Genomic Evolution of Siccibacter colletis: Comparative Analysis and First Clinical Isolate Report

Area of Science:

• Microbiology
• Genomics
• Clinical Medicine

Background:

• The genus Siccibacter comprises environmental bacteria, with Siccibacter colletis previously isolated solely from plant-associated environments.
• Clinical infections caused by Siccibacter species have not been previously documented.

Purpose of the Study:

• To characterize the first reported clinical isolate of Siccibacter colletis (strain S25242).
• To investigate the genomic evolution and clinical relevance of this environmental bacterium.
• To understand the transition of Siccibacter colletis from an environmental organism to a potential opportunistic pathogen.

Main Methods:

• Isolation and identification of a clinical bacterial strain from a patient urine sample.
• Whole-genome sequencing and analysis of the S25242 isolate.
• Phylogenetic and phylogenomic analyses to determine taxonomic status.
• Comparative genomics to identify specific and unique genes.

Main Results:

• Strain S25242, isolated from a severe urinary tract infection, was confirmed as Siccibacter colletis based on genomic data (dDDH and ANI values).
• The genome of S25242 contains genes associated with multidrug efflux systems and unique genes related to transposition and DNA integration.
• The isolate demonstrated susceptibility to all tested antimicrobials.

Conclusions:

• This study reports the first clinical isolate of Siccibacter colletis, demonstrating its capacity to cause human infections.
• Genomic plasticity, including the presence of specific and unique genes, likely facilitates Siccibacter colletis's adaptation to a clinical environment.
• Enhanced clinical surveillance of the Siccibacter genus is recommended to monitor potential opportunistic infections.