Original article / research
Year : 2026 Month : January Volume : 15 Issue : 1 Page : MO08 - MO11 Full Version

A Comparative Study of Smear Microscopy with GeneXpert MTB/RIF Assay for Rapid Detection of Mycobacterium tuberculosis and Rifampicin Resistance in a Tertiary Care Hospital: A Cross-sectional Study
Anamika Vyas, Shefali Malavav, Megha Gupta
1. Professor and Head, Department of Microbiology, Geetanjali Medical College and Hospital, Udaipur, Rajasthan, India. 2. Postgraduate Student, Department of Microbiology, Geetanjali Medical College and Hospital, Udaipur, Rajasthan, India. 3. Assistant Professor, Department of Microbiology, Geetanjali Medical College and Hospital, Udaipur, Rajasthan, India.
 
Correspondence Address :
Dr. Megha Gupta,
Department of Microbiology, Geetanjali Medical College and Hospital, Udaipur-313003, Rajasthan, India.
E-mail: megsgrt@gmail.com
 
ABSTRACT
: Introduction: Tuberculosis (TB), primarily caused by Mycobacterium tuberculosis, remains a major global health threat, further intensified by the emergence of drug-resistant strains. Rapid molecular diagnostic tools such as the GeneXpert MTB/RIF assay have significantly improved early detection of TB and identification of rifampicin resistance, offering faster and more accurate results than conventional methods.

Aim: To compare smear microscopy with the GeneXpert MTB/RIF assay for the rapid detection of Mycobacterium tuberculosis and simultaneous detection of rifampicin resistance.

Materials and Methods: A cross-sectional study was conducted over one year (September 2022 to September 2023) at Geetanjali Medical College and Hospital, Udaipur, Rajasthan, India. A total of 314 clinical specimens (233 pulmonary and 81 extrapulmonary) were tested using both Ziehl–Neelsen (ZN) staining and the GeneXpert MTB/RIF assay. Specimens were processed according to standard protocols for both diagnostic methods. Demographic details such as age and gender were recorded. Statistical analysis was performed using the Chi-square test, with a p-value <0.001 was considered statistically significant.

Results: Among the 314 samples, males constituted the majority (204; 65%), and the most affected age group was 51-70 years (133; 42.36%). Using GeneXpert, 87 (27.7%) samples tested positive for M. tuberculosis, whereas smear microscopy detected only 60 (19.1%). Among pulmonary samples (n=233), GeneXpert detected MTB in 81 (35%) cases, while smear microscopy detected 58 (25%). Among extrapulmonary samples (n=81), GeneXpert detected MTB in 6 (7%) cases, whereas smear microscopy detected only 1 (1%). Of the total samples, 59 (19%) were positive by both methods, 28 (9%) were positive only by GeneXpert, and 1 (0.3%) sample was positive only by smear. GeneXpert demonstrated a 6% higher diagnostic yield for extrapulmonary TB compared with smear microscopy. Rifampicin resistance was identified in 10 (11%) of the 87 GeneXpert-positive samples, indicating the presence of potential multidrug-resistant TB.

Conclusion: The GeneXpert MTB/RIF assay is more sensitive than smear microscopy for detecting MTB in both pulmonary and extrapulmonary samples. It enables rapid diagnosis and simultaneous detection of rifampicin resistance, which is essential for the timely initiation of appropriate therapy.
Keywords : Antitubercular agents, Diagnosis, Multidrug-resistant acid amplification techniques, Rifampin
DOI and Others : DOI: 10.7860/NJLM/2026/81374.2951 Date of Submission: Jun 18, 2025 Date of Peer Review: Sep 23, 2025 Date of Acceptance: Nov 06, 2025 Date of Publishing: Jan 01, 2026 AUTHOR DECLARATION: • Financial or Other Competing Interests: None • Was Ethics Committee Approval obtained for this study? Yes • Was informed consent obtained from the subjects involved in the study? NA • For any images presented appropriate consent has been obtained from the subjects. NA PLAGIARISM CHECKING METHODS: • Plagiarism X-checker: Aug 29, 2025 • Manual Googling: Oct 31, 2025 • iThenticate Software: Nov 05, 2025 (12%) ETYMOLOGY: Author Origin EMENDATIONS: 7
 
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