Micropara

• Antibiotics are substances produced by microorganisms that act against other microorganisms
• Antimicrobials refer to all agents that act against microbial organisms, including bacteria (antibacterial), viruses (antiviral), fungi (antifungal), and protozoa (antiprotozoal)
• Broad spectrum antibiotics act against a larger group of bacteria, like Tetracyclines, Phenicols, Fluoroquinolones, and "Third generation and Fourth generation" Cephalosporins
• Characteristics of antibiotics include being able to kill or inhibit microbial growth, having a broad spectrum of activity, not causing harm to the patient, remaining stable when stored, remaining in specific body tissues long enough to be effective, preventing mutation and resistance, and exhibiting selective toxicity
• Antibiotics may be classified based on their spectrum of activity as broad or narrow spectrum antibiotics
• Antibiotics can also be classified based on their mode of action, such as those that interfere with the synthesis of the bacterial cell wall, alter the function of permeability of the cell membrane, inhibit protein synthesis, or act on nucleic acids
• Agents that inhibit DNA topoisomerases are essential to DNA synthesis and are critical enzymes involved in protein translation and cell replication
• DNA gyrase, a type II topoisomerase found only in prokaryotic organisms, is essential for their survival
• Quinolones have been found to be most effective against DNA gyrase, with newer generations like fluoroquinolones having a wider spectrum of activity
• Trimethoprim and sulfonamides interfere with folic acid metabolism, acting as competitive inhibitors of tetrahydrofolic acid important in DNA, RNA, and bacterial cell wall protein synthesis
• Bacteria develop resistance through innate (intrinsic) resistance, which is encoded in the chromosome of the organism and shared by all strains of the species
• Acquired resistance arises from the ability of an organism to resist an antimicrobial drug to which the species is naturally susceptible, developed due to constant exposure to the antimicrobial agent involved
• Factors contributing to antimicrobial resistance include overuse of broad-spectrum antibiotics, incorrect diagnosis, unnecessary prescription of antibiotics, and indiscriminate or improper use of antibiotics by patients
• Transformation is the simplest form of genetic exchange where free microbial DNA inserts itself into the DNA of the same species
• Transduction is the transfer of genetic material by a bacteriophage
• Conjugation is the transfer of genetic material through the sex pilus, with resistance genes carried by an extrachromosomal DNA called plasmid
• Mechanisms of drug resistance include drug modification or inactivation, prevention of cellular uptake or efflux, modification of target sites, overproduction or bypass of target enzyme, and target mimicry
• Techniques for controlling pathogenic microorganisms:

  • Heating (Moist Heat & Dry Heat)
  • Desiccation
  • Freezing
  • Filtration
  • Radiation
  • Sonic and Ultrasonic Vibrations
  • Osmotic Pressure
• Physical methods of sterilization:

  1. Heating (Moist Heat & Dry Heat)

  • Fire and boiling water have been used for sterilization and disinfection since ancient times
  • Types of heat: moist and dry heat may be applied
• Moist Heat - Temperature below 100 degrees Celsius:

  • Pasteurization
  • Vaccine Bath
  • Serum Bath
  • Inspissation
• Moist Heat - Pasteurization:

  • Many substances, such as milk, are treated with controlled heating at temperatures well below boiling point
  • Milk can be pasteurized in two ways: Flash pasteurization (HTST) and Ultrahigh-temperature (UHT) sterilization
• Moist Heat - Vaccine Bath:

  • Used to destroy contaminating bacteria in vaccine preparations
  • Heated in a water bath at 60°C for one hour daily for several successive days
  • Only vegetative forms of the bacteria are destroyed
• Moist Heat - Inspissation:

  • Used to solidify and disinfect egg-containing and serum-containing bacteria
  • Heated at 80-85°C for 30 minutes for three successive days
  • On the first day, vegetative forms will die
• Conditions influencing the effectiveness of antimicrobial agent activity:

  1. Population size

  2. Population composition

  3. Concentration or intensity of an antimicrobial agent

  4. Duration of exposure

  5. Temperature

  6. Local environment
• Population size:

  • A larger population requires a longer time to die than a smaller one
• Population composition:

  • The effectiveness of an agent varies greatly with the nature of the organisms
  • Some species are able to withstand adverse conditions better than others
• Concentration or intensity of an antimicrobial agent:

  • Often, the more concentrated a chemical agent or intense a physical agent, the more rapidly organisms are destroyed
  • Sometimes an agent is more effective at lower concentrations
• Duration of exposure:

  • The longer a population is exposed to a microbial agent, the more organisms are killed
  • Chemical antimicrobials and radiation treatments are more effective with longer exposure
• Temperature:

  • An increase in the temperature at which a chemical acts often enhances its activity
  • Lower concentrations of disinfectant can be used at higher temperatures
• Local environment:

  • The population to be controlled is surrounded by environmental factors that may offer protection or aid in its destruction
  • For example, heat kills more readily at an acid pH
• Definition of Terms:

  1. Sterilization

  2. Sterilant

  3. Disinfection

  4. Disinfectant

  5. Sanitation

  6. Antisepsis

  7. Antiseptic

  8. Germicide

  9. Bactericide

  10. Bacteriostatic
• Sterilization:

  • Is the process by which all living cells, viable spores, viruses, and viroids are either destroyed or removed from an object or habitat
  • Achieved by physical and chemical means
• Disinfection:

  • Is the killing, inhibition, or removal of microorganisms that may cause disease
  • Disinfectants are agents used to carry out disinfection
• Germicide:

  • Kill pathogens but not necessarily endospores
  • Can be particularly effective against a specific group, e.g., bactericide, fungicide, algaecide, or viricide
• How to determine if microorganisms are dead:

  • A bacterium is defined as dead if it does not grow and reproduce when inoculated into culture medium
  • An inactive virus cannot infect a suitable host
• Attachment:

  • A strong reciprocal emotional bond between an infant and a primary caregiver
  • Schaffer and Emerson's 1964 study aimed to identify stages of attachment and patterns in its development
• Freud's superego:

  • The moral component of the psyche, representing internalized societal values and standards
• Physical processes in glaciated upland landscapes:

  • Include erosion, transport, deposition, weathering, and mass movement
  • Glacial erosion involves abrasion and plucking
• Abrasion erosion:

  • A sandpapering effect caused by small rocks embedded within a glacier rubbing on bedrock
  • Leaves a smooth surface with scratches called striations
• Plucking erosion:

  • Meltwater from glaciers freeze around broken or cracked rock, breaking it off from the bedrock or sides as the ice moves down the slope
  • Most prominent when there are many joints in the rock