sakazakii by API 20E analysis were not confirmed by the other methods used including chromogenic, PCR and the final 16S rRNA sequence analysis. There have been several comparative studies performed to determine the usefulness of biochemical test strips and chromogenic as a diagnostic

tool for the identification of Cronobacter spp. However, these studies have given conflicting results [48, 50, 51] highlighting the need for other methods of confirmation such as molecular and the DNA sequencing methods. PCR analysis using eight different sets of primers from six separate studies [3, 13, 44–47] was used to help ascertain the identity of all the presumptive isolates. Standard ATCC strains (51329 and 29544) were used as a positive selleck compound control. Although eight sets of PCR primers from six different studies each claiming high sensitivity and specificity for detection and confirmation of Cronobacter spp. were used to ascertain the identity of the isolates in this study, only 13 isolates in addition to the ATCC (51329) strain were positive with all the primers (Table 5). The other 16 isolates did not give the predicted PCR product with at least one set of primers although they were identified as

Cronobacter spp. by other biochemical and/or

chromogenic methods. When the isolates were selleck products tested with the PCR primer sets, DNA was not amplified in a high number of strains especially www.selleckchem.com/products/iwr-1-endo.html when tested with the zpx (94 bp product) and gluB detecting only 21/31 and 2/5 respectively. The other sets of primers Etofibrate where more reliable detecting 25/31, 26/30, 27/30, 28/31 for gluA, Saka, SI and BAM primer sets respectively while both OmpA and SG appeared to be most reliable among the tested primer sets detecting 28/30 isolates. These observations suggest that there may be some sequence variability in the genes of these strains of Cronobacter spp. that were not observed by the reporting authors [3, 13, 47]. In addition, it is noteworthy to mention that strains Jor149, Jor154, Jor175, Jor 52, Jor170, Jor184, Jor51, Jor153B and Jor151 gave conflicting α-glucosidase activity (on α-MUG or DFI) that did not correspond with PCR results for the presence of gluA. All these strains had expressed α-glucosidase activity on both α-MUG and DFI, but were negative by PCR for the presence of gluA. Because of these results we tested some of the gluA PCR negative strains with primers that targeted gluB by using primers, parameters and PCR reaction conditions described by Lehner et al [47].