Novel molecular techniques for the identification of the members of Brucellaceae family

Abstract

An account is presented of an attempt to identify a multiresistant, gram-negative bacterium that was isolated from raw sewage in Cyprus. The API 2ONE system was initially used to identify the strain on the basis of its biochemical profile. In addition, a 16S rRNA-specific PCR was applied on genetic material extracted directly from BGM cell culture material after which the sequence of the largest part of the 16S rRNA gene (approximately 1000 nucleotides) was obtained BLAST software was used to compare the sequences obtained with corresponding sequences of other strains belonging to members of the family Brucellaceae, which were available in the GenBank database. The isolated bacterium was identified as Ochrobactrum anthropi by both its biochemical profile and its 16S rRNA sequences, which showed a 98% similarity with other O. anthropi strains. It was found to be resistant to several antibiotics, including b-lactams and aminoglycosides. Phylogenetic analysis showed that 16S rRNA gene sequencing should be used with caution for the identification of family Brucellaceae members that are genetically closely related. In conclusion, this study recorded the first isolation of an O. anthropi strain from environmental samples in Cyprus. This strain was found to be highly resistant to antibiotics. Sequencing of the 16S rRNA gene was useful for the verification of the identity of the strain. However, phylogenetic comparisons with other related bacterial strains showed that this method is perhaps not the most decisive for identification of members of the family Brucellaceae, due to the consonance between different species and genera.