Cell Wall Syn Inhibitors Flashcards
What are the 4 Beta Lactams
Penicillins, Cephalosporins, Carbapenems, Aztreonam
What are the two extended spectrum penicillins
Aminopenicillins (Amp & Ammox) Antipseudomonal penicllins (piper and ticar)
What is the importance of PBPs and where are they located
It is an enzyme needed for cell wall synthesis and located on bacterial cytoplasmic membrane
When can beta lactams kill bacteria
They can kill only when bacteria are actively growing and synthesizing cell wall
What are the four mechanisms of resistance to B Lactams
B Lactamase, Change in PBP structure, Change in porin structure (impaired penetration of the drug to PBP), Efflux Pumps
Who has a greater sensitivity to B Lactamases? Penicillins or cephalosporins
Penicillins do. The cephalos arent as sensitive to the lactamases
Which lactamases hyrdolyze both penicillins and cephalos?
Extended Spectrum B Lactamases (ESBL)
Which class of penicillins are resistant to penicillinases and cephalosporinases
Carbapenems
What is the mechanism of resistance for MRSA, PRSP, and resistant Enterococci species?
Altered PBPs to methicillin for MRSA, penicillin for PRSP and Enterococci. These bugs produce PBPs with a low affinity of binding to B lactams
What is the mechanism for gram - bugs?
Gram (-) bugs have outer cell wall. B Lactams cross this outer membrane and enter via PORIN CHANNELS. Absence or improper porin channels impair drug entry. This is the case with Pseudomonas.
Gram (-) may also have an efflux pump
What are the natural penicillims
G & V bc they can purified from mold
What is the spectrum for natural penicillins? (Basically, who do they work on?)
Mostly gram+ and non b lactamase producing anaerobes
-Strep (pyogenes, viridians, pneumococci (susceptible)
- Enterococci (thats susceptible)
- Treponema Pallidum for Syphillus (Spirochete)
- Leptospira (Sprirochete)
- Clostridium species (except C. diff…thats metronizadole)
What is Peni G used for and how is it administered?
Group A Strep
Dental Infections
Given Orally
What is Peni V used for and how is it administered?
Pneumococcal Pneumonia (susc)
Strep Endocarditits
Neurosyphillis
Given IV
What is Benzathine Penicillin, what is it used for, and how is it given?
It is a form of penicillin that is long lasting and slowly absorbed into the circulation. Use this when low doses of prolonged time intervals are needed
Syphilis
Group A Strep
Erysipelas/Cellulits
Given IM
How is neurosyphilis treated?
With IV penicillin for two weeks OR…
Daily IM benzathine penicillin PLUS probenecid
What is probenecid and how does it work?
Probenecid is a drug that raises blood levels of penicillin, this impairs renal tubular secretion of penicillin
It promotes renal clearance of uric acid by blocking urate anion exchangers in prox tubule
Used to treat gout
What is nafcillin?
It is an antistaphylococcal that is RESISTANT to penicillinases.
Oxacillin is an alternative
Use Naf for Staph
MSSA Endocarditis or Strep Cellulitis
MRSA resistant
75% of S. Epidermidis is resistant
Can cover strep, but not as good as natural PCN
Dicloxacillin is the older version of which penicillin
hint: its a very narrow spectrum lactam
Nafcillin.
Methicillin is also an older version of this type
What are the penicillins that are resistant to lactamases and what do they treat?
MNO
They are used to treat MSSA (methicillin sensitive)
75% of S. epidermidis are resistant
Covers strep as well but not as good as natural penicillins
What is a advantage that wide spectrum lactams have over narrow/very narrow?
Better activity against gram- bc they can penetrate their outer membrane much better
Still resistant to lactamases tho
What are the two aminopenicillins?
Ampiciilin; IV or PO
Ampicillin + Sulbactam; IV
Ammoxicillin PO (better absorbed than ampi) Ammox + Clav Acid; PO
What bugs/infections are the aminopenicillins used for?
Used for:
UTI
Otitis
Sinusitis
Bites
Bugs: Strep Some Enterococci, H. Influenza, Enterobactericiae Listeria Anaerobes
What are the Ureidopenicillins?
These are aka the Antipseudomonal penicillins.
Pipercillin with Tazobactam (commonly used)
Ticarcillin with Clav Acid (rarely used)