What are the beta-lactam antibiotics?
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?
Alteration to PBP
Autolytic enzymes not activated
Lack of Cell wall
What must imipenem be given with? Why?
Rapidly inactivated by renal tubule dehydropeptidases. Cilastatin is a dehydropeptidase inhibitor
What is the general activty of ertapenem?
Wide variety of
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?
How does B-lactamase stop B-lactams from being active?
Cleaves the B-lactam ring
What is the general activity of carbaenems?
Gram (-) rods
Antipseudomonal penicillins (2)
How are cephalosporins excreted?
Unchanged by the kindey
What are your two atypical bacteria?
What are the specific bacteria that 1st gen cephalosporins are good against?
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
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
What cephalosporin is the only one allowed in food animals?
Cows, pigs, turkey, and chickens
Use - Ceftiofur
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?
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
What is the rank of antipseudomonal activity?
Piperacillin > Ticarcillin
When should doses of cephalosporin be adjusted?
Penicillinase ressitant penicillins (3)
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
What are the adverse effects of monobactams?
Abnormal liver function
Route of Admin - Penicillin V
Use - Cefpodoxime
Skin and soft tissue infections in dogs
Natural penicillins (4)
Penicillin G potassium
Penicillin G benzathine
Penicillin G procaine
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
how can you prolong the time penicillin stays in the body? How does it work?
Tubular secretion partially blocked by probenecid
Used for severe infections
Can you take antipseudomonals orally?
Where is PBP located?
On the cytoplasmic membrane
What are the three groups of polymyxins?
Where is the antibacterial activity located in penicillin?
Intact B-lactam ring
What are the symptoms of penicillin toxicity?
Mostly just allergic reactions
What are the the six major groups of drugs that inhibit cell wall formation?
Extended spectrum penicillins
1st gen cephalosporins (4)
What is the general activty of 4th gen cephalosporins?
More resistant to B-lactamases
What do B-lactamase inhibitors not work against?
Methicillin-resistant, penicillinase-producing, Staphylococci
What is the structure of the bacterial cell wall?
Resistant to osmotic lysis in both gram positive and gram negative due to peptidoglycan
Convalently linked sacculus that surrounds bacterium
What are the two ways vancomycin inhibits cell wall synthesis?
1 - binding to D-ala-D-ala terminus of peptidoglcan peptide = prevention of crosslinking
2- inihibits transglycosylation which inhibits elongation of peptidoglycan and chain
What does resistance form against vancomycin?
1 - D-ala-D-ala replaced with D-ala-D-lactate
B-lactamase inhibitor combo - Amipicillin
What is the upside to using ertapenem?
Highly stable against beta-lactamases
What are the gram - bacteria that are targeted by extended spectrum penicillins? (5)
What is the major characteristic of penicillin excretion?
one of the fastest drugs to be excreted renally
Why is polymixin not used parenteral?
Use for cefazolin
What is the mechanism by which bacitracin works?
Interferes with final dephosphorylation step in the phospholipid carrier cycle
Impedes on mucopeptide transder to growing cell wall
Why is parenteral bacitracin used with extereme caution?
What is the general structure of gram negative bacteria?
Outer membrane external to very thin peptidoglycan layer
How is bacitracin most commonly used?
Prevent superficial skin + eye infections following minor injuries
What is polymixin B normally combined with?
Bacitracin for broad spectrum antibacterial effects
What are the gram + exceptions to 1st gen cephalosporin susceptibility?
What is the requirement for biological activity of penicillin?
What are the extra bacterial targets of the antipseudomonal pencillins?
What is the general activity of 2nd gen cephalosporins?
Increased activity against gram (-)
4th gen cephalosporin (1)
What drugs are contraindicated when using CWSi?
Protein synthesis inhibitors
What is the general activity of 1st gen cephalosporins?
good activity - gram + (cocci most)
moderate activity - gram -
What is the mechanism of action for polymixin B?
Interacts with phospholipids in bacterial cell wall membrane to produce a detergent-like effect + membrane disruption
What are the four things that cephalosporins do not work against?
Listeria monocytogene s
What group of bacteria are ICWS most effective against?
How is penicillin excreted?
10% glomerular filtration
90% tubular secretion
B-lactamase inhibitor combo - Ticarcillin
When is polymixin B administered orally?
Cattle + Swine
Treatment of Gram (-) enteric infections
When can polymixin B be used parenterally?
Severe cases in horses
Extended spectrum penicillins (2)
How is resistance to b lactamase inhibitors occurring?
Develope independently upon b-lactamase production
altered PBP production
What is the general activity of 3rd gen cephalosporins?
less active against gram + cocci
more active against Enterobacteriaceae
How do b-lactams function?
Prevent cross-linking reaction called transpeptidation
How do the CWS inhibitors cause cell death?
Route of Admin - Pen G bezathine
What is the general activity of Bacitracin?
What bacteria lack a cell wall?
Mycoplasma L forms
What are the regulations of vancomycin use in food animals
2nd gen cephalosporin
What are the bacterial targets of extended spectrum penicillin?
Lower gram + coverage
Extended gram - coverage
Anaerobic coverage (w/ penicillinase inhibitors)
What are the adverse reactions to vancomycin?
What are the bacteria that do not have the autolytic enzymes activate and therefore are tolerant to penicillin?
What does vancomycin have synergistic effects against?
What are the glycoeptides?
Use - Cefixime
Skin + Soft tissue + Urinary infections
What is the general activity of monobactams?
Relatively resistant to beta-lactamases
Active against gram(-) rods (pseudomonas)
No activity against gram + or anaerobes
What are the drugs the b lacatamase inhibitors are added with?
What specific bacteria do ICWS work the best against?
B-lactamase inhibitor combo - Amoxicillin
When is polymixin B bactericidal?
Gram (-) organism
What are the three B-lactamase inhibitors?
Two other cell wall synthesis inhibitors that are not in groups
3rd gen cephalosporins