Microbial Growth Control 2

Question 1

TERMINOLOGIES (Chemical)

1. on living tissues to prevent infection
2. disinfect inanimate objects
3. drug/ chemical agent that kills bacteria
4. drug/ chemical agent that inhibits growth & reproduction of
   bacteria

4 variables of disinfection

Answer 1

1. Antiseptic
2. Disinfectant
3. Bactericidal
4. Bacteriostatic

concentration, time, temp, ph

Question 2

Alcohols
1. refers to two water-soluble chemical

Answer 2

Ethyl alcohol (60-95%) & Isopropyl alcohol

Question 3

ALDEHYDES

1. used as disinfectant & sterilant in both its liquid and gaseous states,
   but highly discouraged due to carcinogenic properties
   - __ formalin in water — dilute to _____ = effective
   - ____ can inactivate bacteria
2. Higgh-level disinfectant & chemical sterilant
   - germicidal
   - sporicidal

Answer 3

1. Formaldehyde
   - 37% formalin in water — dilute to 5% formaldehyde = effective
   - 0.2-0.4%
2. Glutaraldehyde
   - 2% glutaraldehyde for 10 mins
   - 2% glutaraldehyde for 3-10hrs

Question 4

Halogens
1. can be used both as antiseptics and disinfectant
- example
2. Chlorine is in the form of
- avail as liquid
- available as solid
- when chlorine mixed with water, forms
- CDC recommended
- for waterntreatkehr acc to CDC
- for water treatment acc to PNSDW

Answer 4

1. Iodophores
   - Povidone-iodine
2. Hypochlorites
   - Sodium hypochlorite
   - Calcium hypochlorite
   - hypochlorous acid
   - 1:10 dilution of 5.25% sol’n
   - 4mg/L
   - 0.3-1.5mg/L

Question 5

Detergents

1. surfactants interact w/ lipid in cell membrane & w/ surrounding water

Answer 5

Quaternary Ammonium Compounds

Question 6

Phenolics

1. membrane disruption
2. disrupts bacterial electron transport & inhibit
   membrane-bound enzymes
3. disrupt cell wall & inactivate enzyme
4. disrupt cell wall

Answer 6

1. Chlorhexidine Gluconate
2. Hexachlorophene
3. Parachlorometaxylenol
4. Triclosan

Question 7

Gaseous Disinfectant

1. for sterilization of heat-sensitive equipment; however, it is explosive
   - concentration
2. for pharmaceutical sterilization
3. used as sterilizer
   - mechanism

Answer 7

1. Ethylene Oxide
   - 450-700mg/L of chamber space at 55-600C for 2hrs
2. Periacetic acid
3. Hydrogen Peroxide
   - strong oxidizer

Question 8

Heavy metals

1. *1% for eyedrop sol’n used as prophylactic
   treatment for newborn w/ gonocoocal conjunctivitis,
2. Mechanism

Answer 8

1. Silver nitrate
2. protein inactivation

Question 9

stains used as inhibitors
1. gentian violet; gram staining
2. basic dye; against fungi & gram (+) bacteria

Answer 9

1. Crystal violet
2. Malachite green

Question 10

BIOLOGICAL INDICATORS
1. Autoclave
2. Radiation
3. Dry heat oven
4. Ethyl oxide

Answer 10

1. Bacillus stearothermophilus
2. Bacillus pumitis
3. Bacillus subtilis var. niger
4. Bacillus subtilis var. globijii

Question 11

Phenol Coefficient

= disinfectant is more effective than phenol
= disinfectant is less effective than phenol
= same effectiveness

Answer 11

> 1
<1
=1