Quinupristin is primarily used in combination with dalfopristin to treat severe bacterial infections caused by Gram-positive organisms, particularly those resistant to other antibiotics. It is effective against infections like skin and soft tissue infections, pneumonia, and those caused by methicillin-resistant Staphylococcus aureus (MRSA). The combination works by inhibiting bacterial protein synthesis, making it a valuable option in hospitals for managing complicated infections where other treatments have failed. It is typically administered intravenously in a clinical setting under medical supervision.