Infection and Drug Resistance (Apr 2021)

Comparative Evaluation of Seven Tigecycline Susceptibility Testing Methods for Carbapenem-Resistant Enterobacteriaceae

  • Li H,
  • Zhou M,
  • Chen X,
  • Zhang Y,
  • Jian Z,
  • Yan Q,
  • Liu WE

Journal volume & issue
Vol. Volume 14
pp. 1511 – 1516

Abstract

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Hongling Li, Mao Zhou, Xia Chen, Yawen Zhang, Zijuan Jian, Qun Yan, Wen-En Liu Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, People’s Republic of ChinaCorrespondence: Wen-En LiuDepartment of Clinical Laboratory, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan 410008, People’s Republic of ChinaTel +86-731-84327440Fax +86-731-84327332Email [email protected]: Carbapenem-resistant Enterobacteriaceae (CRE) strains are extensively resistant to most antibiotics. Tigecycline is one of the few effective drugs that can be used to treat infections caused by CRE. The aim of this study was to evaluate the accuracy of different methods for detecting the susceptibility of CRE to tigecycline.Methods: Seven commonly used drug susceptibility testing methods were compared and evaluated for the ability to determine CRE tigecycline susceptibility: broth microdilution (BMD), agar dilution method (ADM), disk diffusion method, Etest, MicroScan, Vitek2 COMPACT, and BD Phoenix 100.Results: The minimum inhibitory concentration (MIC) of tigecycline to inhibit 50% and 90% of CRE growth (MIC50 and MIC90, respectively) assessed by ADM and BD Phoenix 100 was the same as that determined by the reference method, BMD. The MIC50 was 2 μg/mL, and the MIC90 was 4 μg/mL. The highest number of susceptible strains was detected by MicroScan, followed by BMD, Etest, ADM, BD Phoenix 100, Vitek2 COMPACT, and disk diffusion method, in descending order. No significant differences were observed among the tigecycline susceptibility results (P > 0.05) obtained from MicroScan, Etest, BD Phoenix 100, and BMD. BMD confirmed that 82.0% of strains were susceptible to tigecycline. ADM, MicroScan, and BD Phoenix 100 yielded the categorical agreement of 96%, 92%, and 93%, respectively. No method was found to present any very major errors (VMEs), and only the Vitek2 COMPACT yielded major errors (MEs) greater than 3%.Conclusion: Among the seven methods tested, the ADM, MicroScan, and BD Phoenix 100 methods were accurate for determining the tigecycline susceptibility of CRE. MicroScan was acceptable with better performance than other methods.Keywords: tigecycline, antibiotic susceptibility test, carbapenem-resistant Enterobacteriaceae, CRE

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