Determinación de la capacidad hemolítica en cepas de S. aureus resistentes a meticilina.

Abstract

Abstract: The hemolytic capacity of methicillin-resistant S. aureus (MRSA) strains primarily depends on proteins known as hemolysins. These proteins are responsible for lysing host cells, enabling the spread of infection throughout the body and evading the immune response. Hemolysins constitute part of the extensive array of virulence factors exhibited by the bacteria and are classified into alpha, beta, and gamma types. This study investigates the hemolytic capacity of a collection of MRSA bacterial strains isolated from the hands and nostrils of medical personnel at a public hospital in the city of Loja. A qualitative assessment of hemolytic patterns on sheep blood agar and a quantitative analysis using spectrophotometry absorbance measurements were employed. Qualitative analysis revealed that 37.5% (15/40) of the strains exhibited alpha hemolysis, 62.5% (25/40) exhibited beta hemolysis, and 0% (0/40) exhibited gamma hemolysis. Quantitative absorbance data were subjected to Variance analysis, indicating no significant difference in hemolytic capacity compared to controls, as evidenced by a p-value > 0.05. Additionally, a strong correlation was observed through analysis using the Correlation Coefficient between the absorbances of strains classified as alpha and beta hemolytic and their respective controls, S. pneumoniae and S. pyogenes, with the coefficient falling within the range of 0.50 &#8804; r < 1.00. In conclusion, the capacity to induce hemolysis is influenced by various factors, primarily the duration of incubation and the presence or absence of CO2 during incubation.