Application of CRISPR in evolution analysis, detecting and typing, virulence and antibiotic resistance regulation in food-borne pathogens / 生物工程学报

Clustered regularly interspaced short palindromic repeats (CRISPR) and its associated protein gene system can limit the horizontal gene transfer, thereby effectively preventing the invasion of foreign gene elements such as bacteriophages. CRISPR arrays of different bacteria are diverse. Based on the differences in the CRISPR system, this review summarizes the application of CRISPR in food-borne pathogen evolution analysis, detection and typing, virulence and antibiotic resistance in recent years. We also address bacterial detection typing method developed based on the characteristics of CRISPR arrays and the association of CRISPR with virulence and drug resistance of food-borne pathogens. The shortcomings of CRISPR in evolution, detection and typing, virulence and resistance applications are analyzed. In addition, we suggest standardizing CRISPR typing methods, improving and expanding the CRISPR database of pathogenic bacteria, and further exploring the co-evolution relationship between phages and bacteria, to provide references for further exploration of CRISPR functions.

Fecal microbiota transplantation from growing pigs with different feed efficiency to pseudo-germ-free mice can result in reappearance of the original phenotype / 中国实验动物学报

Objective The aim of this experiment was to explore the effect and mechanism of intestinal microbiota on shaping the growth performance by fecal microbiota transplantation from pigs to pseudo-germ-free mice. Methods Thirty-six barrows with a similar initial body weight of 30 kg were raised for 42 days(ad libitum)within individual metabolic cages. Feed intake and body weight of each pig were recorded every week to calculate the feed conversion rate and average daily gain. At the end of the experiment,feed conversion ratio and average daily gain were integrated to divide the pigs into 3 groups, namely, high growth performance(HP), moderate growth performance(MP)and low growth performance(LP)groups. Feces were collected to calculate the total intestinal nutrient digestibility and prepare for fecal microbiota transplantation to pseudo-germ-free mice, which were induced with several antibiotics for four weeks. Fecal microbiome structure was assayed by profiling V3-V4 region of the 16S rRNA gene. Results Fecal microbiota transplantation from pigs to pseudo-germ-free mice resulted in reappearance of the original phenotype. Compared with the LP pigs, the microbial species richness and microbial diversity in feces were higher in the HP pigs. The HP pigs had improved digestibility of gross energy(P =0.01)and higher abundance of Methanobrevibacter. Enterococcus and Akkermansia were also more abundant in the recipient pseudo-germ-free mice from the HP pigs which may be correlated with a high energy utilization. Conclusions Fecal microbiota transplantation from pigs to mice results in reappearance of the original phenotype and microbial species richness,microbial diversity,and their growth ability. Different nutritional metabolism is shown among pigs with different feed efficiency and the HP pigs have improved energy utilization(P=0.01). At the same time, the bacteria correlated with high energy utilization are more abundant in feces of HP pigs than in LP pigs.