To isolate the pathogen, the remainder of the BPW cultures of the PCR-positive samples were streaked onto deoxycholate-hydrogen sulfide-lactose agar (Eiken Chemical Co., Tokyo, Japan) and incubated at 37°C overnight. Presumptive E. albertii colonies (50–100/sample) were isolated on nutrient agar plates (Eiken Chemical Co.) and incubated at 37°C overnight. The isolates were then re-tested using the PCR method described above. The confirmed PCR-positive isolates were then examined for fermentation of glucose, motility and hydrogen sulfide production on triple-sugar iron agar (Eiken Chemical Co.) and sulfide indole motility medium agar (Eiken Chemical Co.)
Isolates with positive glucose fermentation, negative motility and negative hydrogen sulfide production test results were then confirmed as E. albertii using multi locus sequence typing (MLST) as previously described [9]. Sequences of isolates in the present study were submitted to MLST databases run by the University of Warwick (http://mlst.warwick.ac.uk/mlst/, accessed 5th October, 2014), and isolates were assigned sequence types (ST) defined by the database (http://mlst.warwick.ac.uk/mlst/dbs/Senterica/GetTableInfo_html). Allele sequences for each isolate were then concatenated in the order adk − fumC − gyrB − icd − mdh − purA − recA, for a final composite length of 3,423 bp. The concatenated sequences were aligned using ClustalW [21], and a phylogenetic tree was constructed using the neighbor-joining method in MEGA5 software [20] to compare the results with other published STs.