Comparison of three methods for identification of clinical isolates of Aeromonas

Objective To compare the identification effects of clinical isolates ofAeromonas by using multi locus phylogenetic analysis (MLPA), mass spectrometer (VITEK MS system) and biochemical analyzer (VITEK Ⅱ system) and provide evidence for the research of species identification and classification of Aeromonas.

Methods The Aeromonas strains isolated from clinical specimens of hospitalized patients and outpatients suffered from diarrhea in our hospital between December 2014 and October 2017 were collected for the identification with VITEK MS system, VITEK Ⅱ system and MLPA, respectively.

Results The isolated Aeromonas strains were divided into 10 species by MLPA, i.e. A. veronii, A. caviae, A. hydrophila, A. dhakensis, A. enteropelogenes, A. media, A. sanarellii, A. taiwanensis, A. bivalvium, and A. allosaccharophila. The identification rate of Aeromonas was 100.0% at genus level and 16.2% at species level by VITEK MS system, in addition, the identification rate was 83.3% (5/6) for A. enteropelogenes and 50.0% (1/2) for A. media. The identification rate of Aeromonaswas 89.2% at genus level and 0 (unspecified and false) at species level by VITEK Ⅱ system.

Conclusion MLPA was an accurate tool for the delineation of Aeromonas species. VITEK MS system was more accurate than VITEK Ⅱ system to identify Aeromonasat both the genus and species level. VITEK MS system had a certain ability to identify rare species of A. enteropelogenesand A. media.