Biological properties and clinical application of propolis. III. Investigation of the sensitivity of Staphylococci isolated from pathological cases to ethanol extract of propolis (EEP). Attempts on inducing resistance in laboratory Staphylococcus strain to EEP.

Staphylococci isolated from pathological material exhibited a reduced sensitivity to ethanol extract of propolis (EEP) in 90% of cases. No cross-resistance of the staphylococci to EEP and to any commonly used antibiotics was found. The induction of resistance to EEP in laboratory strain of Staphylococcus aureus (Oxford 209 P) can be achieved already after serial passages on nutrient media containing EEP. Culturing Staphylococcus resistant to EEP in an environment devoid of this compound caused a remission to sensitivity of the strain investigated.