Enterobacter sakazakii: infectivity and enterotoxin production in vitro and in vivo

• Published in: Journal of food protection Vol. 66; no. 3; pp. 370 - 375
• Main Authors: Pagotto, F.J, Nazarowec-White, M, Bidawid, S, Farber, J.M
• Format: Journal Article
• Language: English
• Published: Des Moines, IA International Association of Milk, Food and Environmental Sanitarians 01.03.2003
• Subjects: Administration, Oral; animal models; Animals; Animals, Suckling; bacterial contamination; bacterial motility; Bacteriology; bioassays; Biological and medical sciences; biological production; cell culture; cell lines; Cells, Cultured; Cronobacter sakazakii; dried foods; Enterobacter - metabolism; Enterobacter - pathogenicity; enterotoxins; Enterotoxins - biosynthesis; food contamination; Food industries; Food Microbiology; food pathogens; Fundamental and applied biological sciences. Psychology; Humans; in vitro studies; in vivo studies; Infant; Infant Food - microbiology; infant formulas; Injections, Intraperitoneal; intraperitoneal injection; lethal dose; Lethal Dose 50; meningitis; Meningitis, Bacterial - etiology; Mice; Microbiology; oral administration; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; suckling; Virulence; Pathogenesis; Rodentia; Adrenal cortex; Monkey; Suckling animal; In vitro; CHO cell line; Kidney; Toxin; In vivo; Vertebrata; Cell line; Mammalia; Enterobacter; Mouse; Infant food; Infectivity; Primates; Enterotoxin; Bacteria; Hamster; Enterobacteriaceae
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-66.3.370

Enterobacter sakazakii has been implicated as the causal organism in a severe form of neonatal meningitis, with reported mortality rates of 40 to 80%. Dried infant formula has been identified as a potential source of the organism in both outbreaks and sporadic cases. In this study, clinical and foodborne isolates of E. sakazakii were evaluated for enterotoxin production by the suckling mouse assay. In addition, suckling mice were challenged both orally and by intraperitoneal injection. Of 18 E. sakazakii strains evaluated, four were found to test positive for enterotoxin production. All strains of E. sakazakii were lethal to suckling mice at 10(8) CFU per mouse by intraperitoneal injection, while two strains caused death by the peroral route. In in vitro assays, CHO, Vero, and Y-1 cells demonstrated both cell lysis and rounding when exposed to E. sakazakii strain LA filtrates. This is the first report describing any putative virulence factors of E. sakazakii.