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Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory

BACKGROUND AND OBJECTIVES: Discovered in 1983, Extended spectrum beta-lactamase (ESBL) producers are still the leading cause of infections in India. Its prompt detection is crucial to the clinical management. The Clinical Laboratory Standards Institute (CLSI) recommends phenotypic screening and conf...

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Autores principales: Sahni, Rani Diana, Mathai, Dilip, Sudarsanam, Thambu David, Balaji, V, Brahamadathan, KN, Jesudasan, Mary V, Lalitha, MK
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Medknow Publications & Media Pvt Ltd 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6100337/
https://www.ncbi.nlm.nih.gov/pubmed/30166813
http://dx.doi.org/10.4103/jgid.jgid_49_17
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author Sahni, Rani Diana
Mathai, Dilip
Sudarsanam, Thambu David
Balaji, V
Brahamadathan, KN
Jesudasan, Mary V
Lalitha, MK
author_facet Sahni, Rani Diana
Mathai, Dilip
Sudarsanam, Thambu David
Balaji, V
Brahamadathan, KN
Jesudasan, Mary V
Lalitha, MK
author_sort Sahni, Rani Diana
collection PubMed
description BACKGROUND AND OBJECTIVES: Discovered in 1983, Extended spectrum beta-lactamase (ESBL) producers are still the leading cause of infections in India. Its prompt detection is crucial to the clinical management. The Clinical Laboratory Standards Institute (CLSI) recommends phenotypic screening and confirmatory tests to identify the ESBL producer making it cost and time consuming for the diagnostic laboratory. We compare here the screening and confirmatory tests offering a solution to the CLSI recommendation. METHODS: Nosocomial isolates E. coli (71) and K. pneumoniae (25) resistant to cefotaxime and ceftazidime were included. CLSI recommended testing with cefotaxime, ceftazidime and in combination with clavulanic acid by disk diffusion and agar dilution methods were performed. E-test was performed on discrepant results. To determine the genetic relatedness of the organisms, 22 Medical and Surgical ICU isolates were genotyped by PFGE. Dendrogram was constructed using dice co-efficient, UPGMA method with diversity database software. RESULTS AND CONCLUSIONS: Phenotypic screening disk diffusion test versus the confirmatory agar dilution MIC tests with cefotaxime and ceftazidime correlated well with the final ESBL status (kappa 0.852 and 0.905 P < 0.001) and (kappa 0.911 and 0.822 P < 0.001). The tests show 99-100% sensitivity, 75-83.3% specificity, and positive likelihood ratios between 4.0 -5.9. E-test confirmed 6 of 12 discordant results as ESBLs. Of the 96 nosocomial isolates screened as possible ESBL producers by the Kirby-Bauer disk diffusion test, 86.5% were confirmed ESBL producers. Genotyping on the ICU isolates by PFGE revealed a genetically diverse population suggesting no transmission of phenotypically similar ESBL strains within the ICUs.
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spelling pubmed-61003372018-08-30 Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory Sahni, Rani Diana Mathai, Dilip Sudarsanam, Thambu David Balaji, V Brahamadathan, KN Jesudasan, Mary V Lalitha, MK J Glob Infect Dis Original Article BACKGROUND AND OBJECTIVES: Discovered in 1983, Extended spectrum beta-lactamase (ESBL) producers are still the leading cause of infections in India. Its prompt detection is crucial to the clinical management. The Clinical Laboratory Standards Institute (CLSI) recommends phenotypic screening and confirmatory tests to identify the ESBL producer making it cost and time consuming for the diagnostic laboratory. We compare here the screening and confirmatory tests offering a solution to the CLSI recommendation. METHODS: Nosocomial isolates E. coli (71) and K. pneumoniae (25) resistant to cefotaxime and ceftazidime were included. CLSI recommended testing with cefotaxime, ceftazidime and in combination with clavulanic acid by disk diffusion and agar dilution methods were performed. E-test was performed on discrepant results. To determine the genetic relatedness of the organisms, 22 Medical and Surgical ICU isolates were genotyped by PFGE. Dendrogram was constructed using dice co-efficient, UPGMA method with diversity database software. RESULTS AND CONCLUSIONS: Phenotypic screening disk diffusion test versus the confirmatory agar dilution MIC tests with cefotaxime and ceftazidime correlated well with the final ESBL status (kappa 0.852 and 0.905 P < 0.001) and (kappa 0.911 and 0.822 P < 0.001). The tests show 99-100% sensitivity, 75-83.3% specificity, and positive likelihood ratios between 4.0 -5.9. E-test confirmed 6 of 12 discordant results as ESBLs. Of the 96 nosocomial isolates screened as possible ESBL producers by the Kirby-Bauer disk diffusion test, 86.5% were confirmed ESBL producers. Genotyping on the ICU isolates by PFGE revealed a genetically diverse population suggesting no transmission of phenotypically similar ESBL strains within the ICUs. Medknow Publications & Media Pvt Ltd 2018 /pmc/articles/PMC6100337/ /pubmed/30166813 http://dx.doi.org/10.4103/jgid.jgid_49_17 Text en Copyright: © 2018 Journal of Global Infectious Diseases http://creativecommons.org/licenses/by-nc-sa/4.0 This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.
spellingShingle Original Article
Sahni, Rani Diana
Mathai, Dilip
Sudarsanam, Thambu David
Balaji, V
Brahamadathan, KN
Jesudasan, Mary V
Lalitha, MK
Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory
title Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory
title_full Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory
title_fullStr Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory
title_full_unstemmed Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory
title_short Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory
title_sort extended-spectrum beta-lactamase producers: detection for the diagnostic laboratory
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6100337/
https://www.ncbi.nlm.nih.gov/pubmed/30166813
http://dx.doi.org/10.4103/jgid.jgid_49_17
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