1 / 17

Dr. Jyotsna Agarwal Professor, Dept. of Microbiology, King George’s Medical University

Bacterial Taxonomy. Dr. Jyotsna Agarwal Professor, Dept. of Microbiology, King George’s Medical University. What is taxonomy. Classification : Orderly arrangement and placement of bacteria based on certain characters ie. Address Nomenclature : giving Names.

wbrand
Télécharger la présentation

Dr. Jyotsna Agarwal Professor, Dept. of Microbiology, King George’s Medical University

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Bacterial Taxonomy Dr. Jyotsna Agarwal Professor, Dept. of Microbiology, King George’s Medical University

  2. What is taxonomy • Classification: Orderly arrangement and placement of bacteria based on certain characters ie. Address • Nomenclature: giving Names

  3. Families - related bacteria eg. Enterobacteriaceae • Within a family - numerous genus eg.Escherichia, Klebsiella, Salmonella • A genus contains many species eg. E. coli, E. tarda

  4. Species • Taxonomical unit • Based on morpholopgy, biochemical properties & antigenic characters • Nucleotide base ratio constant for a given species (AT : GC) • Genetic homology demonstrated by DNA hybridization > 98%

  5. Interspecies Classification They are identical, may show some differences due to mutation • Biotype - based on biochemical reactions • Serotype - based on antigens on bacteria • Phage type - susceptibility to particular phage • Colicin type - substance secreted by some bacteria • Molecular typing: Plasmid profile, DNA sequence

  6. A bacterial population derived from a single bacteria by binary fission is called CLONE • A bacterial population obtained from a particular source is called STRAIN

  7. Nomenclature • Casual name / Scientific name: eg. Gonococcus / Neisseriae gonorrhoeae Pneumococcus / Streptococcus pneumoniae • Name could be a character: Staphylococcus aureus • Place of discovery: Salmonella london • Scientist: Clostridium welchii • Disease: Clostridium tetani

  8. Bacterial Growth & Metabolism

  9. Prokaryotes • Asexual reproduction - binary fission • Generation time or doubling time • Clinical implication?

  10. Bacterial Growth Curve 4 phases

  11. What is a Bacterial colony? • Colony - visible growth on a culture plate. • Colony Forming Unit- CFU ?

  12. Bacterial Nutrition • Autotrophs - photo /chemo • Heterotrophs • Need preformed organic compounds • Includes most pathogenic bacteria • Fastidious heterotrophs

  13. Bacterial Metabolism • Help us in identifying bacteria by their end products • Help us in knowing how to inhibit bacteria

  14. Energy Generating Process • Sugars formed or obtained - broken down to release energy • Aerobic respiration • Anaerobic respiration • Fermentation • Microbes that use aerobic respiration, detoxify generated waste: Catalase: H2O2 ------- H20 and 02 Superoxide dismutase : oxygen radical ----- H20 and O2

  15. Energy Generating Process • Aerobic respiration: • COMPLETE breakdown of glucose to CO2 & H2O • Final electron receptor O2 • Yield = 38 ATP • Fermentation: • Yield = 2 ATP • Endproducts: Lactic acid/Alcohol • Final electron receptor is organic molecule • Anaerobic respiration: • Yield >2 <38 ATP • Absence of oxygen

  16. Factors affecting bacterial growth • Oxygen : Obligate /facultative; aerobes / anaerobes; microaerophilics • Temperature • Ph • Osmotic pressure • CO2

  17. Summary • Bacterial Taxonomy • Bacterial growth curve • Fastidious /non fastidious bacteria • Obligate/facultative anaerobe • Obligate aerobes

More Related