Staphylococcus aureus exhibit similarities in their interactions with Acanthamoeba and ThP1 macrophage-like cells

Area of Science:

• Microbiology
• Pathogen Interactions
• Cell Biology

Background:

• Staphylococcus aureus is a major cause of hospital-acquired infections.
• The survival mechanisms of S. aureus against host immune cells like macrophages are not fully understood.
• Acanthamoeba, a protozoan, shares similarities with macrophages, suggesting potential parallels in pathogen interaction.

Purpose of the Study:

• To investigate the interactions between Staphylococcus aureus (both MSSA and MRSA) and Acanthamoeba castellanii.
• To compare these interactions with those between S. aureus and ThP1 macrophage-like cells.
• To determine if Acanthamoeba can serve as a host for S. aureus survival and dissemination.

Main Methods:

• Comparative study of methicillin-sensitive S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), and Staphylococcus epidermidis (SE) with Acanthamoeba castellanii (T4 genotype) and ThP1 macrophage-like cells.
• Assessment of bacterial binding, invasion, and intracellular survival within both Acanthamoeba and ThP1 cells.
• Investigation of bacterial survival within Acanthamoeba during the encystment process.

Main Results:

• Both MRSA and MSSA demonstrated similar binding, association, and invasion patterns with A. castellanii and ThP1 cells.
• Intracellular survival of MRSA and MSSA was observed within both Acanthamoeba and ThP1 cells upon long-term incubation.
• Bacteria were recovered from mature Acanthamoeba cysts, indicating survival during the encystment phase.

Conclusions:

• Acanthamoeba exhibits characteristics similar to macrophage-like cells in its interaction with S. aureus.
• Acanthamoeba can host intracellular S. aureus, including during encystment.
• Airborne Acanthamoeba cysts may function as 'Trojan horses' for the dissemination of S. aureus to susceptible hosts.