Applications of polymerase chain reaction-based methods for the diagnosis of plague (Review)

Abstract

Plague is an acute bacterial infection caused by Yersinia pestis. The three major clinical forms of plague are bubonic, pneumonic and septicemic, which have high case-mortality rates. Therefore, rapid and reliable diagnostic tools are crucial. Currently, bacteriological means and traditional serological assays are used for detecting infection with Y. pestis. However, such methods have their limitations. Polymerase chain reaction (PCR) is one of the most useful tools for rapid diagnosis of plague. The present review introduced the main PCR techniques and their applications for detecting and confirmation of Y. pestis. The advantages and disadvantages of the different PCR methods were also summarized.

Keywords: Yersinia pestis; molecular diagnosis; plague; polymerase chain reaction techniques.

Figure 1

Transmission routes of plague. Rodents act as hosts and reservoirs for Y. pestis, vectored by fleas. Mammals, which are not the natural hosts of Y. pestis, may become infected via the bite of an infected flea. Infection may be transmitted to humans through flea bites or through direct contact with infected animals.

Figure 2

Algorithm for the molecular biology tests of plague. DNA confirmation on the presence of Y. pestis in human specimens is performed using quantitative PCR targeting pla and caf1 and in the case of discordant or uncertain results, a conventional PCR targeting pla, caf1 and inv is performed. pla, plasminogen activator gene; caf1, 60-Md plasmid-located gene; inv, invasin protein gene.