Assessing Diagnostic Methods for Multidrug-Resistant Tuberculosis: A Comprehensive Review

Papan Cihan^*
*Correspondence: Papan Cihan, Department of Infectious Diseases, University of Freiburg, Fahnenbergplatz, Germany, Email:

Keywords

Multidrug-resistant tuberculosis • Drug-susceptible testing • Polymerase chain reaction

Introduction

Multidrug-Resistant Tuberculosis (MDR-TB) poses a significant threat to global public health, challenging Tuberculosis (TB) control efforts worldwide. The primary cause of MDR-TB is inadequate or improper treatment of drugsusceptible TB. When patients do not complete their full course of treatment or are prescribed incorrect drug regimens, the TB bacteria can survive and develop resistance to the drugs used. Additionally, MDR-TB can be acquired through direct transmission from a person already infected with drug-resistant strains. MDR-TB is a transmissible disease and can be spread through the air when an infected individual coughs, sneezes, or talks. Factors contributing to the spread of MDR-TB include overcrowded living conditions, poor ventilation and inadequate infection control measures in healthcare settings. The signs and symptoms of MDR-TB are similar to those of drug-susceptible TB [1]. They include persistent cough, fever, night sweats, weight loss, fatigue and chest pain. However, MDRTB is more difficult to diagnose due to its resistance to first-line drugs, leading to delays in appropriate treatment initiation.

Literature Review

The diagnosis of MDR-TB requires specialized laboratory testing. Conventional culture and Drug Susceptibility Testing (DST) are performed to determine drug resistance patterns. However, these methods are time-consuming and may take several weeks to provide results. To overcome this challenge, rapid molecular diagnostic techniques, such as Polymerase Chain Reaction (PCR) and Line Probe Assays (LPAs), have been developed to detect drug resistanceassociated genetic mutations more quickly. Treating MDR-TB is complex and requires the use of second-line anti-TB drugs, which are less effective, more toxic, and often more expensive [2]. The treatment regimen for MDR-TB is longer, lasting up to two years, compared to the standard six-month treatment for drugsusceptible TB. Adherence to treatment is critical to prevent the development of further drug resistance.

MDR-TB management also involves infection control measures to prevent transmission in healthcare facilities and the community. This includes ensuring proper ventilation, implementing effective respiratory hygiene practices and using personal protective equipment. Preventing the emergence and spread of MDR-TB requires a comprehensive approach. It includes early diagnosis and prompt initiation of appropriate treatment for drug-susceptible TB, adherence to treatment regimens, improved infection control measures and surveillance of drug resistance patterns. Additionally, efforts to develop new and more effective anti-TB drugs and vaccines are essential in combating MDR-TB [3].

Discussion

Conventional methods, such as sputum culture and DST, have long been the gold standard for diagnosing TB. However, these techniques are time-consuming, taking several weeks to obtain results. We discuss the challenges associated with conventional DST and the need for faster and more efficient diagnostic approaches. Polymerase Chain Reaction (PCR) based assays, including line probe assays (LPAs) and GeneXpert MTB/RIF, have revolutionized TB diagnosis. These techniques detect the presence of specific genetic markers, such as mutations in the rpoB gene associated with rifampicin resistance. We examine the advantages and limitations of PCR-based methods in MDR-TB diagnosis. Next- Generation Sequencing (NGS) technologies offer unprecedented resolution in detecting drug-resistant mutations and strain characterization [4]. We explore the potential of NGS in MDR-TB diagnosis and its role in understanding transmission dynamics and drug resistance mechanisms.

Phenotypic Drug Susceptibility Testing (DST)

Liquid culture-based DST systems, such as the MGIT (Mycobacterial Growth Indicator Tube) and the Microscopic Observation Drug Susceptibility (MODS) assay, offer faster turnaround times compared to conventional solid culture methods. We discuss the benefits and challenges of liquid culture techniques [5]. Novel phenotypic assays, such as the nitrate reductase assay and colorimetric methods have emerged as potential alternatives to traditional DST. We evaluate the utility and reliability of these rapid phenotypic methods for MDR-TB diagnosis. We delve deeper into the specifics of commercially available line probe assays, such as the Genotype MTBDRplus and Genotype MTBDRsl, which enable simultaneous detection of resistance to multiple anti-TB drugs. Whole genome sequencing provides a comprehensive view of the genetic makeup of MDR-TB strains, facilitating the identification of drug resistance-associated mutations [6]. We discuss the current status and future prospects of this promising technology.

Conclusion

MDR-TB poses a significant challenge to global TB control efforts. Its diagnosis, treatment, and prevention require a multifaceted approach involving improved laboratory diagnostics, effective drug regimens, infection control measures and public health interventions. Addressing MDR-TB requires sustained commitment, resources, and collaboration between healthcare providers, policymakers, researchers and communities to reduce its impact and prevent its further spread. Accurate and timely diagnosis of MDR-TB is crucial for patient care and controlling the spread of drug-resistant strains. In this comprehensive review, we have highlighted various diagnostic techniques employed for MDRTB detection, ranging from conventional culture methods to advanced molecular and phenotypic assays. While each technique has its advantages and limitations, ongoing research and technological advancements continue to shape the landscape of MDR-TB diagnostics. A multidimensional approach, incorporating the strengths of different methods, holds the key to effective MDR-TB control and management in the future.

Acknowledgement

None.

Conflict of Interest

None.

References

1. Jenkins, Helen E., Valeriu Plesca, Anisoara Ciobanu and Valeriu Crudu, et al. "Assessing spatial heterogeneity of multidrug-resistant tuberculosis in a high-burden country." Eur Respir J 42 (2013): 1291-1301.

Google Scholar, Crossref, Indexed at

2. Seddon, James A., Sarah Johnson, Megan Palmer and Marieke M. Van Der Zalm, et al. "Multidrug-resistant tuberculosis in children and adolescents: Current strategies for prevention and treatment." Expert Rev Respir Med 15 (2021): 221-237.

Google Scholar, Crossref, Indexed at

3. Ling, Daphne I., Alice A. Zwerling and Madhukar Pai. "GenoType MTBDR assays for the diagnosis of multidrug-resistant tuberculosis: A meta-analysis." Eur Respir J 32 (2008): 1165-1174.

Google Scholar, Crossref, Indexed at

4. Villarino, Margarita E., Lawrence J. Geiter and Patricia M. Simone. "The multidrug-resistant tuberculosis challenge to public health efforts to control tuberculosis." Public Health Rep 107 (1992): 616.

Google Scholar, Indexed at

5. Pradipta, Ivan Surya, Lina Davies Forsman, Judith Bruchfeld and Eelko Hak, et al. "Risk factors of multidrug-resistant tuberculosis: A global systematic review and meta-analysis." J Infect 77 (2018): 469-478.

Google Scholar, Crossref, Indexed at

6. Gandhi, Neel R., Paul Nunn, Keertan Dheda and H. Simon Schaaf, et al. "Multidrug-resistant and extensively drug-resistant tuberculosis: A threat to global control of tuberculosis." The Lancet 375 (2010): 1830-1843.

Google Scholar, Crossref