Can Enterococcus faecium prevent NEC in preterm infants?: A systematic review and meta-analysis.

OBJECTIVE: Previous some systematic reviews reported that probiotics may benefit the prevention of NEC in preterm infants. But dissimilar bacterial strains and taxa used in included studies possibly result in bias. There is not a rounded systematic review which has estimated the benefit and safety of Enterococcus faecium to prevent NEC in preterm infants to date before we conducted. METHODS: This systematic review of randomized controlled trials and retrospective studies analyzing the benefit of Enterococcus faecium to prevent NEC in preterm infants was performed using PubMed, Web of Science, Cochrane Library, EMBASE, Wanfang data and China National Knowledge Infrastructure databases from inception to April 14, 2023. The search terms were "preterm" AND "necrotizing enterocolitis" AND "Enterococcus faecium OR probiotics." Studies reporting NEC involving preterm infants who were given Enterococcus faecium were included in this systematic review. A sensitivity analysis was conducted to assess the stability of results. A funnel plot was generated to identify publication bias. Two authors appraised studies quality and extracted data independently. This work has been reported according with preferred reporting items for systematic reviews and meta-analyses and assessing the methodological quality of systematic reviews. Statistical analysis was conducted using Review Manager 5.3 software. Risk ratio (RR) with 95% confidence intervals (CI) was calculated and analyzed. RESULTS: Seven studies (N = 1487 participants) were included in this systematic review, and 6 randomized, controlled trials (N = 1237 participants) were included in the meta-analysis. Comparing with the control groups, the Enterococcus faecium groups had a significant decline in the incidence of NEC Bell stage II or higher (RR: 0.3138, 95% CI: 0.1983-0.4965; P < .00001; 6 studies, n = 1237) and infection (RR: 0.4818, 95% CI: 0.2950-0.7869; P = .004; 3 studies, n = 710). CONCLUSIONS: Enterococcus faecium is effective and safe in preventing NEC (Bell stage II or higher) in preterm infants. But all studies included came from China. The dosages and durations of taking Enterococcus faecium were various.

Effect of colostrum on immunoglobulin A levels among premature infants: a meta-analysis / 预防医学

Objective@#To systematically evaluate the effect of colostrum on immunoglobulin A (IgA) levels among premature infants, so as to provide the evidence for improving premature infants' health with colostrum feeding.@*Methods@#Randomized controlled clinical trials (RCTs) or controlled clinical trials (CCTs) pertaining to the effect of colostrum and IgA levels among premature infants were retrieved in national and international databases from inception to September 30, 2022, including CNKI, Wanfang Data, PubMed and Web of Science. Standardized mean difference (SMD) was used as an effect index for meta-analysis. The robustness of the results was evaluated using sensitivity analysis, and the publication bias was evaluated using Begg's test, Egger's test and funnel plot.@*Results @#A total of 650 publications were retrieved initially, and 10 studies were finally included, including 9 RCTs and one1 CCT, with 677 participants. Meta-analysis showed higher secretory salivary secretory IgA levels among premature infants with colostrum feeding than among controls (SMD=0.49, 95%CI: 0.08-0.89), and there were no significant differences between groups in terms of urinary secretory IgA levels (SMD=0.19, 95%CI: -0.39-0.77) or blood IgA levels (SMD=0.29, 95%CI: -0.01-0.59). Sensitivity analysis showed robustness of meta-analysis results, and no publication bias was examined.@*Conclusion@#Colostrum feeding may increase salivary secretory IgA levels among premature infants; however, it has no effect on urine salivary secretory IgA levels or blood IgA levels.

Effects of Different Environmental Factors on the Growth and Bioactive Substance Accumulation of Porphyridium purpureum.

Genus Porphyridium is a primitive single-celled red algae widely distributed in seawater, freshwater, and moist soil. It can synthesize bioactive substances such as phycoerythrin, extracellular polysaccharides and polyunsaturated fatty acids during the growth process. In this paper, the culture and bioactive substance yield of Porphyridium purpureum were studied by setting salinity, nitrogen-to-phosphorus ratio, and pH at different gradient levels. The results showed that the optimal conditions for the growth of P. purpureum were salinity 34 ppt, nitrogen-to-phosphorus ratio 169:1, and pH 8; the optimal conditions for obtaining the polysaccharides were salinity 17 ppt, nitrogen-to-phosphorus ratio 14:1, and pH 8; the optimal conditions for obtaining phycoerythrin were salinity 17 ppt, nitrogen-to-phosphorus ratio 68:1, and pH 8; the optimal conditions for obtaining the lipids were salinity 34 ppt, nitrogen-to-phosphorus ratio 1:1, and pH 8. In actual production applications, culture conditions should be set according to different product accumulation purposes in order to achieve the optimal production efficiency.