OCCURRENCE OF ESCHERICHIA-COLI O157 AND OTHER VEROCYTOTOXIN-PRODUCINGESCHERICHIA-COLI IN RETAIL RAW MEATS IN THE NETHERLANDS

Raw meats obtained from retail outlets in the Netherlands were examine d for the presence of Escherichia coli of serogroup O157 and other ver ocytotoxin (VT)-producing E. coli (VTEC), in three different surveys. In the first survey O157 VTEC were detected and isolated by selective plating onto sorbitol MacConkey agar following selective enrichment in modified tryptone soy broth with acriflavin. The organisms were isola ted from 2 (0.3%) of 770 samples of minced mixed beef and pork, but no t detected in samples of raw minced beef (n = 1,000), minced pork (n = 260), or poultry products (n = 300). In the second survey an addition al 360 raw meats were examined with the 3M Petrifilm(TM) Test Kit-HEC, after selective enrichment in modified E. coli broth containing novob iocin. VT-negative E. coli O157 strains were isolated from 22 (6.1%) s amples. In the third survey 180 enrichment cultures of the first surve y were screened for the presence of VT1 and VT2 genes with a polymeras e chain reaction (PCR). Twenty-nine (16.1%) of the 180 enrichment cult ures showed a positive PCR: one for the VT1 gene only, 17 for the VT2 gene only, and 11 for both the VT1 and VT2 gene. A total of 46 VTEC st rains were isolated from 10 randomly selected PCR-positive samples. Se rotyping revealed that 41 of the 46 VTEC isolates belonged to nine dif ferent O serogroups; the remaining five were unidentifiable. A number of the serogroups recovered have been associated with human disease.