chapter 20

define drug resistance. how is it produced/ what measures can be taken to reduce drug resistance

Drug resistance is the lack of susceptibility of a microorganism to a chemotherapeutic agent. Drug resistance may develop when microorganisms are constantly exposed to an antimicrobial agent. Ways to minimize the development of drug-resistant microorganisms include judicious use of antimicrobial agents; following directions on the prescription; or administering two or more drugs simultaneously

This microorganism is not susceptible to antibiotics or neuromuscular blocks, but it is susceptible to protease inhibitor

Human immunodeficiency virus

The most selective antimicrobial activity would be exhibited by a drug that

Inhibits cell wall synthesis

Why does a cell die from the following antimicrobial actions? Colistimethate binds to phospholipids

Like polymyxin B, causes leaks in the plasma membrane

order of toughness

PRIONS BACILLUS CEREUS psuedomonas aeruginosa

why is it easier to kill bacteria vs worms

Selective toxicity human closely related to worms

List the advantages of using two chemotherapeutic agents simultaneously to treat a disease. What problem can be encountered using two drugs?

Simultaneous use of two agents can prevent the development of resistant strains of microorganisms, take advantage of the synergistic effect, provide therapy until a diagnosis is made, and lessen the toxicity of individual drugs by reducing the dosage of each in combination. One problem that can result from simultaneous use of two agents is the antagonistic effect

A patient with streptococcal sore throat takes penicillin for two days of a prescribed 10 day regimen. Because he feels better, he then saves the remaining penicillin for some other time. After three more days, he suffers a relapse of the sore throat. Discuss the probable cause of the relapse.

Studies that it takes time for an antibiotic to completely get rid of a pathogen. With strep 10 ten days is the usual time needed. After two days (with this patient) all of the beta strep were not destroyed. Another possibility is that there were penicillin resistant bacteria present.

cell membrane damage causes death because

cell contents leak out

an antimicrobial agent should meet al of the folowing criteria except

production of hypersensitivities in host

Vancomycin-resistant Enterococcus faecalis was isolated from a foot infection of a 40-year old man. The patient had a chronic diabetes-related foot ulcer and underwent amputation of a gangrenous toe. He subsequently developed methicillin-resistant Staphylococcus aureus bacteremia. The infection was treated with vancomycin. One week later, he developed a vancomycin-resistant S. aureus (VRSA) infection. This is the first case of VRSA in the U.S. What is the most likely source of the VRSA?

staphylococcus aureus

evolution of drug resistance requires;

variability in the popuation Not all individuals survive those most adapted to the environment survive