What is Hospital-Acquired Infections?
Hospital-acquired infections, sometimes called healthcare-associated infections, are infections that a patient did not have or show signs of when they were admitted to the hospital. Instead, these infections usually show up 48 hours or more after a patient has been admitted to the hospital. Monitoring these infections is a primary concern for organizations like the National Healthcare Safety Network, a part of the Center for Disease Control and Prevention. Their goal is to prevent these infections and improve the safety of patients.
Some examples of these infections include central line-associated bloodstream infections, catheter-associated urinary tract infections, surgical site infections, hospital-acquired pneumonia, ventilator-associated pneumonia, and a specific type of infection caused by the bacteria Clostridium difficile.
Over the past several decades, hospitals have been taking these infections very seriously. They’ve created systems to track and keep an eye on infections. They also have strategies to prevent them and lower the rate at which they occur. Hospital-acquired infections matter beyond individual patients. These infections can spread within the community and can lead to difficult-to-treat infections resistant to many drugs.
Identifying patients who are more likely to get hospital-acquired infections or multidrug-resistant infections is crucial to prevent and reduce these types of infections.
Pneumonia definitions have been updated by the Infectious Disease Society of America and the American Thoracic Society to help identify patients at risk for these multidrug-resistant infections and avoid overusing antibiotics. The term ‘healthcare-acquired pneumonia’ has been replaced with ‘hospital-acquired pneumonia.’ It is defined as pneumonia appearing 48 hours or more after a patient is admitted to the hospital and did not seem to be present at the time of admission.
‘Ventilator-associated pneumonia,’ on the other hand, is defined as pneumonia that develops more than 48 to 72 hours after a patient has been intubated, or had a tube placed in their windpipe to assist with breathing. Both these types of pneumonia can have serious effects, leading to significant illness and death worldwide.
What Causes Hospital-Acquired Infections?
The risk of catching an infection in the hospital depends on the infection control measures at the hospital, the patient’s immune system, and how common different germs are within the community. Risk factors that increase the chances of getting an infection in a hospital include having a weak immune system, being older, long hospital stays, having multiple ongoing illnesses, regularly visiting healthcare facilities, needing mechanical ventilatory support (machines to help you breathe), recent invasive procedures, use of indwelling devices (like catheters), and stays in an intensive care unit (ICU).
Patients who have received antibiotics through an IV in the past 90 days are more likely to develop resistance to multiple drugs. While hospitalizations are necessary for managing severe illnesses, they also increase the risk of patients catching infections from germs that are often resistant to antibiotics. These germs can be caught from other patients, hospital staff, or the hospital environment. The risk is highest among ICU patients. Big studies have found that about 19.5% of ICU patients had at least one infection they caught in the hospital.
Clostridium difficile is a type of bacteria that causes a condition known as Clostridium difficile colitis (an inflammation of the colon). Other common bacteria associated with hospital-acquired infections include Candida spp, Enterobacteriaceae, and Staphylococcus aureus. Common bacteria known to cause urinary tract infections caught in hospital settings include Enterococcus, Staphylococcus aureus, Pseudomonas, Proteus, Klebsiella, and Candida. Based on reports from the National Healthcare Safety Network, the most common germs causing surgical site infections include Staphylococcus aureus, coagulase-negative Staphylococcus, Enterococcus, E Coli, Pseudomonas aeruginosa, Enterobacter, and Klebsiella pneumoniae. The most common bacteria causing pneumonia in hospitals and specifically in ICU ventilator patients include Staphylococcus aureus and Pseudomonas aeruginosa, while E Coli and Klebsiella pneumoniae are seen more frequently in children.
Risk Factors and Frequency for Hospital-Acquired Infections
In 2014, the CDC (Centers for Disease Control and Prevention) published a study that looked at a group of 11,282 patients from 183 hospitals across the United States. The study showed that 4% of these patients in the hospital had at least one healthcare-associated infection. To give you a better idea of what that means in real numbers, in 2011, around 648,000 hospitalized patients had 721,800 infections.
The most common infections found were pneumonia and surgical site infections (both 21.8%), gastrointestinal infections (17.1%), urinary tract infections (12.9%), and primary bloodstream infections (9.9%). The latter includes infections related to the use of catheters.
As for the germs causing these infections, the majority were C. difficile (12.1%), followed by Staphylococcus aureus (10.7%), Klebsiella (9.9%), and Escherichia coli (9.3%). Staphylococcus aureus often causes skin and surgical site infections and sometimes these are caused by a strain of this bacteria that is resistant to common antibiotics, known as MRSA.
A separate study, the SENIC study, suggested that this number of infections could potentially be reduced by a third if hospitals closely tracked infections and put infection control programs in place. Since this study, there has been greater awareness and more preventative measures in place in hospitals, leading to a reduction in some healthcare-associated infections. For example, the CDC reports that the rates of bloodstream infections related to catheters decreased by 46% between 2008 and 2013.
Signs and Symptoms of Hospital-Acquired Infections
Understanding if an infection happened before going to the hospital or while in the hospital, is important information. It can be gathered through detailed questions about symptoms and a physical examination. Symptoms can indicate if the infection was hospital-acquired or not. This might include chills, fever, or night sweats.
Typical symptoms of infection may include:
- Fever
- Chills
- Changes in mental state
- Cough with mucus
- Shortness of breath
- Rapid heart rate
- Abdominal pain
- Pain in the back below the ribs
- Pain in the lower belly above the pubic bone
- Frequent urination
- Painful urination
- Diarrhea
Vital signs like temperature, breathing rate, heart rate, and blood pressure might indicate a body-wide inflammation or infection.
Any external medical devices such as breathing tubes, catheters, lines for fluid or medication, insulin pumps, and heart devices must be looked at too. Information regarding where and when the device was placed is also important. Central lines, that are placed quickly during emergencies, might need to be reassessed and changed within 24 to 48 hours. This is especially true if there was a risk of infection when the line was placed or a new fever during the hospital stay. Central venous catheters are often associated with hospital-acquired blood infections. Other sources of these infections could be catheter-associated urinary tract infections and ventilator-associated pneumonia. Infections can also develop at surgical sites or places where skin is broken. These must be checked daily for any signs of infection.
Regular and careful examinations are very helpful. They can help to identify infections early, manage them, and prevent complications. Evaluations of the abdomen and stool samples might be necessary to check for a clostridium difficile infection.
Testing for Hospital-Acquired Infections
Laboratory tests are an essential part of the process when figuring out the source of an infection and identifying whether any organs are not working properly. These tests may include measuring lactic acid, liver enzymes, clotting time (known as prothrombin time), and levels of blood urea nitrogen (BUN) and creatinine in your blood. These tests can all help to reveal signs of poor blood flow (or hypoperfusion).
Other key findings from these tests might include an unusual high or low white cell count, high levels of immature white cells (known as bands), low platelet count (thrombocytopenia), low or high blood sugar, and reduced oxygen levels in mixed venous blood. These findings help doctors to understand what type of infection you have and its severity.
Before starting antibiotics, it’s important to get samples for cultures. This helps identify the specific germs causing the infection and their resistance or sensitivity to different antibiotics. This information helps doctors narrow down from a wide range of antibiotic options to a more targeted treatment specifically effective against the identified germs.
Tests that don’t affect the doctor’s decisions about your care, or your health progress, are usually not recommended. If it’s highly likely you have a hospital-acquired infection such as ventilator-associated pneumonia (known as VAP), then additional tests like C-reactive protein (CRP) and procalcitonin are not typically needed.
In the case of pneumonia linked to hospital stay or the use of ventilators (HAP/VAP), recent guidelines recommend getting a sample from the trachea without being invasive, a method known as tracheal aspiration. This method has been found to be just as effective as more invasive techniques, like flushing the trachea or examination by way of bronchoscopy.
Treatment Options for Hospital-Acquired Infections
If a patient acquires an infection while in the hospital, the treatment generally involves the use of antibiotics, targeted therapies if the patient is severely unwell (septic), fluid administration to increase blood flow, and careful monitoring to detect any signs of organ failure. To maintain adequate hydration levels in the body, the patient may be given fluids and the medical team will continually assess the patient’s health and any signs that their blood circulation is improving.
The antibiotics prescribed are usually dependent on certain risk factors, especially if there is the presence of Multi-Drug Resistant (MDR) pathogens, or disease-causing microorganisms that are resistant to a variety of antibiotics. Antibiotics should ideally be administered within an hour when a bloodstream infection is suspected, caused by a central line (a long tube placed in a large vein to provide medication or fluid). Before starting antibiotic treatment, blood samples are taken from a superficial vein and from the central line, if applicable. If the patient is showing signs of low blood pressure, poor blood flow or organ failure, the central line should be immediately removed and sent for testing.
In the case of urinary tract infections acquired from urinary catheters (a flexible tube passed through the bladder to drain urine), the catheter is replaced and a urine sample collected from the new catheterr for testing before antibiotics are given. Furthermore, if the catheter no longer serves a purpose, it should be removed. Antibiotic treatment typically lasts for seven days, but in severe cases, can be extended to even fourteen days.
For patients with hospital-acquired pneumonia, antibiotics are usually given for a period of seven days unless otherwise required. Antibiotics used will often be effective against Staphylococcus aureus and Pseudomonas aeruginosa, two common bacteria that cause infections.
Efforts at minimizing central line-associated bloodstream infections have been quite successful, mainly due to better hygiene practices during the insertion and removal of catheters, careful and timely removal of unnecessary catheters, and the use of special dressings and locking solutions for catheters. Depending on the severity of the infection and whether the catheter was removed or left in place, the course of antibiotics may differ.
Clostridium difficile infections, which cause diarrhea and other intestinal issues, are typically treated with oral vancomycin, an antibiotic. If necessary, physicians might adjust the types and combinations of antibiotics being used. As an alternative, a drug called metronidazole can be used. There are also newer medications like fidaxomicin. Microbiota transplantation, a procedure where stool from a healthy person is transferred into the patient’s gut, is sometimes considered for severe cases.
For surgical wound infections, maintaining good hand hygiene and following proper infection prevention measures are critical. Additionally, early use of antibiotics to cover the likely pathogens is often employed and later adjusted based on culture and sensitivity results. The use of precautions such as washing hands using soap and water or alcohol-based disinfectants before and after attending to each patient is a key step in limiting the spread of MDR pathogens. A study revealed that while gloves and gowns are important, by themselves they are not sufficient to prevent the spread of infections.
What else can Hospital-Acquired Infections be?
These are some conditions that can occur due to various types of infections:
- Bacterial sepsis
- Clostridium Difficile Colitis
- Pseudomonas infection
- Acinetobacter infection
- Enterococcal infections
- MRSA (a type of Staph infection)
- Legionella (a type of bacteria causing respiratory diseases)
- Viral hepatitis
- HIV
- Tuberculosis
Possible Complications When Diagnosed with Hospital-Acquired Infections
- Blood infection (Sepsis)
- Brain and spinal cord inflammation (Meningitis)
- Heart lining infection (Endocarditis)
- Bone infection (Osteomyelitis)
- Abdominal lining inflammation (Peritonitis)
- Lung damage (ARDs)
