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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
Chemoorganotrophs (fermentation) • Variety of end products (acids and gases) • Ex. Clostridium species - form endospores • Ex. Lactic acid bacteria (Lactobacillus, Streptococcus, Enterococcus)
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
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)
Syphilitic chancre, the entry point for Treponema pallidum (22.12)
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
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
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
Chlamydia (11.30) 1 = reticulate bodies, noninfectious 2-4 = dense bodies, infectious upon cell lysis