Implementing EUCAST rapid antimicrobial susceptibility testing method for sepsis: lessons learned in a tertiary care center

  • Mohammad Aadam Bin Najeeb Department of Microbiology, NAMO Medical Education and Research Institute, Silvassa, Dadra and Nagar Haveli, India
  • Ayush Gupta Department of Microbiology, All India Institute of Medical Science (AIIMS), Bhopal, India
  • Shashank Purwar Department of Microbiology, All India Institute of Medical Science (AIIMS), Bhopal, India
  • Vishnu Teja Nallapati Department of Microbiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
  • Jogender Yadav Department of Microbiology, All India Institute of Medical Science (AIIMS), Bhopal, India
  • Farha Siddiqui Department of Microbiology, All India Institute of Medical Science (AIIMS), Bhopal, India
Keywords: RAST, EUCAST, sepsis, antimicrobial susceptibility testing, antimicrobial stewardship

Abstract

Introduction: We prospectively evaluated EUCAST rapid antimicrobial susceptibility testing methodology for susceptibility testing directly from blood culture bottles in comparison to CLSI disk-diffusion method.

Methodology: During May-November 2019, positively flagged blood culture bottles showing Gram-negative micro-organisms were simultaneously processed by rapid antimicrobial susceptibility testing and CLSI methodology. Antibiotics tested were cefotaxime, ceftazidime, piperacillin-tazobactam, imipenem, meropenem, gentamicin, tobramycin and trimethoprim-sulphamethoxazole.

Results: Overall, 80 isolates identified as Escherichia coli (n = 24, 30%), Klebsiella pneumoniae (n = 15, 18.7%), Pseudomonas aeruginosa (n = 16, 20%) and Acinetobacter baumannii (n = 25, 31.2%) were included. Categorical agreements  of rapid antimicrobial susceptibility testing at 4-, 6- and 8-hour reading times were 88.1% (304/345), 90.8% (425/468) and 92.3% (467/506), respectively. Major Error rates were 14% (21/150), 4.9% (10/206) and 4/236 (1.7%), whereas Very Major Error rates were 1.1% (2/177), 1.3% (3/232) and 3.3% (8/243), respectively. Results categorized as “Area of Technical Uncertainty” were significantly lower at 8-hour {10.2% (39/384) vs 5.2% (28/534), 4- vs 8-hour, p = 0.003, Fischer’s exact test}.

Conclusions: Except for a slightly higher Very major error rate, rapid antimicrobial susceptibility testing at 8-hour is equivalent to Disk-diffusion method (CLSI-M100) using CLSI-M52 criteria for equivalence: (Categorical agreement ≥ 90%, Very major error ≤ 1.5% and Major error ≤ 3%). Poor Categorical agreements at all reading times were noted for piperacillin-tazobactam, ciprofloxacin and E. coli. Performance of rapid antimicrobial susceptibility testing methodology in resource limited settings brings unique challenge of identifying micro-organisms within 8 hours. We suggest reading and reporting of results at a single time point using rapid antimicrobial susceptibility testing method i.e. at 8-hour.

Published
2021-06-30
How to Cite
1.
Bin Najeeb MA, Gupta A, Purwar S, Nallapati VT, Yadav J, Siddiqui F (2021) Implementing EUCAST rapid antimicrobial susceptibility testing method for sepsis: lessons learned in a tertiary care center. J Infect Dev Ctries 15:833-839. doi: 10.3855/jidc.13799
Section
Original Articles