Plague Diagnosis STNPCR and MPCR Kits Assembly, Reaction Reproducibility, and Reagent Stability

Abstract

Plague (Yersinia pestis infection) can constitute an international public health emergency, requiring notification of the World Health Organization (WHO) under the International Health Regulations (IHR). To comply with the IHR and to prevent the spread of the disease, rapid, accurate, and efficient diagnosis is necessary. In this work, we carried out studies on two diagnostic tests: single-tube nested PCR (STNPCR) and multiplex PCR (MPCR). These tests allow the discrimination of Y. pestis strains based on the presence or absence of known pathogenicity markers. Two versions of each test were produced: (1) consists of a set of tubes containing premixed reagents for one reaction; (2) consists of a pool of reagents for 10 reactions. The reproducibility of the reactions and stability of the reagents were also evaluated under time and storage conditions. Both versions of the kits were shown to be stable during a 12-month evaluation period of storage at −20°C. The DNA detection limit after 12 months of storage at −20°C was 10 pg for both versions of the STNPCR and MPCR kits. Finally, we simulated two shipment conditions for the version 1 of the kits with liquid reagents in dry ice and also with freeze-dried reagents at room temperature (RT). Liquid kits were viable and produced the expected amplification results after 4 days in dry ice and freeze-dried kits can be shipped at RT over a time period of 30 days. The use of the preformulated test tubes evaluated in the present study could reduce errors in the reaction preparation and improves the efficiency of plague monitoring and control programs.