Why are opportunistic pathogens that form biofilms on indwelling devices particularly difficult to eradicate and a common cause of device-associated HAIs?

• A. Biofilm-forming bacteria are inherently unable to adhere to device surfaces and therefore are an unlikely source of infection, making device-associated HAIs mostly a myth.
• B. Because biofilms make bacteria grow faster and be more visible to cleaning staff, they are easy to identify and therefore rarely cause persistent infections.
• C. Biofilms only form in soil and environmental waters and never on medical devices because hospital materials repel microbes completely.
• D. Biofilms protect bacteria from disinfectants and antibiotics, reduce penetration of host immune effectors, and create a reservoir on device surfaces that continuously seeds infection, so standard surface cleaning is often insufficient without device removal or specific reprocessing.

Answer: (D)