Antibiotic resistance and new antibiotics Flashcards Preview

ID > Antibiotic resistance and new antibiotics > Flashcards

Flashcards in Antibiotic resistance and new antibiotics Deck (45)
Loading flashcards...
1
Q

Linezolid

  • coverage
  • MOA
  • what drugs do you have to avoid because of interactions?
A

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
Q

Daptomycin

  • coverage
  • MOA
A

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
Q

Tigecycline

  • coverage
  • MOA
A

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

Bacteriostatic

Protein synthesis inhibitor

4
Q

Ceftaroline

  • coverage
  • MOA
A
For gram positives
Novel cephalosporin active against MRSA (incl hVISA, VISA)
NOT VRE
Good for gram negatives except ESBLs
Does kill pseudomonas
5
Q

Colistin

  • coverage
  • MOA
A

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
Q

Fosfomycin

  • coverage
  • MOA
A

Inhibits the MurA enzyme
Bacterocidal

Used for resistant UTIs not pseudomonas

7
Q

Ertapenem

  • coverage
  • role
A

Newer carbopenem covers ESBLS but not with pseudomonas cover

Once daily IV

8
Q

Moxifloxacin

coverage

A

Very broad spectrum
Not pseudomonas- go for cipro

Monitor QT

9
Q

How is pseudomonas resistant to carbapenems?

A

porins –>reduced penetration

10
Q

How is pneumococcus resistant to macrolides?

A

mef mutation–>efflux

11
Q

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

A

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

12
Q

What is conjugation?

A

Where pilus between two cells allows transfer of a mobile plasmid

13
Q

What is transformation?

A

eg VRE strains

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

14
Q

What is transduction?

A

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

15
Q

What is the new classification for MRSA?

A

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
Q

What is the virulence gene for MRSA?

A

Panton Valentine leucocidin

encodes pore forming toxin that punches holes in neutrophils

17
Q

How is s aureus defined according to reduced vancomycin susceptibility?

A

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

18
Q

What is hVISA

A

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
Q

Treatment for hVISA?

A

LINEZOLID

20
Q

VISA- which patients?

A

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

21
Q

What is the target of vanc?

A

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

Also bind d-ala-d-ala monomers

22
Q

What is VRE? I mean which actual bugs?

A

Enterococcus faecalis and faecium

23
Q

What genes give enterococcus the VRE status?

A
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
Q

How do you treat VRE?

A

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

25
Q

When S pneumoniae is resistant to penicillin?

A

It’s not beta lactamase…. it’s altered PBP!!

26
Q

What are the four classes of beta lactamase?

A

A penicillinases
B Metalloenzymes
C Cephalosporinases
D Oxacillinases

27
Q

What are the ESCAPPM organisms?

A

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
Q

What are ESBLs?

  • what mutations?
  • how did this happen?
A

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
Q

ESBL treatment?

A

Carbapenems
Colistin
Amikacin

30
Q

What is a metallobetalactamase?

  • why is it metallo
  • which bugs
  • how did the mutation get there
  • resistant to what
A
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
Q

Treatment for NDM?

A

Colistin

32
Q

What is MDR TB?

A

isoniazid

rifampicin

33
Q

What is EDR TB?

A

isoniazid
rifampicin
moxifloxacin
at least one injectable agent like amikacin

34
Q

How do you treat a paradoxical TB reaction?

A

Keep going with treatment
Steroids
Aspirate/excise where able

35
Q

Is alcohol a risk for reactivation of latent TB?

A

Yes, but not a strong risk factor

36
Q

What are the components of SMART-COP?

A
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
Q

When would you give metronidazole for aspiration?

A
Terrible gums
Foul sputum
Alcoholic
Cavitating lung lesion
Empyema or severe white out
38
Q

Where would some one come from to think MERS coronavirus?

A

Arabian peninsula
South Korea

DPP4 on nonciliated bronchial ep cells is the binding point

39
Q

How does flu get in?

A

Sialic acid bound by haemaglutinin

Neuraminidase allows daughter virions to be released from the infected cell

40
Q

What factors give you severe flu?

A
Obese
Asthma
Immunosupressed
Pregnant
Low IgG and especially IgG2
41
Q

If someone becomes very sick with MERS can consider…

A

Ribavirin plus interferon alpha 2b

42
Q

Tight stenosis L main on angiogram….

A

syphilis! Tertiary

43
Q

Alemtuzumab gives you what types of infections?

A

Fungal things!
HBV, CMV
TB

44
Q

In abx terminology, what is MDR?

A

3 or more drug classes resistance

45
Q

EDR in abx terminology?

A

2 or fewer classes left