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Evaluation of ComASP oritavancin test for rapid antibiotic susceptibility testing of Gram-positive clinical isolates
ESCMID eLearning. Lazzaro L. 07/09/21; 328476; 1985
Mr. Lorenzo M. Lazzaro
Mr. Lorenzo M. Lazzaro
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Abstract
Discussion Forum (0)
Abstract number: 1985

Session Type: ePosters

Session Title: ePosters

Authors(s): L.M. Lazzaro, M. Cassisi, S. Stefani, F. Campanile

Authors Affiliations(s): University of Catania, Department of Biomedical and Biotechnological Sciences (BIOMETEC),, Italy

Background:

Oritavancin is a novel lipoglycopeptide approved by the FDA and the EMA for the treatment of acute bacterial skin and skin structure infections (ABSSSI) sustained by staphylococci, including methicillin resistant Staphylococcus aureus (MRSA), streptococci and enterococci.

Our aim was to compare the rapid Compact Antimicrobial Susceptibility Panel (ComASP®) for oritavancin susceptibility testing to the broth microdilution (BMD) reference method, against S. aureus and vancomycin-resistant enterococci (VRE) clinical isolates.

Methods:

Oritavancin antimicrobial susceptibility testing (AST) was performed by BMD method following CLSI and EUCAST guidelines, against 40 VRE belonging to VanA and VanB phenotypes (30 E.faecium; 10 E.faecalis) and 40 S.aureus (20 MSSA; 20 MRSA) belonging to several STs. The ComASP Oritavancin test - consisting of a 2-test panel with dried antibiotic in 15 two-fold dilutions (0.001-16μg/ml) - was performed as recommended by the manufacturer (Liofilchem, Roseto degli Abruzzi, Italy).

Results:

According to the CLSI breakpoints (susceptibility MICs ≤0.12 mg/L), oritavancin inhibited 62.5% of the VRE strains (MIC50 0.12/MIC90 0.5 mg/L), by the BMD reference method. Among VanA strains, 30% of E.faecium and 50% of E.faecalis strains were oritavancin non-susceptible (ORI-NS) (MICs 0.25-1 mg/L). Among VanB strains, only one E.faecalis was ORI-NS (MIC 0.25 mg/L).

The comparison between ComASP Oritavancin and BMD reference method for VRE showed a Categorical agreement (CA) of 90.2% and an Essential agreement (EA) of 95.1% (fig.1A).

Oritavancin inhibited 35% of the S. aureus isolates (MIC50 0.25/MIC90 1 mg/L) (CLSI/EUCAST breakpoints). Among ORI-NS strains, 35% were MSSA (MICs 0.5-4 mg/L), mainly belonging to ST8, while 30% were MRSA (MICs 0.25-0.5 mg/L), mainly belonging to ST8 and 228.

The comparison between ComASP Oritavancin and the BMD reference method for all S. aureus tested demonstrated a CA of 97.5% and an EA of 100% (fig.1B).

Conclusions:

The ComASP Oritavancin system was developed to perform the BMD method for AST as recommended by international standards (CLSI; EUCAST). Our results obtained by comparing the ComASP Oritavancin system with the BMD reference method confirmed the reliability to test oritavancin susceptibility by Liofilchem panel. It is easy and rapid to use, and could contribute to reducing the turnaround for hospital laboratories.

Keyword(s): Oritavancin, Compact Antimicrobial Susceptibility Panel, Gram-positive

Abstract number: 1985

Session Type: ePosters

Session Title: ePosters

Authors(s): L.M. Lazzaro, M. Cassisi, S. Stefani, F. Campanile

Authors Affiliations(s): University of Catania, Department of Biomedical and Biotechnological Sciences (BIOMETEC),, Italy

Background:

Oritavancin is a novel lipoglycopeptide approved by the FDA and the EMA for the treatment of acute bacterial skin and skin structure infections (ABSSSI) sustained by staphylococci, including methicillin resistant Staphylococcus aureus (MRSA), streptococci and enterococci.

Our aim was to compare the rapid Compact Antimicrobial Susceptibility Panel (ComASP®) for oritavancin susceptibility testing to the broth microdilution (BMD) reference method, against S. aureus and vancomycin-resistant enterococci (VRE) clinical isolates.

Methods:

Oritavancin antimicrobial susceptibility testing (AST) was performed by BMD method following CLSI and EUCAST guidelines, against 40 VRE belonging to VanA and VanB phenotypes (30 E.faecium; 10 E.faecalis) and 40 S.aureus (20 MSSA; 20 MRSA) belonging to several STs. The ComASP Oritavancin test - consisting of a 2-test panel with dried antibiotic in 15 two-fold dilutions (0.001-16μg/ml) - was performed as recommended by the manufacturer (Liofilchem, Roseto degli Abruzzi, Italy).

Results:

According to the CLSI breakpoints (susceptibility MICs ≤0.12 mg/L), oritavancin inhibited 62.5% of the VRE strains (MIC50 0.12/MIC90 0.5 mg/L), by the BMD reference method. Among VanA strains, 30% of E.faecium and 50% of E.faecalis strains were oritavancin non-susceptible (ORI-NS) (MICs 0.25-1 mg/L). Among VanB strains, only one E.faecalis was ORI-NS (MIC 0.25 mg/L).

The comparison between ComASP Oritavancin and BMD reference method for VRE showed a Categorical agreement (CA) of 90.2% and an Essential agreement (EA) of 95.1% (fig.1A).

Oritavancin inhibited 35% of the S. aureus isolates (MIC50 0.25/MIC90 1 mg/L) (CLSI/EUCAST breakpoints). Among ORI-NS strains, 35% were MSSA (MICs 0.5-4 mg/L), mainly belonging to ST8, while 30% were MRSA (MICs 0.25-0.5 mg/L), mainly belonging to ST8 and 228.

The comparison between ComASP Oritavancin and the BMD reference method for all S. aureus tested demonstrated a CA of 97.5% and an EA of 100% (fig.1B).

Conclusions:

The ComASP Oritavancin system was developed to perform the BMD method for AST as recommended by international standards (CLSI; EUCAST). Our results obtained by comparing the ComASP Oritavancin system with the BMD reference method confirmed the reliability to test oritavancin susceptibility by Liofilchem panel. It is easy and rapid to use, and could contribute to reducing the turnaround for hospital laboratories.

Keyword(s): Oritavancin, Compact Antimicrobial Susceptibility Panel, Gram-positive

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