Synergistic effect of haloduracin and chloramphenicol against clinically important Gram-positive bacteria.

The emergence of drug-resistant pathogens has triggered the search for more efficient antimicrobial agents and formulations for treatment of infections. In recent years, combination therapy has become one of the effective clinical practices in treating infections. The present study deals with the effect of haloduracin, a lantibiotic bateriocin and chloramphenicol against clinically important bacteria. The combined use of haloduracin and chloramphenicol resulted in remarkable synergy against a spectrum of microorganisms including strains of Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis and different groups of Streptococcus. The synergy allowed using these antimicrobial agents at substantially reduced concentrations without compromising their efficiency. Use of lower doses of chloramphenicol can avoid the severity of its side effects. In addition to minimizing undesirable side effects of some drugs, this approach brings the possibility of using antibiotics that are no longer effective due to drug resistance. Furthermore, the observed synergy between haloduracin and chloramphenicol opens a new window of using bacteriocins and antibiotics in combination therapy of infections.