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Flashcards in microbial growth Deck (27)
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1
Q

Asepsis vs sepsis

A

asepsis: absence of significant contamination
sepsis: microbial contamination

2
Q

Sterilization

Commerical sterilization

Disinfection

Antisepsis

A

Removal of all microbial life

Kills C. Botulinum endospores

removal of pathogen

removal of pathogens from living tissue

3
Q

Degerming

Sanitization

Biocide/Germicide

Bacteriostasis

A

Removal of microbes from a limited area

Lowering the number of micrbial counts on utensils

Kills microbes

Inhibits microbes (does not kill)

4
Q

Microbial control Agent

A

Alters membrane permeability

damages proteins

damages nucleic acids

5
Q

Heat

TDP vs TDT

A

Kills by denaturing enzymes

TDP (Thermal death point): lowest temperature in which all cell culture will be killed within 10 min

TDT (Thermal death time): The time it takes the cell culture to die at a specific temperature

6
Q

Autoclave

A

121C at 15 psi

moist/heat denatures proteins

7
Q

Pasteurization

A

Reduces spoilage organisms and pathogens

Treatment: 63C for 30 minutes

High Temp for short time: 72C for 15 sec

ultra High temp: 140C for 1 sec

Except: thermoduric organisms. wil survive

8
Q

Dry Heat Sterilization

A

Kills by oxidation

  • dry heat
  • flaming
  • incineration
  • hot air sterilization

Hot air: 170C for 2 hr

Autoclave: 121C for 15 min.

9
Q

Filtration

Hepa vs membrane filtration

A

HEPA: Removes microbes > 0.3um

Membrane Filtration: Removes Microbes > 0.22um

10
Q

Microbial Control

Low temp

High Pressure

Desiccation

Osmotic Pressure

Chemicals

A

Low temperature: Inhibits microbial growth

  • Refrigeration
  • Deep Freezing
  • Lyophilization

High Pressure: Denatures proteins

Desiccation: Prevents Metabolism

Osmotic pressure: causes Plasmolysis (Shrinkage from loss of water)

Chemicals: controls growth by reducing population to safe levels on living and inanimate objects.

11
Q

Radiation

A

Ionizing radiation - damages DNA & ionizes water to release OH

  • X-rays
  • gamma rays
  • electron beams

Nonionizing radiation - Damages DNA

  • UV
  • 260nm

Microwaves - kills by heat except antimicrobial

12
Q

Disinfectants

A

Phenol & Phenolics (Carbolic acid) - Disrupt plasma membranes

Bisphenols (Hexacholorphene & Triclosan) - Disrupt plasma membranes

Biguanides (Chlorhexidine) - Disrupt plasma membranes

  • High specificity to bacterial cell membrane
  • has broad spectrum activity (Both gram - and gram + bacteria)

Halogens (Iodine & Chlorine)

Alcohol (Ethanol & Isopropanol) - Dentaures protein, dissolves lipids. Requires water

13
Q

Heavy Metals

A

Ag (Silver), Hg (Mercury) & Cu (Copper)

Silver Nitrate: Prevents gonorrheal ophthalmia neonatorum

Silver Sulfadiazine: Toopical cream used on burns

Copper sulfate: an algicide

Oligodynamic action: Denature proteins

14
Q

Surfactant

A

Soap: Degerms

Acid-anionic detergents: sanitizing

Quarternary Ammonium Compounds: bactericidal, denatures proteins & distrupts plasma membrane

15
Q

Food Preservative

A

Organic Acids (Sorbic acid, benzoic acid, calcium propionate)

  • Inhibits metabolism
  • controls mod and bacteria in food & cosmetics

Nitrite

  • Prevents endospore germination

Antibiotics (Nisin & Natamycin)

  • Prevents spoilage of cheese
16
Q

Aldehydes

A

Inactivates protein by cross linking w/ functional groups

Use: Medical Equipment

Glutaraldehyde

formaldehyde

Orthophthalaldehyde

17
Q

Gas Sterilants

A

Denatures proteins

Use: Heat-sensitive material

Ethylene oxide

18
Q

Peroxygens

A

Oxidizing agents

Use: Contaminated surfaces

19
Q

Microbial characteristics

A

most resistant to least

Prions

endospores

mycobacteria

vegetative protozoa

Gram -

Fungi

viruses w/o envelope

gram +

viruses w/ lipid envelopes

20
Q

Chemotherapy

A

Paul Ehrlich, Chemist: methylene blue for staining bacteria. Dyed rabbit ear vein

Koch: Alkaline methylene blue w/ heat to stain waxy envelope

Alexander Fleming: Discovered mold, penicillium notatum

21
Q

Anitmicrobial Drugs

A

Chemotheraphy - The use of drug to treat disease

Antimicrobial drugs: Interferes with microbial growth in host

Antibiotic: inhibits microbes using substance produced by a microbe

Selective toxicity: Kills microbes w/o damaging host

22
Q

Antimicrobial spectrum

A

Broad spectrum

Narrow spectrum

Superinfection

23
Q

Penicillin

A

Natural

Penicillin G (injection)

Penicillin V (Oral)

Semisynthetic

Oxacillin (Narrow - Gram +)

Ampicillin (Extended - many Gram -)

24
Q

Cell wall synthesis

A

1st Generation: Narrow spectrum

2nd generation: Extended spectrum

3rd Generation: includes psudeomonads

4th generation: Broadest spectrum

25
Q

Polypeptide antibiotics

A

Bacitracin (topical)

against Gram +

Vancomycin

Glycopeptide

Last Line against anitibiotic resistant S. aureus

26
Q

Antibiotic Resistance

A
  • Enzymatic destruction of drug
  • Prevention of penetration of drug
  • Alteration of drug’s target site
  • Rapid ejection of the drug
27
Q

Causes of antibiotic resistance

A
  • Using outdated or weakened antibiotics
  • Using antibiotics for the common cold and other inappropriate conditions
  • Using antibiotics in animal feed
  • Failing complete the prescribed regimen
  • Using someone else’s leftover prescription