Culture media for the isolation of Cronobacter spp

Enterobacter sakazakii is a member of the Enterobacteriaceae and has been implicated in causing necrotising enterocolitis, as well as bacteraemia and meningitis in infants. In some cases, the infection has been linked to ingestion of infant formula milk (IFM) that has not been terminally sterilised. The nomenclature of E. sakazakii has been clarified and it has now been accepted as a group of six species comprising a novel genus, Cronobacter. Outbreaks in neonatal intensive care units resulting in relatively high case fatality rates and the recognition of IFM as a significant route of infection prompted the development of culture-based detection methods. Development of enrichment broths specific for Cronobacter spp., coupled to the use of fluorogenic and chromogenic substrates in culture media has significantly improved the sensitivity and specificity of methods. This review presents the history and rationale behind the currently available methods, and gives an overview of the principles involved in designing these microbiological media.