Measuring the Rate of Isoniazid Mono-Resistance in Mycobacterium Tuberculosis in Kazakhstan

DESCRIPTION: Kazakhstan has an overall tuberculosis incidence rate of 67 per 100,000 population, and is classified as a high MDR TB burden country – 26% of new cases and 44% of retreatment cases are multidrug-resistant. Kazakhstan is also the major destination for migrants from other countries in Central Asia, who, along with incarcerated populations, are at particularly high risk of TB and MDR TB. The government places TB control at a high priority, and given the growing burden, new insight into drug resistance and development of new disease surveillance methods has great potential to reduce TB morbidity and mortality in Kazakhstan.

Part of preventing the advance of MDR TB is ensuring that all patients with drug susceptible strains of TB are properly treated with the appropriate drugs; this reduces the likelihood of resistance developing during treatment, retreatment or after relapse. For instance, patients with rifampicin susceptible and isoniazid (INH) resistant TB, must be given treatment regimens which exclude isoniazid – failure to do this may encourage amplification of resistance and perhaps development of MDR TB. Resistance to isoniazid is often overlooked, and cases are assumed susceptible if rifampicin susceptibility is confirmed. Mono-resistance to isoniazid however, is thought to affect 9.5% of all TB cases, and 14% of retreatment cases, indicating that confirming INH susceptibility may result in important treatment or retreatment decisions. Prevalence of INH mono-resistance in Kazakhstan and in Central Asia generally is not well documented. The primary purpose of this study will be to improve our understanding of INH mono-resistance in Kazakhstan.