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NHSN - Reports 2

Healthcare-associated infections (HAIs) are infections that patients get while they are receiving healthcare or soon after receiving healthcare. The CDC is committed to helping all Americans receive the best and safest care, and HAIs are a major, yet often preventable, threat to patient safety, and the bacterial or fungal pathogens causing these infections frequently develop antimicrobial resistance or are associated with antimicrobial use. HAI data detail progress toward the ultimate goal of eliminating HAIs. While there are many kinds of HAIs, data on this and the following pages focus on infections occurring across the U.S. that are reported to the National Healthcare Safety Network (NHSN).

What is the SIR, and What Does it Mean?

The Standardized Infection Ratio (SIR) is a statistic used to track healthcare associated infections (HAIs) over time, at a national, state, or facility level. The SIR compares the actual number of HAIs at each hospital, to the predicted number of infections. The predicted number is an estimate based on national baseline data, and it is risk adjusted. Risk adjustment takes into account that some hospitals treat sicker patients than others.

The formula for calculating the SIR is: 

SIR calculation equation 

What does the SIR tell me?

If the SIR is less than 1, fewer infections were observed than predicted, or “Better than Expected”

If the SIR is greater than 1, then more infections were observed than predicted, or “Worse than Expected”

If the SIR is 1, then the number of infections is the same as the number of predicted infections.

When the number of predicted infections is less than 1, then the numbers are too small to compare, and no visualizations are generated.

  • Central Line-Associated Bloodstream Infections

    What is a Central Line?

    A central line (also known as a central venous catheter) is a catheter (tube) that doctors often place in a large vein in the neck, chest, or groin to give medication or fluids or to collect blood for medical tests.

    What is a Central Line-Associated Bloodstream Infection (CLABSI)?

    A central line-associated bloodstream infection (CLABSI) is a serious infection that occurs when germs (usually bacteria or fungi) enter the bloodstream through a central line. Healthcare providers must follow a strict protocol when inserting the line to make sure the line remains sterile and a CLABSI does not occur. In addition to inserting the central line properly, healthcare providers must use stringent infection control practices each time they check the line or change the dressing.

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  • Catheter-Associated Urinary Tract Infections

    A urinary tract infection (UTI) is an infection involving any part of the urinary system, including urethra, bladder, ureters, and kidneys. UTIs are the most common type of healthcare-associated infection reported to the National Healthcare Safety Network (NHSN). The most important risk factor for developing a catheter-associated UTI (CAUTI) is prolonged use of a urinary catheter. Therefore, catheters should only be used for appropriate indications and should be removed as soon as they are no longer needed.

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  • Clostridioides difficile Infections

    Clostridioides difficile (C. difficile) is one of the leading causes of healthcare-associated infections in the United States and is also increasingly detected in the community. Most cases of C. difficile infection occur in people taking antibiotics or not long after finishing a course of antibiotics. There are other risk factors: being 65 or older, having a recent stay at a hospital or nursing home, having a weakened immune system, or having a previous C. difficile infection or known exposure to C. difficile bacteria.

    C. difficile bacteria form spores that can survive for long periods in the environment, including on surfaces in healthcare settings. People can become infected if they touch items or surfaces that are contaminated with feces and then touch their mouth or mucous membranes. Healthcare workers can spread the bacteria to patients or contaminate surfaces through hand contact.

    CDC provides guidelines and tools to the healthcare community to help prevent C. difficile infections as well as provides resources to help the public safeguard their own health.

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  • MRSA Bacteremia

    Methicillin-resistant Staphylococcus aureus (MRSA) is a type of staph bacteria that is resistant to many antibiotics. In a healthcare setting, such as a hospital or nursing home, MRSA can cause serious infections such as bloodstream infections, pneumonia and surgical site infections. If not treated quickly, MRSA infections can cause sepsis and death. MRSA is usually spread between patients via the hands of healthcare providers that become contaminated after touching an infected wound or a contaminated surface. Also, people who carry MRSA but do not have signs of infection can spread the bacteria to others.

    CDC provides guidelines and tools to the healthcare community to help prevent MRSA infections as well as provides resources to help the public safeguard their own health.

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