SUTTERELLA WADSWORTHENSIS GEN-NOV, SP-NOV, BILE-RESISTANT MICROAEROPHILIC CAMPYLOBACTER GRACILIS-LIKE CLINICAL ISOLATES

Campylobacter gracilis (formerly Bacteroides gracilis) is an asaccharo lytic, nitrate-positive, urease negative organism that requires format e and fumarate or hydrogen as a growth additive and may pit agar media , Clinical isolates that were obtained primarily from appendiceal and peritoneal fluid specimens and initially were identified in our labora tory as B. gracilis were later found to include ''unusual'' strains th at could be distinguished by biochemical and genetic criteria, These u nusual C.gracilis strains were bile resistant, could not reduce tetraz olium chloride under aerobic conditions if formate and fumarate were a dded to the medium, and could grow in the presence of 2 or 6% oxygen i f no blood was added to the medium, C, gracilis, other campylobacters, and the unusual strains produced distinctive dehydrogenase patterns w hen gels were incubated anaerobically, A cellular fatty acid analysis revealed that the cluster formed by the unusual organisms was distinct from the (separate) clusters formed by C.gracilis, Bacteroides ureoly ticus, and other Campylobacter species, 16S rRNA sequence data indicat ed that these organisms are not related phylogenetically to either C, gracilis or other Campylobacter species; the most closely related taxa as determined by rRNA sequence analysis were unrelated aerobes (membe rs of the genera Bordetella, Alcaligenes, Rhodocyclus, and Comamonas). DNA homology data confirmed that these taxa are separate groups, Our data indicate that the unusual organisms are members of a new genus an d new species, for which we propose the name Sutterella wadsworthensis . The type strain of S. wadsworthensis is strain WAL 9799 (= ATCC 5157 9).