OXA-900, a Novel OXA Sub-Family Carbapenemase Identified in , Evades Detection by Commercial Molecular Diagnostics Tests.

Using whole-genome sequencing and cloning of the target gene, we identified carbapenemase, a novel belonging to a distant and distinct sub-family of . The plasmid-mediated gene was identified in a isolate with elevated carbapenem MICs that evaded detection by commercial DNA-based methods. The novel gene, an OXA-48 family carbapenem-hydrolyzing class D β-lactamase, OXA-900, likely originates from marine environmental .

Multiplex lateral flow immunochromatographic assay is an effective method to detect carbapenemases without risk of OXA-48-like cross reactivity.

Background: It is essential to detect carriers of carbapenemase-producing Enterobacterales in order to implement infection control measures. The objectives of this study was to evaluate the NG-Test CARBA 5 (CARBA 5) assay for detection of five carbapenemases and to assess the cross reactivity of other OXA-type carbapenemases with the OXA-48-like specific antibodies.

Methods: A total of 197 Enterobacterales isolates were tested.

Performance of Rapid Polymyxin™ NP and Rapid Polymyxin™ Acinetobacter for the detection of polymyxin resistance in carbapenem-resistant Acinetobacter baumannii and Enterobacterales.

Background: The global spread of carbapenem-resistant Enterobacterales (CRE) and Acinetobacter baumannii (CRAB) has prompted the reintroduction of colistin as a last-resort treatment. Although the recommended method for colistin susceptibility testing is broth microdilution (BMD), methods that are more rapid and easy to use are needed.

Objectives: To evaluate the performance of two commercial kits for colistin susceptibility testing: Rapid Polymyxin™ NP (RP-NP) for CRE and Rapid Polymyxin™ Acinetobacter (RP-AB) for CRAB.