Device-related infection is a serious complication that can occur when medical devices implanted in the body become colonized by harmful microorganisms, leading to illness that requires complex treatment and can significantly impact a patient’s quality of life.

Understanding Device-Related Infections

When a doctor places a medical device inside your body—such as a pacemaker to control your heartbeat, a prosthetic joint to replace a damaged knee or hip, or a catheter to help with urinary function—this device can sometimes become infected. A device-related infection occurs when germs such as bacteria, fungi, or viruses settle on the implanted device and begin to grow there. These infections represent one of the most serious complications that can occur after receiving a medical implant, and they affect a substantial portion of patients who rely on these life-saving or life-improving technologies.^[1]

The infection process typically begins when microorganisms attach to the foreign material of the implant. Once attached, these germs undergo changes that allow them to form a biofilm—a protective community of bacterial cells surrounded by a sticky substance they produce themselves. This biofilm acts like a shield, making the bacteria much harder for your immune system to fight and much more resistant to antibiotics that might normally kill them. Because of this protective barrier, the germs can continue to multiply on the device surface, potentially causing damage to surrounding tissues or spreading infection throughout the body.^[2]

Medical devices can include a wide variety of implants. Cardiac devices like pacemakers and defibrillators help regulate heartbeat. Orthopedic implants such as artificial hips, knees, or screws hold bones together. Urological devices like urinary catheters help drain urine. Neurosurgical devices include shunts that drain fluid from the brain. Vascular devices like heart valves or stents keep blood flowing properly. Each type of device carries its own infection risk, and the consequences can range from mild discomfort to life-threatening illness.^[3]

How Common Are Device-Related Infections?

Device-related infections are far more common than many people realize. According to data from the Centers for Disease Control and Prevention, between 50 and 70 percent of all healthcare-associated infections—nearly 2 million cases each year—can be traced back to indwelling medical devices. This means that more than half of all infections people acquire in healthcare settings are connected to devices placed inside their bodies.^[1]

The rate at which these infections occur varies significantly depending on which type of device is involved. Approximately 25 percent of all healthcare-associated infections are specifically device-associated. For some devices, infection rates are relatively low, while for others they pose a much greater threat. The infection rate is consistently higher when a device needs to be replaced or reimplanted compared to when it is placed for the first time. This pattern suggests that each time doctors operate on the area around an implant, there is an increased opportunity for germs to enter.^[3]

Mortality rates associated with device infections also vary widely by device type. Some devices, such as dental implants or urinary catheters, have relatively low death rates of less than 5 percent when infected. However, infections of mechanical heart valves can be deadly in more than 25 percent of cases. These statistics underscore how serious device-related infections can be, particularly when they involve devices located near vital organs or in the bloodstream.^[1]

Over recent years, the number of device-related infections has been rising steadily. One analysis of hospital records covering more than 4 million cardiac device implantations over 16 years found that infection rates increased by 210 percent during that period. The annual rate of infection jumped significantly, rising from 1.53 percent in 2004 to 2.41 percent in 2008. This increase is happening faster than the growth in device use itself, suggesting that factors beyond simply placing more devices are contributing to the problem.^[11]

What Causes Device-Related Infections?

Device-related infections are most commonly caused by bacteria, though fungi and other microorganisms can occasionally be responsible. The infection can begin in several different ways. Most often, germs contaminate the device during the surgery when it is being placed. Even with careful sterilization procedures, bacteria from the patient’s skin, the surgical team, or the operating room environment can sometimes find their way onto the device. Once the device is implanted and the surgical site closes, any bacteria left behind have the opportunity to multiply and establish infection.^[3]

Another route of infection occurs when bacteria traveling in the bloodstream—a condition called bacteremia—settle onto a device that was previously infection-free. This can happen when someone develops an infection elsewhere in their body, such as a urinary tract infection or pneumonia, and the bacteria from that infection enter the bloodstream and travel to the device. Additionally, infection can spread from nearby infected tissue directly to the device through what doctors call contiguous spread.^[3]

The specific types of bacteria that cause device infections vary depending on the type of device and when the infection occurs. Gram-positive bacteria, particularly various species of Staphylococcus, are the most common culprits. Staphylococcus aureus and coagulase-negative staphylococci like Staphylococcus epidermidis are found in many device infections. These bacteria normally live on human skin, which explains why they so easily contaminate devices during surgery. Other gram-positive bacteria that can cause device infections include Enterococcus, Streptococcus, Corynebacterium, and Propionibacterium species.^[3]

Gram-negative bacteria, though less common than gram-positive bacteria, also cause device infections. These include organisms like Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. In rare cases, fungi such as Candida species, nontuberculous mycobacteria, or other unusual organisms may be responsible, particularly in patients whose immune systems are severely weakened.^[3]

The timing of infection provides clues about its source. Infections that occur within the first few weeks after device placement, called early postoperative infections, are typically caused by organisms introduced during surgery, most commonly Staphylococcus aureus. Infections that develop months or years after implantation, termed chronic infections, may be caused by less aggressive bacteria like Staphylococcus epidermidis or Propionibacterium species that grow slowly over time. Infections that appear long after surgery—often two or more years later—are usually caused by bacteria that traveled through the bloodstream from an infection elsewhere in the body.^[3]

Who Is at Higher Risk?

Certain groups of people face a greater chance of developing device-related infections due to various factors that weaken the body’s ability to fight germs or increase exposure to bacteria. Understanding these risk factors is important because it helps doctors and patients take extra precautions when needed.

Age plays a significant role in infection risk. The occurrence of device-related infection is greatest in people over 65 years of age. As the population ages and more elderly individuals receive medical devices, the overall number of infections is expected to continue rising. Older adults often have weaker immune systems and may have multiple health conditions that further compromise their ability to fight infection.^[11]

Several chronic medical conditions increase susceptibility to device infections. Diabetes is a major risk factor because high blood sugar levels can impair the immune system’s function and slow wound healing. People with chronic kidney disease, particularly those requiring dialysis, face higher infection risks because their condition often requires frequent needle insertions and their immune systems may be compromised. Heart failure, chronic obstructive pulmonary disease (COPD), and cancer all increase infection risk, as do conditions requiring immunosuppressive medications—drugs that deliberately weaken the immune system, such as corticosteroids or chemotherapy agents.^[16]

Previous infections, particularly a history of infection in a prior device, significantly increase the likelihood of infection in a new or replacement device. Patients who have already experienced one device infection are at elevated risk for future infections, possibly because the bacteria that caused the first infection may still be present in surrounding tissues or because the initial infection left lasting damage that makes the area more vulnerable.^[3]

Certain medications increase infection risk beyond just immunosuppressants. Anticoagulants—medications that prevent blood clots—are associated with higher infection rates, possibly because bleeding or bruising around the device site can create pockets where bacteria can grow. Antibiotics themselves, while meant to prevent infection, can sometimes backfire by killing off helpful bacteria and allowing resistant strains to flourish.^[11]

The complexity of the device and the surgical procedure also matter. More complex systems, such as cardiac resynchronization therapy devices that require multiple leads threaded into the heart, have higher infection rates than simpler single-chamber pacemakers. Procedures that require reoperation—whether to replace a device, add components, or fix problems—carry substantially higher infection risks than first-time placements. Each time doctors operate on the device pocket or manipulate the leads, there is another opportunity for bacteria to contaminate the hardware.^[12]

Recognizing the Symptoms

The symptoms of device-related infections can vary widely depending on where the device is located, what type of infection has developed, and how long the infection has been present. Clinical presentation ranges from infections with no obvious symptoms to severe systemic illness that can lead to sepsis—a life-threatening condition where the body’s response to infection causes widespread inflammation and organ damage—or septic shock, where blood pressure drops dangerously low.^[3]

Local signs of infection at the device site are often the first clue that something is wrong. These signs include redness of the skin around the implant, warmth when you touch the area, swelling, pain or tenderness, and drainage of fluid from the surgical wound. The skin over the device might look inflamed or feel hot compared to surrounding skin. In some cases, the skin may break down, forming an ulceration—an open sore—that exposes the device beneath. The device itself might become visible through the skin or might feel like it is moving more than it should, suggesting the pocket is infected and the tissues are breaking down.^[3]

Systemic symptoms indicate the infection has spread beyond the device site into the bloodstream or other parts of the body. Fever is a common systemic symptom, as are chills and sweating. Patients may feel generally unwell, with fatigue, weakness, or body aches. When devices are located in or near the heart, infected bacteria can break off and travel through the bloodstream to other organs, causing embolic phenomena—blockages in blood vessels that can lead to strokes, kidney damage, or other serious complications.^[2]

Sometimes infections cause local tissue damage beyond just redness and swelling. The infected device may loosen from its proper position. Wound dehiscence—where the surgical incision reopens—can occur. Components of the device might malfunction or break. For heart valves specifically, infection can cause the valve leaflets to become damaged, leading to heart failure symptoms like shortness of breath and leg swelling.^[2]

A particularly challenging aspect of device infections is that they can sometimes be present without causing obvious symptoms, especially in the early stages or when caused by slow-growing bacteria. This means a patient might have a device infection even though they feel fine and have no visible signs of trouble. This is why the onset of signs and symptoms can occur early after implantation, suggesting contamination during surgery, or can be delayed, sometimes appearing months or even years later.^[2]

Preventing Device-Related Infections

Preventing device-related infections requires attention to multiple factors before, during, and after device placement. While no prevention strategy is perfect, following established guidelines can significantly reduce infection risk.

Antibiotic prophylaxis—giving antibiotics before surgery—is one of the most important preventive measures. Guidelines recommend administering antibiotics that target staphylococcal bacteria, the most common cause of device infections, within one hour before the procedure begins. This creates high antibiotic levels in the tissues and blood during surgery when contamination is most likely to occur. However, the connection between device infections and medical care means patients are also exposed to multi-resistant bacteria, so doctors must choose antibiotics carefully to target the most likely organisms while considering local resistance patterns.^[12]

Surgical technique and the operating environment play crucial roles in prevention. Strict adherence to sterile technique during device implantation helps minimize the introduction of bacteria. This includes thorough skin preparation, proper hand washing and gloving by the surgical team, maintaining a sterile field throughout the procedure, and careful handling of device components. Some centers use specialized antibacterial sleeves or envelopes that wrap around cardiac devices and slowly release antibiotics, and these have shown promise in reducing infection rates.^[11]

Managing modifiable risk factors before surgery can lower infection risk. For patients with diabetes, optimizing blood sugar control in the weeks leading up to device placement helps the immune system function better and promotes proper wound healing. Smoking cessation, even for just a few weeks before surgery, improves tissue oxygenation and healing. Treating any active infections elsewhere in the body before implanting a device prevents bacteria from seeding the new hardware.^[12]

Post-operative care is equally important. Keeping the surgical site clean and dry, monitoring for early signs of infection, and avoiding activities that might stress the incision during the healing period all contribute to infection prevention. Patients should be educated about what symptoms to watch for and when to contact their healthcare provider.

For certain types of devices and situations, additional preventive strategies may be appropriate. These might include using antibiotic-impregnated materials, applying specialized dressings, or scheduling follow-up visits at specific intervals to check for signs of infection before symptoms become obvious.

Despite all these measures, some infections will still occur because it is virtually impossible to eliminate all bacteria during surgery, and devices themselves provide surfaces where bacteria can hide from immune defenses. This reality emphasizes why early detection and prompt treatment are so important when prevention fails.^[12]

How the Body Changes During Device Infection

Understanding what happens inside the body when a device becomes infected helps explain why these infections are so difficult to treat. The process involves complex interactions between the implanted material, invading microorganisms, and the body’s immune and blood clotting systems.

When a foreign object like a medical device is placed in the body, the immune system immediately recognizes it as not belonging there. Even without infection, the body surrounds the implant with immune cells and fibrous tissue in what is called a foreign body response. This response is usually mild and helps isolate the device. However, if bacteria contaminate the device, this same process can inadvertently help the infection by creating an environment where bacteria are partially protected from immune attacks.^[1]

The formation of biofilm is central to device infection pathophysiology. Immediately after a device is implanted, proteins from blood and tissue fluid coat its surface. Bacteria that come into contact with this protein layer can stick to it. Once attached, the bacteria begin producing the extracellular polymeric matrix that defines biofilm. Within this biofilm, bacteria behave very differently than when they are floating freely. They grow more slowly, enter dormant states, and activate genes that make them resistant to antibiotics. The biofilm matrix itself acts as a physical barrier that antibiotics struggle to penetrate.^[5]

The biofilm may act as a filter, trapping minerals or components from the blood serum. Most of the biofilm volume is actually composed of this extracellular polymeric substance rather than bacterial cells. Microscopic examination reveals that the extracellular material appears either as thin strands connecting cells to each other and to the device surface, or as sheets of amorphous material covering the surface. This architecture makes biofilms both tenacious—extremely difficult to remove—and highly resistant to antimicrobial treatment.^[5]

Research has demonstrated just how resistant biofilm bacteria are compared to free-floating bacteria. In laboratory studies, treating biofilm with antibiotic levels far exceeding what would normally kill bacteria resulted in only modest reductions in bacterial counts—a 100-fold decrease—while the same antibiotic dose produced more than a 100-million-fold decrease in free-floating bacteria of the same species. This dramatic difference explains why device infections cannot usually be cured with antibiotics alone.^[5]

The host immune system struggles to fight biofilm infections effectively. Immune cells like neutrophils and macrophages—the body’s infection-fighting warriors—arrive at the infected device but cannot penetrate the biofilm matrix to reach the bacteria inside. This leads to frustrated phagocytosis, where immune cells continuously try and fail to engulf bacteria, releasing inflammatory chemicals that damage surrounding tissues but don’t clear the infection. This chronic inflammation contributes to the loosening of implants, tissue breakdown, and other complications.^[1]

The coagulation system—the body’s blood clotting mechanism—also becomes involved in device infections. Bacteria and their products can activate clotting, leading to small clots forming on and around the device. These clots can harbor bacteria, protecting them further from antibiotics and immune defenses. In cardiac devices with leads running through blood vessels, these infected clots can break off and travel to other organs, causing serious complications.^[1]

For devices like urinary catheters, biofilms may initially contain a single bacterial species, but as the catheter remains in place longer, multiple species colonize it, creating complex multispecies biofilms. Different bacterial species within these biofilms can cooperate, with some species creating conditions that help others survive or producing factors that increase antibiotic resistance for the entire community.^[5]