Antimicrobials 1 Flashcards
What is conjugation? What cells can do conj?
F+ cells have plasmid with genes encoding sex pulus and conjugation
ONLY IN GRAM NEGATIVE bacteria
What are the inhibitors of cell wall synthesis?
Firmly: fosfomycin Bind to: Beta Lactams Bacteria's: Bacitracin Dumb: Daptomycin Valls: Vancomycin
For cell wall synth inhibitors to be active, what are 2 prereq?
- bacterial must be actively proliferating (cell wall synth)
- must have a cell wall (ie. mycoplasma, protozoa, fungi and viruses DO NOT)
What are the members of the Beta Lactam class?
Lactam –> mother
you must be out of your MIND, to think you can bring that PEN into my new CAR, take the MONOrail instead
- cephalosporin
- penicillins
- carbapenem
- monobactam
Which bacteria contains Beta Lactamase?
Staph aureus
What are the Beta Lactamase Inhibitors? How do they work?
when things are looking bad ie. bacteria is resistant
dont SULK, grab a cup of TEA, and CLAW that bacteria away with some ACID
- sulbactam
- tazabactam
- clavulinic acid
Resemeble Beta Lactams but HAVE NO BACTERIOCIDAL ACTIVITY
-just bind to the beta lactamases and inactivate them
Beta Lactams MOA?
1) Bind to PCP (penicillin binding proteins)
PCPs: transpeptidases required in the last step of peptidoglycan synth
2) activate autolytic enzymes (normally active at different checkpoints in the bacteria to cleave the peptidoglycan so that it can be crosslinked - but now that there is no peptidoglycan, it digests it’s own bacteria
**Bacteriocidal
Beta Lactams - bacteriocidal or bacteristatic?
Bacteriocidal
What are the classes of penicillins and its members?
- Natural penicillins: penicillin G (benzylpenicillin) and V
- Repository penicillins: procaine and benzathine
- Antistaph: dicloxacillin, methicillin, oxacillin, nafcillin
- diplo and nas take meth and oxy
- Extended Spectrum: ampicillin and amoxicillin
Pencillins spectrum?
All gram positive - wall is easily crossed
gram negative (get in via porins)
MOST ANAEROBES
Synergistic penicillin combination?
Pen + aminoglycosides (protein synthesis inhibitors)
penicillin helps the aminogly get inside of the cell
- empiric tx for INFECTIVE ENDOCARDITIS
- never put pen and amino in the same infusion fluid
-now because of penicillin resistance –> vancomycin is replacing penicillin in this combo
Penicllin resistance? High, low? Mechanisms?
High
- Beta Lactamase (s. aureus)
- mutations in PBP (ie. MRSA)
- decrease penetration of drug or inc efflux
What is MRSA?
Methicillin (type of anti-staph penicillin) resisitant staph aureus
Remember s. aureus has Beta Lactamase
so anti staph penicillins were made to combat this
BUT some forms of staph ALSO have mutations in PBP –> therefore the antistaph penicillins STILL dont work (ie. with methicillin)
Penicllin G is used for? susceptible to Beta lactamase?
Gram positives, and some gram negatives and most anaerobes
- SYPHILIS !!
- STREP !!
- susceptible pneumococci
yes - all penicillins are, except for Anti-Staph penicillins
Function of repository penicillins?
made to prolong duration of penicillin G
Repository penicillins administration route? half lives? which is used more?
Procaine: IM -not IV (pot tox)
half life: 12-24 hours
benzathine: IM
half life: 3-4 weeks –> used more
Normal half life of penicillin is around 30 mins
Penicillin G Benzathine is used for?
Syphilis
rheumatic fever prophylaxis
Penicillin V vs. G?
V has around the same spectrum, but even less gram neg
ACID STABLE
Penicillin G used for?
oral
mild infections
pharyngitis, tonsilitis, strep skin infections
Antistaph penicillins? names? resistant against MRSA?
dicloxacillin
methicillin
oxacillin
nafcillin
Beta Lactmases resistant (recall: Beta lactamase is in s.aureus)
BUT NOT MRSA resistant (PBP mutation)
Anti-Staph Penicillins are used for?
ONLY treating Staph with beta lactamase
What are the extended spectrum ampicillins? why are they extended spectrum?
Ampicillin and Amoxicillin (highest F out of all the penicillins)
same spectrum as penicillin G + GRAM NEGATIVES
Amoxicillin contraindicated for kids and pregnant?
NO. Commonly prescribed for pregnants and kids
Amoxicillin treats?
Middle ear infections
Upper resp tract infections
strep pharyngitis
pneumonia etc
same as ampicillin
