Rates of Recovery of Enterobacter sakazakii (Cronobacter spp.) from Powdered Infant Formula Using Both a Chromogenic Agar and Real-Time PCR: A Preliminary Study

Abstract

Although the number of incidences of illness caused by ingestion of the bacterial pathogen Enterobacter sakazakii (Cronobacter spp.) has dramatically declined, there remains a need for a robust isolation method to recover this microbe from powdered infant formula (PIF). The current method described in the FDA's Bacteriological Analytical Manual requires multiple steps, and 3-4+ days for complete analysis of PIF isolated E. sakazakii (Cronobacter spp.). We describe a bacteriological method including a one-step enrichment followed by plating on chromogenic agar for presumptive identification of E. sakazakii (Cronobacter spp.). Suspected colonies are confirmed by either biochemical analyses, or a Real-Time PCR-based assay. Using this method, E. sakazakii (Cronobacter spp.) in PIF can be isolated and identified within one day (24 hours).

Comparison of 10 Different Pre-Enrichment Broths for the Regeneration of Cronobacter spp. (Enterobacter sakazakii) Infected in Powdered Infant Formula

“…Recently, various efforts have been made to detect Cronobacter spp. (E. sakazakii) with the newly updated scientific technologies [14,15]. Generally, the process of bacterial isolation and identification requires a pre-enrichment step, so it is very important to select and use a pre-enrichment broth that is selective and specific for Cronobacter spp.…”

“…known to be associated with Cronobacter spp. (E. sakazakii)[1,2,[6][7][8][9][10][11][12][13][14][15][16][17]. Therefore, accurate and rapid detection and isolation of Cronobacter spp.…”

“…Therefore, accurate and rapid detection and isolation of Cronobacter spp. (E. sakazakii) from contaminated samples is very important[1,2,14,15,17]. According to the US FDA method, several steps must be taken to isolate and enumerate Cronobacter spp.…”