Dead-end ultrafiltration concentration and IMS/ATP-bioluminescence detection of Escherichia coli O157:H7 in recreational water and produce wash

An automated concentration system (ACS) based on dead-end ultrafiltration was used in this study to concentrate bacteria, including Escherichia coli O157:H7, from 50-liter produce washes (PWs, sieved produce wash). Cells trapped in the filters were recovered in approximately 400 ml of buffer to create PW retentates (PWRs). Extent of concentration was determined by analyzing PWs and PWRs for total coliform bacteria and E. coli O157:H7 using standard methods. In addition, an electrochemiluminescence immunoassay was evaluated for detection of E. coli O157:H7 in spiked PWs and PWRs to demonstrate usefulness of the ACS for same-day detection. The levels of total coliform bacteria and E. coli O157:H7 in PWRs were higher than those in PWs by 1.85± 0.41 log most probable number per 100 ml and 1.82 ± 0.24 log CFU/ml, respectively. Electrochemiluminescence detection of E. coli O157:H7 was accomplished within 2 h using ACS concentration of lettuce and spinach wash water artificially spiked with the pathogen at levels as low as 0.36 log CFU/ml and 1.39 log CFU/ml, respectively. Detection of E. coli O157:H7 at −0.93 ± 0.15 log CFU/ml in lettuce wash occurred within approximately 6 h when a 4-h enrichment step was added to the procedure. Use of dead-end ultrafiltration increased bacterial concentrations in PWR and allowed same-day detection of low levels of E. coli O157:H7 in PW. This concentration system could be useful to improve the sensitivity of current rapid methods for detection of low levels of foodborne pathogens in PW water.

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Laboratory and Pilot-Scale Dead-End Ultrafiltration Concentration of Sanitizer-Free and Chlorinated Lettuce Wash Water for Improved Detection of Escherichia coli O157:H7

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-421 ◽

2014 ◽

Vol 77 (8) ◽

pp. 1260-1268 ◽

Cited By ~ 9

Author(s):

SONIA MAGAÑA ◽

SARAH M. SCHLEMMER ◽

GORDON R. DAVIDSON ◽

ELLIOT T. RYSER ◽

DANIEL V. LIM

Keyword(s):

Escherichia Coli ◽

Pilot Scale ◽

Wash Water ◽

Detection Methods ◽

Escherichia Coli O157 ◽

Scale Production ◽

E Coli ◽

Concentration Method ◽

Dead End ◽

Electrochemiluminescence Immunoassay

An automated dead-end (single pass, no recirculation) ultrafiltration device, the Portable Multi-use Automated Concentration System (PMACS), was evaluated as a means to concentrate Escherichia coli O157:H7 from 40 liters of simulated commercial lettuce wash water. The assessment included generating, sieving, and concentrating sanitizer-free lettuce wash water, either uninoculated or inoculated with green fluorescent protein–transformed E. coli O157:H7 at a high (1.00 log CFU/ml) or low (−1.00 log CFU/ml) concentration. Cells collected within the filters were recovered in approximately 400 ml of buffer to create lettuce wash retentates. The extent of concentration was determined by viable plate counts using a medium selective for the transformed E. coli O157:H7. The samples were qualitatively analyzed for E. coli O157:H7 according to the U.S. Food and Drug Administration Bacteriological Analytical Manual enrichment method and with an electrochemiluminescence immunoassay. This concentration method was then evaluated in a pilot-scale production line at Michigan State University using chlorinated (100, 30, and 10 ppm of available chlorine) lettuce wash water. The total PMACS processing times were 82 ±6 and 65 ±5 min for sanitizer-free and chlorinated washes, respectively. Overall, E. coli O157:H7 populations were approximately 2 log higher in retentates than in unconcentrated lettuce wash samples. The higher E. coli O157:H7 levels in the retentates enabled cultural and electrochemiluminescence immunoassay detection in some samples when the corresponding lettuce wash samples were negative. When combined with standard and rapid detection methods, the PMACS concentration method may provide a means to enhance pathogen monitoring of produce wash water.

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Bedeutung von Escherichia coli O157 beim Schlachtschaf in der Schweiz

Schweizer Archiv für Tierheilkunde ◽

10.1024/0036-7281.148.6.289 ◽

2006 ◽

Vol 148 (6) ◽

pp. 289-295 ◽

Cited By ~ 8

Author(s):

C. Zweifel ◽

M. Kaufmann ◽

J. Blanco ◽

R. Stephan

Keyword(s):

Escherichia Coli ◽

Escherichia Coli O157

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Molecular profiling and antimicrobial susceptibility of Escherichia coli O157:H7 isolated in Bulgaria

BULGARIAN JOURNAL OF VETERINARY MEDICINE ◽

10.15547/bjvm.2263 ◽

2020 ◽

Vol 23 (3) ◽

pp. 310-318

Author(s):

K. Koev ◽

T. Stoyanchev ◽

G. Zhelev ◽

P. Marutsov ◽

K. Gospodinova ◽

...

Keyword(s):

Escherichia Coli ◽

Escherichia Coli O157 ◽

Acid Sensitivity ◽

Lower Extent ◽

Phenotype Analysis ◽

Anal Swab ◽

Amoxicillin Clavulanic Acid ◽

Primary Identification ◽

Stx1 Gene ◽

Cattle Farms

The purpose of this study was to detect the presence of shiga-toxin producing Escherichia coli (STEC) in faeces of healthy dairy cattle and to determine the sensitivity of isolates to several antimicrobial drugs. A total of 1,104 anal swab samples originating from 28 cattle farms were examined. After the primary identification, 30 strains were found to belong to serogroup О157. By means of conventional multiplex PCR, isolates were screened for presence of resistance genes stx1, stx2 and eaeА. Twenty-nine strains possesses amplicons with a size corresponding to genes stx2 and eaeA, one had amplicons also for the stx1 gene and one lacked amplicons of all three genes. Twenty-eight strains demonstrated amplicons equivalent to gene H7. The results from phenotype analysis of resistance showed preserved sensitivity to ceftriaxone, ceftazidime, cefotaxime, cephalothin, streptomycin, gentamicin, tetracycline, enrofloxacin and combinations sulfamethoxazole/trimethoprim and amoxicillin/clavulanic acid. Sensitivity to ampicillin was relatively preserved, although at a lower extent.

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