Mamuka Kotetishvili
The University of Georgia, Georgia
Title: A unique strain of Clostridium tetani, isolated from a retail fish market in India, carries in its genome a 1176-bp region being highly homologous to 18S ribosomal RNA loci of eukaryotic origin
Biography
Biography: Mamuka Kotetishvili
Abstract
Statement of the Problem: The deciphering of new genomic features of Clostridium tetani causing tetanus is critical to our better understanding of this disease molecular epidemiology, threatening especially neonates and children. Here, we report on a unique C. tetani strain isolated from a retail fish market in India, carrying in its genome the eukaryotic DNA. Methodology & Theoretical Orientation: This strain genome sequence (GenBank ID: CP027782.1) was available in the National Center for Biotechnology Information (NCBI) nucleotide database. Using the Basic Local Alignment Search Tool (BLAST), in the same database, we searched for eukaryotic homologs of the genetic loci of the above strain. SplitsTree and RDP4 were applied respectively for recombination and phylogenetic analyses. Findings: We could identify the 1176-bp genomic region of the C. tetani strain that shared 99.83 % of the DNA identity with those of several eukaryotic organisms of plant origin (Fig. 1), being associated with 18S ribosomal RNA, or long non-coding RNAs, or hypothetical proteins.
Fig. 1. The Neighbor-joining tree, showing the genetic relationships between the BLAST-identified organisms, and DNA identity statistics for their homologs in respect to the 1176-bp genomic region of the C. tetani strain.
As shown, no respective DNA homology of the above region could be found in the bacterial species genomes, with a very few exceptions represented by a single strain. The splits decomposition analysis could identify genetic recombination events displayed by a single parallelogram (Fit: 100; bootstrap values: 62.7-64.3 for the nodes), being shared by C. tetani and several eukaryotes such as P. pretense, S. bicolor, S. officinarum, P. hallii, and P. pretense. The RDP4 PHI test-generated p value was 0.00001.
Conclusion & Significance: C. tetani appears to have the ability to acquire certain eukaryotic DNA of plant origin. It is highly imperative to determine whether in the above C. tetani strain genome, the 1176-bp genomic region serves as a functional domain associated with its virulence, pathogenicity, and/or environmental persistence.