Rapid identification of gram-negative bacteria and corresponding resistance determinants from blood cultures by BC-GN assay / 中华微生物学和免疫学杂志

ABSTRACT

Objective To evaluate the performance and clinical utility of Verigene gram-negative blood culture ( BC-GN ) assay for a rapid identification of gram-negative bacteria and resistance genes . Methods Non-repetitive blood culture samples containing gram-negative bacteria were collected from inpa-tients in the Second Affiliated Hospital of Zhejiang University School of Medicine from June to October , 2013 .BC-GN assay was performed to identify the species and genetic resistance determinants of gram -nega-tive bacteria directly from the positive blood culture bottles .VITEK MS and the VITEK 2 Compact were used for species identification and antimicrobial susceptibility test , the results of which were considered as gold standards.The resistance genes were further validated by PCR amplification and sequencing analysis .A comparison of the results and time between the BC-GN assay and routine methods was conducted . Results The detection range of BC-GN assay almost covered all of the common gram-negative bacteria .BC-GN assay showed an advantage of high accuracy in the identification of Escherichia coli (13/13), Klebsiella pneumoniae (19/24), Klebsiella oxytoca (9/9), Pseudomonas aeruginosa (39/39), Serratia marcescens (4/5), Enterobacter spp.(6/8), Citrobacter spp.(11/11), Proteus spp.(6/6) and Acinetobacter spp. (24/24) with an overall accuracy of 94.24%for the identification of mono-microbial blood culture samples . Moreover , BC-GN assay accurately identified all of the bacteria and resistance genes from the two multi -mi-crobial samples .Species identification and resistance profiles could be 42 hours earlier available by using BC-GN assay than those by using routine methods .Conclusion BC-GN assay could simultaneously and ac-curately identify bacteria and resistance determinants from blood cultures within 2 hours.More time for clini-cally effective therapy could be achieved by using BC-GN assay for the reduction of mortality associated with bloodstream infection .