Surgical site infections: A narrative review of risk factors, prevention, and emerging innovations

INTRODUCTION

Surgical site infections (SSIs) have been around for many years and continue to be an important element of post-operative care, resulting in a substantial burden of patient morbidity and ultimately healthcare expenditures.^[1,2] SSIs are defined as an infection that occurs at or near a surgical incision within 30 days of an operative procedure, and for an implant, up to one year.^[3] SSIs are among the most common healthcare-associated infections (HAIs) worldwide, accounting for 14–16% of all HAIs in the hospital setting and 38% among surgical patients specifically.^[2] One systematic review with 43 studies across 29 countries summarized a pooled global incidence of 2.5%. However, the incidence in low and middle-income countries (LMICs) is even higher, with rates as high as 11.8% out of 100 surgical procedures in LMICs.^[2] SSI control and awareness have developed greatly over the years. Although doctors use the latest techniques and good hygiene, SSIs can still be difficult, especially where resources are lacking.^[1] SSIs remain a major problem concerning post-operative care throughout India, leading to increased morbidity, prolonged hospital stay, and skyrocketing costs for healthcare.^[4,5] Incidence and prevalence vary widely across different regions and healthcare centers in the country.^[5] In Mumbai, a study lasting four years at a private tertiary-care hospital found that 1.6% of 24,355 surgical patients had SSI after clean and clean-contaminated procedures.^[5,6] The major causative pathogens are Gram-negative Bacilli, predominantly Escherichia coli and Klebsiella spp., including a considerable number of extended-spectrum b-lactamase producers.^[6]

On the other hand, higher rates have been recorded elsewhere in India.^[7] A certain study in a teaching hospital at Ujjain, Madhya Pradesh, clinched a 5% SSI rate among 720 patients, establishing that factors such as disease severity, drain presence, and long duration for surgery have been major risk contributors.^[7] In Trichy, Tamil Nadu, a cross-sectional study brought out the picture of an SSI prevalence rate of 5.6% among 2,076 surgical patients, with abdominal surgery, emergency operation, and diabetes being major risk factors.^[8] Some hospitals have seen even higher numbers. A tertiary care hospital in Mumbai found an 11% SSI rate in 1,196 patients after surgery.^[9] They noticed that being over the age of 55, having diabetes, and needing emergency surgery made it more likely to suffer from SSI.^[9] These differences show we need to make infection control the same everywhere and take specific steps in Indian hospitals to cut down on SSIs.^[4] The World Health Organization stresses the need to follow proven guidelines to prevent SSIs.^[3] These include proper hand cleaning before surgery, using antibiotics, and creating a good setting for operations.^[10] SSIs also lead to longer hospital stays, more patients coming back, and huge costs for health care.^[3] To achieve conceptual clarity on this review, we categorized the risk factors as traditional (i.e., those that have been consistently identified in earlier literature, e.g., diabetes, wound class, and surgery duration), and emerging risk factors include newly identified or emerging determinants such as antimicrobial resistance trends, perioperative glycemic variability, and environmental or technological factors.^[1,2] This focus on the Indian healthcare setting can be explained by the heterogeneity of its healthcare infrastructure, inconsistent infection control measures, and high surgical volume, all of which are indicative of issues common to most LMICs. Therefore, the conclusions made in this setting can be generalized at large to other LMICs.^[2] Comparative incidence of SSIs across global, LMIC, and Indian healthcare settings has been depicted in Figure 1.

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Figure 1:

Comparative incidence of surgical site infections across global, LMIC, and Indian healthcare settings. SSI: Surgical site infections; LMIC: Low and middle-income countries.

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SEARCH METHODOLOGY

We performed a structured search of PubMed, Scopus, Web of Science, and Google Scholar (2000–2024) using combinations of keywords and medical subject headings (MeSH) terms “surgical site infections,” “SSI risk factors,” “post-operative infections,” “antibiotic prophylaxis,” “nosocomial infections,” “infection prevention,” “India,” and “emerging treatment strategies for SSIs” linked with Boolean operators. English-language peer-reviewed original articles, systematic reviews, meta-analyses, clinical guidelines, and government reports that addressed incidence, classification, risk factors, prevention, or treatment of SSIs in LMICs (particularly India) were eligible for inclusion. Non-English articles, editorials, and commentaries without primary data and duplicates were excluded. Titles and abstracts were screened accordingly, followed by a full-text review.

Information, including study aims, design, setting, population, methods, outcomes, and conclusions, was extracted manually into a standardized form. Indian data on SSI rates, causative organisms, and hospital interventions received special emphasis. Findings were synthesized narratively and organized by incidence-prevalence patterns, classifications, clinical presentation, traditional and emerging risk factors, prevention strategies, therapeutic approaches, and implementation challenges; summary tables or figures were created, where helpful. To have equal coverage of the existing and new determinants, the literature included was stratified into two broad categories: (i) Traditional risk factors that have been widely reported in the past (e.g., diabetes, obesity, wound class, and surgery duration) and (ii) emerging risk factors including antimicrobial resistance trends, perioperative glycemic variability, and environmental or technological effects. Such stratification allowed an equal weight of analysis to both categories and prevented bias in either direction of existing or recent evidence. Moreover, possible overlaps of interrelated variables were recognized and well considered with cross-reference to study methods and multivariate analyses published in the literature. Where overlap might have been probable, these factors were not considered separately as variables but were grouped together under integrated risk domains because of their multivariate quality. This methodology provides a comprehensive, specific view of SSIs in healthcare. Structured literature search methodology and study selection criteria have been mentioned in Table 1.

REVIEW

SSIs are infections that occur at or near a surgical incision within 30 days of an operative procedure or within one year if an implant is placed and involves skin, subcutaneous tissues, or deeper tissues such as organs or implanted material.^[11] The Centers for Disease Control and Prevention (CDC) identifies three main categories of SSIs, which include superficial incisional, deep incisional, and organ.^[12] Superficial incisional SSIs involve the skin and subcutaneous tissues in the vicinity of the incision.^[12,13] Deep incisional SSIs involve the deeper soft tissues (e.g., fascia, muscle).^[13] Organ SSIs involve any part of the anatomy that was manipulated during surgery (excluding the incision itself), such as organs or body spaces.^[13] Classification of SSIs according to the CDC has been mentioned in Table 2.

CLASSIFICATION OF SURGICAL WOUNDS AND SSI RISK

Classifying surgical wounds into four separate classes is critical in determining the risk of SSIs and guiding perioperative care.^[13] The CDC, as cited in the National Center for Biotechnology Information, describes wounds classified Class I (Clean) as uninfected operative sites with no inflammation and in which the respiratory, alimentary, genital, or uninfected urinary tracts are not entered.^[14] Class I (Clean) wounds are typically created under sterile conditions, and a primary closure occurs, one that carries the least risk of post-operative infection.^[14] Class II (Clean-Contaminated) wounds occur when controlled exposures are made to the respiratory, alimentary, genital, or urinary tracts without unusual contamination.^[14,15] These sites are not free of bacteria, as cleanliness classification suggests, when surgery is planned, and precautions are taken to minimize infection risk.^[15] Clean-contaminated wounds have a moderately increased risk of SSIs than clean wounds, but are still manageable.^[15]

Class III (Contaminated) wounds include open, fresh, accidental wounds, as well as surgical wounds in which there has been a major break in sterile technique (e.g., alcohol prep wiped off) or significant spillage from the gastrointestinal tract.^[14,16] These wounds have a considerably increased risk of infection, because spillage of bowel without pathogens cannot be determined.^[16] Severe contamination is a Class IV (Dirty/Infected) wound, old traumatic wounds with retained devitalized tissue, clinical infection, or perforated viscera at the time of operation.^[14,16] Dirty wounds are considered widely contaminated. They require aggressive management to prevent or control infection. Wound classification is important because it can help assess infection risk.^[14] The surgical wound classification pyramid gradient showing increasing risk of SSIs has been depicted in Figure 2. Surgical wound classification and risk of SSIs have been briefed in Table 3.

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Figure 2:

Surgical wound classification pyramid showing increasing risk of surgical site infection.

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CLINICAL PRESENTATION AND EARLY RECOGNITION OF SSI

Symptoms of SSIs should be identified as early as possible to maximize intervention and recovery.^[17] Typical clinical signs consist of localized redness and swelling, which are usually palpable within three to seven days of surgery.^[17,18] There may be pain or tenderness at the site of incision; this pain or tenderness indicates inflammation in the surrounding tissue.^[18] Another common symptom of SSI would be the presence of pus in incised or opened tissues.^[19] Pus is usually creamy in appearance, cloudy in color, and has a strong foul odor, all indicative of coupling and are associated with bacteria.^[19] Systemic signs such as fever or chills may also occur as SSIs sometimes, at least deeper SSIs, will introduce organisms to your blood, and the potential for circulation of the organism and/or sepsis.^[20,21]

Aside from the aforementioned initial symptoms, some very important clinical signs of SSIs are more pain at the incision than expected postoperatively which can even indicate an underlying abscess; localized wound dehiscence (partial or complete opening of the wound) due to the wound infection damaging the tissue; delayed healing, which is identified with continued slough, necrosis, or no granulation; warmth localized to the incision area (indicating that the inflammatory process is continuing); and in some instances, a malodorous discharge, often showing signs of infection by anaerobic organisms.^[20,22] In the case of severe or organ/space SSIs, you may see additional clinical signs such as abdominal pain (in the case of post-intra-abdominal surgeries), shortness of breath (in the case of thoracic SSIs), or altered mental state (in the case of the elderly or immunocompromised).^[23]

MULTIMODAL STRATEGIES FOR THE PREVENTION OF SSIS

Making sure SSIs do not occur is necessary to ensure better recovery of the patient and for healthcare costs to decline.^[36] The main strategies to prevent SSIs are following surgical aseptic guidelines, using antibiotics early on, and ensuring the patient improves their blood glucose levels and stops smoking.^[36] The timing of prophylaxis is particularly important; administering prophylactic antibiotics within one hour of incision is associated with reduced risk of SSIs since the concentration of prophylactic antibiotics in tissue is highest at the time of incision.^[37]

In addition, restoring normothermia and optimizing oxygenation during the perioperative period improves the immune response against infections, respectively.^[38] Implementation of a standardization surgical bundle with a variety of interventions also demonstrated consistent effectiveness in decreasing SSIs.^[10,39] Preoperative skin cleaning with betadine, chlorhexidine-alcohol-containing agent spirit over the incision site, wearing suitable protective gear, and limiting visitors in the operation room are all part of surgical bundles.^[38] Managing wounds with the best methods and identifying them early in the perioperative phase, along with avoiding unnecessary subcutaneous sutures and less frequency dressing for clean wounds, can further reduce SSIs.^[38] Keeping the air-exposed clean wound with decreased moisture also decreases the risks of bacterial growth from occlusive or semi-occlusive dressings, which helps to reduce the risk of SSIs related to the dressing.^[38,39] It also allows the wound to dry and allows the clinician to monitor the wound.^[38] Early removal of the drain is also an important aspect for the prevention of SSIs.^[39] In summary, a team approach is demanded, since surgical, anesthesia, nursing, and infection experts are needed to prevent SSIs.^[10] The multimodal surgical bundle for SSI prevention across perioperative phases has been described in Figure 3.

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Figure 3:

Multimodal surgical bundle for SSI prevention across perioperative phases. SSIs: Surgical site infections.

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TREATMENT STRATEGIES IN SSI MANAGEMENT

Treatment for SSI depends on how much the infection is spread under or on the surface of the skin.^[40] Damage from a superficial infection can be resolved with regular irrigation, a suitable dressing, and paying close attention to the wound.^[40,41] If an abscess develops, incision and drainage are important, and follow that with a proper dressing and rewound care.^[41] Perhaps for deeper or more complex infections, surgical debridement is key to removing dead or necrotic tissue and to cleaning bacteria from the affected tissue to ensure healing occurs.^[42]

Systemic antibiotic therapy is also an important strategy for the management of SSI.^[43] Empirical antibiotic therapy should address the most likely pathogens and local resistance patterns.^[43] Following culturing and sensitivity testing, specific effective therapy should be instigated, including multi-drug resistant bacteria.^[43] In the face of a mounting “Antibiotic Resistance Crisis,” antibiotic selection must be made judiciously, while optimizing treatment regimens to limit the emergence of resistant strains and ensure maximal patient efficacy.^[43,44] In complicated patients involving multi-drug resistant organisms, it is suggested that physicians consult with an infectious disease specialist to assist with complex antimicrobials.^[43,44] Using adjunctive therapies such as negative pressure wound therapy, advances the healing process by increasing granulation tissue and reducing fluid accumulation under the skin.^[45] In addition, among diabetic patients, the same can be said regarding optimal glycemic control, nutritional support, and smoking cessation; these adjuncts can support the comprehensive plan of care and improve outcomes.^[41]

BARRIERS AND PROGRESS IN SSI GUIDELINE IMPLEMENTATION IN INDIA

Even with good prevention guidelines, India faces many obstacles while applying them effectively, mainly in areas with few resources.^[50] Many healthcare facilities lack enough sterile instruments, are crowded, and receive their basic infection control supplies on an inconsistent basis.^[50] Limited training and staffing shortages affect the ability to be consistent with the suggested guidelines.^[50,51] The inappropriate or excessive use of antibiotics, together with a lack of microbiological support, means resistance to antimicrobials increased, which complicates SSI management.^[51,52] Cultural differences, which include sporadic compliance with hand hygiene practices and a lack of institutional monitoring mechanisms, are further barriers.^[53] The systemic and structural issues mean that the guidelines need to be pragmatically altered to be usable and generally use cost-effective, scalable interventions that can be implemented reliably, in variable settings, relevant to Indian healthcare facilities.^[3,53]

Despite challenges, India has achieved major progress in areas related to tackling SSIs.^[53] In the National Health Mission, programs concentrate on keeping watch, skill-building, and implementing steps to avoid SSIs in districts and specialist hospitals.^[54] India’s major hygiene and sanitation campaign, the Swachh Bharat Abhiyan, has helped improve healthcare buildings and informed people about hygiene.^[55] Numerous Indian tertiary care hospitals have successfully implemented multimodal bundles promoting infection control as described above.^[6,7,55] These bundles often include intraoperative skin antisepsis, compliance with antibiotic prophylaxis, and meticulous adherence to surgical asepsis protocol, which also includes the use of intra-operative wash and irrigation of the wound before its closure.^[10,44] These programs demonstrate the power of the coordinated efforts of government leadership with engagement from healthcare providers and measure success by addressing chronic surveillance page remains a long-lasting outcome for SSI in India.^[52,56]

CONCLUSIONS

SSIs are still a frequent problem in clinical settings, causing high healthcare costs and additional problems for those undergoing surgery. Using prevention protocols backed by research is a key, but surgical practice can be greatly improved when new technology is used and professionals from various specialties team up. In general, the recommendations stress early recognition, careful antimicrobial use, and treating each patient individually. Issues with implementation, training, and infrastructure are singled out in India due to its limited resources. Research should keep moving forward, and surgeons should collaborate globally to lessen the negative effects of SSIs and advance surgical treatment all over the world.