Microbiology

• Types of fermentation


  • Lactic acid, ethanol, and butyric acid
  • 2,3butanediol (intermediate acetoin, detected by Voges-Proskauer test)
  • Mixed acids (detected by methyl red test)
• Microorganisms


  Tiny living organisms that are too small to be seen with the naked eye, including bacteria, viruses, fungi, and protists
• Microorganisms are found everywhere in the environment, including in soil, water, air, and even in our own bodies
• Some microorganisms can cause diseases, while others play important roles in various processes such as decomposition, nutrient cycling, and food production
• Microorganisms are essential for life on Earth and have a wide range of applications in biotechnology, medicine, and industry
• Types of microorganisms


  • Viruses
  • Bacteria
  • Fungi
  • Protozoa
  • Algae
  • Archaea
• Virology


  The study of viruses, including their structure, function, classification, and interactions with host organisms
• Bacteriology


  The study of bacteria, including their morphology, physiology, genetics, ecology, and pathogenesis
• Mycology


  The study of fungi, including their structure, function, ecology, genetics, and evolution
• Protozoology


  The study of protists, which are single-celled eukaryotic organisms that are neither plants, animals, nor fungi
• Phycology


  The study of algae, which are a diverse group of photosynthetic organisms that range from microscopic unicellular organisms to large seaweeds
• Archaeology (not to be confused with the archaeological study of human history)


  The study of archaea, which are a domain of single-celled microorganisms that are distinct from bacteria and eukaryotes
• Viruses


  Tiny, infectious agents that can only replicate inside the living cells of other organisms, consisting of genetic material (either DNA or RNA) surrounded by a protein coat called a capsid, and sometimes a lipid envelope
• Organisms that viruses can infect

  • Bacteria (bacteriophages)
  • Plants (phytoviruses)
  • Animals (veterinary viruses)
  • Fungi (mycoviruses or mycophages)
  • Protozoa (protist viruses)
  • Humans
• Viruses cause diseases such as influenza, HIV/AIDS, Ebola, and COVID-19 in humans, and can also cause diseases in animals and plants
• How viruses work


  1. Attach to a host cell

  2. Inject their genetic material

  3. Hijack the host cell's machinery to produce more copies of the virus

  4. New virus particles burst out of the host cell and infect other cells
• While viruses are known for causing disease, they also play important roles in ecosystems and have been used in biotechnology for things like gene therapy and vaccine development
• Viruses affecting the skin (cutaneous or dermatotropic viruses)

  • Human papillomavirus (HPV)
  • Molluscum contagiosum virus
  • Herpes simplex virus (HSV)
  • Varicella-zoster virus (VZV)
  • Human T-cell lymphotropic virus (HTLV)
• Other viruses affecting humans

  • Monkeypox
  • Chickenpox
  • Measles
  • Mons
  • Rubella
  • Polio
  • Rabies
• These viruses are transmitted through various means, including direct contact with an infected individual, sexual contact, or exposure to contaminated objects and surfaces
• Viruses affecting the eye (neurotrophic viruses)

  • Herpes simplex virus (HSV)
  • Varicella-zoster virus (VZV)
  • Cytomegalovirus (CMV)
  • Adenoviruses
  • Epstein-Barr virus (EBV)
• Other viruses affecting the eye

  • Yellow fever
  • Dengue
  • Kassala fever
  • Ebola
• These viruses can be transmitted through various means, including direct contact, respiratory droplets, or exposure to contaminated objects or surfaces. Treatment depends on the specific virus and the severity of the infection
• Viruses affecting the nose (respiratory viruses)

  • Rhinoviruses
  • Influenza viruses
  • Respiratory syncytial virus (RSV)
  • Coronaviruses
• Respiratory viruses are typically transmitted through respiratory droplets or direct contact with an infected person or contaminated surfaces
• Neuropathic viruses (viruses that affect the nervous system)


  • Herpes simplex virus (HSV)
  • Varicella-zoster virus (VZV)
  • Epstein-Barr virus (EBV)
  • West Nile virus (WNV)
  • Rabies virus
• Viruses that affect the blood (hematological viruses or blood-borne viruses)

  • Human immunodeficiency virus (HIV)
  • Hepatitis B virus (HBV)
  • Hepatitis C virus (HCV)
  • Cytomegalovirus (CMV)
  • West Nile virus (WNV)
  • Lassa fever
• Gastrointestinal tract viruses (enteric viruses)

  • Norovirus
  • Rotavirus
  • Adenovirus
  • Astrovirus
  • Hepatitis A
  • Hepatitis C
• Peptidoglycan consists of alternating sugars (N-acetylglucosamine and N-acetylluramic acid) crosslinked by short polypeptide chains.
• The cell wall is composed of peptidoglycan, which provides strength to the bacterial cell.
• Peptidoglycan consists of alternating sugars (N-acetylglucosamine and N-acetyltalose) crosslinked by short polypeptide chains.
• Bacteria with thicker walls are more resistant to antibiotics that target the cell wall.
• The cell wall of bacteria is primarily composed of peptidoglycan, a unique molecule not found in other organisms.
• Sterilization


  Complete eradication of all forms of microorganisms, including bacterial spores
• Disinfection


  Killing or removing of harmful vegetative microorganisms
• Disinfectant


  Chemical substance used to achieve disinfection on inanimate surfaces
• Antiseptic


  Chemical substances that can be safely used on living tissues for sanitization
• Methods of Sterilization


  • Physical methods
  • Chemical methods
• Physical methods of sterilization

  • Heat (dry heat & moist heat)
  • U.V. Light
  • Ionizing Radiation
  • Filtration
• Chemical methods of sterilization

  • Ethylene Oxide
  • Gluteraldehyde