Bacteria have a variety of weapons that they can use to invade the human body. Some have enzymes which help them escape from the immune system, while others are part of the normal flora, just waiting for the opportunity to invade. Some can survive in tissues that have only small amounts of oxygen, while others have spores or toxins.They have different weapons, but the goal is the same--invasion.
Listeria Monocytogenes
This is a gram positive rod bacterium. Microbiologists classify bacteria with the use of a stain process they call a gram stain. L. monocytogenes is referred to as gram positive because it holds onto the first stain used in that gram staining process. "Rod" refers to its rod shape. George Brooks, M.D., Professor of Laboratory Medicine and Microbiology and Immunology at the University of California explains in "Jawetz, Melnick, & Adelberg's Medical Microbiology," that Listeria has an enzyme called listeriolysin O, which it uses to escape from being destroyed. It causes listeriosis, with either no symptoms or some diarrhea if you are healthy. Pregnant women can develop septicemia (bacteria in the bloodstream). Newborn babies can develop sepsis and meningitis. It causes septicemia and meningitis in people with impaired immune systems.
Actinomyces Israelii
According to Joseph Lentino, M.D., Ph.D., Professor of Medicine at the Loyola University Stritch School of Medicine, Actinomyces is one of the normal inhabitants of the teeth, tonsils and gums. Like Listeria, it is also a gram positive rod, but this bacterium invades tissues that have little oxygen. Thus, it can invade any tissue, including bone. It causes abscesses in the face and brain, and infections in the abdomen and uterus.
Clostridium Botulinum
Another gram positive rod, Clostridium has spores that can survive in the soil, dust, and in canned meats and vegetables that have not been sterilized long enough. It produces a toxin, which can be inactivated by simply boiling the food for several minutes. If the toxin is still active, it is absorbed in the stomach and goes through the bloodstream to reach the peripheral nerves (the nerves outside of the brain and spinal cord). Once there, it stops the nerves from releasing acetylcholine, a substance sent by the nerves to the muscles, and causes paralysis. This is one type of botulism. In infant botulism, Clostridium grows in the baby's stomach and makes the toxin in the stomach. There is a risk that honey is contaminated with Clostridium, which is why infants should never be given honey. In "Review of Medical Microbiology and Immunology," Warren Levinson, M.D., Ph.D., Professor of Microbiology at the University of California, writes that 50 percent of botulism in America is due to infant botulism. In wound botulism, the spores enter a wound, germinate and make the toxin in the wound.
Campylobacter Jejuni
C. jejuni is a gram negative rod. It is rod-shaped, but is gram negative because it does not hold onto the first stain in the gram stain process. Campylobacter is able to invade and destroy the mucosa layer of the intestines. This causes enteritis, or the inflammation of the intestines. The symptoms include abdominal pain, nausea, vomiting, fever and bloody diarrhea.
References
- "Jawetz, Melnick, and Adelberg's Medical Microbiology"; George Brooks, M.D., Karen Carroll, M.D., Janet Butel, Ph.D., Stephen Morse, Ph.D.; 2007
- "Review of Medical Microbiology and Immunology," Warren Levinson, M.D., Ph.D.; 2008
- The Merck Manual for Healthcare Professionals: Actinomycosis
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