Abstract：
Escherichia coli is one of the major pathogens causing mastitis that adversely affects the dairy industry worldwide. This study employed whole genome sequence (WGS) approach to characterize the repertoire of antibiotic resistance genes (resistome), virulence genes (virulome), phylogenetic relationship and genome wide comparison of a multi drug resistant (MDR) E. coli(SCM-21) isolated from a case of subclinical bovine mastitis in Bangalore, India. The genome of E. coli SCM- 21 was found to be of 4.29 Mb size with 50.6% GC content, comprising a resistome of 22 genes encoding beta-lactamases (blaTEM,blaAmpC), polymyxin resistance (arnA) and various efflux pumps (acr, ade, emr,rob, mac, mar, rob), attributing to the bacteria\'s overall antibiotic resistance genetic profile. The virulome of E. coli SCM-21 consisted of genes encoding different traits [adhesion (ecp, fim, fde), biofilm formation (csg) and toxin production (ent, esp, fep, gsp)], necessary for manifestation of the infection. Phylogenetic relationship of E. coli SCM- 21 with other global E. coli strains (n = 4867) revealed its close genetic relatedness with E. coli strains originating from different hosts of varied geographical regions [human (Germany) bos taurus (USA, Belgium and Scotland) and chicken (China)]. Further, genome wide comparative analysis with E. coli (n = 6) from human and other animal origins showed synteny across the genomes. Overall findings of this study provided a comprehensive insight of the hidden genetic determinants/power of E. coli SCM-21 that might be responsible for manifestation of mastitis and failure of antibiotic treatment. Aforesaid strain forms a reservoir of antibiotic resistance genes (ARGs) and can integrate to one health micro biosphere.
摘要：
大肠杆菌是引起乳腺炎的主要病原体之一，对全球乳制品行业产生不利影响。本研究采用全基因组序列（WGS）方法来表征抗生素抗性基因（抗性组），毒力基因（病毒组），从班加罗尔的亚临床牛乳腺炎病例中分离出的多药耐药（MDR）大肠杆菌（SCM-21）的系统发育关系和全基因组比较，印度。大肠杆菌SCM-21的基因组大小为4.29Mb，GC含量为50.6%，包含22个编码β-内酰胺酶的基因的抗性组(blaTEM，blaAmpC)，多粘菌素抗性(ARNA)和各种外排泵(ACR，ade,emr,Rob,mac,mar,rob),归因于细菌的总体抗生素抗性遗传特征。大肠杆菌SCM-21的病毒组由编码不同性状的基因组成[粘附(ecp，FIM,fde),生物膜形成(csg)和毒素产生(ent，esp,fep,gsp)]，表现为感染所必需的。大肠杆菌SCM-21与其他全球大肠杆菌菌株的系统发育关系（n=4867）揭示了其与源自不同地理区域的不同宿主的大肠杆菌菌株的紧密遗传相关性[人类（德国）bostaurus（美国，比利时和苏格兰)和鸡肉(中国)]。Further,与人类和其他动物来源的大肠杆菌（n=6）的全基因组比较分析显示，整个基因组具有同质性。这项研究的总体发现提供了对大肠杆菌SCM-21的隐藏遗传决定子/功效的全面了解，这些遗传决定子/功效可能是乳腺炎的表现和抗生素治疗失败的原因。上述菌株形成了抗生素抗性基因（ARG）的库，可以整合到一个健康的微生物圈中。
