**3.2 Stool sample**

Each stool sample was streaked onto Hecktoen agar and pre-enriched in selenite broth at 37 °C for 24 h. The pre-enrichment sample was streaked onto Hecktoen agar, and after incubation at 37 °C for another 24 h, the suspicious colonies were identified with biochemical test (as mentioned above).
