Acta Scientific Microbiology (ASMI) (ISSN: 2581-3226)

Research Article Volume 4 Issue 1

Impact of Susceptible-Dose-Dependent (SDD) Minimum Inhibitory Concentration (MIC) on Reporting and Prescribing Antibiotics

Kalpana T1, Mugunthan M2, Symphonia A1, Haritha M2, Deepashree R3 and Apurba Sastry4*

1Junior Resident, Department of Microbiology, JIPMER, Pondicherry, India
2Senior Resident, Department of Microbiology, JIPMER, Pondicherry, India
3Assistant Professor, Department of Microbiology, JSS Medical College, Mysore, India
4Associate Professor, Department of Microbiology, JIPMER, Pondicherry, India

*Corresponding Author: Apurba Sastry, Associate Professor, Department of Microbiology, JIPMER, Pondicherry, India.

Received: September 07, 2020; Published: December 09, 2020



Introduction: Clinical and Laboratory Standards Institute (CLSI) introduced susceptible dose dependent (SDD) in place of intermediate category for selected drug pathogen combinations such as Enterobacteriaceae-cefepime and Enterococcus-daptomycin. For SDD-isolates, the antimicrobial agent can be used in higher-than-normal doses, precluding the use of higher antimicrobials thereby preventing antibiotic resistance. Therefore, this study was undertaken.

Aim of the Study: To know the SDD pattern among Enterobacteriaceae and Enterococcus to cefepime and daptomycin respectively.

Settings and Design: The Enterobacteriaceae and Enterococcus isolates from blood cultures were included in this study between August 2019 to July 2020.

Materials and Methods: After excluding the repeat isolates, antimicrobial susceptibility test was carried out by VITEK 2 system (bioMérieux) and the MIC result obtained was interpreted by using CLSI guideline 2019. The Enterobacteriaceae and Enterococcus isolates showing SDD results for cefepime and daptomycin respectively were determined.

Statistical Analysis Used: Nil.

Results: Total of 545 Enterobacteriaceae and 115 Enterococcus isolates were included in the study. 15.1% of Enterobacteriaceae isolates were SDD to cefepime, majority of which were Escherichia coli and Klebsiella spp. Among the SDD-isolates, 36.6% were found to have MIC of 4 µg/mL and 63.4% exhibited a MIC of 8 µg/mL. Cefepime in increased dose is a better therapeutic option for the SDD isolates rather switching to higher antimicrobials like carbapenems. Among the Enterococcus isolates, 28.7% (all were E. faecalis) were found SDD to daptomycin.

Conclusion: We found there was an increase in isolation of Enterobacteriaceae and Enterococcus isolates that were SDD to cefepime and daptomycin respectively.

Keywords: SDD; MIC; Cefipime; Daptomycin; Enterobacteriaceae; Enterococcus



  1. Lorian V. “Antibiotics in laboratory medicine”. Lippincott Williams and Wilkins (2005).
  2. Nielsen LE., et al. “One Size Fits All? Application of Susceptible-Dose-Dependent Breakpoints to Pediatric Patients and Laboratory Reporting”. Journal of Clinical Microbiology1 (2019).
  3. Heil EL and Johnson JK. “Commentary: Impact of CLSI Breakpoint Changes on Microbiology Laboratories and Antimicrobial Stewardship Programs”. Journal of Clinical Microbiology4 (2016): 840-844.
  4. Abbey TC and Deak, E. “What’s New from the CLSI Subcommittee on Antimicrobial Susceptibility Testing M100, 29th Edition”. Clinical Microbiology Newsletter 41 (2019): 203-209.
  5. Nguyen HM., et al. “Determining a clinical framework for use of cefepime and β-lactam/β-lactamase inhibitors in the treatment of infections caused by extended-spectrum-β-lactamase-producing Enterobacteriaceae”. Journal of Antimicrobial Chemotherapy4 (2014): 871-880.
  6. Endimiani A., et al. “Cefepime: a reappraisal in an era of increasing antimicrobial resistance”. Expert Review of Anti-Infective Therapy6 (2008): 805-824.
  7. Foong KS., et al. “Clinical impact of revised cefepime breakpoint in patients with Enterobacteriaceae bacteremia”. In Open Forum Infectious Diseases8 (2019): ofz341.
  8. Rivera CG., et al. “Impact of cefepime susceptible-dose-dependent MIC for Enterobacteriaceae on reporting and prescribing”. Antimicrobial Agents and Chemotherapy6 (2016): 3854-3855.
  9. Park KH., et al. “Impact of revised broad-spectrum cephalosporin Clinical and Laboratory Standards Institute breakpoints on susceptibility in Enterobacteriaceae producing AmpC β-lactamase”. Infection and Chemotherapy1 (2017): 62-67.
  10. Satlin MJ., et al. “Development of Daptomycin Susceptibility Breakpoints for Enterococcus faecium and Revision of the Breakpoints for other Enterococcal species by the Clinical and Laboratory Standards Institute”. Clinical Infectious Diseases6 (2020): 1240-1246.


Citation: Apurba Sastry., et al. “Impact of Susceptible-Dose-Dependent (SDD) Minimum Inhibitory Concentration (MIC) on Reporting and Prescribing Antibiotics". Acta Scientific Microbiology 4.1 (2020): 42-46.


Acceptance rate30%
Acceptance to publication20-30 days

Indexed In

News and Events

  • Certification for Review
    Acta Scientific certifies the Editors/reviewers for their review done towards the assigned articles of the respective journals.
  • Submission Timeline for Upcoming Issue
    The last date for submission of articles for regular Issues is July 10, 2024.
  • Publication Certificate
    Authors will be issued a "Publication Certificate" as a mark of appreciation for publishing their work.
  • Best Article of the Issue
    The Editors will elect one Best Article after each issue release. The authors of this article will be provided with a certificate of "Best Article of the Issue"
  • Welcoming Article Submission
    Acta Scientific delightfully welcomes active researchers for submission of articles towards the upcoming issue of respective journals.

Contact US