LEC 16,17 - Inhibitors of Cell Wall Synthesis Flashcards
What are the beta-lactam antibiotics?
Penicillin
Cephalosporin
Carbapenems
Monobactams
What is polymixin used for?
Topically to treat Gram (-) infections in skin + eye + ear
What are the five ways that a bacteria can become resistant to pencillin?
Inactivation
Decreased permeability
Alteration to PBP
Autolytic enzymes not activated
Lack of Cell wall
What must imipenem be given with? Why?
Cilastatin
Rapidly inactivated by renal tubule dehydropeptidases. Cilastatin is a dehydropeptidase inhibitor
What is the general activty of ertapenem?
Wide variety of
gram+
gram-
anaerobic
Eneterobateriaceae
bacterial target of pencillinase resistant penicillins
Low activity againse certain gram +’s
Resistant to penicllinase
DOC - penicillinase producing Staphylocccocus areus
Which of the natural penicillins are resistant to gastric acid?
Penicillin V
How does B-lactamase stop B-lactams from being active?
Cleaves the B-lactam ring
What is the general activity of carbaenems?
Broad spectrum
Anaerobes
Gram (+)
Gram (-) rods
Antipseudomonal penicillins (2)
Piperacillin
Ticarcillin
How are cephalosporins excreted?
Unchanged by the kindey
What are your two atypical bacteria?
Chlamydia
Mycoplasma
What are the specific bacteria that 1st gen cephalosporins are good against?
E. Coli
Klebsiella pneumoniae
Proteus mirabilis
How do the glycopeptides work?
Sterically inhibit addition of subunits to the peptidoglycan backbone
What are the bacterial targets of antipseudomonal penicillins?
Those covered by extended spectrum penicillins + addition gram negative bacilli
NO KLEBSIELLA
Major treatment for Pseudomonas aeruginosa
What is the function of the cell wall in bacteria?
Bacteria are hyperosmolar to their environment. The cell wall prevents osmotic rupture
What is the adverse effects of imipenem?
Seizures can occur with high levels
Use carefully in patients with brain lesion, head trauma , or hx of CNS disorders
What is the general structure of gram positive bacteria?
Only layered structure external to cell membrane and is thick
Route of Admin - Pen G procaine
IM
What cephalosporin is the only one allowed in food animals?
Cephapirim
Cows, pigs, turkey, and chickens
Use - Ceftiofur
Respiratory infections
What is the big difference between bacteria and mammialian cells?
Rigid cell wall external to the cell membrane
How is vancomycin excreted?
Primarily unchanged via the kidney
What is Penicillin G not effective against?
Amoebae
Plasmodia
Rickettsiae
Fungi
Virus
Route of Admin - Pen G potassium
IV + IM
What is the real reason behind the loss of cell-wall integrity following treatment of CWSi?
Bacteria’s own cell wall remodeling enzymes aka autolysins
Cleave peptidoglycan bonds
If choosing carbapenems for a pseudomonas infection how is recommended to be given? WHy?
resistance occurs quickly
Give with aminoglycoside
Carbapenems (3)
Imipenem
Meropenem
Ertapenem
What is the rank of antipseudomonal activity?
Piperacillin > Ticarcillin
When should doses of cephalosporin be adjusted?
Renal impairment
Penicillinase ressitant penicillins (3)
Oxacillin
Cloxacillin
Methicillin
How does bacitracin work?
Inhibits the conversion to its active form of the lipid carrier that moves water soluble cytoplasmic peptidoglycan subunits through cell membrane to cell exterior
Use - Cefovecin
Skin and soft tissue infections
What is a very important thing to remember about monobactams (aztreonam) when it comes to theraputic use?
No cross sensitivty with penicillin, can give it to those who are allergic
B-lactamase inhibitor combo - Piperacillin
Tazobactam
What are the adverse effects of monobactams?
Phlebitis
Skin rash
Abnormal liver function
Route of Admin - Penicillin V
Oral
Use - Cefpodoxime
Skin and soft tissue infections in dogs
Natural penicillins (4)
Penicillin G potassium
Penicillin G benzathine
Penicillin G procaine
Pencillin V
How are natural penicillins excreted?
Active transport in the kidney
What is vancomycin useful against?
Penicillin + methicillin resistant staphylococcus aureus
Treating gram (+) infections in penicillin allergic patients