MDL 237

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MDL 237

• Clinical Bacteriology
• Spring 06
• Rhoads

2
Introduction - summary

• Characteristics of bacteria (vs Eukaryotes)
• Distinguishing bacteria via 1.
  anatomy/morphology
• 2. physiology
• Relationships with other critters on planet Earth
• Bacterial virulence pathogenicity
• --------------------------------------------------
  ------------------------------
• I hope to give you the opportunity to learn more
  this semester. Thats more for your money! Good
  news!
• Note Take good notes on this presentation. If I
  say you dont need to know it then you dont need
  to know it, but

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Bacteria vs the other guys

• Kingdom Prokaryotae (Monera)
• Prokaryotes cyanobacteria (blue-green algae)
• archae
• bacteria here is our focus
• Note facts in the next 2 slides are sometimes
  used to state differences in prokaryotes (vs
  eukaryotes) and other times to distinguish
  bacteria from everybody else. The latter is not
  really proper, but since we are only interested
  in bacteria we will do this.

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Bacteria vs the other guys

• no life cycle vegetative cells
• endospores (maybe) Clostridium, etc.
• small 0.1 10uM range, but.
• binary fission simple rapid exponential
  growth
• harder to stop / kill? bacteriastatic vs
  bacteriacidal
• simple intracellular organization no organelles
• proximity of mRNA to ribosomes
• more is better? simple harder to stop /
  kill?
• disadvantages?
• organization of DNA
• DSCCC haploid chromosome plus plasmids
• VS
• multiple linear diploid chromosomeS
  cont.

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Bacteria vs the other guys

• envelope
• cell wall composed of peptidoglycan
• exceptions Mycoplasma,Mycobacterium,etc.
• membrane(s) cytoplasmic and maybe another
• Gram stain Gram () vs Gram (-)
• other differences
• nucleic acid homology
• ribosome size / structure
• huge metabolic diversity!!!
• others that I cant think of at the moment or is
  not worth discussing

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Distinguishing bacteria anatomy / morphology

• Morphology is very important in classification,
  characterization identification of bacteria
• 1. colony morphology
• 2. cellular moropholgy
• 3. Gram stain not really morphology, but it is
  a 1st step
• 1. Colony morphology
• what is a colony?
• how do you go about seeing a colony?
• what is growth media? what are the types?
• what are the basic differences in colony
  appearance?
• can colonial morphology differ based upon the
  medium, culture conditions, age, other?
  cont.

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Streak plate for isolation isolated colonies
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No, you dont need to know this for me
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Distinguishing bacteria anatomy / morphology

• 2. Cellular morphology
• a) size Chlamydia (0.3uM) vs Bacillus (5uM)
  
• b) shape
• rod varies a lot! see 2 slides ?
• other spirochetes type of rod? see 1
  slide
• cocci round round is round, but. see 1
  slide
• c) arrangement chains see cocci slide
• clusters
• other

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Rod shape variations
Bacillus cereus with endospores
Escherichia coli
Pseudomonas aeruginosa
fusiform, ex Fusobacterium
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spirochaete, ex Borrelia Trepomena
Coryneform rod club-shaped ex Corynebacterium
spirillum, ex Helicobacter
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coccobacillus, Ex Haemophilus
Curved or comma-shaped, ex Vibrio
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clusters, ex Staphylococcus
chains, ex Streptococcus
diplococci, ex Neisseria
Streptococcus - notice the shape round?
Cocci
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Arrangement - rods
Singles pairs most rods
Corynebacterium L shaped from snapping

palisade or Chinese letters
notice polyphosphate (volutin) granules
Chains - Bacillus