Development of a new TaqMan-based PCR assay for the specific detection and quantification of Simkania negevensis

Simkania negevensis is an emerging Chlamydia-like bacterium related to human respiratory diseases. An early and accurate detection of this pathogen could be useful to monitor the potential infectious risks and to set suitable outbreak control measures. In Tunisia, distribution and abundance of S. negevensis remain until now largely unknown. In the present work, a qPCR assay, targeting the 16S rRNA gene, for fast detection and quantification of S. negevensis was developed and validated. A high specificity for S. negevensis detection displaying no cross-reaction with the closely related Chlamydia spp. or the other tested microorganisms was noticed. qPCR assay performance was considered very satisfying with detection limits of 5 DNA copies per reaction. qPCR assay validation was performed by screening 37 clinical specimens and 35 water samples. S. negevensis wasn't detected in respiratory samples, but it was found in four cases of water samples. We suggest that the qPCR assay developed in this study could be considered sufficiently characterized to initiate the quantification of S. negevensis in environmental samples.