Establishment And Evaluation Of Diversilab System Typing Methods In Acinetobacter Baumannii

ObjectiveTo apply the DiversiLab system for genotyping of Acinetobacter baumannii and evaluate the discriminatory power and concordance among DiversiLab system, multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE).MethodsEighty-night non-duplicated clinical Acinetobacter baumannii isolated from multiple cities of China were typed by DiversiLab system. The results were compared with those of pulsed-field gel electrophoresis and multilocus sequence typing. Simpson's index of diversity and confidence interval was used to compare discriminatory power among DiversiLab system, PFGE and MLST, while Adjusted rand index and Wallace coefficient for concordance evaluation.Results89 Acinetobacter baumannii isolates were differentiated into 8 clusters and 28 unique types by DiversiLab system. MLST identified 39 distinct sequence types, which fell into one clone complex CC92 and 47 singletons, while PFGE resolved 5 pulsotypes and 37 unique types. Simpson's diversity indices and confidence interval were 0.899(0.859-0.939),0.894(0.847-0.94) and 0.934(0.909-0.959) for DiversiLab system, MLST and PFGE respectively. Adjusted Rand index among three typing method was AR(MLST-PFGE)=0.502, AR(DiversiLab-PFGE)=0.479, AR(DiversiLab-MLST)=0.434 respectively. It indicated that PFGE and MLST have the highest congruence among the three methods. Compared with MLST, Diversilab system was better congruence with PFGE. For Wallace coefficient, W1 (PFGE-MLST)=0.709, W1 (PFGE-DiversiLab)=0.659. PFGE results could predict generally the typing results of MLST and DiversiLab system.ConclusionsAmong the three molecular typing methods in Acinetobacter baumannii, DiversiLab system was fast, simple, reproducible and highly discriminatory power, better congruence with PFGE compared with MLST, so could be used as a first-line typing tool for rapid epidemiological investigation of a large number of isolates.