A diagnostic study of pulmonary and extra pulmonary tuberculosis by GeneXpert MTB/RIF assay in pediatric population

Pediatric tuberculosis is an important subset of tuberculosis infection burden with a high detection gap due to paucibacillary nature. GeneXpert MTB/RIF assay detects rifampicin resistant (RR) Mycobacterium tuberculosis (MTB) that provides bacillary load and mutation/probe details. The present study aimed to study the frequency of pulmonary and extrapulmonary tuberculosis (TB) and rifampicin resistance (RR) in relation to bacillary load, age and gender in pediatric patients, at tertiary care referral center.

In the present study 5110 patients were screened for tuberculosis using GeneXpert MTB/RIF assay as routine test. The data was then searched retrospectively for pediatric tuberculosis patients of age up to 18 years. Out of these, a total 970 (18.98 %) were identified as presumptive pediatric TB patients.

The data showed MTB positivity to be 38.1 % (370/970) and RR-TB to be 5.2 % (51/970) among presumptive pediatric TB patients. Females made up 60.3 % (585/970) of presumptive cases with a higher positivity rate [44.4 % (260/585) Vs. 28.5 % (110/385)] and were 2 times more likely to have TB compared to males (OR = 2.00, 95 % CI = 1.520-2.632, p = 0.0001). Age groups of 11-15 years and 16-18 years were respectively 4.903 (OR = 4.903, 95 % CI = 2.523-9.530, p = 0.0001) and 7.043 (OR = 7.043, 95 % CI = 3.957-13.971, p = 0.001) times more likely to develop TB as compared to those of age 0-5 years. Samples with a high bacillary load showed a significant correlation with RR-TB incidence and Probe E negative results (p = 0.0001, p = 0.048).

Among pediatric population females are at a higher risk of developing TB and need specific intervention. The children with age group 11-15 and 16-18 years are more likely to have MTB positive finding than 0-5 years old. This study highlights a high percentage of mutations in the probe E region (86.2 %, 44/51).