Comparison of culture, PCR and immunoassays for detecting Escherichia coli O157 following enrichment culture and immunomagnetic separation performed on naturally contaminated raw meat products

In this study, 100 raw meat samples were collected from 15 local Moroccan butcheries in five different areas of the city of Rabat during a period of 4 months. Overall, 7 of 15 butcheries from three areas of the city yielded strains of Escherichia coli O157. Single isolates from 9 (9%) of 100 raw meat samples were biochemically and serologically confirmed as E. coli O157. Using molecular techniques, two strains were positive for the Shiga toxin, with two additional strains containing an attaching-effacing gene. All potentially virulent serotypes isolated from these meat samples showed distinct pulsed-field gel electrophoresis profiles. Based on antibiotic susceptibility testing, more than 70% of the isolates were resistant to ampicillin and clavulanic acid–amoxicillin. Moreover, one strain was resistant to more than three antibiotics. Our study represents the first survey of E. coli O157 and related serotypes in raw meat products in Morocco.

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Occurrence of Escherichia coli O157:H7 in retail raw meat products in Ethiopia

The Journal of Infection in Developing Countries ◽

10.3855/jidc.203 ◽

2008 ◽

Vol 2 (05) ◽

Cited By ~ 4

Author(s):

Daniel Asrat ◽

Adem Hiko ◽

Girma Zewde

Keyword(s):

Escherichia Coli ◽

Meat Products ◽

Escherichia Coli O157 ◽

Raw Meat

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Influence of raw meat natural background flora on growth of Escherichia coli O157: H7 in ground beef

Revista de Microbiologia ◽

10.1590/s0001-37141999000300015 ◽

1999 ◽

Vol 30 (3) ◽

pp. 272-277 ◽

Cited By ~ 2

Author(s):

Susana M.I. Saad ◽

Bernadette D.G.M. Franco

Keyword(s):

Escherichia Coli ◽

Pseudomonas Putida ◽

Room Temperature ◽

Foodborne Pathogen ◽

Meat Products ◽

Ground Beef ◽

Escherichia Coli O157 ◽

Natural Background ◽

Raw Meat ◽

Cultural Methods

Escherichia coli O157:H7 is a foodborne pathogen of increasing importance. It has been involved in several threatening outbreaks, most of them associated with meat products. In this study, the influence of some bacteria from the natural background flora of raw meat over E.coli O157:H7 in ground beef stored under refrigeration and at room temperature was evaluated. Different levels of E.coli O157:H7 (101-102, 103-104 and 106-107 CFU/g), inoculated in ground beef samples, were challenged with strains of non-pathogenic E.coli, Pseudomonas putida or Leuconostoc sp. Growth of the pathogen was monitored using standard cultural methods and an ELISA-type rapid method. Non-pathogenic E.coli, Pseudomonas putida and Leuconostoc sp. did not affect growth of E.coli O157:H7 in ground beef, both under refrigeration and at room temperature. Based on these findings, the low occurrence of E.coli O157:H7 in raw meat may not be attributed to antagonistic effects of bacteria from the natural background flora.

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Isolation and Characterization of Escherichia coli O157:H7 from Retail Meats in Argentina

Journal of Food Protection ◽

10.4315/0362-028x-64.9.1346 ◽

2001 ◽

Vol 64 (9) ◽

pp. 1346-1351 ◽

Cited By ~ 55

Author(s):

ISABEL CHINEN ◽

JOSÉ DANIEL TANARO ◽

ELIZABETH MILIWEBSKY ◽

LILIANA HAYDEÉ LOUND ◽

GERMÁN CHILLEMI ◽

...

Keyword(s):

Escherichia Coli ◽

Enrichment Culture ◽

Culture Method ◽

Immunomagnetic Separation ◽

Phage Typing ◽

Escherichia Coli O157 ◽

Potassium Tellurite ◽

E Coli ◽

Isolation And Characterization ◽

Retail Meats

Between February and May 2000, 279 meat samples were collected from 136 retail stores in Gualeguaychú City, Argentina. Samples were assayed for Escherichia coli O157:H7 by selective enrichment in modified EC broth containing novobiocin, followed by immunomagnetic separation (IMS) and plating onto both sorbitol MacConkey agar supplemented with cefixime and potassium tellurite and a chromogenic medium. Eleven E. coli O157:H7 isolates were detected in 6 (3.8%) of 160 ground beef samples, in 4 (4.8%) of 83 fresh sausages, and in 1 (3.3%) of 30 dry sausages. E. coli O157:H7 was not isolated from five hamburger patties or one barbecue-type fresh sausage assayed. The isolates were tested for virulence-related genes. Ten additional Shiga toxin-producing E. coli (STEC) O157:H7 isolates of food origin, recovered from different locations in Argentina, were included for comparison purposes. All 21 isolates harbored both eae and EHEC-hlyA genes, and 12 (57.1%) encoded stx2/stx2vh-a. The isolates were of phage types 87 (seven strains), 14 (four strains), 4 (three strains), and 26 (one strain). Six strains were nontypable by phage typing. Pulsed-field gel electrophoresis (PFGE) revealed 19 XbaI-PFGE profiles. Fifteen (71%) strains were grouped in four clusters, which shared more than 80% of DNA restriction fragments. The enrichment culture method with IMS was a sensitive procedure to detect E. coli O157:H7 strains in retail meats. Some of the isolates from different stores presented a high clonal relatedness, as determined by XbaI-PFGE and phage typing, and harbored the virulence factors associated with human illness.

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Comparison of Cultures from Rectoanal-Junction Mucosal Swabs and Feces for Detection of Escherichia coli O157 in Dairy Heifers

Applied and Environmental Microbiology ◽

10.1128/aem.72.5.3766-3770.2006 ◽

2006 ◽

Vol 72 (5) ◽

pp. 3766-3770 ◽

Cited By ~ 40

Author(s):

Margaret A. Davis ◽

Daniel H. Rice ◽

Haiqing Sheng ◽

Dale D. Hancock ◽

Thomas E. Besser ◽

...

Keyword(s):

Escherichia Coli ◽

Quantitative Data ◽

Enrichment Culture ◽

Immunomagnetic Separation ◽

Escherichia Coli O157 ◽

Fecal Culture ◽

Chi Square ◽

Dairy Heifers ◽

Chi Square Test

ABSTRACT Fecal culture for Escherichia coli O157:H7 was compared to rectoanal mucosal swab (RAMS) culture in dairy heifers over a 1-year period. RAMS enrichment culture was as sensitive as fecal culture using immunomagnetic separation (IMS) (P = 0.98, as determined by a chi-square test). RAMS culture is less costly than fecal IMS culture and can yield quantitative data.

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A detection method of Escherichia coli O157:H7 based on immunomagnetic separation and aptamers-gold nanoparticle probe quenching Rhodamine B’s fluorescence

Food Science and Biotechnology ◽

10.1007/s10068-021-00947-3 ◽

2021 ◽

Author(s):

Fengnan Lian ◽

Dan Wang ◽

Shuo Yao ◽

Lirui Ge ◽

Yue Wang ◽

...

Keyword(s):

Escherichia Coli ◽

Gold Nanoparticle ◽

Detection Method ◽

Immunomagnetic Separation ◽

Escherichia Coli O157

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Surface and Internalized Escherichia coli O157:H7 on Field-Grown Spinach and Lettuce Treated with Spray-Contaminated Irrigation Water

Journal of Food Protection ◽

10.4315/0362-028x-73.6.1023 ◽

2010 ◽

Vol 73 (6) ◽

pp. 1023-1029 ◽

Cited By ~ 122

Author(s):

MARILYN C. ERICKSON ◽

CATHY C. WEBB ◽

JUAN CARLOS DIAZ-PEREZ ◽

SHARAD C. PHATAK ◽

JOHN J. SILVOY ◽

...

Keyword(s):

Escherichia Coli ◽

Irrigation Water ◽

Enrichment Culture ◽

Field Studies ◽

Plate Count ◽

Escherichia Coli O157 ◽

Adaxial Side ◽

Abaxial Side ◽

E Coli ◽

Contaminated Irrigation Water

Numerous field studies have revealed that irrigation water can contaminate the surface of plants; however, the occurrence of pathogen internalization is unclear. This study was conducted to determine the sites of Escherichia coli O157:H7 contamination and its survival when the bacteria were applied through spray irrigation water to either field-grown spinach or lettuce. To differentiate internalized and surface populations, leaves were treated with a surface disinfectant wash before the tissue was ground for analysis of E. coli O157:H7 by direct plate count or enrichment culture. Irrigation water containing E. coli O157:H7 at 102, 104, or 106 CFU/ml was applied to spinach 48 and 69 days after transplantation of seedlings into fields. E. coli O157:H7 was initially detected after application on the surface of plants dosed at 104 CFU/ml (4 of 20 samples) and both on the surface (17 of 20 samples) and internally (5 of 20 samples) of plants dosed at 106 CFU/ml. Seven days postspraying, all spinach leaves tested negative for surface or internal contamination. In a subsequent study, irrigation water containing E. coli O157:H7 at 108 CFU/ml was sprayed onto either the abaxial (lower) or adaxial (upper) side of leaves of field-grown lettuce under sunny or shaded conditions. E. coli O157:H7 was detectable on the leaf surface 27 days postspraying, but survival was higher on leaves sprayed on the abaxial side than on leaves sprayed on the adaxial side. Internalization of E. coli O157:H7 into lettuce leaves also occurred with greater persistence in leaves sprayed on the abaxial side (up to 14 days) than in leaves sprayed on the adaxial side (2 days).

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