Abstract
Shiga toxin-producing Escherichia coli (STEC) is an enteric pathogen that causes several gastrointestinal ailments in humans across the world. STEC’s ability to cause ailment is attributed to the presence of a broad range of known and putative virulence factors (VFs) including those that encode Shiga toxins. A total of 51 E. coli strains belonging to serogroups O26, O45, O103, O104, O113, O121, O145, and O157 were tested for the presence of nine VFs via PCR and for their susceptibility to 17 frequently used antibiotics using the disc diffusion method. The isolates belonged to eight different serotypes, including eight O serogroups and 12 H types. The frequency of the presence of key VFs were stx1 (76.47%), stx2 (86.27%), eae (100%), ehxA (98.03%), nleA (100%), ureC (94.11%), iha (96.07%), subA (9.80%), and saa (94.11%) in the E. coli strains. All E. coli strains carried seven or more distinct VFs and, among these, four isolates harbored all tested VFs. In addition, all E. coli strains had a high degree of antibiotic resistance and were multidrug resistant (MDR). These results show a high incidence frequency of VFs and heterogeneity of VFs and MDR profiles of E. coli strains. Moreover, half of the E. coli isolates (74.5%) were resistant to > 9 classes of antibiotics (more than 50% of the tested antibiotics). Thus, our findings highlight the importance of appropriate epidemiological and microbiological surveillance and control measures to prevent STEC disease in humans worldwide.
Highlights
Escherichia coli is ubiquitous in nature, often found in soil, water, food, human, and animal intestinal tracts
Shiga toxin-producing E. coli (STEC) possesses a broad range of virulence factors (VFs), which are encoded by chromosomal genes, and they are often located in pathogenicity islands (PAIs) or plasmids, with the production of stxs being the most crucial resulting in endothelial cell damage and possible hemolytic uremic syndrome (HUS) [7,8]
E. coli strains have been characterized by serotype and the presence and subtype of VFs, as well as other toxins and plasmid-associated adherence and virulence factors
Summary
Escherichia coli is ubiquitous in nature, often found in soil, water, food, human, and animal intestinal tracts. E. coli can act as a pathogen in a wide range of conditions, from enteric diseases to extraintestinal infections. Among the DEC, STEC includes the most dangerous strains and more than 400 serotypes that produce stxs have been identified, and this term was created since E. coli species possess the toxin, which is more or less identical to that produced by Shigella dysentery type I [6]. STEC possesses a broad range of virulence factors (VFs), which are encoded by chromosomal genes, and they are often located in pathogenicity islands (PAIs) or plasmids, with the production of stxs being the most crucial resulting in endothelial cell damage and possible hemolytic uremic syndrome (HUS) [7,8].
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