CONTROL OF MICROBIAL GROWTH

Sterilization

-total destruction of all organism such as cells, viable spores, viruses

Disinfection

-removal from non living objects by physical/ chemical methods

Sepsis

-it is the growth of pathogens in living tissues (indicates a diseases process/ contamination)

Asepsis

-free of pathogens or the absence of significant contamination

Bacteriostasis

-it is the inhibition of microbial growth/multiplication
example: refrigeration, freeze-drying

-destruction of disease causing microbes
-blocking the sources, routes, and vectors of transmission of disease agents
-improvement of body defenses and host resistance

Ways of controlling sources of infection

-presence of organic matter
-length of time applied
-concentration
-temperature
-nature and number of microorganism present

Factors that influence effectiveness of antimicrobial procedures

Filtration
Scrubbing
Sedimentation

Physical agents of sterilization (mechanical methods)

its cellulose membrane, asbestos, HEPA filter (high efficiency particular air fi

-it is the use of heat
-practical, inexpensive, and effective

Physical Agents

Thermal Death Point

it is the lowest temperature that will kill all organism within specified period of time

Thermal Death Time

length of time that will kill a pure culture at a specified temperature

Boiling
Steam
Pressurized steam
Autoclave

Moist Heat Sterilization

100 degrees Celsius (10-30 minutes)

Boiling

70 degrees Celsius (10 minutes)

Steam

-it is steam under pressure

Pressurized Steam

121 degrees Celsius (20 minutes 15 PSI)

Autoclave

Pasteurization

-it is mild heating to destroy microbes found in milk, beer, wine (63 degrees for 30 minutes)

High Temperature Short Time (HTST)
Ultra High Temperature (UHT)

Modern Techniques

72 degrees celsius for 15 seconds

HTST

140 degrees celsius for 2-3 seconds

UHT

Flaming, Burning, Incineration
Hot air sterilization/ dry heat baking

Types of Dry Heat Sterilization

Flaming, Burning, Incineration

it is used for contaminated disposable materials/ needle

Hot air sterilization/ dry heat baking

-it uses an oven and is used for glasswares, surgical insturments or any material destroyed in presence of water like oil

protein oxidation
slow
high temperature
more destructive
less efficient

Dry heat sterilization

protein coagulation
much faster
low temperature
less destructive
more efficient

Moist heat sterilization

Antiseptic

it is used in association with a living body/ tissue

Disinfectant

it is used together with a non-living object (lysol, muriatic acid)

Injury to cell membrane (soaps and detergents)
Inactivation of enzymes (alcohol and phenol)
Damage to the genetic material (aldehydes)

Actions of Disinfectants

Surface active compound

soap

Heavy metal compound

methiolate, silver nitrate

Alcohol and aldehyde

ethyl alcohol

Silver Nitrate

treatment for gonococcal conjunctivitis and warts

Phenol
Halogen compounds
Acids
Oxidizing agents

Chemical Disinfectants

Antibiotics

it is chemical substances produced by microorganism that inhibit growth of other organism

Chemotherapeutic Agents

it refers to synthetic and other antimicrobial agents including those agents active against human cells such as the anti cancer drugs

Spectrum of activity

-refers to the range of antimicrobial activity

Broad Spectrum

it affects wide range of organism (chloramphenicol)

Narrow Spectrum

it affects a limited range of organism (nystatin)

Inhibits cell wall synthesis
Inhibits protein synthesis
inhibits nucleic acid or rna synthesis
disruption of cell membrane function

Mechanism of action

beta lactam group (peniccilin)
glycopeptides (vancomycin)

it inhibits cell wall synthesis

aminoglycosides
tetracyclines
Chloramphenicol
macrolides

it inhibits protein synthesis

rifampin (urine orange)
qiunolones

it inhibits nucleic acid synthesis

polymyxins

disruption of cell membranes

Bacteriostratic

erythromycin

Bactericidal

vancomycin

hypersensitivity
-skin rash, fever, lymph node enlargement
-toxicity
-Otoxicity, nephro

side effects of antibiotic therapy