Laboratory methods for monitoring resistance to methycillin of Staphylococcus of zoonotic origin

Abstract

The development of antibiotic resistance in microorganisms is considered a modern phenomenon, which is usually caused by empirical antibiotic therapy. One of the representatives with high antibiotic resistance is staphylococcus aureus.Staphylococcus aureus is a pathogen resistant to broad-spectrum antibiotics and is responsible for most nosocomial infections. This microorganism synthesizes penicillinase, an enzyme that breaks down penicillin molecules. To effectively combat Staphylococcus aureus, a modified penicillin, methicillin, was previously used, the molecule of which was not destroyed by this enzyme. However, methicillin-resistant strains of this pathogen are also known today.As part of the group of methicillin-resistant staphylococci (MRSA), there are three subgroups: nosocomial variants of MRSA, community-acquired MRSA, MRSA associated with farm animals, common among farm animals (livestockassociated MRSA, LA-MRSA). MRSA are characterized by multidrug resistance.It was previously believed that Staphylococcus intermedius is the most dangerous staphylococcus for pets. However, over the past few years it has been found that the most common is Staphylococcus pseudintermedius, which is gaining increasing relevance. Staphylococcus pseudintermedius (MRSP) is a bacterium commonly found on the skin, mouth, nasal mucosa, and gastrointestinal tract in approximately 50% of pets. Unlike MRSA, MRSP is much more common in dogs and cats. One of the main methods of laboratory control over their spread is a monitoring study of the epizootic and epidemiological situation among animals and the population.The home environment plays a major role in the transmission of MRSA and MRSP, therefore, by taking careful measures to prevent the spread of infection, the likelihood of infection in both companion animals and humans can be reduced.The determination of sensitivity and resistance by phenotypic methods is carried out using: disk diffusion method, broth microdilution method, agar dilution method, E-test method.Laboratory methods for monitoring the mechanisms of resistance of staphylococci to methicillin include phenotypic methods using disks with oxacillin, or cefoxitin.Genotypic methods using polymerase chain reaction allow detecting the mecA, mecC gene.For a serological diagnostic method, a latex agglutination test is used to identify MRSA and MSSA (PSB2a / PSB2 spicelin-binding protein).Treatment of animals requires special attention because infections caused by multi-resistant staphylococci are more severe, chronic or latent, which increases the duration of treatment.