Control of microbial growth
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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 Growth

Control 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 Growth

Methods 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 Growth

Methods 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 Growth

Methods 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 Growth

Methods 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 Growth

Methods 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 Growth

Methods 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


Control of microbial growth

Control of Microbial Growth

ETO Sterilization Gas Chamber


Methods of sterilization iv gas chemicals cont

Control of Microbial Growth

Methods 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 Growth

Methods 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 Growth

Non 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 Growth

Non 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 Growth

Non 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 Growth

Non 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 Growth

Control 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 Growth

Types 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


Control of microbial growth

Control of Microbial Growth


Control of microbial growth

Control of Microbial Growth


Types of antimicrobial agents cont

Control of Microbial Growth

Types of Antimicrobial Agents (cont.)

  • Preservatives

    • static agents used to inhibit the growth of microorganisms

    • nontoxic


Control of microbial growth

Control of Microbial Growth


Types of antimicrobial agents cont1

Control of Microbial Growth

Types 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 Growth

Types 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


Control of microbial growth

Control of Microbial Growth


Control of microbial growth

Control of Microbial Growth


Control of microbial growth

Control of Microbial Growth


Antimicrobial agents in treatment of infectious diseases

Control of Microbial Growth

Antimicrobial 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 Growth

Mode 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 Growth

Mode 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 Growth

Mode 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 Growth

Bacterial 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 Growth

Alternative 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


Control of microbial growth

Control of Microbial Growth

THANK YOU


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