USE OF COMMERCIAL ENZYME KITS AND FATTY-ACID PRODUCTION FOR THE IDENTIFICATION OF SERPULINA-HYODYSENTERIAE - A POTENTIAL MISDIAGNOSIS

The accuracy of identification of Serpulina hyodysenteriae strains gro wn in a complex medium was 90% when 2 commercial test kits were used. Unlike the other S. hyodysenteriae strains, S. hyodysenteriae strain P 35/2 was unusual in being indole negative. The nonpathogenic intestina l spirochete PWS/A, which is from a different species, was indole posi tive and cu-galactosidase negative. Identification of these spirochete s on the basis of these kits alone would have been incorrect. The anal ysis of volatile fatty acids by gas chromatography showed that the rat io of acetic to butyric acid was from 11:1 to 44:1 for S. hyodysenteri ae strains, which distinguished them from the other spirochetes. The e xception was PWS/A (acetic:butyric of 32:1), but this spirochete, unli ke the S. hyodysenteriae spirochetes, also produced isobutyric acid. S hort chain fatty acid (SCFA) analysis by high-performance liquid chrom atography detected different SCFAs in addition to acetic and butyric a cids. These additional SCFAs did not contribute to further differentia tion of the porcine spirochetes.