aminopcn
* amoxicillin: **peds** - stable, fast absorption
* ampicilin
acyl ureidopcns
* piperacillin
42
pcn tox
among safest: tox from collateral loss of beneficial bac
* some allergy
* cephalosporin has same core ring as pcn
43
beta-lactamase inhib
combo uses: enhace activity of beta-lactams
* augmentin: clavulanic acid + amoxicillin
* unasyn: sulbactam + ampicillin
* zosyn: tazobactam + piperacllin
suicide inhib
44
cephalosporins
SAME ring shape as pcn
generations:
1. G(+)
2. G(-) \> G(+)
3. G(-) \>\> G(+):
* good penetration into CSF = drug of choice for meningitis
* ceftazidime
* **ceftriaxone**
4. wide spectrum: effective aga pseudomonas, most resistant to beta-lactamase
5. MRSA active
45
tetracycline
4 benzene ring core
bacteriostatic
* reversiblity binds 30s: blocks tRNA into acceptor site --\> prevent protein chain elong
doxycycline (2nd gen)
* also (-) mito ribosomes --\> (-) plasmodium (malaria parasite)
46
tetracycline tox (7)
1. celate to Ca2+:
* **dark staining teeth**
* not for preggs, kids
2. **hepatotox** in preg
3. NEED empty stomach
* inpaired absorption in combo with di/tri valent cations
4. azotemia: abnorm high N-containg cmpds in blood
5. fanconi syndrome: prob in prox renal tube absorption
* doxycycline better for renal pts
6. vertigo (minocycline)
7. photosens
47
macrolides
binds 50s ribosome and dissociated peptidyl-tRNA: inhib RNA-dep protein synth @ chain elong
* prevents ribo mvmt
ex:
* erythromycin
* azithromycin (z-pack)
* clarithrimycin ("clear" - h.pylori)
48
fluroquinolones
blocks DNA gyrase (top II) and top IV: prevents un-supercoiling
* can also restore negative supercoiled config of bac chr during and ofllowing DNA replication
ex:
* **FL**oxacin:
* cipro
* levo
* nor
* o
* nalidixic acid
**\*\*\*1st line tx for UTIs**
49
quinolone tox (6)
1. **dmg growing cartilage**
* c/i in pts \< 18 and pregs
2. tendon rupture (achilles)
3. oral absorption imapred by di/tri-valent cations
4. GI
5. gonorhhea, chlamydia = higly resistant
6. photosens
50
superag
simul binds MHC II and T cells
(+) LOTS of T cells
incr secr of proinflamm cytokines: TNF-alpha, IL-1
51
mannitol salt agar
52
hemolytic patterns on blood agar
53
PYR test
ab of s.pyogenes to enq hydrolyze L-pyrrolidonyl-beta-naphthylamide
* diff from other group A strep
