Infection, Health Care–Associated

Key Features

Essentials of Diagnosis

• Health care–associated infections are acquired during the course of receiving health care treatment for other conditions

• Hospital-associated infections are defined as those not present or incubating at the time of hospital admission and developing at least 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

General Considerations

• Although most fevers are due to infections, about 25% of patients with fever will have a noninfectious origin

• Many infections are a direct result of the use of invasive devices for monitoring or therapy such as

  • Intravenous catheters

  • Indwelling urinary catheters

  • Drainage catheters placed by interventional radiology

  • Orotracheal tubes for ventilatory support

• Early removal of such devices reduces infection

• Patients in whom health care–associated infections develop

  • Are often critically ill

  • Have been hospitalized for extended periods

  • Have received several courses of broad-spectrum antibiotic therapy

• As a result, the causative organisms are often multidrug resistant and different from those in community-acquired infections

  • Staphylococcus aureus and Staphylococcus epidermidis (a frequent cause of prosthetic device infection) may be resistant to methicillin and most cephalosporins (except ceftaroline, which is the only cephalosporin active against methicillin-resistant S aureus) and require vancomycin for therapy

  • Enterococcus faecium is resistant to ampicillin and vancomycin

  • Gram-negative infections caused by Pseudomonas, Citrobacter, Enterobacter, Acinetobacter, Stenotrophomonas, and extended-spectrum beta-lactamase (ESBL)–producing Escherichia coli and Klebsiella and carbapenem-resistant Enterobacteriaceae may be resistant to most antibacterials

Demographics

• Worldwide, approximately 10% of patients who enter the hospital free of infection acquire a health care–associated infection resulting in

  • Prolongation of the hospital stay

  • Increase in cost of care

  • Significant morbidity and mortality

Clinical Findings

Symptoms and Signs

• Those of the underlying disease

Differential Diagnosis

• Noninfectious

  • Drug fever

  • Nonspecific postoperative fevers (tissue damage or necrosis)

  • Hematoma

  • Pancreatitis

  • Pulmonary embolism

  • Myocardial infarction

  • Ischemic bowel

• Urinary tract infections

• Pneumonia

• Gastrointestinal tract infections, eg, Clostridioides difficile colitis

• Bacteremia, eg, from indwelling catheter, wound, abscess, pneumonia, genitourinary or gastrointestinal tract

• Wound infection, eg, pressure injury

Diagnosis

Laboratory Tests

• Blood cultures are universally recommended

• A properly prepared sputum Gram stain and semi-quantitative sputum cultures may be useful in selected patients where there is a high pretest probability of pneumonia

• Unreliable or uninterpretable specimens are often obtained for culture and result in unnecessary use of antibiotics

  • The best example is the diagnosis of line-related or bloodstream infection in the febrile patient

  • A blood culture from an unidentified site, a single blood culture from any site, ...