1887

Abstract

The correlation of antimicrobial susceptibility testing (AST) between agar dilution and gradient diffusion for is not well established, especially in strains with high MICs.

The objective of this study was to evaluate the accuracy of gradient diffusion for .

Fifty strains of , all tested by the agar dilution method according to CLSI methods and confirmed to be genetically distinct using molecular typing (NG-MAST), were selected. Isolates with high MICs were targeted. Gradient diffusion was performed for ceftriaxone (CRO), cefixime (CFX), azithromycin (AZT), tetracycline (TET) and fosfomycin (FOS) using two different commercial antimicrobial strips on different culture media (a non-commercial GC agar base with 1 % defined growth supplement and two commercial media). The performance of agar gradient diffusion was assessed based on accuracy, using essential and category agreements (EA and CA).

Essential and categorical agreement were over 90 % for CRO, CFX and AZT on the two commercial agar media tested. Category disagreements were seen for CFX and AZT, mostly just very major errors. For TET, EA ranged from 80 to 96 % and CA ranged from 38 to 76 %, most of the misclassifications being minor errors. Finally, EA for FOS ranged between 80 and 98 %.

Gradient diffusion is an accurate and acceptable alternative for CRO, CFX and AZT. Caution is advised when MICs are reported by gradient diffusion approach breakpoints because of the possibility of very major errors. The use of gradient diffusion is limited for TET because of the high rate of minor errors.

Loading

Article metrics loading...

/content/journal/acmi/10.1099/acmi.0.000116
2020-03-25
2020-04-01
Loading full text...

Full text loading...

/deliver/fulltext/acmi/10.1099/acmi.0.000116/acmi000116.html?itemId=/content/journal/acmi/10.1099/acmi.0.000116&mimeType=html&fmt=ahah

References

  1. WHO Global action plan to control the spread and impact of antimicrobial resistance in Neisseria gonorrhoeae 2012. http://apps.who.int/iris/bitstream/10665/44863/1/9789241503501_eng.pdf
  2. Lefebvre B, Labbe AC. Surveillance des souches de Neisseria gonorrhoeae résistantes aux antibiotiques dans la province de Québec 2018. Available from: https://www.inspq.qc.ca/sites/default/files/publications/2558_surveillance_neisseria_gon%20271%20orrhoeae_resistantes_antibiotiques.pdf.
  3. Lefebvre B, Martin I, Demczuk W, Deshaies L, Michaud S et al. Ceftriaxone-Resistant Neisseria gonorrhoeae, Canada, 2017. Emerg Infect Dis 2018; 24:381–383 [CrossRef]
    [Google Scholar]
  4. Institut national d’excellence en santé et en services sociaux Infection non compliquée Chlamydia trachomatis ou Neisseria gonorrhoeae 2018. Available from: https://www.inesss.qc.ca/fileadmin/doc/INESSS/Outils/Guides_ITSS/Guide_ITSS-Chlamydia_gonorrhoeae.pdf.
  5. CLSI Performance Standards for Antimicrobial Susceptibility Testing, 29th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2019
    [Google Scholar]
  6. CLSI Performance Standards for Antimicrobial Susceptibility Testing, 28th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2018
    [Google Scholar]
  7. Shende T, Sood S, Singh R, Kapil A, Kar HK et al. Comparison of E test and agar dilution for testing activity of ceftriaxone against Neisseria gonorrhoeae. J Med Microbiol 2016; 65:701–702 [CrossRef][PubMed]
    [Google Scholar]
  8. Papp JR, Rowlinson M-C, O'Connor NP, Wholehan J, Razeq JH et al. Accuracy and reproducibility of the Etest to detect drug-resistant Neisseria gonorrhoeae to contemporary treatment. J Med Microbiol 2018; 67:68–73 [CrossRef][PubMed]
    [Google Scholar]
  9. Enriquez RP, Goire N, Kundu R, Gatus BJ, Lahra MM. A comparison of agar dilution with the calibrated dichotomous sensitivity (CDS) and Etest methods for determining the minimum inhibitory concentration of ceftriaxone against Neisseria gonorrhoeae. Diagn Microbiol Infect Dis 2016; 86:40–43 [CrossRef][PubMed]
    [Google Scholar]
  10. Unemo M, Bradshaw CS, Hocking JS, de Vries HJC, Francis SC et al. Sexually transmitted infections: challenges ahead. Lancet Infect Dis 2017; 17:e235–e279 [CrossRef][PubMed]
    [Google Scholar]
  11. Unemo M, Golparian D, Sánchez-Busó L, Grad Y, Jacobsson S et al. The novel 2016 WHO Neisseria gonorrhoeae reference strains for global quality assurance of laboratory investigations: phenotypic, genetic and reference genome characterization. J Antimicrob Chemother 2016; 71:3096–3108 [CrossRef][PubMed]
    [Google Scholar]
  12. Martin IMC, Ison CA, Aanensen DM, Fenton KA, Spratt BG. Rapid sequence-based identification of gonococcal transmission clusters in a large metropolitan area. J Infect Dis 2004; 189:1497–1505 [CrossRef][PubMed]
    [Google Scholar]
  13. CLSI Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically; Approved Standard - Eleventh Edition. M07-A11 Wayne, PA: Clinical and Laboratory Standards Institute; 2018
    [Google Scholar]
  14. World Health Organization Laboratory diagnosis of sexually transmitted infections, including human immunodeficiency virus 2013. Available from: https://apps.who.int/iris/bitstream/handle/10665/85343/9789241505840_eng.pdf;jsessionid=EF88EE8CDA619C879F9DAF531C8F256E?sequence=1.
  15. CLSI Performance Standards for Antimicrobial Disk Susceptibility Tests; Approved Standard - Twelfth Edition M02-A12 Wayne, PA: Clinical and Laboratory Standards Institute; 2015
    [Google Scholar]
  16. CLSI Verification of Commercial Microbial Identification and Antimicrobial Susceptibility Testing Systems. CLSI guidelines M52, 1st ed. CLSI guideline M52. Wayne, PA: Clinical and Laboratory Standards Institute; 2015
    [Google Scholar]
  17. Liu H, Taylor TH, Pettus K, Trees D. Assessment of Etest as an alternative to agar dilution for antimicrobial susceptibility testing of Neisseria gonorrhoeae. J Clin Microbiol 2014; 52:1435–1440 [CrossRef][PubMed]
    [Google Scholar]
  18. Yeung KH, Ng LK, Dillon JA. Evaluation of Etest for testing antimicrobial susceptibilities of Neisseria gonorrhoeae isolates with different growth media. J Clin Microbiol 1993; 31:3053–3055 [CrossRef][PubMed]
    [Google Scholar]
  19. Mal PB, Jabeen K, Farooqi J, Unemo M, Khan E. Antimicrobial susceptibility testing of Neisseria gonorrhoeae isolates in Pakistan by Etest compared to calibrated dichotomous sensitivity and clinical laboratory Standards Institute disc diffusion techniques. BMC Microbiol 2016; 16:236 [CrossRef][PubMed]
    [Google Scholar]
  20. Jones RN, Gavan TL, Thornsberry C, Fuchs PC, Gerlach EH et al. Standardization of disk diffusion and agar dilution susceptibility tests for Neisseria gonorrhoeae: interpretive criteria and quality control guidelines for ceftriaxone, penicillin, spectinomycin, and tetracycline. J Clin Microbiol 1989; 27:2758–2766 [CrossRef][PubMed]
    [Google Scholar]
  21. Singh V, Bala M, Kakran M, Ramesh V. Comparative assessment of CDS, CLSI disc diffusion and Etest techniques for antimicrobial susceptibility testing of Neisseria gonorrhoeae: a 6-year study. BMJ Open 2012; 2:e000969 02 07 2012 [CrossRef][PubMed]
    [Google Scholar]
  22. Tesh LD, Shaeer KM, Cho JC, Estrada SJ, Huang V et al. Neisseria gonorrhoeae and fosfomycin: past, present and future. Int J Antimicrob Agents 2015; 46:290–296 [CrossRef][PubMed]
    [Google Scholar]
  23. Gose S, Kong CJ, Lee Y, Samuel MC, Bauer HM et al. Comparison of Neisseria gonorrhoeae MICs obtained by Etest and agar dilution for ceftriaxone, cefpodoxime, cefixime and azithromycin. J Microbiol Methods 2013; 95:379–380 [CrossRef][PubMed]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/acmi/10.1099/acmi.0.000116
Loading
/content/journal/acmi/10.1099/acmi.0.000116
Loading

Data & Media loading...

Supplements

Supplementary material 1

PDF
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error