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Molecular characterisation and stress tolerance of E scherichia coli isolated from dairy and dried milk‐related products
Author(s) -
ElSharoud Walid M.,
Yassin Mona A.,
Ahmed Salwa F.
Publication year - 2015
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.12646
Subject(s) - escherichia coli , ampicillin , toxin , microbiology and biotechnology , biology , phylogenetic tree , antibiotics , food science , enterotoxigenic escherichia coli , drug resistance , antibiotic resistance , enterotoxin , chemistry , gene , biochemistry
Summary This study characterised the phylogenetic groups, pathotypes, antibiotic resistance and stress response of E scherichia coli isolates recovered from dairy and dried milk‐related products. A total of 54 isolates of E . coli were recovered from thirty‐three of 180 samples (18%) of these products. Representatives from all the four phylogenetic groups of the organism were identified, although groups A and B1 dominated groups B2 and D. Enterotoxigenic E. coli (ETEC) strains producing heat‐labile toxin (LT) could be detected among the isolates and were found to be associated with the Kariesh cheese. Escherichia coli isolates showed single‐drug and multiple‐drug resistance to ß‐lactams and other antibiotic classes. The bla TEM‐1 gene was found to be associated with resistance to ampicillin but not to cephalothin. Escherichia coli survived heating at 50 and 55 °C for 60 min, but was undetectable after only 10 min of exposure to 60 °C. It also survived in the presence of 6% and 8% salt for 96 h and in pH 4.0 for 72 h.