hylococcus aureus (including methicillin-resistant isolates)
Streptococcus pyogenes
Streptococcus agalactiae
Streptococcus anginosus group (including S. anginosus, S. intermedius, S. constellatus)
The following in vitro data are available, but their clinical significance is unknown. In addition, at least 90% of organisms in the following bacteria exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the dalbavancin susceptible breakpoint of 0.12 mcg/mL. However, the safety and efficacy of dalbavancin in treating clinical infections due to these bacteria have not been established in adequate well-controlled clinical trials.
Gram-positive bacteria
Enterococcus faecium (vancomycin-susceptible isolates only)
Enterococcus faecalis (vancomycin-susceptible isolates only)
Susceptibility Test Methods
When available, the clinical microbiology laboratory should provide the results of in vitro susceptibility test results for antimicrobial drug products used in resident hospitals to the physician as periodic reports that describe the susceptibility profile of nosocomial and community-acquired pathogens. These reports should aid the physician in selecting an antibacterial drug for treatment.
Dilution Techniques
Quantitative methods are used to determine minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized test method.1,2 When determining dalbavancin MICs, polysorbate-80 (P-80), should be added at a final concentration of 0.002% to freshly prepared or frozen microtiter trays. The MIC values should be interpreted according to the criteria provided in Table 4.
Diffusion Techniques
Dalbavancin disks for diffusion susceptibility testing are not available. Disk diffusion is not a reliable method for determining the in vitro activity of dalbavancin.
Table 4. Susceptibility Test Interpretive Criteria for Dalbavancin Pathogen
MIC (mcg/mL)a Zone Diameter (mm)
S
I
R
S
I
R
Staphylococcus aureus
(including methicillin-resistant isolates)
≤ 0.12
--
--
--
--
--
Streptococcus pyogenes,
Streptococcus agalactiae, and
Streptococcus anginosus group
≤ 0.12
--
--
--
--
--
a The current absence of data on resistant isolates precludes defining any category other than "Susceptible". If isolates yield MIC results other than susceptible, they should be submitted to a reference laboratory for additional testing.
A report of "Susceptible" indicates that the antibacterial agent is likely to inhibit growth of the pathogen if the antibacterial compound reaches the concentrations at the infection site necessary to inhibit growth of the pathogen.
Quality Control
Standardized susceptibility test procedures require the use of laboratory controls to monitor and ensure the accuracy and precision of supplies and reagents used in the assay, and the techniques of the individuals performing the test.1, 2 Standard dalbavancin powder should provide the following range of MIC values noted in Table 5.
Table 5. Acceptable MIC Quality Control Range |
