Phenotypic and genotypic characteristics of Arcanobacterium haemolyticum isolated from clinical samples in a Danish hospital.

Six Arcanobacterium haemolyticum strains isolated from six patients of two hospitals in Denmark were identified phenotypically, also including matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis, and by genotypic methods. The latter were performed by sequencing 16S rDNA and glyceraldehyde 3-phosphate dehydrogenase encoding gene gap and by amplification of an A. haemolyticum specific region of 16S-23S rDNA intergenic spacer region and 23S rDNA. The six A. haemolyticum strains were further investigated for the presence of seven potential virulence genes encoding arcanolysin, phospholipase D, hemolysin A, CAMP factor family protein, collagen binding protein, neuraminidase A and neuraminidase H which appeared to be present in two (seven virulence genes), two (six virulence genes) and two strains (four virulence genes), respectively. The phenotypic and genotypic properties described in the present study might help to reliably identify and further characterize A. haemolyticum isolated from human patients, a species which seems to be of increasing importance.