| Proteus mirabilis is an important zoonotic pathogen and has been considered as a zoonotic bacterium in the human medicine clinics,which is found in abundance second to intestinal pathogenic Escherichia coli and every year causing severe the morbidity and mortality.The increasing trend has attracted the attention of scholars at the country and abroad,because of producing various diseases such as diarrhea,kidney stones,conjunctivitis and Crohn's disease.Clinically,antibiotics are usually used to treat diseases caused by the bacteria.However,due to the long-term unreasonable use of antibiotics,the production of highly resistant strains of Proteus mirabilis has been promoted,which not only increases the difficulty in the treatment of diseases caused by the bacteria,but also endures them.The spread of drug genes and mobile primitives between bacteria poses a serious threat to the public health security of humans and animals.Therefore,it is urgent to develop a drug resistance gene environment for highly resistant and pathogenic Myxoproteobacteria,in order to provide scientific basis and theoretical basis for the study of its resistance mechanism.This study was intended to isolate and identify canine diarrhea samples from suspected bacterial enteritis occurred in Changchun from 2015 to 2017,screen for Proteus mirabilis and sequence and analyze the genome and plasmid of multi-drug resistant pathogenic strains.It lays a foundation for the study of the resistance mechanism of Proteus mirabilis.The main research contents were as follows:1.Isolation,identification and biological characteristics analysis of Proteus mirabilisTwelve strains of Proteus mirabilis were isolated from 62 samples of canine diarrhea.The isolates were highly resistant to veterinary clinics rarther few strains were sensitive to ciprofloxacin,enrofloxacin and ceftriaxone.Among them,the isolate CC15031 strain was not only resistant to sulfamonomethoxine,florfenicol,doxycycline,ceftriaxone,clindamycin,ciprofloxacin,enrofloxacin,erythromycin,chloramphenicol,Qing Ten antibiotics such as tylosin were all resistant,and their pathogenicity was also strong(LD50=2.8×106 cfu/mL).2.Whole genome sequencing s analysis of Multidrug-resistant Pathogenic StrainsIn this study,genome-wide sequencing analysis of the Proteus mirabilis CC15031 strain with high pathogenicity and drug resistance were carried out by second-generation sequencing-three-generation sequencing method.CC15031 was 4,031,742 bp in length and GC content.38.99%,a total of 3745 genes,carrying 18 resistance genes on the genome(can directly mediate resistance to penicillins,cephalosporins,macrolides,aminoglycosides,tetracyclines,sulfonamides)At the same time,the strain also carries 15 gene islands(where the gene island GIs012 carries 8 drug resistance genes),6 T3 SS secretion systems,and non-coding region sequences of unknown function.In addition,the genome of the bacterium contains 363 virulence factors including hemolysin Hyla and pili operon mrp J.3.Preliminary study on plasmid sequence analysis and function of Multidrug-resistant Pathogenic StrainsIn this study,plasmid sequence analysis of pathogenic bacteria CC15031 with multi-drug resistance.The full-length plasmid was 261,999 bp and the GC-content was 49.9% containing 509 genes,seven tRNAs and one rRNA,including blaCTX-M,blaTEM-1,mphA,tetC,sul2,ermB,macB,vanSb and other seventeen drug resistance genes(which can mediate antibiotic resistance to cephalosporins,sulfonamides,vancomycin,etc.).The plasmid was subjected to onjugative transfer assay,and transferred to the recipient bacteria at 4 h,and the zygote was exposed to cefuroxime,cefepime,chloramphenicol,sulfamonomethoxine,erythromycin,clindamycin.Nine antibiotics such as cytokines,doxycycline,clindamycin and gentamicin produce resistance. |
PDF Full Text Request