Multi-centric evaluation of Biomeme Franklin Mobile qPCR for rapid detection of Mycobacterium ulcerans in clinical specimens

The gold standard for detection of Mycobacterium ulcerans is PCR due to its high accuracy in confirmation of suspected cases. But the available PCR assays are designed for standard size thermocyclers which are immobile and suited for reference laboratories often located long distances from endemic communities. This makes it a challenge to obtain immediate results for patient management. We validated and evaluated a dried reagent-based PCR assay adapted for a handheld, battery-operated, portable thermocycler with the potential to extend diagnostics to endemic communities with limited infrastructure. The diagnostic accuracy of the assay following a multi-center evaluation by three Buruli ulcer reference laboratories with over 300 clinical samples showed sensitivity and specificity of 100-97% and 100-94%, respectively using centralized IS2404 quantitative PCR platform as a reference standard. This assay coupled with a field-friendly extraction method fulfill almost all the target product profiles of Buruli ulcer for decentralized testing at the district, health center and community levels; a key critical action for achieving the NTD Road Map 2030 target for Buruli ulcer. Author summaryEarly diagnosis of Buruli ulcer remains a major problem in many endemic countries particularly in sub-Saharan Africa which continues to report large wounds as a result. Though reference laboratories with capacity to confirm diagnosis of the disease by recommended PCR method are available in most endemic countries, they are often located long distances from endemic communities and treatment centres. This makes it a challenge to obtain immediate results for patient management. There is therefore the need to have innovative diagnostic tools that can be fully implemented in local health facilities but not compromising accuracy. We have evaluated a diagnostic tool with accuracy like the recommended method with the potential to be used in health facilities closer to the patients.

Automated summary

The gold standard for detection of Mycobacterium ulcerans is PCR, but the available PCR assays are not suitable for use in endemic communities due to a lack of mobility. We validated a dried reagent-based PCR assay for use with a portable thermocycler that could be used in communities with limited infrastructure. The assay showed high sensitivity and specificity, making it a suitable decentralized testing option for Buruli ulcer.