Subtyping of stx-genes in Shigatoxin producing Escherichia coli (STEC) - Presence in raw foods and correlation to other factors

Citation
P. Gallien et al., Subtyping of stx-genes in Shigatoxin producing Escherichia coli (STEC) - Presence in raw foods and correlation to other factors, FLEISCHWIRT, 79(6), 1999, pp. 99-103
Citations number
7
Categorie Soggetti
Food Science/Nutrition
Journal title
FLEISCHWIRTSCHAFT
ISSN journal
0015363X → ACNP
Volume
79
Issue
6
Year of publication
1999
Pages
99 - 103
Database
ISI
SICI code
0015-363X(1999)79:6<99:SOSISP>2.0.ZU;2-T
Abstract
We subtyped the six-genes in STEC isolates from foods like raw and certifie d milk, raw minced beef or other undercooked meat samples and raw sausage c ontaining beef. Furthermore correlations to 10 other factors and the serogr oup were investigated. For this study we used 17 STEC (VTEC) isolates from milk, 44 STEC (VTEC) strains from meat samples and STEC (VTEC) isolates fro m samples of raw sausage containing beef. All 68 isolates showed in PCR an amplificate by using the primer pair LP 43/LP 44. The target sequence of th is primer pair is within the A subunit of the stx-subtypes stx 2, stx 2c, s tx 2d and stx 2e. A subtyping was possible by using special primer pairs. 5 6 (82,3 %) of the isolates showed the stx 2 gene, 25 (36,8 %) of the strain s showed the six 2c gene, 7 (10,3 %) of the isolates showed the stx 2d-gene and 9 (13,2 %) of the isolates gave a positive reaction for stx 2e-gene. M any strains had 2 different stx-types and 3 isolates showed the genes stx 1 , stx 2 and stx 2c. We detected the stx 1-gene in 16 (23,5 %) of the isolat es by using the PCR-primers KS 7/ KS 8. We could detect the stx 2e-gene onl y in isolates from samples of raw minced beef or undercooked meat and in sa mples of raw sausage containing beef. The content of other virulence genes in strains containing the stx2d-gene was very low. This fact could gain imp ortance for the differentiation between STEC- and EHEC-strains. Tn addition different sis-genes in STEC could cause different expressions of toxins. A s a consequence the sensitivity of screening tests using the toxin protein as target could vary.