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Classification Classification Presentation Transcript

  • Classification of Microbes
    • What are Microbes?
    • A microbe is any living thing that spends its life at a size visible sometimes only with a microscope.
    • It is too tiny to be seen with the naked eye. Microbes are the oldest form of life on Earth.
    • The term microbe is short for microorganism, which means small organism.
    • To help people understand the different types of microbes, they are grouped or classified in various ways.
    • Microbes are very diverse and represent all the great kingdoms of life.
  • Prokaryotes (Bacteria)
    • Eubacter "True" bacteria
      • Human pathogens
      • Clinical or environmental
      • One kingdom
    • Archaea
      • Environmental organisms
      • Second kingdom
  • Eukaryotes
    • Other cell-based life e.g.
    • Plants
    • Animals
    • Fungi
  • Prokaryotic vs. Eukaryotic Cells
    • Prokaryotic cells
      • No Nucleus
      • No Organelles
      • Cell Wall of peptidoglycan
      • Binary Fission
      • 1 circular chromosome
    • Eukaryotic Cells
      • Nucleus
      • Organelles
      • If cell wall, Cellulose or chitin
      • Mitosis
      • Linear chromosomes
    • Here is an outline of the major groups of microorganisms:
    • Viruses
    • Bacteria
    • Algae
    • Fungi
    • Protozoa
  • Bacteria
    • Bacteria consist of only one cell, but they're a very complex group of living things.
    • Some bacteria can live in temperatures above the boiling point and in cold below the freezing point.
    • There are thousands of species of bacteria, but all of them are basically one of three different shapes.
    • Some are rod- or stick-shaped; others are shaped like little balls.
    • Others still are helical or spiral in shape.
    • Some bacteria cells exist as individuals while others cluster together to form pairs, chains, squares or other groupings.
  • Classification of Microbes
    • Taxonomic Hierarchy For eg: Escherichia coli
      • Domain Bacteria
      • Kingdom Monera
      • Phylum Proteobacteria
      • Class Gammaproteobacteria
      • Order Enterobacteriales
      • Family Enterobacteriaceae
      • Genus Escherichia
      • Species E. coli
  • Classification of bacteria
    • There are several approaches to bacterial classification
    • A. Morphological classsification .
    • Based on morphology bacteria are divided into various groups
    • 1. Filamentous or higher bacteria- Actinomycetes
    • 2. True or lower bacteria
      • I. Gram positive bacilli
    • Aerobes- corynebacterium, bacillus
    • Anaerobes-Clostridium, lactobacillus
    • II. Gram positive cocci
    • III. Gram negative cocci
    • IV. Gram negative bacilli or rods
  • Gram-positive rods Gram-negative rods Gram-positive cocci Gram-negative cocci
    • V. coccobacilli- Brucella
    • 3. Comma chaped- vibrios
    • 4. Spirochaetes- Borrelia, Treponema
    • 5 . Mycoplasmas- Cell wall deficient
    • 6 . Ricketsia and chlamydia- Obligate parasites
    • B.Nutritional classification
    • I. Based on Energy requirements
    • Phototrophs: Derive energy from sunlight
    • Chemotrophs: Use Chemicals
    • II. Based on ability to synthesize essential metabolites
    • Autotrophs: Synthesize organic coumpounds from carbon dioxide and nitrogen
    • Heterotrophs: Depend on preformed organic compounds eg pathogens
    • III. Based on oxygen requirements
    • Aerobes
    • Anaerobes
  • Gram-positive cocci Anaerobic Gram-positive rods Anaerobic Gram-negative rods Anaerobic Gram-positive cocci Anaerobic Gram-negative cocci
    • IV. Based on temperature
    • Psychrophiles: Below 20°C
    • Mesophiles: 25-40°C
    • Thermophiles: 55-80°C
    • C . Biochemical classification :
    • LF
    • NLF
    • LLF
    • Production of Indole, H2S, Catalase, Oxidase, Urease etc
    • D. Classification based on staining reaction :
    • I. Based on Grams stain :
    • Gram positive bacteria
    • Gram negative bacteria
      • II. Based on acid fast stain :
    • Acid fast bacilli
    • Non acid fast bacilli
    • E. Serological/ antigenic classification
    • Microorganism possess many different kinds of antigens, based on which they are classified into
    • I. Serovars or Serotype
    • II. Sero groups
  • Major Taxonomic Groups of Bacteria per Bergey’s manual
    • Gracilicutes – gram-negative cell walls, thin-skinned
    • Firmicutes – gram-positive cell walls, thick skinned
    • Tenericutes – lack a cell wall & are soft
    • Mendosicutes – archaea, primitive procaryotes with unusual cell walls & nutritional habits
    • Assignment:
    • Find out what is Bergey’s manual i n detail.