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Improved blood culture workflow for faster identification of KPC-producing Enterobacterales

  • Bruna Mara Silva Seco
  • Juliana Coutinho Campos
  • Darlan Augusto da Costa Rocha
  • Aline Valerio de Lima
  • Fernanda Filomena de Oliveira
  • Mara Elisa Borsato Lemo
  • Suely Carlos Ferreira Sampaio
  • Jorge Luiz Mello Sampaio
Clinical Microbiology - Research Paper
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Abstract

Carba-NP original report for blood cultures described the need of subculture and mechanical lysis before testing, reaching the turnaround time of approximately 4 hours for sample preparation. We tested 100 consecutive blood cultures positive for Gram-negative bacilli on the Gram stain from a large clinical laboratory. Bacterial pellets were prepared by centrifugation and submitted to Carba-NP and Blue-Carba tests and used further to prepare smears for Vitek MS. Results obtained with colonies grown on sheep blood agar using the same methodologies were used as the gold standard. Carbapenemase genes were confirmed by PCR and DNA sequencing. Vitek MS identified correctly 86% of the samples. Of note, 7% of the samples were incorrectly reported by the instrument as containing a single isolate. KPC-2 was the predominant carbapenemase detected. There was 100% concordance for both negative and positive results for Carba-NP. In contrast, for Blue-Carba the concordance for positive results was 92.8%, and 41% of strains negative for carbapenemases presented a yellowish color on control well turning the test non-interpretable. The turnaround time for sample preparation for preparing the pellet was 13 min, and no subculture or mechanical lysis is needed when detecting KPC production in Enterobacterales.

Keywords

KPC Carbapenemases Carba-NP Blue-Carba Blood culture 

Notes

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Copyright information

© Sociedade Brasileira de Microbiologia 2018

Authors and Affiliations

  • Bruna Mara Silva Seco
    • 1
    • 2
    • 3
  • Juliana Coutinho Campos
    • 1
  • Darlan Augusto da Costa Rocha
    • 1
  • Aline Valerio de Lima
    • 1
  • Fernanda Filomena de Oliveira
    • 2
  • Mara Elisa Borsato Lemo
    • 2
  • Suely Carlos Ferreira Sampaio
    • 4
  • Jorge Luiz Mello Sampaio
    • 1
    • 2
  1. 1.School of Pharmacy, Clinical Microbiology and Antimicrobial Resistance LaboratoryUniversity of São PauloSão PauloBrazil
  2. 2.Fleury Medicine and Health, Microbiology SectionSão PauloBrazil
  3. 3.Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesBerlinGermany
  4. 4.Santa Casa de São Paulo School of Medical SciencesSão PauloBrazil

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