Hospital Environments and Epidemiology of Healthcare-Associated Infections

Today, hospitals are facing difficult challenges: increasing proportion of immunologically vulnerable patients often affected by diseases requiring high complex level of healthcare; rapidly evolving medical technologies and healthcare models; and budget restrictions. All these features interfere with healthcare and can modify the risk of acquiring healthcare-associated infections (HCAIs). Therefore, HCAI prevention is a high priority for healthcare systems. Authors describe human and environmental origin of HCAIs, focusing on the modality of transmission of those airborne pathogens, including the new insight derived from the recent acquisitions about SARS and Ebola epidemiology. They also describe the state of the art about microorganism concentration (infective dose) required to determine a HCAI and the role played by other virulence factors. Finally, the effective control measures used for the prevention of airborne pathogen transmission are described, focusing mainly on the risk assessment and infection control.