Characterization of Escherichia fergusonii and Escherichia albertii isolated from water

Abstract

Aims: The aim of this study was to characterize Escherichia fergusonii and Escherichia albertii isolated from water. Methods and Results: The characterization of E. fergusonii and E. albertii isolated from water was determined using an Escherichia coli-specific uidA PCR, a tuf PCR, and with phylogenetic analysis using three housekeeping genes (adk, gyrB, and recA) from the E. coli MLST scheme, selected for their ability to discriminate among all Escherichia species. Among the 527 isolates tested, 25 (4Á7%) were uidA PCR negative and tuf PCR positive. Phylogenetic analysis using adk, gyrB and recA genes showed that 6, 18 and 1 of these 25 non-E. coli Escherichia spp. isolates grouped with reference strains of E. fergusonii, E. albertii, and E. coli, respectively. Finally, the 25 non-E. coli Escherichia spp. strains isolated were investigated for the presence of pathogenic factors, comprising intimin (eae gene), cytolethal distending toxin (cdtB gene) and shiga toxin (stx gene). With the PCR primers used, the presence of eae and stx genes was not detected. However, cdtB genes types I/IV were detected for 3 (16Á7%) E. albertii strains, whereas 15 of 18 (83Á3%) possessed the cdtB gene types II/III/V. Conclusions: These results showed that MLST scheme allows a more accurate identification of non-E. coli species than phenotypic tests. We also showed that E. fergusonii and E. albertii represent, respectively, 0Á8 and 2Á5% of all Escherichia species isolated and the pathogenic cdtB genes were present in 83Á3% of these strains. Significance and impact of the study: The data presented in this study provided an efficient way to correctly identify non-E. coli species contributing to our understanding of the risks associated with Escherichia species in water consumed by humans and animals. Furthermore, the results give an insight about the natural habitats of these species.

Evaluating the Occurrence of Escherichia albertii in Chicken Carcass Rinses by PCR, Vitek Analysis, and Sequencing of the rpoB Gene

“…We identified different profiles based on rpoB types, but no phenotype was 100% consistent for all isolates. These results agree with those of Maheux et al (20) and were not surprising because the Vitek-2 system has not been optimized to detect E. albertii. E. albertii was initially described as nonmotile, but we identified motile isolates using SIM medium.…”

“…It is possible that rare sequences of these genes exist in the E. albertii populations that are not detected with the PCR primers used here. Recently, new eae variants of E. albertii isolates have been described by Oh et al (7) and Maheux et al (20). Also, Toth et al found new variants of cdt (18).…”

“…Ooka et al (8) added intimin subtyping and PCR analysis of Shiga toxin genes to detect E. albertii from a population previously described as intimin-positive E. coli. Isolates of E. albertii are clearly distinguished from E. coli by MLST (6,8,20,21).New methods for identification of E. albertii are needed to determine its prevalence and pathogenicity in people and animals. With the availability of sequencing, a definitive sequence-based approach for identification of E. albertii is possible.…”

“…Ooka et al (8) added intimin subtyping and PCR analysis of Shiga toxin genes to detect E. albertii from a population previously described as intimin-positive E. coli. Isolates of E. albertii are clearly distinguished from E. coli by MLST (6,8,20,21).…”

Multiplex polymerase chain reaction for identification of Escherichia coli , Escherichia albertii and Escherichia fergusonii

“…Polymerase Chain Reaction (PCR) or MLST based tests for specific genes for identification of Escherichia spp. have been described (Ooka et al, 2013, Maheux et al, 2014, Maheux et al, 2014). A PCR that detects the uidA gene (encoding the b–glucuronidase enzyme) is frequently used to identify E. coli (Bej et al, 1991, (Frahm and Obst, 2003), Pavlovic et al, 2010).…”