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.