Klebsiella Pneumoniae Biofilm And Capsular Formation Analysis Related To Virulence Genes

Objective:Klebsiella pneumoniae was originally named as Friedland bacillus,which changed its name to klebsiella in 1886.It is common in the opportunistic pathogens of hospital infection.It can not only colonize human gastrointestinal tract,skin and nasopharynx,but also cause urinary tract and biliary tract infection,osteomyelitis and bacteremia,which will cause serious consequences.In addition,klebsiella pneumoniae has a strong ability to form capsule and biofilm,which can carry many virulence factors that can cause multiple drug resistance and severe infection in clinic.Klebsiella pneumoniae strains are acquiring antibiotic resistance with increasing frequency at the level of nosocomial infection,which has caused the global spread of this multidrug-resistant pathogen.Therefore,the correlation between the formation of capsule and biofilm and the virulence gene of bacterial isolates,as well as the clinical prevalence,is of great importance to the clinical anti-infection treatment.This study collected klebsiella pneumoniae infection patient specimens from the first affiliated hospital of Dalian medical university between January 2014 and October 2018,features of infection in patients with my area to detect all strains capsule and biofilm carrying rate,clinical isolates were serotype with PCR and virulence gene detection,the capsule and biofilm formation ability and detecting the virulence genes of correlation analysis,analysis of the formation of klebsiella pneumoniae capsular strain resistance and biological membrane,in order to understand the formation of the capsule and biofilm of klebsiella pneumoniae in Dalian region and its correlation with the prevalence of common virulence genes,further explore the complex drug resistance of clinical klebsiella pneumoniae anti-infection treatment.Methods:We analyzed the clinical infection characteristics of 110 strains of klebsiella pneumoniae isolates screened out,then tested the carrying rates of all strains’ capsulesand biofilms,extracted genomic DNA of the strains,and finally performed serotype detection and virulence gene screening through PCR technology.After that,the correlation between the ability of capsule and biofilm formation and virulence genes was analyzed to determine whether the drug sensitivity of klebsiella pneumoniae changed after the formation of capsule or biofilm.Results:Blood samples were at most,about 70%.Distribution of clinical departments in the emergency ward was the highest detection rate,at 23.64%.The capsule positive rate and biofilm positive rate of 110 strains klebsiella pneumoniae were 45% and 58.18%respectively.For PCR detection results,110 strains of bacteria in most serotype K1,at35.45%,serotype K2,accounting for 19.09% of the total,the next was followed by K57,K20 and K54 accounted for 4.55%,2.73% and 0.91% respectively,11 kinds of virulence genes have been carrying phenomenon,to some extent fimH and wabG virulence factor detection rate were higher in the biofilm positive strains accounted for 94.12% and85.29% respectively.The biofilm-positive strains were more resistant to ampicillin and gentamicin than the biofilm-negative strains.Conclusions:Klebsiella pneumoniae had a strong ability to form capsule and biofilm,and the positive rate of biofilm had been rising year by year.Two kinds of serum virulence genes,K1 and K2,accounted for a relatively high proportion and were widely prevalent.At the same time,the virulence gene rmpA had a high carrying rate,which proved that rmpA virulence gene was also related to the formation of bacterial pod,and K20 and K54 were detected to have 3 and 1 strains respectively.In the rare,there are reports of K20 had the ability of forming biofilm and capsule,which need to be paid attention to in the future.11 virulence genes in 110 strains of klebsiella pneumoniae all showed different degrees of carrying phenomenon,so it was speculated that the formation of biofilm capsule and biofilm might be related to the distribution of virulence factors.Biofilm can prevent drug penetration and lead to ampicillin resistance,and due to the abuse of antibacterial drugs,the positive rate of biofilm increases,and the drugresistance may become stronger and stronger.Virulence genes fimH and wabG were highly carried in the strains with positive biofilm.The formation of biofilm had a great influence on virulence and drug resistance of the strains,and the virulence should be paid attention to.This study revealed the positive distribution and epidemic trend of klebsiella pneumoniae capsule and biofilm in Dalian region,and analyzed its correlation with virulence genes and drug resistance,so as to provide theoretical basis for its classification and correct treatment.