| Klebsiella pneumoniae is an important zoonotic pathogen.After cattle infection,it can cause mastitis,enteritis and respiratory disease syndrome,which will bring certain economic losses to the cattle industry.In order to investigate the infection of Klebsiella pneumoniae in calves in Xinjiang and its drug resistance characteristics,this study collected nasal and anal swabs from 14 intensive cattle farms in Xinjiang from March 2020 to December 2020,and the specific gene khe of Klebsiella pneumoniae was amplified by PCR,and the molecular epidemiology of Klebsiella pneumoniae was investigated,and the positive samples were isolated and cultured to obtain Klebsiella pneumoniae strains;the isolates were identified by PCR and whole genome sequencing to determine their serotype and ST typing,PCR method was used to detect and analyze the carrying distribution of 16 virulence genes of Klebsiella pneumoniae;the micro broth dilution method was used to detect the sensitivity of isolates to 20 commonly used clinical antibiotics,and the carrying of 24 drug resistance genes was analyzed by PCR method.The results show that:1.Collected 495 nasal swab samples and 527 anal swab samples from calves in 14 intensive cattle farms in Xinjiang.PCR amplification was performed with Klebsiella pneumoniae khe gene primers,and 57 samples containing khe gene were detected in nasal swab samples,the detection rate was 11.52%(57/495),150 samples containing khe gene were detected in anal swabs,the detection rate was 28.46%(150/527);the positive samples containing khe gene were isolated and cultured by bacteria,and PCR identification of 16 S r RNA and khe gene,122 isolates of Klebsiella pneumoniae were obtained.2.53 isolates of Klebsiella pneumoniae were selected and used PCR method to identify the capsular serotype and virulence genes.The results showed that three capsular serotypes were detected in 5 isolates,2strains of K2 type,1 strain of K5 type,and 2 strains of K54 type.Among the isolates,11 virulence genes were detected among the 16 virulence genes of Klebsiella pneumoniae,namely wab G,uge,fim H,mrk D,ent B,ybt A,kfu,iut A,icu B,ure A,all S;40 isolates were identified by MLST,33 isolates of which were successfully compared to ST type,a total of 23 ST types were detected,and 7 were untyped.ST14 type,ST35 type and ST2140 type were superior ST type.3.Drug susceptibility test and drug resistance gene detection found that 40 isolates were all sensitive to carbapenems,aminoglycosides(amikacin),and polypeptide antibiotics,of which 33 strains showed different resistance to penicillin,cephalosporins,quinolones,aminoglycosides(kanamycin,gentamicin),tetracycline and sulfonamides,with resistance rates ranging from 5.00% to 60.00%.Multi-drug resistant strains accounted for 50.00% of the isolates.Among the 24 drug resistance genes,8 drug resistance genes were detected,including SHV,gyr A,par C,oqx A,oqx B,Sul 1,Sul 2,Acr AB.Among them,the detection rate of gyr A gene and Acr AB gene was the highest,which was 100.00%.Statistics found that the isolates carried at least two drug resistance genes.Conclusion: Klebsiella pneumoniae was detected in samples from the respiratory and digestive tracts of calves collected from intensive cattle farms in Xinjiang,and the detection rates were 11.52% and 28.46%.There were at least three capsular serotypes and 11 virulence genes in the isolates.23 ST types were identified by MLST,showing a high diversity of ST types.Drug susceptibility testing and drug resistance gene testing found that there are multiple drug resistance genes and multi-drug resistance in the intensive cattle farms sampled,suggesting that the ST type of Klebsiella pneumoniae prevalent in intensive cattle farms in Xinjiang is rich in diversity,strong drug resistance.This study provides a theoretical basis for the prevention and treatment of Klebsiella pneumonia in calves in Xinjiang. |
PDF Full Text Request