Multicentric evaluation of the MTS™ Synergy Application System for reliable antibiotic synergy testing in clinical laboratories
Year: 2025
Type: article
Abstract: • In vitro synergy testing has the potential for improving antimicrobial therapy • Concordance of different synergy tests has not been well-defined yet • We evaluate MTS-SAS® to determine the synergistic interactions of antimicrobials • MTS-SAS® represents a simple and reliable commercial diagnostic assay • MTS-SAS® reduce the labour time and suggest its role in the laboratory workflow The rise of antimicrobial resistance poses a major challenge for both clinicians and clinical microbiologists. There is an increasing need for user-friendly and reliable methods to assess the activity of antibiotics against multidrug-resistant (MDR) strains. Although synergy testing provides valuable insights, conventional methods such as checkerboard assays and time-kill studies are labor-intensive, technically demanding, and difficult to standardize. This study evaluated the MTS-SAS® (MIC Test Strip – Synergy Application System, Liofilchem®, Italy), a commercial gradient diffusion assay developed for antibiotic synergy testing. The performance of MTS-SAS® was evaluated in comparison with the checkerboard microdilution method, used as the reference standard. Nine antibiotic combinations were tested against ten different bacterial strains across 11 Italian hospitals. Inter-laboratory reproducibility and agreement with the reference method were analyzed. The concordance between MIC test strips and the broth microdilution (BMD) method was 98.4%, with 1.6% showing discordant results – all within a three-dilution range. Among 996 synergy determinations, MTS-SAS® demonstrated high reproducibility across all centers (96.7%), while only 3.3% of tests showed discordant synergy classifications (e.g., synergy vs. indifference). Comparison with the checkerboard method demonstrated an overall concordance of 96.2%, despite the absence of specific operator training at each site. These findings support MTS-SAS® as a practical and reliable alternative to conventional synergy testing methods, particularly suitable for routine clinical settings and laboratories lacking advanced microbiological expertise.
Authors: Edoardo Carretto, Stefano Andreoni, Richard Aschbacher, Daniela Barbarini, Simone Bramati, Flavia Brovarone, Claudio Farina, Angela Papa, Andrea Rocchetti, Giuseppe Russello, Vittorio Sambri, Assunta Sartor, Paolo Gaibani
Institutions: Azienda Sanitaria Unità Locale di Reggio Emilia, Azienda Ospedaliero Universitaria Maggiore della Carita, Azienda Sanitaria dell'Alto Adige, Policlinico San Matteo Fondazione, Ospedale Santa Chiara, Provincia Autonoma di Trento, Ospedale Papa Giovanni XXIII, Azienda Socio Sanitaria Territoriale Lariana, Azienda Ospedaliera Nazionale SS. Antonio e Biagio e Cesare Arrigo, University of Bologna, Azienda sanitaria universitaria Friuli Centrale, University of Verona, Azienda Ospedaliera Universitaria Integrata Verona
Language: English
Subfield: Clinical Biochemistry
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $1,890
Funder: Ministero della Salute
Award: G1386110767
OpenAlex ID: W7116108199