Antibiofilm activity of honey against growth and biofilm formation ability of <i>Aerococcus viridans</i>

Honey is a potent antimicrobial agent. This study aimed to focus on the effect of two types of local honey (mountain and garden honey) on bacterial growth and its ability to produce biofilms. Six concentrations from each type of honey (1.56, 3.13, 6.25, 12.50, 25, and 50 % weight/volume w/v) were tested for this study. Using the microtiter plate method, six pathogenic strains, including Pseudomonas stutzeri, Acinetobacter baumanni, Burkholderia cepacia, Klebsiella oxytoca, Aerococcus viridans, and Staphylococcus aureus, were first examined for their ability to form biofilms. The Aerococcus viridans demonstrated the highest ability to form biofilms; therefore, it was chosen for further experiments. To obtain additional information, the isolate was identified using the 16S rRNA sequence, which produced 100% similarity with the 16S ribosomal RNA gene of Aerococcus viridans strain MT502756. The isolate was submitted in National Center for Biotechnology Information NCBI under the accession number PQ416042. The phylogenetic tree analysis of the strain revealed that it was most closely related to the Aerococcus viridans strain Rizhao 5111 (MN240427). The antibiotic susceptibility results, obtained using the disk diffusion method, showed that A. viridans was resistant to tetracycline, gentamicin, erythromycin, chloramphenicol, clindamycin, ceftriaxone, and ceftazidime. Both of honey showed an effect on the growth of A. viridans at concentrations of 12.5, 25, and 50%. Finally, the ability to shape biofilms was prevented at a 50% concentration when treated with mountain honey, while when using garden honey, it had stopped forming a biofilm at the 12.50%, 25%, and 50% concentrations.