Criblamydia sequanensis, a new intracellular Chlamydiales isolated from Seine river water using amoebal co‐culture

Abstract

Accumulating evidence supports a role for Chlamydia-related organisms as emerging pathogens for human and animals. Assessment of their pathogenicity requires strain availability, at least for animal models and serological studies. As these obligate intracellular species are able to grow inside amoebae, we used co-culture with Acanthamoeba castellanii in an attempt to recover new Chlamydia-related species from river water. We isolated two strains from eight water samples. The first strain is a new Parachlamydia acanthamoebae strain that differs from previously described isolates by only two bases in the complete 16S rRNA gene sequence. The second isolate is the first representative of a new Chlamydiales family, as demonstrated by genetic and phylogenetic analyses of the 16S rRNA, 23S rRNA, ADP/ATP translocase and RnpB encoding genes. Using fluorescent in situ hybridization and electron microscopy, we demonstrated that it grows in high numbers in amoebae, where it exhibits a Chlamydia-like developmental cycle with reticulate bodies and star-like elementary bodies. Based on these results, we propose to name this new species 'Criblamydia sequanensis'. This work confirmed that amoebal co-culture is a relevant method to isolate new chlamydiae, and that it can be successfully applied to ecosystems colonized with a complex microbial community.

Simkania negevensis, an insight into the biology and clinical importance of a novel member of the Chlamydiales order

“…As an example, crescent bodies and star bodies were reported as infectious EB-like particles of Parachlamydiaceae and Criblamydiaceae, respectively (Lienard et al, 2011b;Thomas et al, 2006). Current knowledge suggests that these observations are largely influenced by the buffer and the fixatives used and therefore do not allow taxonomic discrimination, even if they correspond to some structural differences in the cell wall of the different bacterial families (Pilhofer et al, 2014;.…”

Evidence of Maternal–Fetal Transmission ofParachlamydia acanthamoebae

“…These primers did not allow amplifi cation of partial rpoB gene for the 6 M. phocaicum strains. We thus used Myco-F/Myco-Rbon (5′-AGCGGCTGCTGGGTGATCAT-3′) primer pair for M. phocaicum (8). We compared these sequences with the rpoB gene sequence of Mycobacteria type strains available in the GeneBank database by using BLASTn on the NCBI website (www.ncbi.nlm.nih.…”

New Diagnostic Real-Time PCR for Specific Detection of Parachlamydia acanthamoebae DNA in Clinical Samples

“…For these reasons, molecular diagnostic approaches are warranted. Broad-range PCR assays for the members of the Chlamydiales, which include P. acanthamoebae, have been described (8,18), but their sensitivities are limited. An additional sequencing step is required, which is directly achievable (without cloning) only for samples containing a minimum of 1,000 DNA copies (G. Greub et al, unpublished data).…”