scholarly journals Occurrence of Escherichia coli O157:H7 in river water determined by flow cytometry.

1998 ◽  
Vol 13 (2) ◽  
pp. 77-83 ◽  
Author(s):  
YASUNOBU TANAKA ◽  
MASATO YOSHIMITSU ◽  
NOBUYASU YAMAGUCHI ◽  
KATSUJI TANI ◽  
MASAO NASU
Keyword(s):  
Escherichia Coli ◽  
Flow Cytometry ◽  
River Water ◽  
Escherichia Coli O157

scholarly journals Development and Characterization of a Fluorescent-Bacteriophage Assay for Detection of Escherichia coli O157:H7

1999 ◽  
Vol 65 (4) ◽  
pp. 1397-1404 ◽  
Author(s):  
Lawrence Goodridge ◽  
Jinru Chen ◽  
Mansel Griffiths
Keyword(s):  
Escherichia Coli ◽  
Flow Cytometry ◽  
Immunomagnetic Separation ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Lower Detection ◽  
Unreliable Method ◽  
Direct Epifluorescent Filter Technique ◽  
Bacterial Concentrations

ABSTRACT In this paper we describe evaluation and characterization of a novel assay that combines immunomagnetic separation and a fluorescently stained bacteriophage for detection of Escherichia coliO157:H7 in broth. When it was combined with flow cytometry, the fluorescent-bacteriophage assay (FBA) was capable of detecting 104 cells/ml. A modified direct epifluorescent-filter technique (DEFT) was employed in an attempt to estimate bacterial concentrations. Using regression analysis, we calculated that the lower detection limit was between 102 and 103cells/ml; however, the modified DEFT was found to be an unreliable method for determining bacterial concentrations. The results of this study show that the FBA, when combined with flow cytometry, is a sensitive technique for presumptive detection of E. coliO157:H7 in broth cultures.

scholarly journals Escherichia coli O157 in natural river water.

1999 ◽  
Vol 14 (2) ◽  
pp. 101-105 ◽  
Author(s):  
KATSUJI TANI ◽  
MASAO NASU
Keyword(s):  
Escherichia Coli ◽  
River Water ◽  
Escherichia Coli O157 ◽  
Natural River Water

Immunomagnetic Separation and Flow Cytometry for Rapid Detection of Escherichia coli O157:H7

1998 ◽  
Vol 61 (7) ◽  
pp. 812-816 ◽  
Author(s):  
K. H. SEO ◽  
R. E. BRACKETT ◽  
J. F. FRANK ◽  
S. HILLIARD
Keyword(s):  
Escherichia Coli ◽  
Flow Cytometry ◽  
Magnetic Beads ◽  
Fluorescent Antibody ◽  
Potassium Phosphate ◽  
Immunomagnetic Separation ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Natural Flora ◽  
Short Time

A rapid method for detecting Escherichia coli O157:H7 combining immunomagnetic beads (IMB) and flow cytometry was developed. Labeling antigens separated by IMB with fluorescent antibody enabled the detection of <103 CFU bacteria per ml in pure culture. The optimum concentration of magnetic beads for flow cytometry was lower (ca. 105 particles per ml) than that reported for conventional IMB assay (more than 6 × 106 to 8 × 106 particles per ml). Immunomagnetic separation and flow cytometry (IMFC) were evaluated for detecting E. coli O157:H7 in the presence of a competing microorganism and for detecting antibodies in potassium phosphate buffer. The total assay time from separating antigens with IMB to analyzing with flow cytometry was about 1 h. IMFC detected 103 to 104 CFU of E. coli O157:H7 per ml in ground beef enrichment broth and could effectively discriminate between E. coli O157:H7 and competing natural flora. The new assay system provides another approach to separation and detection of low populations of pathogens and shows potential for detecting low concentrations of toxins and other soluble antigens directly from food in a short time.

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