0516 - Antibiotics - EG Flashcards
What is an antimicrobial?
a chemical that inhibits the growth of or kills microorganisms
What is an antiseptic?
antimicrobial applied to skin
What is a disinfectant?
antimicrobial applied to objects.
What is a bactericidal agent?
one that kills bacteria
What is a bacteriostatic?
one that inhibits the growth of bacteria
What is the treatment plan in selecting an antibiotic for a patient?
- Empirical treatment - choice antibiotic based on the most likely bacterial cause of the infection and the most effective antibiotic based on known sensitivity data.2. Directed treatment - choice of antibiotic based on the results of the culture to antibiotic sensitivity tests.
What are the main gram negative bacilli that cause disease?
Enterobacteriaceae family (E. coli)Pseudomonas aeruginosaHaemophilus influenzae
What are the main gram positive cocci that cause disease?
Staphylococcus sp, streptococcus sp, enterococcus sp.
What is the main antibacterial against strict anaerobes.
metronidazole
What are some atypical bacterial species that cause infection
Mycoplasma, mycobacterium, listeria, syphilis
What are the main bacterial cell functions that antibiotics target?
cell wall synthesisprotein synthesisDNA synthesisRNA synthesisfolic acid synthesis
What type of antibiotics are inhibitors of cell wall synthesis?
beta lactam antibioticsglycopeptides
How to beta lactam antibiotics function?
prevent peptide bridges between adjacent peptidoglycan strands by inhibiting transpeptidase activity on the penicillin binding site.
What are some examples of beta lactam antibiotics?
Penicillin, cephalosporin, flucloxacillin, amoxicillin
What is penicillinase?
An enzyme produced by bacteria that breaks down penicillin
What are cephalosporins?
broad spectrum antibiotics produced by the fungus Cephalosporium, often given to patients with penicillin allergies (~10% cross reactivity)
What are the two main bacterial species that cephalosporins (all generations) do not act against?
listeria and enterococcus
What was the main development with the progression from first to fourth generation cephalosporins?
More cover against gram negative bacteria
What generation of cephalosporins are effective against pseudomonas a.?
fourth
Listeria is sensitive to?
penicillin
What is the main antibiotic used against staph infections?
flucloxacillin
What is one of the benefits of amoxicillin to penicillin?
Amoxicillin is better absorbed and more affective against gram negatives.
What are the two glycopeptide antibiotics? What type of gram are they effective against? What is the main use?
vancomycin and teichoplaninonly effective against gram positive, Vancomycin used against MRSA
How do antibiotics affect protein synthesis within bacteria?
by inhibiting function of the 30S or 50S ribosome
What are aminoglycosides used to treat?What is the main antibiotic of this type?What toxicity can they cause?
Broad spectrum gram negative bacteriaGentamycinototoxicity - leading to deafness or loss of vestibular functionNephrotoxicity 9often reversibly)
What type of bacteria are macrolides used to treat?
Gram positive bacteria
Name some macrolide antibiotics.
erythromycin, clarithromycin, azithromycin (chlamydia)
What is a ADME benefit of macrolides and similarly tetracyclines and quinolones?
good oral bioavailability
What is the choice of treatment against mycoplasma and chlamydia, and as a prophylaxis to malaria?
tetracycline, doxycycline
What are some antibiotics that inhibit DNA synthesis? How do they function?
Ciprofloxacin (inhibited in Australia) and norfloxacinBy inhibiting DNA gyrase, causing stress on DNA in replication and thereby inhibiting replication.
What Gram type do quinolones cover?
negative
What can be used to treat Pseudomonus?
gentamycin and quinolones
What type of class is a broad spectrum against anaerobic bacteria?
Nitroimidazoles
What class of anitbiotic can be used to treat against trichomonas giardia, entamoebab histolytica
Nitroimidazoles
List antibiotic drugs that inhibit folic acid synthesis
Trimethoprim, bactrim
What is an adverse effect of folic acid inhibiting antibiotics
anaemia
What is the main type of infection that trimethoprim is used to treat?
Urinary tract infections
How do some bacteria escape antibacterial drugs?
increased elimination via efflux pumps,drug inactivating enzymesdecreased uptakeby altering drug moiety
