This study aims to conduct an international study involving laboratories participating in the leprosy diagnosis all over the world aiming at sharing a pilot external quality assessment (EQA) scheme for microbial diagnosis of leprosy and drug susceptibility testing (DST).
Setting an external quality assessment (EQA) programme for enhancing capacity building focusing to the microbiological tools used in the diagnosis of leprosy and the detection of drug resistance
Project coordination
- French National reference center for mycobacteria
Project summary
Diagnosis of leprosy needs to be improved in many places of the world since transmission is ongoing with new child cases every year and there are no sharp decrease in the new cases and incidence. Although clinical signs and examination of the patient are often sufficient to diagnose a new case, microbiological diagnosis is helpful for cases difficult to diagnose or to treat, especially in relapse cases, and in areas where expertise in leprosy is deficient. In addition, detection and surveillance of resistance to antileprosy drugs is now mandatory for all endemic countries for retreated cases as well as a part of new cases.
Research questions: Microbial diagnosis of leprosy and molecular detection of resistance to antileprosy drugs is done using analysis tools such as microscopy, detection of Mycobacterium leprae DNA, detection of mutations conferring resistance. These microbiological tools are implemented in many endemic regions, but they are mostly following in house protocols (no commercially available kits in most places), they are rarely standardised and never evaluated for their reliability. This project will organise a pilot external quality assessment (EQA) to compare results of leprosy labs when performed of identical samples.
Plan of investigation: The research group's lab, which is one of the supranational reference labs for surveillance of drug resistance, will prepare some tissue samples containing (positive samples) or not (negative samples) M. leprae. Since this bacteria cannot multiply in vitro, and because human skin biopsies will not be used, the researchers will take samples of animals infected with M. leprae, the classical one being the mouse model where M. leprae grows in their footpads. These samples will be shipped to diagnostics labs located in leprosy endemic regions and who are involved with routine leprosy diagnosis. These labs will also, in return, send to the research group's lab some (randomly chosen) of the skin samples they received from leprosy cases in their area for diagnosis purposes. The researchers will compare all the results obtained by the laboratories on the same sample: those with more than 80% of concordant test results will get a EQA certificate; those with under 80% concordance will be invited for a second EQA round and workshop meetings in order to improve their technical skills and succeed on the second EQA year. All the samples studied from the endemic regions labs will be used to draw a map of diagnosis capacity and drug resistance rates certified by microbiological laboratories. This will help the managers and the authorities to involve these labs in the projects on elimination of leprosy and surveillance of resistance to antileprosy drugs.