Healthcare Associated Infections


Modern healthcare uses a variety of invasive devices and procedures to treat patients and help them recover from illness. Infections can be associated with the devices used in medical procedures; such infections are known as healthcare associated infections. Healthcare associated infections can occur within any healthcare facility, including hospitals, ambulatory surgical centers, end-stage renal disease facilities, and long-term care facilities. Healthcare associated infections are a significant public health problem causing serious emotional, financial, and medical consequences within communities. Approximately one in 25 patients have acquired an infection related to care they received at a healthcare facility. Each year, healthcare associated infections cause tens of thousands of deaths and cost the United States (U.S.) health care system billions of dollars.

Healthcare Associated Infections Data Overview

Check out the points below for the main takeaways from this page. 

• In 2018, Southern New Hampshire (NH) Medical Center had 51% more hospital associated infections observed than predicted. In the same year, St. Joseph's hospital had 4% fewer hospital associated infections observed than predicted. 

• Among urinary tract infections acquired in the hospital, approximately 75% are associated with a urinary catheter. Southern NH Medical Center had 1% fewer catheter-associated urinary tract infection observed than predicted.  

• Surgical site infections are the most common type of hospital associated infection (22% of all infections). In 2018, St. Joseph's Hospital had 19% more surgical site infections observed than predicted. In the same year, Southern NH Medical Center had 16% more surgical site infections observed than predicted. 

• Antibiotic resistant bacteria have caused concern across the United States, as infections caused by antibiotic-resistant bacteria are difficult, and sometimes impossible, to treat. In 2019, there were 86 cases of Carbapenem-resistant enterobacteriaceae and 132 cases of Pneumococcal disease in NH. 

Standardized Infection Ratio (SIR)

The standardized infection ratio is a measure used to track healthcare associated infectionat the national, state, and local level over time. The standardized infection ratio adjusts for a variety of different factors that contribute to healthcare associated infection risk within each facility. The standardized infection ratio is a ratio of the actual number of healthcare associated infection reported to the predicted number of healthcare associated infections. 

standardized infection ratio greater than 1.0 indicates that more healthcare associated infections were observed than predicted and a standardized infection ratio less than 1.0 indicates that fewer healthcare associated infections were observed than predicted. For example, standardized infection ratio = 0.70 would be interpreted as 30% fewer infections observed than predicted and standardized infection ratio = 1.30 would be interpreted as 30% more infections observed than predicted. 

Using the standardized infection ratio allows us to compare healthcare associated infections across hospitals, procedures, and risk groups, regardless of unique patient or hospital factors that may impact the likelihood of infection. 

Antibiotic Resistant Infections

Antibiotic resistance is one of the biggest public health challenges of our time. 

Each year in the U.S., at least 2.8 million people get an antibiotic-resistant infection, and more than 35k people die (CDC). Antibiotic resistance occurs when bacteria no longer respond to the antibiotics designed to kill them. Infections caused by antibiotic-resistant germs are difficult, and sometimes impossible, to treat. In most cases, they require extended hospital stays, follow-up doctor visits, and costly alternatives. Antibiotic resistance can affect people at any stage of life, as well as the healthcare, veterinary, and agriculture industries, making it one of the world’s most urgent public health problems.  

Carbapenem-resistant enterobacteriaceae

Enterobacteriaceae are a family of different types bacteria that cause infections in healthcare settings. When Enterobacteriaceae develop resistance to the group of antibiotics called carbapenems, the germs are called carbapenem-resistant enterobacteriaceae (CRE). Carbapenem-resistant enterobacteriaceae are usually spread person to person through contact with infected people, particularly contact with wounds or stool by the hands of healthcare workers, or through medical equipment and devices that have been poorly cleaned. Healthy people usually do not get carbapenem-resistant enterobacteriaceae infections, as they are common in patients in hospitals and long-term care facilities.

Carbapenem-resistant enterobacteriaceae infections are a public health threat to patients in healthcare facilities because they are hard to treat. They do not respond to commonly used antibiotics, and sometimes they are resistant to all antibiotics. In 2017, there was an estimated 13k cases of carbapenem-resistant enterobacteriaceae in the U.S, with about 1k deaths. (CDC)

Clostridioides difficile

The CDC has listed Clostridioides difficile (C. diff )as one of the five top urgent antibiotic related threats to human health. Every year in the U.S., there are an estimated 450k people diagnosed with Clostridioides difficile infections, including 29k deaths (i.e., more than one-in-20 estimated to die of their infection). Antibiotic use is associated with a seven to 10 times increased risk of a patient developing a Clostridioides difficile infection within the first month of antibiotic use. This is due to the nature of antibiotics affecting the body's microbiomes by killing bad germs as well as good germs that work to protect your body against infection. Increased risk of Clostridioides difficile can extend for up to three months after a patient stops taking antibiotics.

Invasive Staphylococcus aureus


Methicillin-resistant Staphylococcus aureus (MRSA) is a type of staph bacteria that is resistant to certain antibiotics called beta-lactams. MRSA can cause difficult-to-treat staph infections because of resistance to some antibiotics. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin, and amoxicillin. Most MRSA infections are skin infections that often appear as a bump, a boil, or area that is red, tender and swollen, and is sometimes confused with a spider bite. More severe or potentially life-threatening MRSA infections occur most frequently among patients in healthcare settings.  


Methicillin-sensitive Staphylococcus aureus (MSSA) is a type of staph bacteria that is sensitive to certain antibiotics called beta-lactams. 

Streptococcus pneumoniae

Pneumococcal disease is caused by bacteria called Streptococcus pneumoniae (S. pneumoniae). People with pneumococcal disease can spread bacteria to others when they cough or sneeze. This bacteria can cause infections in many parts of the bodySymptoms depend on the part of the body affected and often include fever, cough, shortness of breath, chest pain, stiff neck, confusion, increased sensitivity to light, joint pain, chills, ear pain, sleeplessness, and irritability. In severe cases, pneumococcal disease can cause hearing loss, brain damage, and even death. Getting vaccinated is the best way to protect against pneumococcal disease.

According to the CDC, there was an estimated 900k infections in 2014, with 3.6k deaths.

Catheter Associated Urinary Tract Infections

A catheter-associated urinary tract infection (CAUTI) occurs when bacteria enter the urinary tract through the urinary catheter and cause infection. Catheter-associated urinary tract infections have been associated with increased morbidity, mortality, healthcare costs, and length of stay. The risk of catheter-associated urinary tract infection can be reduced by ensuring that catheters are used only when needed and removed as soon as possible; that catheters are placed using proper aseptic technique; and that the closed sterile drainage system is maintained. Most catheter-associated urinary tract infections can be treated with antibiotics and/or removal or change of the catheter.

Data Snapshot

Among urinary tract infections (UTIs) acquired in the hospital, approximately 75% are associated with a urinary catheter. Between 15 to 25% of hospitalized patients receive urinary catheters during their hospital stay. (CDC)

Central Line-Associated Bloodstream Infections

A central line-associated bloodstream infection (CLABSI) is a serious infection that occurs when bacteria or viruses enter a persons bloodstream through a central line. A central line is a catheter often placed in a large vein in the neck, chest, or groin to give medication or fluids or to collect blood for medical tests. Healthcare providers are required to follow a strict protocol when inserting, checking, and changing the dressing of a central line to ensure proper infection control practices and prevention of a central line-associated bloodstream infection. Patients who get a central line-associated bloodstream infection usually have a fever and red skin and soreness around their central line. 

Data Snapshot

Central line-associated bloodstream infections result in thousands of deaths in the U.S. each year. These infections cost our healthcare system billions of dollars, yet they are preventable through proper infection control practices. (CDC)

Surgical Site Infections

A surgical site infection (SSI) occurs after surgery in the part of a persons body where the surgery took place. Surgical site infections can sometimes be superficial, on the skin. Other surgical site infections are more serious and can involve tissues under the skin, organs, or implanted material. Symptoms include redness and pain around the area where you had surgery, drainage of cloudy fluid from your surgical wound, and fever.

Data Snapshot

Surgical site infections are the most common type of healthcare associated infection (22% of all infections) with an estimated 157,500 infections per year. Approximately two to five percent of patients undergoing inpatient surgery develop a surgical site infection. Each surgical site infection is associated with approximately 7-10 additional postoperative hospital days. In 2013, acute care hospitals experienced a 19% reduction in surgical site infections compared to 2008.

Health Equity & Healthcare Associated Infections

A person's health can be seriously impacted by their race, ethnicity, gender, income level, education, and other socioeconomic factors. In regards to healthcare associated infections...

• Asian and Hispanic patients had significantly higher rates of healthcare associated infections than white non-Hispanic patients in patients hospitalized with acute cardiovascular disease, pneumonia, and major surgery (Racial and ethnic disparities in healthcare-associated infections in the United States, 2009-2011).

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