Control of microganism pt 2

Question 1

Chemicals work by a variety of modes of action
how?

Answer 1

Plasma membrane, nucleic acids, proteins

Question 2

how is anti microbial activity measured/

Answer 2

measured by determining the Minimum Inhibitory Concentration (MIC) – the smallest amount of agent needed to inhibit growth

Question 3

waht does sterlisation mean?

Answer 3

: Destruction of all microbes & viruses from an object. Sterile = absence of all viable organisms

Question 4

what does disinfection mean

Answer 4

Destruction of most microbes & viruses on non-living surfaces

Question 5

example of disinfection solutuion

Answer 5

Alcohols (60-85%) (ethanol, isopropanol)

Question 6

what are some factors influecning disinfectants

Answer 6

Temperature – longer to sterilise population at lower temp than at higher temp
Contact time – longer exposure time compensates for heat treatment

Question 7

what does antispsis mean

Answer 7

Reduction in number of microbes & viruses (particularly pathogens) on living tissue

Question 8

an example of antisepsis

Answer 8

Alcohol
Iodine

Question 9

what is selective toxcity

Answer 9

ability to inhibit pathogens without adversely affecting host

Question 10

how can antimicrobial drugs be used?

Answer 10

Can be used internally (antiseptics, disinfectants & sterilants too toxic)

Question 11

what is the mode of action of antmicorbial drugs

Answer 11

Function by interrupting specific microbial biosynthetic pathways

Cell wall synthesis (prevent peptidoglycan cross-linking) – e.g. vancomycin, carbapenems

Ribosome (protein synthesis) – e.g. macrolides, tetracyclines, nitrofurans

Nucleoid (DNA & RNA synthesis) – e.g. rifampin
Plasma membrane – polymyxins & daptomycin

Question 12

what are the Two categories of antimicrobial drugs:

Answer 12

Synthetic (chemotherapeutic) drugs
Antibiotics

Question 13

what are Synthetic (chemotherapeutic) drugs

Answer 13

synthetic chemical compounds that inhibit or kill microbes

Question 14

what are antibiotics

Answer 14

naturally occurring chemical compounds produced by microbes that inhibit or kill other microbes

Question 15

Antibiotics - β-Lactams

Answer 15

Low host toxicity, all have β-Lactam ring structure

Question 16

Synthetic (chemotherapeutic) drugs

Answer 16

Growth factor analogs – synthetic metabolic inhibitors. Structurally similar to growth factors but don’t function in the cell

Question 17

why is selecgive toxcity sometimes hard

Answer 17

toxicity hard to achieve as viral structures & function are so integrated into the functions of the host cell

Question 18

why does the potency many antiviral agents reduce ot

Answer 18

due to emergence of drug-resistant viruses

Question 19

why does antimicropbial resistance increase?

Answer 19

Prescriptions in unwarranted cases
Patient non-compliance (stop course when ‘feel better’)

Question 20

how can AB resistance be reduced

Answer 20

Drugs used only for treatment of susceptible diseases
Physician & patient education

Question 21

what is biological control?

Answer 21

the use of a population of one organism to reduce the population of another organism

Question 22

what are bacteriophages

Answer 22

viruses that infect bacteria but not mammalian cells

Specificity for particular bacterial species

Question 23

what is protozoa

Answer 23

Predation of bacteria by protozoa controls populations

Question 24

what are probiotcs

Answer 24

‘Good’ bacteria that can compete with pathogens & displace disease organisms from tissues