Table 5.

Uncertainties associated with assessing the public health risk from Cronobacter.

• Cases of infection that are missed because of inadequate microbiological methods for detection, isolation and/or identification

• Cases that are not reported to local, state and federal health agencies

• Cases that are identified as Cronobacter infection or colonization but are not because of mis-identification of the bacterium that was isolated from the clinical specimen

• Differentiation of infection vs. colonization

• Incorrect use of the term “Cronobacter infection” – in most instances the correct usage is “a clinical microbiology isolate of Cronobacter which was not further studied as to infection vs. colonization”

• Incubation period, infectious dose and strain infectivity in neonatal meningitis and other human infections

• Incorrect assumptions in causation analysis

• Possible role of throat colonization in neonatal meningitis as a means of multiple inoculation of the intestinal tract (as has been shown for Yersinia enterocolitica serotype O3)

• Inaccurate medical records – Example: a twin whose record said he was not fed powdered infant formula, but he probably was because of a three different identification errors (switches) of his records with those of his twin brother who was fed a powdered infant formula)

• Animal models for infectious dose and incubation period have many limitations when extrapolated to human infections

• Unknown importance environmental reservoirs

• The original source of the Cronobacter organism isolated in the “blender-associated cases”

• The original source of the Cronobacter organism in the “Nursery water cases”

• Importance of strains destroyed, rather than saved, by the powdered infant formula industry