Basic Principles of Infection Prevention and Control

Basic Principles of Infection Prevention and Control

Charles Edmiston Jr

Gwen Borlaug

Health care-associated infections (HAIs), formerly called nosocomial infections, are infections that sometimes occur among patients receiving medical care. They are associated with the use of invasive medical devices such as central venous catheters (CVC), urinary catheters, and mechanical ventilators and can also occur following surgical and other invasive procedures. The four major HAI types of concern include central line-associated bloodstream infections (CLABSI); catheter-associated urinary tract infections (CAUTI); surgical site infections (SSIs); and ventilator-associated adverse events (VAE), which include ventilator-associated pneumonia (VAP). Exposure to antibiotic agents also puts patients at risk of acquiring Clostridium difficile infections (CDI) and infections caused by multidrug-resistant organisms (MDRO) such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and carbapenem-resistant gram-negative bacteria.

The HAIs are associated with increased morbidity, mortality, and higher cost of health care delivery.1 During the 1960s, hospitals developed infection control programs to conduct HAI surveillance and to implement measures to address these adverse events. By the mid-1970s, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) included a standard that required hospitals to develop and implement infection control programs as part of the accreditation process. At that time, approximately 30% of HAIs were considered preventable, based on a study conducted by the Centers for Disease Control and Prevention (CDC).2 Today, because the science of prevention has advanced, we now know much larger proportions of HAIs are preventable than once thought. Furthermore, attitudes among providers, health care quality experts, infection preventionists, and public health officials toward HAIs have changed. Once considered inevitable consequences of providing health care, HAIs are currently viewed as unacceptable and largely preventable outcomes of patient care.


During 2011, the CDC conducted a multistate point-prevalence survey to estimate the occurrence of HAIs among hospital patients, using the surveillance definitions from the National Healthcare Safety Network (NHSN), the national HAI database maintained by the CDC. The study revealed that approximately 650 000, or 4% of hospital patients, acquired 722 000 HAIs, and 75 000 patients died with an HAI during their hospital stay. The most prevalent types of HAI were non-VAP (157 000) and SSIs (157 000), each of which comprised 22% of the total number of HAIs identified in the survey. C difficile was the most prevalent health care-associated pathogen, with approximately 12% of HAIs caused by this organism, compared to 7% of HAIs caused by MRSA.

This study highlights the changing epidemiology of HAIs. Historically, device-associated infections have been the most prevalent type of HAI; however, in this study, they comprised only 25% of HAIs, with CDI, other gastrointestinal infections, and non-VAP comprising half of all reported HAIs. Modern-day health care infection prevention efforts must include strategies to prevent these types of HAIs in addition to the traditional focus on device-associated and invasive procedure-associated infections.3


In addition to posing threats to patient safety and favorable patient care outcomes, HAIs exert significant financial burdens on the health care system. A 2009 report estimated that HAIs can add up to $4.5 billion in excess health care costs annually in the United States. This figure does not account for HAIs occurring outside of hospital settings.4
The CDC estimated HAI costs that same year to range from $5.7 to $6.8 billion annually. Cost varied by HAI type, with CAUTI the least costly to treat and SSI and VAP the most costly HAI types to treat (Table 49.1).5

TABLE 49.1 Aggregate attributable patient hospital costs by site of infectiona

Type of HAI

Range of Cost Estimates (Based on 2007 Consumer Price Index)


$11 874-$34 670


$7288-$29 156


$19 633-$28 508





Abbreviations: CAUTI, catheter-associated urinary tract infections; CDI, Clostridium difficile infections; CLABSI, central line-associated bloodstream infections; HAI, health care-associated infection; SSI, surgical site infection; VAP, ventilator-associated pneumonia.

aData from Scott.5


During the mid-2000s, as health care leaders, public health officials, and political leaders recognized that HAIs continued to be significant patient safety and public health issues, a national collective will to intensify HAI reduction and elimination efforts resulted in a national call to action to eliminate all preventable HAIs through broad application of evidence-based prevention strategies. Congressional leaders called on the US Department of Health and Human Services (HHS) to escalate national HAI prevention efforts, and in response to this directive, HHS convened the Federal Steering Committee for the Prevention of Health Care-Associated Infections to coordinate HAI prevention efforts across federal government agencies. Members of the Steering Committee included clinicians, scientists, and public health officials representing myriad private and government entities.

During 2009, the Steering Committee issued the National Action Plan to Prevent Health Care-Associated Infections: Roadmap to Elimination, which outlined a phased approach to expand HAI prevention beyond acute care facilities. Phase 1 focused on preventing the most prevalent HAIs in hospital settings. Phase 2 focused on reducing HAIs in ambulatory surgery centers (ASCs) and dialysis centers and increasing influenza vaccination among health care personnel. Phase 3 described strategies to address HAIs in long-term care facilities (LTCF). Each phase included goals and metrics for measuring progress toward reaching those goals by December 2013. New targets for HAI reduction have been set for 2020, (Table 49.2) using the 2015 national baseline determined by national data obtained from the NHSN.6

TABLE 49.2 2020 National health care-associated infection prevention plan targetsa

Measure (Data Sources)

2020 Target


50% Reduction in the national SIRb


25% Reduction in the national SIR

Invasive MRSA infections (NHSN/EIP)

50% Reduction in the national SIR

Facility onset MRSA (NHSN)

50% Reduction in the national SIR


30% Reduction in the national SIR


30% Reduction in the national SIR

CDI hospitalizations (HCUP)

30% Reduction in the national SIR

Abbreviations: CAUTI, catheter-associated urinary tract infections; CDI, Clostridium difficile infections; CLABSI, central line-associated bloodstream infections; EIP, emerging infections program; HCUP, health care cost and utilization project; MRSA, methicillin-resistant Staphylococcus aureus; NHSN; National Healthcare Safety Network; SIR, standardized infection ratio; SSI, surgical site infection.

aData from US Department of Health and Human Services.6

b Progress is tracked using the SIR to compare actual health care-associated infection occurrence to predicted occurrence, which is based on risk-adjusted estimates using 2015 national baseline data.

The HHS also directed its key agencies involved in HAI prevention—the CDC, the Centers for Medicare & Medicaid Services (CMS), and the Agency for Healthcare Research and Quality (AHRQ)—to sharpen their focus on HAI prevention. During 2009, the CDC Division of Healthcare Quality Promotion began funding state, territorial, and local health departments to build and strengthen HAI prevention activities in their jurisdictions. Using grants provided under the American Recovery and Reinvestment Act, public health agencies were charged with enhancing HAI surveillance and developing collaborative public and private health partnerships to ensure broad implementation of HAI prevention measures across the population at risk. State health departments were strongly encouraged to work with key partners such as hospital associations and quality improvement organizations (QIO) to develop and implement statewide HAI prevention plans.

The CMS created incentives under the Inpatient Prospective Payment System (IPPS), aimed at improving health care quality by providing financial incentives to hospitals, physicians, and other health care providers.7 The CMS payments to providers were converted during 2008 from a fee-for-service system to value-based purchasing, under which health care institutions are being rewarded for high-quality care and performance improvement with
bonus payments. Conversely, penalties can be imposed if health care institutions fail to achieve certain goals, such as preventing certain conditions among patients during their hospital stay. Some of the conditions that are the basis for penalties include selected HAIs.

The role of AHRQ in HAI prevention is to support research leading to evidence-based HAI prevention measures, to create teaching and training tools for health care professionals to improve health care delivery, and to create systems of measuring performance improvement in health care systems. This agency has funded initiatives to bring science into practice using techniques such as the Comprehensive Unit-based Safety Program (CUSP), aimed at reducing CLABSI occurrence among hospitalized patients.


The CDC 2016 National and State Healthcare-Associated Progress Report revealed that progress was made toward HAI reduction during 2008-2014 (Table 49.3), and during 2014, the national action plan goal for CLABSI reduction was met. Although CAUTI occurrence increased during 2009-2013, progress toward reductions occurred among non-intensive care unit patients, and progress in all settings occurred during 2013-2014. Additionally, SSI following abdominal hysterectomy procedures decreased by 17%, and CDI decreased by 8% from 2011 to 2014. The MRSA bacteremia decreased by 13% from 2011 to 2014.8

TABLE 49.3 Progress toward reduction in occurrence of health care-associated infectionsa,b


Status of Progress


50% Reduction during 2008-2014


No change during 2009-2014

SSI following abdominal hysterectomy

17% Reduction during 2008-2014

SSI following colon surgery

2% Reduction during 2008-2014


8% Reduction during 2011-2014

MRSA bacteremia

13% Reduction during 2011-2014

aProgress was tracked using the standardized infection ratio to compare actual health care-associated infection (HAI) occurrence to predicted occurrence, which was based on risk-adjusted estimates using baseline data (2008 for central line-associated bloodstream infections [CLABSI] and surgical site infection [SSI], 2009 for catheter-associated urinary tract infections [CAUTI], and 2011 for Clostridium difficile infections [CDI] and methicillin-resistant Staphylococcus aureus [MRSA] bacteremia).

bData from Centers for Disease Control and Prevention.8

The HAIs are known to occur outside hospital settings but have not been tracked until 2013, when CMS mandated selected HAI reporting among long-term acute care (LTAC) hospitals and inpatient rehabilitation facilities (IRF). During 2013-2014, CLABSI and CAUTI decreased among LTAC patients by 9% and 11%, respectively, and among IRF patients, CAUTI decreased by 14%.

During 2010, the CDC launched its “Winnable Battles” campaign, in which HAIs were deemed one of six public health priorities because they were leading causes of death and disability but were preventable if known effective prevention strategies were broadly implemented across the population at risk. Despite the successes described earlier, the national focus on HAIs and collaborative efforts among health care providers and public health professionals must continue if future HAI goals are to be met, and health care institutions should continue to prioritize HAI reduction as part of their patient safety and health care quality improvement goals. Infection prevention and control professionals in all health care settings should continue to work with internal and external partners to further drive HAI occurrence toward zero preventable infections.

We subsequently describe the basic infection prevention infrastructure and functions necessary to develop and maintain robust and effective HAI prevention and control programs in health care settings.



The CMS requires hospital infection prevention programs to designate at least one individual as the infection control officer, or infection preventionist. Most hospitals employ a nurse, clinical laboratory scientist, microbiologist, or communicable disease epidemiologist to serve as the infection preventionist. Hospitals must demonstrate this individual’s qualifications through documentation of training and education, experience, or certification. Certification in Infection Prevention and Control (CIC) is obtained through successfully completing a written examination administered by the Certification Board of Infection Control and Epidemiology (CBIC). Certified infection preventionists must renew their certification every 5 years by successfully completing a computer-based self-assessment test.

The Association for Professionals in Infection Control and Epidemiology (APIC) defines core competencies that all infection preventionists should possess to function within the realm of patient safety science and HAI prevention. These core competencies include the ability to identify infectious disease processes, conduct surveillance and epidemiologic investigations, prevent
transmission of infectious agents, support employee and occupational health activities, manage and communicate effectively, provide education, and conduct research.9 Infection preventionists who can demonstrate advanced skills in the APIC future-oriented domains of technology, infection prevention and control, leadership and program management, and performance improvement and implementation science are eligible to become APIC fellows.

In addition to the infection preventionist, the CMS also requires hospitals to designate a leader responsible for the institution’s antibiotic stewardship program. This individual can be a physician, pharmacist, or other hospital staff person responsible for the coordination and oversight of the antibiotic stewardship program.

Although not a CMS requirement, most hospital infection prevention programs include a hospital epidemiologist. This individual is usually an infectious disease physician with training and education in identifying infectious disease outbreaks and understanding the epidemiology of HAIs.10 The role of the hospital epidemiologist has expanded considerably during the past 20 years, to include emergency preparedness, collaboration with public health professionals, education, occupational health, patient safety, and antibiotic stewardship. These individuals may also function as the medical director for the hospital infection prevention program.

The Joint Commission, as well as many state legislatures, directs hospitals to organize infection control committees to oversee the institution’s infection prevention and control program.11 These committees are typically composed of the infection preventionist; hospital epidemiologist; quality resource director; microbiology laboratory staff; pharmacy representatives; risk management, central processing, and environmental services representatives; infectious disease physicians; and providers and managers representing the various patient care services provided by the institution. The purpose of the committees is to oversee all aspects of the hospital infection prevention program, including surveillance, outbreak investigation, policy and procedure development, and education of hospital staff and patients.12

Ambulatory Surgery Center Infection Prevention Program Infrastructure

Following a 2008 outbreak of hepatitis C virus infections at a Las Vegas ASC, it became evident that little was known regarding infection prevention practices in these settings. Thus, the CMS conducted surveys during 2008 among a sample of ASCs using a pilot audit tool focused on assessment of key infection prevention practices such as hand hygiene, injection safety, equipment reprocessing, and environmental cleaning and disinfection.13 At least one lapse in infection prevention practices was found among most facilities. As a result, the CMS added infection prevention requirements to the ASC conditions of participation.

The CMS conditions of participation for ASCs include a requirement for the facility to designate a qualified, licensed health care professional with training in infection control to direct the ASC infection prevention program. If the designated infection control professional is not certified in infection control, evidence of training in infection control methods must be provided.

The facility must also demonstrate the existence of an infection control program and adherence to nationally recognized infection control guidelines. The requirements do not specify the amount of time that must be spent on infection prevention activities, but sufficient time should be allowed to direct an effective infection prevention program.

Components of an ASC infection prevention program must include systems to actively identify postprocedure infections, report notifiable conditions to public health agencies, to train personnel regarding infection prevention strategies, and to comply with current standards for prevention practices such as hand hygiene, safe injection practices, and equipment reprocessing.

Long-Term Care Facility Infection Prevention Program Infrastructure

During October 2016, the CMS issued new requirements for participation for LTCF, the first comprehensive update to health and safety standards for these facilities since 1991. The Final Rule, also called the Mega Rule, aims to improve resident safety and quality care through reduction of hospital readmissions and incidence of HAIs.14

The LTCF must designate an individual who is trained in infection prevention practices to coordinate the facility’s infection prevention program, and antibiotic stewardship programs must be created to develop antibiotic use protocols and systems to monitor antibiotic use. A formal surveillance process to monitor trends in HAI occurrence must also be in place.


Well-designed and executed health care infection prevention programs are successful in reducing device-associated infections such as CLABSI, CAUTI, VAP, and SSI and other invasive procedure-associated infections. They are also aimed at protecting patients and health care personnel from acquiring communicable diseases such as influenza and other respiratory virus infections, gastrointestinal illnesses, and infections with health care-associated pathogens such as CDI and MDRO (eg, MRSA,
carbapenem-resistant Enterobacteriaceae) while receiving or giving health care. Infection prevention program activities can be divided into two main domains: surveillance for HAIs and prevention and control of HAIs.

Surveillance for Health care-Associated Infections

Surveillance is the process of collecting and analyzing data regarding HAIs and other health care-associated events to monitor trends in occurrence and to evaluate the effectiveness of strategies implemented to prevent adverse events and increase positive patient outcomes. Surveillance is the foundation of quality assurance, performance improvement, and prevention activities and is a major activity of the infection preventionist.

Surveillance for all HAIs is not feasible or necessary; thus, infection prevention program activities should include development of annual surveillance plans to prioritize surveillance activities based on the patient populations most at risk of adverse outcomes and that align with the overall quality improvement goals of the institution. Outcomes associated with high-volume and high-risk treatments and procedures should be considered for surveillance.

Surveillance plans must also accommodate federal and state HAI reporting requirements. The CMS value-based purchasing initiative is based in part on submission of selected HAI data to the NHSN, and facilities that fail to complete data entry into that system do not receive full reimbursement from CMS. Most states have also enacted laws requiring hospitals and other health care facilities to report certain HAIs. As of October 2017, 32 states have enacted laws mandating reporting of at least one HAI.15

The NHSN is a national HAI database maintained by the CDC and is the central repository of HAI data used to monitor national, state, and individual facility progress toward HAI reduction. It is also the system used to meet federal and state HAI reporting requirements. More than 17 000 health care facilities including acute care hospitals, LTAC hospitals, psychiatric and rehabilitation hospitals, dialysis centers, ASCs, and skilled nursing facilities participate in NHSN, and more facilities will enroll in the future as HAI surveillance expands to additional health care facilities.16

To track HAI occurrence over time at the national, state, and individual facility level, a standardized infection ratio (SIR) is used to compare the actual number of HAIs occurring at the state or facility level to the predicted number of infections, a risk-adjusted number calculated from NHSN aggregate data. The SIRs that are significantly higher than 1 indicate HAI occurrence worse than predicted, and SIRs significantly lower than 1 indicate HAI occurrence better than predicted. Because SIRs are based on risk-adjusted data, they have replaced the use of incidence rates as the preferred method to track and monitor trends in HAI occurrence over time.

Surveillance includes not only detecting outcomes (eg, HAIs) but also measuring compliance with processes implemented to achieve the desired outcome. Examples of HAI prevention processes that are typically measured to maintain or increase compliance include hand hygiene and influenza vaccination of health care personnel. Process measurement should be an integral part of HAI prevention efforts, and both outcomes and process surveillance data should be disseminated to facility staff, managers, and administrators to motivate further quality improvement.

Although surveillance activities are foundational to successfully reducing HAIs, the modern-day infection preventionist is increasingly burdened with surveillance-related tasks in response to reporting mandates and expansion of health care services and size of facilities. A 2015 survey conducted by the APIC determined that approximately 25% of infection preventionists’ work time is spent conducting surveillance, more than any other single task. This means that less time is available for participating in HAI prevention activities.17 Fortunately, technologic solutions such as installation of electronic medical records systems and development of automated surveillance algorithms have enhanced the efficiency and reliability of surveillance methods. These technologic trends are expected to continue to evolve and further enhance automated surveillance in the future.18

Prevention of Health Care-Associated Infections

Knowledge gained through HAI surveillance, outbreak investigations, and laboratory research has contributed to the dramatic evolution of HAI prevention science since the inception of infection control programs during the 1970s. Organizations such as the APIC and the CDC have developed evidence-based prevention guidelines based on that knowledge to improve patient safety by reducing HAI occurrence.

The Healthcare Infection Control Practices Advisory Committee (HICPAC) is a federal advisory committee that assists the CDC in the development of strategies to prevent device-associated infections and procedure-associated infections; reduce the prevalence of MDRO; prevent transmission of infectious agents among patients and health care personnel; and promote best practices in disinfection and sterilization, environmental infection control, and employee health. These evidence-based strategies are compiled into systematically reviewed guidelines containing multiple recommendations that should be practiced by all health care facilities to prevent HAI occurrence. The recommendations are categorized according to the strength of scientific evidence supporting the strategy or regulatory requirements (Table 49.4).19

TABLE 49.4 Healthcare Infection Control Practices Advisory Committee categorization scheme for strength of evidence of recommendationsa



Category 1A

A strong recommendation supported by high- to moderate-quality evidence suggesting net clinical benefits or harms

Category 1B

A strong recommendation supported by low-quality evidence suggesting net clinical benefits or harms or an accepted practice supported by low- to very low-quality evidence

Category 1C

A strong recommendation required by state or federal regulation

Category 2

A weak recommendation supported by any quality evidence suggesting a trade-off between clinical benefits and harms

No recommendation/unresolved issue

An issue for which there is low- to very low-quality evidence with uncertain trade-offs between the benefits and harms or no published evidence on outcomes deemed critical to weighing the risks and benefits of a given intervention

aData from Centers for Disease Control and Prevention.19

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May 9, 2021 | Posted by in MICROBIOLOGY | Comments Off on Basic Principles of Infection Prevention and Control
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