Related Experiment Video
Updated: Sep 13, 2025
11:28
A Reference Broth Microdilution Method for Dalbavancin In Vitro Susceptibility Testing of Bacteria that Grow Aerobically
Published on: September 9, 2015
29.1K
Paradoxical interaction between dalbavancin and β-lactams against endocarditis-associated Enterococcus faecalis
David Luque Paz1,2, Adrien Turban2,3, François Guérin2,3,4
1Infectious Diseases Department, Pontchaillou University Hospital, Rennes, France.
The Journal of Antimicrobial Chemotherapy
|July 28, 2025
Summary
Dalbavancin shows poor activity against Enterococcus faecalis and can reduce the effectiveness of beta-lactams like amoxicillin. Caution is advised when using dalbavancin for E. faecalis infections, particularly endocarditis.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Limited in vitro studies exist on dalbavancin synergy with enterococci.
- Enterococcus faecalis is a significant pathogen, often requiring combination therapy.
Purpose of the Study:
- To evaluate the in vitro activity of dalbavancin against E. faecalis.
- To investigate the interaction between dalbavancin and beta-lactam antibiotics.
Main Methods:
- Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) determination.
- Checkerboard assays for initial interaction screening.
- Time-kill (TK) assays to confirm synergy or antagonism with beta-lactams.
Main Results:
- E. faecalis strains demonstrated tolerance to dalbavancin (MBC/MIC >32).
- Synergy was observed between dalbavancin and beta-lactams at sub-inhibitory concentrations in TK assays.
- Antagonism was noted when dalbavancin was combined with amoxicillin, ceftobiprole, or ertapenem at higher concentrations, significantly reducing bacterial killing compared to beta-lactams alone.
Conclusions:
- Dalbavancin exhibits limited efficacy against E. faecalis.
- Dalbavancin can impair the activity of beta-lactams, notably amoxicillin.
- Clinical use of dalbavancin for E. faecalis infective endocarditis warrants caution due to potential antagonistic effects.
Related Concept Videos
01:18Endocarditis III: Medical Management
19
Infective endocarditis management involves a multifaceted approach encompassing infection prevention, lifestyle modifications, pharmacological therapy, and surgical management.Infection Prevention:Hand Hygiene: Thorough handwashing is crucial to prevent the spread of infection. Hand hygiene should be performed regularly, especially before and after using the restroom.Oral Hygiene: Good oral hygiene is essential. It includes brushing teeth immediately after waking up and before bed, flossing...
19
01:27Combined Effects of Drugs: Synergism
4.8K
Synergism is a useful mechanism where combining two or more drugs is more effective than each constituent used alone. Such combinations are also called supra-additive interactions. The drugs collectively enhance the final therapeutic effect by acting on different targets. Another advantage is that the low dose of each constituent drug is sufficient to achieve the desired effect. This helps reduce the duration of therapy and lower the adverse effects of these drugs.
Such synergistic combinations...
Such synergistic combinations...
4.8K
01:25Endocarditis II: Clinical Features of Infective Endocarditis
25
Endocarditis can present various clinical features depending on the causative organism and the patient's underlying health conditions. Initially, the clinical features of infective endocarditis develop gradually, presenting with nonspecific symptoms that can be easily mistaken for other illnesses.General SymptomsEarly symptoms of infective endocarditis are fever, chills, weakness, malaise, fatigue, and weight loss. These symptoms reflect the systemic nature of the infection and the body's...
25
01:29Endocarditis IV: Nursing Management
31
Infective endocarditis (IE) is a chronic infection of the heart's endocardium, primarily affecting the heart valves. A detailed nursing assessment for a patient with IE involves collecting subjective and objective data to ensure an accurate diagnosis and timely intervention.Subjective DataThe nurse gathers information about the patient's symptoms and complaints during the subjective assessment. Patients with infective endocarditis often report non-specific symptoms that can mimic other...
31
01:25Endocarditis I: Introduction
26
Introduction:Endocarditis is the infection of the endocardium, the inner lining of the heart and its valves. When the heart muscle is involved, the condition is termed myocarditis, while an infection of the outer lining is called pericarditis. Infective endocarditis (IE) primarily affects the endocardium, where pathogens adhere to the valves or lining, forming vegetation that can lead to severe complications. Infective endocarditis occurs when microorganisms, usually bacteria from other body...
26
01:28Antimicrobial Effectiveness
163
The effectiveness of antimicrobial agents depends on various factors influencing their ability to eliminate microbial populations. Larger microbial populations require more time for complete eradication, emphasizing the importance of population size analysis when evaluating antimicrobial efficacy.Microbial resistance to antimicrobial agents varies significantly. Highly resilient microorganisms include endospores, gram-negative bacteria, and non-enveloped viruses, while prions are exceptionally...
163