Two novel analytical methods based on polyclonal and monoclonal antibodies for the rapid detection of Cronobacter spp.: Development and application in powdered infant formula

- We produced mAbs and pAbs against the immunogen Cronobacter ATCC29544.
- We established an indirect ELISA specific for Cronobacter spp. based on pAbs.
- We established a sandwich ELISA specific for Cronobacter sakazakii based on mAbs and pAbs.
- We applied these novel ELISAs to the detection of Cronobacter spp. in PIF.

Cronobacter spp. are opportunistic pathogens, and infections are associated with a high mortality rate. In the current study, monoclonal antibodies (mAbs) and polyclonal antibodies (pAbs) were generated using heat-inactivated C. sakazakii strain ATCC29544 as the immunogen. Following assay optimization, an indirect enzyme-linked immunosorbent assay (ELISA) based on pAbs and a sandwich ELISA based on mAbs and pAbs were established for the detection of Cronobacter spp. The indirect ELISA detected all species of Cronobacter assayed, and the limit of detection (LOD) was established as 105 cfu/mL. In contrast, the sandwich ELISA was specific for C. sakazakii and had greater sensitivity than the indirect ELISA (LOD of 2 × 104 cfu/mL). Following 10 h of enrichment, Cronobacter spp. were detected using either of the two analytical methods in samples inoculated with 1 cfu/100 g powdered infant formula (PIF). The results from this study demonstrated that both of these novel ELISAs were specific, sensitive, and rapid assays for the screening of pathogenic Cronobacter spp. in PIF.