VIRULENCE DETERMINANTS INVA AND SPVC IN SALMONELLAE ISOLATED FROM POULTRY PRODUCTS, WASTE-WATER, AND HUMAN SOURCES

The presence of two virulence foci, invA and spvC, in Salmonella isola tes obtained from poultry, wastewater, and human sources was determine d. All isolates (n = 245) were positive for the invA gene sequence, Di fferences in degree of invasiveness were apparent with the Madin Darby canine kidney cell line, as only 79 of 159 randomly selected isolates (49.7%) tested were invasive at >0.1% of the inoculum, 25% were invas ive between 0.1 and 1.0% of the inoculum, and 24.5% were invasive at > 1.0% of the inoculum. There was a significant correlation between degr ee of invasion and source from which the isolate was recovered but no correlation between geographic origin of poultry isolates and degree o f invasion, Only 37 of 245 isolates (15.1%) hybridized with the spvC D NA probe, All isolates that were recovered from a commercial egg produ ction environment and chicken eggs and whose sequences exhibited homol ogy with the spvC gene sequence were determined to be either Salmonell a enteritidis PT 23 or PT 13. The sequences of few isolates from ceca and none from wastewater or humans demonstrated homology with the spvC gene.