Final answer:
Bacteria are the most common pathogens involved in health care-associated infections, often transmitted via medical devices or contributing to biofilms in plaque.
Step-by-step explanation:
The type of pathogen most often implicated in healthcare-associated infections is bacteria. Healthcare environments often have a high prevalence of bacteria due to the concentration of ill patients and invasive procedures that can compromise the body's natural barriers to infection. Bacteria can lead to various types of hospital-acquired infections, including those transmitted through medical devices like catheters or surgical sites. An example of bacteria associated with nosocomial infections transmitted via medical devices is Staphylococcus epidermidis. Furthermore, specific bacterial pathogens like Streptococcus mutans are known to contribute significantly to biofilms in plaque, which can lead to dental and other infections within a healthcare setting.