Advertisement
 

doctorslounge.com

 
Powered by
Careerbuilder

 

                    Home  |  Forums  |  Humor  |  Advertising  |  Contact
   Ask a Doctor

   News via RSS

   Newsletter

   Infections

   News

 

 Conferences


   CME

   Forum Archives

   Diseases

   Symptoms

   Labs

   Procedures

   Drugs

   Links
   Specialties

   Cardiology

   Dermatology

   Endocrinology

   Fertility

   Gastroenterology

   Gynecology

   Hematology

   Infections

   Nephrology

   Neurology

   Oncology

   Orthopedics

   Pediatrics

   Pharmacy

   Primary Care

   Psychiatry

   Pulmonology

   Rheumatology

   Surgery

   Urology

   Other Sections

   Membership

   Research Tools

   Medical Tutorials

   Medical Software

 

 Headlines:

 
 

Back to Bacteria Index

Clostridium tetani

Member of genus Clostridium

Epidemiology

There are about one million cases of tetanus reported worldwide and about 70 in the United States annually. Most cases in the US are in the elderly who have allowed their innoculations to lapse, whereas most cases in developing countries are in newborns.

History

Tetanus, the disease, was known to the ancients, who recognized the relationship between wounds and fatal muscle spasms. In 1884, the strychnine-like toxin of tetanus was isolated from free-living, anaerobic soil bacteria. In 1890, tetanus toxoid was developed, providing active immunization against the illness. This is our modern tetanus vaccine.

Morphology

Clostridium tetani is a gram positive, spore-forming, obligate anaerobic, rod-shaped bacterium of the phylum firmicutes. C. tetani's appearance on gram stain is said to resemble tennis rackets or drumsticks. Found in nature as spores in soil or parasitising the gastrointestinal tracts of animals, these bacteria cause serious toxicity in humans. See excellent article on tetanus.

Cultural characteristics

C. tetani is an obligately anaerobic bacillus that stains gram positive in fresh cultures, but may stain gram negative in older cultures.

Pathogenesis

During growth, the germ possesses many flagellae and have limited mobility. Two toxins are elaborated, tetanospasmin and tetanolysin, the latter of which is of uncertain toxicity and significance. As the organism matures, it develops a terminal spore, giving it the characteristic tennis racket appearance. Spores are exteremely hardy but can be rendered harmless by iodine, hydrogen peroxide or heat and pressure treatment (autoclaving). From a clinical viewpoint, growing the organism from a wound is of no significance.

Toxicity

Tetanospasmin is similar in structure to botulinum toxin, but very different in effect. It is a zinc-dependent metalloproteinase. There is a heavy protein chain and a light chain connected by a disulfide bridge. The heavy chain attaches to the cellular receptor, and the light chain produces the toxic effects. It enters the central nervous system by binding to the ends of axons and traveling up the axon to the cell bodies. There, it blocks the release of neurotransmitter from inhibitory neurons to motor cells. The motor neurons then fire because of unopposed action of excitatory neurons, leading to diffuse muscle spasm.

Diseases caused by clostridium tetani

advertisement.gif (61x7 -- 0 bytes)
 

Are you a doctor or a nurse?

Do you want to join the Doctors Lounge online medical community?

Participate in editorial activities (publish, peer review, edit) and give a helping hand to the largest online community of patients.

Click on the link below to see the requirements:

Doctors Lounge Membership Application



previous.gif (72x17 -- 347 bytes) next.gif (72x17 -- 277 bytes)
 

 advertisement.gif (61x7 -- 0 bytes)

 

 



We subscribe to the HONcode principles of the HON Foundation. Click to verify.
We subscribe to the HONcode principles. Verify here

Privacy Statement | Terms & Conditions | Editorial Board | About us
Copyright 2001-2012 DoctorsLounge. All rights reserved.