Question
Hospital acquired infection
Answer
Hospital-acquired infection (HAI), also called nosocomial infection, is an infection acquired by a patient during the course of receiving healthcare in a hospital or other healthcare facility, which was neither present nor incubating at the time of admission — conventionally defined as occurring 48–72 hours or more after admission (or occasionally, within a defined period after discharge for certain surgical site infections), a timeframe chosen to distinguish it from community-acquired infection present at the time of hospitalization.
Common types/sites:
- Catheter-associated urinary tract infection (CAUTI) — the most common HAI in many settings, associated with indwelling urinary catheters.
- Surgical site infection (SSI) — infection at or near a surgical incision, occurring within a defined post-operative period.
- Central line-associated bloodstream infection (CLABSI) — associated with intravascular catheters.
- Ventilator-associated pneumonia (VAP) — pneumonia developing in mechanically ventilated patients.
- Clostridium difficile-associated diarrhoea — often following antibiotic-disrupted normal gut flora in hospitalized patients.
Common causative organisms: often multidrug-resistant organisms, given the selective pressure of hospital antibiotic use and environment — Staphylococcus aureus (including MRSA), Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli (including ESBL-producing strains), Enterococcus (including VRE), and Clostridium difficile.
Risk factors: invasive medical devices (catheters, ventilators, central lines), prolonged hospital stay, immunosuppression, extremes of age, underlying comorbidities (diabetes, malignancy), broad-spectrum antibiotic use (disrupting normal flora, selecting for resistant organisms), and surgical procedures.
Prevention: strict hand hygiene (the single most important and cost-effective measure), aseptic technique for device insertion/care, minimizing unnecessary invasive device use and duration, antibiotic stewardship, isolation/contact precautions for patients colonized/infected with resistant organisms, environmental cleaning/disinfection, and active infection-control surveillance programmes.
Significance: HAIs are associated with significant morbidity, mortality, prolonged hospital stay, and increased healthcare costs, making infection-control and prevention programmes a major priority in healthcare quality and patient safety initiatives worldwide.