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Flashcards in Antibiotic resistance and new antibiotics Deck (45)
1

Linezolid
-coverage
-MOA
-what drugs do you have to avoid because of interactions?

Gram positiives including hVISA, VISA, MRSA
plus mycobacteria and nocardia

Not strep viridans or milleri

Inhibits protein synthesis

MAO inhibition so avoid SSRIs and Tramadol

2

Daptomycin
-coverage
-MOA

Most gram positives; like vanc with VRE coverage
Not good for VISA, VRSA
Inhibited by surfactant so not for pneumonia

Binds cell membrane and inhibits synthesis of DNA, RNA, protein

Bactericidal

3

Tigecycline
-coverage
-MOA

For Gram positives
Bacteriostatic for MRSA, MSSA, VISA, VRE
Also lots of gram negatives but NOT pseudomonas

Bacteriostatic

Protein synthesis inhibitor

4

Ceftaroline
-coverage
-MOA

For gram positives
Novel cephalosporin active against MRSA (incl hVISA, VISA)
NOT VRE
Good for gram negatives except ESBLs
Does kill pseudomonas

5

Colistin
-coverage
-MOA

Binds and disrupts outer cell membrane-->leakage and death

Very renal and neurotoxic


Works: pseudomonas, acinetobacter, E coli, Klebsiella, salmonella, some enterobacter

Does not work: Burkholderia cepacia, Proteus, Serracia, Proteus, Morganella, gram positives

6

Fosfomycin
-coverage
-MOA

Inhibits the MurA enzyme
Bacterocidal

Used for resistant UTIs not pseudomonas

7

Ertapenem
-coverage
-role

Newer carbopenem covers ESBLS but not with pseudomonas cover
Once daily IV

8

Moxifloxacin
coverage

Very broad spectrum
Not pseudomonas- go for cipro

Monitor QT

9

How is pseudomonas resistant to carbapenems?

porins -->reduced penetration

10

How is pneumococcus resistant to macrolides?

mef mutation-->efflux

11

What is the concern with over use of anti-anaerobic antibiotics?

Metro or Aug kill anaerobes and are take up by enterococcus -->new resistance VRE

12

What is conjugation?

Where pilus between two cells allows transfer of a mobile plasmid

13

What is transformation?

eg VRE strains

A bacterial cell dies and bursts with fragments of DNA released-->enterococcus takes up and integrates into own DNA

14

What is transduction?

Phages attach and infect and break up and package host DNA then infect new host with new DNA incorporated

15

What is the new classification for MRSA?

No longer community and hospital acquired but

MRSA vs NORSA (non multiply resistant oxacillin resistant staph)

NORSA usually susceptable to bactrim, macrolides, clindamycin, gent

16

What is the virulence gene for MRSA?

Panton Valentine leucocidin
(encodes pore forming toxin that punches holes in neutrophils)

17

How is s aureus defined according to reduced vancomycin susceptibility?

MRSA/VSSA = MIC under 2 for vanc
VISA when MIC 4-8
VRSA when MIC over 16

18

What is hVISA

the intermediate stage between MRSA and VISA- some colonies of each,
MIC usually 1-2 for vancomycin

Associated with thickened cell wall and more D-ala-D-ala targets for vancomycin- vanc failures common

19

Treatment for hVISA?

LINEZOLID

20

VISA- which patients?

dialysis patients
infected foreign bodies eg LVAD
similar treatment options to hVISA

21

What is the target of vanc?

glycosyltransferase enzyme in the cell membrane that is making new peptidoclycan chains for the cell wall

Also bind d-ala-d-ala monomers

22

What is VRE? I mean which actual bugs?

Enterococcus faecalis and faecium

23

What genes give enterococcus the VRE status?

Van A (teicoplanin resistant)
Van B (teicoplanin sensitive)
"vancomycin resistance gene clustering"- change d-ala-d-ala to d-ala-d-lac. Cell also cleaves d-ala-d-ala into single units so that vanc cannot bind

24

How do you treat VRE?

Linezolid
Tigecycline
Daptomycin (not if already was on vanc though)
Not teicoplanin as a bit crappy

25

When S pneumoniae is resistant to penicillin?

It's not beta lactamase.... it's altered PBP!!

26

What are the four classes of beta lactamase?

A penicillinases
B Metalloenzymes
C Cephalosporinases
D Oxacillinases

27

What are the ESCAPPM organisms?

Those with class C beta lactamase enzyme due to AMP C

If put on cephtriaxone improve initially then the beta lactamase is induced and there is rebound

Eg
enterobacter
serratia
citrobacter
acinetobacter
providencia
proteus
morganella

28

What are ESBLs?
-what mutations?
-how did this happen?

Extended spectrum beta lactamases
-Class A
-Mutations in existing beta lactamase genes eg CTX-M most common, alsoTEM, SHV
-plasmid mediated transfer

Lots in klebsiella, E coli, Proteus
Can look sensitive to 3rd gen ceph in vitro
Probably linked to fluoroquinolone use

29

ESBL treatment?

Carbapenems
Colistin
Amikacin

30

What is a metallobetalactamase?
-why is it metallo
-which bugs
-how did the mutation get there
-resistant to what

zinc dependent
class B beta lactamase
pseudomonas and acinetobacter
plasmid mediated
resistant to all carbapenems and all beta lactams except aztreonam

an example is new delhi betalactamase

31

Treatment for NDM?

Colistin

32

What is MDR TB?

isoniazid
rifampicin

33

What is EDR TB?

isoniazid
rifampicin
moxifloxacin
at least one injectable agent like amikacin

34

How do you treat a paradoxical TB reaction?

Keep going with treatment
Steroids
Aspirate/excise where able

35

Is alcohol a risk for reactivation of latent TB?

Yes, but not a strong risk factor

36

What are the components of SMART-COP?

SBP under 90
Multilobar CXR
Albumin under 35
RR over 25 in under 50, 30 if over 50
tachycardia over 125
confusion new
oxygen under 93%/90% age based
pH under 7.35

more points for oxygen, pH, BP

37

When would you give metronidazole for aspiration?

Terrible gums
Foul sputum
Alcoholic
Cavitating lung lesion
Empyema or severe white out

38

Where would some one come from to think MERS coronavirus?

Arabian peninsula
South Korea

DPP4 on nonciliated bronchial ep cells is the binding point

39

How does flu get in?

Sialic acid bound by haemaglutinin
Neuraminidase allows daughter virions to be released from the infected cell

40

What factors give you severe flu?

Obese
Asthma
Immunosupressed
Pregnant
Low IgG and especially IgG2

41

If someone becomes very sick with MERS can consider...

Ribavirin plus interferon alpha 2b

42

Tight stenosis L main on angiogram....

syphilis! Tertiary

43

Alemtuzumab gives you what types of infections?

Fungal things!
HBV, CMV
TB

44

In abx terminology, what is MDR?

3 or more drug classes resistance

45

EDR in abx terminology?

2 or fewer classes left