Homology Analysis Of 15 Strains Of Burkholderia Cepacia From Bloodstream Infection

Objectives To carry out homology analysis and drug resistance of 15 strains of Burkholderia cepacia from blood infections, discovered from May 22, 2013 to June 27, so as to better control the nosocomial infections caused by Burkholderia cepacia in a short time and find possible causes of bloodstream infections, and to provide the basis for clinical treatment of infections.Methods Analyze the infection features and drug resistance of 15 strains of Burkholderia cepacia cultured and identified by Bactec9120 automated blood culture system and Phoenix-100 automatic microorganism analyzer from May 22 2013 to June 27 2013.According to the results of drug sensitivity, carry out different resistance spectrum analysis;meanwhile, apply the new molecular biology typing method- the multilocus sequence typing method(MLST) to amplify atp D, glt B, gyr B, rec A, lep A, pha C and trp B housekeeping gene fragments by PCR. The sequencing results are compared with the MLST database to obtain the housekeeping gene numbers and sequence types. Thus classify the 15 strains of Burkholderia cepacia from blood infections quickly and analyze their homology.Results 1 Clinical data analysis: the 15 strains of Burkholderia cepacia came from the three departments. Thirteen strains were from Department of Neurosurgery, and the other two strains were from the Internal Hematology and the Intensive Care Unit. The patients received invasive procedures or had indwelling catheter inserted and stayed in the ICU for observation. The patients ranged in age from 25 to 88 years old. Eleven of them were male and 4 were female. All patients had the clinical manifestations of bloodstream infection. 2 Analysis of antimicrobial resistance: the study of medicine sensitivity results showed that Burkholderia cepacia was resistant to Amoxicillin/clavulanic, Aztreonam, Cefotaxime, Cefepime, Tetracycline; but it was sensitive to Ceftazidime, Meropenem, Trimethoprim-sulfamethoxazole, Piperacillin/tazobactam;the antibiotic susceptibility spectrum was divided into five types by the small difference in resistance among Chloramphenicol, Levofloxacin, Moxifloxacin, Piperacillin, there are 7 strains of drug resistance spectrum which is the chloramphenicol-intermediary,levofloxacin and moxifloxacin-sensitive, piperacillin-resistant strains. 3 Multilocus sequence typing: the sequencing results of 15 strains were spliced to get the complete sequence, compared with MLST database data to obtain the allele numbers and ST.The 7 housekeeping genes in thirteen of fifteen strains were the same. Meanwhile gyr B housekeeping gene had a new sequence type as a new ST. The 15 strains of Burkholderia cepacia were divided into 3 genotypes, ST482, ST608 and a new ST sequence. The 13 strains from the same department had same ST.Conclusions 1 he bloodstream infection caused by Burkholderia cepacia in a short time was outbreak of nosocomial infection. The 13 strains from Department of Neurosurgery belonged to the same strain. 2 In the outbreak of nosocomial infection,epidemic strains were the chloramphenicol intermediary, levofloxacin and moxifloxacin sensitive, piperacillin-resistant strains. 3 According to the result of MLST method, the type ST of the 13 strains found in Department of Neurosurgery not only was the same but also was a new type ST, different from those from the other two departments. The MLST applied showed a high resolution, so it was crucial in the investigation of the nosocomial blood infection outbreak caused by Burkholderia cepacia.