Rapid identification and antimicrobial susceptibility testing of bacteria in bloodstream infections using the Accelerate ID/AST technology Price C1, Douglas I1, Tuttle E2, Shorr A3, Mensack M2, Bessesen M4, Miquirray S2, Overdier K1, Duarte N2, Shamsheyeva A2, Gamage D2, Allers E2, Hance K2, Michel C2, Turng B2, Metzger S2 1Denver Health and University of Colorado School of Medicine, Denver and Aurora, CO; 2Accelerate Diagnostics, Inc., Tucson, AZ; 3MedStar Washington Hospital Center and Georgetown University, Washington, DC; 4Denver Veteran’s Administration Medical Center and University of Colorado School of Medicine, Denver and Aurora, CO

OBJECTIVES: To evaluate the performance Table 1. ID results for the Accelerate ID/AST of the Accelerate ID/AST Technology for Technology compared to Vitek 2. identification and antimicrobial susceptibility testing directly on clinical blood culture Organism specimens.

METHODS: Fourteen clinical specimens (8 Gram-negative, 3 Gram-positive and 3 non- target) and six spiked blood cultures (6 Gram- (n) Tests Total Clinical Specimen(n) Spiked Specimen(n) Detected (n) Not Detected (n) negative) were tested. Twenty identification E. coli 7 3 4 7 0 tests were performed and 113 susceptibility Figure 1. Accelerate ID/AST Technology process flow. Klebsiella spp. 5 3 2 5 0 tests were performed using a panel of five Proteus spp. 1 1 0 1 0 Gram-positive (ceftaroline, doxycycline, concentration solution of each appropriate RESULTS: The Accelerate ID/AST erythromycin, linezolid, trimethoprim- antibiotic in cation-adjusted Mueller-Hinton Technology exhibited 95% overall agreement S.aureus 3 3 0 3 0 sulfamethoxazole) or seven Gram-negative broth with 0.94% agar. An algorithm converted with Vitek 2 for identification (Table 1) and 91% Non-Target 4 4 0 3 1* ( amikacin, ceftazidime, ceftriaxone, bacterial growth or inhibition in the presence of categorical agreement with disk diffusion for TOTAL 20 14 6 19 1 ciprofloxacin, gentamicin, piperacillin- antibiotic into a minimum inhibitory susceptibility testing (Table 2). Four tests were tazobactam, tobramycin) antibiotics. Remnant concentration (MIC) value. The results were excluded from analysis due to technical errors *False positive result. Shigella spp. detected by E. coli clinical positive blood culture specimens were compared to Vitek 2 for identification and disk and 10 minor errors were observed. probe obtained from Denver Health Medical Center, diffusion for susceptibility testing as comparator Identification results were produced in 1 hour Denver Veterans Affairs Eastern Colorado methods. and susceptibility results within 5 hours. Video 1. Ciprofloxacin-susceptible E coli Health Care System, and Washington Hospital progenitor cells growing into clones of daughter Center (Washington, DC). Spiked samples Table 2. Susceptibility test results for the Accelerate ID/AST Technology compared to disk diffusion. cells from 0 to 4 hours. Clones show were prepared by seeding 10 to 100 colony Antimicrobial Tests Total Test Total Positive Total Errors continuous growth in the growth control forming units into simulated blood culture (n) Failures (n) Matches (n) (n) channel (GC), but lyse in 1 µg/mL ciprofloxacin bottles (1 part of healthy donor blood + 4 parts Ceftaroline 3 0 3 0 (+CIP). Scale bar at lower right is 10 µm. of BD BACTEC Standard Aerobic media), and incubating for approximately 20-24 h. After a Doxycycline 3 0 2 1* sample aliquot was loaded onto the Accelerate Erythromycin 3 0 2 1* GC ID/AST Technology, part of the sample was subjected to a 1 hour growth step, while the Trimethoprim-Sulfamethoxazole 3 0 3 0 remaining sample underwent automated gel Linezolid 3 0 3 0 electro-filtration to reduce sample debris prior to Piperacillin-Tazobactam 14 0 11 3* +CIP pipetting it into independent flowcells of a disposable multichannel cassette. Electro- Ceftazidime 14 0 14 0 kinetic concentration immobilized cells onto the Ceftriaxone 14 1 11 2* CONCLUSION: This study showed the transparent lower surface of each flowcell Amikacin 14 0 14 0 technical feasibility of using the Accelerate ID/ channel. Immobilized cells were identified using AST Technology for identification and cocktails of fluorescently labeled Gentamicin 14 2 11 1* antimicrobial susceptibility testing directly on oligonucleotide probes and in situ hybridization. Tobramycin 14 0 13 1* clinical blood culture specimens. Further After the identification phase of the assay, the studies are needed to demonstrate the remaining sample was cleaned and Ciprofloxacin 14 1 12 1* performance of the technology on additional immobilized in separate flowcells as previously TOTAL 113 4 99 10* clinical specimen types. described followed by exposure to a single *minor error(s) Copyright © 2015 Contact: Connie S. Price, MD, Tel: +1-303-436-6000; Email: [email protected], For Research Use Only. Not for use in diagnostic procedures.