ESSENTIALS OF DIAGNOSIS
Health care–associated infections are acquired during the course of receiving health care treatment for other conditions.
Hospital-associated infections are a subset of health care–associated infections defined as those not present or incubating at the time of hospital admission and developing 48 hours or more after admission.
Most health care–associated infections are preventable.
Hand washing is the most effective means of preventing health care–associated infections and should be done routinely even when gloves are worn.
Worldwide, approximately 10% of patients acquire a health care–associated infection, resulting in prolongation of the hospital stay, increase in cost of care, and significant morbidity and mortality. The most common infections are urinary tract infections, usually associated with indwelling urinary (Foley) catheters or urologic procedures; bloodstream infections, most commonly from indwelling catheters but also from secondary sites, such as surgical wounds, abscesses, pneumonia, the genitourinary tract, and the gastrointestinal tract; pneumonia in intubated patients or those with altered levels of consciousness; surgical wound infections; MRSA infections; and Clostridioides difficile colitis.
Some general principles are helpful in preventing, diagnosing, and treating health care–associated infections:
Many infections are a direct result of the use of invasive devices for monitoring or therapy, such as intravenous catheters, indwelling urinary (Foley) catheters, shunts, surgical drains, catheters placed by interventional radiology for drainage, nasogastric tubes, and orotracheal or nasotracheal tubes for ventilatory support. Early removal of such devices reduces the possibility of infection.
Patients in whom health care–associated infections develop are often critically ill, have been hospitalized for extended periods, and have received several courses of broad-spectrum antibiotic therapy. As a result, health care–associated infections are often due to multidrug resistant pathogens and differ from those encountered in community-acquired infections. For example, S aureus and S epidermidis (a frequent cause of prosthetic device infection) are often resistant to methicillin and most cephalosporins (ceftaroline is active against MRSA) and require vancomycin for therapy; Enterococcus faecium resistant to ampicillin and vancomycin; gram-negative infections caused by Pseudomonas, Citrobacter, Enterobacter, Acinetobacter, Stenotrophomonas, extended-spectrum beta-lactamases (ESBL)–producing E coli, and Klebsiella may be resistant to most antibacterials. When choosing antibiotics to treat the seriously ill patient with a health care–associated infection, antimicrobial history and the “local ecology” must be considered. In the most seriously ill patients, broad-spectrum coverage with vancomycin and a carbapenem with or without an aminoglycoside is recommended. Once a pathogen is isolated and susceptibilities are known, the most narrow-spectrum, least toxic, most cost-effective regimen should be used.
Widespread use of antimicrobial medications contributes to the selection of drug-resistant organisms; thus, every effort should be made to limit the spectrum of coverage and unnecessary duration. All too often, unreliable or uninterpretable specimens are obtained for culture that result in unnecessary use of antibiotics. The best example of this principle is the diagnosis of line-related or bloodstream infection in the febrile patient. To avoid unnecessary use of antibiotics, thoughtful consideration ...