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

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)454-463
JournalJournal of Microbiology, Immunology and Infection
Volume50
Issue number4
DOIs
Publication statusPublished - Aug 2017

Fingerprint

Cefoperazone
Sulbactam
Enterobacteriaceae
Bacillus
Gram-Negative Bacteria
Agar
Enterobacter cloacae
Carbapenems
Escherichia coli
Taiwan
Pseudomonas aeruginosa

Keywords

  • Cefoperazone-sulbactam
  • Disk diffusion
  • Phoenix system
  • Susceptibility test
  • Vitek 2 system

ASJC Scopus subject areas

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

Cite this

@article{069f8cbb74dc479d8749bc0e16b45b85,
title = "Comparison of commonly used antimicrobial susceptibility testing methods for evaluating susceptibilities of clinical isolates of Enterobacteriaceae and nonfermentative Gram-negative bacilli to cefoperazone-sulbactam",
abstract = "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.",
keywords = "Cefoperazone-sulbactam, Disk diffusion, Phoenix system, Susceptibility test, Vitek 2 system",
author = "Jean, {Shio Shin} and Liao, {Chun Hsing} and Sheng, {Wang Huei} and Lee, {Wen Sen} and Hsueh, {Po Ren}",
year = "2017",
month = "8",
doi = "10.1016/j.jmii.2015.08.024",
language = "English",
volume = "50",
pages = "454--463",
journal = "Journal of Microbiology, Immunology and Infection",
issn = "0253-2662",
publisher = "Elsevier Taiwan LLC",
number = "4",

}

TY - JOUR

T1 - Comparison of commonly used antimicrobial susceptibility testing methods for evaluating susceptibilities of clinical isolates of Enterobacteriaceae and nonfermentative Gram-negative bacilli to cefoperazone-sulbactam

AU - Jean, Shio Shin

AU - Liao, Chun Hsing

AU - Sheng, Wang Huei

AU - Lee, Wen Sen

AU - Hsueh, Po Ren

PY - 2017/8

Y1 - 2017/8

N2 - 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.

AB - 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.

KW - Cefoperazone-sulbactam

KW - Disk diffusion

KW - Phoenix system

KW - Susceptibility test

KW - Vitek 2 system

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U2 - 10.1016/j.jmii.2015.08.024

DO - 10.1016/j.jmii.2015.08.024

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VL - 50

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EP - 463

JO - Journal of Microbiology, Immunology and Infection

JF - Journal of Microbiology, Immunology and Infection

SN - 0253-2662

IS - 4

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