The problem of Clostridium difficile (C.diff)

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Introduction

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Behavior

Spores

Clostridium difficile spores are extremely hardy, and can survive for long amounts of time in environments devoid of food. The spores are resistant to drying and heating, and also have resistance to many forms of antiseptic cleaners. One of the few ways to kill C. diff. spores is to use a form of bleach. C. diff can also survive in spore form for as long as five months. The ability of C. diff. to survive in this resistant form poses quite a challenge for hospitals.

Germination

C. Diff can change into its vegetative, disease causing state when it reaches the intestine of humans. As an anaerobe, it thrives without oxygen. Human intestine also contains glycine and cholate derivatives, which are the two substances that C. diff requires to germinate. In healthy intestines with a normal population of microbes, cholate derivatives are further processed by the other bacteria present, thus preventing germination of the foreign C. diff. bacteria. After broad-spectrum antibiotic treatment, much of the microflora of the intestine is disrupted or killed; this prevents the further processing of cholate, and allows C. diff. to germinate and flourish. This also gives C. diff. more space in the intestine, as much of the other microbes that would ordinarily be in the intestine have been destroyed by the antibiotic treatment.

Pathology

How you catch C. diff.

Clostridium difficile is most often acquired in hospitals or health-care settings as a result of environmental contamination. Surfaces are contaminated with fecal matter, including C. diff. which then can be spread by contact with humans. Then it can travel through the digestive system in spore form until it reaches its favored habitat, the intestine. This shows the importance of proper sanitation when dealing with patients infected with C. diff. as well as the need to completely disinfect the room with the proper cleaning protocols.

Toxicity

Upon reaching the intestine, C. diff. enters a vegetative state and begins to spread. It also begins to secrete toxin A, an enterotoxin and toxin B, a cytotoxin. Toxin A works to create holes in cells, causing their contents to leak out. This presents as diarrhea in patients, as excess cell fluid enters the intestine. Cytotoxins simply cause damage to cells; it is not as narrow a category as enterotoxins. Toxin B causes damage to the cytoskeleton of cells which can cause inflammation and present as abdominal pain or colitis.

Symptoms

C. diff infection is characterized by several symptoms. It generally presents initially as diarrhea and abdominal pain, or colitis. This is directly caused by the toxins introduced by C. diff. This can lead to fever. Pseudomembraneous colitis is most commonly caused by C. diff. infection. If left untreated it is possible for this to progress to toxic megacolon which can lead to sepsis and death.

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References

[Roger W. Harms, M.D. et al. November 3, 2010. “’’C. difficile’’”. http://www.mayoclinic.com/health/c-difficile/DS00736] [Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by Matthew Glatt, Samantha Bonnel, Husam Abdala and Thomas Henshall, students of Rachel Larsen in Bio 083 at Bowdoin College [1]