[Patterns of resistance to anti-tuberculosis drugs among patients with rifampicin-resistant pulmonary tuberculosis in Yaoundé, Cameroon].

INTRODUCTION

Screening for multidrug-resistant pulmonary tuberculosis (MDR-PTB) by using the Xpert MTB/ RIF test to detect rifampicin resistance as a surrogate marker for this form of tuberculosis may lead to suboptimal treatment if resistance to other drugs in the treatment regimen is not also determined. The objective of this study was to analyze the patterns of drug resistance to anti-tuberculosis drugs in patients with rifampicin-resistant pulmonary tuberculosis (RR-PTB) who were treated with the standardized 9-11-month regimen in Yaoundé, Cameroon.

MATERIALS AND

METHODS

This retrospective, cross-sectional study examined the results of anti-tuberculosis drug susceptibility tests in RR-PTB patients who received the standardized 9-11-month treatment regimen at the specialized MDR-PTB treatment center of the Jamot Hospital in Yaoundé from 2013 to 2022.

RESULTS

A total of 322 RR-PTB patients were included in the study. Of these, 281 (87.3%) were resistant to at least one of the tested drugs. The pattern of resistance was 43.2% for one drug, 41.6% for two drugs, and 2.5% for three or more drugs. Resistance to isoniazid was the most common (87.3%), followed by ethambutol (42.2%), fluoroquinolones (3.4%), and amikacin (1.9%).

DISCUSSION –

CONCLUSION

The majority of RR-PTB patients in Yaoundé had MDR-PTB, and pre-extensively drug-resistant TB was rare. However, the GeneXpert-based strategy for identifying drug-resistant cases (which detects only rifampicin resistance) could lead to the initiation of suboptimal treatment for a non-negligible proportion of patients in our setting. This could result in the amplification of resistance and the transmission of increasingly resistant strains within the community. We recommend that the National Tuberculosis Control Program (NTCP) of Cameroon should adopt and rapidly roll out the new short-course treatment regimen recommended by the World Health Organization given the lack of rapid tests in our country capable of detecting resistance to the various drugs used in the standard 9-11-month regimen.