Synercid has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections, as described in the INDICATIONS AND USAGE section.

Enterococcus faecium (Vancomycin-resistant and multi-drug resistant strains only)
Staphylococcus aureus (methicillin-susceptible strains only)
Streptococcus pyogenes

NOTE: Synercid is not active against Enterococcus faecalis. Differentiation of enterococcal species is important to avoid misidentification of Enterococcus faecalis as Enterococcus faecium.

The following in vitro data are available, but their clinical significance is unknown.

The combination of quinupristin and dalfopristin (Synercid) exhibits in vitro minimum inhibitory concentrations (MICs) of £1.0mg/mL against most ( ³90%) isolates of the following microorganisms; however, the safety and effectiveness of Synercid in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials.

Aerobic gram-positive microorganisms

Corynebacterium jeikeium
Staphylococcus aureus (methicillin-resistant strains)
Staphylococcus epidermidis (including methicillin-resistant strains)
Streptococcus agalactiae

SUSCEPTIBILITY TESTING

Dilution techniques

Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These M.C. provide estimates of the susceptibility of microorganisms to antimicrobial compounds. The M.C. should be determined using a standardized procedure. Standardized procedures are based on a dilution 1 method (broth or agar) or equivalent using standardized inoculum concentrations, and standardized concentrations of quinupristin/dalfopristin (Synercid) in a 30:70 ratio made from powder of known potency. The MIC values should be interpreted according to the following criteria:

^a. The interpretive values for Streptococcus spp. are applicable only to broth microdilution susceptibility testing using cation-adjusted Mueller-Hinton broth with 2 to 5% lysed horse blood.

A report of Susceptible indicates that the pathogen is likely to be inhibited if the concentration of the antimicrobial compound in the blood reaches usually achievable levels. A report of Intermediate indicates that the result should be considered equivocal, and if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category provides a buffer zone which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of Resistant indicates that the pathogen is not likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable; other therapy should be selected.

Bookmark this page: