Multicenter study to assess the use of BL-DetecTool for the detection of CTX-M-type ESBLs and carbapenemases directly from clinical specimens.

Antimicrobial resistance (AMR) is one of the major public health problems worldwide. Multiple strategies have been put in place to address this problem. One of them is the rapid detection of the mechanisms of resistance, such as extended-spectrum beta-lactamases (ESBLs) and/or carbapenemases. We conducted a multicenter study that included nine European centers for the assessment of prototypes of a novel lateral flow immunoassay-based device (BL-DetecTool) for a rapid detection of ESBL (NG-Test CTX-M-MULTI DetecTool) and/or carbapenemases (NG-Test CARBA 5 DetecTool) from Enterobacterales and Pseudomonas aeruginosa in positive urine, positive blood cultures, and rectal swabs. We performed a prospective analysis between January 2021 and June 2022, including overall 22,010 samples. Based on each hospital information, the sensitivity to detect CTX-M was 84%-100%, 90.9%-100%, and 75%-100% for urine, positive blood cultures, and enriched rectal swabs, respectively. On the other hand, the sensitivity to detect carbapenemases was 42.8%-100%, 75%-100%, and 66.6%-100% for urine, positive blood cultures, and enriched rectal swab, respectively. BL-DetecTool allows a rapid and reliable detection of ESBL and carbapenemases directly from urine, positive blood cultures, or enriched rectal swabs, being an easy technique to implement in the workflow of clinical microbiology laboratories. IMPORTANCE: The assessed rapid assay to detect CTX-M beta-lactamases and carbapenemases directly from clinical samples can favor in the rapid detection of these mechanisms of resistance and hence the administration of a more adequate antimicrobial treatment.

Rapid detection of CTX-M-type ESBLs and carbapenemases directly from biological samples using the BL-DetecTool.

BACKGROUND: Lateral flow immunoassays (LFIA) have shown their usefulness for detecting CTX-M- and carbapenemase-producing Enterobacterales (CPEs) in bacterial cultures. Here, we have developed and validated the BL-DetecTool to detect CTX-M enzymes and carbapenemases directly from clinical samples. METHODS: The BL-DetecTool is an LFIA that integrates an easy sample preparation device named SPID (Sampling, Processing, Incubation and Detection). It was evaluated in three University hospitals on urine, blood culture (BC) and rectal swab (RS) specimens either of clinical origin or on spiked samples. RS evaluation was done directly and after a 24 h enrichment step. RESULTS: The CTX-M BL-DetecTool was tested on 485 samples (154 BC, 150 urines, and 181 RS) and revealed a sensitivity and specificity of 97.04% (95% CI 92.59%-99.19%) and 99.43% (95% CI 97.95%-99.93%), respectively. Similarly, the Carba5 BL-DetecTool was tested on 382 samples (145 BC, 116 urines, and 121 RS) and revealed a sensitivity and specificity of 95.3% (95% CI 89.43%-98.47%) and 100% (95% CI 98.67%-100%), respectively. While with the Carba5 BL-DetecTool five false negatives were observed, mostly in RS samples, with the CTX-M BL-DetecTool, in addition to four false-negatives, two false-positives were also observed. Direct testing of RS samples revealed a sensitivity of 78% and 86% for CTX-M and carbapenemase detection, respectively. CONCLUSIONS: BL-DetecTool showed excellent biological performance, was easy-to-use, rapid, and could be implemented in any microbiology laboratory around the world, without additional equipment, no need for electricity, nor trained personnel. It offers an attractive alternative to costly molecular methods.

A multicentre evaluation of the NG-test DetecTool OXA-23 for the rapid detection of OXA-23 carbapenemase directly from blood cultures.

Objectives: A multicentre study evaluating NG-Test DetecTool OXA-23 for the detection of OXA-23 carbapenemase directly from positive blood cultures (PBCs). Methods: The NG-Test DetecTool OXA-23 is an immunoassay that integrates a sample preparation device. We evaluated NG-Test DetecTool OXA-23 on 189 spiked and 126 clinical PBCs. The clinical samples' standard-of-care procedure consisted of bacterial identification from the first day of positivity by MALDI-TOF MS, conventional culture and antimicrobial susceptibility testing. The immunoassay results were verified molecularly. The strains used for the spiked samples consisted of well-characterized Acinetobacter baumannii and Proteus mirabilis strains. Results: The NG-Test DetecTool OXA-23 was evaluated on 315 PBCs and revealed sensitivity of 100% (95% CI: 98.21%-100.00%) and specificity of 100% (95% CI: 96.73%-100.00%). It provided 204 true-positive results for OXA-23 in 196 bottles with carbapenem-resistant A. baumannii (CRAB) and 8 bottles with carbapenem-resistant P. mirabilis and also provided 111 true-negative results. There were no false-positive and no false-negative results. Among the 315 PBCs studied, 83 clinical blood cultures collected in the ICU of a Greek university hospital, which were tested prospectively, all yielded CRAB, and OXA-23 was correctly detected in all samples from the first day of positivity using the NG-Test DetecTool OXA-23. Conclusions: The NG-Test DetecTool OXA-23 has exhibited excellent sensitivity and specificity for OXA-23 detection in PBCs and can provide valuable information for appropriate selection of antibiotic therapy and early implementation of infection control measures.