Molecular Characterization of Shiga Toxin-ProducingEscherichia coliIsolated from Ruminant and Donkey Raw Milk Samples and Traditional Dairy Products in Iran

Abstract

The aims of the current study were to detect the virulence factors and antibiotic resistance of Shiga toxin-producing E. coli, in animal milk and dairy products in Iran. After E. coli dentification with culture method, PCR assay were developed for detection of pathogenic genes, serotypes and antibiotic resistance genes of E. coli. Results showed that out of 719 samples, 102 (14.18%) were confirmed to be positive for E. coli and out of 102 positive samples, 17.64% were O26 and 13.72% were O157 and 1.96% were O91 and 1.96% were O145 serotypes. Totally, the prevalence of stx1 and papA genes were the highest while the prevalence of sfaS and fyuA were the lowest in the positive samples. PCR results showed that tetA, tetB were the highest (64.70%) and aac(3)-IV were the lowest (27.45%) antibiotic resistant genes in E. coli positive samples. Our study indicated that the isolated E. coli trains in these regions had a highest antibiotic resistance to tetracycline (58.82%) and the lowest to nitrofurantoin (3.92%). tetA gene and E. coli O157 serotype had highest and aac(3)-IV gene, and E. coli O145 serotype had a lowest frequency rates of antibiotics resistance genes, in the region.

Detection of virulence factors and antimicrobial resistance patterns in shiga toxin-producing Escherichia coli isolates from sheep

“…Healthy cattle are the main STEC reservoir, although some studies suggest that sheep also contribute significantly to the spread of these pathogens and consequently to the risk of human infection (Ferens & Hovde 2011). The EHEC serotype O157:H7 is the most relevant for humans and has been isolated worldwide from animal (meat and dairy) products and from feces of healthy sheep (Kumar et al 2012, Momtaz et al 2012.…”

Shiga-toxigenic Escherichia coli in ready-to-eat food staffs: Prevalence and distribution of putative virulence factors

“…These genes are responsible for bacterial adhesion, colonization and invasion into the gastric epithelial cells. [2][3][4][5][6][7][8] According to the uncertain role of STEC strains in ready to eat foods and lack of epidemiological and microbiological investigations in this field in Iran, the present research was done to study the prevalence and distribution of virulence factors in the STEC strains isolated from various types of ready to eat food samples. …”

“…AEEC strains are described by their ability to occur attachingand-effacing (A/E) lesions in the gastrointestinal tract of humans and animals. [2][3][4][5][6][7][8] STEC bacteria are responsible for severe clinical syndromes like Hemorrhagic Colitis (HC), Hemolytic Uremic Syndrome (HUS), bloody and non-bloody diarrhea and Thrombotic Thrombocytopenic Purpura (TTP). [2][3][4][5][6][7][8] Presence of latent virulence factors including Shiga toxins (stx1 and stx2), intimin (eaeA) and hemolysin (hlyA) in the STEC strains of food products make them dangerous pathogens for human health.…”

“…1 Among all pathogenic agents causing food-borne diseases, Escherichia coli (E. coli) strains had a significant position. [2][3][4][5][6][7][8] E. coli is a Gram-negative, non-sporulating, flagellated, rod-shaped and facultative anaerobic bacterium of the Enterobacteriaceae family. Shiga (vero) toxin (Stx)-producing E. coli (STEC) is a subdivision of a significant pathogenic group of this bacterium named enterohemorrhagic E. coli (EHEC).…”

“…Shiga (vero) toxin (Stx)-producing E. coli (STEC) is a subdivision of a significant pathogenic group of this bacterium named enterohemorrhagic E. coli (EHEC). [2][3][4][5][6][7][8] In the other hand, STEC strains are divided into two separate subtypes of EHEC and Attaching and Effacing E. coli (AEEC). EHEC strains are responsible for high morbidity and mortality.…”