Evaluation of quantitative FTD-Pneumocystis jirovecii kit for Pneumocystis infection diagnosis

- The commercial FTD Pneumocystis PCR is a suitable alternative method for the diagnosis of Pneumocystis infections.
- Lower and upper cut-off values of 3.9×105 copies/ml and 3.2×106 copies/ml allowed differentiating PCP and colonization in bronchoalveolar lavage fluids specimens, when using FTD Pneumocystis PCR.
- This study reports, to the best of our knowledge the first data of P. jirovecii infections in Réunion Island.

We evaluated the Fast track Diagnostics (FTD) Pneumocystis PCR kit, targeting the mitochondrial large subunit ribosomal RNA gene (mtLSU rRNA) of Pneumocystis jirovecii (P. jirovecii). A hundred and thirty-three patients were prospectively enrolled. Respiratory specimens were examined using both microscopy and the PCR assay. Twenty-six patients led to P. jirovecii detection. Fourteen patients presented with Pneumocystis pneumonia (PCP) whereas 12 patients were considered to be colonized. The median copy numbers in bronchoalveolar lavage fluid were significantly different in the PCP and colonization groups (1.35×108/ml vs. 1.45×105/ml, P < 0.0001). Lower and upper cut-off values of 3.9×105 copies/ml and 3.2×106 copies/ml allowed differentiating PCP and colonization. The FTD P. jirovecii assay was secondarily compared to an in-house reference PCR assay targeting the mtLSUrRNA gene. A concordance rate of 97.5% was observed (Cohen's kappa coefficient κ=0.935). The FTD Pneumocystis PCR kit showed good performance and represents an alternative method to diagnose P. jirovecii infections.