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1600. Closing the gap on moxifloxacin breakpoints for Stenotrophomonas maltophilia

BACKGROUND: Moxifloxacin (MOX) has in vitro activity against Enterobacterales and Stenotrophomonas maltophilia (SM). Although MOX commonly displays lower minimum inhibitory concentration (MIC)(50/90) values against SM when compared to levofloxacin, there are currently no established MOX breakpoints...

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Autores principales: Stone, Tyler J, Summers, Kate, Williamson, John, Palavecino, Elizabeth
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7776320/
http://dx.doi.org/10.1093/ofid/ofaa439.1780
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author Stone, Tyler J
Summers, Kate
Williamson, John
Palavecino, Elizabeth
Palavecino, Elizabeth
author_facet Stone, Tyler J
Summers, Kate
Williamson, John
Palavecino, Elizabeth
Palavecino, Elizabeth
author_sort Stone, Tyler J
collection PubMed
description BACKGROUND: Moxifloxacin (MOX) has in vitro activity against Enterobacterales and Stenotrophomonas maltophilia (SM). Although MOX commonly displays lower minimum inhibitory concentration (MIC)(50/90) values against SM when compared to levofloxacin, there are currently no established MOX breakpoints for treatment of SM. The Clinical and Laboratory Standards Institute (CLSI) has established interpretive categories and MIC breakpoints for levofloxacin (S ≤2µg/ml) against SM. The US Food and Drug Administration and European Committee on Antimicrobial Susceptibility Testing provide MOX breakpoints for Enterobacterales with susceptible MICs represented at ≤ 2 µg/mL and ≤ 0.25 µg/mL, respectively. The purpose of this study was to evaluate MOX MIC distribution against SM strains recovered from clinical specimens. METHODS: Clinical samples from patients with suspected infection during calendar year 2018 and 2019 were processed in the microbiology lab of Wake Forest Baptist Medical Center. After incubation, SM colonies were identified by MALDI-TOF system. MOX susceptibility testing was performed for these clinical isolates by gradient diffusion strip methodologies. Results were displayed as MIC (µg/mL) without interpretation. MIC(50/90) and susceptibility rates at potential breakpoints were calculated. RESULTS: A total of 211 isolates were tested, 112 from 2018 and 99 from 2019. MOX MIC(50) and MIC(90) for all isolates was 0.25 µg/mL and 2 µg/mL, respectively. The range of MIC distribution was ≤ 0.006 µg/mL to ≥ 64 µg/mL. Percent susceptibilities at incremental MICs, including established MOX breakpoints against Enterobacterales and established levofloxacin breakpoints against SM, are represented in Table 1. MIC distribution was plotted in Figure 1. Table 1. Susceptibility rates of S. maltophilia to moxifloxacin at theoretical breakpoints [Image: see text] Figure 1. Moxifloxacin MIC Distribution against All S. maltophilia Isolates [Image: see text] CONCLUSION: With no established breakpoint, these data represent one of the largest samples of MOX MICs against SM in the United States. Using the CLSI breakpoint for levofloxacin in SM (MIC of ≤2ug/ml) the overall susceptibility rate is 93%. This finding highlights the importance of performing susceptibility testing to this agent by the microbiology laboratory and the critical need for MOX breakpoints in SM. DISCLOSURES: Tyler J. Stone, PharmD, Paratek (Research Grant or Support) John Williamson, PharmD, Paratek (Research Grant or Support) Elizabeth Palavecino, MD, Paratek (Grant/Research Support)Paratek (Grant/Research Support)
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spelling pubmed-77763202021-01-07 1600. Closing the gap on moxifloxacin breakpoints for Stenotrophomonas maltophilia Stone, Tyler J Summers, Kate Williamson, John Palavecino, Elizabeth Palavecino, Elizabeth Open Forum Infect Dis Poster Abstracts BACKGROUND: Moxifloxacin (MOX) has in vitro activity against Enterobacterales and Stenotrophomonas maltophilia (SM). Although MOX commonly displays lower minimum inhibitory concentration (MIC)(50/90) values against SM when compared to levofloxacin, there are currently no established MOX breakpoints for treatment of SM. The Clinical and Laboratory Standards Institute (CLSI) has established interpretive categories and MIC breakpoints for levofloxacin (S ≤2µg/ml) against SM. The US Food and Drug Administration and European Committee on Antimicrobial Susceptibility Testing provide MOX breakpoints for Enterobacterales with susceptible MICs represented at ≤ 2 µg/mL and ≤ 0.25 µg/mL, respectively. The purpose of this study was to evaluate MOX MIC distribution against SM strains recovered from clinical specimens. METHODS: Clinical samples from patients with suspected infection during calendar year 2018 and 2019 were processed in the microbiology lab of Wake Forest Baptist Medical Center. After incubation, SM colonies were identified by MALDI-TOF system. MOX susceptibility testing was performed for these clinical isolates by gradient diffusion strip methodologies. Results were displayed as MIC (µg/mL) without interpretation. MIC(50/90) and susceptibility rates at potential breakpoints were calculated. RESULTS: A total of 211 isolates were tested, 112 from 2018 and 99 from 2019. MOX MIC(50) and MIC(90) for all isolates was 0.25 µg/mL and 2 µg/mL, respectively. The range of MIC distribution was ≤ 0.006 µg/mL to ≥ 64 µg/mL. Percent susceptibilities at incremental MICs, including established MOX breakpoints against Enterobacterales and established levofloxacin breakpoints against SM, are represented in Table 1. MIC distribution was plotted in Figure 1. Table 1. Susceptibility rates of S. maltophilia to moxifloxacin at theoretical breakpoints [Image: see text] Figure 1. Moxifloxacin MIC Distribution against All S. maltophilia Isolates [Image: see text] CONCLUSION: With no established breakpoint, these data represent one of the largest samples of MOX MICs against SM in the United States. Using the CLSI breakpoint for levofloxacin in SM (MIC of ≤2ug/ml) the overall susceptibility rate is 93%. This finding highlights the importance of performing susceptibility testing to this agent by the microbiology laboratory and the critical need for MOX breakpoints in SM. DISCLOSURES: Tyler J. Stone, PharmD, Paratek (Research Grant or Support) John Williamson, PharmD, Paratek (Research Grant or Support) Elizabeth Palavecino, MD, Paratek (Grant/Research Support)Paratek (Grant/Research Support) Oxford University Press 2020-12-31 /pmc/articles/PMC7776320/ http://dx.doi.org/10.1093/ofid/ofaa439.1780 Text en © The Author 2020. Published by Oxford University Press on behalf of Infectious Diseases Society of America. http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
spellingShingle Poster Abstracts
Stone, Tyler J
Summers, Kate
Williamson, John
Palavecino, Elizabeth
Palavecino, Elizabeth
1600. Closing the gap on moxifloxacin breakpoints for Stenotrophomonas maltophilia
title 1600. Closing the gap on moxifloxacin breakpoints for Stenotrophomonas maltophilia
title_full 1600. Closing the gap on moxifloxacin breakpoints for Stenotrophomonas maltophilia
title_fullStr 1600. Closing the gap on moxifloxacin breakpoints for Stenotrophomonas maltophilia
title_full_unstemmed 1600. Closing the gap on moxifloxacin breakpoints for Stenotrophomonas maltophilia
title_short 1600. Closing the gap on moxifloxacin breakpoints for Stenotrophomonas maltophilia
title_sort 1600. closing the gap on moxifloxacin breakpoints for stenotrophomonas maltophilia
topic Poster Abstracts
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7776320/
http://dx.doi.org/10.1093/ofid/ofaa439.1780
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