Phagocyte Activity in Response to Exposure to Methicillin-Resistant Staphylococcus aureus Strains

Abstract

The research focuses on the study of phagocyte activity of blood neutrophilic granulocytes, monocytes, and eosinophils under the exposure to methicillin-resistant strains of Staphylococcus aureus bacteria. The subjects of the research were represented by blood neutrophilic granulocytes, monocytes, and eosinophils, isolated from healthy people, as well as methicillin-resistant and methicillin-sensitive S.aureus bacteria strains (MRSA and MSSA). Phagocytosis functions (phagocytic number and phagocytic index) were estimated by FITC-labeled bacteria. The analysis of stained cells was performed using FC-500 flow cytofluorimeter (Beckman Coulter, USA) for whole peripheral blood. Phagocytosis research resulted in the following findings. In response to MRSA, the percentage of neutrophils involved in phagocytosis and average number of bacteria being present inside the cells increase as compared to those within sensitive strains. In response to MRSA exposure, the phagocytic index is higher in monocytes with CD14+CD16¯phenotype. At the same time, phagocytic number is higher in non-classic populations of monocytes CD14+CD16+and CD14^lowCD16+. Moreover, it should be noted that the classical type of monocytes CD14+CD16¯tends to be activated faster in regard to MRSA, but phagocytosis efficiency is lowered. Blood eosinophils also actively respond to MRSA. Thus, changes in functional activity of neutrophilic granulocytes, monocytes, and eosinophils in peripheral blood were established during MRSA induction. The bacterial receptor apparatus changes due to the modification of cellular wall as a result of acquired resistance to antibiotics.