Antimicrobial Resistance Monitoring Of Chicken Escherichia Coli In Qinghai Province And Regulation Of β-1,3/1,6-Glucan On Chicken Gut Microbiota

Antimicrobial resistance(AMR)may lead to worldwide epidemics through animal activities and natural transmission,posing a global public safety threat.In order to obtain the AMR of chicken-derived Escherichia coli in Qinghai Province,through the detection of antibiotic sensitivity and whole genome sequencing analysis of E.coli isolated and identified from chicken feces samples,we understood the AMR of chicken-derived E.coli and its genetic environment of mcr-1 gene in this area.Herein,375 stool samples were collected from 12 poultry farms in Qinghai Province and 346E.coli strains were isolated,of which eight carried mcr-1.The AMR rates of the E.coli strains to ampicillin,amoxicillin/clavulanic acid and tetracycline were all above 90%,and the resistance rates to ciprofloxacin,cefotaxime,ceftiofur and florfenicol were above 70%.Multidrug-resistant strains accounted for 95.66%of the total isolates.12E.coli strains showed colistin resistance,from which a total of 46 AMR genes and 36virulence factors were identified through whole-genome sequencing.The mcr-1 gene resided on the Inc HI2,Inc I2-type and Inc Y-type plasmids,and mcr-1 was located in the nik A-nik B-mcr-1-pap2 gene cassette(three strains)or the pap2-mcr-1-ISApl1structure(one strain).Completed Inc I2-type plasmid p MCR4D31-3(62,259 bp),revealed that it may cause the horizontal transmission of mcr-1 and may increase the risk of its spread through the food chain.Taken together,the AMR of chicken-derived E.coli in plateau is of concern,suggesting that it is very necessary for us to strengthen the surveillance in various regions under the background of one health.In order to explore the effects of sulfamonomethoxine(SMM)addition into the drinking water during breeding on the structure of fecal bacterial community of laying hens.A total of 260 Hailan brown laying hens were randomly divided into two groups(group A: no SMM was added into drinking water;group B: SMM was added into drinking water),and fresh feces were collected on the 5th day of feeding.Then,no SMM was added in group B,and fresh feces were collected again after 7 days of feeding.The total DNA was extracted and sequenced by Illumiina Mi Seq platform.Based on the variable region of V3-V4 of 16 s r RNA were analyzed.The addition of SMM reduced the bacterial diversity and richness of the laying hens,but the abundance of Lactobacillus and Acinetobacter were significantly(P<0.05)increased.One week after stopping SMM addtiion,the bacterial diversity and richness of the laying hens recovered,and the abundance of Acinetobacter was significantly(P<0.05)decreased.lt was concluded that feeding SMM could change the structure of the intestinal community of laying hens,yet the intestinal community could recover after discontinuation of SMM feeding.The results increased insight into the harm of antibiotics and provided references for the standard use of antibiotics.It is of great significance to reduce the use of antibiotics and find new antibiotic substitutes in the breeding process.β-1,3/1,6-glucan as a prebiotic improves immune performance in animals.These functions are closely related to the effect ofβ-1,3/1,6-glucan on gut microbiota structure.However,the effect ofβ-1,3/1,6-glucan on the gut microbiota structure of broilers is unknown.This study was conducted to confirm the effects ofβ-1,3/1,6-glucan on the cecal microflora structure of yellow-feathered broilers.This study monitored the AMR level of E.coli in feces of yellow-feathered broilers by standard broth dilution method and mastered the AMR level of chickens selected.The effects ofβ-1,3/1,6-glucan on gut microbiota were investigated by 16S r RNA sequencing.The results showed that the number of isolated MDR E.coli strains accounted for 98.41%.At 14,21,and 28 days of age,supplemented of 0.2%,0.1%,and0.1%β-1,3/1,6-glucan in yellow feather broiler diets significantly altered gut microbial composition,and beneficial bacteria Alistipes,Bacteroides and Faecalibacterium were significantly increased.The abundance of Ruminococcus and Lachnospiraceae decreased significantly,related to the occurrence of inflammatory bowel diseases.These findings provide guidance and recommendations forβ-1,3/1,6-glucan as a broiler feed additive to improve the growth of broilers.