No abstract

Chronic otitis externa of dogs is a significant problem due to the prevalence and complexity of the treatment of such animals. There is evidence that in 60–80% of cases of infectious diseases microorganisms located in the biofilm phenotype play the main role. Microorganisms in the biofilm phenotype have a number of advantages, the most significant of which is considered to be increased resistance to various external factors. Among them, a special place is occupied by resistance to antibiotics. In recent decades, research has been conducted at an increasing scale on the role of biofilm infections in various pathologies in veterinary medicine. The etiology and therapy of dog otitis externa caused by Malassezia pachydermatis biofilm has not been fully studied. This is why we consider relevant the scientific and practical aspects of research on the etiology and therapy of dog otitis externa from the position of biofilm infection. In this work, it has been statistically proven that there is a relationship between the optical density of Malassezia pachydermatis biofilms and their sensitivity to drugs, and this relationship is statistically significant. In addition, we have demonstrated that Farnesol has a good antibiofilm effect at a concentration of more 1.6 μM/mL (24% OD decrease of biofilm), and its highest antibiofilm effect (71–55%—more than a half) was observed at a concentration of 200–12.5 μM/mL.

No abstract

Caves are considered as ecosystems isolated from the surface in varying degrees. Hypogean habitats are mostly oligotrophic, with discretely distributed nutrients, where chemolithoautotrophic species can be found among the producers. In this case, vital activity is provided due to the nutrients of endogenous genesis. Of particular interest are the cavities, which were completely isolated from the surface impact for a long time. As a consequence, unique landscapes and mineral environments were formed in such cavities. An example is given by Taurida Cave, located on the Crimean Peninsula (Piedmont Crimea) and discovered during the construction of Taurida Highway. Samples of sediments were taken right after opening the cave in July 2018. For the cultivation of bacteria andmicrofungi, standard media, extracts from substrates were used. The number and biomass of microorganisms were determined by luminescence microscopy. Chemical composition of the main and trace elements of the cave deposits samples was determined by XRF WDS spectrometer. As a result, a difference in the number and biomass of microorganisms in different parts of the cave was revealed. The main contribution to the biomass of microorganisms is made by actinomycetes and microfungi. The bacteria were dominated by gram-positive bacteria of the genera Bacillus, Arthrobacter, Micrococcus. Among actinomycetes, species of the genus Streptomyces predominated. The species of microfungi Penicillium chrysogenum, Trichoderma sp., Aspergillus sp. were identified, Penicillium janczewskii dominated. The high abundance and biomass of microorganisms in the substrates of the cave may be related to the summer sampling period.