MicroPara

• Microbiology is the study of all living organisms that are too small to be seen by the naked eye
• Microbiology ultimately focuses on how to manipulate minute organisms and how they can affect our daily lives
• Branches of Microbiology by Taxonomy:

  • Bacteriology: study of bacteria
  • Virology: study of viruses
  • Mycology: deals with various fungal microorganisms (e.g. fungi, molds, yeasts)
  • Parasitology: involves unicellular and multicellular parasites
  • Immunology: study of the immune system and relationships between pathogens like bacteria and viruses and their hosts
  • Hematology: study of nematodes (roundworms)
  • Protozoology: study of protozoa, single-celled organisms like amoebae
  • Phycology: study of algae
• Branches of Microbiology by Type of Applied Microbiological Research:

  • Agricultural Microbiology: study of microorganisms that interact with plants and soils
  • Food Microbiology: study of microorganisms that spoil food or cause foodborne illnesses, and how microorganisms are used in food production (e.g. beer fermentation)
  • Medical Microbiology: study of microorganisms responsible for human diseases
  • Microbial Biotechnology: using microbes in industrial or consumer products
  • Pharmaceutical Microbiology: study of microorganisms used in pharmaceutical products like vaccines and antibiotics
• Relevance to Nursing:

  • Proper specimen handling
  • Strict compliance to sanitation procedures
  • Vaccination
  • Proper patient management
• History of Microbiology:

  • Anton van Leeuwenhoek: Father of microbiology, first to publish observations of bacteria
  • Robert Koch: Father of Modern Bacteriology, discovered anthrax disease cycle and bacteria responsible for tuberculosis and cholera, Germ Theory
  • Louis Pasteur: Discovered principles of vaccination, microbial fermentation, and pasteurization, ended the debate on Theory of Spontaneous Generation
  • Francesco Redi: Father of Modern Parasitology, proposed the theory of biogenesis
  • Robert Hooke: First used the word "cell" to name microscopic honeycomb cavities in cork
• • Jan Baptiste Evan Helmont: Supported the theory of Spontaneous Generation
  • John Needham: Accepted the Theory of Spontaneous Generation, observed microscopic creatures in boiled broth
  • Lazzaro Spallanzani: Disagreed with Needham's conclusions, questioned the Theory of Spontaneous Generation
  • Shibasaburo Kitasato: Discovered the bacterium causing bubonic plague, demonstrated the importance of antitoxin to prevent diseases like diphtheria and tetanus
• History of the classification of Microorganisms:

  • Taxonomy is the systematic classification of living organisms
  • Taxonomists:
  • Aristotle: classified living things as plants and animals
  • Carl Linnaeus: Introduced the classification system through systemic method, giving organisms a genus and species
  • Ernst Henrich Haeckel: Divided organisms into 3 different categories based on characteristics, functions, etc., introduced the 3 kingdoms Animalia, Plantae, Protista
• • Carl Woese: Introduced the three-domain system with primary kingdoms Archaebacteria, Eubacteria, Eukaryotes Protista Fungi Animalia Plantae
• Criteria used in classifying bacteria:

  • Capsule: a polysaccharide layer that completely envelopes the cell, offers protection, enhances the ability of bacterial pathogens to cause disease, and can help in attachment to surfaces

  
• Disease-causing organisms with capsules include S. Pneumoniae, B. anthracis, and Y. pestis
• Prokaryotic cells differ from eukaryotic cells in various aspects like the absence of a nucleus, membrane-bound organelles, and sterols in the plasma membrane
• Prokaryotic ribosomes are smaller in size compared to eukaryotic ribosomes
• Prokaryotic cell division occurs through binary fission, while eukaryotic cells undergo mitotic division
• Endospores are resistant asexual spores that develop inside some bacterial cells, providing high resistance to various environmental factors
• Structures within the cytoplasm of bacteria include the cytoplasm/protoplasm, nucleoid (bacterial chromosome), plasmids, ribosomes, and cytoplasmic membrane/plasma membrane
• Materials move across the bacterial cytoplasmic membrane through passive diffusion and active transport mechanisms like antiport pumps, symport pumps, and endocytosis
• A prokaryotic cell lacks a nucleus and other membrane-bound organelles

  
• Structure of a prokaryotic cell:

  • No nucleus
  • DNA in the nucleoid region
  • Cytoplasm
  • Ribosomes
  • Cell membrane
  • Cell wall
  • Flagella for movement
  • Pili for attachment
  • Capsule for protection

  
• A symporter is a protein that transports two molecules across a membrane at the same time

  
• In symport, two sodium ions and one potassium ion are transported across the membrane simultaneously
• Exocytosis is a process where a cell creates a vesicle to enclose something inside the cell, for the purpose of moving it outside of the cell, across the membrane

  
• Cytoysis occurs when a cell bursts and releases its contents into the extracellular environment due to a great influx of water into the cell
• Types of Cytoysis:

  • Endocytosis: large amounts of extracellular fluid may be taken into a cell by engulfing
  • Receptor-mediated endocytosis: recognizes a specific molecule that the cell "wants" to take in and forms a vesicle around the area where it recognizes the molecule
  • Exocytosis: the cell creates a vesicle to enclose something inside the cell, for the purpose of moving it outside of the cell, across the membrane
• Divisome is a large and highly dynamic molecular machine responsible for the process of division in bacteria
• Morphological differences in bacteria:

  • Cocci: spherical, oval, or flattened on one side
  • Bacilli: rod-shaped
  • Spirochetes: spiral in form
  • Pleomorphic: lacking distinct shape
• Metabolism in bacteria involves all the chemical reactions that occur in a cell, relying on enzymes for biochemistry
• Types of Bacteria based on metabolism:

  • Lipolytic Bacteria: hydrolyze triglycerides due to the production of extracellular lipases
  • Saccharolytic Bacteria: metabolize complex carbohydrates under aerobic and anaerobic conditions
  • Proteolytic Bacteria: produce protease enzyme
• Oxygen metabolism in bacteria:

  • Enzymes like catalase, peroxidase, and superoxide dismutase break down toxic oxygen byproducts
  • Classification based on O2 requirement: Obligate Aerobe, Facultative anaerobe, Microaerophilic anaerobe, Aerotolerant anaerobe, Obligate anaerobe
• Nutrition in bacteria:

  • Carbon and Energy Source: Phototrophs, Chemotrophs, Autotrophs, Heterotrophs, Chemoheterotrophs
  • Temperature Requirement: Psychrophilic, Mesophilic, Thermophilic, Hyperthermophilic
• Staining characteristics in bacteria:

  • Gram-positive bacteria retain crystal violet dye and stain purple or blue
  • Gram-negative bacteria stain red/pink due to a thin layer of peptidoglycan covered by an outer membrane
• Steps in Gram Staining:

  • Crystal Violet as primary stain
  • Gram's Iodine as mordant
  • Acetone Alcohol as decolorizer
  • Safranin as counterstain
• Acid-Fast Stain is used to identify acid-fast organisms like Mycobacterium and Nocardia
• Colony characteristics:

  • A colony is a visible mass of microbial cells originating from a single mother cell
  • Colonial Morphology includes shape, elevation, color, margin, etc.
• • Streptococcus pyogenes: common bacteria causing sore throat and tonsils
• Common bacteria and their associated infections/diseases:

  • Treponema pallidum: causative agent of Syphilis
  • Clostridium tetani: agent of tetanus
  • Bacillus anthracis: causative agent of anthrax disease
  • Escherichia coli: most common cause of UTI
  • Chlamydia trachomatis: causative agent of chlamydia
  • Mycobacterium leprae: causative agent of leprosy
  • Salmonella typhi: causative agent of typhoid fever
  • Candida albicans: causative agent of oral/genital thrush
  • Yersinia pestis: causative agent of plague
  • Bacillus cereus: bacteria associated with food poisoning
  • Neisseria gonorrheae: causative agent of an STI, gonorrhea
  • Streptococcus pneumoniae: bacteria causing Community Acquired Pneumonia (CAP)
  • Methicillin Resistant Staphylococcus aureus (MRSA): leading cause of Hospital Acquired Pneumonia (HAP)
  • Staphylococcus epidermidis: most frequent contaminant of blood units