Evaluation of Antimicrobial Susceptibility Testing Performance of DL 96 System for Enterobacterales

Hua Wu,1 Xiaojun Zhou,1 Fan Zhou,2 Dongliang Huang,3 Tao Huang1 1Department of Laboratory Medicine, Hainan General Hospital, Affiliated Hainan Hospital of Hainan Medical College, Haikou, People’s Republic of China; 2International School of Public Health and One Health, Hainan Medical University, Haikou, People’s Republic of China; 3Emergency Department, Armed Police Hospital of Hainan, Haikou, People’s Republic of ChinaCorrespondence: Tao Huang, Department of Laboratory Medicine, Hainan General Hospital, Affiliated Hainan Hospital of Hainan Medical College, No. 19, Xiuhua Road, Xiuying District, Haikou, 570311, People’s Republic of China, Tel +868986842560, Email 13005080993@163.comAbstract: DL96 Microbial Identification/Antimicrobial Susceptibility Testing (ID/AST) System (Zhuhai DL, Guangdong, China) is one of the most commonly used commercial ID/AST System in China. This study aims to evaluate the performance of DL 96E for Antimicrobial Susceptibility Testing (AST) of 270 Enterobacterales isolates from Hainan general hospital using the broth microdilution method (BMD) as reference method. CLSI M52 criteria was followed when analyzing the evaluation results. Twenty antimicrobial agents were evaluated, and categorical agreement (CA) ranged from 62.8% to 96.5%. Imipenem had the lowest CA (63.9%) and highest very major errors (VME) (52.8%). A total of 103 carbapenem-resistant Enterobacterales were evaluated; DL 96E miss identified 22 isolates, including six carbapenemase-producing Enterobacteriaceae. DL 96E must adjust the Minimum Inhibitory Concentration (MIC) ranges of ciprofloxacin, levofloxacin, and piperacillin-tazobactam to cover Clinical and Laboratory Standards Institute (CLSI) breakpoints, adjust the formulation of some antimicrobial, such as imipenem, and increase the MIC detection range to cover the Quality control (QC) strains’ MIC range.Keywords: antimicrobial susceptibility testing, broth microdilution method, minimum inhibitory concentration, categorical agreement