BACTERIOLOGY

• Eukaryotes


  Protista, Animalia, Plantae, Fungi
• Characteristics of Prokaryotes


  • Single circular chromosome
  • Nucleoid
  • Plasmid
  • 70s ribosomes
  • Rotating flagella and gliding
  • Pili

  
• Characteristics of Eukaryotes


  • Paired linear chromosomes
  • Nucleus
  • Nucleolus
  • Mitochondria
  • Chloroplast
  • 80s ribosomes
  • Undulating flagella and cilia

  
• Bacteria are unicellular, have no nucleus, most have peptidoglycan cell wall, divide by binary fission, and can use a wide range of chemical substances for nutrition
• Bacterial Structure


  • Cell envelope
  • Cytoplasmic components
  • External structures
  • Inclusions

  
• Cell envelope


  Cell wall and underlying cytoplasmic membrane
• Cell wall


  Provides protection and resistance to lysis, imparts shape, mostly made of peptidoglycan, has associated autolysins
• Cytoplasmic membrane


  Physical and metabolic barrier, location of electron transport system
• Cytoplasmic components


  • Cytoplasm
  • Genome
  • Ribosomes
  • Storage granules

  
• Cytoplasm


  Viscous aqueous suspension containing enzymes and storage granules
• Genome


  • Bacterial chromosome, a lipoprotein molecule containing DNA
  • Plasmid, a small self-replicating portion of DNA
• Ribosomes


  Complex globular structures composed of RNA and proteins, centers for protein synthesis, 70S

  
• External structures


  • Flagella
  • Capsule
  • Pili
• Flagella


  Long filamentous appendages used for locomotion, composed of flagellin protein
• Capsule


  Gelatinous substance made of polysaccharide and/or polypeptide, protects from phagocytosis and enables adherence
• Pili


  • Hair-like protein fibers covering the cell surface, used for adherence (common pili)
  • Involved in bacterial conjugation (sex pili)
• Inclusions


  • Metachromatic granules
  • Endospores
• Metachromatic granules


  Reserve of inorganic phosphate that can be used in ATP synthesis
• Endospores


  Resting structures formed by some bacteria for survival during adverse conditions, made of calcium dipicolinate
• Generation time


  Time for bacteria to double in size and split into two
• Bacterial replication


  Binary fission
• Major bacterial shapes


  • Bacillus (rod)
  • Coccus (spherical)
  • Spirillus (spiral)
  • Vibrio (curved)
  • Spirillum (corkscrew with flagella)
  • Spirochete (coiled spring without flagella)

  
• Cocci grouping arrangements


  • Diplococci
  • Staphylococci
  • Streptococci
  • Tetrads
  • Sarcinae
• Bacilli grouping arrangements


  • Diplobacilli
  • Streptobacilli
  • C. diphtheriae (Chinese character)
  • M. leprae (parallel character)
• Prokaryotic domains


  • Archaea
  • Bacteria
• Firmicutes


  • Clostridium
  • Bacillus
  • Staphylococcus
• Clostridium


  Obligate anaerobic, endospore-forming rods, includes pathogenic species like C. tetani, C. botulinum, C. perfringens, C. difficile
• Bacillus


  Obligate aerobic, endospore-forming rods, some species produce antibiotics and insecticides, includes pathogenic B. anthracis and B. cereus
• Staphylococcus


  Occurs in grape-like clusters, facultative aerobes, most important is S. aureus with virulence factors like protein A, coagulase, exotoxins
• Staphylococcus saprophyticus is non-hemolytic, coagulase negative, novobiocin resistant and causes "honeymoon cystitis"
• Staphylococcus epidermidis is novobiocin sensitive and has the ability to adhere to artificial materials in the body

  
• Pathogenic species


  • Staphylococcus aureus
• Staphylococcus aureus


  • Most important specie in this group
  • Facultative aerobes
  • Can survive at high osmotic pressure and low moisture (nostrils and on skin)
• Staphylococcus aureus Virulence Factors (Disable our immune responses)

  • Protein A
  • Coagulase
  • Hemolysin
  • Leukocidin
  • Penicillinase (Beta lactamase)
• Staphylococcus aureus Penetrate through tissues

  • Hyaluronidase
  • Staphylokinase
  • Lipase
  • Protease
• Staphylococcus aureus Exotoxins


  • Exfoliatin Toxins
  • Enterotoxins
  • Toxic Shock Syndrome Toxins
• Diseases by exotoxin release

  • Gastroenteritis
  • Toxic shock syndrome
  • Scalded skin syndrome
• Direct Organ Invasion


  • Skin infections
  • Acute bacterial endocarditis
  • Urinary tract infection
• Staphylococcus saprophyticus


  • Non-hemolytic
  • Coagulase negative
  • Novobiocin resistant
  • Causes "honeymoon cystitis"
• Staphylococcus epidermidis


  • Novobiocin sensitive
  • Has the ability to adhere to artificial materials in the body (e.g. catheters and prosthetic heart valves)
  • Frequently isolated in infected indwelling catheters: Prosthetic Heart Valve Endocarditis