A Virulence and Antimicrobial Resistance DNA Microarray Detects a High Frequency of Virulence Genes in Escherichia coli Isolates from Great Lakes Recreational Waters

Abstract

Escherichia coli is generally described as a commensal species with occasional pathogenic strains. Due to technological limitations, there is currently little information concerning the prevalence of pathogenic E. coli strains in the environment. For the first time, using a DNA microarray capable of detecting all currently described virulence genes and commonly found antimicrobial resistance genes, a survey of environmental E. coli isolates from recreational waters was carried out. A high proportion (29%) of 308 isolates from a beach site in the Great Lakes carried a pathotype set of virulence-related genes, and 14% carried antimicrobial resistance genes, findings consistent with a potential risk for public health. The results also showed that another 8% of the isolates had unusual virulence gene combinations that would be missed by conventional screening. This new application of a DNA microarray to environmental waters will likely have an important impact on public health, epidemiology, and microbial ecology in the future.

Occurrence of Intestinal and Extraintestinal Virulence Genes in Escherichia coli Isolates from Rainwater Tanks in Southeast Queensland, Australia

“…coli pathotypes such as STEC, EPEC, ETEC, and ExPEC and their associated VGs were selected in this study, as other studies have reported the presence of these pathotypes, originating from sewage and/or animal feces, in environmental water (23,24,25,38,46). Overall, 30 (15%) of 200 isolates from eight tanks were positive for the eaeA gene, which belongs to STEC or EPEC (25).…”

Pathotype and Antibiotic Resistance Gene Distributions of Escherichia coli Isolates from Broiler Chickens Raised on Antimicrobial-Supplemented Diets

“…Prehybridization and hybridizations were performed as previously described (19), with the following modifications: hybridizations were performed using a Slide Booster hybridization work station (model SB800; Advalytix, Germany), and scanning was performed using a ScanArray Lite fluorescent microarray analysis system (Perkin-Elmer, Mississauga, ON, Canada) with images scanned at 5-m resolution and laser power set to 95%. Acquisition of fluorescent spots and quantification of fluorescent spot intensities were performed as described by Hamelin et al (19).…”

“…To this end, an E. coli DNA virulence microarray previously employed to assess the genotypes (virulence and antibiotic resistance genes) of E. coli strains isolated from different environmental ecosystems and from the chicken intestinal tract (1,10,19,20,33) was used. The aim of the present trial was to investigate the distributions of pathotypes and of virulence and antibiotic resistance genes in E. coli isolates from broilers fed with antimicrobial supplementation diets including bambermycin, penicillin, salinomycin, bacitracin, chlortetracycline, virginiamycin, monensin, and narasin.…”

Escherichia coli O157:H7-secreted cytotoxins are toxic to enterocytes and increase Escherichia coli O157:H7 colonization of jejunum and descending colon in cattle

“…The microarray used in this study is based on earlier published work , which contains 312 oligonucleotides (70 bases in length) targeting 183 virulence or virulence-related genes and 30 of the most common antimicrobial resistance genes found in Gramnegative bacteria (Hamelin et al 2006). …”

“…The tube was re-centrifuged as before and 150 mL of the supernatant containing DNA was removed and stored at (208C until used. Thawed lysate DNA was linearly amplified and labeled using the Bioprime † DNA Labeling System (Invitrogen Life Technologies, Burlington, ON) as described previously (Hamelin et al 2006). Briefly, 4 mL of RNase-treated supernatant were added to a final volume of 50 mL containing 20 mL of a random primer solution, 1 mL of persistent concentration DNA polymerase (Klenow fragment, 40 U mL…”