DNA-PROBE AND POLYMERASE CHAIN-REACTION PROCEDURE FOR THE SPECIFIC DETECTION OF SERPULINA-HYODYSENTERIAE

Serpulina (Treponema) hyodysenteriae, a Cram-negative anaerobic spiroc hete, is the causative agent of swine dysentery, a mucohaemorrhagic di arrheal disease in which lesions are confined to the large intestine o i pigs. A DNA probe and polymerase chain reaction (PCR) amplification procedures which are specific, rapid, and sensitive for the detection of S. hyodysenteriae have been developed. Clone pF12 from a plasmid li brary of S. hyodysenteriae B204 genomic DNA was identified as a clone specific for S. hyodysenteriae but not for S. innocens by differential hybridization screening with S. hyodysenteriae and S, innocens genomi c DNA probes. A DNA probe consisting of a 1.3 kb restriction fragment from pF12 was found to be highly specific for S. hyodysenteriae and de tected 10(5) bacterial cells. A PCR procedure using primers derived fr om this fragment yielded a single product which was specifically gener ated for S. hyodysenteriae template DNA and not for other control cell s DNA. PCR provided increased sensitivity with the direct detection of as few as 10 S. hyodysenteriae cells. The PCR procedure could detect S. hyodysenteriae cells in seeded faecal matter. Moreover, the PCR ass ay was able to detect most S. hyodysenteriae field isolates of serotyp es 8 and 9. These tools have diagnostic application in veterinary micr obiology.