Drug susceptibility patterns of Mycobacterium tuberculosis from adults with multidrug-resistant tuberculosis and implications for a household contact preventive therapy trial
Date
2021-02-24
Journal Title
Journal ISSN
Volume Title
Publisher
BMC (part of Springer Nature)
Abstract
Background: Drug susceptibility testing (DST) patterns of Mycobacterium tuberculosis (MTB) from patients with
rifampicin-resistant tuberculosis (RR-TB) or multidrug-resistant TB (MDR-TB; or resistant to rifampicin and isoniazid
(INH)), are important to guide preventive therapy for their household contacts (HHCs).
Methods: As part of a feasibility study done in preparation for an MDR-TB preventive therapy trial in HHCs, smear,
Xpert MTB/RIF, Hain MTBDRplus, culture and DST results of index MDR-TB patients were obtained from routine TB
programs. A sputum sample was collected at study entry and evaluated by the same tests. Not all tests were
performed on all specimens due to variations in test availability.
Results: Three hundred eight adults with reported RR/MDR-TB were enrolled from 16 participating sites in 8
countries. Their median age was 36 years, and 36% were HIV-infected. Routine testing on all 308 were confirmed as
having RR-TB, but only 75% were documented as having MDR-TB. The majority of those not classified as having
MDR-TB were because only rifampicin resistance was tested. At study entry (median 59 days after MDR-TB
treatment initiation), 280 participants (91%) were able to produce sputum for the study, of whom 147 (53%) still
had detectable MTB. All but 2 of these 147 had rifampicin DST done, with resistance detected in 89%. Almost half
(47%) of the 147 specimens had INH DST done, with 83% resistance. Therefore, 20% of the 280 study specimens
had MDR-TB confirmed. Overall, DST for second-line drugs were available in only 35% of the 308 routine specimens
and 15% of 280 study specimens.
Conclusions: RR-TB was detected in all routine specimens but only 75% had documented MDR-TB, illustrating the
need for expanded DST beyond Xpert MTB/RIF to target preventive therapy for HHC.
Description
Demers, A. M., et al. 2021. Drug susceptibility patterns of Mycobacterium tuberculosis from adults with multidrug-resistant tuberculosis and implications for a household contact preventive therapy trial. BMC Infectious Diseases, 21:205, doi:10.1186/s12879-021-05884-4
Keywords
Tuberculosis, Drug resistance, Antimicrobial susceptibility testing, Mycobacterium tuberculosis