How does TB drug resistance develop?
Drug resistance in TB remains a man-made phenomenon. It emerges as a result of spontaneous gene mutations in M. tuberculosis that render the bacteria resistant to the most commonly used anti-TB drugs. Among the reasons for this, the non-compliance with the treatment regimens is signaled as the first cause.
What factors contribute to the spread of drug-resistant TB?
The spread of drug resistance stems from many factors: poor public health infrastructure (e.g., delays in the diagnosis of drug resistance, inconsistencies in TB medication supply), inadequate treatment (e.g., unmonitored therapy, nonadherence, incorrect use of anti-TB agents), inefficient infection control, and the ...
Is antibiotic resistance an issue in treatment of tuberculosis?
Drug-resistant tuberculosis (DR-TB) is a form of antimicrobial resistance that is difficult and costly to treat. It is caused by TB bacteria that are resistant to at least one of the first-line existing TB medications, resulting in fewer treatment options and increasing mortality rates.
What causes drug resistance?
Microbes also may get genes from each other, including genes that make the microbe drug resistant. Bacteria multiply by the billions. Bacteria that have drug-resistant DNA may transfer a copy of these genes to other bacteria. Non-resistant bacteria receive the new DNA and become resistant to drugs.
How do you know if TB is drug resistant?
Drug resistance can be detected using special laboratory tests which test the bacteria for sensitivity to the drugs or detect resistance patterns. These tests can be molecular in type (such as Xpert MTB/RIF) or else culture-based.
Why has it become more difficult to treat TB over time?
Scientists have assumed that mycobacteria are so hard to kill because dormant cells exist even in patients with active disease and these cells are far less susceptible to antibiotics than metabolically active bacteria.
What is the mechanism responsible for antibiotic resistance in M tuberculosis?
β-lactam antibiotics bind and inhibit the activities of penicillin-binding proteins involved in cell wall biosynthesis, but mycobacteria possess β-lactamase enzymes that degrade these drugs. This is the main mechanism conferring resistance to β-lactam antibiotics.
Why is XDR TB so resistant to TB drugs?
Because XDR TB is resistant to the most potent TB drugs, patients are left with treatment options that are much less effective. XDR TB is of special concern for persons with HIV infection or other conditions that can weaken the immune system.
How to prevent MDR TB?
Another way to prevent getting MDR TB is to avoid exposure to known MDR TB patients in closed or crowded places such as hospitals, prisons, or homeless shelters. If you work in hospitals or health-care settings where TB patients are likely to be seen, you should consult infection control or occupational health experts.
What is MDR TB?
What is multidrug-resistant tuberculosis (MDR TB)? Multidrug-resistant TB (MDR TB) is caused by an organism that is resistant to at least isoniazid and rifampin, the two most potent TB drugs. These drugs are used to treat all persons with TB disease.
What are the symptoms of TB in the lungs?
The symptoms of TB disease of the lungs may also include coughing, chest pain, and coughing up blood. Symptoms of TB disease in other parts of the body depend on the area affected. If you have these symptoms, you should contact your doctor or local health department.
What to do if you think you have been exposed to someone with TB?
If you think you have been exposed to someone with TB disease, you should contact your doctor or local health department about getting a TB skin test or TB blood test. And tell the doctor or nurse when you spent time with this person.
How long does TB float in the air?
These bacteria can float in the air for several hours, depending on the environment. Persons who breathe in the air containing these TB bacteria can become infected. TB is not spread by. Shaking someone’s hand. Sharing food or drink. Touching bed linens or toilet seats. Sharing toothbrushes.
Can TB be curable?
TB usually affects the lungs, but it can also affect other parts of the body, such as the brain, the kidneys, or the spine. In most cases, TB is treatable and curable; however, persons with TB can die if they do not get proper treatment.
What is the global burden of MDR-TB?
The global burden of multidrug-resistant tuberculosis (MDR-TB) has recently increased by an annual rate of more than 20%.
Can phenotypic drug resistance be predicted?
Phenotypic drug resistance can now often, but with variable sensitivity, be predicted by molecular drug susceptibility testing based on whole genome sequencing, which in the future could become an affordable method for the guidance of treatment decisions, especially in high-burden/resource-limited settings.
Does bedaquiline help with MDR?
More recently, MDR-TB treatment outcomes have dramatically improved with the use of bedaquiline-based regimens. Ongoing clinical trials with novel and repurposed drugs will potentially further improve cure-rates, and may substantially decrease the duration of MDR-TB treatment necessary to achieve relapse-free cure.
Is MDR TB a successful disease?
According to the World Health Organization approximately only half of all patients treated for MDR-TB achieved a successful outcome. For many years, patients with drug-resistant tuberculosis (TB) have received standardized treatment regimens, thereby accelerating the development of MDR-TB through drug-specific resistance amplification.
Further reading
WHO consolidated guideline on drug-resistant tuberculosis treatment. (WHO/CDS/TB/2019.4). Geneva, World Health Organization, 2019
Acknowledgement
We would like to thank the colleagues from the Global Fund to Fight AIDS, Tuberculosis and Malaria, United States Agency for International Development and the Global Drug Facility of the Stop TB Partnership for their comments and contribution to the FAQs.