Utility of GeneXpert in Diagnosis of Pediatric Tuberculosis and Detection of Rifampicin Resistance

Abstract Background : Tuberculosis (TB) remains a significant public health challenge in developing countries, including India, where children under 15 years account for 12% of all TB cases. The National Tuberculosis Elimination Programme (NTEP) recommends the use of GeneXpert/Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) for TB diagnosis, followed by Line Probe Assay (LPA) for detecting drug resistance. This study aimed to determine the prevalence of TB and rifampicin resistance in pediatric patients and to evaluate the utility of CBNAAT in comparison with LPA and Ziehl-Neelsen staining. Methods : This retrospective study was conducted over one year, from 1st January 2022 to 31st December 2022, at a tertiary care hospital in western Maharashtra. A total of 528 samples from pediatric patients (aged <18 years) suspected of having TB were included. Samples underwent CBNAAT testing and Ziehl-Neelsen staining. Positive samples were further analyzed using LPA or Mycobacterial Growth Indicator Tube (MGIT) culture. Results : Among the 528 samples analyzed, gastric lavage accounted for 81.25% of the specimens. CBNAAT detected TB in 61 (11.55%) of the samples, with 15 (24.59%) of these showing rifampicin resistance. Samples with very low or low bacterial loads were often missed by Ziehl-Neelsen staining. Conclusion : Pediatric tuberculosis continues to be a public health concern in developing countries. The study found an 11.55% positivity rate in children under 18 years of age, with 24.59% of positive cases exhibiting rifampicin resistance. The findings underscore the importance of using advanced diagnostic techniques like CBNAAT and highlight the limitations of Ziehl-Neelsen staining in detecting low bacterial loads.