Creating standards for absolute quantification of Coxiella burnetii in real-time PCR--a comparative study based on transmission electron microscopy.

Quantitative standards are a prerequisite for quality control and quantification of pathogens. In this study the creation of quantitative standards for use in qPCR is described using the pathogen Coxiella burnetii. Quantification of Coxiella burnetii particles by transmission electron microscopy (TEM) was used as primary standard and compared with data obtained by light microscopy as well as genome equivalents (GE) and plasmid units (recombinant plasmid).