Researchers from Wageningen University (Netherlands) and Institute of Microbiology of Munich (Germany), assessed the viability of C. burnetii in two different in vitro culturing systems (cell-based and cell-free systems). The authors used PhAST Blue equipment to evaluate viability PCR technology. Results obtained by viability PCR were similar to those obtained by direct enumeration FFU and CFU assays, showing the suitability of PMA-PCR method for enumeration of viable C. burnetii.