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Management of isoniazid-monoresistant tuberculosis (Hr-TB) in Queensland, Australia: a retrospective case series

Wilson M, O'Connor B, Matigian N, Eather G

Respiratory medicine, 2020

7 citations

Abstract

OBJECTIVES

Drug-resistance represents a major threat in the fight against tuberculosis. Globally, isoniazid-monoresistant tuberculosis (Hr-TB) is twice as common as multidrug/rifampicin-resistant (MDR/RR)-TB. Recently updated WHO guidelines now recommend treatment of Hr-TB with rifampicin, ethambutol, pyrazinamide and levofloxacin for at least six months. Our primary objective was to define the frequency, treatment and outcomes for Hr-TB in Queensland, Australia. We also sought to determine the frequency of fluoroquinolone use and whether its inclusion improved outcomes.

METHODS

Retrospective case series of tuberculosis notifications in Queensland between 2000 and 2017 with at least low-level isoniazid resistance and preserved susceptibility to other first-line oral agents.

RESULTS

Hr-TB was identified in 7.2% of all notifications. Where outcomes were assessable (163/198), 76.1% were treated with first-line agents only and 11.0% received at least six months of a fluoroquinolone-containing regimen (consistent with recent WHO guidelines). Favourable outcomes were achieved in 95.7%, comparable to fully susceptible disease (94.9%). Inclusion of a fluoroquinolone did not significantly improve outcomes compared with a regimen containing first-line agents only, although these cases were more likely to have high-level resistance. Previous treatment made an unfavourable outcome more likely.

CONCLUSIONS

Hr-TB is prevalent in Queensland. Treatment outcomes in our cohort were comparable…

How strong is the evidence?

Evidence Hub reads this as a case series, done in people. Its evidence level is 5 of 5 (Very low · case / narrative / animal / in vitro / in silico). Case reports, narrative reviews, and animal, cell or computer-model studies give the weakest evidence for human health.

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