Final answer:
Most musculoskeletal infections like osteomyelitis originate from bacteria such as Staphylococcus aureus which can enter the bone via trauma, surgery, or another infected site in the bloodstream, especially in adults, or by hematogenous spread in children.
Step-by-step explanation:
Most musculoskeletal infections, such as osteomyelitis or abscess, originate from a variety of different bacteria that gain access to the bone tissues through different routes. The most common causative agent of osteomyelitis and septic arthritis is Staphylococcus aureus (S. aureus). In adults, bacteria usually enter the bone through trauma, surgical procedures, prosthetic joint replacements, or from another infected site via the bloodstream. In children, the spread is often hematogenous, meaning that bacteria are introduced from the bloodstream, potentially from focal infections. In addition, opportunistic pathogens, including MRSA, can cause infections if they breach protective barriers and are introduced to other parts of the body where they can proliferate, such as during surgeries or through wounds.