G+ bacilli

• Gram + Bacilli


  • Spore forming
  • Non- Spore forming
• Gram + Bacilli - Spore forming

  • Clostridium
  • Bacillus anthracis
• Gram + Bacilli - Non-Spore forming


  • Mycobacterium
  • Corynebacterium
  • Bacillus cereus
  • Listeria
• Spore Forming Bacilli


  • Bacillus enjoys oxygen (aerobic)
  • Clostridium multiply in an anaerobic environment
• Bacillus anthracis spore


  Very stable, resistant to drying, heat, UV light, & disinfectants, can survive dormant in soil for decades
• Bacillus anthracis spore is used for biological terrorism and warfare
• Bacillus anthracis was used by the Japanese army in Manchuria in 1940
• Bacillus anthracis


  • Causes anthrax, a disease that primarily affects herbivores (cows and sheep)
  • Humans are exposed to spores during direct contact with infected animals or soil, or when handling infected animal products, such as hides or wool
  • Cases from contact with goat hair products from Haiti, such as drums or rugs
• Cutaneous anthrax infection


  1. Potent exotoxin causes localized tissue necrosis, evidenced by a painless round black lesion with a rim of edema (malignant pustule)

  2. Skin lesion resolves spontaneously in 80-90% of cases

  3. Mortality rate = 20%
• Pulmonary anthrax | Woolsorter's disease


  1. Spores are taken up by WBCs in the lungs

  2. Mediastinal hemorrhage & pleural effusions

  3. Mortality rate = 90%
• Gastrointestinal anthrax


  1. Ingestion of spores from contaminated meat

  2. B. anthracis matures and replicates in intestine, where exotoxin is released

  3. Vomiting, abdominal pain, and bloody diarrhea

  4. Necrotic lesion within the intestine

  5. Mortality rate = 100%
• Bacillus anthracis Exotoxins


  • Edema Factor (EF)
  • Protective antigen (PA)
  • Lethal Factor (LF)
• Clostridium species


  • C. tetani
  • C. botulinum
  • C. perfringens
  • C. difficile
• Clostridium species


  • Gram positive bacilli
  • Spore-formers
  • Anaerobic
  • Catalase negative
• Clostridium tetani spores


  Commonly found in soil and animal feces
• Tetanospasmin


  Exotoxin released by Clostridium tetani that causes a sustained contraction of skeletal muscles called tetany
• Tetanus


  1. Follows a puncture wound or skin trauma by any object contaminated with Clostridium tetani spores in anaerobic environment

  2. Causes severe muscle spasms of jaw (trismus, lockjaw), grotesque grinning expression (risus sardonicus) due to spasm of facial muscle, severe hyperextension (opisthotonus)

  3. Mortality is high once lock jaw has been reached
• Tetanus treatment in the ER

  1. Patients with last shot >10 years ago: Give booster

  2. Unimmunized patients: Give immune globulin + booster

  3. Patients who already developed tetanus: 1) Neutralize circulating toxin with human tetanus immune globulins, 2) Give an immunization booster, 3) Clean the wound, 4) Antibiotics, 5) Provide intensive supportive therapy until the toxin is cleared
• Clostridium perfringens - Gas gangrene


  1. Spores contaminate wounds from battle or other trauma

  2. Deep wounds with lots of dead tissue create an anaerobic environment that offers an excellent home for Clostridium perfringens

  3. Cellulitis/wound infection: Necrotic skin is exposed to Clostridium perfringens, which grows and damages local tissue. Palpation reveals a moist, spongy, crackling consistency to the skin due to pockets of gas (crepitus)

  4. Clostridial myonecrosis: trauma into muscle, secretes exotoxins that destroy adjacent muscle. CT scan reveals pockets of gas within the muscles and subcutaneous tissue. As the enzymes degrade the muscles, a thin, blackish fluid exudes from the skin.
• Clostridium difficile - Pseudomembranous Enterocolitis

  1. Follows the use of broad spectrum antibiotics (such as ampicillin, clindamycin, and cephalosporins)

  2. Antibiotics can wipe out part of normal intestinal flora, allowing pathogenic Clostridium difficile to superinfect the colon

  3. Toxin A causes diarrhea, and Toxin B is cytotoxic to colonic cells

  4. Disease is characterized by severe diarrhea, abdominal cramping, and fever
• Clostridium species - Other Names

  • C. tetani - "Drumstick Bacillus", "Tennis Racket Bacillus", "Lollipop Bacillus", "Tack Head Bacillus"
  • C. botulinum - "Canned good Bacillus"
  • C. difficile - "Difficult to treat"
  • C. perfringens - "Welch Bacillus" (William Welch), "Gas Gangrene Bacillus"
• Clostridium species - Toxins

  • C. tetani - Tetanospasmin (neurotoxin)
  • C. botulinum - Botulinum toxin / Botulinal toxin / Botox (neurotoxin)
  • C. difficile - Toxin A (enterotoxin), Toxin B (cytotoxin)
  • C. perfringens - Alpha toxin, Beta toxin
• Clostridium species - Diseases

  • C. tetani - Tetanus (Rigid paralysis)
  • C. botulinum - Botulism (Flaccid paralysis - Adult, Infant)
  • C. difficile - Pseudomembranous enterocolitis (Antibiotic-associated)
  • C. perfringens - Crepitus, Gas gangrene / Myonecrosis