Rapid pathogen identification (ID) and antimicrobial susceptibility testing (AST) of bacteria-causing bloodstream infections can improve patients’ outcome. In this study, we evaluated the performance of Alfred60AST (Alifax) which provides AST directly on positive blood culture (BC) bottles by light scattering. In a selected group of patients with a clinical suspicion of severe sepsis or at risk for infections with multiresistant organisms, we compared Alfred60AST AST results with traditional AST results (Vitek2 (bioMérieux) or disk diffusion). Discrepancy analysis was performed by Etest (bioMérieux) or broth microdilution. In total, 222 samples were evaluated. On 595 susceptibility determinations, 93.4% showed categorical agreement (CA) with the standard method. Eighty-one percent of isolates showed a 100% categorical agreement (CA) which increased to 84.3% after discrepancy analysis. There were 8 very major discrepancies (VMD), 18 major discrepancies (MD), and 13 minor discrepancies (MiD). Most discrepant results were observed for piperacillin-tazobactam (15.6%) and clindamycin (18.9%). Analysis time was 6–6.5 h for a complete Alfred60AST AST result. In addition, we evaluated the behavior of clinicians in adjusting antibiotic therapy according to the routine AST results. In 37% of all patients, antibiotic therapy was altered after reporting of AST result and adjustment was more frequent for Gram-negative than for Gram-positive isolates. With some improvements, Alfred60AST provides accurate and rapid preliminary AST results for organisms causing bloodstream infections and may have at least a potential clinical benefit in about one-third of patients with severe sepsis, by delivering faster results compared with conventional methods.
This is a preview of subscription content, log in to check access.
Buy single article
Instant unlimited access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Sherwin R, Winters ME, Vilke GM, Wardi G (2017) Does early and appropriate antibiotic administration improve mortality in emergency department patients with severe sepsis or septic shock?," (in eng). J Emerg Med 53(4):588–595. https://doi.org/10.1016/j.jemermed.2016.12.009
Van den Poel B, Klak A, Desmet S, Verhaegen J (2018) How small modifications in laboratory workflow of blood cultures can have a significant impact on time to results," (in eng). Eur J Clin Microbiol Infect Dis. https://doi.org/10.1007/s10096-018-3309-4
Deresinski S (2007) Principles of antibiotic therapy in severe infections: optimizing the therapeutic approach by use of laboratory and clinical data," (in eng). Clin Infect Dis 45(Suppl 3):S177–S183. https://doi.org/10.1086/519472
Kerremans JJ et al (2008) Rapid identification and antimicrobial susceptibility testing reduce antibiotic use and accelerate pathogen-directed antibiotic use," (in eng). J Antimicrob Chemother 61(2):428–435. https://doi.org/10.1093/jac/dkm497
Huang AM et al (2013) Impact of rapid organism identification via matrix-assisted laser desorption/ionization time-of-flight combined with antimicrobial stewardship team intervention in adult patients with bacteremia and candidemia," (in eng). Clin Infect Dis 57(9):1237–1245. https://doi.org/10.1093/cid/cit498
Kumar A et al (2006) Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock," (in eng). Crit Care Med 34(6):1589–1596. https://doi.org/10.1097/01.CCM.0000217961.75225.E9
Verroken A et al (2016) Clinical impact of MALDI-TOF MS identification and rapid susceptibility testing on adequate antimicrobial treatment in sepsis with positive blood cultures," (in eng). PLoS One 11(5):e0156299. https://doi.org/10.1371/journal.pone.0156299
French K, Evans J, Tanner H, Gossain S, Hussain A (2016) The clinical impact of rapid, direct MALDI-ToF identification of bacteria from positive blood cultures," (in eng). PLoS One 11(12):e0169332. https://doi.org/10.1371/journal.pone.0169332
Köck R, Wüllenweber J, Horn D, Lanckohr C, Becker K, Idelevich EA (2017) Implementation of short incubation MALDI-TOF MS identification from positive blood cultures in routine diagnostics and effects on empiric antimicrobial therapy," (in eng). Antimicrob Resist Infect Control 6:12. https://doi.org/10.1186/s13756-017-0173-4
Charnot-Katsikas A et al (2018) Use of the accelerate pheno system for identification and antimicrobial susceptibility testing of pathogens in positive blood cultures and impact on time to results and workflow, (in eng). J Clin Microbiol 56(1). https://doi.org/10.1128/JCM.01166-17
Barnini S, Brucculeri V, Morici P, Ghelardi E, Florio W, Lupetti A (2016) A new rapid method for direct antimicrobial susceptibility testing of bacteria from positive blood cultures," (in eng). BMC Microbiol 16(1):185. https://doi.org/10.1186/s12866-016-0805-5
Fontana C, Favaro M, Bossa MC, Minelli S, Altieri A, Favalli C (2016) “Clinical antimicrobial susceptibility testing as a routine expercience.,” presented at the ECCMID 2016, Amsterdam
Cellini A, Pedna MF, Tango N, Sambri V (2015) “Evaluation of automated methodology to streak, identify and antibiogramming starting from positive blood.,” presented at the ECCMID 2015, Copenhagen
Giordano C, Brucculeri V, Lelli L, Lupetti A, Barnini S Improving the concordance between the rapid antimicrobial susceptibility test and the traditional semi-automated antimicrobial susceptibility test. Microbiology Unit, Azienda Ospedaliero-Universitaria Pisana, Pisa
Sánchez-Carrillo C et al (2019) Evaluation of the Alfred AST® system for rapid antimicrobial susceptibility testing directly from positive blood cultures," (in eng). Eur J Clin Microbiol Infect Dis. https://doi.org/10.1007/s10096-019-03595-y
Giordano C, Piccoli E, Vryccykeri V, Barnini S (2018) "A prospective evaluation of two rapid phenotypical antimicrobial susceptibility technologies for the diagnostic stewardship of sepsis.," vol. 2018, ed. BioMed Research International, p 13
Zboromyrska Y et al (2016) "The evaluation of Uro4 HB&L™for rapid susceptibility testing of Gram-negative bacteria isolated in a blood culture. ," presented at the ECCMID 2016, Amsterdam, The Netherlands
Olivieri C et al (2010) "Rapid assessment of antibiotic susceptibility in positive blood cultures.," presented at the European Society of Intensive Care Medicine (ESICM). Annual Congress., Barcelona, Spain
Desmet S et al (2016) Development of a national EUCAST challenge panel for antimicrobial susceptibility testing," (in eng). Clin Microbiol Infect 22(8):704–710. https://doi.org/10.1016/j.cmi.2016.05.011
Wayne P (2014) "Verification of microbial identification and antimicrobial susceptibility testing systems. CLSI document M52," 1st ed. ed. Clinical and Laboratory Standards Institute
Jorgensen JH (1993) Selection criteria for an antimicrobial susceptibility testing system," (in eng). J Clin Microbiol 31(11):2841–2844
Verroken A, Defourny L, Lechgar L, Magnette A, Delmée M, Glupczynski Y (2015) Reducing time to identification of positive blood cultures with MALDI-TOF MS analysis after a 5-h subculture," (in eng). Eur J Clin Microbiol Infect Dis 34(2):405–413. https://doi.org/10.1007/s10096-014-2242-4
Zabbe JB, Zanardo L, Mégraud F, Bessède E (2015) MALDI-TOF mass spectrometry for early identification of bacteria grown in blood culture bottles," (in eng). J Microbiol Methods 115:45–46. https://doi.org/10.1016/j.mimet.2015.04.009
Idelevich EA, Schüle I, Grünastel B, Wüllenweber J, Peters G, Becker K (2014) Rapid identification of microorganisms from positive blood cultures by MALDI-TOF mass spectrometry subsequent to very short-term incubation on solid medium," (in eng). Clin Microbiol Infect 20(10):1001–1006. https://doi.org/10.1111/1469-0691.12640
Fitzgerald C et al (2016) Rapid identification and antimicrobial susceptibility testing of positive blood cultures using MALDI-TOF MS and a modification of the standardised disc diffusion test: a pilot study," (in eng). J Clin Pathol. https://doi.org/10.1136/jclinpath-2015-203436
Hayakawa K et al (2017) Impact of rapid identification of positive blood cultures using the Verigene system on antibiotic prescriptions: a prospective study of community-onset bacteremia in a tertiary hospital in Japan," (in eng). PLoS One 12(7):e0181548. https://doi.org/10.1371/journal.pone.0181548
Meda M et al (2017) What are the critical steps in processing blood cultures? A prospective audit evaluating current practice of reporting blood cultures in a centralised laboratory serving secondary care hospitals," (in eng). J Clin Pathol 70(4):361–366. https://doi.org/10.1136/jclinpath-2016-204091
Menon V, Lahanas S, Janto C, Lee A (2016) Utility of direct susceptibility testing on blood cultures: is it still worthwhile?," (in eng). J Med Microbiol 65(6):501–509. https://doi.org/10.1099/jmm.0.000259
We thank Alifax® SpA (Italy) for providing the device and reagents to perform this study.
Conflict of interest
The authors declare that they have no conflict of interest.
This study protocol was approved by the Ethical Committee of the University Hospital of Leuven.
No informed consent was needed for this study since no personal data were involved.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Van den Poel, B., Meersseman, P., Debaveye, Y. et al. Performance and potential clinical impact of Alfred60AST (Alifax®) for direct antimicrobial susceptibility testing on positive blood culture bottles. Eur J Clin Microbiol Infect Dis 39, 53–63 (2020) doi:10.1007/s10096-019-03690-0
- Direct antimicrobial susceptibility testing
- Blood culture
- Clinical impact