**5. Antimicrobial activity of other honeybee products**

In addition, honeybees also produce propolis, wax, pollen, bee bread and royal jelly. All these products exhibit some antibacterial activity. However, from the point of view of possibilities of their application for prophylaxis or treatment of infections, definitely the most promising is propolis. It is a resinous substance produced from plants' buds and exudates, modified by addition of honeybees' salivary secretions and wax. It is a product of a very complex chemical composition, which depends on many factors; in particular, important are geographical location and plant base, which is available for honeybees when collecting their products. Some of its ingredients, mainly polyphenols and flavonoids, exhibit high antimicrobial activity. As a consequence, it is used by honeybees as a hive disinfectant [40]. Ethanolic extracts of propolis exhibit high activity against wide spectrum of human and veterinary pathogenic microorganisms. The investigation carried out in our group revealed promising activity of Polish propolis against clinical isolates of azole-resistant yeasts of the genus *Candida*. In total susceptibility of 44 strains [*C. albicans* (*n* = 20), *C. glabrata* (*n* = 14) and *C. krusei* (*n* = 10)] were tested, and in the case of one sample of propolis, the MFC (*Minimal Fungicidal Concentration*) values were in range from 0.156 to 1.25% (v/v) [41]. Many studies also revealed high activity of propolis against Gram-positive bacteria, including as dangerous pathogens as *S. aureus, S. epidermidis, Listeria monocytogenes* [42], *Bacillus subtilis* and *B. cereus* [43]. It has been also confirmed that ethanolic extracts of propolis enhance activity of some antibiotics against staphylococci [44]. Some important Gram-negative bacteria also exhibit sensitivity to the components of propolis. However, the research of propolis from different regions of the world is consistent and indicates that higher concentrations are necessary for elimination of *E. coli* or *P. aeruginosa* in comparison with Gram-positive bacteria [45–47]. Propolis belongs to the most popular products used for treatment infections in traditional medicine. During last several decades, its high antimicrobial potential has been confirmed with a large number of scientific publications. We have no doubts that possibilities of application of this product in clinical medicine deserve consideration.
