Hyaluron-Based Bionanocomposites of Silver Nanoparticles with Graphene Oxide as Effective Growth Inhibitors of Wound-Derived Bacteria.

Keeping wounds clean in small animals is a big challenge, which is why they often become infected, creating a risk of transmission to animal owners. Therefore, it is crucial to search for new biocompatible materials that have the potential to be used in smart wound dressings with both wound healing and bacteriostatic properties to prevent infection. In our previous work, we obtained innovative hyaluronate matrix-based bionanocomposites containing nanosilver and nanosilver/graphene oxide (Hyal/Ag and Hyal/Ag/GO). This study aimed to thoroughly examine the bacteriostatic properties of foils containing the previously developed bionanocomposites. The bacteriostatic activity was assessed in vitro on 88 Gram-positive (n = 51) and Gram-negative (n = 37) bacteria isolated from wounds of small animals and whose antimicrobial resistance patterns and resistance mechanisms were examined in an earlier study. Here, 69.32% of bacterial growth was inhibited by Hyal/Ag and 81.82% by Hyal/Ag/GO. The bionanocomposites appeared more effective against Gram-negative bacteria (growth inhibition of 75.68% and 89.19% by Hyal/Ag and Hyal/Ag/Go, respectively). The effectiveness of Hyal/Ag/GO against Gram-positive bacteria was also high (inhibition of 80.39% of strains), while Hyal/Ag inhibited the growth of 64.71% of Gram-positive bacteria. The effectiveness of Hyal/Ag and Hyal/Ag/Go varied depending on bacterial genus and species. Proteus (Gram-negative) and Enterococcus (Gram-positive) appeared to be the least susceptible to the bionanocomposites. Hyal/Ag most effectively inhibited the growth of non-pathogenic Gram-positive Sporosarcina luteola and Gram-negative Acinetobacter. Hyal/Ag/GO was most effective against Gram-positive Streptococcus and Gram-negative Moraxella osloensis. The Hyal/Ag/GO bionanocomposites proved to be very promising new antibacterial, biocompatible materials that could be used in the production of bioactive wound dressings.

Wounds of Companion Animals as a Habitat of Antibiotic-Resistant Bacteria That Are Potentially Harmful to Humans-Phenotypic, Proteomic and Molecular Detection.

Skin wounds and their infections by antibiotic-resistant bacteria (ARB) are very common in small animals, posing the risk of acquiring ARB by pet owners or antibiotic resistance gene (ARG) transfer to the owners' microbiota. The aim of this study was to identify the most common pathogens infecting wounds of companion animals, assess their antibiotic resistance, and determine the ARGs using culture-based, molecular, and proteomic methods. A total of 136 bacterial strains were isolated from wound swabs. Their species was identified using chromogenic media, followed by MALDI-TOF spectrometry. Antibiotic resistance was tested using disc diffusion, and twelve ARGs were detected using PCRs. The dominant species included Staphylococcus pseudintermedius (9.56%), E. coli, and E. faecalis (both n = 11, 8.09%). Enterobacterales were mostly resistant to amoxicillin/clavulanic acid (68.3% strains), all Pseudomonas were resistant to ceftazidime, piperacillin/tazobactam, imipenem, and tylosin, Acinetobacter were mostly resistant to tylosin (55.5%), all Enterococcus were resistant to imipenem, and 39.2% of Staphylococci were resistant to clindamycin. Among ARGs, strA (streptomycin resistance), sul3 (sulfonamide resistance), and blaTEM, an extended-spectrum beta-lactamase determinant, were the most frequent. The risk of ARB and ARG transfer between animals and humans causes the need to search for new antimicrobial therapies in future veterinary medicine.

In Vitro Antibacterial Activity of Ozonated Olive Oil against Bacteria of Various Antimicrobial Resistance Profiles Isolated from Wounds of Companion Animals.

Frequent colonization and bacterial infection of skin wounds in small animals prevent or impair their healing. However, the broadly applied antimicrobial therapy of wounds is not always necessary and promotes the spread of bacterial resistance. Thus, alternatives to antimicrobial therapy, including preventive measures in the form of wound dressings with antibiotic properties, should be searched for. The aim of this study was to develop a new, efficient, cost-effective and non-toxic formulation with antimicrobial properties to serve as an alternative to antibiotic administration in wound-healing stimulation in companion animals. Nano/microencapsulated ozonated olive oil in a hyaluronan matrix was developed, with ozone concentration high enough to prevent bacterial growth. The presence and size of nano- and microcapsules were determined with scanning electron microscopy (SEM). Antibacterial activity of developed formulations was examined in vitro on 101 Gram-positive and Gram-negative bacteria isolated from the wounds of companion animals. The highest ozone concentration in the developed formulations inhibited the growth of 40.59% bacteria. Species and genus-specific differences in reactions were observed. Enterococcus spp. proved the least susceptible while non-pathogenic Gram-positive bacteria were the most susceptible to the examined formulations. Changes in the bacterial morphology and cell structure of Psychrobacter sanguinis suspension mixed with Ca-stabilized formulations with nano/microencapsulated ozonized olive oil were revealed during SEM observations. The combination of compounds that promote wound healing (hyaluronic acid, olive oil, ozone and calcium) with the antibacterial activity of the developed formula makes it a promising bionanocomposite for use as a topical dressing.

The use of stem cells in the treatment of mastitis in dairy cows.

Mastitis is a multifactorial inflammatory disease. The increase in antibiotic resistance of bacteria that cause mastitis means that cattle breeders would prefer to reduce the use of antibiotics. Recently, therapies using mesenchymal stem cells (MSCs) from various sources have gained significant interest in the development of regenerative medicine in humans and animals, due to their extraordinary range of properties and functions. The aim of this study was to analyze the effectiveness of an allogeneic stem cells derived from bone marrow (BMSC) and adipose tissue (ADSC) in treating mastitis in dairy cattle. The research material consisted of milk and blood samples collected from 39 Polish Holstein-Friesian cows, 36 of which were classified as having mastitis, based on cytological evaluation of their milk. The experimental group was divided into subgroups according to the method of MSC administration: intravenous, intramammary, and intravenous + intramammary, and according to the allogeneic stem cells administered: BMSC and ADSC. The research material was collected at several time intervals: before the administration of stem cells, after 24 and 72 h, and after 7 days. Blood samples were collected to assess hematological parameters and the level of pro-inflammatory cytokines, while the milk samples were used for microbiological assessment and to determine the somatic cells count (SCC). The administration of allogeneic MSCs resulted in a reduction in the total number of bacterial cells, Staphylococcus aureus, bacteria from the Enterobacteriaceae group, and a systematic decrease in SCC in milk. The therapeutic effect was achieved via intravenous + intramammary or intramammary administration.