1. Which of the following antibiotic does not inhibit bacterial
cell wall synthesis: a. benzylpenicillin
b. vancomycin
c. cephalosporins
d. ciprofloxacin
e. bacitracin
Ciprofloxacin belongs to the group of quinolone which
blocks DNA synthesis by inhibiting DNA gyrase.
..
2. Which of the following aminoglycoside is most likely to
induce allergic reaction when applied to the eye? a. amikacin
b. gentamicin
c. neomycin
d. kanamycin
e. tobramycin
Allergic conjunctivitis has been reported in about
8% of people using topical neomycin.
3. The following agent is active against Pseudomonas
EXCEPT:
a. vancomycin
e. ofloxacin
Pseudomonas is sensitive to aminoglycoside and quinolone
antibiotics.
.
4. The following is true about Staphylococcus epidermidis:
a. they appear as Gram positive cocci in chains
b. the majority are sensitive to penicillin
c. they are coagulase positive
d. they are destroyed by povodine iodine
e. any positive culture in blood agar can be ignored as they are
commensals.
They are coagulase negative which appear as Gram +ve
cocci in bunches. They are resistant to penicillin.
Although they are skin commensals, they can give rise
to infection. They are destroyed by povodine iodine.
5. Which of the following antibiotic inhibit protein synthesis
by binding to the 30S subunit of bacterial ribosomes:
a. tetracycline
b. erythromycin
c. rifampicin
d. chloramphenicol
e. sulphonamide
Erythromycin inhibits protein synthesis by binding
to a subunit of the bacterial ribosome (50S).
Rifampin inhibits RNA synthesis by inhibiting one
of the enzymes (DNA-dependent RNA polymerase)
needed in this process. RNA is needed to make
proteins.
Chloramphenicol inhibits protein synthesis by binding
to a subunit of bacterial ribosomes (50S).
Sulphonamide blocks cell metabolism by inhibiting
enzymes which are needed in the biosynthesis of
folic acid which is a necessary cell compound.