Isolation of potentially novel Brucella spp. from frogs

Abstract

Bacterial isolates from frogs were phenotypically identified as Ochrobactrum anthropi, but 16S rRNA sequencing showed up to 100% identity with Brucella inopinata. Further analysis of recA, omp2a, omp2b, bcsp31, and IS711 and multilocus sequence analysis (MLSA) verified a close relationship with Brucella, suggesting the isolates may actually represent novel members of this growing genus of zoonotic pathogens.

Fig 1

Relationships of two bullfrog isolates (09RB8471 and 10RB9215) with Brucella and Ochrobactrum isolates based on eight-locus MLSA. Sequences were concatenated, and the phylogenetic tree was constructed by the neighbor-joining approach. For ease of presentation, the Brucella clade is reduced in panel A to show relationships with the Ochrobactrum, and the subtree is presented separately in panel B to show the relationships among the Brucella complex in more detail. Numbers at nodes correspond to proportions of 100 resamplings that support the topology shown, with only values of >70% indicated. The bar indicates the number of substitutions per nucleotide position.