Inter-laboratory calibration of quantitative analyses of antibiotic resistance genes

Jaqueline Rocha, Damiano Cacace, Ioannis Kampouris, Hélène Guilloteau, Thomas Jäger, Roberto B. M. Marano, Popi Karaolia, Célia M. Manaia*, Christophe Merlin, Despo Fatta-Kassinos, Eddie Cytryn, Thomas U. Berendonk, Thomas Schwartz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

57 Citations (Scopus)

Abstract

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are widely distributed in the environment where they represent potential public health threats. Quantitative PCR (qPCR) is a suitable approach to detect and quantify ARGs in environmental samples. However, the comparison of gene quantification data between different laboratories is challenging since the data are predominantly obtained under non-harmonized conditions, using different qPCR protocols. This study aimed at carrying out an inter-laboratory calibration in order to assess the variability inherent to the qPCR procedures for quantification of ARGs. With this aim, samples of treated wastewater collected in three different countries were analysed based on common DNA extract pools and identical protocols as well as distinct equipment, reagents batches, and operators. The genes analysed were the 16S rRNA, vanA, blaTEM, qnrS, sul1, blaCTXM-32 and intI1 and the artificial pNORM1 plasmid containing fragments from the seven targeted genes was used as a reference. The 16S rRNA gene was the most abundant, in all the analysed samples, followed by intI1, sul1, qnrS, and blaTEM, while blaCTXM-32 and vanA were below the limit of quantification in most or all the samples. For the genes 16S rRNA, sul1, intI1, blaTEM and qnrS the inter-laboratory variation was below 28% (3-8%, 6-18%, 8-21%, 10-24%, 15-28%, respectively). While it may be difficult to fully harmonize qPCR protocols due to equipment, reagents and operator variations, the inter-laboratory calibration is an adequate and necessary step to increase the reliability of comparative data on ARGs abundance in different environmental compartments and/or geographic regions.

Original languageEnglish
Article number102214
Pages (from-to)1-6
Number of pages6
JournalJournal of Environmental Chemical Engineering
Volume8
Issue number1
DOIs
Publication statusPublished - Feb 2020

Keywords

  • Antibiotic resistance gene
  • Inter-laboratory calibration
  • Quantitative PCR
  • Wastewater

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