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Control of Microbial Growth. Gabriella Gita Febriana NIM : 10406002. Pasteur : invisible microbes could cause disease Lister : found the modern antiseptic for surgery Used a solution of carbolic acid (phenol). Introduction. Louis Pasteur. Joseph Lister. Control of Microbial Growth.

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control of microbial growth

Control of Microbial Growth

Gabriella Gita Febriana

NIM : 10406002

introduction
Control of Microbial Growth
  • Pasteur : invisible microbes could cause disease
  • Lister : found the modern antiseptic for surgery
  • Used a solution of carbolic acid (phenol)
Introduction

Louis Pasteur

Joseph Lister

control of microbial growth1
Control of Microbial GrowthControl of Microbial Growth
  • To INHIBIT or PREVENT growth of microorganisms
  • Affected in 2 basic ways :
    • By killing microorganisms (cidal agents)
    • By inhibiting the growth of microorganisms (static agents)
  • Sterilization : complete destruction or elimination of all viable microorganisms in a sterilized substance
methods of sterilization i heat
Control of Microbial GrowthMethods of SterilizationI. Heat
  • Incineration
    • Burns organisms and physically destroys them
  • Boiling
    • 100ᵒC, 30 minutes kills everything except endospores
    • Intermitent boiling (>6hours) to kill endospores
methods of sterilization i heat cont
Control of Microbial GrowthMethods of SterilizationI. Heat (cont.)
  • Autoclaving
    • Most effective and efficient
    • Usual standard temperature/pressure : 121ᵒC/15psi for 15 minutes
    • Using steam under pressure as the sterilizing agent
    • Thermal Death Time
  • Dry heat
    • Not as effective as moist heat
methods of sterilization ii irradiation
Control of Microbial GrowthMethods of SterilizationII. Irradiation
  • Ultraviolet
    • Causes adjacent thymine molecules on DNA to dimerize inhibiting DNA replication
  • Gamma Radiation
    • Break chemical bonds by interacting with the electrons of atomic constituents
    • Highly effective in killing microorganisms
methods of sterilization ii irradiation cont
Control of Microbial GrowthMethods of SterilizationII. Irradiation (cont.)
  • Electron Beam Radiation (e-beam radiation)
    • Low penetration and high dose rates.
    • Similar to Gamma radiation
methods of sterilization iii filtration
Control of Microbial GrowthMethods of SterilizationIII. Filtration
  • Exclusion of all cells in a liquid or gas
  • For sterilization of solution which would be denatured by heat. eg: antibiotics, injectable drugs, amino acids, vitamins, etc.

Millipore membrane

methods of sterilization iv gas chemicals
Control of Microbial GrowthMethods of SterilizationIV. Gas & Chemicals
  • Ethylene oxide (ETO)
    • Most commonly used form of chemical sterilization
    • Reacts with amino acids, protein, and DNA to prevent microbial reporduction
    • Used for cellulose and plastic irradiation
slide10
Control of Microbial Growth

ETO Sterilization Gas Chamber

methods of sterilization iv gas chemicals cont
Control of Microbial GrowthMethods of SterilizationIV. Gas & Chemicals (cont.)
  • Ozone Sterilization
    • Uses oxygen that is subjected to an intense electrical field that separates oxygen molecules into atomic oxygen.
    • Used as disinfectant for water and food

Ozone fogger

Ozone sterilizer

methods of sterilization iv gas chemicals cont1
Control of Microbial GrowthMethods of SterilizationIV. Gas & Chemicals (cont.)
  • Low Temperature Gas Plasma (LTGP)
    • Alternative to ethylene oxide
    • Uses small amount of hydrogen peroxide (H2O2)

energized with radio frequencies waves into gas plasma

    • Generation of free radicals destroy microorganisms
non sterilizing methods i application of heat
Control of Microbial GrowthNon Sterilizing MethodsI. Application of Heat
  • Boiling
    • Inactivates viruses
    • Giardia cysts can survive in this process
  • Pasteurization
    • Use of mild heat to reduce the number of microorganisms in products or foods. ex: milk
    • Milk 63ᵒC, 30 min (batch method) or 71ᵒC 15 sec (flash method)
  • Ultrapasteurization
    • Milk is heated to temperature of 140ᵒC
non sterilizing methods ii low temperature
Control of Microbial GrowthNon Sterilizing MethodsII. Low Temperature
  • Refrigeration & Freezing
    • non bactericidal
    • most foods are preserved against microbial growth in the household freezer
non sterilizing methods iii drying
Control of Microbial GrowthNon Sterilizing MethodsIII. Drying
  • Removal of H2O
    • often used to preserve foods
    • removal of water heat, evaporation, freeze-drying, and addition of salt or sugar
non sterilizing methods iv irradiation
Control of Microbial GrowthNon Sterilizing MethodsIV. Irradiation
  • UV, X-ray, Gamma Radiation
    • destroys microorganisms
    • fruits and vegetables are irradiated to increase their shelf life up to 500 percent
    • According to the FDA, irradiation does not make food radioactive, nor does it noticeably change taste, texture, or appearance. 
control of microbial growth by chemical agents
Control of Microbial GrowthControl of Microbial Growth by Chemical Agents
  • Antimicrobial Agents
    • chemicals that kill or inhibit the growth microorganisms
    • may be of natural or synthetic origin, and they may have a static or cidal effect on microorganisms.  
types of antimicrobial agents
Control of Microbial GrowthTypes of Antimicrobial Agents
  • Antiseptics
    • microbicidal agents harmless enough to be applied to the skin and mucous membrane
    • should not be taken internally
  • Disinfectants
    • agents that kill microorganisms, but not necessarily their spores
    • not safe for application to living tissues
    • used on inanimate objects
types of antimicrobial agents cont
Control of Microbial GrowthTypes of Antimicrobial Agents (cont.)
  • Preservatives
    • static agents used to inhibit the growth of microorganisms
    • nontoxic
types of antimicrobial agents cont1
Control of Microbial GrowthTypes of Antimicrobial Agents (cont.)
  • Chemoterapeutic Agents (synthetic antibiotics)
    • antimicrobial agents of synthetic origin useful in the treatment of microbial or viral disease
    • Ex : sulfonilamides, isoniazid, ethambutol, AZT, nalidixic acid and chloramphenicol
  • Antibiotics
    • antimicrobial agents produced by microorganisms that kill or inhibit other microorganisms
    • low molecular-weight (non-protein) molecules produced as secondary metabolites, mainly by microorganisms that live in the soil
types of antimicrobial agents cont2
Control of Microbial GrowthTypes of Antimicrobial Agents (cont.)
  • Semi-synthetic Antibiotics
    • molecules produced by a microbe that are subsequently modified by an organic chemist to enhance their antimicrobial properties
antimicrobial agents in treatment of infectious diseases
Control of Microbial GrowthAntimicrobial Agents in Treatment of Infectious Diseases
  • Selective Toxicity
    • acts in some way that inhibits or kills bacterial pathogens
    • has little or no toxic effect on the animal taking the drug
  • Spectrum of Action
    • Narrow spectrum
    • Broad spectrum
    • Limited Spectrum
mode of actions
Control of Microbial GrowthMode of Actions
  • Cell wall synthesis inhibitor
    • Beta-lactams antibiotics
    • Natural Penicillins
    • Semi-synthetic penicillins
    • Clavulanic Acid
    • Cephalosporins
    • Bacitracin
  • Cell membrane inhibitor
    • Polymyxin
mode of actions cont
Control of Microbial GrowthMode of Actions (cont.)
  • Protein synthesis inhibitor
    • Tetracyclines, e.g : tetracycline, chlortetracycline, doxycycline
    • Chloramphenicol
    • Macrolides, e.g : erythromycin, azythromycin
    • Aminoglycosides, e.g : streptomycin
    • Kanamycine
    • Gentamicin, Tobramycin
mode of actions cont1
Control of Microbial GrowthMode of Actions (cont.)
  • Effects of Nucleic Acids
    • Quinolones, e.g : nalidixic, ciprofloxacin
    • Rifamycins, e.g : rifampicin
  • Competitive inhibitors
    • Sulfonamides, e.g : sulfanilamide, gantrisin and trimethoprim
bacterial resistance to antibiotics
Control of Microbial GrowthBacterial Resistance to Antibiotics
  • Inherent (natural) resistance
  • Acquired resistance
  • Vertical evolution
  • Horizontal Gene Transmission (HGT)
    • Bacteria exchange genes by 3 process :
      • Conjugation
      • Transduction
      • Transformation
alternative to antibiotics
Control of Microbial GrowthAlternative to Antibiotics
  • Phage Therapy
    • use of lyticbacteriophages to treat pathogenic bacterial infections
    • Benefit : derived from the observation that bacteriophages are much more specific than most antibiotics that are in clinical use
    • Negative effect : phages are self-replicating in their target bacterial cella single, small dose is theoretically efficacious
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