HospitalAcquired

Hospital-acquired infection, also known as nosocomial infection, refers to an infection that a patient develops during a stay in a hospital or other healthcare facility that was not present and not incubating at the time of admission. Most definitions classify an HAI as occurring 48 hours or more after admission, or within a specified window after a surgical procedure or exposure to an invasive device.

The most common HAIs include bloodstream infections, catheter-associated urinary tract infections, ventilator-associated pneumonia, and surgical site infections. Other notable infections include gastrointestinal infections such as Clostridioides difficile, as well as wound, skin, and soft tissue infections. Causative organisms frequently implicated in HAIs include methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), ESBL-producing Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter species, among others. Antifungal and antiviral HAIs also occur, particularly in severely ill or immunocompromised patients.

Risk factors for hospital-acquired infections include the use of invasive devices (such as urinary catheters, central venous catheters, and mechanical ventilation), longer hospital stays, advanced age, immune suppression, recent surgery, and prior antibiotic exposure.

Prevention relies on comprehensive infection prevention programs and adherence to evidence-based practices: strict hand hygiene, appropriate barrier precautions, sterilization and disinfection of equipment, environmental cleaning, antimicrobial stewardship to limit unnecessary antibiotic use, timely removal of unnecessary devices, and care bundles to reduce device-associated infections.

Surveillance systems track HAIs to monitor trends, benchmark performance, and guide prevention efforts. In many countries, data are reported as infection rates per 1,000 patient-days or device-days. Hospital-acquired infections impose additional morbidity, mortality, longer hospital stays, and higher healthcare costs.