Culture-proven neonatal sepsis in Japanese neonatal care units in 2006-2008.

BACKGROUND: Recent Japanese epidemiology of neonatal sepsis and its predominant pathogens has not been reported. It is also unknown whether there are center differences in the incidence of neonatal sepsis, including early-onset sepsis (EOS) and late-onset sepsis (LOS) in Japan. OBJECTIVES: To investigate the morbidity and characteristics of neonatal sepsis in recent years and the differences in the incidence of sepsis among Japanese neonatal care units. METHODS: We retrospectively collected the data of newborn infants with culture-proven sepsis that occurred in five Japanese centers of perinatal care from 2006 to 2008. The incidence of sepsis was calculated, including EOS and LOS, and compared among centers. RESULTS: Morbidity from sepsis occurred in 51/6,894 (0.74%) infants. The incidence of EOS and LOS was 0.13 and 0.61%, respectively. The incidence of total sepsis and LOS in infants <1,000 g of birth weight was significantly higher than that in infants who weighed >1,000 g at birth, whereas there were no significant differences in the incidence of EOS between the different birth weights. Methicillin-resistant Staphylococcus aureus was the most common pathogen involved in morbidity and mortality of neonatal sepsis. Significant center differences were observed in the incidence of LOS, but not EOS. CONCLUSIONS: The majority of culture-proven neonatal sepsis is LOS, which differs among centers, especially in infants who weigh <1,000 g at birth in Japan. We consider that it is important to control nosocomial infection in newborn care units to further reduce the morbidity of neonatal sepsis in Japan.

Genetically modified Bifidobacterium displaying Salmonella-antigen protects mice from lethal challenge of Salmonella Typhimurium in a murine typhoid fever model.

We developed a novel vaccine platform utilizing Bifidobacterium as an antigen delivery vehicle for mucosal immunization. Genetically modified Bifidobacterium longum displaying Salmonella-flagellin on the cell surface was constructed for the oral typhoid vaccine. The efficiency of this vaccine was evaluated in a murine model of typhoid fever. We then orally administered 2.5 × 10(7) CFU of the recombinant Bifidobacterium longum (vaccine) or parental Bifidobacterium longum, or PBS to BALB/C mice every other day for 2 weeks. After the administration, a total of 42 mice (14 mice in each group) were challenged with Salmonella Typhimurium (1.0 × 10(7) CFU/mouse). While 12 mice in the PBS group, and 9 in the parental Bifidobacterium longum group died (median survival: 14 and 25 days), only two in the vaccine group died. These data support that our genetically modified Bifidobacterium antigen delivery system offers a promising vaccine platform for inducing efficient mucosal immunity.