scholarly journals Prevalence and molecular characterisation of shiga-toxin-producing Escherichia coli in raw milk cheeses from Lazio region, Italy

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Selene Marozzi ◽  
Paola De Santis ◽  
Sarah Lovari ◽  
Roberto Condoleo ◽  
Stefano Bilei ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Raw Milk ◽  
Foodborne Diseases ◽  
Control Plan ◽  
Lazio Region ◽  
Standard Methods ◽  
E Coli ◽  
Regional Control ◽  
Unpasteurized Milk

In recent years, the incidence of foodborne diseases caused by shiga toxin-producing <em>Escherichia coli</em> (STEC) has increased globally. For this reason, within the specific regional control plan for the detection of STEC in food products in Italy, the presence of STEC in unpasteurized milk cheeses was investigated. In total 203 samples obtained from March 2011 to December 2013 were analysed, with two standard methods (ISO 16654:2001 and ISO 13136:2012). Two strains of <em>E. coli</em> O157 were isolated (2/161, 1.2%) but did not carry any virulence-associated genes and 22 <em>stx</em>-positive samples (22/146, 15.1%) were detected in enrichment cultures, mostly from ovine cheeses. Only two strains isolated from different ovine cheeses carried <em>stx</em> gene and none of these was <em>eae</em>-positive. This study confirms the presence of <em>stx</em>-positive <em>E. coli</em> and suggests that this type of food cannot be excluded as a potential vehicle of STEC.

Comparison of a New Enrichment Procedure for Shiga Toxin–Producing Escherichia coli with Five Standard Methods

2005 ◽  
Vol 68 (8) ◽  
pp. 1593-1599 ◽  
Author(s):  
MICHAEL A. GRANT
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Shiga Toxin ◽  
Real Time Pcr ◽  
Target Cells ◽  
Macconkey Agar ◽  
Standard Methods ◽  
E Coli ◽  
Canadian Health ◽  
Health Products

A new procedure for enrichment of Escherichia coli O157:H7 and other Shiga toxin–producing E. coli was compared to five standard methods: the British Public Health Laboratory Service, International Standard Method, U.S. Department of Agriculture, Canadian Health Products and Food Branch, and U.S. Food and Drug Administration. The new procedure was comparable to the standard methods in its ability to detect target cells inoculated into foods at approximately 1 CFU g−1. Comparisons were also made of the ability of the six enrichment procedures to detect E. coli O157:H7 against a large background of competitor microorganisms. In these experiments the new procedure yielded more target cells than the other five enrichments by two to three orders of magnitude as determined by enumeration on sorbitol MacConkey agar with tellurite and cefixime and Rainbow agar with tellurite and novobiocin and by verification of presumptive colonies by real-time PCR. For example, the population of enterohemorrhagic E. coli strain 6341 recovered on sorbitol MacConkey agar with tellurite and cefixime after enrichment with the experimental method was 2.42 × 108 CFU ml−1 and 1.80 × 106 CFU ml−1 after enrichment with the Canadian Health Products and Food Branch method, the second most effective in this experiment. In addition, broth cultures resulting from each of the six enrichment procedures were used to prepare templates for real-time PCR detection of stx1/stx2. Resulting threshold cycle (Ct) values after the experimental enrichment were similar to positive control values, whereas the five standard methods produced delayed Ct values or were not detected.

Behavior of Escherichia coli O157:H7 during the Manufacture and Aging of Gouda and Stirred-Curd Cheddar Cheeses Manufactured from Raw Milk

2010 ◽  
Vol 73 (12) ◽  
pp. 2217-2224 ◽  
Author(s):  
DENNIS J. D'AMICO ◽  
MARC J. DRUART ◽  
CATHERINE W. DONNELLY
Keyword(s):  
Escherichia Coli ◽  
Population Level ◽  
Raw Milk ◽  
Escherichia Coli O157 ◽  
Milk Whey ◽  
Selective Enrichment ◽  
Point Counts ◽  
E Coli ◽  
Unpasteurized Milk ◽  
Low Levels

This study was conducted to examine the fate of Escherichia coli O157:H7 during the manufacture and aging of Gouda and stirred-curd Cheddar cheeses made from raw milk. Cheeses were manufactured from unpasteurized milk experimentally contaminated with one of three strains of E. coli O157:H7 at an approximate population level of 20 CFU/ml. Samples of milk, whey, curd, and cheese were collected for enumeration of bacteria throughout the manufacturing and aging process. Overall, bacterial counts in both cheese types increased almost 10-fold from initial inoculation levels in milk to approximately 145 CFU/g found in cheeses on day 1. From this point, counts dropped significantly over 60 days to mean levels of 25 and 5 CFU/g in Cheddar and Gouda, respectively. Levels of E. coli O157:H7 fell and stayed below 5 CFU/g after an average of 94 and 108 days in Gouda and Cheddar, respectively, yet remained detectable after selective enrichment for more than 270 days in both cheese types. Changes in pathogen levels observed throughout manufacture and aging did not significantly differ by cheese type. In agreement with results of previous studies, our results suggest that the 60-day aging requirement alone is insufficient to completely eliminate levels of viable E. coli O157:H7 in Gouda or stirred-curd Cheddar cheese manufactured from raw milk contaminated with low levels of this pathogen.

scholarly journals Escherichia coli O121 outbreak associated with raw milk Gouda-like cheese in British Columbia, Canada, 2018

2021 ◽  
Vol 47 (1) ◽  
pp. 11-16
Author(s):  
Eva Boyd ◽  
Aljosa Trmcic ◽  
Marsha Taylor ◽  
Sion Shyng ◽  
Paul Hasselback ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
British Columbia ◽  
Shiga Toxin ◽  
Raw Milk ◽  
Control Measures ◽  
No Production ◽  
Consumer Awareness ◽  
E Coli ◽  
Epidemiologic Surveillance ◽  
Dairy Plant

Background: In 2018, a Shiga toxin–producing Escherichia coli O121 outbreak that affected seven individuals was associated with raw milk Gouda-like cheese produced in British Columbia, Canada. Objectives: To describe the E. coli O121 outbreak investigation and recommend greater control measures for raw milk Gouda-like cheese. Methods: Cases of E. coli O121 were identified through laboratory testing results and epidemiologic surveillance data. The cases were interviewed on exposures of interest, which were analyzed against Foodbook Report values for British Columbia. Environmental inspection of the dairy plant and the cheese products was conducted to ascertain a source of contamination. Whole genome multi-locus sequence typing (wgMLST) was performed on all positive E. coli O121 clinical and food isolates at the provincial laboratory. Results: Four out of the seven cases consumed the same raw milk Gouda-like cheese between August and October 2018. The implicated cheese was aged longer than the required minimum of 60 days, and no production deficiencies were noted. One sample of the implicated cheese tested positive for E. coli O121. The seven clinical isolates and one cheese isolate matched by wgMLST within 6.5 alleles. Conclusion: Raw milk Gouda and Gouda-like cheese has been implicated in three previous Shiga toxin–producing E. coli outbreaks in North America. It was recommended product labelling to increase consumer awareness and thermization of milk to decrease the risk of illness associated with raw milk Gouda and Gouda-like cheese.

scholarly journals Presence of Escherichia coli O157 and O157:H7 in raw milk and Van herby cheese

2015 ◽  
Vol 59 (4) ◽  
pp. 511-514 ◽  
Author(s):  
Yakup Can Sancak ◽  
Hakan Sancak ◽  
Ozgur Isleyici
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Drug Administration ◽  
Shiga Toxin ◽  
Raw Milk ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
Emerging Pathogens ◽  
E Coli ◽  
Milk Samples

Abstract The Shiga toxin-producing Escherichia coli (STEC) strains are currently considered important emerging pathogens threatening public health. Among Shiga toxin-producing Escherichia coli, E. coli O157:H7 strains have emerged as important human pathogens. This study was conducted to determine the presence of Escherichia coli O157 and O157:H7 in raw milk samples and Van herby cheese samples. For this purpose, 100 samples of raw milk were collected and 100 samples of herby cheese sold for consumption in Van province in Turkey were obtained from grocers and markets in order to detect the presence of Escherichia coli O157 and O157:H7. The method of E. coli O157 and O157:H7 isolation proposed by the Food and Drug Administration (FDA) was used. E. coli O157 in raw milk and herby cheese samples was found in 11% and 6% of samples respectively, and E. coli O157:H7 was found in 2% of herby cheese samples. No E. coli O157:H7 was detected in raw milk samples. This study showed that raw milk was contaminated with E. coli O157 and herby cheese was contaminated with both E. coli O157 and E. coli O157:H7; therefore, herby cheese poses a serious risk to public health.

Presence of Multidrug-Resistant Shiga Toxin–Producing Escherichia coli, Enteropathogenic Escherichia coli, and Enterotoxigenic Escherichia coli on Fresh Cheeses from Local Retail Markets in Mexico

2018 ◽  
Vol 81 (11) ◽  
pp. 1748-1754 ◽  
Author(s):  
MARÍA C. de la ROSA-HERNÁNDEZ ◽  
ARTURO CADENA-RAMÍREZ ◽  
ALEJANDRO TÉLLEZ-JURADO ◽  
CARLOS A. GÓMEZ-ALDAPA ◽  
ESMERALDA RANGEL-VARGAS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Pathogenic Bacteria ◽  
Multidrug Resistant ◽  
Enterotoxigenic Escherichia Coli ◽  
Health Concern ◽  
Public Markets ◽  
E Coli ◽  
Unpasteurized Milk ◽  
Fresh Cheese

ABSTRACT Cheesemaking is one of the most important industries in Mexico. Among all the Mexican cheeses, fresh cheeses are the most popular and most consumed cheese in Mexico and Latin America. However, in Mexico fresh cheese is frequently made with unpasteurized milk and sold in public markets. This may increase the risk for contamination of dairy products with pathogenic bacteria. The presence of multidrug-resistant pathogenic bacteria in food is an important public health concern. Diarrheagenic Escherichia coli pathotypes (DEPs) are foodborne bacteria. This study investigated the presence of indicator bacteria and multidrug-resistant DEPs in fresh cheeses. A total of 120 fresh cheese samples were collected from public markets in the city of Pachuca, Mexico. The samples were analyzed for presence of fecal coliforms (FC), E. coli, and antibiotic resistant DEPs. FC and E. coli were analyzed using the most-probable-number technique. DEPs were identified using two multiplex PCR methods. Susceptibility to 16 antibiotics was tested for the isolated DEPs strains by the standard assay. The frequency of FC, E. coli, and DEPs in the cheese samples was 50, 40, and 19%, respectively. The identified DEPs included Shiga toxin–producing E. coli (STEC; 8%), enteropathogenic E. coli (EPEC; 6%), and enterotoxigenic E. coli (ETEC; 5%). All isolated strains exhibited resistance to at least five antibiotics. One, one, two, and three STEC strains were resistant to 14, 12, 11, and 10 antibiotics, respectively. One strain of EPEC was resistant to 11 antibiotics, three EPEC strains to 9, and one strain to 7. One, one, and two strains of ETEC were resistant to 10, 8, and 7 antibiotics, respectively. The results of the present study indicate that fresh cheeses made with unpasteurized milk could be a risk for consumers, both for native people and visitors to Mexico.

scholarly journals Epidemiological Investigation, Serotypes and Distribution of Verocytotoxigenic Escherichia coli (VTEC) in Raw Milk and Milk Products in Uyo, Nigeria

2020 ◽  
Vol 37 (1) ◽  
pp. 10-20
Author(s):  
O.J. Akinjogunla ◽  
B.C. Akaka ◽  
C.U. Inyang
Keyword(s):  
Escherichia Coli ◽  
Cold Water ◽  
Raw Milk ◽  
Epidemiological Investigation ◽  
Milk Products ◽  
E Coli ◽  
Percentage Occurrence ◽  
Unpasteurized Milk ◽  
Food Borne ◽  
Structured Questionnaire

Food borne diseases are of great concern globally especially in the developing countries where poor sanitation is applied during collection and processing of milk from animals. The epidemiological investigation, serotypes and distribution of verocytotoxin (VTI and VT2)- producing Escherichia coli in raw milk and milk products were determined using structured questionnaire, Cefixime tellurite-sorbitol MacConkey agar, agglutination kits and VTEC-RPLA Toxin detection Kit. Out of 27 milkers, 7.4 % had primary education, 22.2 % washed the milk utensils with cold water and soap, 11.1 % washed their hands before milking, while 7.4 % milkers washed the udder of the animals before milking. All the yoghurts had the product names; 85.7 % had NAFDAC numbers; 80.0% had Batch Numbers, while 71.4 % had Manufacturer s’ Addresses. The unpasteurized milk samples had E. coli 0157 and non 0157 E. coli counts (CFU.ml-1) ranging from 4.0 x 102 to 1.7 x 103 and 6.0 x 102 to 2.0 x 103 , respectively, while E. coli 0157 and non 0157 E. coli counts of milk products were between 1.0 x 102 and 1.0 x 103 CFU.ml-1. E. coli 0157 had the highest percentage occurrence (38.3%), while E. coli 0145 had the lowest percentage occurrence (2.1%). More than 38.3% of the E. coli serotypes produced VT2, while ≥ 12.8% were VT1 producers. The occurrence of VTEC in the unpasteurized milk shows that the milkers should be enlightened on the necessary sanitary practices to adopt during milking and also post-pasteurization contamination of milk products should be avoided. Key Words: Verotoxigenic, Escherichia coli, Milk, Yoghurt, Nono, Serotypes.

scholarly journals Detection of Hemolysin Variants of Shiga Toxin-Producing Escherichia coli by PCR and Culture on VancomycinCefixime-Cefsulodin Blood Agar

1998 ◽  
Vol 64 (7) ◽  
pp. 2449-2453 ◽  
Author(s):  
Anselm Lehmacher ◽  
Heidi Meier ◽  
Stojanka Aleksic ◽  
Jochen Bockemühl
Keyword(s):  
Escherichia Coli ◽  
Nucleotide Sequence ◽  
Shiga Toxin ◽  
Raw Milk ◽  
Food Samples ◽  
Blood Agar ◽  
Simple Method ◽  
E Coli ◽  
Alpha Hemolysin ◽  
Pcr Products

ABSTRACT The presence of a hemolysin-encoding gene, elyA orhlyA, from Shiga toxin-producing Escherichia coli (STEC) was detected by PCR in each of 95 strains tested. PCR products of elyA from human STEC isolates of serovars frequently detected in Germany, such as O157:H−, O103:H2, O103:H−, O26:H11, and O26:H−, showed nucleotide sequences identical to previously reported ones for O157:H7 and O111:H− strains. Compared to them, four elyA amplicons derived from human isolates of rare STEC serovars showed identity of about 98% but lacked anAluI restriction site. However, the nucleotide sequence of an amplicon derived from a porcine O138:K81:H− STEC strain was identical to the corresponding region of hlyA, encoding alpha-hemolysin, from E. coli. This hlyAamplicon showed 68% identity with the nucleotide sequence of the corresponding elyA fragment. It differed from theelyA PCR product in restriction fragments generated byAluI, EcoRI, and MluI. Of the 95 representative STEC strains, 88 produced hemolysin on blood agar supplemented with vancomycin (30 mg/liter), cefixime (20 μg/liter), and cefsulodin (3 mg/liter) (BVCC). The lowest added numbers of two to six STEC CFU per g of stool or per ml of raw milk were detectable on BVCC plates after seeding of the preenrichment broth, modified tryptic soy broth (mTSB) supplemented with novobiocin (10 mg/liter), with 16 STEC strains. These strains represented the seven prevailing serovars diagnosed from German patients. However, with ground-beef samples, PCR was essential to identify the lowest added numbers of two to six STEC CFU among colonies of hemolyzing Enterobacteriaceae, such as Serratia spp. and alpha-hemolysin-producing E. coli. We conclude that preenrichment of stool and food samples in mTSB for 6 h followed by overnight culturing on BVCC is a simple method for the isolation and presumptive identification of STEC.

scholarly journals Novel Hybrid of Typical Enteropathogenic Escherichia coli and Shiga-Toxin-Producing E. coli (tEPEC/STEC) Emerging From Pet Birds

2018 ◽  
Vol 9 ◽  
Author(s):  
Rosely Martins Gioia-Di Chiacchio ◽  
Marcos Paulo Vieira Cunha ◽  
Lilian Rose Marques de Sá ◽  
Yamê Minieiro Davies ◽  
Camila Bueno Pacheco Pereira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Enteropathogenic Escherichia Coli ◽  
E Coli ◽  
Pet Birds

Characteristics of Shiga Toxin–Producing Escherichia coli Isolated from Swiss Raw Milk Cheese within a 3-Year Monitoring Program

2010 ◽  
Vol 73 (1) ◽  
pp. 88-91 ◽  
Author(s):  
C. ZWEIFEL ◽  
N. GIEZENDANNER ◽  
S. CORTI ◽  
G. KRAUSE ◽  
L. BEUTIN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Monitoring Program ◽  
Raw Milk ◽  
Health Impact ◽  
Toxin Gene ◽  
Genes Encoding ◽  
Raw Milk Cheese ◽  
Human Infections ◽  
Hard Cheese

Food is an important vehicle for transmission of Shiga toxin–producing Escherichia coli (STEC). To assess the potential public health impact of STEC in Swiss raw milk cheese produced from cow's, goat's, and ewe's milk, 1,422 samples from semihard or hard cheese and 80 samples from soft cheese were examined for STEC, and isolated strains were further characterized. By PCR, STEC was detected after enrichment in 5.7% of the 1,502 raw milk cheese samples collected at the producer level. STEC-positive samples comprised 76 semihard, 8 soft, and 1 hard cheese. By colony hybridization, 29 STEC strains were isolated from 24 semihard and 5 soft cheeses. Thirteen of the 24 strains typeable with O antisera belonged to the serogroups O2, O22, and O91. More than half (58.6%) of the 29 strains belonged to O:H serotypes previously isolated from humans, and STEC O22:H8, O91:H10, O91:H21, and O174:H21 have also been identified as agents of hemolytic uremic syndrome. Typing of Shiga toxin genes showed that stx1 was only found in 2 strains, whereas 27 strains carried genes encoding for the Stx2 group, mainly stx2 and stx2vh-a/b. Production of Stx2 and Stx2vh-a/b subtypes might be an indicator for a severe outcome in patients. Nine strains harbored hlyA (enterohemorrhagic E. coli hemolysin), whereas none tested positive for eae (intimin). Consequently, semihard and hard raw milk cheese may be a potential source of STEC, and a notable proportion of the isolated non-O157 STEC strains belonged to serotypes or harbored Shiga toxin gene variants associated with human infections.

scholarly journals Occurrence of toxigenic Escherichia coli in raw milk cheese in Brazil

2007 ◽  
Vol 59 (2) ◽  
pp. 508-512 ◽  
Author(s):  
B.R. Paneto ◽  
R.P. Schocken-Iturrino ◽  
C. Macedo ◽  
E. Santo ◽  
J.M. Marin
Keyword(s):  
Escherichia Coli ◽  
Polymerase Chain Reaction ◽  
Antimicrobial Agents ◽  
Raw Milk ◽  
Diffusion Method ◽  
Chain Reaction ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Polymerase Chain ◽  
Raw Milk Cheese

The occurrence of toxigenic Escherichia coli in raw milk cheese was surveyed in Middle Western Brazil. Fifty samples of cheese from different supermarkets were analyzed for E.coli. The isolates were serotyped and screened for the presence of verotoxigenic E. coli (VTEC) and enterotoxigenic E. coli (ETEC) by Polymerase Chain Reaction (PCR). The susceptibility to thirteen antimicrobial agents was evaluated by the disk diffusion method. E.coli were recovered from 48 (96.0%) of the samples. The serogroups identified were O125 (6.0%), O111 (4.0%), O55 (2.0%) and O119 (2.0%). Three (6.0%) and 1(2.0%) of the E.coli isolates were VTEC and ETEC, respectively. Most frequent resistance was observed to the following antimicrobials: cephalothin (60.0%), nalidixic acid (40.0%), doxycyclin (33.0%), tetracycline (31.0%) and ampicillin (29.0%).

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