Work

Nanomotion-based technology for rapid antibiotic susceptibility testing among adult patients admitted to a tertiary-care hospital with Gram-negative bacteraemia: a prospective, single arm, comparative diagnostic accuracy study

Year: 2025

Type: article

Abstract: OBJECTIVE: Investigate performances and turnaround time of Resistell Phenotech antibiotic susceptibility testing (AST), a device using the new nanomotion technology, compared with reference methods. METHODS: This is a prospective, observational, and comparative diagnostic accuracy study including adult patients, who signed informed consent, hospitalized at a single 1200-bed tertiary-care centre in Switzerland, with Escherichia coli or Klebsiella pneumoniae bacteraemia from 18 June 2021 to 19 February 2024. Outcome measures were categorical agreement (very major discrepancies, major discrepancies, and minor discrepancies), as well as time from positive blood cultures to AST results, from matrix-assisted laser desoprtion ionisation time-of-flight mass spectrometry (MALDI-TOF MS) identification to AST results and AST start to end. Sensitivity, specificity, and accuracy were also assessed. VITEK 2 (Biomérieux) and Kirby-Bauer were used as reference directly on positive blood cultures per laboratory routine. The study was registered at ClinicalTrials.gov (NCT05002413). RESULTS: We included 253 adult patients, hospitalized with E. coli or K. pneumoniae bacteraemia. Resistell Phenotech AST showed 97.6% (95% CI, 94.6-99.0) (98.0% [95% CI, 94.2-99.3]) overall sensitivity compared with Kirby-Bauer (and VITEK 2). Concerning susceptibility, for both ceftriaxone-pathogen combinations, sensitivity reached 100% compared with Kirby-Bauer (E. coli 95% CI, 95.8-100.0; K. pneumoniae 95% CI, 89.0-100.0) (and VITEK 2 [E. coli 95% CI, 93.9-100.0; K. pneumoniae 95% CI, 85.7-100.0]); specificity was 94.1% (95% CI, 73.0-99.0) (91.7% [95% CI, 64.6-98.5]) for E. coli and 100% (72.2-100.0 Kirby-Bauer; 67.6-100.0 VITEK 2) for K. pneumoniae. Ciprofloxacin-E. coli reached 94.6% (95% CI, 87.9-97.7) (95.5% [95% CI, 87.6-98.5]) sensitivity and 83.3% (95% CI, 66.4-92.7) (79.2% [95% CI, 59.5-90.8]) specificity. The Resistell Phenotech AST analysis was >10 hours faster than reference method, averaging 15.7 hours (SD ± 6) from blood culture positivity to results, 10.9 (SD ± 7.3) from MALDI-TOF MS identification to AST, and 4.1 (SD ± 0.1) from start to end of AST. CONCLUSIONS: Nanomotion enables rapid AST with strong ceftriaxone results but needs improvement for ciprofloxacin. Further device developments are required, including multi-channel device and sensitive at high dose category.

Source: Clinical Microbiology and Infection

DOI: 10.1016/j.cmi.2025.10.016