Principles of Antibiotics Flashcards
What is an antibiotic
Molecules that work by binding a target site on a bacteria
(Agents produced by micro-organisms that kill or inhibit the growth of other micro-organisms in high-dilution)
Antimicrobials
Molecules that work by binding a target site on a microorganism (worm, virus, fungus, protozoan, bacterium)
What groups of antibiotics impact cell wall synthesis?
Beta Lactams, Carbapenems, Monobactams
Name some classes of Beta Lactams
Penicillins, Cephalosporins
Beta Lactam antibiotics disrupt p_______ production
peptidoglycan
Beta lactam antibiotics bind covalently and irreversibly to the p_______ b_____ p____
penicillin binding proteins
Once the antibiotic has bound, the cell wall is disrupted and lysis occurs, resulting in a h________ or i_________ environment
hypo-osmotic or iso-osmotic
Name some types of antibiotics impact nucleic acid synthesis?
DNA Gyrase. RNA Polymerase
Name some types of antibiotics impacting protein synthesis
30S subunit, 50S subunit
How do bactericidal antibiotics work?
The agent kills the bacteria
How do bacteriostatic antibiotics work?
Prevent growth of bacteria .Ratio of Minimum Bactericidal Concentration to Minimum inhibitory Concentration of >4
True or false: the antibiotic with the lowest MIC (minimum bactericidal conentration) is the best antibiotic
False
What are the 2 major determinants of anti-bacterial effects?
Concentration and time that antibiotic remains on these binding sites
What drug is used against staphylococcus aureus?
Flucloxacillin (if that doesn’t work then vancomycin)
Bacteria can become resistant to antibiotics by changing the molecular configuration of antibiotic b_____ s___ or masks it
binding site
Bacteria can become resistant to antibiotics by destroying or inactivating the ______
antibiotic
Bacteria can become resistant to antibiotics by modifying the bacterial membrane p___ channel size, numbers and selectivity
porin
Bacteria can become resistant to antibiotics by the proteins in bacterial membranes acting as an e____ or e____ pump so level of antibiotic is reduced
export or efflux
Things to factor in about antibiotic safety when prescribing
Intolerance, allergy and anaphylaxis
Side effects
Age
Renal and Liver functioning
Pregnancy and breast feeding
Drug interactions
Risk of Clostridium difficile
What can stop beta-lactam antibiotics working?
Beta-lactamases (giving antibiotic resistance)
What was developed to combat beta-lactamases?
Beta lactamase inhibitor
What antibiotic is good for those with penicillin allergy? (are also good for some resistant bacteria)
Cephalosporins
What bacterias commonly causes cellulitis?
S. aureus, Group A,C,G streptococcus
What antibiotic is used for cellulitis?
Flucloxacillin
What antibiotic is used for s. pneumoniae?
PO amoxicillin, IV Benzylpenicillin
Other than penicillin, what is a common antibiotic used for gram positive bacteria such as MRSA
Vancomycin and Teicoplanin
Does Vancomycin easily cross the BBB?
No
Name some macrolides (for gram positive bacteria and atypical pneumonia)
Clarithromycin and erythromycin
What is a good antibiotic to use for cellulitis when the patient has a penicillin allergy?
Clindamycin (type of lincosamide)
What are aminoglycosides used for?
Gram-negative rods
Often combined with other antibiotics
Needs to be closely monitored because it can be toxic (ears)
Good for UTIs
Name a quinolone (for gram negative)
Ciprofloxacin, used for UTIs, has side-effects (aneurysms, intra-abdominal infections, lowers seizure threshold)
Can beta-lactams be used for gram negatives?
Yes as gram negatives do still have peptidoglycan walls just not as effective.
What are CPEs?
Carbapenemase producing Enterobacteriaceae
Most common cause of UTI, intra-abdominal infection
What do carbapenemase do?
Enzyme which inactivates carbapenem antibiotics
