Drug Resistant Survey (DRS)

Tuberculosis (TB) in Zambia continues to be one of the major causes of morbidity and mortality. Despite fairly good treatment success rates for drug susceptible TB (DS-TB), Drug Resistant TB (DR-TB) has continued to be a growing problem in Zambia. In settings without capacity for continuous surveillance based on routine drug susceptibility testing of new TB cases, it is recommended that a national survey should be conducted at least every 5 years. The 2019-2020 Tuberculosis Drug Resistance survey (TB DRS) is in line with National Tuberculosis Programme (NTP) 2017 – 2021 National Tuberculosis Strategic Plan goal and objectives which sets the pace towards elimination of TB in Zambia. To achieve this aim, it is important to understand the true burden and distribution of drug-resistant TB in Zambia by carrying out a national drug-resistance survey.
2019-2020 National TB DRS is third to be conducted with the goal to determine the current prevalence of anti-tuberculosis drug resistance in Zambia.
Study Objectives
The objectives of the current survey include: to determine the proportions and patterns of drug resistance to fluoroquinolones and second-line injectable agents (with focus on Amikacin and streptomycin) among patients with confirmed MDR-TB (TB resistant to Rifampicin and Isoniazid); to determine the associations between drug resistance and socio-demographic or clinical characteristics such as age, sex, or HIV status; to describe drug resistance trends over time compared to the 2001 and 2008 DRS; to determine concordance between phenotypic TB drug susceptibility testing and LPA; and to conduct whole genome sequencing on any case of drug resistant TB in order to find additional genetic mutations.
The first TB DRS was conducted in 2000 and the second one in 2008. Zambart won a contract to conduct 2019-2020 TB DRS in April 2019.
Methodology
Ministry of Health provided a list of all diagnostic centres and a 2-stage weighted cluster sampling was conducted. The Primary Sampling Unit was diagnostic health facility, and the Secondary Sampling Unit was individual bacteriologically-confirmed TB patients. A total of 50 clusters from 47 diagnostic centres were randomly selected from all ten provinces and 33 districts across Zambia. Meaning three diagnostic centres has two clusters each. Each cluster is expected to recruit 22 consecutive bacteriologically confirmed sputum positive TB patients. A target of 1,100 participants is to be recruited by September 30th, 2020.
The first training in survey implementation activities will conducted in Lusaka Province and five diagnostic centres were trained from 23-24 September 2019. All 49 diagnostic centres will be trained by December 2019, and a total 190 Ministry of Health staff will be trained during the same period. The first participant is expected to be recruited by September 2019.