antbiotics

Question 1

types of cell wall synthesis inhibitors

Answer 1

beta-lactam antibiotics, cephalosporins, other drugs

Question 2

types of protein synthesis inhibitors

Answer 2

tetracyclines, macrocodes and other drugs

Question 3

types of folic acid synthesis inhibitors

Answer 3

sulfonamides, trimethoprim

Question 4

Types of DNA synthesis inhibitors

Answer 4

quinolones

Question 5

principles of antibiotic therapy

Answer 5

harm the parasite and not the host, mechanism of action affects processes unique to bacteria, processes common to bacteria and the host cell (more affinity for bacteria), type of bacteria (gram +, gram -, anaerobic, aerobic)

Question 6

beta-lactam antibiotics (penicillin) characteristics

Answer 6

unstable in acidic pH and susceptible to destruction by beta-lactamase (when antibiotic is killed there is a risk of super infection), inhibit bacterial growth by impeding cell wall synthesis

Question 7

super infection

Answer 7

caused by the antibiotic being killed, bacteria multiply out of control causing major infection and diarrhea

Question 8

what does penicillin treat

Answer 8

streptococcous, meningococcous, anthrax, clostridium etc

Question 9

penicillin side effects

Answer 9

non-toxic, serious effect due to hypersensitivity (anaphylactic shock), diarrhea (superinfection), yeast infection, resistance (90% of staph are beta-lactamase producers)

Question 10

types of semi-synthetic penecilin

Answer 10

ampicillin, amoxicillin, methicillin

Question 11

drug therapy guidelines

Answer 11

importance of correct doses, important to take the dose at correct time because drugs are only effective if there are enough in the blood

Question 12

beta-lactam antibiotics (cephalosporins)

Answer 12

similar to penicillin (chemically, mechanism of action and toxicity), more stable to bacterial beat-lactamase, may cross blood-brain barrier, can be used in cases of penicillin sensitivity but are also sensitizing, given PO/IM/IV

Question 13

what creates triple antibiotic therapy

Answer 13

bacitracin, polymyxin and neomycin

Question 14

tetracycline characteristics

Answer 14

broad spectrum, accumulates inside the bacterial cell, binds to ribosomes, impeding formation of new protein, chelates calcium and other divalent cations, given PO or IV,

Question 15

What type of horses should not have tetracyclines

Answer 15

young horses or pregnant mares because it binds to calcium,all drugs are only effective if they are free in the blood stream. oxytetracycline may be given to foals with contracted tendons so the calcium becomes bound and the tendons relax

Question 16

macrolides

Answer 16

prevent bacterial protein synthesis, examples are erythromycin, clarithromycin, azythromycin, erythromycin is used in conjunction with rimfampin to treat pneumonia in foals, may cause diarrhea and light sensitivity (foals need ti be kept inside), fever, can be fatal in adult horses. used in young horses being treated for lawsonia

Question 17

other protein synthesis inhibitors

Answer 17

aminiglycosides: streptomycin, neomycin, gentamycin (only given IV by vet), amikacin and trobramycin. used against enteric bacteria, extremely ototoxic (damage hearing) and nephrotoxic (damage kidney. Not very used in horses except in ointments

Question 18

sulfonamide characteristics

Answer 18

some microbes need extracellular PABA to form folic acid. sulfas are structurally similar to PABA (so bacteria grab sulfa instead of PABA), sulfa reversibly blocks folic acid synthesis, bacteriostatic, not very used by itself anymore

Question 19

trimethoprim

Answer 19

generally used in conjunction with sulfamethoxazole (SMZ), works with sulfa to give a stronger reaction (synergism), sulfa and trimethoprim together are bactericidal

Question 20

how many antibacterials are generally given at one time?

Answer 20

one so they don’t prevent each other from working, which may cause endotoxemia

Question 21

fluoroquinolones (floxacins)

Answer 21

newest antibiotic, broad spectrum, generally the last drug to be used tp help prevent resistance and killing the normal flora of the horse, have great activity against gram -, useful against e. coli