Effects of adjunctive treatment with combined cytokines in a neutropenic mouse model of multidrug-resistant Enterococcus faecalis septicemia.

STUDY OBJECTIVE

To examine whether the antienterococcal efficacy of a regimen of gentamicin plus vancomycin combined with granulocyte colony-stimulating factor (G-CSF) is enhanced by concurrent therapy with interferon-gamma (IFN-gamma).

SETTING

Hospital laboratory.

INTERVENTION

Mice rendered neutropenic by cyclophosphamide were intraperitoneally inoculated with a gentamicin- and vancomycin-resistant Enterococcus faecalis isolate.

MEASUREMENTS AND MAIN RESULTS

Infected animals were randomized into treatment groups that received G-CSF alone or in combination with various dosages of IFN-gamma. Additional groups of animals received vancomycin; G-CSF, G-CSF plus vancomycin, IFN-gamma, and G-CSF; or vancomycin with both cytokines. Addition of IFN-gamma to G-CSF regimen resulted in no significant change (p>0.05) in survival, compared with treatment with G-CSF alone. Also, the antienterococcal efficacy of antibiotic plus G-CSF was not modified by coadministration of IFN-gamma.

CONCLUSION

This study suggests that adjunctive application of combined cytokines may not be more beneficial than only G-CSF in combination with an antibiotic to treat multidrug-resistant enterococcal infection.