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• Clostridium botulinum


  Also known as Canned good bacillus
• Clostridium botulinum virulence factors

  • Botulinum toxin
• Botulinum toxin


  Most potent bacterial toxin known, blocks the release of acetylcholine (Ach) resulting in flaccid paralysis
• Clostridium botulinum diseases

  • Food-borne botulism
  • Wound botulism
  • Infant or intestinal botulism
• Wound botulism


  The toxin is produced in the wound, resembles food-borne illness except that the incubation period is longer (-10 days), gastrointestinal symptoms are lacking
• Infant or intestinal botulism

  Common cause of SIDS, taken from improperly processed or fresh honey, leads to lethargy and decreased muscle tone
• Clostridium botulinum laboratory indications

  • Culture specimen: food remnant or stool
  • Primary isolation media: blood agar and cooled meat medium
  • Conditions: 35C, strict anaerobiosis
  • Cultural characteristics: 2-3 mm slightly hemolytic colonies appear on blood agar, colonies appear slightly brown under transmitted light
• Clostridium botulinum biochemical tests

  • + lipase test
• Clostridium botulinum control and prevention


  • Administration of trivalent toxin
  • Adequate ventilation
  • Proper food preparation
  • Infants recover with supportive care
• Clostridium difficile virulence factors

  • Enterotoxin (toxin A)
  • Cytotoxin (toxin B)
• Enterotoxin (toxin A)


  Promotes fluid secretion and intestinal hemorrhage (like cholera toxin)
• Cytotoxin (toxin B)


  Damages mucosal membranes by depolymerizing cellular cytoskeleton
• Pseudomembranous colitis

  Usage of broad-spectrum antibiotic treatment (ex: clindamycin or ampicillin) results in suppression of normal GI floral and proliferation of C. difficile, C. difficile is usually acquired from hospital environment
• Clostridium difficile laboratory identification

  • Culture on blood agar plate: Will produce yellow green fluorescing colonies with a "horse' stable" odor
  • Culture on Cycloserine-Cefoxitin Egg Yolk Fructose Agar: Produces yellow ground glass colonies
• Clostridium perfringens virulence factors

  • α-toxin (phospholipase C or lecithinase)
  • β and iota toxin
  • θ (theta) toxin
• α-toxin (phospholipase C or lecithinase)

  Hemolytic, initiates muscle infection that may progress to gas gangrene, shows nagler reaction, also produced by C. novyi, bifermentans, some vibrios
• β and iota toxin

  Have lethal and necrotizing properties, increase capillary permeability
• θ (theta) toxin


  Hemolysin, antigenically related to streptolysin O, also known as perfringolysin O
• Clostridium perfringens diseases


  • Skin and soft tissue infection: gas gangrene or clostridial myonecrosis
  • Intestinal disorders: food poisoning, enteritis necroticans (pigbel)
• Gas gangrene or clostridial myonecrosis

  Mainly caused by C. perfringens Type A and C. septicum, C. novyi, C. histolyticum, etc., characteristic pathology: near absence of PMN's despite extensive tissue destruction, essential factor: trauma particularly deep muscle laceration, incubation period: 10 - 48h with C. perfringens, 2 - 3 days with C. septicum, 5 - 6 days with C. novyi, pain and crepitus is present, death is due to circulatory collapse
• Food poisoning


  Caused by cytotoxin which act on small bowel brush border, usually caused by cold or warmed up meat dish
• Clostridial uterine infection


  Abortion, positive in 5% women
• Clostridium perfringens pathogenesis


  1. Spores germinate - cells multiply - ferments CHO - releases gas - distention of tissue

  2. Interference with blood

  3. Release of toxins and hyaluronidase

  4. Results to the spread of infection

  5. Necrosis extends with the increase in bacterial growth

  6. Anemia, Toxemia, and Death results
• Clostridium perfringens laboratory identification

  • Microscopic: absence of its central or sub-terminal spore in artificial media or pathological tissue
  • Culture on blood agar plate: produce characteristic target colonies, double zone hemolysis or alpha prime hemolysis, reverse CAMP's test positive
  • Culture in chopped meat glucose media: abundant growth with gas formation
  • Biochemical tests: milk media - stormy fermentation, lecithinase test - lecithinase produced by C. perfringens splits lecithin (component of egg yolk) to insoluble diglycerides resulting in an opaque halo surrounding a colony growing on an egg yolk agar, Nagler or Lecithovitelline reaction - McClung or Neomycin Egg Yolk medium with C. perfringens Type A antitoxin, disappearance or reduction of the opacity on the antitoxin onhalf of the plate with antitoxin denotes neutralization of type A lecithinase and indicates a positive Nagler's test
• Peptostreptococcus


  Gram positive, anaerobic cocci in chains, common member of the normal gut flora and respiratory tract, almost always found when clinically significant in co-infections with other anaerobes and facultative anaerobes, the only genus of the gram-positive anaerobic cocci involved in disease
• Veillonella


  Gram negative, anaerobic cocci, counterpart of Neisseria, common member of the mouth and intestinal flora of humans, found in co-infections with other anaerobes and facultative anaerobes
• Propionibacterium


  Gram positive, non-space forming anaerobic bacillus, produces propionic acid, widely distributed as normal flora of skin and other body sites, including the respiratory tract, and may act as opportunistic pathogen with other copathogens, resembles Corynebacterium in morphology and cell arrangement, some strains are aerotolerant, yet yield better growth under strictly anaerobic conditions
• Propionibacterium acnes


  Most common gram-positive, non-sporeforming, anaerobic rod encountered in clinical specimens, slowly growing in culture, common resident of the pilosebaceous glands of the human skin, causative agent of acne vulgaris (pimples), in addition to acne, P. acnes has been implicated in other infections such as cornmeal ulcers, heart valves, prosthetic valves, CNS shunts, opportunistic mixed infections with other flora, highly susceptible to various B-lactam antimicrobial agents such as penicillin G
• Actinomyces israelii


  Gram-positive bacillus that tends to form branches sometimes with a beaded appearance, common member of the mouth flora of humans, aerotolerant anaerobe, very slow growing and difficult to recover in culture, responds well to long-term therapy with penicillin class of antibiotics
• Actinomyces israelii clinical syndromes

  • Cervical-facial
  • Pulmonary
  • Abdominal
  • Genitourinary
• Cervical-facial actinomycosis


  The most common cause of "lumpy jaw", slow developing abscess, chronic infection may erupt into sinus tracts on face or neck, dental surgery or facial trauma predisposition
• Pulmonary actinomycosis


  Aspiration of mouth flora to lower respiratory tract, primary pneumonia may result, radiography not specific to Actinomyces, chronic infection in which abscess is formed, abscess which can bore its way to the surface and produce sinus tracts, sulfur granules can be seen in the fluid, granules are actually aggregated microcolonies, gram smear reveals the long filamentous Actinomyces
• Abdominal actinomycosis


  Infections follows ingestion of organism, GI lesions can occur, not unlike those seen in pulmonary infection, abscess can rupture through musculature and skin to form tracts
• Genitourinary actinomycosis


  A. israelii may colonize the female genital tract as normal flora, associated with long-term use of IUD's, indistinguishable from pelvic inflammatory disease, treated with antibiotics and removal of the device
• Bacteroides fragilis


  Common member of the normal gut flora, cause serious infections if the normal GI mucosal barrier is breached, can be carried to virtually any organ of the body via blood stream, often found in co-infections with facultative anaerobes, the organism does not have a characteristic gram-negative endotoxin
• Fusobacterium spp


  Has spindle shaped morphology, found in respiratory and GI tracts, found in mixed infections
• Prevotella melaninogenica


  Regular bacillus morphology, found in respiratory and GI tracts, cause of lung and dental infections, grows a black-pigmented colony
• Porphyromonas spp


  Regular bacillus morphology, purple-pigmented bacilli on agar, found in mouth and genitourinary tract, cause of head, neck, and pleuropulmonary infections and periodontal disease
• Disease


  A pathophysiological response to internal or external factors
• Disorder


  A disruption to regular bodily structure and function