Journal of Global Infectious DiseasesOfficial Publishing of INDUSEM and OPUS 12 Foundation, Inc. Users online:1234  
Print this pageEmail this pageSmall font sizeDefault font sizeIncrease font size     
Home About us Editors Ahead of Print Current Issue Archives Search Instructions Subscribe Advertise Login 
Year : 2018  |  Volume : 10  |  Issue : 3  |  Page : 140-146

Extended-spectrum beta-lactamase producers: Detection for the diagnostic laboratory

1 Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
2 Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India

Correspondence Address:
Dr. Rani Diana Sahni
Department of Clinical Microbiology, Christian Medical College, Vellore - 632 004, Tamil Nadu
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jgid.jgid_49_17

Rights and Permissions

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.

Print this article     Email this article
 Next article
 Previous article
 Table of Contents

 Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
 Citation Manager
 Access Statistics
 Reader Comments
 Email Alert *
 Add to My List *
 * Requires registration (Free)

 Article Access Statistics
    PDF Downloaded31    
    Comments [Add]    

Recommend this journal


Sitemap | What's New | Feedback | Copyright and Disclaimer | Contact Us
2008 Journal of Global Infectious Diseases | Published by Wolters Kluwer - Medknow
Online since 10th December, 2008