# Retrospective epidemiological analysis of pulmonary tuberculosis in the older adult and characterization of rifampicin resistance-associated rpoB mutations in Nantong City, China (2014–2023)

## TL;DR

This study examines the decline in older adult pulmonary tuberculosis cases and analyzes rifampicin resistance mutations in Nantong, China, from 2014 to 2023.

## Contribution

The study provides new insights into the epidemiological trends and rpoB mutation patterns in older adults with rifampicin-resistant tuberculosis in Nantong.

## Key findings

- The standardized incidence of older adult pulmonary tuberculosis in Nantong declined rapidly and stabilized from 2014 to 2023.
- Single-gene rpoB mutations were the most common in rifampicin-resistant older adult patients.
- Treatment outcomes were significantly associated with rifampicin resistance and initial diagnostic test results.

## Abstract

To analyze the prevalence trend of older adult pulmonary tuberculosis (ETB) and the distribution and outcome of rifampicin-resistant rpoB gene mutation in ETB patients in Nantong.

The pulmonary tuberculosis patients’ data in Nantong from 2014 to 2023 were from Tuberculosis Information Management Syste and ETB and rifampicin-resistant rpoB mutation patients were retrospectively analyzed.

From 2014 to 2023, the overall standardized incidence of ETB in Nantong showed a trend of rapid decline and tended to a stable trend stabilized. A total of 140 older adult patients with rifampin resistance, aged 60–69 years, 87 cases (62.1%). single-gene mutation Probe E mutations were the most frequent, observed in 39 cases (60.0%). Specifically, 52 cases (80.00%) were resistant to rifampicin, and Probe E of 31 cases (59.62%) showed the most mutations. The outcome of ETB patients with rifampicin resistance were significantly correlated with treatment classification, rifampicin resistance, Xpert MTB first test, and 0-month sequential sputum positivity.

The number of ETB in Nantong from 2014 to 2023 showed a rapid decline and stabilized. The rpoB mutations in the ETB rifampicin-resistant patients were mainly single-gene mutations. The authorities should formulate effective regional prevention and control measures based on the characteristics of the ETB rifampicin-resistant patients.