Multi-drug Resistant Tuberculosis — MCQs
Multi drug resistant tuberculosis is defined as resistance to?
Which of the following is not included in the Revised National Tuberculosis Control Programme (RNTCP)?
Which of the following is an inclusion criterion for the shorter bedaquiline regimen in the treatment of tuberculosis?
Which of the following is the true statement regarding measures to prevent typhoid transmission in the community?
Not True about Bedaquiline
A 50-year-old farmer presents with cough, fever, and weight loss. CXR shows upper lobe cavitary lesions. Sputum culture reveals acid-fast bacilli resistant to isoniazid and rifampin. What is the next best drug?
Multidrug-resistant (MDR) tuberculosis shows resistance to which of the following drugs?
Which of the following methods is not suitable for testing anti-tubercular drug susceptibility?
Anti-tubercular drug susceptibility can be done by all of the following methods, except?
Multiple drug resistance is transferred through -
Multi-drug Resistant Tuberculosis Indian Medical PG Practice Questions and MCQs
Question 1: Multi drug resistant tuberculosis is defined as resistance to?
- A. Rifampicin and Pyrazinamide
- B. INH and Rifampicin (Correct Answer)
- C. Resistance to all first line drugs
- D. INH and Pyrazinamide
Explanation: ***INH and Rifampicin*** - **Multidrug-resistant tuberculosis (MDR-TB)** is specifically defined by resistance to at least **isoniazid (INH)** and **rifampicin** [1], which are the two most potent first-line anti-TB drugs. - This dual resistance makes treatment significantly more challenging and prolonged compared to drug-susceptible TB. *Rifampicin and Pyrazinamide* - While resistance to these drugs is serious, it does not specifically define MDR-TB unless resistance to **isoniazid** is also present. - **Pyrazinamide** is another first-line drug, but its resistance pattern alone with rifampicin does not meet the MDR-TB criteria. *Resistance to all first-line drugs* - Resistance to all four first-line drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol) [1] is classified as **Extensively Drug-Resistant TB (XDR-TB)**, a more severe form of resistance than MDR-TB. - MDR-TB specifically refers to resistance to **INH and rifampicin**, not necessarily all first-line drugs. *INH and Pyrazinamide* - While resistance to both **isoniazid** and **pyrazinamide** is a concern, it does not meet the definition of MDR-TB. - The definition requires resistance to **rifampicin** in addition to isoniazid.
Question 2: Which of the following is not included in the Revised National Tuberculosis Control Programme (RNTCP)?
- A. Chest X-rays are used as a diagnostic tool for tuberculosis.
- B. Directly observed therapy (DOT) is a key strategy in tuberculosis control.
- C. Active case finding is a strategy used in tuberculosis control. (Correct Answer)
- D. Daily drug administration is part of the tuberculosis treatment regimen.
Explanation: ***Active case finding is a strategy used in tuberculosis control*** - **This is the correct answer** - Traditional RNTCP primarily relied on **passive case finding**, where symptomatic patients self-report to health facilities - While active case finding (systematic screening of high-risk groups) is now emphasized in NTEP (National TB Elimination Programme), it was **not a major strategy in the original RNTCP framework** - The classic RNTCP approach focused on identifying patients who presented with symptoms rather than actively seeking cases in the community *Directly observed therapy (DOT) is a key strategy in tuberculosis control* - **DOT is a cornerstone** of RNTCP/NTEP to ensure treatment adherence - A trained provider directly observes the patient taking anti-TB medications - This prevents treatment default and reduces drug resistance *Chest X-rays are used as a diagnostic tool for tuberculosis* - **Chest X-rays are integral** to RNTCP for screening and diagnosis of pulmonary TB - Used in conjunction with sputum microscopy/molecular tests like CBNAAT - Helps identify lung involvement and assess disease severity *Daily drug administration is part of the tuberculosis treatment regimen* - **RNTCP/NTEP uses daily drug regimens** for most TB categories (replaced older intermittent regimens) - Daily dosing improves treatment efficacy and patient adherence - Part of the standardized treatment protocols under the programme
Question 3: Which of the following is an inclusion criterion for the shorter bedaquiline regimen in the treatment of tuberculosis?
- A. Extrapulmonary TB like Tubercular meningitis
- B. Rifampicin resistance with both KatG and inhA mutation
- C. Rifampicin-sensitive TB
- D. Rifampicin-resistant but fluoroquinolone-sensitive TB (Correct Answer)
- E. Extensively drug-resistant TB (XDR-TB)
Explanation: ***Rifampicin-resistant but fluoroquinolone-sensitive TB*** - The **shorter bedaquiline regimen** is specifically recommended for patients with **rifampicin-resistant tuberculosis** who are also sensitive to fluoroquinolones. - This regimen optimizes treatment outcomes by leveraging the effectiveness of both bedaquiline and a potent fluoroquinolone against sensitive strains. *Extrapulmonary TB like Tubercular meningitis* - The shorter bedaquiline regimen is generally not recommended for severe forms of **extrapulmonary TB**, especially those involving the **central nervous system**, due to concerns about drug penetration and efficacy. - These cases often require longer, individualized regimens with stronger central nervous system penetration. *Rifampicin resistance with both KatG and inhA mutation* - The presence of both **KatG** and **inhA mutations** indicates high-level **isoniazid resistance**, which is not the primary criterion for selecting the shorter bedaquiline regimen. - While these mutations are important for guiding isoniazid use, the core inclusion for this regimen is **rifampicin resistance** and **fluoroquinolone sensitivity**. *Rifampicin-sensitive TB* - Patients with **rifampicin-sensitive TB** are usually treated with standard first-line regimens that do not include bedaquiline, as their disease is susceptible to more conventional therapies. - The shorter bedaquiline regimen is reserved for drug-resistant cases, particularly those with rifampicin resistance. *Extensively drug-resistant TB (XDR-TB)* - While **XDR-TB** patients may receive bedaquiline, they typically require **longer, individualized regimens** rather than the shorter standardized regimen. - The shorter bedaquiline regimen is primarily indicated for **rifampicin-resistant TB** that is **fluoroquinolone-sensitive**, whereas XDR-TB involves resistance to both fluoroquinolones and injectable agents, requiring more complex treatment approaches.
Question 4: Which of the following is the true statement regarding measures to prevent typhoid transmission in the community?
- A. Typhoid vaccine administration is the best method of preventing transmission.
- B. Person-to-person transmission is the primary mode of spread.
- C. Drug resistance in typhoid is not as big a problem as in TB.
- D. Hygiene practice and clean sanitation control are more important than the typhoid vaccine. (Correct Answer)
Explanation: ***Hygiene practice and clean sanitation control is more important than the typhoid vaccine.*** - **Improved sanitation**, safe water supplies, and adequate hygiene practices are fundamental in controlling the spread of **typhoid fever**, as the disease is primarily transmitted through the **oral-fecal route**. - While vaccines are an important tool, they offer only partial protection and must be combined with **robust public health infrastructure** and **sanitation measures** for effective prevention. *Typhoid vaccine administration is the best method of preventing transmission.* - Typhoid vaccines offer protection, but their effectiveness is not 100%, and they typically require **booster doses** - **Vaccination campaigns** are most effective when implemented alongside improvements in **water and sanitation infrastructure**, as vaccines alone cannot fully prevent transmission in areas with poor hygiene. *Person-to-person transmission is the primary mode of spread.* - While person-to-person transmission can occur, especially in settings with poor hygiene, the primary mode of spread for typhoid is through the **ingestion of food or water contaminated** with the feces of an infected person or carrier. - This emphasizes the crucial role of **water and food safety** rather than just focusing on direct person-to-person contact. *Drug resistance in typhoid is not as big a problem as in TB.* - **Antimicrobial resistance (AMR)** in typhoid fever, particularly to fluoroquinolones and extended-spectrum beta-lactamase (ESBL) producing strains, is a **significant and growing global health concern**, complicating treatment. - While TB also faces serious drug resistance issues, the escalating problem of **extensively drug-resistant (XDR)** and **multi-drug resistant (MDR)** typhoid strains makes it a substantial threat, impacting treatment options and increasing morbidity and mortality.
Question 5: Not True about Bedaquiline
- A. Inhibits mycobacterial ATP synthase
- B. Contraindicated in pregnancy (Correct Answer)
- C. Given in > 10 years aged patients
- D. Given for MDR-TB patients
Explanation: ***Contraindicated in pregnancy*** - While bedaquiline's safety in pregnancy is not fully established, it is generally **not absolutely contraindicated** if the potential benefits outweigh the risks, especially in cases of MDR-TB. - Current guidelines suggest that it can be used with caution, and a woman taking bedaquiline should use **effective contraception** throughout treatment. *Inhibits mycobacterial ATP synthase* - This statement is **true**. Bedaquiline specifically targets the **F0F1-ATP synthase enzyme** in *Mycobacterium tuberculosis*. - By inhibiting this enzyme, bedaquiline disrupts the **energy production** pathway of the bacteria, leading to bacterial death. *Given in > 10 years aged patients* - This statement is **true**. Bedaquiline is approved for use in patients with **multidrug-resistant tuberculosis (MDR-TB)** who are **12 years of age and older**. - Its use in younger children is still under investigation, though some compassionate use cases exist. *Given for MDR-TB patients* - This statement is **true**. Bedaquiline is a key drug in the treatment of **multidrug-resistant tuberculosis (MDR-TB)** and **extensively drug-resistant tuberculosis (XDR-TB)**. - It is often used as part of a **combination regimen** to overcome drug resistance to first-line agents.
Question 6: A 50-year-old farmer presents with cough, fever, and weight loss. CXR shows upper lobe cavitary lesions. Sputum culture reveals acid-fast bacilli resistant to isoniazid and rifampin. What is the next best drug?
- A. Linezolid
- B. Fluoroquinolone (Correct Answer)
- C. Ethambutol
- D. Pyrazinamide
Explanation: **Fluoroquinolone** - In cases of **multidrug-resistant tuberculosis (MDR-TB)**, which is defined by specific resistance to both **isoniazid** and **rifampin**, fluoroquinolones are a crucial second-line agent [1]. - They demonstrate excellent **mycobactericidal activity** and are a cornerstone of MDR-TB treatment regimens [1]. *Linezolid* - While **Linezolid** is used in highly resistant TB cases (XDR-TB), it is generally reserved for situations where other core second-line drugs (like fluoroquinolones) cannot be used or are resistant. - Its use often carries a higher risk of **myelosuppression** and **neuropathy**, making it less preferred as an initial choice for MDR-TB. *Ethambutol* - **Ethambutol** is a first-line antitubercular drug, but it is typically used in conjunction with isoniazid and rifampin to prevent resistance development [1]. - It would not be the "next best" drug when **TB is already resistant to isoniazid and rifampin**, as single-drug therapy is ineffective for MDR-TB and could lead to further resistance. *Pyrazinamide* - **Pyrazinamide** is another first-line drug primarily effective against semi-dormant bacilli in acidic environments [1]. - Similar to ethambutol, it is not appropriate as the "next best" drug to manage **MDR-TB** when resistance to standard first-line agents has already been identified.
Question 7: Multidrug-resistant (MDR) tuberculosis shows resistance to which of the following drugs?
- A. Isoniazid, rifampicin, and fluoroquinolone
- B. Fluoroquinolone
- C. Isoniazid, rifampicin, and kanamycin
- D. Isoniazid and rifampicin only (Correct Answer)
Explanation: ***Isoniazid and rifampicin only*** - **Multidrug-resistant (MDR) tuberculosis** is specifically defined by resistance to both **isoniazid** and **rifampicin**. - These two drugs are considered the most effective first-line anti-TB medications, making resistance to both a significant treatment challenge. *Isoniazid, rifampicin, and fluoroquinolone* - Resistance to **isoniazid**, **rifampicin**, and *any* fluoroquinolone defines **pre-extensively drug-resistant (pre-XDR) TB**, not MDR-TB. - Adding resistance to a fluoroquinolone indicates a more severe and harder-to-treat form of tuberculosis. *Fluoroquinolone* - Resistance to **fluoroquinolone** alone does not define MDR-TB; it is only one component of resistance that, when combined with resistance to isoniazid and rifampicin, signifies pre-XDR or XDR-TB. - While fluoroquinolones are important second-line drugs, their resistance in isolation does not meet the criteria for MDR-TB. *Isoniazid, rifampicin, and kanamycin* - Resistance to **isoniazid**, **rifampicin**, and *any* second-line injectable agent (like **kanamycin**, capreomycin, or amikacin) defines **extensively drug-resistant (XDR) TB**, not MDR-TB. - XDR-TB represents an even more complex and difficult form of the disease to treat, requiring highly specialized regimens.
Question 8: Which of the following methods is not suitable for testing anti-tubercular drug susceptibility?
- A. Resistance ratio method
- B. Disc diffusion method (Correct Answer)
- C. Radiometric broth method
- D. Molecular method
Explanation: ***Disc diffusion method*** - The **disc diffusion method** is generally **not suitable** for *Mycobacterium tuberculosis* due to its **slow growth rate** and the **hydrophobic cell wall** that hinders drug diffusion. - This method requires a relatively fast-growing organism to produce a measurable zone of inhibition within a standard incubation period, which *M. tuberculosis* does not. *Resistance ratio method* - The **resistance ratio method** is a conventional susceptibility testing method for *Mycobacterium tuberculosis* that compares the **minimum inhibitory concentration (MIC)** of a drug against the test strain to a susceptible reference strain. - This method is considered reliable for assessing drug resistance in *M. tuberculosis* but can be time-consuming. *Molecular method* - **Molecular methods** (e.g., **PCR-based assays**, **GeneXpert**, **gene sequencing**) are highly suitable for detecting **anti-tubercular drug resistance** by identifying specific mutations in genes associated with resistance (e.g., *rpoB* for rifampicin, *katG* for isoniazid). - These methods offer **rapid results** and can detect resistance even in paucibacillary samples. *Radiometric broth method* - **Liquid culture systems** such as **BACTEC MGIT 960** are rapid and automated methods commonly used for *M. tuberculosis* susceptibility testing. - **MGIT 960** uses a **fluorescence-based** detection system that measures **oxygen consumption** by metabolizing mycobacteria (fluorescence quenching), providing faster results than traditional solid media methods. - The older **BACTEC 460** used a true radiometric method (detecting **¹⁴CO₂** from radiolabeled substrates) but has been largely replaced by non-radiometric systems.
Question 9: Anti-tubercular drug susceptibility can be done by all of the following methods, except?
- A. Molecular method
- B. Resistance ratio method
- C. Disc diffusion method (Correct Answer)
- D. Radiometric broth method
Explanation: ***Disc diffusion method*** - The **disc diffusion method** is generally not reliable for *Mycobacterium tuberculosis* due to its slow growth rate, unique cell wall, and lipophilic nature, which hinder effective diffusion of antimicrobial agents. - This method is primarily used for rapidly growing bacteria, unlike the **slow-growing** *M. tuberculosis*. *Molecular method* - **Molecular methods**, such as PCR-based assays, rapidly detect resistance-associated mutations in genes (e.g., *rpoB* for rifampicin, *katG* for isoniazid). - They provide quick and accurate results for drug susceptibility testing, which is crucial for timely treatment initiation. *Resistance ratio method* - The **resistance ratio method** quantifies drug resistance by comparing the minimum inhibitory concentration (MIC) of a test strain to that of a susceptible reference strain. - A resistance ratio greater than 1 indicates resistance, offering a precise measure of drug efficacy. *Radiometric broth method* - The **radiometric broth method**, like BACTEC MGIT 960, detects growth of *M. tuberculosis* by measuring CO2 production from radiolabeled palmitic acid, providing rapid susceptibility results. - This method significantly reduces the time for susceptibility testing compared to conventional solid media methods.
Question 10: Multiple drug resistance is transferred through -
- A. Transduction
- B. Transformation
- C. Conjugation (Correct Answer)
- D. Mutation
Explanation: ***Conjugation*** - Conjugation is a primary mechanism for the spread of **antibiotic resistance genes** among bacteria, including those responsible for multiple drug resistance. - It involves the direct transfer of **plasmids** (which often carry resistance genes) from one bacterial cell to another through a pilus. *Transduction* - Transduction is the process where bacteria acquire foreign DNA, including resistance genes, via a **bacteriophage (virus)**. - While it can transfer resistance, conjugation is a more common and clinically significant route for **multidrug resistance** spread. *Transformation* - Transformation involves the uptake of **naked DNA** from the environment by a bacterial cell. - While bacteria can acquire resistance genes this way, it is less efficient for widespread, rapid transfer of **multiple resistance traits** compared to conjugation. *Mutation* - Mutation refers to a change in the bacterial organism's own DNA, which can lead to the development of **drug resistance**. - However, mutation explains the *origin* of resistance in a single bacterium, not the *transfer* of resistance genes (especially multiple resistance) between different bacteria.
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