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A. Masseron, L. Poirel, L. Falgenhauer, C. Imirzalioglu, J. Kessler, T. Chakraborty, P. Nordmann:
"Ongoing dissemination of OXA-244 carbapenemase-producing Escherichia coli in Switzerland and their detection";
Diagnostic Microbiology and Infectious Disease, 97/3 (2020), 115059; 5 pages.

OXA-244 is a derivative of OXA-48 showing weaker carbapenemase activity, compromising the detection of corresponding producers in clinical laboratories. Since 2017, the Swiss National Reference Center for Emerging Antibiotic Resistance noticed an increased identification of OXA-244-producing Escherichia coli (n=15) within the country. Different methods (biochemical and immunoassay tests, screening culture media) were tested for the detection of OXA-244 producers. Whole genome sequencing was used to investigate the genetic relatedness between the isolates and the genetic structures at the origin of the acquisition of the blaOXA-244 gene. The mSuperCARBA® medium and the NG-Test CARBA5 assay were found to be suitable tools for detecting all OXA-244-producing isolates. Other selectivemedia did not perform optimally. Among the fifteen strains, five sequence types were identified, with ST38 being predominant. The blaOXA-244 gene was located on the chromosome for all isolates. Overall, detection of OXA-244 producers is challenging and specific guidelinesmust be followed.

http://dx.doi.org/10.1016/j.diagmicrobio.2020.115059