Nosocomial Infections

What is Nosocomial Infections?

Nosocomial infections, also known as healthcare-associated infections (HAI), are infections you can get while receiving medical treatment. These infections weren’t there when you were admitted for care. They can take place in various health care environments, like hospitals, long-term care facilities, and outpatient clinics. Sometimes, these infections can even show up after you’re already discharged. Health care workers can also get infected while working, which are included in HAIs.

Infections happen when disease-causing germs spread to a patient. In today’s health care setting, these infections are often linked to surgeries, medical procedures, or the use of medical or prosthetic devices. Different types of germs can cause HAIs, including bacteria, viruses, and fungi. The cause of each HAI depends on the type of germ and where the infection occurred.

HAIs are the most common harmful events in health care that can affect patient safety. They can cause serious illness, increase the risk of death, and lead to additional medical costs for patients, families, and healthcare systems. The development of germs resistant to multiple drugs is another problem associated with HAIs. Inside the United States, HAIs affect about 3.2% of all hospital patients. This percentage rises to 6.5% in the European Union and other European countries. The actual number worldwide could be even higher, but it’s challenging to get these figures without comprehensive systems for monitoring these infections. However, great efforts are being made to develop better ways to track and control infections.

What Causes Nosocomial Infections?

A Healthcare-Associated Infection (HAI) is an illness that a patient contracts while receiving treatment in a healthcare setting such as a hospital. They can originate from various sources, all linked to different types of HAIs. The Centers for Disease Control and Prevention has broadly classified these infections into several types including:

1. Central line-associated bloodstream infections (CLABSI)
2. Catheter-associated urinary tract infections (CAUTI)
3. Infections acquired at the site of a surgical procedure
4. Pneumonia linked to ventilators

There are other types of HAIs that are not linked to a device like a catheter or a ventilator. These include types of pneumonia not associated with ventilators, infections in the gastrointestinal tract like Clostridioides difficile, bloodstream infections not caused by central catheter use, and other urinary tract infections not linked to catheter use.

HAIs can also be sorted by specific systems in the body they affect, such as ear, eye, nose, and throat infections, skin and soft tissue infections, infections in bones and joints, infections in the brain and spinal cord, and infections in the reproductive tract. Based on a survey from 2015, the most frequent HAI in the US was pneumonia, followed by gastrointestinal infections, surgical site infections, bloodstream infections, and urinary tract infections.

The organisms causing these infections can be bacteria, viruses, or fungi, which often vary depending on various factors like the hospital location and the population being treated. Bacteria are the most common pathogens for infections, followed by fungi and viruses.

Bacterial infections can originate from an external source or from the body’s own flora. When the immune system isn’t working properly, these can lead to opportunistic infections. Common bacteria that are associated with HAIs include Staphylococci, Staphylococcus aureus, Streptococcus species, and Enterococcus, as well as certain types of gram-negative bacteria. Multidrug-resistant bacteria are commonly seen in HAI and are associated with high death rates.

Fungal pathogens can cause opportunistic infections in patients with weakened immune systems or those with devices like catheters. Such fungi include various types of Candida and Aspergillus fumigatus. Virus-related HAIs are less common, but it’s worth noting that acquired cases of hepatitis B and C, as well as HIV, can result from unsafe practices involving needles.

Risk Factors and Frequency for Nosocomial Infections

Nosocomial infections, also known as healthcare-associated infections (HAI), significantly affect patients worldwide. They cause increased death rates and place a financial burden on healthcare systems. The precise global impact of these infections isn’t fully known due to a lack of data and surveillance systems. However, studies done primarily in the US and Europe provide some insight into their prevalence.

• In Europe, the occurrence of at least one HAI depends on the type of healthcare facility: 4.4% in primary care hospitals, 7.1% in tertiary care hospitals, 19.2% in intensive care units (ICUs), and 3.7% in long-term care facilities.
• In a year, around 8.9 million unique HAI cases occur in acute care and long-term health care facilities within the European Union.
• In the US, according to a 2015 survey, the prevalence of HAI among hospitalized patients was 3.2%, which was notably lower than in a 2011 study which reported a 4% rate.
• The same study revealed that among HAIs in US health facilities, 36.4% happened in critical care areas, 57.5% in ward or nursery areas, and 6.1% in step-down or specialty care units, or mixed acuity locations (different levels of acute care).
• In the US in 2015, about 687,200 HAIs occurred in hospitals, affecting 633,300 patients. This was a promising decrease compared to 2002, when approximately 1.7 million HAIs were reported in US hospitals.
• Developing countries appear to have a higher prevalence of HAIs, with a pooled analysis from various developing countries showing a 15.5% prevalence. These mostly occur as ventilator-associated pneumonia and neonatal infections in ICUs.
• A review of HAI in Southeast Asian countries found the overall prevalence to be 9.1%.

Signs and Symptoms of Nosocomial Infections

Healthcare-associated infections (HAI) may differ in symptoms, depending on the type of infection, the pathogens involved, and the severity of the illness. Here, some types of HAIs have been elaborated:

• Central Line-Associated Blood Stream Infection (CLABSI): Symptoms usually include fever and chills due to harmful bacteria. Other signs may be redness or discharge at the site where the central line was inserted and issues with the central line itself. More serious symptoms may include inflammation of the heart’s inner lining, inflammatory clot, septic arthritis, bone infection, or abscess.
• Catheter-Associated Urinary Tract Infection (CAUTI): Symptoms are similar to regular urinary tract infections. But these typically occur with urinary catheters, either during use or within the first 48 hours of removal. Symptoms can include fever, lower back or belly pain, blood in urine, blockage of the catheter, and symptoms of a urinary tract infection like painful urination or need to urinate.
• Skin and Soft Tissue Infection (SSI): Symptoms vary based on the type of infection and pathogens. Signs of inflammation like redness, warmth, pain, discharge, and wound rupture are common. Some deep tissue infections may be hidden and present with systemic signs like fever, shakes, severe pain, and elevated white blood cell count.
• Pneumonia: Common symptoms include fever, cough with phlegm, and declining oxygen levels if the symptoms occur after 48 hours of being in the hospital or on a ventilator. Patients on mechanical ventilation may experience increased oxygen requirements and the presence of pus in the respiratory tracts. Listening to the lungs may reveal coarse breathing sounds or crackles.
• Healthcare Facility Onset C. difficile Infection (HO-CDI): This should be suspected if there are unexplained symptoms like multiple episodes of loose stools within a short period post-hospitalization. Other symptoms may include belly pain, bloating, cramps, fever, nausea, loss of appetite, and dehydration, usually associated with recent antibiotic use.

It’s important to remember that the elderly or people with a weakened immune system may not exhibit strong responses to infection. In such cases, doctors need to be highly alert to subtle signs of infection like changes in awareness, lethargy, fatigue, and changes in heart rate, blood pressure, or breathing.

Testing for Nosocomial Infections

To confirm the diagnosis of a healthcare-associated infection (HAI), a series of tests are carried out alongside clinical symptoms and physical examinations. These tests include routine blood exams, metabolic checks, markers of inflammation, and blood gas analysis. Each type of HAI requires a specific set of tests, some of which are detailed below.

A Central Line-Associated Blood Stream Infection (CLABSI) may be suspected based on clinical signs. If this is the case and no other localized infection is detected, blood cultures (testing samples of blood for infection) should be obtained. Ideally, these should be taken from two different sites, one from the central venous catheter (a tube inserted into a large vein) and another from a vein near the skin’s surface. Before beginning antibiotics for treatment, any puss-noted material at the site of the catheter exit should also be tested for infection.

For a Catheter-Associated Urinary Tract Infection (CAUTI), urine samples should ideally be collected midstream after removing the urinary catheter. Urinalysis (urine sample testing) and urine cultures will be carried out to determine the presence and type of infection. Bacteria presence in the urine without symptoms of a urinary tract infection is known as asymptomatic bacteriuria, which is usually not treated. If symptoms of a CAUTI are present but not explained by another type of infection and the urine culture shows significant growth of infection, a CAUTI diagnosis is made.

Skin and Soft Tissue Infections (SSI) are evaluated by the clinical presentation. If an SSI is suspected, a culture can be taken from the infected tissue or any draining or purulent (puss-filled) material. Images (e.g., ultrasound or CT scan) can be used to identify infections that occupy space within the body and guide the drainage of infected fluid or abscesses.

Hospital-Acquired Pneumonia (HAP) or Ventilator Associated Pneumonia (VAP) can be assessed further with chest x-rays and tests for microorganisms. Sputum samples (mucus from the respiratory tract) are also taken for testing. Depending on the situation, special mediums may be required to grow and identify specific organisms.

In the case of an infection with C. difficile, stool tests are carried out to identify the presence of C. difficile toxins or genes. Liquid stool from severe diarrhea should be the only one used as a sample. Tests with high-sensitivity like Nucleic Acid Amplification Testing (NAAT) may lead to over-diagnosis and unnecessary treatment. In cases of inconclusive tests, an algorithmic approach and further confirmatory testing with NAAT is recommended. Colonoscopy (examination of the colon) is typically not used for diagnosing C. difficile infections, but conditions such as pseudomembranous colitis found during such procedures are strong indicators of this type of infection. In serious situations, imaging tests might be needed to check for complications like toxic megacolon (a dangerous widening of the colon) or perforation.

Treatment Options for Nosocomial Infections

When treating a Central Line-Associated Blood Stream Infection (CLABSI), you may need to remove the central venous catheter (CVC), a small, flexible tube placed in a large vein. This decision depends on the kind of infection. Some specific infections call for the catheter to be removed and replaced once blood tests show no more infection. The treatment and its length depend on the type of infection and how severe it is. A second round of blood tests should be done to make sure the infection is gone. Prevention is key for avoiding these infections – healthcare providers should maintain clean hands, disinfect the skin, and use sterile procedures. They also regularly check the need for the catheter and aim to use as few as necessary.

Catheter-Associated Urinary Tract Infection (CAUTI) is typically managed with medications and catheter care. One of the most important steps in preventing these infections is minimizing the use and duration of catheters. Doctors should regularly reassess the need for keeping the catheter in place. It’s suggested that patients needing long-term catheterization opt for intermittent catheterization as it has lower chances of infection. If your urinary catheter has been used for two weeks, it should be removed to prevent infection, as biofilm (a layer of bacteria) may have formed. The choice of medication depends on the results of your culture tests. There’s some debate on whether antimicrobial catheter rinses and antimicrobial-coated catheters are effective; some worries exist that these methods may lead to increased drug resistance.

Skin and Soft Tissue Infection (SSI) is treated by cleaning dead tissue and draining infected fluids. Initially, broad treatment is used to cover common infections associated with the specific site. Tests help in tweaking the medication to match the infection and the patient’s condition. Preventing these infections requires steps before, during, and after surgery. This includes reducing risk factors that can be controlled, using pre-surgery antibiotics if needed, and cleaning the skin of specific pathogens. Hair removal is usually not needed and may even introduce bacteria if the area is shaved, so clipping hair is the better choice if needed. Steps during surgery include maintaining temperature, fluid balance, and oxygen levels. Blood sugar should be controlled as well. Post-surgery measures include keeping the area clean, monitoring incision sites, and possibly using antibiotics in certain situations.

Hospital-acquired (HAP) and ventilator-associated pneumonia (VAP) treatment should be guided by results of respiratory cultures. If a sample cannot be taken, treatment should be based on hospital guidelines. Patients should be checked daily for continued need for treatment. In the case of suspected pneumonia caused by choking on food or drink (aspiration pneumonia), treatment should cover mouth bacteria. If symptoms aren’t improving within 72 hours or the patient’s condition is worsening rapidly after starting treatment, further tests should be done to check for complications or other sources of infection. To prevent pneumonia, exposure to mechanical ventilation should be limited, sedation levels should be low and patients should be moved around as soon as possible.

Hospital-acquired C. difficile Infection (CDI) is treated much like community-acquired CDI. If the infection is linked with antibiotic use, the first step is to stop the offending antibiotic if possible. Some medications work specifically against C. difficile. The length of treatment depends on concurrent antibiotic use, the illness severity, and recurring disease. In severe cases, there may be need for surgical evaluation and fecal microbiota transplantation (a procedure to replace healthy bacteria in the gut). It’s essential to closely monitor for clusters of CDI infections in healthcare facilities, for early detection, promptly isolate, and implement infection control, proper hand washing, clean and disinfect the environment and use antibiotics wisely.

What else can Nosocomial Infections be?

What healthcare professionals believe might be causing a healthcare-associated infection (HAI) is dependent on factors like how the symptoms are presented, the type of infection and any risk factors that make a certain type of infection more likely. It’s particularly important to figure out whether an infection was picked up at the community level or during healthcare treatment, because the bacteria involved and their resistance to antimicrobials are different in cases of HAIs compared to non-HAIs.

Being able to tell the difference between a HAI and a community-acquired infection helps medical staff treat and manage the patient’s condition in the most effective way. For this reason, it’s crucial to track and understand when symptoms began. Different types of infections will show up after different types of exposure, such as taking a broad-spectrum antibiotic, having a central venous catheter (CVC), or having a urinary catheter. The timing of the symptoms can often indicate if the infection was present before, or developed after, a specific medical intervention or hospitalization. Many HAIs can mimic the symptoms of their community-acquired counterparts.

For example, if there’s bacterial contamination in the bloodstream (also known as bacteremia) without a CVC in play, other potential sources that could be causing the bacteremia need to be looked into. In situations where bacteremia develops when a CVC is present, other potential sources of infection need to be ruled out. Bacteremia can come from numerous sources, including infection in a wound, urinary tract infection, pneumonia, and endocarditis. It’s crucial to evaluate the timing of symptom onset and whether symptoms started while a CVC was in place or within 48 hours of removing one.

In regard to urinary tract infections associated with catheter use (CAUTIs), it’s vital to differentiate between a CAUTI and a urinary tract infection that was acquired at the community level, which would occur without the presence of a urinary catheter. Symptoms of urinary tract infections can resemble lower urinary tract infections, like acute cystitis or urethritis, or upper urinary tract infections, like pyelonephritis, nephrolithiasis, and ureteritis.

Post-operation fevers might occur due to conditions like pneumonia due to collapsed lung (atelectasis), urinary tract infection, side effects from medications, or drug reactions. There are other conditions that could cause pain at the surgical site, but aren’t necessarily considered a skin and soft tissue infection (SSI), such as wound dehiscence, wound herniation, cellulitis, burns, gas gangrene or muscle cell death (myonecrosis), the process of tumor formation, and inflammation of a vein caused by a blood clot or septic thrombophlebitis. A diagnosis of SSI would require clinical signs of infection and specific criteria to be met, such as purulent discharge, positive cultures, or findings from a radiographic image. But the criteria can vary depending on the class of the infection.

In cases of pneumonia, the timing of onset of respiratory symptoms should help the physician distinguish between pneumonia that was community-acquired and pneumonia that was acquired in the hospital. Hospital-acquired pneumonia (HAP) will present symptoms after 48 hours of being in the hospital or receiving ventilation. HAP can be confused with other conditions, such as chronic obstructive pulmonary disease (COPD), asthma, fluid in the lungs, bronchiectasis, or a blocked blood vessel in the lung. Upper respiratory tract infections can also look like pneumonia. The differential diagnosis for ventilator-associated pneumonia (VAP) includes severe breathing problem due to liquid in the lungs, inflammation in the lungs, abnormal bleeding in the lungs, a blocked blood vessel in the lung, a tumor in the lung, and a reaction to a medication.

For hospital-acquired C. difficile infection (HO-CDI), it’s important to differentiate between other infections or reasons that aren’t infectious in nature that could be causing diarrhea. Noninfectious causes of diarrhea could be due to antibiotic-associated diarrhea not related to C. difficile, inflammatory bowel disease, irritable bowel syndrome, diarrhea due to inability to absorb nutrients from food, or microscopic colitis. Infectious diarrhea can be linked to viruses, fungi or bacterial pathogens. Diarrhea due to antibiotics can also be caused by S. aureus, Salmonella, Bacteroides fragilis, Clostridium perfringens, or Klebsiella oxytoca. An acute abdomen associated with CDI can look like ileus, colonic pseudo-obstruction, ischemia, or volvulus.

There are other types of HAIs that could occur, though they’re less common. These could be infections of the soft tissue, upper respiratory tract, central nervous system, or reproductive tract. Generally speaking, an infection could be a HAI if symptoms began after receiving medical treatment. Possible infections can range widely and often resemble the community-acquired version of the infection.

What to expect with Nosocomial Infections

The outcome of a healthcare-associated infection (HAI) can depend on several factors, such as the type of infection, how severe the illness is, and what type of bacteria or virus caused it. The overall effects and death rates of these infections around the world are not completely known, due to limited monitoring and research. However, we can have some idea of the global impact of these infections from various studies.

Fatality rates linked to HAI are difficult to pinpoint, but some studies suggest about 10% of patients who have an HAI die within 30 days. Others estimate overall death rates associated with these infections can range from 12 to 80%. This wide range depends on how the death rate is calculated and who is being studied. Patients in critical care seem to run a higher risk of death from an HAI, even when considering their initial health condition.

An international study showed the death rate in intensive care units from these infections was 25%, compared to 11% for those without an infection. Overall hospital death rates doubled for patients with these infections, from 15% to 30%. Data from hospitals in Latin America, Africa, Asia, and Europe also showed an excess death rate ranged from 18.5% to 29.3%, depending on the type of HAI.

In 2002, it was estimated that almost 99,000 deaths in US hospitals were associated with these infections. The types of infections contributing to this number included pneumonia, bloodstream infections, urinary tract infections, surgical site infections and infections in other parts of the body.

These infections also added to the length of hospital stays. Research from a German hospital showed that the increase in stay length depended on where and how the infection was acquired. On average, these infections resulted in 12 more day of hospital care. But this varied depending on the type of infection, adding as much as 3.3 to 25.6 extra days. In developing countries, these infections resulted in 5 to 23 additional days in hospital.

The financial cost of these issues is also significant. In the US alone, the main types of these infections cost about $9.8 billion each year in adult inpatient facilities. The costliest infections, in order, were surgical site infection, ventilator-associated pneumonia, central line-associated blood stream infection, Clostridioides difficile infections and catheter-associated urinary tract infections. It’s estimated that healthcare-associated infections cost the US healthcare system from $28 billion to $45 billion annually. In Europe, the associated costs are about €7 billion each year.

Possible Complications When Diagnosed with Nosocomial Infections

The complications that may arise from healthcare-related infections can differ greatly and are influenced by factors like the specific type of infection, the seriousness of the disease, and the causing organism. Below are the usual complications for each type of healthcare-related infection:

Hospital Acquired Pneumonia (HAP) / Ventilator Associated Pneumonia (VAP) Complications:

• Respiratory failure
• A Collection of pus in a body cavity (Empyema)
• Fluid around the lung (Parapneumonic effusions)
• A type of serious infection (Sepsis)

Central Line-Associated Blood Stream Infection (CLABSI) Complications:

• Painful vein inflammation with pus formation (Suppurative thrombophlebitis)
• Infection of heart’s inner lining (Endocarditis)
• Infection in a joint (Septic arthritis)
• Infection and inflammation of the bone (Osteomyelitis)
• A localized collection of pus (Abscess)
• Serious infection (Sepsis)

Catheter-Associated Urinary Tract Infection (CAUTI) Complications:

• Infection in the upper part of the urinary system
• Serious infection (Sepsis)

Skin and Soft Tissue Infection (SSI) Complications:

• Delayed healing of the wound
• Rejection of implanted medical devices or prosthetics
• Requirement for repeated surgery or removal of infected devices or prosthetics
• A localized collection of pus (Abscess)
• Infections in body cavities
• Serious infection (Sepsis)

Hospital Acquired C. difficile Infection (HO-CDI) Complications:

• Repeated or hard-to-treat infections
• Ileus with toxic megacolon (Serious complications of the bowel)
• Severe loss of bodily fluids (Dehydration)
• A severe infection (Sepsis)

Preventing Nosocomial Infections

Preventing infection, especially in a healthcare setting, is very important. A key way to avoid the spread of infection is by regularly washing hands. This helps get rid of harmful germs that can cause diseases. According to the World Health Organization, there are five key moments when healthcare workers should always wash their hands: before touching a patient, before doing any clean or sterile procedure, after being in contact with body fluids, after touching a patient, and after touching anything in the patient’s surroundings.

Using alcohol-based hand sanitizers is recommended over soap and water except in cases where the hands are visibly dirty, after going to the bathroom, or after being in contact with certain bacteria like C. difficile. Research studies have found out that following these hand hygiene recommendations helps reduce germs and prevents the spread of healthcare-associated infections.

Healthcare workers should also practice standard precautions to protect themselves. These precautions include wearing personal protective equipment such as gloves, protective clothing, masks, and eye protection to shield from potentially infectious blood and body fluids. Extra precautions should be taken to prevent airborne diseases, infections that spread through droplets, and direct contact transmission. For airborne diseases, a well-fitted N-95 respirator and patient isolation in a room with special air filters are recommended. Masks and maintaining a safe distance can help prevent droplet spread. Gowns and gloves should be worn when taking care of patients with multiple drug-resistant bacteria and C. difficile to avoid direct contact.

The healthcare environment could also be a source of germs. Objects like water taps, door handles, and work surfaces should be kept clean as they are found to harbor a high number of germs. Medical equipment and the patient surroundings should also be cleaned regularly. Waste materials from the hospital should be disposed of properly since they could also be a source of harmful bacteria. Enforced cleaning regimens can help prevent the spread of infection in a healthcare setting.

A crucial aspect of preventing infections is the rational use of antibacterial drugs. Excessive or unnecessary use of antibiotics can lead to some bacteria becoming resistant to these drugs, and this could be harmful to the patient. It’s estimated that about half of the antibiotics prescribed aren’t really necessary. Therefore, it’s important for healthcare providers to promote rational use of antibiotics.

Patients should be educated about the possible risk of acquiring an infection while receiving care. Knowing the risk factors can enable patients to take measures that lower their chances of getting an infection. Patients should avoid habits like smoking and keep the surgical site clean before a procedure. It’s also important to avoid unnecessary invasive procedures. Patients should also be educated about when it is necessary to take antibiotics to prevent misuse.