Global availability of susceptibility testing for second-line anti-tuberculosis agents.

The continued development of new anti-TB agents brings with it a demand for accompanying treatment regimens to prevent the development of resistance. Effectively meeting this demand requires an understanding of the pathogen´s susceptibility to various treatment options, which in turn makes access to antibiotic susceptibility testing (AST) a paramount consideration in the global treatment of TB. A 12-question, quantitative and qualitative survey was developed to gauge global capacity and access to AST. The survey was disseminated to members of the Global Laboratory Initiative, Global Drug-resistant TB Initiative, and the TB section of the International Union Against Tuberculosis and Lung Disease to solicit responses from pertinent stakeholders. A total of 323 complete responses representing 84 countries and all WHO Regions were collected. AST capacity for fluoroquinolones and second-line injectables was high in all WHO Regions. AST capacity for the new and repurposed drugs is highest in the European Region, Region of the Americas and the Western Pacific Region, but quite limited in the African and Eastern Mediterranean Regions. The AST turnaround time for second-line drugs was delayed compared to that for first-line drugs as samples needed to be sent farther for analysis. Common barriers to AST for second-line drugs were lack of specimen transportation infrastructure, high costs, and lack of specialised laboratory workers and specialised laboratory facilities. Without expanding global access to AST, the growing availability of new treatment options will likely be threatened by accompanying increase in resistance. There is an earnest and pressing need to improve capacity and access to AST alongside treatment options.