-
How does IDSA categorize skin and soft tissue infections?
Purulent vs non-purulent
-
What is the usual organism found in purulent skin infections?
Staphylococcus aureus
-
What is the usual organism found in non-purulent skin infections?
Group A Streptococci
-
What are characteristics of non-purulent skin infection?
- Necrotizing infection
- Cellulitis
- Ersipelas
-
What are the characteristics of purulent skin infection?
- Furuncle
- Carbuncle
- Abscess
-
What is the initial treatment for a severe skin infections?
Empirically treat with vancomycin and piperacillin/tazobactam, if suspected Staph. aureus, must cover MRSA
-
What route of administration would you use to treat moderate non-purulent skin infection?
IV
-
What is the drug used to treat moderate non-purulent skin infection?
IV penicillin
-
What route of administration would you use to treat mild non-purulent skin infection
Oral
-
What are the drugs used to treat mild non-purulent skin infections?
Oral penicillin or dicloxacillin
-
What is the drug used to treat moderate purulent skin infection?
Oral TMP or doxy
-
What is the drug used to treat severe purulent skin infection?
IV Vancomycin
-
What is defined therapy?
It is after you do a C&S and have a target organism, can then deescalate abx treatment
-
What is the mechanism of action of clindamycin?
Inhibits protein synthesis by binding to 50S ribosomal subunits of microbe
-
Which bacteria do clindamycin target?
- Gr+ aerobes such as Group A and B Streps, S.penumoniae and S.aureus including MSSA, MRSA
- Gr- anaerobes such as Bacteroides
-
True/False: Clindamycin has antimicrobial activity on Gr- aerobes like E.coli
False; Clindamycin targets Gr+ aerobes and Gr- anaerobes
-
What are some clinical indications for clindamycin?
- Oral and IV forms to treat systemic infections; Necrotizing fasciitis
- Topically to treat acne
- Intravaginally to treat for bacterial vaginosis
-
If a patient is allergic to beta-lactam (penicillin), is it safe to give clindamycin?
Yes
-
How would you treat Necrotizing fasciitis?
Penicillin G and Clindamycin
-
What are the adverse side effects of Clindamycin?
- Diarrhea (from oral form)
- At risk to develop C.diff colitis
-
Is Clindamycin a good drug for MSSA / MRSA?
Not anymore, it used to be. Now, it is only about 79% MSSA susceptible and 72% MRSA susceptible to clindamycin
-
Is Clindamycin a good drug for Bacteroides?
Not anymore, it used to be.
-
What is the mechanism of action for penicillin?
Inhibit cell wall synthesis
-
What makes penicillin unique?
It has beta-lactam , which is a four sided ring
-
How does beta-lactam affect bacterial cell wall?
Inhibit the formation of bacterial cell wall by binding to the transpeptidase enzyme which inhibit the cross-linking of the peptidoglycan
-
What happens to the bacteria cell that is without cross-linking of peptidoglycan?
Weakened cell wall, leading to intracellular osmotic pressure and rupturing of cell wall
-
How do bacteria become resistant to penicillin?
They develop a different transpeptidase (penicillin binding protein) where penicillin cannot bind
-
What is beta lactamase and what is the significant of it?
It is a bacterial enzyme that can breakdown beta-lactam (penicillin), thereby resistant to Penicillin
-
How do Gr- bacterial resistant to penicillin?
- Outer membrane permeability
- Efflux pump
- B-lactamase production
-
What are the B-lactamases produced by Gr- bacteria?
- ESBL (extended spectrum B-lactamases)
- KPC (Klebsiella penumoniae carbapenemases)
- MBL (Metallo-B-lactamases: NDM, IMP, VIM)
-
Bacteria that produce ESBL enzymes can be killed by which abx?
Carbapenem antimicrobial
-
Bacteria that produce carbapenemase (KPC, MBL) are resistant to what?
Most beta-lactam antibiotics
-
What are the four types of penicillin?
- Natural penicillin
- B-lactamase resistant
- Aminopenicillins
- Extended spectrum penicillin
-
What are natural penicillins and what are they a drug of choice for?
- Penicillin G (IV, IM depot)
- Pencillin V (oral)
- Drug of choice for Group A Strep
-
What are B-lactamase resistant penicillin and what are they a drug of choice for?
- Oxacillin
- Naficillin
- Dicloxacillin
- Drug of choice for MSSA
-
What are aminopenicillin?
-
What are extended spectrum penicillin?
- Ticarillin (supplied with clavulanic acid)
- Piperacillin (supplied with tazobactam)
-
Which penicillin contain B-lactamase inhibitor?
- Ampicillin plus sulbactam (IV)
- Amoxicillin plus clavulanic acid (oral)
- Ticarcillin plus clavulanic acid (IV)
- Piperacillin plus tazobactam (IV)
-
Which drug can be used to prolong the half-life of penicillin?
Probenicid
-
Is penicillin safe during pregnancy?
Yes
-
What are some adverse reactions for penicillin?
- Seizures from high levels
- Cause C.diff infection
-
Which bacteria are penicillin most effective against?
Gr+; GAS, GBS, S.pneumonia, MSSA
-
True/False: Penicillin is good against MRSA?
False
-
What is the mechanism of action of Vancomycin?
Inhibition of bacterial cell wall synthesis
-
What is the antimicrobial spectrum of activity for vancomycin?
- Gr+ aerobes
- Gr+ anaerobes
-
What are the bacteria targeted by vancomycin?
- GAS, GBS
- Strep. pneumo
- MSSA, MRSA
- Clostridium difficile
- Enterococci
-
Is vancomycin the drug of choice for MRSA?
YES!
-
How does vancomycin disrupt the cell wall synthesis?
Bind terminal ALA-ALA on peptide chain to prevent peptidoglycan cross-link
-
How do vancomycin resistance develop?
D-Lactate replaces the last Alanine on NAM peptide so no vancomycin binding
-
Which route of administration of vancomycin is optimal for MRSA and MSSA?
IV
-
What does oral/rectal routes of administration of vancomycin useful against?
C.diff because of local effect
-
What are some possible adverse effects of IV vancomycin?
- “Red neck” syndrome when infusing IV doses too rapidly
- Allergic reaction
- IV administration leads to vein irritation or phlebitis
- Nephrotoxicity
- Ototoxicity
-
How to avoid high peak levels of vancomycin?
Slow infusion rate
|
|
