Surveillance of stool samples for the presence of Enterobacter sakazakii among Korean people

Purpose: Enterobacter sakazakii (E. sakazakii) infections are an important cause of life-threatening meningitis, septicemia, and necrotizing enterocolitis in infants. Dried infant formula milk is an important vehicle for E. sakazakii infection. E. sakazakii was isolated in Korea from dried infant formula milk. Although E. sakazakii infection of infants may occur in Korea, its prevalence has not yet been documented. Therefore, we determined the prevalence of E. sakazakii and documented symptoms. Materials and Methods: Between March and October 2006, 1,146 stool samples were collected from patients at Uijeongbu St. Mary's Hospital. Each fecal swab was dissolved in 10 mL of buffered peptone solution, and enriched culture was streaked onto Druggan-Forsythe-Iversen (DFI) agar. Presumptive E. sakazakii colonies that exhibited a blue-green color during culture on DFI medium were selected. The identity of colonies that developed yellow pigment during culture on TSA was determined using the Vitek system and PCR. Results: We isolated 4 E. sakazakii strains whose 16S rRNA sequence alignments had a similarity of 99% with those of 3 E. sakazakii ATCC strains. Conclusion: This is the first report on isolation of E. sakazakii from stool samples and to document the symptoms of Korean patients.