Identification and characterization of sporadic isolates of Streptococcus iniae isolated from humans

Seven reference strains and seven clinical isolates of Streptococcus iniae, submitted to the Centers for Disease Control and Prevention Streptococcus Reference Laboratory between 2001 and 2004, were successfully identified by a conventional identification system. The seven randomly submitted clinical isolates were sensitive to beta-lactams, macrolides, quinolones, and vancomycin. Two of the seven clinical isolates were resistant to tetracycline. All seven strains grew well and multiplied in a phagocytosis assay. One of the seven randomly submitted strains was more similar to the type strain of S. iniae than to the other six strains. The latter six strains were similar if not identical to representative strains from a cluster of disease in Canada (M. R. Weinstein et al., N. Engl. J. Med. 337:589-594, 1997).