Using MALDI-TOF MS To Identify Clinically Uncommon Non-fermentative Bacteria And Their Drug Susceptibility Analysis

Objective: To evaluate the application value of MALDI-TOF MS technique in the rapid identification of clinically uncommon non-fermentative bacteria.Methods: From July 2013 to October 2016,65 clinical isolates of clinically uncommon non-fermentative bacteria were collected from the First Affiliated Hospital of Anhui Medical University,including 21 strains of sputum,13 strains of urine,9strains of blood,9 strains of bone marrow,8 strains of secretions,2 strains of drain fluid,1 strain of cerebrospinal fluid,1 strain of bile,3 strains of other body fluids.The accuracy of the identification system of MALDI-TOF MS and Vitek2 Compact was compared and all the results were confirmed by 16 Sr RNA sequence analysis.Results:Of 65 strains,MALDI-TOF MS identified 64 strains(98.5%)to the species level and 1 strains(1.5%)to the genus level;Vitek2 Compact identified 58 strains(89.2%)to the species level and 7 strains(10.8%)were failed to identify.All strains were successfully amplified 16 Sr RNA gene fragment and were identified to the species level by 16 Sr RNA sequence analysis.According to 16 Sr RNA sequence analysis,MALDI-TOF MS and Vitek2 Compact correctly identified 98.5%(64/65)and 89.2%(58/65)strains to the species level,which has obvious statistical significance(?2=4.17,P<0.05).Conclusion:Compared to Vitek2 Compact system,MALDI-TOF MS could correctly identify more clinically uncommon non-fermentative bacteria to the species level and it can be used as one of the routine method for those groups of bacteria in clinical microbiology laboratory.Objective: To know the antibiotics sensitivity patterns of 64 strains of clinically uncommon non-fermentative bacteria.Methods: Except for one Moraxella osloensis,other 64 strains were performed for the antibiotics susceptibility tests by VITEK2 COMPACT system with Kirby-Bauer method for supplemen(CLSI 2015).The data were analyzed by WHONET 5.6 software.Results : All strains had relatively high sensitivity to cefoperazone/sulbactam,Piperacillin/Tazobactam,levofloxacin.Their resistance rates were 23.4%,26.6% and31.2% respectively.While these strains had high resistance to aztreonam and cefazolin,which resistance rates were 79.7% and 95.3%,respectively.For other 13 kinds of antibiotics,resistance rates were all above 40%.27 strains of Achromobacter xylosoxidans had low resistant rates to Piperacillin/Tazobactam and cefoperazone/ sulbactam,which were 22.2% and 25.9%,respectively.But their resistant rates to cefazolin,aztreonam,ceftriaxone and macrodantin were more than 90% and for the other 12 kinds of antibiotics the resistance rates were about 50%.Conclusion:64 strains of clinically uncommon non-fermentative bacteria had relatively low resistance rates to Piperacillin/Tazobactam and cefoperazone/ sulbactam but were more resistant to other tested antibiotics.Medical workers should rational use antibiotics for treatment by applying to the results of drug sensitive experiment,which are essential to control of the development and spread of drug-resistant strains.