Sequencing and molecular typing of hypervariable loci in the Treponema pallidum genomes: characterisations of type strains and clinical isolates
Abstract number: P1704
Smajs D., Matejkova P., Strouhal M., Woznicova V., Weinstock G.M.
Objectives: Using Comparative Genomic Sequencing (CGS) approach, hypervariable regions in Treponema pallidum genome were identified. These regions comprised hypothetical genes TP0136 and TP0548. Nucleotide sequences of these genes were determined and compared in 4 groups of T. pallidum strains: in ssp. pallidum (6 strains causing syphilis), in ssp. pertenue (6 strains causing yaws), in ssp. endemicum (2 strains causing endemic syphilis) and in 1 strain of unclassified simian isolate. In addition, 9 PCR positive clinical samples were analysed.
Methods: Primary screening of clinical specimens was performed using nested PCR detection of two T. pallidum specific loci (tmpC, polA). In PCR positive samples, direct Sanger sequencing of TP0136 and TP0548 PCR products was used to determine the corresponding sequences. Sequencing reads were analysed using computer-assisted assembly and the final nucleotide and protein sequences were clustered.
Results: The TP0136 and TP0548 analysed loci showed discrete clusters in 4 groups of type strains. Analysis of strains belonging to ssp. pallidum revealed two discrete subclusters containing Nichols-like and SS14-like sequences, respectively. All clinical isolates clustered with the SS14-like subgroup. In 4 clinical isolates, unique sequences in either TP0136 or TP0548 were found. Sequencing of different samples obtained from the same patient resulted in identical sequences.
Conclusions: Our results showed that TP0136 and TP0548 loci represent promising targets for molecular typing of pathogenic treponemes including clinical samples.
This work was supported by the grants from the Internal Grant Agency of the Ministry of Health of the Czech Republic (NR/89674/2006) and from the Grant Agency of the Czech Republic (310/07/0321).
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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