Resistance Patterns of Staphylococcus aureus 700698 to Various Stress Conditions and Pathogenicity Profiles on HEp–2 cell Lines

Leonard L. Williams; Bernice D. Karlton–Senaye; Vamsi K. Vasireddy; Jacqueline U. Johnson

Volume : VII, Issue : VII, July - 2017

Resistance Patterns of Staphylococcus aureus 700698 to Various Stress Conditions and Pathogenicity Profiles on HEp–2 cell Lines

Leonard L. Williams, Bernice D. Karlton Senaye, Vamsi K. Vasireddy, Jacqueline U. Johnson

Abstract :

Staphylococcus aureus (S.aureus) is a major pathogen causing life threatening diseases worldwide. In vitro, it has been shown to acquire resistance towards various stresses and adhere and invade various host cells. This study examined the resistance patterns of S. aureus to various stresses and their pathogenicity profiles in absence of fionectin in host cells. S. aureus 700698 was subjected to various stresses (heat, cold, acid, hydrogen peroxide and sodium chloride). Stress resistance was analyzed by quantifying the population reduction and protein expression profiles by 2–D SDS–PAGE. HEp–2 cells were used for bacterial adhesion and internalization. Percentage of HEp–2 cell lysis was determined using released lactate dehydrogenase, and ability to induce apoptosis was analyzed by DNA fragmentation. Statistical analysis was performed on adhesion and internalization assays. Stress resistance was highest for heat (log₁₀ 0.14) and lowest for H₂O₂ (log₁₀2.6). Approximately 292 proteins were expressed by 2–D SDS–PAGE, having acidic proteins in higher ratio. Adhesion and invasion was significantly (p≤0.05) increased under H₂O₂(log₁₀ 6.49), acid (log₁₀ 5.46) and heat (log₁₀5.32) stresses, but numerically higher under Cold and NaCl stresses. Varying LDH profiles were observed in stress treatments, but after 24h, NaCl stress had the highest LDH release (34.8%) and lowest (18%) was observed in heat stressed bacteria. No apoptosis was observed in HEp–2 cells by DNA fragmentation and morphological changes. Further research on identifying proteins is required to understand host–microbe interactions of S. aureus. < clear="all" style="mso–special–character:line–eak;page–eak–before:always" />