Pulsed-Field Gel Electrophoresis Analysis of a Salmonella london Outbreak in Neontes

Abstract

Purpose : Salmonella species is one of the most common causative organisms of acute gastroenteritis in neonates. There have been some reports of outbreaks of Salmonella species in neonates, but none was caused by Salmonella london. Pulsed-Filed Gel Electrophoresis (PFGE) was used to compare and analyze 6 isolates of S. london from the formula-fed neonates in Chunan city from late June through early July in the year of 2000. Methods : In June and July 2000, we performed culture from blood and stool of 5 patients who admitted in Soonchunhyang Chunan Hospital. We performed a molecular analysis based on plasmid profile and pulsed-filed gel electrophoresis (PFGE). We reviewed their hospital records retrospectively. The affected babies were isolated during hospitalization and discharged home as soon as possible. In addition, hand washing, cleaning, and disinfection were intensified to prevent the spread to other babies. Results : We isolated 6 strains of S. london from stool or blood samples of five patients, who were 9 to 14 days old and had fever, diarrhea, poor feeding or weight loss. The specimens for culture of Salmonella species were obtained on the admission day of every patient. All Salmonella species showed the same biochemical reactions as slant/ butt on KIA －/＋, H2S ＋, gas ＋, motility ＋, indole －, ornitine decarboxylase ＋, lysine decarboxylase ＋, and citrate utilization ＋. They also showed agglutinations by Salmonella serogroup E antisera. They were susceptible to all antimicrobial agents tested by NCCLS disk diffusion method. The clonality of isolates was confirmed by PFGE after digestion with Xba I and revealed the similar band patterns of S. london. Conclusion : We have reported the outbreak of S. london of the formula-fed neonates in Chunan city from late June through early July in the year of 2000. Pulsed-Filed Gel Electrophoresis (PFGE) would be essential for the molecular and epidemiologic studies for the outbreaks caused by Salmonella species.