Citrobacter meridianamericanus sp. nov., isolated from a soil sample

A Gram- stain-negative strain, designated BR102T, isolated from a soil sample in Brazil was characterized by a polyphasic approach. Comparative 16S rRNA gene sequences indicated that strain BR102T belonged to the genus Citrobacter. The recN- and whole-genome- based phylogeny, and multilocus sequence analysis based on concatenated partial fusA, leuS, pyrG and rpoB sequences strongly supported a clade encompassing strain BR102T and a strain from public database that was distinct from currently recognized species of the genus Citrobacter. Average nucleotide identity and digital DNA-DNA hybridization values between strain BR102T and the closest relative Citrobacter freundii ATCC 8090T were 91.8 and 48.8 %, respectively. The ability to metabolize different compounds further discriminated strain BR102T from other closely related species of the genus Citrobacter. The novel variants blaCMY-179 and qnrB97, which encoded a CMY- 2- like & beta;-lactamase and a QnrB- type protein, respec-tively, were identified in strain BR102T. BR102T was resistant to ampicillin, amoxicillin/clavulanate and cefoxitin. The DNA G+C content of strain BR102T is 51.3 mol%. Based on these results, strain BR102T represents a novel species of the genus Citrobacter, for which the name Citrobacter meridianamericanus sp. nov. is proposed. The type strain is BR102T (=MUM 22.55T=IMI 507229T).

Automated summary

A Gram-stain-negative strain BR102T isolated from a soil sample in Brazil was identified as a novel species of the genus Citrobacter, named Citrobacter meridianamericanus sp. nov. Strain BR102T showed distinct genetic sequences from recognized species in the genus Citrobacter. It also exhibited unique abilities to metabolize compounds and carried novel variants of blaCMY-179 and qnrB97 genes. The findings suggest the significance of strain BR102T in expanding our understanding of the diversity of the genus Citrobacter.