aureus to characterize it as persistent during mastitis may be a solution in provide the barcode that can be used to track and identify strains with the same or similar polymorphisms, and thus increase the chances of providing a treatment appropriate antimicrobial. aureus mastitis, and antimicrobial resistance is considered one of the reasons for low cure rates 16.Ĭonsequently, identifying the nuclear polymorphisms of S. Therefore, despite the best possible antimicrobial treatment, failures of bacteriological cure can often occur in mastitis treatments, especially for S. Enrofloxacin is a fluoroquinolone exclusively developed for use in veterinary medicine 13 and presents itself as an appropriate choice in some cases of mastitis in goats 14, being active against major pathogenic bacteria (both Gram-positive and Gram-negative) 15. Persistent mastitis in ruminants 11, 12 raises concerns because it renders ineffective treatments with antibiotics such as enrofloxacin 12. Persistent infections are typically multifactorial and may have mechanisms for different classes of antibiotics, such as β-lactams and fluoroquinolones 10, and mainly occurs due to the selection of different pathogens capable of evading the immune system 5, which are genetically prepared to activate the series of stress responses for long-term survival 4. In chronic goat’s mastitis cases, the mammary gland can atrophy due to severe damage to the glandular tissue leading to fibrosis and total loss of the ability to produce milk 9 and can result in the disposal of the animal. This type of persistent infection could also be identified in the types of mastitis, but it is often just referred to as chronic 8, and not as an antimicrobial persistence, which can results in the cure failure due to the performance of only the exchange of the antimicrobial, and consequently in premature culling or replacement of incurable animals. However, it can cause subclinical, clinical, persistent, gangrenous and difficult-to-treat intramammary infections 7. This bacterial agent is one of the most commonly found pathogens in clinical mastitis in several livestock species 1, such as goats 6. aureus is part of a small group of bacteria that can be named as 'persisters' in some diseases 4, since administration of antibiotic treatments based on correct protocols allows the survival of a distinct form of bacterial subpopulation in an infection 5. It appears on the world stage as a challenge in disease chronicity and persistence in antimicrobial treatments 2, 3. Staphylococcus aureus is a major opportunistic pathogen in humans and one of the most important pathogenic Staphylococcus species in veterinary medicine 1. This study may help in the future to identify and discriminate this agent in cases of mastitis, and with that, the most appropriate antibiotic treatment can be performed in advance of the appearance of persistent mastitis caused by the agent, reducing the chances of premature culling and animal suffering. aureus isolated from milk of goats diagnosed with persistent mastitis after the failed treatment with the antibiotic enrofloxacin. Therefore, this study identified genetic polymorphisms characteristic of S. In addition, the sequences ES-GPM to the arc gene and glpF alleles showed the greatest number of mutations for ES-GPM in relation to non-ES-GPM. The genetic diversity of some alleles showed be greater diversity and polymorphism than others, such as of the aroE and yqiL genes less than glpF gene. The 43 strains comprised 22 clonal complexes (CCs), of which the ES-GPM strains were present in CC133, CC5 and a new complex formed by the sequence type 4966. These two lineages were separated by 27 nuclear polymorphisms. The most strains of ES-GPM were categorically different phylogenetically from the others and could be divided into two lineages: one with a majority belonging to ES-GPM and the other to varied strains. aureus (ES-GPM) isolated from goats with persistent mastitis (GPM). Using the multilocus sequence typing technique, network approaches and study of the population diversity of microorganisms, we performed analyzes of S. Staphylococcus aureus is one of the main bacterial agents responsible for cases of mastitis in ruminants, playing an important role in the persistence and chronicity of diseases treated with antimicrobials.
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