Skip to main content
SpringerLink
Log in

The Relationship Between Agar Thickness and Antimicrobial Susceptibility Testing

  • Short Communication
  • Published:
Indian Journal of Microbiology Aims and scope Submit manuscript

Abstract

Antimicrobial susceptibility testing can be done using solid or liquid-based medium. Solid-based assays are easy and inexpensive; they are limited by not being as quantitative as liquid-based assays. Agar depth can influence the accuracy of plate-based assays and it is assumed the basis of this effect is antimicrobial agent diffusion. We tested this assumption by using ETEST® to quantitate the relationship between agar depth and minimum inhibitory concentration and zone of inhibition.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1

References

  1. Piddock LJV (1990) Techniques used for the determination of antimicrobial resistance and sensitivity in bacteria. J Appl Bacteriol 68:307–318

    Article  CAS  PubMed  Google Scholar 

  2. Hudzicki J (2009) Kirby–Bauer disk diffusion susceptibility test protocol. http://www.microbelibrary.org/component/resource/laboratory-test/3189-kirby-bauer-disk-diffusion-susceptibility-test-protocol. Accessed 6 Aug 2017

  3. Clinical and Laboratory Standards Institute (2013) Performance standards for antimicrobial susceptibility testing; twenty-third informational supplement. Document M100-S23. CLSI, Wayne

    Google Scholar 

  4. Brennan-Krohn T, Smith K, Kirby J (2017) The poisoned well: enhancing the predictive value of antimicrobial susceptibility testing in the era of multidrug resistance. J Clin Microbiol 55:2304–2308. doi:10.1128/JCM.00511-17

    Article  PubMed  Google Scholar 

  5. Hombach M, Maurer F, Pfiffner T, Bottger E, Furrer R (2015) Standardization of operator-dependent variables affecting precision and accuracy of the disk diffusion method for antibiotic susceptibility testing. J Clin Microbiol 53:3864–3869. doi:10.1128/JCM.02351-15

    Article  PubMed  PubMed Central  Google Scholar 

  6. Cunningham D, Flournoy DJ (1983) The relationship of disc position to zone-of-inhibition size in the disc-agar diffusion test. Methods Find Exp Clin Pharmacol 5:101–105

    CAS  PubMed  Google Scholar 

  7. Davis WW, Stout TR (1971) Disc plate method of microbiological antibiotic assay. I. Factors influencing variability and error. Appl Microbiol 22:659–665

    CAS  PubMed  PubMed Central  Google Scholar 

  8. Woolfrey BF, Ramadei WA, Quall C (1979) Petri dish concavity—a potential source of error in antibiotic assay and agar diffusion antibiotic susceptibility tests. Am J Clin Pathol 71:433–436

    Article  CAS  PubMed  Google Scholar 

  9. Coyle M (ed) (2005) Manual of antimicrobial susceptibility testing. American Society for Microbiology, Washington

    Google Scholar 

  10. Biomerieux (2012) Etest antimicrobial susceptibility testing (package insert). Biomerieux, Marcy-l’Étoile

    Google Scholar 

  11. Stokell JR, Gharaibeh RZ, Steck TR (2013) Rapid emergence of a ceftazaidime-resistant Burkholderia multivorans strain in a cystic fibrosis patient. J Cyst Fibros 12:812–816

    Article  PubMed  Google Scholar 

Download references

Acknowledgements

This work was supported by NIH Grant (1R15HL126122-01) to T.R.S.

Author information

Authors and Affiliations

  1. Department of Biological Sciences, University of North Carolina - Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA

    J. Nicole Flanagan & Todd R. Steck

Authors
  1. J. Nicole Flanagan
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Todd R. Steck
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Todd R. Steck.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Flanagan, J.N., Steck, T.R. The Relationship Between Agar Thickness and Antimicrobial Susceptibility Testing. Indian J Microbiol 57, 503–506 (2017). https://doi.org/10.1007/s12088-017-0683-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12088-017-0683-z

Keywords

Search

Navigation