Comparison of commonly used antimicrobial susceptibility testing methods for evaluating susceptibilities of clinical isolates of Enterobacteriaceae and nonfermentative Gram-negative bacilli to cefoperazone-sulbactam

Shio Shin Jean, Chun Hsing Liao, Wang Huei Sheng, Wen Sen Lee, Po Ren Hsueh

研究成果: 雜誌貢獻文章

6 引文 斯高帕斯(Scopus)


Background/Purpose: The aim of this study was to investigate the cefoperazone-sulbactam (CFP-SUL) susceptibilities of important Gram-negative bacteria (GNB) by agar dilution (reference method), disk diffusion, and two automated methods. Methods: A total of 799 GNB isolates, including. Enterobacteriaceae (n = 500) and nonfermentative GNB (NFGNB,. n = 299), were recovered from various clinical specimens collected at National Taiwan University Hospital, Taipei, Taiwan from November 2013 to December 2014. The agar dilution method, disk diffusion method, and two automated susceptibility systems (Phoenix and Vitek 2) were used for testing susceptibility of the isolates to CFP-SUL. Categories of susceptibility (susceptible, intermediate, or resistant) to CFP-SUL yielded from each method were interpreted according to CFP-SUL interpretive breakpoints proposed previously. The results of categorical agreement and errors obtained between the agar dilution method and the other three methods were analyzed. Results: The Vitek 2 system had the highest error rates against. Escherichia coli (n = 150) and. Enterobacter cloacae (n = 77) isolates, i.e., 6.7% and 11.7% minor errors, 8.5% and 1.7% major errors, and 40% and 20% very major errors, respectively. Additionally, the Vitek 2 system was also found to have a significantly lower sensitivity (44.4%) and lower positive predictive value (18.2%) for detecting CFP-SUL nonsusceptible. E. coli isolates than other methods. For carbapenem-nonsusceptible. Enterobacteriaceae isolates, the Vitek 2 system failed to detect correct susceptibility to CFP-SUL. The three methods failed to correctly detect CFP-SUL susceptibility categories against all NFGNB isolates except. Pseudomonas aeruginosa + Conclusion: The Vitek 2 system is a suboptimal method in correctly detecting CFP-SUL susceptibility categories for. E. coli,. E. cloacae, and carbapenem-nonsusceptible. Enterobacteriaceae isolates.
頁(從 - 到)454-463
期刊Journal of Microbiology, Immunology and Infection
出版狀態已發佈 - 八月 2017


ASJC Scopus subject areas

  • Microbiology (medical)
  • Immunology and Allergy
  • Immunology and Microbiology(all)
  • Infectious Diseases