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30 Cards in this Set
- Front
- Back
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Anaerbores: Gram Positive
Sporeforming rods |
Clostridium spp.
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Anaerbores: Gram Positive
Nonsporefordming rods |
Actinomyces spp.
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Anaerbores: Gram Positive
Cocci (2) |
Peptococcus and Peptostreptococcus spp.
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Anaerbores: Gram Positive
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Clostridium spp.
Actinomyces spp. Peptococcus and Peptostreptococcus spp. |
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Anaerbores: Gram Negative
Non-sporeforming |
Bacteroides-like group
Fusobacterium spp. |
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Anaerbores: Gram Negative
Cocci |
Veilonella spp.
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Anaerbores: Gram Negative
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Bacteroides-like group
Fusobacterium spp. Veilonella spp. |
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Non-Clostridal Infections Characteristics
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Anaerobic
Lozalized infection Abcess forms anywhere in body -- but not connected to blood supply Polymicrobic often -- mix of faculative and anaerobic bacteria Highly resistant strains due to carrying resistant plasmids (so many gut bacteria they pass these around) Very difficult to treat for above reasons -- surgery to drain abcess plus multiple antibiotics Low virulence Can be Fatal Slow growing, fastidious (picky target, req. nutrient rich env), produce fermentation smelly gases |
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Bacteroides:
Aero/anaero? Gram? Shape? Normal/Patho? |
Anaerobes -- Most important nonclostridial type
Gram-neg Rods Found as normal flora in the Colon, Vagina, and Mouth (not skin) |
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Porphyromonas and Prevotella
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Bile-sensitive Bacteroide-like spp.
LPS have endotoxic properties (vs. other bacteroides) |
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Virulence of Bacteroides
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Make proteases that help them spread in tissue
LPS is NOT endotoxic Some have antiphagocytotic capsule (B. fragilis, P. melaninogenica) Don't make entertoxins except for B. fragilis |
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Entry of Bacteroides?
Where? Req. for growth? Contagious? |
Breech epithelia via surgery, wounds.
Endogenous infections near gut. Require LOW TISSUE REDOX for growth in addition to entry. Not contagious. |
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Bacteroides fragilis:
found where? causes what diseases? epidemiology? exceptional how? |
Found in colon.
Abdominal infections with 2 stages: peritonitis leading to abscess formations B. fragilis -- only .5% of colonic flora but account for many infections in abdomen or bloodstream Only bacteroides to make entertoxins |
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Prevotella bivia:
found where? causes what diseases? |
Found in female genital tract
Pelvic Inflammatory disease and infertility |
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Prevotella melaninogenica
found where? causes what diseases? |
Found in mouth
Respiratory tract infections (dental, sinusitis, pulmonary) |
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Porphyromonas gingivalis
found where? causes what diseases? |
Found in mouth
Respiratory tract infections (dental, sinusitis, pulmonary) |
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Histotoxic Clostridia
ana/aer? gram? spores? rods? found where? |
Gram positive
Anaerobic Spore-forming Rods Found as normal flora in GI and in soil all over world |
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Histotoxic Clostrdia:
Virulence factors Entry |
Exotoxins (protein toxins made and secreted outside the cell)
Either endo: spores or exogenous infectious: wounds etc. Require low tissue redox for growth |
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C. perfringes -- epi? disases?
C. septicum -- diseases? |
Most common/important Histotoxic Clostridia - 90% -- C. perfinges type A food poisoning is due to enterotoxin
infections associated with cancer of GI tract |
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alpha toxin
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exotoxin of C. perfringes
a lecithinase (phospholipase C activity) that disrupts mammalian plasma membranes |
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Diseases caused by histotoxic clostridia
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Gas Gangrene
Organ infections (uterine -- illegal abortions) Septicemia/bacteremias (generalized infections) Food poisoning (C. perfringes) |
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Gas Gangrene:
Pathology Treatment |
clostridial myonecrosis: bacteria present in muscle (low redox) --> toxins kill cells to form necrotic tissue (even lower redox) --> progressive spread of infections
into circulation/distant organs. Rapidly fatal w/o treatment Treatment: very difficult -- 1. remove infected tissue by surgery, amputate 2. hyperbaric O2 (?) 3. Prevention much better: keep wounds clean |
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Endospores -- most resistant life form
Formed by what 2 types of pathogens? Form in response to? |
1. Bacillus -- aerobic/faculative
2. Clostridium -- anaerobic In response to a poor environment -- a survival response NOT reproductive |
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Endospores resistant to:
Why? |
Heat, radiation, chemicals (disinfectants), drying
Low internal water Therefore lack metabolism so can last 100 years before germinating into cell Rich in DNA stabilizing proteins so resistant to heat |
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Disease due to Spores
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Anthrax
Tetanus Infections causes by histotoxic clostridia Clostridium difficile |
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Tetanus
Name of bug -- gram/spores?/ana or aer/shape. Found where? |
Clostridium tetani -- found in soils throughout world
Gram-positive Sporeforming anaerobic rod |
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C. tetani: Virulence/Lethality?
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Tetanus neurotoxin: inhibits release of inhibitory neurotransmitters resulting in uncontrolled muscle contractions.
Extremely lethal!!!! |
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C. tetani: Entry
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Implantation of spores at a wound or during childbirth via contaminated umbilical stump
Requires low redox for spore to germinate into new cell and make neurotoxin Incubation time up to months even |
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Tetanus Disease:
How's toxin spread/work What muscles effected? What kills? |
Spreads from wound (where its produced) along nerves migrating to CNS, CNS, CNS
Toxins blocks inhibit NT release resuling in constant m. stimulation Convulsive muscle contractions of voluntary muscles of: Jaw = trismus/lockjaw Back Extremities Death from respiratory failure |
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Tetanus Disease:
Treatment Prevention Incidence |
Very difficult to treat
Give antitoxin, muscle relaxants and assisted ventilation Prevention with immunization via tetanus toxoid; disease itself does not confer immunity Still occurs in developing world esp. infants due to unimmunized mothers contaminating umbilical stump Still occurs in USA due to elderly not getting recent booster of tetanus toxoid (every 10 years) |
