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03-22-12 Medically important bacteria

03-22-12 Medically important bacteria. Chemoorganotrophs (fermentation). Variety of end products (acids and gases) Ex. Clostridium species - form endospores Ex. Lactic acid bacteria ( Lactobacillus, Streptococcus, Enterococcus). Clostridium tetani (23.8).

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03-22-12 Medically important bacteria

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  1. 03-22-12 Medically important bacteria

  2. Chemoorganotrophs (fermentation) • Variety of end products (acids and gases) • Ex. Clostridium species - form endospores • Ex. Lactic acid bacteria (Lactobacillus, Streptococcus, Enterococcus)

  3. Clostridium tetani(23.8)

  4. Muscular spasms in an individual with tetanus (23.7)

  5. Streptococcus pyogenes stained with fluorescent antibody (24.2)

  6. Streptococcus pyogenes growing on blood agar (22.6)

  7. Lactobacillus species (11.3) Produce lactic acid; aerotolerant anaerobe, obligate fermenter. Metabolizes glycogen in the vagina, low pH protects against infection

  8. Aerobic Chemoorganotrophs • Obligate aerobes • Facultative anaerobes

  9. Obligate Aerobes • Large variety of bacteria • Ex. Mycrococcus species • Ex. Mycobacterium species • Ex. Pseudomonas species

  10. Micrococcus luteus (11.11) Airborne, common contaminant in petri dishes, recognized by yellow pigments

  11. Pseudomonas species (11.12) Pigmented Gram-negative rods, diverse biochemical capabilities, important in bioremediation, P. aeruginosa is a common opportunistic pathogen in hospitals

  12. Mycobacterium tuberculosis in sputum from a tuberculosis patient (24.17)

  13. Stained lung tissue showing a tubercule (a granuloma containing inflammatory cells) and lung X-ray from a tuberculosis patient (24.18)

  14. Facultative Anaerobes • Ex. Corynebacterium species • Ex. Enterobacteriaceae family

  15. Corynebacterium (11.13) Gram-positive pleomorphic rods (coryneforms) C. diptheriae causes diphtheria

  16. Enterobacteriaceae (11.14) E. coli O157:H7 in uncooked burgers caused gastroenteritis epidemic in Washington State in 1993 Enterobacteria, Gram-negative rods, reside in intestinal tract Enterobacter, Klebsiella, Proteus are part ofnormal flora, Shigella, Salmonella, some E. coli stains, Yersina pestis cause disease

  17. Thriving in Terrestrial Environments

  18. Endospore – formers (11.15) Gram-positive rods Bacillus anthracis Clostridium tetani

  19. Aquatic Bacteria Vibrio cholerae - cholera Vibrio parahaemolyticus - gastrointestinal disease Legionella pneumophila - Legionaire’s disease Gram-negative aerobes that use aa’s Leptospira interrogans - leptospirosis Treponema pallidum – syphilis Borrelia burgdorferi - Lyme disease

  20. Legionella pneumophila, stained with a fluorescent antibody (24.20)

  21. Scanning EM of Vibrio cholerae attached to intestinal mucosa using pili (25.12)

  22. Mode of action of cholera toxin (25.13)

  23. Spirochetes(11.26)

  24. Syphilitic chancre, the entry point for Treponema pallidum (22.12)

  25. Scanning EM of Borrelia burgdorferi(22.13)

  26. Life cycle of the Deer Tick (22.16)

  27. Animals as Habitats • Skin • Mucous membranes • Obligate intracellular parasites

  28. Skin • Ex. Staphylococcus aureus. Gram-positive cocci, catalase positive, causes wound infections, food poisoning • Ex. Staphylococcus epidermidis (normal flora) Can cause disease in individuals with other medical problems

  29. Staphylococcal toxic shock in the U.S. (25.6)

  30. Mucous Membrane • Ex. Bacteroides.Anaerobic, Gram-negative rods and coccobacilli, 30% of bacteria in feces • Ex. Bifidobacterium. Anaerobic, Gram-positive rods, common intestinal flora in breast fed infants, may provide protective function • Ex. Campylobacter and Helicobacter. Gram-negative rods, microaerophiles, C. jejuni causes diarrhea in humans Helicobacter pylori causes stomach ulcers • Ex. Haemophilus. Small, Gram-negative coccobacilli, love blood, H. influenzae causes ear infections, respiratory infections and meningitis in children

  31. Otis media (24.8)

  32. Meningitis is also caused by: Haemophilus influenzae Neisseria meningitidis Streptococcus pneumoniae in spinal fluid from a meningococcal meningitis patient (27.4)

  33. Mucous Membrane • Ex. Neisseria. Gram-negative diplococci, grow on mucous membranes, N. gonorrhoeae causes gonorrhea, N. meningitidis causes menengitis • Ex. Mycoplasma. No cell wall, small pleiomorphic cells, M. pneumoniae causes “walking pneumonia” • Ex. Treponema and Borrelia. Spirochetes, T. pallidium causes syphillis, Borrelia species cause Lyme Disease, relapsing fever

  34. Mycoplasma pneumoniae growing on agar (11.27)

  35. Obligate Intracellular Parasites • Cannot reproduce outside a host cell • Transferred by blood-sucking arthropods eg Rickettsia rickettsii causes Rock Mountain Spotted Fever • Can form a sporelike structure (Ex. Coxiella) Q fever • Person to person transmission (Ex. Chlamydia) C. trachomatis causes eye infection, gonorrhea-like STD

  36. Coxiella(11.29)

  37. Chlamydia (11.30) 1 = reticulate bodies, noninfectious 2-4 = dense bodies, infectious upon cell lysis

  38. Table 11.1

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