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Abstract
In this study we examined the taxonomic relationships of strains variously labeled Achromobacter species biotypes 1 and 2, Achromobacter group A, and Centers for Disease Control (CDC) groups Vd-1 and Vd-2. Previous studies of ribosomal ribonucleic acid cistron similarities placed these organisms on the Brucella ribosomal ribonucleic acid branch of ribosomal ribonucleic acid superfamily IV; their closest neighbors were Brucella, Phyllobacterium, and the Agrobacterium-Rhizobium complex. We performed a numerical taxonomic analysis of 284 phenotypic features (69 conventional tests, 147 API assimilation tests, 68 API ZYM tests) carried out on 95 strains. These organisms comprised 56 strains thought to correspond to CDC group Vd (including 3 strains originally labeled “Pseudomonas arsenoxydans”) and 39 strains (included for reference purposes) representing the genera Achromobacter, Agrobacterium, Alcaligenes, Brucella, Mycoplana, Phyllobacterium, and Rhizobium. A phenotypic analysis showed that group Vd bacteria are most similar to Phyllobacterium. However, strains of Group Vd were shown to be distinct by deoxyribonucleic acid (DNA)-DNA hybridization and by several phenotypic tests from Phyllobacterium and other related taxa. The CDC group Vd strains formed essentially a single taxon in the numerical taxonomic analysis of phenotypic characters and as determined by DNA-DNA hybridization. This taxon could be subdivided into three biotypes (biotypes A, C, and D), but none of these corresponded to the two biotypes originally described among the group Vd strains. For CDC group Vd we propose a new genus and new species, Ochrobactrum anthropi: The type strain is strain CIP 82.115 (= CIP 14970 = NCTC 12168 = LMG 3331). O. anthropi strains are rod shaped, aerobic, gram negative, nonpigmented, and motile by means of peritrichous flagella, produce acid from several carbohydrates, and reduce both nitrate and nitrite. The guanine-plus-cytosine contents of the DNAs of 29 strains ranged from 56 to 59 mol%. Almost all 56 group Vd strains were originally isolated from various human clinical specimens, commonly from blood cultures.
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