Prevalence and Rifampicin Resistance Patterns in Extrapulmonary Tuberculosis at a Tertiary Care Centre in Western Maharashtra

Background: Tuberculosis remains a major public health problem in India. Extrapulmonary tuberculosis (EPTB) poses considerable diagnostic challenges because of its paucibacillary nature and non-specific clinical presentation. Molecular diagnostic tools such as CBNAAT (Cartridge-Based Nucleic Acid Amplification Test) have improved detection rates in resource-limited settings. Objectives: To determine the prevalence of EPTB and rifampicin resistance among EPTB-positive cases. Methods: A laboratory-based descriptive cross-sectional study was conducted from January to December 2023 at the CBNAAT laboratory of a tertiary care teaching hospital in western Maharashtra. A total of 1419 extrapulmonary specimens were tested using the GeneXpert MTBRIF assay (Cepheid, USA). Data were extracted from the GeneXpert software and analysed descriptively using SPSS version 22. Frequencies and percentages were calculated for categorical variables. Results: Mycobacterium tuberculosis (Mtb) was detected in 119 of 1419 (8.39) extrapulmonary samples. Rifampicin resistance was found in 8 of 119 (6.72) EPTB-positive isolates. Lymph nodes were the most commonly affected site (30.25), followed by pusabscess (25.21) and pleural fluid (17.65). Over 80 of EPTB cases demonstrated low or very low bacterial loads on semi-quantitative assessment. Conclusion: EPTB positivity is lower than pulmonary TB positivity. Lymphadenopathy constitutes the most common form of EPTB. Rifampicin resistance was detected in a notable proportion of EPTB-positive cases. The predominantly paucibacillary nature of EPTB continues to pose diagnostic difficulties.