Related Experiment Video

Updated: Jan 29, 2026

A Reference Broth Microdilution Method for Dalbavancin In Vitro Susceptibility Testing of Bacteria that Grow Aerobically
11:28

A Reference Broth Microdilution Method for Dalbavancin In Vitro Susceptibility Testing of Bacteria that Grow Aerobically

Published on: September 9, 2015

29.8K

In vitro activity of oritavancin alone or in combination against vancomycin-susceptible and -resistant enterococci

T Wu1, K Meyer1, A T Harrington2

  • 1College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA.

The Journal of Antimicrobial Chemotherapy
|February 13, 2019
PubMed
Abstract

Insights

Oritavancin showed limited synergy with other antibiotics against vancomycin-resistant enterococci (VRE) in vitro. Combination therapy with oritavancin is not routinely supported for VRE infections based on these findings.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Optimal treatment for serious Enterococcus spp. infections remains unclear.
  • Combination antimicrobial therapy is often recommended for invasive infections to improve outcomes.
  • Oritavancin is a lipoglycopeptide with activity against enterococci, but combination data are limited.

Purpose of the Study:

  • To evaluate the in vitro activity of oritavancin alone and in combination with other agents against vancomycin-susceptible and -resistant enterococci.
  • To assess the bactericidal activity and potential synergy of oritavancin combinations.
  • To inform treatment strategies for enterococcal infections.

Main Methods:

  • Time-kill analyses were performed using five enterococcal strains (three VRE E. faecium, one VRE E. faecium ATCC, one VSE E. faecalis ATCC).
  • Individual drugs were tested at various concentrations (¼, ½, 1, 2, 4× MIC).
  • Oritavancin combination experiments used agents at ¼× MIC.

Main Results:

  • Daptomycin was the most potent single agent, exhibiting bactericidal activity against all strains.
  • Oritavancin was bactericidal against clinical VRE strains at ≥2× MIC.
  • Oritavancin showed synergy with gentamicin against VRE strains lacking high-level aminoglycoside resistance; antagonism was noted in other combinations.

Conclusions:

  • In vitro data do not support routine combination therapy with oritavancin for vancomycin-resistant enterococci (VRE) infections.
  • Further research may be needed to identify specific scenarios where oritavancin combinations are beneficial.
  • Oritavancin's role in combination therapy for enterococcal infections requires further investigation.

More Related Videos

Modeling Chemotherapy Resistant Leukemia In Vitro08:41

Modeling Chemotherapy Resistant Leukemia In Vitro

Published on: February 9, 2016

9.6K
A Novel Method to Determine the Longitudinal Antibacterial Activity of Drug-Eluting Materials06:18

A Novel Method to Determine the Longitudinal Antibacterial Activity of Drug-Eluting Materials

Published on: March 3, 2023

1.8K

Related Concept Videos

Magnetic Susceptibility and Permeability01:31

Magnetic Susceptibility and Permeability

In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
2.4K
Susceptibility, Permittivity and Dielectric Constant01:26

Susceptibility, Permittivity and Dielectric Constant

When placed in an external electric field, a dielectric material gets polarized. The charge density in the dielectric material is given by the sum of the bound and free charge densities, while the total charge density can also be written in terms of the total electric field. The bound charge density can be measured in terms of polarization, leading to the relationship between electric displacement and polarization.
2.8K
Resistivity01:22

Resistivity

When a voltage is applied to a conductor, an electrical field is generated, and charges in the conductor feel the force due to the electrical field. The current density that results depends on the electrical field and the properties of the material. In some materials, including metals at a given temperature, the current density is approximately proportional to the electrical field. In these cases, the current density can be modeled as:
4.5K
Resistance01:19

Resistance

When a current moves through any conductor, the conductor causes some level of difficulty for the current to flow. The measure of that difficulty is known as the resistance of the material and is represented by R. Every material has its own resistance. In the case of conductors, heat is emitted whenever a current passes through them. Resistance depends on the resistivity of the material. Resistivity is a characteristic of the material used to fabricate electrical components, whereas the...
6.0K
Equivalent Resistance01:16

Equivalent Resistance

In circuit analysis, situations often arise where resistors are neither in series nor parallel configurations. To tackle such scenarios, three-terminal equivalent networks like the wye (Y) (Figure 1 (a)) or tee (T) and delta (Δ) (Figure 1 (b)) or pi (π) networks come into play. These networks offer versatile solutions and are frequently encountered in various applications, including three-phase electrical systems, electrical filters, and matching networks.
977
Resistance and Conductance01:25

Resistance and Conductance

A conductor's DC resistance at a given temperature is influenced by its resistivity, length, and cross-sectional area. Resistivity is an inherent property of the conductor material, with annealed copper serving as the international standard for measurement. For instance, the resistivity of hard-drawn aluminum at 20 degrees Celsius is 61% of the standard conductivity of annealed copper.
Various factors impact the resistance of a conductor. Spiraling in stranded conductors increases their...
509