Nosocomial Infections (Hospital-Acquired Infections)
Nosocomial infections are infections that develop while a person is receiving medical attention. They are also known as healthcare-associated infections (HAI) or hospital-acquired infections. The person will not have this infection on admission but may acquire it in healthcare settings such as hospitals, ambulances, and long-term care facilities.
Nosocomial infections can occur when a pathogen — an organism that can cause disease — spreads to a susceptible host. The Centers for Disease Control and Prevention (CDC) oversee disease prevention. State that some of the many invasive procedures and devices involved in modern healthcare can contribute to the spread of infection. These techniques and devices include:
- prosthetic implants
- implanted medical devices
The causes of nosocomial infections vary. They depend on the type or source of infection, the pathogen that caused it, and whether the infection is viral, fungal, or bacterial. Nosocomial infections affect 3.2% of all hospitalized patients in the United States. Antibiotic and multidrug-resistant organisms have led to further complications and greater numbers of these infections. Because of this, there has been a major effort to detect and control them with infection prevention and control programs.
Nosocomial infections have different symptoms, diagnoses, treatments, and potential complications. Common types of this infection include:
- urinary tract infections (UTIs)
- gastrointestinal infections
This article will discuss the types, risk factors, epidemiology, common pathogens, common sources, common transmission routes, impact, antibiotic resistance, and prevention, control, and management of nosocomial infections.
Nosocomial infections can be classified into different types based on the site of infection, the type of pathogen, and the source or mode of transmission. The US Center for Disease Control and Prevention (CDC) categorizes nosocomial infections broadly into the following 4 most frequent types:
- Central Line-associated Bloodstream Infection (CLABSI): These are the bloodstream infections developed in patients with central venous catheters (catheters inserted in veins for administration of intravenous medications). It is common in patients in ICUs and is one of the major causes of HAI-associated morbidity and mortality globally, with about 12 to 25% mortality rate in the USA in 2020.
- Catheter-associated Urinary Tract infections (CAUTI): These are urinary tract infections (infections developed in the urinary tract) in persons with indwelling urinary catheters. It is the most common form of HAIs and is the prime cause of secondary bloodstream infections. A major case of complicated UTI cases is associated with urinary catheterization.
- Surgical Site Infections (SSI): These are the infections developed in or around the site where surgery was done within 30 days of surgery. The infection can be superficial or limited to the epidermal layer (Superficial SSI), deep beneath the incision area in muscle (Deep Incisional SSI), or infecting inner organs (Space SSI).
- Ventilator-associated Pneumonia (VAP): Pneumonia is the second most common nosocomial infection after UTI seen in patients with critical illness, and the associated mortality rate may be up to 50%. If a patient receiving mechanical ventilator support develops pneumonia after 48 hours of being incubated, then pneumonia can be defined as ventilator-associated pneumonia.
Besides there are other types of nosocomial infections, such as:
- Gastroenteritis/Gastrointestinal Infections: Gastrointestinal infections seen in patients after at least 48 hours of admission, during their stay in the healthcare facility, or within 3 days of being discharged from the healthcare facility can be defined as nosocomial gastroenteritis.
- Nosocomial Skin Infection: Infection of the skin due to exposure to pathogenic microorganisms in a healthcare facility is called nosocomial skin infection. After a long hospital stay or use of antimicrobials and/or other medications making the immune system weak, the normal skin flora of the patients begins to develop several forms of skin infections like rashes, ulcers, cellulitis, folliculitis, pyogenic and non-pyogenic wounds, etc. The most common causative is Staphylococcus spp., either normal flora or Staph transmitted from other patients or, most commonly, healthcare workers.
- Non-catheter-associated Bloodstream Infections and Urinary Tract Infections: These are bloodstream infections and urinary tract infections seen in hospitalized (including recently discharged) patients without any catheterization.
- Non-ventilator-associated Pneumonia (NVAP)and other Respiratory Tract Infections: In hospitalized patients without ventilator support, several forms of respiratory tract infections are seen; all these RTIs fall under this category. While VAP is associated primarily with aerobes, the non-ventilator-associated RTIs are caused by aerobes, anaerobes, as well as respiratory viruses.
Nosocomial infections can also be classified on the basis of associated pathogenic microorganisms into bacterial, fungal, and viral nosocomial infections.
Some possible additional sentences to conclude point 2 are:
- Each type of nosocomial infection has its own risk factors, symptoms, diagnosis, treatment, and prevention strategies that will be discussed later in this article.
- The type and severity of nosocomial infection depend on various factors such as the patient`s condition, the healthcare setting, the pathogen involved, and the source or mode of transmission.
- Understanding the different types of nosocomial infections can help healthcare workers and patients to identify and prevent them effectively.
Nosocomial infections can affect anyone who receives medical care, but some people are more vulnerable than others. The following are some of the common risk factors associated with the development of nosocomial infections :
- Immunocompromisation: Patients with weakened immune systems due to diseases such as HIV, cancer, diabetes, or organ transplantation, or due to medications such as steroids, chemotherapy, or immunosuppressants, are more likely to develop nosocomial infections than patients with healthy immune systems. They are also more prone to severe complications and mortality from these infections.
- Invasive medical procedures and devices: Patients who undergo surgeries, catheterization, ventilation, dialysis, endoscopy, or implantation of medical devices are at higher risk of introducing pathogens into their bodies through the skin, mucous membranes, or bloodstream. These procedures and devices can also damage the natural barriers and defenses of the body and create a favorable environment for microbial growth and biofilm formation.
- Prolonged use of antimicrobials: Patients who receive antibiotics or antifungals for a long time or without proper indication can disrupt their normal flora and increase the risk of colonization and infection by resistant or opportunistic pathogens. Antimicrobials can also suppress the immune system and impair its ability to fight infections.
- Prolonged hospitalization: Patients who stay in the hospital for a long time are more exposed to pathogens from the environment, other patients, staff, visitors, or medical equipment. They also have more chances of undergoing invasive procedures or receiving antimicrobials that can increase their susceptibility to nosocomial infections.
- Use of contaminated medical equipment: Medical equipment such as thermometers, stethoscopes, blood pressure cuffs, pulse oximeters, syringes, needles, gloves, masks, or gowns can be sources of transmission of pathogens if they are not properly cleaned, disinfected, sterilized, or disposed of after use. This equipment can carry pathogens from one patient to another or from the staff to the patients.
- Contact with other patients and healthcare workers: Patients who share rooms, beds, toilets, or utensils with other patients can acquire pathogens from them through direct or indirect contact. Similarly, healthcare workers who do not practice good hand hygiene or use appropriate personal protective equipment (PPE) can transmit pathogens from one patient to another or from themselves to the patients.
- Chronic diseases: Patients who have chronic diseases such as COPD, heart failure, kidney failure, liver cirrhosis, or diabetes mellitus are more susceptible to nosocomial infections because these conditions can impair their immune system and organ function and make them more dependent on invasive procedures and devices.
- Age: Age is also a factor that influences the risk of nosocomial infections. Elderly people and neonates are more vulnerable than children and adults because they have weaker immune systems and more comorbidities that can affect their ability to fight infections.
Is this helpful? Do you want me to write more points? 😊
Nosocomial infections are a global public health problem that affects patients in any healthcare setting, both in developed and developing countries. According to the World Health Organization (WHO), about 7% of patients in developed countries and 10% of patients in developing countries acquire at least one nosocomial infection during their hospital stay. Among hospitalized patients, those in intensive care units (ICUs), burn units, surgical wards, and neonatal units are at higher risk of nosocomial infections. The most common types of nosocomial infections are urinary tract infections, surgical site infections, bloodstream infections, and pneumonia.
The epidemiology of nosocomial infections varies by region, country, hospital, and ward. Several factors influence the occurrence and spread of nosocomial infections, such as the type and quality of healthcare services, the availability and use of infection prevention and control measures, the surveillance and monitoring systems, the prevalence and transmission of antimicrobial-resistant pathogens, and the patient characteristics and comorbidities. Therefore, it is important to conduct regular and systematic surveillance of nosocomial infections to estimate their burden, identify their causes and sources, monitor their trends and patterns, and evaluate the effectiveness of preventive and control strategies.
Several studies have reported the epidemiology of nosocomial infections in different parts of the world. For example, a systematic review and meta-analysis by Raoofi et al. (2023) estimated the global prevalence of nosocomial infections to be 0.14%, with the highest rate in Africa (0.27%) and the lowest rates in America and Western Pacific regions (0.08% each). The study also found that Escherichia coli was the most common pathogen causing nosocomial infections, followed by coagulase-negative staphylococci, Staphylococcus spp., and Pseudomonas aeruginosa. Moreover, the study reported that transplant units, neonatal units, and ICUs had the highest rates of nosocomial infections among hospital wards and that men were more likely to acquire nosocomial infections than women.
Another study by Khan et al. (2017) reviewed the epidemiology of nosocomial infections in Asia-Pacific countries and found that the overall prevalence ranged from 2.5% to 14.8%, with urinary tract infections being the most common type, followed by surgical site infections, pneumonia, and bloodstream infections. The study also identified several risk factors for nosocomial infections in this region, such as immunosuppression, invasive procedures, prolonged hospitalization, antimicrobial use, contaminated medical devices, contact with other patients and healthcare workers, chronic diseases, and age.
A third study by Vincent et al. (2009) conducted a one-day point prevalence survey of nosocomial infections in ICUs across 75 countries and found that 51% of ICU patients had at least one nosocomial infection. The most frequent sites of infection were the respiratory tract (64%), bloodstream (37%), urinary tract (12%), and surgical site (10%). The most common pathogens were Staphylococcus aureus (20%), Pseudomonas spp. (19%), Acinetobacter spp. (15%), Enterobacteriaceae (15%), Candida spp. (10%), and Enterococcus spp. (7%). The study also reported that 71% of ICU patients received antibiotics on the day of the survey.
These studies illustrate the diversity and complexity of the epidemiology of nosocomial infections worldwide. They also highlight the need for more research and data on this topic to inform policy-making and practice improvement in healthcare settings. Nosocomial infections are preventable and controllable with appropriate measures such as hand hygiene, environmental disinfection, isolation precautions, antimicrobial stewardship, immunization, education, surveillance, and feedback. By understanding the epidemiology of nosocomial infections better, we can reduce their impact on patient`s health outcomes and healthcare costs.
: International Study of the Prevalence and Outcomes of Infection ... - PubMed
Nosocomial infections can be caused by various microorganisms, such as bacteria, fungi, viruses, and parasites. These pathogens can vary depending on different patient populations, medical facilities, and environmental factors. However, some pathogens are more commonly associated with nosocomial infections than others. Here are some of the most common pathogens responsible for nosocomial infections and the types of infections they cause.
Bacteria are the most common pathogens responsible for nosocomial infections. Some belong to the natural flora of the patient and cause infection only when the immune system of the patient becomes prone to infections. Others are transmitted from the environment, other patients, or healthcare workers. Some of the most common bacterial pathogens associated with nosocomial infections are:
- Staphylococcus aureus: This bacterium can cause various types of nosocomial infections, such as surgical site infections (SSI), central line-associated bloodstream infections (CLABSI), ventilator-associated pneumonia (VAP), and catheter-associated urinary tract infections (CAUTI). It can also cause skin and soft tissue infections, such as cellulitis and abscesses. Some strains of S. aureus are resistant to methicillin and other antibiotics, making them more difficult to treat. These are called methicillin-resistant S. aureus (MRSA).
- Escherichia coli: This bacterium is normally found in the intestinal tract of humans and animals, but it can cause infection when it enters other sites of the body. It is the most common cause of CAUTI and a frequent cause of CLABSI and SSI. It can also cause gastrointestinal infections, such as diarrhea and colitis. Some strains of E. coli produce toxins that can cause severe complications, such as hemolytic uremic syndrome (HUS). Some strains of E. coli are also resistant to multiple antibiotics, such as carbapenems.
- Enterococcus spp.: These bacteria are also part of the normal intestinal flora, but they can cause infection when they spread to other sites of the body. They are common causes of CLABSI, CAUTI, SSI, and intra-abdominal infections. They can also cause endocarditis, meningitis, and osteomyelitis. Some strains of Enterococcus spp. are resistant to vancomycin and other antibiotics, making them more difficult to treat. These are called vancomycin-resistant enterococci (VRE).
- Pseudomonas aeruginosa: This bacterium is widely distributed in the environment, such as soil, water, and plants. It can cause infection in patients with compromised immune systems or underlying lung diseases. It is a common cause of VAP, CLABSI, SSI, and skin and soft tissue infections. It can also cause ear infections, eye infections, and septic shock. P. aeruginosa is notorious for its ability to form biofilms on medical devices and resist many antibiotics.
- Klebsiella spp.: These bacteria are also part of the normal intestinal flora, but they can cause infection when they spread to other sites of the body. They are common causes of CAUTI, CLABSI, VAP, and SSI. They can also cause pneumonia, meningitis, wound infections, and liver abscesses. Some strains of Klebsiella spp. Produce enzymes that can inactivate carbapenems and other antibiotics, making them more difficult to treat. These are called carbapenem-resistant Klebsiella spp. (CRKP) .
Fungi are less common than bacteria as causes of nosocomial infections, but they can be more difficult to diagnose and treat. They mainly infect immunocompromised patients or patients with severe underlying diseases or invasive devices. Some of the most common fungal pathogens associated with nosocomial infections are:
- Candida spp.: These fungi are part of the normal flora of the skin and mucous membranes, but they can cause infection when they overgrow or invade deeper tissues or organs. They are common causes of CLABSI, CAUTI, SSI, and intra-abdominal infections. They can also cause oral thrush, esophagitis,
vaginitis, endocarditis, meningitis, and disseminated candidiasis. Some strains of Candida spp. are resistant to fluconazole and other antifungal agents.
- Aspergillus spp.: These fungi are widely distributed in the environment, such as soil,
compost, plants, and air ducts. They can cause infection in patients with compromised immune systems or underlying lung diseases. They are common causes of VAP,
and invasive pulmonary aspergillosis. They can also cause allergic bronchopulmonary aspergillosis,
and disseminated aspergillosis.
are difficult to treat with antifungal agents
- Mucorales: These fungi are also widely distributed in the environment
such as soil
decaying organic matter
They can cause infection in patients with compromised immune systems.
They are common causes of rhinocerebral mucormycosis.
A life-threatening infection that affects the nose
They can also cause pulmonary mucormycosis.
and disseminated mucormycosis
are resistant to many antifungal agents
Viruses are less common than bacteria and fungi as causes of nosocomial infections.
But they can be more contagious and difficult to prevent
They mainly infect patients with respiratory or gastrointestinal symptoms or patients who have contact with infected individuals or contaminated surfaces or equipment.
Some of the most common viral pathogens associated with nosocomial infections are:
- Noroviruses: These viruses are highly contagious and can cause acute gastroenteritis in patients who ingest contaminated food or water or have contact with infected individuals or surfaces
They can cause nausea.
Noroviruses are resistant to many disinfectants and can persist on surfaces for long periods of time.
- Rotaviruses: These viruses are also highly contagious and can cause acute gastroenteritis in patients who ingest contaminated food or water or have contact with infected individuals or surfaces
They can cause similar symptoms as noroviruses but may also cause fever and respiratory symptoms in some cases.
Rotaviruses are more common in children than adults and can be prevented by vaccination.
- Influenza viruses: These viruses can cause respiratory tract infections in patients who inhale contaminated droplets or aerosols or have contact with infected individuals or surfaces
They can cause fever.
Influenza viruses can also lead to complications such as pneumonia.
and sepsis in some cases
Influenza viruses mutate frequently and require annual vaccination for prevention.
- Respiratory syncytial virus (RSV): This virus can cause lower respiratory tract infections in patients who inhale contaminated droplets or aerosols or have contact with infected individuals or surfaces
It can cause bronchiolitis
(inflammation of the small airways)
(inflammation of the lungs)
in infants and young children
It can also cause upper respiratory tract symptoms such as rhinitis
(inflammation of the nose)
(inflammation of the throat)
in older children and adults
RSV is more prevalent in winter months and can be prevented by prophylactic antibodies for high-risk groups
- Herpes simplex virus (HSV): This virus can cause oral or genital herpes in patients who have contact with infected individuals or surfaces
It can cause painful blisters or ulcers on the lips
that recur periodically
HSV can also cause encephalitis
(inflammation of the brain)
or neonatal herpes
(infection in newborns)
in some cases
HSV is latent in nerve cells and cannot be cured but can be treated with antiviral
Nosocomial infections can occur when a pathogen spreads from a source or reservoir to a susceptible host. A source or reservoir is a place where the pathogen can survive and multiply. There are various sources or reservoirs of pathogens associated with nosocomial infections, such as:
- Healthcare setting staff (including both clinical and non-clinical personnel): They can carry pathogens on their skin, hair, clothing, or equipment and transmit them to patients or other staff members through direct or indirect contact. They can also be asymptomatic carriers of pathogens that can cause nosocomial infections.
- Environmental aspects like surface, water, food, air, patient room, bathroom, basin, bedding, door knobs, medical devices, etc.: They can be contaminated with pathogens from various sources, such as patients, staff, visitors, animals, or hospital wastes. Pathogens can survive on these environmental aspects for different periods of time and can be transferred to patients or staff through contact, ingestion, inhalation, or aerosolization.
- Patients (normal flora of patients themselves or microbiome from other patients): They can harbor pathogens as part of their normal flora or acquire them from other sources. These pathogens can cause nosocomial infections in the same patient or spread to other patients through direct or indirect contact. Patients can also develop opportunistic infections when their normal flora is disrupted by factors such as antibiotic use, immunosuppression, or invasive procedures.
- Visiting members of patients: They can bring pathogens from outside the healthcare setting and transmit them to patients or staff through direct or indirect contact. They can also be asymptomatic carriers of pathogens that can cause nosocomial infections.
- Hospital wastes: Can contain pathogens from various sources, such as patients, staff, visitors, animals, or medical devices. These pathogens can contaminate the environment or infect people who handle or dispose of the wastes.
- Animals like pests, insects, and others in the healthcare facility: They can carry pathogens on their bodies or excreta and transmit them to patients or staff through direct or indirect contact. They can also act as vectors for some pathogens that can cause nosocomial infections.
Preventing and controlling nosocomial infections requires identifying and eliminating the sources or reservoirs of pathogens in the healthcare setting. This can be achieved by implementing various measures such as:
- Practicing good hand hygiene by washing hands with soap and water or using alcohol-based hand rubs before and after contact with patients, staff, visitors, animals, or environmental aspects.
- Use personal protective equipment (PPE) such as gloves, masks, gowns, goggles, etc., when handling patients, staff, visitors, animals, environmental aspects, or hospital wastes that may be contaminated with pathogens.
- Cleaning and disinfecting environmental aspects such as surfaces, water, food, air, patient room, bathroom, basin, bedding, door knobs, medical devices, etc., regularly and properly using appropriate methods and agents.
- Isolating patients who have infectious diseases or are at high risk of acquiring nosocomial infections from other patients and staff.
- Educating patients and visitors about the risks and prevention of nosocomial infections and encouraging them to follow infection control measures such as hand hygiene and PPE use.
- Managing hospital wastes safely and effectively by segregating them according to their types and disposing of them in designated containers and areas.
- Controlling pests and insects in the healthcare facility by using appropriate methods and agents.
By reducing the sources or reservoirs of pathogens associated with nosocomial infections in the healthcare setting,
the risk of transmission and infection can be minimized.
Nosocomial infections can be transmitted through various routes in the healthcare setting. The main routes of transmission are:
- Contact transmission: This is the most important and frequent mode of transmission of nosocomial infections. It involves direct or indirect contact with an infected or colonized person or object. Direct contact transmission occurs when there is a physical transfer of microorganisms between a susceptible host and an infected or colonized person, such as during patient care activities that require direct personal contact. Indirect contact transmission occurs when a susceptible host touches a contaminated intermediate object, such as medical equipment, instruments, dressings, gloves, or needles.
- Droplet transmission: This occurs when respiratory droplets containing microorganisms from the infected person are propelled a short distance (usually less than 1 meter) through the air and deposited on the mucous membranes of the host. Droplets are generated from the source person mainly by coughing, sneezing, speaking, or during certain medical procedures, such as bronchoscopy or intubation. Examples of pathogens transmitted by droplet route include influenza virus, respiratory syncytial virus, and Streptococcus pneumoniae.
- Airborne transmission: This involves the dissemination of infectious agents over long distances via contaminated air. The infectious agents can be airborne droplet nuclei (small-particle residue of evaporated droplets containing microorganisms that remain suspended in the air for long periods of time) or dust particles containing the infectious agent. Microorganisms carried in this manner can be dispersed widely by air currents and may be inhaled by a susceptible host within the same room or over a longer distance from the source patient, depending on environmental factors. Therefore, special air handling and ventilation are required to prevent airborne transmission. Examples of pathogens transmitted by airborne route include Mycobacterium tuberculosis, varicella-zoster virus, and measles virus.
- Common vehicle transmission: This applies to microorganisms transmitted to the host by contaminated items, such as food, water, medications, devices, and equipment. These items can serve as vehicles for multiple exposures of different hosts to the same source of infection. Examples of pathogens transmitted by common vehicle routes include Salmonella spp., hepatitis A virus, and norovirus.
- Vector-borne transmission: This occurs when vectors such as mosquitoes, flies, rats, and other vermin transmit microorganisms to the host. These vectors can carry pathogens from one host to another or from a contaminated environment to a host. Examples of pathogens transmitted by vector-borne route include Plasmodium spp., Leishmania spp., and Rickettsia spp.
The prevention and control of nosocomial infections depend on interrupting these routes of transmission by implementing appropriate infection control measures.
Nosocomial infections, also known as hospital-acquired infections (HAIs), are infections that patients acquire during their stay in a healthcare facility. They can affect any part of the body, such as the bloodstream, urinary tract, surgical site, respiratory tract, gastrointestinal tract, and skin. They can be caused by various types of microorganisms, such as bacteria, fungi, viruses, and parasites.
Nosocomial infections have a significant impact on patient outcomes, as they can lead to:
- Increased morbidity and mortality: Nosocomial infections can worsen the underlying condition of the patient, cause secondary complications, and increase the risk of death. According to the World Health Organization (WHO), nosocomial infections are the most frequent adverse event in healthcare delivery and are associated with 5-10% mortality in high-income countries and 15-40% mortality in low- and middle-income countries. A study by CHEST found that nosocomial infections following cardiac surgery were associated with prolonged lengths of hospitalization, the development of multiorgan dysfunction, and increased hospital mortality.
- Prolonged hospital stay: Nosocomial infections can delay the recovery and discharge of the patient, resulting in longer hospitalization and higher occupancy rates. This can also increase the exposure of the patient to other potential pathogens and reduce the availability of beds for other patients. According to Pharmacy Times, nosocomial infections can extend hospital stays by an average of 17.6 days.
- Increased cost of treatment: Nosocomial infections can increase the cost of treatment for both the patient and the healthcare system, as they require additional diagnostic tests, medications, procedures, and interventions. They can also increase the indirect costs related to lost productivity, disability, and litigation. According to Medical News Today, nosocomial infections cost the US healthcare system an estimated $28-$45 billion per year.
- Antimicrobial resistance: Nosocomial infections are often caused by antimicrobial-resistant organisms that are difficult to treat and can spread to other patients and settings. Antimicrobial resistance can limit the effectiveness of available drugs and increase the risk of treatment failure and death. According to ScienceDirect, nosocomial infections are one of the major drivers of antimicrobial resistance worldwide.
Nosocomial infections are a serious threat to patient safety and quality of care. They can be prevented and controlled by implementing effective infection prevention and control measures, such as hand hygiene, environmental cleaning, sterilization of equipment, isolation of infected patients, rational use of antimicrobials, immunization, surveillance, and education.
Antibiotic resistance is the ability of bacteria to survive and grow in the presence of antibiotics that would normally kill or inhibit them. Antibiotic resistance is a major global threat that poses serious challenges to the treatment of infectious diseases, especially nosocomial infections (NIs), which are infections acquired in healthcare settings such as hospitals, clinics, nursing homes, etc. NIs are often caused by multidrug-resistant (MDR) bacteria, which are resistant to more than one class of antibiotics and can spread rapidly among patients and healthcare workers. NIs can increase the morbidity, mortality, length of hospital stay, and cost of treatment for patients, as well as the risk of outbreaks and epidemics.
The main causes of antibiotic resistance in NIs are the overuse and misuse of antibiotics, the lack of infection prevention and control measures, the inadequate surveillance and monitoring of antibiotic resistance, and the insufficient research and development of new antibiotics. These factors create selective pressure for bacteria to evolve resistance mechanisms that enable them to survive and multiply in the presence of antibiotics.
There are different mechanisms by which bacteria can acquire antibiotic resistance, such as:
- Mutation: Bacteria can mutate their own genes that encode for antibiotic targets, enzymes, or transporters, resulting in reduced susceptibility or resistance to antibiotics. For example, some bacteria can mutate their penicillin-binding proteins (PBPs) to avoid the binding of beta-lactam antibiotics, such as methicillin-resistant Staphylococcus aureus (MRSA).
- Horizontal gene transfer: Bacteria can exchange genetic material with other bacteria through plasmids, transposons, integrons, or bacteriophages, resulting in the acquisition of resistance genes that encode for antibiotic-modifying enzymes, efflux pumps, or alternative targets. For example, some bacteria can acquire genes that encode for extended-spectrum beta-lactamases (ESBLs), carbapenemases, or vancomycin resistance.
- Biofilm formation: Bacteria can form biofilms on surfaces or medical devices, such as catheters, implants, or ventilators, resulting in increased tolerance or resistance to antibiotics due to reduced penetration, altered metabolism, or enhanced expression of resistance genes. For example, some bacteria can form biofilms on central venous catheters and cause bloodstream infections.
Some examples of MDR bacteria that cause NIs are:
- ESKAPE pathogens: These are a group of six bacteria that are responsible for most NIs and have high levels of antibiotic resistance. They include Enterococcus faecium (vancomycin-resistant enterococci), Staphylococcus aureus (MRSA), Klebsiella pneumonia (carbapenem-resistant Klebsiella pneumoniae), Acinetobacter baumannii (carbapenem-resistant Acinetobacter baumannii), Pseudomonas aeruginosa (carbapenem-resistant Pseudomonas aeruginosa), and Enterobacter spp. (pan-drug resistant Enterobacter spp.) .
- Candida spp.: These are fungi that cause invasive candidiasis, which is a serious form of NI that affects the bloodstream or internal organs. Some Candida spp., such as Candida auris, have developed resistance to multiple classes of antifungal drugs, such as azoles, echinocandins, and polyenes.
- Clostridioides difficile: This is a bacterium that causes pseudomembranous colitis, which is a severe form of diarrhea associated with antibiotic use. C. difficile produces toxins that damage the intestinal lining and cause inflammation. Some strains of C. difficile have become resistant to metronidazole and vancomycin, which are the main drugs used to treat this infection.
The implications of antibiotic resistance in NIs are:
- Reduced treatment options: Patients with NIs caused by MDR bacteria may have limited or no effective antibiotics available for their treatment, resulting in increased morbidity and mortality.
- Increased health care costs: Patients with NIs caused by MDR bacteria may require more intensive care, longer hospital stays, additional diagnostic tests, isolation precautions, and alternative or more expensive antibiotics for their treatment, resulting in increased health care costs.
- Increased transmission risk: Patients with NIs caused by MDR bacteria may act as reservoirs or sources of transmission for other patients or healthcare workers in the same or different healthcare settings, resulting in an increased risk of outbreaks and epidemics.
- Prevention, Control, and Management of Nosocomial Infections
Nosocomial infections are a major threat to patient safety and quality of care in healthcare settings. They can cause increased morbidity, mortality, length of stay, and cost of treatment. Therefore, it is essential to implement effective strategies to prevent, control, and manage nosocomial infections. Some of the recommended measures are :
- Practicing good hand hygiene by washing hands with soap and water or using alcohol-based hand rubs before and after contact with patients, equipment, or the environment. Hand hygiene is the most important and simplest way to prevent the transmission of pathogens.
- Using personal protective equipment (PPE) such as gloves, masks, gowns, and eye protection when indicated to protect oneself and others from exposure to infectious agents. PPE should be worn correctly and disposed of properly after use.
- Cleaning and disinfecting surfaces and equipment that are frequently touched or contaminated with blood or body fluids. This includes bed rails, tables, chairs, door handles, faucets, keyboards, monitors, stethoscopes, thermometers, etc. Disinfectants should be used according to the manufacturer`s instructions and contact time.
- Sterilizing or high-level disinfecting reusable medical devices such as endoscopes, surgical instruments, catheters, etc., before each use. Sterilization or high-level disinfection should be done following the manufacturer`s guidelines and quality assurance protocols.
- Minimizing the use of invasive devices such as catheters, central lines, ventilators, etc., and removing them as soon as possible. Invasive devices can introduce or facilitate the entry of pathogens into the body and increase the risk of device-related infections. If invasive devices are necessary, they should be inserted and maintained using an aseptic technique and following evidence-based guidelines.
- Implementing antimicrobial stewardship programs to optimize the use of antibiotics and prevent the emergence and spread of antimicrobial resistance. Antimicrobial stewardship involves selecting the appropriate antibiotic, dose, duration, and route of administration for each patient based on clinical evidence and local susceptibility patterns. It also involves reviewing antibiotic therapy regularly and de-escalating or discontinuing it when appropriate.
- Vaccinating patients and healthcare workers against preventable diseases such as influenza, pneumococcal pneumonia, hepatitis B, etc. Vaccination can reduce the incidence and severity of infections and prevent outbreaks in healthcare settings.
- Educating patients and healthcare workers about nosocomial infections, their modes of transmission, and their prevention and control measures. Education can increase awareness, knowledge, attitude, and behavior change among patients and healthcare workers and improve compliance with infection prevention practices.
- Conducting surveillance and monitoring of nosocomial infections using standardized definitions, methods, and tools. Surveillance can help identify the types, rates, trends, sources, and risk factors of nosocomial infections and evaluate the effectiveness of prevention and control interventions. Surveillance data should be analyzed regularly and reported to relevant stakeholders for feedback and action.
- Implementing infection prevention and control policies and procedures based on national and international guidelines and best practices. Policies and procedures should be updated periodically to reflect the latest evidence and recommendations. They should also be communicated clearly and consistently to all healthcare workers and enforced by designated infection prevention and control personnel.
By following these measures, nosocomial infections can be prevented or reduced significantly in healthcare settings. This can improve patient outcomes, reduce healthcare costs, enhance patient satisfaction, and save lives.
We are Compiling this Section. Thanks for your understanding.