Module 7 - Microbial Growth Control

Question 1

Biocide

Answer 1

all antimicrobial agents that can be used to control microbes

Question 2

• unable to produce offspring

- process by which all living cells, spores, and acellular entities are destroyed or removed

Answer 2

sterilization

Question 3

killing, inhibition, or removal of microorganisms that may cause disease.

Answer 3

disinfection

Question 4

are agents, usually chemical, used to carry out disinfection and normally used only on inanimate objects

Answer 4

disinfectant

Question 5

the microbial population is reduced to levels that are considered safe by public health standards.

Answer 5

sanitization

Question 6

it is the prevention of infection or sepsis.

Answer 6

antisepsis

Question 7

are chemical agents applied to tissue to prevent infection by killing or inhibiting pathogen growth

Answer 7

antiseptics

Question 8

kill or inhibit the growth of microorganisms within host tissue

Answer 8

chemotheraphy

Question 9

a suffix that means kills or inhibit the growth of microorganisms

Answer 9

-cide

Question 10

a suffix that means do not kill but prevent growth

Answer 10

-static

Question 11

A microbial cell is often defined as dead if __________that would normally support its growth.

Answer 11

if it does not grow when inoculated into culture medium

Question 12

types of mechanical agents

Answer 12

depth filters and membrane filters for air and liquids

Question 13

consist of fibrous or granular materials

Answer 13

depth filters

Question 14

porous membranes, a little over 0.1 mm thick, made of cellulose acetate, cellulose nitrate, polycarbonate, polyvinylidene fluoride, or other synthetic material

Answer 14

membrane filters

Question 15

two common examples of air filters

Answer 15

n95 mask and HEPA filters

Question 16

masks exclude 95% of particles that are larger than 0.3 μm

Answer 16

n95 mask

Question 17

(a type of depth filter made from fiberglass) remove 99.97% of particles 0.3 μm or larger by both physical retention and electrostatic interactions.

Answer 17

HEPA

Question 18

two types of physical control method

Answer 18

heat and radiation

Question 19

must be carried out at temperatures above 100°C, and this requires the use of saturated steam under pressure

Answer 19

moist heat

Question 20

does not sterilize, but it does kill pathogens and drastically slows spoilage by reducing the level of nonpathogenic spoilage microorganisms.

Answer 20

pasteurization

Question 21

• Intermittent sterilization

- uses steam (30–60 minutes) to destroy vegetative bacteria

Answer 21

tyndallization

Question 22

• Less effective than moist heat

- slow and not suitable for heat-sensitive materials such as plastic and rubber items.

Answer 22

dry heat

Question 23

required temperature for moist heat

Answer 23

121 degrees in celsius

Question 24

required temperature for dry heat

Answer 24

160 degrees in celsius

Question 25

-thymine dimerization of DNA, preventing replication and transcription

Answer 25

UV radiation

Question 26

excellent sterilizing agent that penetrates deep into objects.

Answer 26

ionizing radiation

Question 27

Chemicals can be employed for ________

Answer 27

sterilization, disinfection, antisepsis

Question 28

- first widely used antiseptic and disinfectant - denature proteins and disrupt cell membranes - tuberculocidal, effective in the presence of organic material, and remain active on surfaces long after application.

Answer 28

phenolics

Question 29

- most widely used disinfectants, antiseptics, and sanitizers - e bactericidal and fungicidal but not sporicidal

Answer 29

alcohols

Question 30

The two most popular alcohol germicides

Answer 30

ethanol and isopropanol

Question 31

- used as a skin antiseptic - They are used in hospitals for cleansing preoperative skin and in hospitals and laboratories for disinfecting. Some popular brands are Wescodyne for skin and laboratory disinfection, and Betadine for wounds.

Answer 31

iodine

Question 32

usual disinfectant for municipal water supplies and swimming pools

Answer 32

chlorine

Question 33

Two important eukaryotic pathogens are not killed by chlorine

Answer 33

Cryptosporidium and Giardia (both are microbes of diarrhea)

Question 34

- are organic cleansing agents that are amphipathic, having both polar hydrophilic and nonpolar hydrophobic components. - Their antimicrobial activity is the result of their ability to disrupt microbial membranes; they may also denature proteins.

Answer 34

detergents

Question 35

highly reactive molecules that inactivate nucleic acids and proteins

Answer 35

aldehydes

Question 36

Ethylene oxide is both____

Answer 36

microbicidal and sporicidal

Question 37

Potency of a disinfectant is compared to that of phenol | Useful for screening but may be misleading

Answer 37

phenol coefficiency test

Question 38

Developed concept of selective toxicity | Identified dyes that effectively treated African sleeping sickness

Answer 38

Paul Ehrlich

Question 39

identified arsenic compounds that effectively treated syphilis

Answer 39

Sahachiro Hato

Question 40

Discovered sulfonamines and sulfa drugs

Answer 40

Gerhard Domagk, and Jacques and Therese Trefouel

Question 41

First discovered by Ernest Duchesne (1896), but discovery lost Accidentally discovered by Alexander Fleming (1928) • observed penicillin activity on contaminated plate • did not think could be developed further Effectiveness demonstrated by Florey, Chain, and Heatley (1939)

Answer 41

penicillin

Question 42

an antibiotic active against tuberculosis,

Answer 42

streptomycin

Question 43

ability of drug to kill or inhibit pathogen while damaging host as little as possible

Answer 43

selective toxicity

Question 44

drug level required for clinical treatment

Answer 44

therapeutic dose

Question 45

drug level at which drug becomes too toxic

Answer 45

toxic dose

Question 46

ratio of toxic dose to therapeutic dose

Answer 46

therapeutic index

Question 47

Undesirable effects of drugs on host cells

Answer 47

side effects

Question 48

Attack only a few different pathogen

Answer 48

narrow-spectrum drugs

Question 49

Attack many different pathogens

Answer 49

broad spectrum drugs

Question 50

Lowest concentration of drug that inhibits growth of pathogens

Answer 50

minimal inhibitory concentration

Question 51

Lowest concentration of drug that kills pathogen

Answer 51

minimal lethal concentration

Question 52

Determining the level of Antimicrobial Activity

Answer 52

1. Dilution susceptibility tests for MIC 2. Disk diffusion tests – Kirby Bauer 3. The E-test MIC and diffusion

Question 53

Antibacterial Drugs | works as:

Answer 53

1. Inhibitors of cell wall synthesis 2. Protein synthesis inhibitors 3. Metabolic antagonists 4. Nucleic acid synthesis inhibition

Question 54

topical and oral disrupt membrane permeability and inhibit sterol synthesis disrupts mitotic spindle; may inhibit protein and DNA synthesis

Answer 54

superficial mycoses (fungal infections of the skin, hair, and nail)

Question 55

``` Difficult to control and can be fatal: Three (3) common drugs • Amphotericin B - binds sterols in membranes • 5-flucytosine – disrupts RNA function • Fluconazole - low side effects, used prophylactically ```

Answer 55

systemic mycoses (fungal infections affecting internal organs

Question 56

Amantidine

Answer 56

Used to prevent influenza infections | Blocks penetration and uncoating of influenza virus

Question 57

Adenine arabinoside (vidarabine)

Answer 57

Inhibits herpes virus enzymes involved in DNA and RNA synthesis and function

Question 58

Tamiflu

Answer 58

Anti-influenza agent A neuraminidase inhibitor Not a cure for influenza, but has been shown to shorten course of illness

Question 59

Acyclovir

Answer 59

Inhibits herpes virus DNA polymerase

Question 60

Valacyclovir

Answer 60

Prodrug form of acyclovir

Question 61

Ganciclovir

Answer 61

Anti-herpesvirus drugs

Question 62

foscarnet

Answer 62

Inhibits herpes virus DNA polymerase

Question 63

Anti-HIV drugs work as:

Answer 63

Reverse transcriptase (RT) inhibitors Protease inhibitors Fusion inhibitors

Question 64

Evaluation of Antimicrobial Agent Effectiveness

Answer 64

1. Department of Environment and Natural Resources (DENR) 2. Food and Drug Administration 3. Department of Agriculture 4. Department of Health

Question 65

Overcoming Drug Resistance

Answer 65

1. Give drug in appropriate concentrations to destroy susceptible 2. Give two or more drugs at same time 3. Use drugs only when necessary 4. Possible future solutions • continued development of new drugs • use of bacteriophages to treat bacterial disease