Research On Rapid Reporting Procedures For Positive Culture Of Blood And Sterile Fluid

Objectives To reseach the application of matrix assisted laser desorption ionization timeof-flight mass spectrometry(MALDI-TOF MS)combined with VITEK2 automatic microbial identification instrument(VITEK2)in rapid identification of blood and body liquid and antimicrobial sensitivity test(AST).To establish a suitable rapid reporting procedure for positive samples of blood culture and aseptic body liquid.The selection of antibiotics for clinicians provided a reliable basis quickly and accurately,which can greatly reduce the death rate of patients and shorten the length of hospital stay.Methods Three hundred cases of blood culture positive bottles were selected from the laboratory bacteria room of Tangshan Gongren Hospital from February 2019 to February2020.The positive bottles were smeared and examined by gram staining.Then transferred to an appropriate solid medium according to the results of microscopic examination.The bacteria membrane was grown in the culture at 37 ? for 4 hours.After 18~24h,rapid identification and antimicrobial susceptibility testing were performed with pure colonies by MALDI-TOF MS and VITEK2.Results 1 Three hundred cases of single bacterial infection were collected,including 146 cases of Enterobacterium,34 cases of non-fermentative,67 cases of Staphylococcus,27 cases of Enterococcus,16 cases of Streptococcus,and 10 cases of rare bacterial;2 With the results of colony identification by MALDI-TOF MS as the final result,the bacterial membrane results of 181 gram-negative strains showed that 181(100%)strains was identified to the genus level and 174(96%)strains was identified to the species level by MALDI-TOF MS.VITEK2 could identify 174(96%)strains to the species level;The bacterial membrane results of 101 strains gram-positive showed that MALDI-TOF MS could identify 100(99%)strains to the genus level and 96(95%)strains to the species level,and VITEK2 could identify 92(91%)strains to the species leve.The coincidence rate between membranes and colony was compared who was identified by MALDI-TOF MS,and the difference has not statistically significant(P>0.05).The coincidence rate of membranes between MALDI-TOF MS and VITEK2 was compared,the difference has statistically significant(P<0.05);The identification coincidence rate between VITEK2 of bacterial membrane and VITEK2 of colony were compared,and the difference has no statistically significant(P>0.05).There was 18 strains bacterial with no membranes,which could not be identified.But they only accounted for 6% of all samples and most of them were gram-positive streptococcus and gram-positive bacilli.3 VITEK2 was used to identify 263 common bacteria for AST of bacterial membrane and colony.For 170 strains of gram-negative bacilli,compared with AST of bacterial membrane and AST of routine colony,the total compliance rate was 98%(2175/2215).There were 94 strains of grampositive bacteria,compared with AST of bacterial membrane and AST of routine colony,the total compliance rate was 99%(1337/1355).When the results were inconsistent of two method,e-test method was used as the gold standard and to compare the result of two method.There was no statistically significant difference between gram-negative bacilli and gram-positive cocci(P>0.05).4 The time was(14.48±1.94)h of MALDI-TOF MS combined with VITEK2 rapid identification and AST.The time of traditional process was(32.92±3.32)h.The difference was statistically significant(P<0.05).Conclusions 1 MALDI-TOF MS can be used for rapid identification of blood and sterile fluid culture with bacterial membrane.Meanwhile,the identification of VITEK2 with membrane in a laboratory without MALDI-TOF MS could also be used for rapid identification of blood and sterile fluid culture.2 AST of VITEK2 with bacterial membrane could be used for rapid AST of blood and sterile fluid.3 MALDI-TOF MS combined with VITEK2 could be applied to the rapid identification of blood and sterile body fluids,and the TAT was significantly reduced.So it was a fast,accurate and effective method,and it was suitable for the promotion and application in clinical microbiological testing.Figure3;Table10;Reference 110...