Final answer:
The microorganism that causes difficult-to-treat infections in medical devices due to biofilm formation and antibiotic resistance is Staphylococcus aureus (option 2). This bacteria is especially problematic in the form of MRSA, which can cause serious infections in various parts of the body.
Step-by-step explanation:
It may be difficult to treat infections of the microorganisms that have colonized medical devices in a body, in part because they are more resistant to antibiotics when they are attached to a surface. The correct answer to this question is Staphylococcus aureus (option 2).
Staphylococcus aureus is known to form biofilms on the surfaces of medical devices such as catheters. These biofilms can be highly resistant to antibiotics, making the infections they cause difficult to treat. Methicillin-resistant Staphylococcus aureus (MRSA) is a particularly dangerous strain due to its high level of resistance to commonly used antibiotics. Among healthcare-associated infections, MRSA has become a significant problem as it can also infect the bloodstream, lungs, urinary tract, or injury sites.
To directly address part 6 of the reference question, the species frequently associated with nosocomial infections transmitted via medical devices inserted into the body is Staphylococcus epidermidis, which is well-known for its ability to form biofilms on the surfaces of medical devices. However, in the context of antibiotic resistance and the ability to cause serious complications, Staphylococcus aureus is a major concern.