Spore-Producing Rods
Bacillus (aerobic) and Clostridium (anaerobic)

• Bacillus anthracis is the causative agent of anthrax, which takes on cutaneous, respiratory, and gastrointestinal forms.
  – Cutaneous anthrax is the most common and least dangerous form.
  Contracted from handling animal hides or other products that carry anthrax spores; intravenous drug use can also spread cutaneous anthrax.
  Lesions tend to be on exposed areas of the body, including the face, neck, forearms, and hands. Indicate that lesions comprise a red area of edema with a central necrotic eschar.
  – Inhalation anthrax is the most lethal form of anthrax.
  Upon inhalation of the spores, the mediastinal lymph nodes enlarge; pulmonary edema occurs (which produces a bat-wing appearance on x-ray), and, respiratory failure from collapsed lung can result without effective treatment.
  – Gastrointestinal anthrax is the result of consumption of contaminated meats.
  The effects can occur throughout the GI tract, and include lesions and ulcers; patients can experience vomiting and diarrhea.

• Bacillus cereus causes food poisoning, both emetic and diarrheal forms.
  – Infection is especially associated with contaminated rice, meats, and vegetables.

• Clostridium difficile causes colitis, which is characterized by inflammation of the colon and diarrhea.
  – A pseudomembranous covering can develop on the wall of the colon. The covering, which comprises inflamed mucosa with raised yellow plaques, looks like a furry rug in gross images.
  – Colitis is associated with antibiotic use, which can kill off the normal, harmless gastrointestinal bacteria and allow for Clostridium difficile overgrowth.

• Clostridium perfringens can cause soft tissue infections, including myocystis, cellulitis, and myonecrosis.
  – Myonecrosis, which is also called gas gangrene, is characterized by areas of necrosis that produce gaseous bubbles in the tissues.
  – Clostridium perfringens can also cause food poisoning.

• Clostridium tetani, which can be found in the soil, causes tetanus.
  – Tetanus is characterized by spastic paralysis; show that this can produce the characteristic extension of the head, neck, and spine, called opistotonos.

• Clostridium botulinum causes botulism; the bacteria can be found in canned goods, and is the reason that infants under one year of age should not be given honey (by childhood, most individuals are resistant to the pathogen in honey).
  – Botulism is characterized by descending flaccid paralysis and respiratory failure.

Non-Spore-Producing Rods

• Corynebacterium diphtheriae
  – The Diphtheria toxin gene is introduced to the bacteria via a bacteriophage.
  – Respiratory diphtheria is characterized by a sore throat with a firmly adhered pseudomembranous covering.
  Serious complications can arise, including airway obstruction, myocarditis, and cranial neuropathies.

• Listeria monocytogenes causes listeriosis.
  – Individuals become infected when they ingest contaminated foods, most often deli meats or cheeses (this is why pregnant women are advised to avoid these foods).
  – The effects of listeriosis depend on the health and age of the individual:
  In healthy, non-pregnant adults, infection can cause flu-like symptoms with watery diarrhea.
  Immunocompromised adults are at increased risk of meningitis.
  Neonates fare the worst, with the possibility of death, organ damage, or meningitis.