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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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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)


Muscular spasms in an individual with tetanus (23.7)


Streptococcus pyogenes stained

with fluorescent antibody (24.2)


Streptococcus pyogenes

growing on blood agar (22.6)


Lactobacillus species (11.3)

Produce lactic acid; aerotolerant anaerobe, obligate fermenter.

Metabolizes glycogen in the vagina, low pH protects against infection


Aerobic Chemoorganotrophs

  • Obligate aerobes

  • Facultative anaerobes


Obligate Aerobes

  • Large variety of bacteria

  • Ex. Mycrococcus species

  • Ex. Mycobacterium species

  • Ex. Pseudomonas species


Micrococcus luteus (11.11)

Airborne, common contaminant in petri dishes,

recognized by yellow pigments


Pseudomonas species (11.12)

Pigmented Gram-negative rods, diverse biochemical capabilities, important in bioremediation, P. aeruginosa is a common opportunistic pathogen in hospitals


Mycobacterium tuberculosis

in sputum from a tuberculosis patient (24.17)


Stained lung

tissue showing a tubercule

(a granuloma containing

inflammatory cells) and

lung X-ray from a

tuberculosis

patient (24.18)


Facultative Anaerobes

  • Ex. Corynebacterium species

  • Ex. Enterobacteriaceae family


Corynebacterium (11.13)

Gram-positive pleomorphic rods (coryneforms)

C. diptheriae causes diphtheria


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


Thriving in Terrestrial Environments


Endospore – formers (11.15)

Gram-positive rods

Bacillus anthracis

Clostridium tetani


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


Legionella pneumophila,

stained with a fluorescent antibody (24.20)


Scanning EM of Vibrio cholerae

attached to intestinal mucosa using pili (25.12)


Mode of action of cholera toxin (25.13)


Spirochetes(11.26)


Syphilitic chancre, the entry point for

Treponema pallidum (22.12)


Scanning EM of Borrelia burgdorferi(22.13)


Life cycle of the

Deer Tick (22.16)


Animals as Habitats

  • Skin

  • Mucous membranes

  • Obligate intracellular parasites


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


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


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


Otis media

(24.8)


Meningitis is also

caused by:

Haemophilus

influenzae

Neisseria

meningitidis

Streptococcus pneumoniae in spinal fluid

from a meningococcal meningitis patient (27.4)


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


Mycoplasma pneumoniae growing on agar (11.27)


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


Coxiella(11.29)


Chlamydia (11.30)

1 = reticulate bodies, noninfectious

2-4 = dense bodies, infectious upon cell lysis


Table 11.1


Table 11.1cont


Table 11.2


Table 11.3


Table 11.3cont


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