nosocomial

Nosocomial infections, more commonly known as hospital-acquired infections (HAIs), are infections contracted by patients during a hospital or other healthcare facility stay that were not present and were not incubating at the time of admission. They may develop during the stay or within a defined period after discharge, depending on the infection type. The term nosocomial originates from Greek nosos (disease) and komeion (to take care of).

Common sites and types include urinary tract infections, often related to catheter use; surgical site infections; pneumonia, including ventilator-associated pneumonia; and bloodstream infections, including catheter-associated bloodstream infections. Invasive devices such as urinary catheters and central venous catheters are major risk factors. Pathogens frequently involved include Staphylococcus aureus (including MRSA), coagulase-negative staphylococci, Enterococcus species, and Gram-negative bacteria such as Escherichia coli, Klebsiella, Pseudomonas, and Acinetobacter, as well as Candida species.

Transmission occurs through endogenous flora or exogenous sources, with poor hand hygiene, breaks in aseptic technique, and environmental contamination contributing to spread. Prevention focuses on hand hygiene, aseptic care and sterile technique for invasive procedures, judicious use and timely removal of invasive devices, environmental cleaning, and antimicrobial stewardship to reduce resistance. Surveillance, isolation precautions for contagious organisms, and adherence to prevention bundles and checklists are commonly employed as part of patient-safety programs.

Impact is significant, including longer hospital stays, higher morbidity and mortality, and increased healthcare costs. The term is often used interchangeably with hospital-acquired infection, though some guidelines distinguish hospital-acquired infections from broader healthcare-associated infections that occur in other care settings.