Prevalence of Rifampicin-Resistant Tuberculosis in presumptive Tuberculosis Patients attending tertiary care hospitals in Colombo, Sri Lanka

Abstract

Introduction: Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), remains a major global health threat. The advent of rifampicin-resistant TB (RR-TB) poses significant challenges in TB management. This study aims to determine the prevalence and distribution of MTB and RR-TB using the Xpert MTB/RIF assay, in various clinical samples referred from tertiary care hospitals in Sri Lanka.

Methodology: A retrospective analysis was conducted on laboratory data from May 2021 to May 2024. Samples  received from state hospitals and clinics were analyzed using the Xpert MTB/RIF-assay from May 2021 to July 2023 and the Xpert MTB/RIF Ultra from August 2023 to May 2024 to detect MTB and Rifampicin resistance. Data on sample types, patient demographics, and MTB/RR-TB detection rates were collected and analyzed using descriptive statistics.

Results: A total of 7457 samples were received from Teaching Hospitals between May 2021 and May 2024 from patients  with suspected TB. Of the samples 794 (10.65%) were MTB positive, of which 487 (61.34%) were from male patients and  307 (38.66%) from females.  Patients aged 25 - 64 years had the highest number of positive MTB results (n=517, 65.11%). The highest number of positive samples were sputum (n=651, 13.16%) but the highest detection rate was seen in tissue biopsies (n=43, 16.54%). Of the 794 positive samples, Rifampicin resistance was detected in 13 (1.64%), while Rifampicin Sensitivity was seen in 719 (90.55%) and indeterminate results in 62 (7.80%). RR-TB was predominantly seen in sputum samples (n=7, 1.08%), with tissue biopsies showing the highest proportion (n=4, 9.30%). 

Conclusion:The study reveals a relatively low prevalence of RR-TB in Sri Lanka, likely to be due to effective National TB control programs and public health strategies. The high detection rates in tissue biopsies and significant presence of RR-TB in sputum samples emphasize the need for vigilant TB management and tailored interventions to address drug resistance.