Protective Effect of Recombinant Proteins of Cronobacter Sakazakii During Pregnancy on the Offspring.

Cronobacter sakazakii is a food-borne pathogen carried in milk powder that can cause severe bacteremia, enterocolitis, and meningitis in newborns, which can lead to death of newborns. Preventing infection by this pathogen is significant to the health of newborns. Since infants and young children are the main target group of C. sakazakii, it is considered that maternal immunity can enhance the protection of newborns. Previous studies showed that two proteins of C. sakazakii (GroEL and OmpX) exhibited high expression levels and elicited strong immune reactions, suggesting their potential as vaccine candidates. In this study, GroEL and OmpX were recombinantly expressed in Escherichia coli and purified as immunogens to immunize pregnant rats. Three days after birth, the progeny were challenged with C. sakazakii to determine the protective effect of maternal immunity on the offspring. The results showed that immunization during pregnancy decreased bacterial load in the brain and blood, reduced brain and intestine damage, and significantly increased specific antibody titers in the offspring. Immunization with the recombinant proteins significantly increased cytokine levels in the serum of the progeny. The group whose mothers were immunized with OmpX produced more IL-4, while the group whose mothers were immunized with GroEL produced more IFN-γ, indicating that the immunogens enhanced the Th2 and Th1 responses, respectively. However, although the immune response was induced by both proteins, only the offspring of the pregnant rats immunized with OmpX or OmpX/GroEL mixture showed delayed death, possibly because immunization with OmpX led to a stronger humoral immune response in the offspring, suggesting that OmpX was a better vaccine candidate than GroEL. This study first reported that exposure to C. sakazakii proteins during pregnancy could improve the offspring's ability to resist infection caused by this pathogen.

[Application of hemoperfusion in children with acute tetramine poisoning].

OBJECTIVE: To investigate the efficacy of hemoperfusion treatment in children with acute tetramine poisoning. METHODS: Thirty-two children aged from 1 to 8 years ( mean 4.6+/-2.4 years) with acute tetramine poisoning received hemoperfusion treatment. Serum tetramine concentrations were measured by gas chromatography before hemoperfusion, 1 and 2 hrs after hemoperfusion initiation and 12 and 24 hrs by the end of hemoperfusion. The median time for full recovery of consciousness and the time to seizure control were observed. RESULTS: Seventeen children received hemoperfusion treatment for one time, 12 for twice, 2 for 4 times and 1 for 3 times. Twenty- seven (84%) cases recovered, 2 (7%) cases improved and 3 (9%) cases died of multi-organ failure. The serum tetramine concentrations 1 and 2 hrs after hrmoperfusion initiation were significantly lower than those before hemoperfusion (P<0.01). The serum tetramine concentrations 12 and 24 hrs by the end of hemoperfusion were also significantly lower than those before hemoperfusion (P<0.01). The median time for full recovery of consciousness and the time to seizure control were 5.4+/-4.2 and 10.1+/-7.3 hrs, respectively. CONCLUSIONS: Hemoperfusion treatment is effective for acute tetramine poisoning in children.