Flashcards in Antibiotic resistance and new antibiotics Deck (45)
-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
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
For Gram positives
Bacteriostatic for MRSA, MSSA, VISA, VRE
Also lots of gram negatives but NOT pseudomonas
Protein synthesis inhibitor
For gram positives
Novel cephalosporin active against MRSA (incl hVISA, VISA)
Good for gram negatives except ESBLs
Does kill pseudomonas
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
Inhibits the MurA enzyme
Used for resistant UTIs not pseudomonas
Newer carbopenem covers ESBLS but not with pseudomonas cover
Once daily IV
Very broad spectrum
Not pseudomonas- go for cipro
How is pseudomonas resistant to carbapenems?
porins -->reduced penetration
How is pneumococcus resistant to macrolides?
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
What is conjugation?
Where pilus between two cells allows transfer of a mobile plasmid
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
What is transduction?
Phages attach and infect and break up and package host DNA then infect new host with new DNA incorporated
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
What is the virulence gene for MRSA?
Panton Valentine leucocidin
(encodes pore forming toxin that punches holes in neutrophils)
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
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
Treatment for hVISA?
VISA- which patients?
infected foreign bodies eg LVAD
similar treatment options to hVISA
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
What is VRE? I mean which actual bugs?
Enterococcus faecalis and faecium
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
How do you treat VRE?
Daptomycin (not if already was on vanc though)
Not teicoplanin as a bit crappy
When S pneumoniae is resistant to penicillin?
It's not beta lactamase.... it's altered PBP!!
What are the four classes of beta lactamase?
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
What are ESBLs?
-how did this happen?
Extended spectrum beta lactamases
-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
What is a metallobetalactamase?
-why is it metallo
-how did the mutation get there
-resistant to what
class B beta lactamase
pseudomonas and acinetobacter
resistant to all carbapenems and all beta lactams except aztreonam
an example is new delhi betalactamase
Treatment for NDM?
What is MDR TB?
What is EDR TB?
at least one injectable agent like amikacin
How do you treat a paradoxical TB reaction?
Keep going with treatment
Aspirate/excise where able
Is alcohol a risk for reactivation of latent TB?
Yes, but not a strong risk factor
What are the components of SMART-COP?
SBP under 90
Albumin under 35
RR over 25 in under 50, 30 if over 50
tachycardia over 125
oxygen under 93%/90% age based
pH under 7.35
more points for oxygen, pH, BP
When would you give metronidazole for aspiration?
Cavitating lung lesion
Empyema or severe white out
Where would some one come from to think MERS coronavirus?
DPP4 on nonciliated bronchial ep cells is the binding point
How does flu get in?
Sialic acid bound by haemaglutinin
Neuraminidase allows daughter virions to be released from the infected cell
What factors give you severe flu?
Low IgG and especially IgG2
If someone becomes very sick with MERS can consider...
Ribavirin plus interferon alpha 2b
Tight stenosis L main on angiogram....
Alemtuzumab gives you what types of infections?
In abx terminology, what is MDR?
3 or more drug classes resistance