Drug-resistant TB

Overview

Drug-resistant TB or tuberculosis is caused by TB germs that are resistant to at least one of the most effective medicines for treating the TB disease. Thus, these medicines can no longer cure the disease. Isoniazid and rifampin are the two primary medicines known to treat tuberculosis; the drug-resistant TB strain deems these drugs ineffective.

Drug-resistant TB is spread through the same transmission process as drug-sensitive TB. Note that a delay in the diagnosis of drug-resistant TB can result in the strengthening of resistance against anti-TB medicines. So, it would be prudent to go for diagnosis immediately upon noticing symptoms and following the prescribed treatment plan closely.

What is Drug-resistant TB?

Drug-resistant TB is caused by bacteria that have developed resistance against primary TB-curing medicines, including isoniazid and rifampicin. It is the type of tuberculosis bacteria that does not respond predictably to these usual drugs prescribed to the infected individual, as part of the treatment plan. Therefore, the treatment procedure becomes much more expensive and challenging. This variation of tuberculosis is associated with greater risks of transmission and sometimes, complete failure of treatment.

Types of Drug-resistant TB

The complexity level of the treatment process of drug-resistant TB differs, depending upon the type of disease an individual is diagnosed with. Here are the different types of drug-resistant diseases:

Mono-resistant TB Disease (MR-TB)

Mono-resistant TB disease is caused by TB bacteria that have developed resistance to one drug prescribed to treat the disease.

Poly-resistant TB Disease (PR-TB)

Poly-resistant TB disease is caused by TB bacteria which nullifies the effects of two or more TB drugs. However, note that these do not include both, isoniazid or rifampin.

Multidrug-resistant TB Disease (MDR-TB)

Multidrug-resistant TB disease is caused by bacteria which at least resists the effects of isoniazid and rifampin.

Pre-extensively Drug-resistant Disease (Pre-XDR TB)

Pre-XDR TB may be resistant to first-line TB treatment medicines including isoniazid, rifampin and fluoroquinolone. This disease may also resist the combative effects of isoniazid, rifampin and an injectable (capreomycin, kanamycin and amikacin).

Extensively Drug-resistant TB (XDR-TB)

This is a rare type of TB caused by bacteria resistant to isoniazid, rifampin, fluoroquinolone and an injectable. It may also resist isoniazid, rifampin, fluoroquinolone and linezolid/bedaquiline.

Rifampin-resistant (RR-TB)

As the name suggests, RR-TB is caused by bacteria resistant to rifampin.

Symptoms of Drug-resistant TB

Symptoms of drug-resistant TB are not starkly different from tuberculosis itself. However, they last longer and cannot be eliminated with the usual TB drugs. Symptoms include a persistent cough for 3 weeks or more; the infected individual coughs up mucus and sometimes, blood.

Other signs are weakness, fatigue upon engaging in minimal physical activity, noticeable weight loss, loss of appetite, etc. People with tuberculosis may also develop high fever and experience chills now and then. Night sweats and unsound sleeping patterns are also commonly recorded symptoms.

Causes of Drug-resistant TB

Drug-resistant TB may be caused by primary or secondary degrees of resistance to drugs. Primary drug resistance is triggered by the transmission of drug-resistant TB bacteria from one person to another. Secondary drug resistance may develop during the TB treatment process.

For example, if the treatment regimen is not appropriately prescribed or followed by the patient; or if the body does not absorb the medication - resistance may be developed. Low serum levels may also contribute to this resistance build-up. This leads to the racking up of bills and expensive consultations, with rising requirements for newer approaches towards treating the infected person. People with COPD, obstructive pulmonary disease or bronchiectasis are at risk of developing the condition.

Drug-Resistant TB Diagnosis and Tests

Drug sensitivity tests are conducted to determine whether or not one has drug-resistant TB. According to the test results, healthcare professionals shall chalk out the plan of action and prescribe treatment accordingly. The treatment regimen may be much more complex, but it is what is most likely to fetch results.

If the infected individual does not seem to get better or has a positive culture for M. tuberculosis, the drug sensitivity tests should be re-done later. Molecular detection of drug resistance, a drug sensitivity testing method, includes lab tests, and examining respiratory samples. Other testing procedures include growth-based drug sensitivity tests and second-line drug sensitivity tests.

Treatment of Drug-resistant TB

People with drug-resistant TB need to be cured with anti-TB medicines which are especially strong enough to kill the bacteria. According to the type of drug-resistant TB one is diagnosed with, the healthcare professionals will prescribe a treatment plan. The getting better process shall take months or years to fully set in, with healthcare professionals constantly required to keep updated on the patient's health status.

Directly Observed Therapy (DOT) is a way to get treated for drug-resistant TB, where the patient will meet with a healthcare professional every day or multiple times per week. The meeting may be conducted in person or over call. This professional will make sure that the patient is taking the medication as and when they must, and that they are working.

Preventive Measures for Drug-resistant TB

To avoid developing drug-resistant TB, the infected person must get checked out by a TB expert. They will be better equipped with the knowledge of how to go through with an appropriate treatment plan. It is also the responsibility of the diagnosed individual to follow the treatment regimen closely, as a precaution against drug-resistant TB.

Myths and Facts Related to Drug-resistant TB

Here are some misconceptions related to drug-resistant TB and the facts to clear them up:

Myth 1: MDR-TB is Non Curable

Fact: MDR-TB is curable. Drug sensitivity tests must be conducted to detect drug resistance. Based on these test results, an appropriate treatment plan shall be prescribed by the respective healthcare professionals. If the treatment regimen is followed thoroughly, the condition is curable.

Myth 2: People Probably Won’t Get Drug-resistant TB Easily

Fact: While TB is often mistaken as a disease of the past, it is not the case. Even with treatment options and care facilities being available, the illness kills a lot of patients. It is important that the suffering person strictly follows the treatment plan, or they shall be susceptible to the development of drug-resistant TB.

Myth 3: Drug-resistant TB Can Be Spread through Sharing Cutlery

Fact: Drug-resistant TB cannot be spread merely through sharing cutlery with someone. One has to be exposed to TB droplets in the air for extensive hours, typically over eight hours, to contract the disease.