What is the primary use of tigecycline?

Tigecycline is primarily used for the treatment of complicated skin and soft tissue infections as well as intra-abdominal infections. This antibiotic belongs to the glycylcyclines class, which are structurally related to the tetracyclines and have a broad spectrum of activity against various Gram-positive and Gram-negative bacteria, including those that are resistant to other common antibiotics.

The effectiveness of tigecycline in these particular types of infections is attributed to its ability to penetrate tissues and its action against bacteria that might exhibit resistance to other antibiotics. It is often indicated for cases where traditional antibiotics may not work due to such resistance or in complicated scenarios where infections are polymicrobial.

Considering the context of the other options, it is important to note that tigecycline is not typically used as a single-dose treatment for urinary tract infections, as it has a limited urinary excretion profile, making it less effective for such indications. It also does not serve as prophylaxis against endocarditis or for viral infections, as its spectrum is geared towards bacterial pathogens. Thus, the correct option highlights its role in managing more complex, difficult-to-treat infections, aligning with its developed indications and characteristics.