Invited review: Antimicrobial resistance in bovine mastitis pathogens: A review of genetic determinants and prevalence of resistance in European countries

Antimicrobial resistance is an urgent and growing problem worldwide, both for human and animal health. In the animal health sector actions have been taken as concerns grow regarding the development and spread of antimicrobial resistance. Mastitis is the most common infection in dairy cattle. We aimed to summarize the genetic determinants found in staphylococci, streptococci, and Enterobacteriaceae isolated from mastitic milk samples and provide a comparison of percentage resistance to a variety of antimicrobials in European countries.     

徐州市市售生肉中单核细胞增生李斯特菌污染及其分子特征分析

目的 分析2018年和2020年徐州市市售生肉中单核细胞增生李斯特菌检出率及其分子生物学特征。方法 随机采集市区零售鲜或冷冻生禽肉及调理肉，按照GB 4789.30—2016《食品安全国家标准 食品微生物学检验 单核细胞增生李斯特氏菌检验》对单核细胞增生李斯特菌进行分离、鉴定，并分析其血清型、耐药性、毒力基因型、脉冲场凝胶电泳（PFGE）分子分型。结果 142份市售生肉中有40份检出单核细胞增生李斯特菌，检出率为28.2%（40/142）；血清型主要为1/2a型，占50.0%（20/40）；40株单核细胞增生李斯特菌共分为15种PT型；对氨苄西林及青霉素耐药菌株分别有4株和2株；所有菌株均携带多种毒力基因。结论 徐州市市售生肉中单核细胞增生李斯特菌污染较严重，存在小规模同源菌株，需进一步加强监测管理，以防食源性疾病的发生。     

Identification of genomic regions associated with total and progressive sperm motility in Italian Holstein bulls

Sperm motility is directly related to the ability of sperm to move through the female reproductive tract to reach the ovum. Sperm motility is a complex trait that is influenced by environmental and genetic factors and is associated with male fertility, oocyte penetration rate, and reproductive success of cattle. In this study we carried out a GWAS in Italian Holstein bulls to identify candidate regions and genes associated with variations in progressive and total motility (PM and TM, respectively). After quality control, the final data set consisted of 5,960 records from 949 bulls having semen collected in 10 artificial insemination stations and genotyped at 412,737 SNPs (call rate >95%; minor allele frequency >5%). (Co)variance components were estimated using single trait mixed models, and associations between SNPs and phenotypes were assessed using a genomic BLUP approach. Ten windows that explained the greatest percentage of genetic variance were located on Bos taurus autosomes 1, 2, 4, 6, 7, 23, and 26 for TM and Bos taurus autosomes 1, 2, 4, 6, 8, 16, 23, and 26 for PM. A total of 150 genes for TM and 72 genes for PM were identified within these genomic regions. Gene Ontology enrichment analyses identified significant Gene Ontology terms involved with energy homeostasis, membrane functions, sperm-egg interactions, protection against oxidative stress, olfactory receptors, and immune system. There was significant enrichment of quantitative trait loci for fertility, calving ease, immune response, feed intake, and carcass weight within the candidate windows. These results contribute to understanding the architecture of the genetic control of sperm motility and may aid in the development of strategies to identify subfertile bulls and improve reproductive success.