Tuberculosis (cont.)
What is drug-resistant TB?
Drug-resistant TB (TB that does not respond to drug treatment) has become a very serious problem in recent years in certain populations. For example, INH-resistant TB is seen among patients from Southeast Asia. The presence of INH-like substances in the cough syrups in that part of the world may play a role in causing the INH resistance. Drug-resistant cases are also often seen in prison populations. However, the major reason for the development of resistance is poorly managed TB care. This can result from poor patient compliance, inappropriate dosing or prescribing of medication, poorly formulated medications, and/or an inadequate supply of medication. Multidrug-resistant tuberculosis (MDR-TB) refers to organisms that are resistant to at least two of the first-line drugs, INH and Rifampin. More recently, extensively (extremely) drug resistant tuberculosis (XDR-TB) has emerged. These bacteria are also resistant to three or more of the second-line treatment drugs.
XDR-TB is seen throughout the world but is most frequently seen in the countries of the former Soviet Union and Asia.
Preventing XDR-TB from spreading is essential. The World Health Organization (WHO) recommends improving basic TB care to prevent emergence of resistance and the development of proper laboratories for detection of resistant cases. When drug-resistant cases are found, prompt, appropriate treatment is required. This will prevent further transmission. Collaboration of HIV and TB care will also help limit the spread of tuberculosis, both sensitive and resistant strains.
What's in the future for TB?
Conceivably, TB could have been eliminated by effective treatment,
vaccinations, and public-health measures by the year 2000. However, the
emergence of HIV changed the whole picture. Because of HIV, a tremendous
increase in the frequency (incidence) of TB occurred in the '80s and throughout
the '90s. This increase in TB happened because suppression of the body's immune
(defense) system by HIV allowed TB to occur as a so-called opportunistic
infection. With the increasing HIV epidemic in Africa, serious concerns are being raised about the development of MDR-TB and XDR-TB in this population. Hopefully, control of HIV in the future will check this resurgence of
tuberculosis.
- Tuberculosis (TB) is an infection, primarily in the lungs (a pneumonia),
caused by bacteria called Mycobacterium tuberculosis. It is spread usually from
person to person by breathing infected air during close contact.
- TB can remain in an inactive (dormant) state for years without causing
symptoms or spreading to other people.
- When the immune system of a patient with dormant TB is weakened, the TB can
become active (reactivate) and cause infection in the lungs or other parts of
the body.
- The risk factors for acquiring TB include close-contact situations, alcohol
and IV drug abuse, and certain diseases (for
example, diabetes, cancer, and HIV) and
occupations (for example, health-care workers).
- The most common symptoms of TB are fatigue, fever, weight loss, coughing,
and night sweats.
- The diagnosis of TB involves skin tests, chest x-rays, sputum analysis
(smear and culture), and PCR tests to detect the genetic material of the
causative bacteria.
- Inactive tuberculosis may be treated with an antibiotic, isoniazid (INH),
to prevent the TB infection from becoming active.
- Active TB is treated, usually successfully, with INH in combination with
one or more of several drugs, including rifampin, ethambutol, pyrazinamide, and
streptomycin.
- Drug-resistant TB is a serious, as yet unsolved, public-health problem, especially in Southeast Asia, the countries of the former Soviet Union, Africa, and in prison populations. Poor patient compliance, lack of detection of resistant strains, and unavailable therapy are key reasons for the
development of drug-resistant TB.
- The occurrence of HIV has been responsible for an increased frequency of
tuberculosis. Control of HIV in the future, however, should substantially
decrease the frequency of TB.
Previous contributing author and editor:
Medical Author: Zab Mohsenifar, MD
Medical Editor: Leslie J.
Schoenfield, MD, PhD Last Editorial Review: 1/17/2008
- isoniazid-oral, Niazid - Consumer information about the medication ISONIAZID - ORAL (Niazid), includes side effects, drug interactions, recommended dosages, and storage information. Read more about the prescription drug ISONIAZID - ORAL.
- Tuberculosis Skin Test (PPD Skin Test) - The tuberculosis skin test (also known as the tuberculin or PPD test) determines whether a person has developed an immune response to the bacterium that causes tuberculosis (TB). Learn how the test is administered, how a reading is obtained, and how the results are interpreted.
- Pneumonia - Learn pneumonia symptoms, causes, treatment, signs, diagnosis and types: viral and bacterial (Pneumocystis carinii, Klebsiella, Mycoplasma, Chlamydia pneumoniae).
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