Specific detection of Cronobacter sakazakii in powdered infant formula using ssDNA aptamer.

ABSTRACT

Cronobacter sakazakii (C. sakazakii) is a foodborne pathogen associated with bacterial meningitis, sepsis, and necrotizing enterocolitis in premature and immuno-compromised infants. C. sakazakii is typically acquired by ingesting contaminated powdered infant formula (PIF). The growing demand for a safe food supply requires rapid detection of foodborne pathogens for delivering safe-to-consume food to consumers. In the present study, we isolated C. sakazakii-specific aptamers using a centrifugation-based partitioning method (CBPM) instead of systematic evolution of ligands by exponential enrichment (SELEX) process. Unlike SELEX, the CBPM reduces the evolution-loop time to obtain enriched probes, allowing the isolation of target-specific aptamers in a shorter time. The two aptamers (SC25 and SC45) isolated using the CBPM showed high affinity and specificity for C. sakazakii (Kd 34 and 66 nM). Among the two aptamers, SC25 aptamer detected efficiently C. sakazakii in PIF with less cross-reactivity. Our results indicate that the isolated aptamers could be used for detecting C. sakazakii in PIF and reducing the overall testing time compared with the conventional C. sakazakii detection method.