Diffusion and dilution tests that expose pathogens to antimicrobials are designed to ___________
- determine the spectrum of action of a drug
- determine which drug is most effective against a particular pahogen
- determine the amount of a drug to use against a particular pahogen
- both b and c
d. Both b and c
In the Kirby-Bauer susceptibility test, the presence of a zone of inhibition around disks containing antimicrobial agents indicates ______
- that the microbe does not grow in the presence of the agents
- that the microbe grows well in the presence of the agents
- the smallest amount of the agent that will inhibit the growth of microbe
- the minimum amount of an agent that kills the microbe in question
a. that the microbe does not grow in the presence of the agents
The key to succesful chemotherapy is
- selective toxicity
- a diffusion test
- the minimum inhibitory concentration test
- the spectrum of action
a. selective toxicity
Which of the following statements is relevant in explaining why sulfonamides are effective?
- sulfonamides attach to sterol lipids in the pathogen, disrupt the membranes, and lyse the cells
- sufonamides prevent the incoporation of amino acids into polypeptide chains
- humans and microbes use PABA differently in their metabolism
- sulfonamides inhibit DNA replication in both pathogens and human cells
c. humans and microbes use PABA differently in their metabolism
Cross resistance is _____________
- the deactivation of an antimicrobial agent by a bacterial enzyme.
- alteration of the resistant cells so that an antimicrobial agent cannot attach
- the mutation of genes that affect the cytoplasmic membrane channels so that antimicrobial agents cannot cross into the cells interior
- resistance to one antimicrobial agent because of its similarity to another antimicrobial agent
d. resistance to one antimicrobial agent because of its similarity to another microbial agent
Multiple drug resistance microbes ___________
- are resistant to all antimicrobial agents
- respond to new antimicrobials by developing resistance
- frequently develop in hospitals
- all of the above
c. frequently develop in hospitals
Which of the following is most closely associated with a beta-lactam ring?
Drugs that act against protein synthesis include ___________
- beta - lactams
Which of the following statements is false concerning antiviral drugs?
- macrolide drugs block attachment sites on teh host cell wall and prevent viruses from entering
- drugs that neutralize the acidbity of phagolysosomes prevent viral uncoating
- nucleotide analogs can be used to stop microbial replication
- drugs containing protease inhibitors retard viral growth by blocking the production of essential viral proteins
a. macrolide drugs block attachment sites of the host cell wall and prevent viruses form entering
PABA is ___________.
- a substrate used in the production of penicillin
- a type of beta-lactamase
- molecularly similar to cephalosporins
- used to synthesize folic acid
d. used to synthesize folic acid
AIDS is treated with a "cocktail" of several antiviral agents at once. Why is the cocktail more effective than a single agent? What is a physician trying to prevent by prescribing several drugs at once?
How does penicilluim escape the effects of the penicillin it secretes?
In an issue of News of the Lepidopterists' Society, a recommendation was made to moth and butterly collectors to use antimicrobials to combat disease in the young of these insects. What are the possible ramifications for human health of such usage of antimicrobials?