Final answer:
Infections after prosthetic device implants are usually caused by pathogens that form biofilms on the device surface, which are highly resistant to antibiotics and the body's immune system, making them difficult to treat.
Step-by-step explanation:
Infections after prosthetic device implants are commonly produced by pathogens introduced during surgery, from other infected body sites via the bloodstream, or through trauma associated with the prosthetic joint replacement. These infections can occur when conditions favor the formation of biofilms on the surface of these devices. Biofilms are complex communities of microorganisms that adhere to surfaces and are enmeshed in a protective extracellular matrix, which makes them extremely resistant to antibiotics and host immune responses. Common pathogens that cause these infections include Staphylococcus aureus, which can attach to the layers of extracellular substrate and form a biofilm. Infections related to implants are challenging to treat due to biofilms' resistance to antibiotics and are often attributed to iatrogenic or nosocomial sources in medical settings.