Nosocomial infections in the intensive care unit

Nosocomial infection in the intensive care unit (ICU) is associated with increased mortality, morbidity and length of stay. It is defined as infection that begins 48 hours after admission to hospital. The commonest types are ventilator-associated pneumonia (VAP), central line-associated bloodstream infection (CLABSI), urinary catheter-related infection and surgical site infection. The common pathogens include Staphylococcus aureus, Pseudomonas aeruginosa, Candida, Escherichia coli and Klebsiella species. Antimicrobial resistance is increasing and has emerged from selective pressure from antibiotic use and transmission via health workers. Prevention of infection is fundamental and can be achieved through good antimicrobial use and infection control, including hand hygiene. Grouped, easy-to-follow best practice activities called 'care bundles' have been developed to prevent VAP and CLABSI. Microbiological cultures are central to rapid and accurate diagnosis, which improves outcomes and reduces resistance. The principles of treatment include early antimicrobial therapy (after appropriate specimens are taken) targeted to the local microbes, then de-escalation according to culture and susceptibility results. This article summarizes the pathogenesis, risk factors, microbiology, diagnosis, prevention and treatment of VAP, CLABSI and nosocomial urinary tract infection in the adult ICU.