Phenotypic and Genotypic Comparisons among Strains of the Lobster Pathogen Aerococcus viridans and Other Marine Aerococcus viridans-Like Cocci

The lobster pathogen Aerococcus viridans and other gram-positive, marine A. viridans-like cocci were examined morphologically, biochemically, and genetically. Morphologically, the lobster pathogenic strains were unique in their tetrad-forming capacity. Because of intragroup fermentative variations among the lobster-pathogenic strains and values of deoxyribonucleic acid (DNA) base composition overlapping those of the other cocci, the lobster pathogens did not stand out as a separate group based on these data. According to the DNA-DNA hybridization studies, however, the lobster-pathogenic strains were very closely related (80 to 100% homology) and could be easily separated from the remaining strains. All the cocci had extraordinarily small genomes ranging from 0.57 x 109 to 1.01 x 109 daltons.