Ch. 22 - Microbial Diseases of the Nervous System

Tortora - Microbiology: An Introduction 14th Edition

Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398Not the one you use?Change textbook

Tortora 14th Edition

Ch. 22 - Microbial Diseases of the Nervous System

Problem 1

Chapter 22, Problem 1

If C. tetani is relatively sensitive to penicillin, why doesn’t penicillin cure tetanus?

Verified step by step guidance

Understand the nature of Clostridium tetani: it is an anaerobic, spore-forming bacterium that produces a potent neurotoxin called tetanospasmin, which causes the symptoms of tetanus.

Recognize that penicillin is effective at killing the vegetative (actively growing) form of C. tetani but does not affect the spores, which are resistant to antibiotics.

Consider that the symptoms of tetanus are primarily caused by the toxin already released by the bacteria, not by the bacteria themselves directly.

Realize that even if penicillin kills the bacteria, it does not neutralize the tetanospasmin toxin that has already bound to nerve endings and caused neurological damage.

Therefore, treatment of tetanus requires not only antibiotics like penicillin to stop bacterial growth but also administration of tetanus antitoxin (immunoglobulin) to neutralize the circulating toxin and supportive care to manage symptoms.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Mechanism of Tetanus Pathogenesis

Clostridium tetani causes tetanus by producing a potent neurotoxin called tetanospasmin, which blocks inhibitory neurotransmitters in the nervous system, leading to muscle spasms. The disease symptoms result from the toxin's effect, not directly from bacterial growth.

Role of Antibiotics in Tetanus Treatment

Penicillin can kill C. tetani bacteria, but it does not neutralize the tetanus toxin already released in the body. Therefore, while antibiotics stop bacterial proliferation, they cannot reverse the neurological damage caused by the toxin.

Importance of Antitoxin Therapy and Supportive Care

Effective tetanus treatment requires administration of tetanus immune globulin to neutralize circulating toxin, along with wound care and supportive measures. Antibiotics alone are insufficient because they do not address the toxin responsible for symptoms.

Recommended video:

Guided course

04:27

Environmental Benefits of Microorganisms

Related Practice

Textbook Question

What treatment is used against tetanus under the following conditions?

a. Before a person suffers a deep puncture wound

b. After a person suffers a deep puncture wound

views

Textbook Question

Which of the following does not have an animal reservoir or vector?

a. Listeriosis

b. Cryptococcosis

c. Amebic meningoencephalitis

d. Rabies

e. African trypanosomiasis

views

Textbook Question

Which of the following is false?

a. Only puncture wounds by rusty nails result in tetanus.

b. Rabies is seldom found in rodents (e.g., rats, mice).

c. Polio is transmitted by the fecal-oral route.

d. Arboviral encephalitis is rather common in the United States.

e. All of the above are true.

views

Textbook Question

A 12-year-old child hospitalized for Guillain-Barré syndrome had a 4-day history of headache, dizziness, fever, sore throat, and weakness of legs. Seizures began 2 weeks later. Bacterial cultures were negative. The child died 3 weeks after hospitalization. An autopsy revealed inclusions in brain cells that tested positive in an immunofluorescence test. This patient probably had

a. Rabies.

b. Creutzfeldt-Jakob disease.

c. Botulism.

d. Tetanus.

e. Leprosy.