Evaluation of Virulence Factor Profiling in the Characterization of Veterinary Escherichia coli Isolates

Abstract

Escherichia coli has been used as an indicator organism for fecal contamination of water and other environments and is often a commensal organism in healthy animals, yet a number of strains can cause disease in young or immunocompromised animals. In this study, 281 E. coli isolates from bovine, porcine, chicken, canine, equine, feline, and other veterinary sources were analyzed by BOXA1R PCR and by virulence factor profiling of 35 factors to determine whether they had utility in identifying the animal source of the isolates. The results of BOXA1R PCR analysis demonstrated a high degree of diversity; less than half of the isolates fell into one of 27 clusters with at least three isolates (based on 90% similarity). Nearly 60% of these clusters contained isolates from more than one animal source. Conversely, the results of virulence factor profiling demonstrated clustering by animal source. Three clusters, named Bovine, Chicken, and Porcine, based on discriminant components analysis, were represented by 90% or more of the respective isolates. A fourth group, termed Companion, was the most diverse, containing at least 84% of isolates from canine, feline, equine, and other animal sources. Based on these results, it appears that virulence factor profiling may have utility, helping identify the likely animal host species sources of certain E. coli isolates.

Genetic relatedness of commensal Escherichia coli from nursery pigs in intensive pig production in Denmark and molecular characterization of genetically different strains

“…Of note is also that the gene iss (involved in serum resistance), usually associated with poultry disease and suggested to be a gene used to separate chicken isolates from the majority of isolates from mammalian sources (David et al . ) was found in 14 different profiles. The gene pic (serine protease), present in one isolate, is known to be associated with urinary tract isolates (Restieri et al .…”

Evaluation of Incompatibility Group I1 (IncI1) Plasmid-Containing Salmonella enterica and Assessment of the Plasmids in Bacteriocin Production and Biofilm Development

“…The presence of plasmid-associated genes within the host may also impact the susceptibility to bacteriocins, expression of plasmid-associated siderophores, salmochelin, and aerobactin, by E. coli have been shown to limit the impact of Salmonella in the gastrointestinal tract (54). Interestingly, the two isolates that inhibited the greatest number of E. coli (N134 and N136) carried an IncFIB plasmid in addition to IncI1 and the veterinary E. coli strains that they inhibited (542 and 590) lacked the aerobactin operon, while the four (164, 524, 550, and 586) not inhibited were positive for the aerobactin operon (29), which is commonly carried by IncFIB plasmids (39). The reason for this dichotomy could either be due to E. coli carrying an IncFIB-encoded immunity protein or having the aerobactin machinery to acquire iron without needing to highly express the enterobactin receptor.…”

“…E. coli J53 (27, 28) was used as a recipient strain for E. coli transconjugants generated in a previous study (24), but further characterized here. The following strains from ATCC or the FDA NCTR culture collection were used to assess their susceptibility to bacteriocins produced by wildtype Salmonella isolates and transconjugants: Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 29213, S. enterica serovar Typhimurium ATCC 14028, Klebsiella pneumoniae N950, Enterococcus cloacae N1075, and the following E. coli strains ATCC 25922, N734 ( E. coli O157:H7), 164, 524, 542, 550, 586, and 590 (29).…”

Impact of Plasmids, Including Those EncodingVirB4/D4 Type IV Secretion Systems, on Salmonella enterica serovar Heidelberg Virulence in Macrophages and Epithelial Cells

“…In addition, plasmids were isolated from strain 163 using the methods described by Wang and Rossman [29] and the Wizard Plus SV Minipreps kit (Promega, Madison, WI). The isolated plasmid DNA was transformed into E. coli One Shot TOP10 cells as described by the manufacturer and positive transformants were selected and screened for the presence of each of the plasmids using PCR primers and conditions previously described for bla CMY (IncA/C marker), s itA (IncFIB marker) and virB4 (VirB/D4 marker) [30,31]. Plasmids were also isolated from the transconjugant and transformant strains [29] and separated as described previously [8] to further confirm the presence of the plasmids in the strains evaluated.…”