IC7

• Microorganisms can be categorized as acellular or cellular, including viruses, prions, prokaryotes, and eukaryotes
• Types of bacteria based on morphology, Gram staining, acid-fast staining, and oxygen requirements
• Atypical bacteria such as Rickettsia, Chlamydia, and Mycoplasma
• Endospores and fungi, including Zygomycetes, Ascomycetes, Deuteromycetes, and Basidomycetes
• Antimicrobial resistance (AMR) is a global threat
• Significance of antimicrobial susceptibility testing (AST) parameters for antimicrobial drug effectiveness
• Antimicrobial susceptibility testing (AST) parameters

  • Minimum inhibitory concentration (MIC)
  • Spectrum of activity
• Minimum inhibitory concentration (MIC)

  • Lowest concentration of a drug that prevents visible growth of a bacteria or fungi
  • Determines the effectiveness of antimicrobial drugs against specific microorganisms
• Narrow spectrum antimicrobial


  • Targets only specific subsets of pathogenic bacteria
• Broad spectrum antimicrobial


  • Targets wide variety of pathogenic bacteria
• Spectrum of activity


  Identifies the spectrum of activity --> therapeutic dosage determination
• Sub-MIC or sub-lethal concentration

  • Useful for using the least drug concentration for the desired outcome
  • Cost effective and low toxicity
• Antibiotic targets


  • Cell wall
  • Nucleic acid synthesis
  • Plasma membrane
  • Ribosomes
  • Metabolic pathways
• AST results (MIC numbers)

  • MIC is below breakpoint = susceptible
  • MIC is between susceptible and resistant breakpoints = intermediate
  • MIC is above established breakpoint = Resistant
• Breakpoint


  • Defines susceptibility and resistance to antibacterials
  • Determined by CLSI
• Antibiotic or antimicrobial resistance


  Causes serious mortalities to regions all over the world
• Factors contributing to antibiotic or antimicrobial resistance

  • Overuse and misuse of antibiotics in therapeutic use
  • Overuse and misuse of antibiotics in agriculture and rearing of livestock
  • Overuse and misuse of antibiotics due to leakage from pharma companies
  • Inappropriate use of antibiotics
  • Sub-therapeutic dosing
  • Patient's non-compliance with the recommended course of treatment
• Mechanisms of antibiotic resistance

  • Enzymatic drug inactivation
  • Alteration of the target sites
  • Prevention of antibiotics access to target sites
• Microbial death curve or survivor plots

  Measures microbial levels after exposure to sterilization methods either by calculating the death rates (death curve) or survival rates (survival plots)
• Biological indicators (BI)


  Confirms successful sterilization process
• Disinfection


  Reducing or destroying microbial load of an inanimate substrate
• Sanitization


  Reduces microbial load of an inanimate substrates to safe public health levels
• Sterilization


  Complete elimination of all vegetative cells, endospores and viruses from an inanimate substrate
• Methods of sterilization


  • Terminal sterilization
  • Non-terminal sterilization
• Terminal sterilization methods


  • Physical - Heat (Steam, Dry heat)
  • Physical - Radiation (Electromagnetic, Particulate, Accelerated electron)
  • Chemical - Gaseous (Ethylene oxide, Low temperature steam formaldehyde, Gas plasma)
  • Chemical - Liquid (Aldehydes, Peracetic acid, Hydrogen peroxide)
• Filtration


  • For thermolabile solutions like ophthalmic solutions, antibiotics, vaccines, liquid vitamins, enzymes, culture media
  • Uses membrane filters to physically sieve out microorganism
• All pharmaceutical preparations, medical products and devices should be sterile to prevent adverse events