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Bacteria classification

Bacteria classification. Or exactly how do we tell them apart?. Classification: Shape. Spherical (Round). Rod Shaped. Vibrio (comma shaped). Spirillum (spiral shaped). Classification: Gram Negative or Positive. Ability to retain certain dyes or stains

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Bacteria classification

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  1. Bacteria classification Or exactly how do we tell them apart?

  2. Classification: Shape Spherical (Round) Rod Shaped

  3. Vibrio (comma shaped) Spirillum (spiral shaped)

  4. Classification: Gram Negative or Positive Ability to retain certain dyes or stains • The bacteria picks up the dye or not depending on the chemical composition of the cell wall • Gram negatives bacteria cell wall contains Lipoproteins • Gram positive bacteria cell wall does not contain Lipoprotiens

  5. Gram Staining • A purple dye is applied to the bacteria • Washed off with a decolorizer • A red counter stain is then applied

  6. Gram Staining: Gram negative Gram negative (lose the purple colour and pick up the red) Where do these live? Example e-coli Escherichia coli Escherichia coli

  7. Gram Staining: Gram Positive Gram positive (picks up and retain the purple colour) • Where do these live? staphylococci Streptococcus

  8. Gram Negative & Positive

  9. Ability to grow in the presence of O2 or absence or both • Aerobes: grow in presence of O2 • Anaerobic: grow in the absence of O2 • Facultative: can grow in either this is can be a problem why? • Staphylococci has developed the ability to do this which now means that MRSA has become more of a concern

  10. Coccus (Plural Cocci) 3 types Staphylococci Grapelike clusters (staphylococci found on skin) Causes boils, abscesses, food poisoning, pneumonia ( gram +) Staphylococcus aureus

  11. Diplococci • Pairs of cocci • Can be gram- or gram+ • Causative agent for gonorrhea (gram-) and some forms of meningitis Neisseria gonorrhoeae.

  12. Streptococci • grows in chains not clusters: • Causative agent for Strep throat, pneumonia & rheumatic fever (gram +)

  13. Bacilli Rod-shaped bacteria • Responsible for gastroenteritis (gram -) • Tuberculosis (acid-fast: stain that adheres to a waxy cell wall) • Pneumonia, • Pertussis (Whooping cough gram -) • Botulism (gram +) • tetanus Pertussis

  14. Spirilla Spiral shaped • Syphilis • Lyme disease (vector transmission) • Due to the waxy coating on the bacterium gram stain not used Syphilis-causing bacterium Treponema palladiums,

  15. Taking a specimen Swab is taken from • Wound • Throat • Discharge Blood is taken from a vein or line Body Fluids such as • Sputum • Urine • Fecal

  16. Labeled and Transported Labels require: What do you think is needed on the label

  17. Examination • Wet mount • Liquid keeps the organisms alive and mobile so they can be examined • Smear • Specimen is spread thinly and unevenly across the slide and may be fixed

  18. Culture medium • Allows for the growth of colonies • Requires a culture medium (nutrients), warmth (incubator), organism from the swab and time

  19. Culture’s sensitivity to Antibiotics • C and S (culture and sensitivity) • Which antibiotic will work? • Why is this important?

  20. THE SUPERBUGS: Nosocomial • MRSA • CA-MRSA • VRE • C.difficle • CRE

  21. Methicillin-Resistant Staphylococcus aureus • Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium responsible for several difficult-to-treat infections in humans. • MRSA is, by definition, any strain of Staphylococcus aureus that has developed resistance to beta-lactam antibiotics which include the penicillins (methicillin, dicloxacillin, nafcillin, oxacillin, etc.) and the cephalosporins.

  22. MRSA verses CA-MRSA • MRSA (Methicillin-Resistant Staphylococcus aureus) is a nosocomial infection which means? As bacteria evolves it can develop additional attributes and MRSA is no exception • CA-MRSA: Community Acquired MRSA. • Why is this an issue?

  23. Vancomycin-resistant Enterococcus • Vancomycin-resistantEnterococcus, or vancomycin-resistant enterococci (VRE), are bacterial strains of the genus Enterococcus that are resistant to the antibioticvancomycin. To become VRE, vancomycin-sensitive enterococci typically obtain new DNA in the form of plasmids or transposons which encode genes that confer vancomycin resistance.

  24. Clostridium difficile • Clostridia are anaerobic, spore-forming rods (bacilli).[2]C. difficile is the most serious cause of antibiotic-associated diarrhoea (AAD) and can lead to pseudomembranous colitis, a severe infection of the colon, often resulting from eradication of the normal gut flora by antibiotics • Gram positive

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