Chromobacterium haemolyticum sp. nov., a strongly haemolytic species

A Gram-negative bacterium, strain MDA0585^T, isolated from a sputum culture, was characterized by a polyphasic approach. The 16S rRNA gene and a conserved portion of the DNA gyrase A gene were sequenced and analysed phylogenetically. Strain MDA0585^T showed the closest relationships with Chromobacterium violaceum ATCC 12472^T and Chromobacterium subtsugae PRAA4-1^T (96.1% and 96.3% 16S rRNA gene sequence similarity, respectively). The cellular fatty acids of strain MDA0585T consisted mainly of C₁6_:0, C_16:1ω7c and C_16:1ω6c (summed feature 3) and C_18:1ω7c and C_18:1ω6c (summed feature 8), a profile that was similar to, but distinguishable from, those of C. violaceum ATCC 12472^T and C. subtsugae PRAA4-1^T. In culture, strain MDA0585^T differed from C. violaceum and C. subtsugae in several ways: lack of violet pigmentation, the ability to haemolyse sheep blood, differences in several biochemical reactions and higher resistance to antibiotics. The culture supernatant of strain MDA0585^T also caused remarkable haemolysis of human erythrocytes. These results suggest that strain MDA0585^T represents a novel species within the genus Chromobacterium, for which the name Chromobacterium haemolyticum sp. nov. is proposed. The type strain is MDA0585^T (=CCUG 53230^T=JCM 14163^T=DSM 19808^T).