Access provided by
London Metropolitan University
• To refresh your knowledge of the causes of, and risk factors for, development of surgical site infections
• To be aware of a range of strategies to prevent the development of surgical site infections
• To recognise the importance of adopting a holistic approach to prevention and management of surgical site infections
Surgical site infections (SSIs) are commonly reported healthcare-acquired infections that can have a detrimental effect on patient outcomes and quality of life. SSIs are associated with longer periods of hospitalisation and increased patient morbidity and mortality. A rigorous approach is required to identify and manage the risk of infection across the preoperative, intraoperative and post-operative phases of care. This article describes the causes of, risk factors for development and signs and symptoms of SSIs. The author emphasises the importance of a collaborative, holistic and multidisciplinary approach to the prevention and management of SSIs, which involves the nurse and other healthcare professionals working in partnership with the patient.
Nursing Standard. doi: 10.7748/ns.2023.e12185
Peer reviewThis article has been subject to external double-blind peer review and checked for plagiarism using automated software
Correspondence Conflict of interestNone declared
Walker J (2023) Reducing the risk of surgical site infections. Nursing Standard. doi: 10.7748/ns.2023.e12185
Published online: 11 September 2023
Surgical site infection (SSI) is defined as an infection occurring at an operation site within 30 days of a surgical procedure or within one year when implants, such as joint replacements and/or surgical screws, are used during surgery (World Health Organization (WHO) 2018, Tanner and Melen 2021). This definition is widely used in the literature (Liu et al 2018).
SSIs are the most frequent type of healthcare-associated infections in low and middle-income countries and the second most common type of healthcare-associated infection in Europe and the US (WHO 2018). Reported infection rates vary from 0.4% for knee replacements to 15.4% in bile duct, liver or pancreatic surgery (UK Health Security Agency (UKHSA) 2022). SSIs can have a substantial economic cost for the patient and for health services, and are associated with suboptimal post-operative outcomes, increased morbidity and mortality, longer hospital admissions and higher rates of readmission compared with surgery that does not result in infection (Turner and Migaly 2019, Wan et al 2021).
This article details the causes, risk factors for development of and signs and symptoms of SSIs and discusses a holistic, multifaceted and collaborative approach to their prevention and management.
The skin acts as a physical barrier to prevent pathogens from entering the body, but it is also colonised by bacteria, fungi and viruses, although the composition of these microorganisms varies across the body and with age. Common skin commensals – that is, bacteria that live on the host’s skin – include species of Staphylococcus, Corynebacterium and Propionibacterium (Byrd et al 2018). Infection may occur when the skin barrier is broken or when the balance between commensals and pathogens is disrupted (Alverdy et al 2020). In some instances, bacteria may be transferred from their usual site of colonisation, for example the skin or gut, to a different site such as a surgical wound. This can change the status of a bacterium from commensal to pathogen (Long et al 2022).
Common pathogens associated with SSIs include Escherichia coli, Staphylococcus aureus and Coagulase-negative Staphylococci (CoNS) (UKHSA 2022). When implants are used in surgery, bacteria may adhere to the implant surface and proliferate to cause a biofilm. A biofilm is a community of bacterial cells that are embedded in an extracellular polymeric substance matrix which creates a protective barrier against the host’s immune system and antimicrobial medicines; this means that the bacteria become challenging to detect and irradicate (Simonetti et al 2022). Implant-related infections may be initially asymptomatic and grow slowly, therefore remaining undiagnosed for longer than other SSIs (Arciola et al 2018).
Not all wounds that are contaminated or have a positive microbiology culture will develop an infection (Alverdy et al 2020). The transition from non-infected to infected status is a gradual process dependent on the virulence and microbial burden of the pathogen as well as the patient’s immune response. The International Wound Infection Institute, an international collaboration of healthcare professionals who aim to provide evidence for the prevention, identification and management of wound infections, has developed a five-stage conceptual wound infection continuum that is detailed in Box 1 (Ousey et al 2022, International Wound Infection Institute 2023).
• Contamination – microorganisms are present in the wound but presumed not to be proliferating; no significant host reaction; no delay in wound healing is observed
• Colonisation – microorganisms within the wound are presumed to be undergoing limited proliferation; no significant host reaction; no delay in wound healing is observed
• Local infection – proliferation of microorganisms evokes a host response; delay in wound healing may be observed; local infection is contained (<2cm spread from the wound)
• Spreading infection – infective microorganisms encroach surrounding tissue (>2cm spread from wound); signs and symptoms extend beyond the wound border
• Systemic infection – microorganisms spread throughout the body evoking a host response that affects the body as a whole; signs of systemic infection include sepsis, which requires immediate treatment
(Ousey et al 2022, International Wound Infection Institute 2023)
Nurses should also be aware of the risks posed by multi-drug resistant organisms (MDROs) such as methicillin-resistant S. aureus (MRSA), extended-spectrum beta-lactamase (ESBL) (enzymes that are produced by bacteria such as E. coli and are resistant to antibiotics) or carbapenem-resistant Enterobacteriaceae (CRE). MDROs are resistant to many common antibiotics and can therefore be challenging to treat. The facilitators of microbial resistance include misuse of antimicrobials, lack of clean water and sanitation facilities and substandard infection prevention and control. Identifying patients who have travelled to areas with high rates of MDROs can proactively prevent the spread of these bacteria to other patients and guide appropriate use of antimicrobial interventions (WHO 2021).
Many factors may contribute to a patient’s risk of developing an SSI, therefore nurses should take a multifactorial approach to reducing the infection risk. Factors that influence SSI risk are classified either as patient-related (endogenous) or process-related (exogenous) (WHO 2018).
Endogenous factors include comorbidities, such as inadequately controlled diabetes mellitus, conditions associated with suboptimal tissue perfusion (for example, anaemia, cardiac disease and renal impairment), immune disorders, suboptimal nutritional status (for example, obesity or malnutrition) and smoking (Wan et al 2021, Ousey et al 2022). Older age is a non-modifiable infection risk caused by decreased collagen and a reduced number of dermal blood vessels, which limits oxygen and nutrient delivery to the surgical site (Saeed et al 2022). Exogenous factors include contamination from the environment, contaminated equipment or healthcare workers (WHO 2018).
Considering endogenous and exogenous factors will enable the nurse to develop a proactive and individualised approach to preventing the development of SSIs in patients undergoing surgical procedures.
Strategies aimed at preventing SSIs can be divided into three phases – preoperative, intraoperative and post-operative (National Institute for Health and Care Excellence (NICE) 2020):
• Preoperative phase – focuses on optimising the patient’s physical condition.
• Intraoperative phase – focuses on decontamination of the skin and preventing contamination of the wound with microorganisms, thereby optimising the patient’s physical functioning to aid recovery (Liu et al 2018).
• Post-operative phase – predominantly concerned with wound management.
Preoperative consultations are an ideal opportunity for the nurse to maximise the patient’s nutritional and health status before surgery, thereby promoting a prehabilitation ethos. Prehabilitation empowers the patient to optimise their physical condition before surgery and reduce their risk of developing an SSI. Where malnutrition or a nutritional deficiency has been identified as an SSI risk factor, the patient may benefit from nutrition supplements or dietary enrichment. Important nutrients for optimal wound healing include omega-3 fatty acids, vitamins A and C, carbohydrates and proteins (Gushiken et al 2021). Similarly, where obesity has been identified as an SSI risk factor, the nurse could offer support with weight loss before surgery such as guidance on diet and physical activity (Bray and Ryan 2021).
In some situations, hair removal may be required to expose the operative site, however patients should be advised not to remove hair themselves before surgery due to a potential increase in risk of infection. For example, using a razor may cause skin trauma thus enabling colonisation by microorganisms and increasing the risk of developing an SSI (WHO 2018, NICE 2020). If hair removal is required, the nurse should use electric clippers with a single-use head on the day of surgery (NICE 2020). Tanner and Melen’s (2021) systematic review of preoperative hair removal to reduce surgical site infection identified a small reduction in SSI risk when hair was removed on the day of surgery rather than the day before. Depilating creams may also be used to remove hair from a surgical site, although these can cause local skin irritation (Tanner and Melen 2021).
Patients should bathe or shower before surgery to reduce the bacterial load on the skin or should be assisted with a bed bath if they cannot bathe independently (WHO 2018, NICE 2020). A systematic review by Webster and Osborne (2015) noted that bathing with the antiseptic chlorhexidine did not significantly reduce SSI risk. However, NICE (2020) guidelines suggest that nasal mupirocin (recommended because the nose is the most frequent carriage site for S. aureus) may be used in combination with chlorhexidine body wash where S. aureus is likely to cause an SSI, for example in patients who are known carriers of MRSA and who will be undergoing cardiac or orthopaedic surgery.
• The transition from non-infected to infected status is a gradual process dependent on the virulence and microbial burden of the pathogen and the patient’s immune response
• Considering endogenous and exogenous factors will enable the nurse to develop a proactive and individualised approach to preventing surgical site infections (SSIs) in patients undergoing surgical procedures
• Signs and symptoms of SSI may occur locally at the wound site or systemically
• An understanding of the normal healing process will assist the nurse in early identification of a wound that is not healing following surgery
• It is important that nurses take a holistic approach to preventing and managing SSIs
Intraoperative factors that are known to increase the risk of SSI include open surgery, complex surgery and surgery of extended duration (Wan et al 2021, UKHSA 2022). Therefore, a sterile environment should be maintained during the surgical procedure to limit the risk of spreading microorganisms to the surgical site. This sterile environment encompasses the use of personal protective equipment (PPE) such as masks, gloves and gowns, disinfection of the operating theatre, sterilisation of surgical instruments and limited flow of ‘traffic’, such as staff coming in and out of the operating theatre during surgery (Liu et al 2018). Ventilation systems can be used to filter the air in the operating theatre, thereby reducing the presence of microorganisms in the atmosphere and limiting ingress from other areas.
To reduce the risk of infection from endogenous bacteria on the patient’s epidermis, the skin should be prepared immediately before the surgical incision using an antiseptic skin product that has a broad spectrum of antimicrobial activity. Where possible, an alcohol-based chlorhexidine solution should be used, or aqueous chlorhexidine if the surgical site is next to a mucus membrane to reduce the risk of irritation (NICE 2020). Where chlorhexidine is contraindicated, NICE (2020) recommends the use of a povidone-iodine solution. Prophylactic antibiotics may also be administered intravenously before incision in patients who require a prosthesis or implant, or where the procedure is classed as clean-contaminated surgery (where there is no sign of infection before surgery, but the surgery involves repairing or removing an internal organ such as in appendicitis) or contaminated surgery (open wounds or surgery that involves breaks in sterile technique, for example to undertake cardiac massage, or spillage from the gastrointestinal tract) (NICE 2020).
Following any surgical procedure, tissue oxygenation is required for collagen synthesis and wound repair. Therefore, NICE (2020) recommends maintaining adequate perfusion and oxygen saturation of haemoglobin of more than 95% during surgery and the recovery period.
During surgery, patients are at risk of developing hypothermia from cold operating departments, impaired thermoregulation due to anaesthesia and the use of intravenous fluids. Hypothermia reduces circulation of blood through the skin and may therefore increase the risk of developing an SSI (Tanner et al 2021). The patient’s temperature should be monitored regularly and normothermia should be maintained where this is not contraindicated by the surgical procedure. Nurses should also encourage patients to say if they feel cold and to request additional blankets to ensure normothermia is maintained.
Application of local antibiotics or antiseptics to the surgical wound before closure is only advocated as part of clinical research trials due to the risk of hypersensitive reactions and allergic contact dermatitis (NICE 2020). However, antimicrobial-coated sutures, such as triclosan, are recommended during surgery to reduce the risk of SSIs (WHO 2018, NICE 2020).
Dressings can be used to cover the surgical site, providing protection and preventing contamination until the skin’s continuity has been restored (Dumville et al 2016). WHO (2018) recommends that surgical dressings should remain undisturbed for a minimum of 48 hours once in place, unless there is leakage. If the dressing does require changing, sterile saline should be used for cleaning wounds up to 48 hours after surgery and the dressing should be changed using an aseptic non-touch technique (NICE 2020). After 48 hours, patients may safely shower and tap water can be used to clean the wound if the edges have separated or been surgically opened to drain pus (NICE 2020).
Dressings should be selected on their ability to absorb exudate and prevent bacterial contamination from the external environment. There is increasing research interest in the prophylactic use of negative pressure wound therapy (NPWT) – dressing systems that apply sub-atmospheric pressure to the surface of a wound to promote healing – because it results in reduced oedema and faster tissue healing (Long et al 2022). There is encouraging evidence from a systematic review that NPWT may reduce SSI incidence in wounds healing by primary intention (where the wound edges are closely re-approximated), although there was limited difference in the reported incidence of wound dehiscence using NPWT compared with standard dressings (Norman et al 2022).
The WHO (2018) recommends the use of prophylactic NPWT in adult patients with surgical incisions that are healing by primary intention. However, the benefits of NPWT are not universal and may vary by patient, procedure and wound type. NICE (2022) guidelines have been updated to reflect new evidence that prophylactic NPWT should not be recommended routinely for all patients. Nurses should access tissue viability services for individualised, up-to-date and specialist advice on dressings with the appropriate properties to manage a patient’s wound and prevent SSIs.
Signs and symptoms of SSIs may occur locally at the wound site or systemically. Local signs and symptoms of SSI include increased localised temperature, erythema, pain and swelling of the incision site and purulent drainage from the incision. Spontaneous dehiscence of the wound or the development of a fistula or sinus may also be a local indication of infection. Systemic signs and symptoms of SSI include pyrexia, loss of appetite or raised white cell count (NICE 2020). A comprehensive list of local and systemic signs and symptoms of SSIs is shown in Table 1.
It is essential that an SSI is identified and managed promptly to reduce the effects of the infection and to support healing. SSIs may be diagnosed through the identification of clinical signs and symptoms, the identification of microorganisms from wound swabs, histopathologic samples from deep tissues and blood cultures. Imaging technology such as magnetic resonance imaging or computed tomography may also be used to identify deep incisional infections (Seidelman and Anderson 2021).
SSIs are classified as an incisional infection (superficial or deep) or as an organ and/or space infection (Dumville et al 2016, WHO 2018, UKHSA 2022):
• Superficial incisional infection involves the skin and subcutaneous tissue.
• Deep incisional infection involves the deep soft tissues of the fascia or muscle layers.
• Organ and/or space infection involves the area or part of the anatomy that has been opened or manipulated during the surgery (other than the incision).
Osteomyelitis (bone infection) may also occur due to contamination from a contiguous source (where infection spreads from the surgical site to a nearby bone) or from haematogenous spread (where infection is transported by the blood) (Graan and Balogh 2022).
An understanding of the normal healing process will assist the nurse in early identification of a wound that is not healing as anticipated following surgery. Delayed healing may be due to patient comorbidities, such as inflammatory or autoimmune conditions, medicines, for example corticosteroids, non-steroidal anti-inflammatory medicines and chemotherapeutic medicines, or the presence of infection, including SSI (Gushiken et al 2021).
The nurse should assess the patient’s wound at every dressing change, inspecting the surgical incision and any drain sites for signs and symptoms of infection (Table 1). The assessment and wound care provided should be clearly documented in the patient’s care plan and photographs of the wound can be used to supplement this documentation. Where the nurse suspects an SSI, the wound’s infection parameters, such as increased temperature, erythema and swelling and/or unexpected pain or tenderness, should be closely monitored.
Where an SSI has been identified, targeted antibiotic therapy may be used; however, prescribers should adhere to the principles of antimicrobial stewardship, such as regularly reviewing the need for continued antibiotic use and stopping antibiotics when there is no evidence of infection (Public Health England 2013, NICE 2020).
It is important that nurses take a holistic approach to preventing and managing SSIs. The presence of an SSI can adversely affect the physical, psychological and social well-being of the person and their overall quality of life (Avsar et al 2021). Andersson et al (2010) reported that mental distress, depression, isolation and anxiety are commonly associated with SSIs. Similarly, Tanner et al’s (2013) exploration of patient narratives related to SSIs noted that the odour and exudate associated with infected wounds can cause shame and embarrassment. Consequently, SSIs can make it challenging for patients to interact with other people, which may have a negative effect on their ability to access their social networks and support (Avsar et al 2021).
SSIs also have economic implications for patients, including potential loss of work or reduced productivity due to extended wound treatment and functional decline, and the financial costs associated with wound care, such as dressings, prescriptions and travel to appointments (Andersson et al 2010). However, research on patients’ experiences of SSIs is limited and nurses would benefit from further qualitative exploration to inform best practice.
Before discharge, nurses should provide patients with clear information about caring for their wound, the signs and symptoms of an SSI and who to contact if they have any questions or concerns. Providing an information leaflet on SSIs can assist patients in retaining information and enable them to revisit this at a later point. The use of digital technology such as smartphones has been shown to be effective in relation to assessing wounds, enabling triage and assisting with early recognition and treatment of SSIs (McLean et al 2021).
Nurses have an important role in preventing SSIs and monitoring for signs and symptoms of infection throughout the patient’s surgical journey. Due to their close clinical relationships with patients, nurses are ideally placed to take a person-centred and holistic approach to ongoing assessments or reviews, thereby minimising the risk of developing SSIs and promoting patient satisfaction. An assessment should consider the context in which the patient lives and any psychosocial factors, such as the care setting, the patient’s motivation, occupational status and financial circumstances, and the support available to them. For example, patient education on diet before or following surgery should consider the person’s ability to eat and drink independently, their access to food of nutritional value and their ability to store or prepare food appropriately. For the nurse, using a clear individualised approach can assist in relieving the patient’s anxiety and promoting positive outcomes (NICE 2021).
Prevention and management of SSIs requires a multidisciplinary approach. Preventative interventions should be implemented based on patient risk factors and used to supplement standard infection control precautions, such as appropriate hand hygiene, respiratory hygiene and the use of PPE. Alongside the use of antimicrobials, these measures will assist in reducing the risk of environmental contamination of a patient’s open wound. Where an SSI does occur, surveillance systems such as that provided by the UK’s Health Security Agency (www.gov.uk/guidance/surgical-site-infection-surveillance-service-ssiss) can be used to monitor the frequency and type of infection, patterns of infection and any instances of antibiotic resistance. Such monitoring can assist in the development of an evidence-based approach to care of patients with an SSI.
SSIs can cause significant harm to patients. A holistic nursing approach is required to reduce the risk of patients developing an infection across the preoperative, intraoperative and post-operative phases. Preventive strategies focus on optimising the patient’s condition and minimising the risk of bacterial wound contamination. Nurses have a central role in preventing SSIs through the assessment, monitoring and management of risk factors, as well as supporting the patient to take an active role in their own care.
Developing a clinic to meet patients’ pre-operative needs
This article describes a practice development project at a...
Exudate management in fungating malignant wounds
Fungating wounds are caused by infiltration of the skin by a...
Aspergillus infection control in caring for BMT patients
Many complications can occur following a bone marrow...
Hickman line surveillance in oncology
This article describes the development of a surveillance...
Severe sepsis in A&E
In this article, the author clarifies the definition of...