Identification of two distinct hybridization groups in the genus Hafnia by 16S rRNA gene sequencing and phenotypic methods.

A collection of 52 strains belonging to the Hafnia alvei complex were subjected to molecular (16S rRNA gene sequencing) and biochemical analysis. Based upon 16S rRNA gene sequencing results, two genetic groups were identified which correspond with previously recognized DNA hybridization group 1 (ATCC 13337(T) and ATCC 29926; n = 23) and DNA hybridization group 2 (ATCC 29927; n = 29). Of 46 biochemical tests used to characterize hafniae, 19 reactions (41%) yielded variable results. Of these 19 tests, 6 were determined to have discriminatory value in the separation of DNA groups 1 and 2, with malonate utilization found to be the most differential test. Test results of malonate utilization alone correctly assigned 90% of Hafnia isolates to their correct DNA group.