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Clinically Important Resistance among Salmonella enterica Serotype Typhi Isolates—United States, 2003–2015

BACKGROUND: Salmonella Typhi (Typhi) causes typhoid fever, accounting for an estimated 5,700 illnesses and 623 hospitalizations per year in the United States. Most infections are acquired during travel to regions outside the United States where typhoid fever is prevalent and antimicrobial resistance...

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Autores principales: Medalla, Felicita, Watkins, Louise Francois, Chatham-Stephens, Kevin, Reynolds, Jared, Bicknese, Amelia, Friedman, Cindy
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5631747/
http://dx.doi.org/10.1093/ofid/ofx163.890
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author Medalla, Felicita
Watkins, Louise Francois
Chatham-Stephens, Kevin
Reynolds, Jared
Bicknese, Amelia
Friedman, Cindy
author_facet Medalla, Felicita
Watkins, Louise Francois
Chatham-Stephens, Kevin
Reynolds, Jared
Bicknese, Amelia
Friedman, Cindy
author_sort Medalla, Felicita
collection PubMed
description BACKGROUND: Salmonella Typhi (Typhi) causes typhoid fever, accounting for an estimated 5,700 illnesses and 623 hospitalizations per year in the United States. Most infections are acquired during travel to regions outside the United States where typhoid fever is prevalent and antimicrobial resistance is a problem. Fluoroquinolones (e.g., ciprofloxacin) are considered the treatment of choice for susceptible Typhi infections due to their superior ability to concentrate intracellularly and in bile, however, nonsusceptibility has been associated with treatment failure or delayed response. Azithromycin and ceftriaxone are treatment options. We describe antimicrobial susceptibility among Typhi isolates in the United States and the implications for management. METHODS: The National Antimicrobial Resistance Monitoring System at CDC conducts susceptibility testing on all Typhi isolates submitted by public health laboratories. We used broth microdilution to determine minimum inhibitory concentrations (MICs) to agents representing 9 antimicrobial classes and categorized isolates according to criteria from the Clinical and Laboratory Standards Institute. We defined ciprofloxacin nonsusceptibility as MIC ≥0.12 μg/mL, ciprofloxacin resistance as MIC ≥1, azithromycin resistance as MIC ≥32, and ceftriaxone resistance as MIC ≥4. RESULTS: From 2003–2015, isolates were tested from 4,550 patients; 2,760 (61%) were ciprofloxacin nonsusceptible, 4% were ciprofloxacin resistant. One isolate was azithromycin resistant and none were ceftriaxone resistant. Ciprofloxacin nonsusceptibility increased from 39% in 2003 to 66% in 2015; resistance increased from 0.3% to 8%. Median age of patients was 23 years (range 1–99 years), 53% were male, most were from the Northeast (33%) or the West (29%), and 74% had an isolate from blood. CONCLUSION: Two thirds of Typhi isolates exhibited ciprofloxacin nonsusceptibility, which has increased over the last decade, and full resistance is increasing. Clinicians should be aware of high rates of fluoroquinolone nonsusceptibility when selecting empiric therapy and should tailor antimicrobial treatment to susceptibility results when feasible. Azithromycin and ceftriaxone remain important treatment options. DISCLOSURES: All authors: No reported disclosures.
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spelling pubmed-56317472017-11-07 Clinically Important Resistance among Salmonella enterica Serotype Typhi Isolates—United States, 2003–2015 Medalla, Felicita Watkins, Louise Francois Chatham-Stephens, Kevin Reynolds, Jared Bicknese, Amelia Friedman, Cindy Open Forum Infect Dis Abstracts BACKGROUND: Salmonella Typhi (Typhi) causes typhoid fever, accounting for an estimated 5,700 illnesses and 623 hospitalizations per year in the United States. Most infections are acquired during travel to regions outside the United States where typhoid fever is prevalent and antimicrobial resistance is a problem. Fluoroquinolones (e.g., ciprofloxacin) are considered the treatment of choice for susceptible Typhi infections due to their superior ability to concentrate intracellularly and in bile, however, nonsusceptibility has been associated with treatment failure or delayed response. Azithromycin and ceftriaxone are treatment options. We describe antimicrobial susceptibility among Typhi isolates in the United States and the implications for management. METHODS: The National Antimicrobial Resistance Monitoring System at CDC conducts susceptibility testing on all Typhi isolates submitted by public health laboratories. We used broth microdilution to determine minimum inhibitory concentrations (MICs) to agents representing 9 antimicrobial classes and categorized isolates according to criteria from the Clinical and Laboratory Standards Institute. We defined ciprofloxacin nonsusceptibility as MIC ≥0.12 μg/mL, ciprofloxacin resistance as MIC ≥1, azithromycin resistance as MIC ≥32, and ceftriaxone resistance as MIC ≥4. RESULTS: From 2003–2015, isolates were tested from 4,550 patients; 2,760 (61%) were ciprofloxacin nonsusceptible, 4% were ciprofloxacin resistant. One isolate was azithromycin resistant and none were ceftriaxone resistant. Ciprofloxacin nonsusceptibility increased from 39% in 2003 to 66% in 2015; resistance increased from 0.3% to 8%. Median age of patients was 23 years (range 1–99 years), 53% were male, most were from the Northeast (33%) or the West (29%), and 74% had an isolate from blood. CONCLUSION: Two thirds of Typhi isolates exhibited ciprofloxacin nonsusceptibility, which has increased over the last decade, and full resistance is increasing. Clinicians should be aware of high rates of fluoroquinolone nonsusceptibility when selecting empiric therapy and should tailor antimicrobial treatment to susceptibility results when feasible. Azithromycin and ceftriaxone remain important treatment options. DISCLOSURES: All authors: No reported disclosures. Oxford University Press 2017-10-04 /pmc/articles/PMC5631747/ http://dx.doi.org/10.1093/ofid/ofx163.890 Text en © The Author 2017. 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 Abstracts
Medalla, Felicita
Watkins, Louise Francois
Chatham-Stephens, Kevin
Reynolds, Jared
Bicknese, Amelia
Friedman, Cindy
Clinically Important Resistance among Salmonella enterica Serotype Typhi Isolates—United States, 2003–2015
title Clinically Important Resistance among Salmonella enterica Serotype Typhi Isolates—United States, 2003–2015
title_full Clinically Important Resistance among Salmonella enterica Serotype Typhi Isolates—United States, 2003–2015
title_fullStr Clinically Important Resistance among Salmonella enterica Serotype Typhi Isolates—United States, 2003–2015
title_full_unstemmed Clinically Important Resistance among Salmonella enterica Serotype Typhi Isolates—United States, 2003–2015
title_short Clinically Important Resistance among Salmonella enterica Serotype Typhi Isolates—United States, 2003–2015
title_sort clinically important resistance among salmonella enterica serotype typhi isolates—united states, 2003–2015
topic Abstracts
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5631747/
http://dx.doi.org/10.1093/ofid/ofx163.890
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