Identification and phylogenetic analysis of Xenorhabdus isolates
The 69 Xenorhabdus isolates were identified as X. stockiae (n = 52), closely related to X. stockiae (n = 14), and closely related to X. miraniensis (n = 3). These findings were replicated in a phylogenetic analysis. A maximum likelihood tree reconstructed using the 69 Xenorhabdus sequences together with sequences downloaded from GenBank is shown in Figure 2. The Thai isolates fell into four distinct groups. Group 1 included 52 study isolates and a sequence from the NCBI database derived from X. stockiae. Group 2 included 13 study isolates but no reference sequence, and group 3 included one study isolate that was most closely related to group 2. The fourth cluster contained the remaining 3 Thai isolates, which were most closely related to X. miraniensis. Geographical mapping of the largest phylogenetic group containing the 52 X. stockiae isolates demonstrated that these were recovered from diverse geographical locations including 7 provinces (Table 2), as were the 13 isolates belonging to group 2.