Final answer:
The subject in question is a virus, which is not susceptible to antibiotics and can only be seen with an electron microscope due to its small size. Antibiotics target bacteria, not viruses, and the spread of antibiotic-resistant bacteria like MRSA is a significant concern in healthcare.
Step-by-step explanation:
The organism described in the question, not susceptible to antibiotics and only visible by an electron microscope, is likely a virus. Viruses are exceedingly small infectious agents that are observed using electron microscopy due to their size being beyond the resolution of standard light microscopes. They do not respond to antibiotics because these drugs are designed to target cellular organisms, specifically bacteria, and viruses lack the cell structures that antibiotics typically disrupt. In contrast, bacteria like Clostridium difficile are visible with electron microscopy and can sometimes become resistant to antibiotics, particularly after the normal gut microflora has been compromised by such drugs.
Addressing antibiotic resistance has become a critical aspect of modern medicine and research, as certain bacterial species, like methicillin-resistant S. aureus (MRSA), have evolved to fend off many commonly used antibiotics. Developing content loaded with new and diversified antibiotics, as well as strategies such as targeting bacterial virulence factors, are important steps in countering this issue.