Pyoderma in dogs (classification, pathogenesis, main pathogens, treatment)

The skin is the largest immune organ and the first obstacle to the penetration of pathogenic microorganisms into the host's body. The surface of the animal's body is inhabited by many microbes that ensure the homeostasis of the covering tissues. Mutual cooperation between microbial inhabitants and host cells supports both morphological and functional properties of the skin. A characteristic feature of representatives of the skin microbiome is the ability to colonize, that is, the very support of the development of a certain population of bacteria for a long time in the absence of signs of skin disease. Many opportunistic microorganisms live on the surface of the skin, which under favorable conditions can become pathogenic if their excessive or uncontrolled reproduction. A number of authors refer to such microbes as: streptococci, staphylococci, dermatophyte fungi, and bacteria of the Escherichia coli group. Violation of the epithelial barrier and injuries, parasites, thermal exposure, irritation of an allergic or hormonal nature leads to inflammation of the skin – dermatitis. Depending on the cause, the following types of dermatitis are mainly distinguished: traumatic, contact, atopic, parasitic, allergic, fungal and bacterial. Usually, each of the mentioned dermatitis is aggravated by bacteria, and in case of existing skin lesions, it allows microorganisms to penetrate from the surface to the lower layers of the skin and cause a purulent bacterial infection – pyoderma. Pyoderma refers to factor diseases, that is, those that occur most often under certain conditions, which are systemic or local in nature. Such conditions can serve as: immunosuppressive conditions, the course of diseases of various etiology, which are characterized by skin damage, maceration and mechanical traumatization. According to the depth of skin damage, pyoderma is classified into superficial and deep. Among the skin commensals, staphylococci are the main causative agents of pyoderma. Staphylococci are normally present not only on the skin of animals, but are very widespread in nature and have evolved a high resistance to antimicrobial drugs. Resistance to antibiotics creates difficulties for veterinarians in providing care to sick animals. In general, the treatment of pyoderma is long-term and requires a complex approach: elimination of the causes of the disease, use of antimicrobial drugs with mandatory determination of the sensitivity of microorganisms to them, cleaning of the skin with the use of washing, external application of antiseptic drugs, as well as the use of anti-inflammatory and sedative drugs. Therefore, the only effective method of therapy, according to various authors, is the use of antibiotics to which the pathogen is sensitive. This leads to antibiotic resistance of the bacterial microflora. The emergence of resistance of pathogens to antimicrobial agents makes further treatment impossible. The analysis of literary data indicates that pyodermas in dogs occur most often under certain conditions, which can be skin diseases of various etiologies. Therefore, the work of scientists should be aimed at the development and implementation of therapeutic measures and means that would neutralize bacterial agents without causing them to become resistant to antibiotics. The article describes the mechanisms of infection and possible favorable factors that are the key to this process. Issues of approach and treatment of pyoderma and complications related to it are highlighted. On the basis of the received data, an analysis was carried out and a perspective vector was formed for the further direction of scientific research, which would allow to eliminate the problem of this disease.