6.3 action of antibiotics

Question 1

what is selective toxicity?

Answer 1

antimicrobial drugs interfere with the metabolism of pathogens with minimal damage to cells of the human host

Question 2

what is the most commonly used antimicrobial?

Answer 2

antibiotics

Question 3

what was the first antibiotics to be used?

Answer 3

penicillin

Question 4

why are antibiotics effective?

Answer 4

because they disrupt the biochemistry of the bacterial cells

Question 5

what are the two effects of antibiotics?

Answer 5

they can be bacteriostatic or bactericidal

Question 6

how do bacteriostatic antibiotics work?

Answer 6

they inhibit the growth/reproduction (by stopping protein synthesis) of the microorganisms and usually work for everyday infections combined witht the work of the immune system

Question 7

what is an example of a bacteriostatic antibiotic?

Answer 7

Tetracycline (protein synthesis inhibitor) which is used to treat acne, urinary tract infections and respiratory tract infections

Question 8

how do bactericidal antibiotics work?

Answer 8

destroys pathogens by interrupting their cell walls and are given for severe and dangerous infections (TB, HIV, Aids)

Question 9

what is an example of a bacteicidal antibiotic?

Answer 9

penecillins (damaged cell membrane/lysis) that are used to treat skin infections, chest infections and urinary tract infections

Question 10

how are antibiotics classified on effectiveness?

Answer 10

broad-spectrum (that kill all good and bad bacteria) or narrow spectrum (target only one or two specific pathogens)

Question 11

what factors affect the effectiveness of antimicrobial drugs?

Answer 11

• concentration of the drug in the area of the body infected
• local pH
• whether either the pathogen or the host tissue destroy the antibiotic
• the susceptibility of the pathogen to the particular antibiotic used