| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1186-1 | ||||
Resumo:Milk has been present in the human diet for decades due to its high-level nutritional composition. However, as a beverage rich in energy, it can serve as an excellent medium for the proliferation of pathogenic bacteria, among well-known bacterium associated with foodborne diseases is Staphylococcus aureus. This bacterium is capable of developing several virulence factors and mechanisms of resistance to different drugs, particularly when exposed to subinhibitory concentrations. The development of multidrug resistance has led to the emergence of different species, such as Methicillin-Resistant S. aureus (MRSA), which has become a significant concern in public health settings due to its impact on patient mortality rates in hospitals. In this context, the objective of this research was to identify the resistance profile of S. aureus isolated from fresh milk commercialized around public market of Sobral-CE. For isolation, a 1mL of fresh milk was enriched in Tryptone Soy Broth (TSB) and incubated for 24 h at 37º C. The resulting inoculum was then plated on Baird Parker culture medium and subjected to the same conditions as before. Strains were identified presumptively using Gram staining and by testing for the production of enzymes, specifically peroxidases and hemolysins. The resistance profile was evaluated by the disk-diffusion method against following antibiotics panel, ampicillin (AMP), imipenem (IPM), norfloxacin (NOR), gentamicin (GEN), erythromycin (ERI), tetracycline (TET), linezolid (LNZ) and rifampicin (RIF). Presumptive screening for MRSA was explored using microdilution with oxacillin (OXA) and disk-diffusion with cefoxitin (CFO). The diameter of the zone of inhibition was used to determine sensitivity or resistance, based on recommendations from the Brazilian Committee for Antimicrobial Sensitivity Testing - BrCAST. The results showed 39 strains were presumptively isolated from the milk samples. Among these, 15 presented α-hemolysis, 8 β-hemolysis, and 16 γ-hemolysis. The phenotypic resistance testing indicated that 77% (30/39) of the strains were resistant to at least one antimicrobial, and 32% (12/39) of the strains were resistant more than three antibiotic classes, characterizing multidrug resistant (MDR) profile. The antimicrobials that showed the highest resistance rates were AMP (43.58%) and ERI (41.02%). Regarding MRSA screening using OXA and CFO to detect the expression of mecA and mecC genes, 6 strains (15.38% (6/39) tested positive. In conclusion, the research highlights that milk provides a favorable environment for the growth and proliferation of pathogenic microorganisms, including MDR strains. This emphasizes the importance of proper antimicrobial use and monitoring in dairy animals to prevent the dissemination of MDR bacteria through milk consumption. Palavras-chave: Antibiotic, dairy products, methicillin-resistant S. aureus, multidrug-resistant Agência de fomento:Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico (FUNCAP) | |||||