Detection of Escherichia coli O157:H7 in soil and water using multiplex PCR.
OBJECTIVE
To evaluate the suitability of a multiplex PCR-based assay for sensitive and rapid detection of Escherichia coli O157:H7 in soil and water.


RESULTS
Soil and water samples were spiked with E. coli O157:H7 and subjected to two stages of enrichment prior to multiplex PCR. Detection sensitivities were as high as 1 cfu ml(-1) drinking water and 2 cfu g(-1) soil. Starvation of E. coli O157:H7 for 35 d prior to addition to soil did not affect the ability of the assay to detect initial cell numbers as low as 10 cfu g(-1) soil. Use of an 8-h primary enrichment enabled detection of as few as 6 cfu g(-1) soil, and 10(4) cfu g(-1) soil with a 6-h primary enrichment. When soil was inoculated with 10(5) cfu g(-1), the PCR assay indicated persistence of E. coli O157:H7 during a 35 d incubation. However, when soil was inoculated with lower numbers of pathogen, PCR amplification signals indicated survival to be dependent on cell concentration.


CONCLUSIONS
A multiplex PCR-based assay, in combination with an enrichment strategy enabled sensitive and rapid detection of E. coli O157:H7 in soil and water.


CONCLUSIONS
The ability to sensitively detect E.coli O157:H7 in environmental material within one working day represents a considerable advancement over alternative more time-consuming methods for detection of this pathogen.
Campbell
G R
GR
Department of Plant and Soil Science, University of Aberdeen, Aberdeen, Scotland, UK.
Prosser
J
J
Glover
A
A
Killham
K
K
D004269:DNA, Bacterial / Q000032:analysis; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D012988:Soil Microbiology; D014871:Water Microbiology
D004269:DNA, Bacterial