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Year : 2019  |  Volume : 37  |  Issue : 3  |  Page : 318--325

Protocol for developing a surveillance system for surgical site infections

Purva Mathur1, Samarth Mittal2, Vivek Trikha2, Ayush Lohiya1, Surbhi Khurana1, Sonal Katyal1, Nidhi Bhardwaj1, Sushma Sagar3, Subodh Kumar3, Rajesh Malhotra2, Kamini Walia4,  
1 Department of Laboratory Medicine, Jai Prakash Narayan Apex Trauma Center, All India Institute of Medical Sciences, New Delhi, India
2 Department of Orthopedics, Jai Prakash Narayan Apex Trauma Center, All India Institute of Medical Sciences, New Delhi, India
3 Division of Trauma Surgery, Jai Prakash Narayan Apex Trauma Center, All India Institute of Medical Sciences, New Delhi, India
4 Epidemiology and Communicable Diseases, Indian Council of Medical Research, New Delhi, India

Correspondence Address:
Dr. Purva Mathur
Department of Laboratory Medicine, Jai Prakash Narayan Apex Trauma Centre, All India Institute of Medical Sciences, New Delhi - 110 029


Purpose: Healthcare-associated infections (HCAIs/ HAIs) are the most common adverse occurrences during health care delivery. Across the globe, millions of patients are affected by HAIs annually, with a higher burden and impact in developing nations. a major lacuna in planning preventing protocols is the absence of National Surveillance Systems in most low-middle income countries, which also prevents allocation of resources to the high-priority areas. Among all the HAIs, there is a huge global burden of SSIs, in terms of morbidity, prolonged hospital stays, increased antimicrobial treatment as well as attributable mortality. Method: This manuscript details the process of establishment of an SSI surveillance protocol at a level-1 trauma centre in North India. Result and Conclusion: Surveillance is an essential tool to reduce this burden. It is also an important primary step in recognizing problems and priorities, and it plays a crucial role in identifying risk factors for SSI and to be able to target modifiable risk factors. Therefore, it is imperative to establish reliable systems for surveillance of HAIs, to regularly estimate the actual burden of HAIs, and to use these data for developing indigenous preventive measures, tailored to the country's priorities.

How to cite this article:
Mathur P, Mittal S, Trikha V, Lohiya A, Khurana S, Katyal S, Bhardwaj N, Sagar S, Kumar S, Malhotra R, Walia K. Protocol for developing a surveillance system for surgical site infections.Indian J Med Microbiol 2019;37:318-325

How to cite this URL:
Mathur P, Mittal S, Trikha V, Lohiya A, Khurana S, Katyal S, Bhardwaj N, Sagar S, Kumar S, Malhotra R, Walia K. Protocol for developing a surveillance system for surgical site infections. Indian J Med Microbiol [serial online] 2019 [cited 2020 Apr 7 ];37:318-325
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Full Text


Healthcare-associated infections (HCAIs/HAIs) are the most frequent adverse events during health-care delivery. Millions of patients are affected by HAIs every year worldwide; the burden and impact of these infections being greater in low- and middle-income countries (LMICs). Hospital-wide prevalence of HAI varies from 5.7% to 19.1%, with a pooled prevalence of 10.1%. Among the HAIs, surgical site infections (SSIs) are one of the most common, morbid and costly to treat. Worldwide, approximately 187–281 million surgical procedures are performed each year. SSIs are one of the undesirable and serious outcomes of surgeries; despite the high burden, most SSIs are preventable.[1],[2],[3],[4],[5],[6],[7],[8]

The global burden of SSIs is huge, in terms of morbidity, repeat surgeries, prolonged hospitalisation, increased length of antimicrobial treatment and attributable mortality (0.4%–0.8% of SSIs resulting in death). Large-scale studies done in the developed countries as part of national surveillance systems or networks or multi-hospital surveys have reported SSI rates varying from 0.9% to 17.8%, depending primarily on the type of surgeries. A WHO survey found that in LMICs, the incidence of SSI ranged from 1.2 to 23.6/100 surgical procedures. This contrasted with rates between 1.2% and 5.2% in high-income countries. [Table 1] gives a brief overview of the SSI rates in developed nations.[4],[9],[10],[11],[12],[13],[14],[15]{Table 1}

 Burden of Surgical Site Infections in Low- and Middle-Income Countries

The burden of SSIs in these countries is much higher than the developed countries. In the 2011 WHO report on the global burden of HAI from LMICs, SSI was the most frequent HAIs reported hospital-wide, with the level of risk being much higher than in developed countries. In this report, the pooled SSI incidence in LMICs and developed countries were, respectively, 11.8 and 5.6/100 surgical procedures. The rates of SSIs have ranged from 2.1 in the Republic of Korea to 2.5%–15.4% in Uruguay, and 1.9%–3.1% in Chile. The overall prevalence of SSI in Africa/Middle East, Latin America, Asia and China was reported to be 10%, 7%, 4% and 4%, respectively. In a review published in 2019 by Couto et al., the overall prevalence of SSI in developing countries in elective clean and clean-contaminated surgeries was estimated to be 6%, increasing to 15% when studies only focusing on post-discharge surveillance were included.[4],[10],[11],[12],[13],[14],[15],[16]

 Surveillance for Surgical Site Infections

In most countries, the burden of HAIs is grossly underestimated for want of proper surveillance and reporting systems. Estimation of the national burden of HAIs is a prerequisite for planning infection control policies. Robust evidence emphasises the fact that HAI can be prevented, and the burden is reduced by as much as 50%.[17],[18],[19],[20]

Surveillance is defined as “the ongoing, systematic collection, analysis and interpretation of health data essential to the planning, implementation and evaluation of public health practice, closely integrated with the timely dissemination of these data to those who need to know.” Surveillance of SSI is part of the WHO safe surgery guidelines. Many countries have introduced mandatory surveillance of SSI, such as the UK and certain states in the USA, whereas other countries have voluntary-based surveillance, such as France, Germany and Switzerland.[21],[22],[23],[24],[25],[26],[27],[28],[29],[30],[31],[32],[33],[34],[35],[36]

There is a lack of national surveillance systems in most LMIC, which is a major lacuna in planning preventing protocols and allocating resources to the highpriority areas. Therefore, there is an urgent need:

To establish reliable systems for HAI surveillanceTo gather data on the actual burden of HAIs regularlyTo use this data for developing indigenous preventive measures, tailored to the country's priorities.

Evaluation of the key determinants of SSIs (or risk factors) is also an essential step to identify strategies and measures for improvement.

Surveillance of SSIs is very different from other HAIs such as ventilator-associated pneumonia (VAP), central line-associated bloodstream infections (CLABSIs) and catheter-associated urinary tract infections (CAUTIs). The primary difference being that surveillance for VAP, CLABSI and CAUTI are truncated at the time of discharge from the unit/hospital. In contrast, most SSIs develop after the patient is discharged from the hospital, considering the ever-shortening in-hospital stay after surgeries. Some SSIs may develop as long as 3 months or even a year after the surgery. SSI surveillance, therefore, requires a very prolonged follow-up, a lot more engagement by the patients and health-care workers, and therefore, not feasible in many LMICs.[17],[18],[19],[37],[38]

Surveillance is an essential tool to reduce its burden. It is also an important first step in identifying problems and priorities; and it plays an important role in recognising risk factors for SSI thus, helping to target modifiable risk factors.

Carefully obtained surveillance data can identify needed infection prevention and control (IPC) interventions and areas of opportunity for improvements in care. The surveillance data can also help assess the quality of infection prevention efforts. Both process measures (for example, the implementation of preventive measures) and outcome measures (SSI rates) should be measured through surveillance so that IPC measures can be implemented, and performance improved. The application of standardised definitions is one of the minimum requirements for data comparisons at local, national and international levels. The use of standardised definitions is crucial to the reliability of SSI surveillance for the following reasons:

It allows establishing that the infection was acquired during the hospital stayTo ensure that it is a true infection and not colonisationAllows for inter-hospital comparisons and benchmarking.

The National Healthcare Safety Network (NHSN) provides the most reliable and updated definitions.[1],[39],[40] At the All India Institute of Medical Sciences, New Delhi, we have initiated a multi-centric study, supported by ICMR, where 90-day post-discharge surveillance is being conducted to ascertain the actual prevalence of SSI in a select group of surgeries. This manuscript describes the process of the establishment of an SSI surveillance protocol.

Objectives of a surveillance program

Collection of data on SSI rates to ascertain the magnitude of the problemAnalysis of the data to identify and investigate trendsAscertain the most common pathogens and their susceptibility patternsIdentify the risk factors in the Indian set-upInterpretation of analysed data at regular intervals to provide feedbackData-driven improvement actionsEvaluation of preventive interventionsThe following are the essential prerequisites for developing a surveillance system for SSIs[1],[41],[42],[43]An standard operating procedure (SOP) with objectives, methodology and all elements of the surveillance processAdequate human resources for surveillance (infection control nurses and epidemiologists)Training of all surveillance staff (induction and at regular intervals)Consistent application of definitions and common methodologyIT/Informatic services (to design an interpret reports)Data quality/evaluation methodsDevelopment of a feedback mechanismUse surveillance findings in developing/implementing preventive activitiesEach hospital to use its data for internal benchmarking and setting targets.

The SSI surveillance programme should measure both infection rates and compliance rates with surgical infection prevention processes.

 Process and Outcome Measures

SSI surveillance should include measures of processes to indicate whether caregivers are adhering to best practices and established policies as well as the outcomes of care during the pre-operative, intra-operative and post-operative phases.

Process measures

In the pre-operative phase, hand hygiene, accurate assessment of patient status and risk factors, and initiating specific procedures such as maintaining normothermia, are some of the IPC processes. In the intra-operative stage, IPC processes include skin antisepsis, maintaining normothermia and glucose monitoring. Postoperatively, aseptic wound care is a primary prevention process.[44],[45],[46],[47],[48],[49]

Calculation of compliance

All calculations can be performed by using the formula of:

The number of events (numerator) divided by the number of persons at risk or number of expected processes.

Outcome measures

Monitoring/surveillance for surgical site infection

For surveillance purposes, SSIs are divided into categories involving only skin and subcutaneous tissue (superficial incisional SSIs), those involving deeper soft tissues of the incision (deep incisional SSIs), and those involving any part of the deep anatomy (organ space SSIs), such as a joint space. The definitions for SSIs have been adopted from the Centres for Disease Control and Prevention NHSN system.[50],[51],[52] [Table 2] details the classification of SSI.{Table 2}

We have developed a website for SSI surveillance, where the SOP is available. Definitions of SSI surveillance, wound classification and the details of surveillance methodology can be accessed at [Figure 1] shows a screenshot of the home page of the website.{Figure 1}

Case finding

This requires active, patient-based, prospective surveillance. Both in-hospital and post-discharge surveillance methods should be used to detect SSIs. Review methods may include one or more of the following:[50],[51],[52]

Direct inspection of the woundMedical records/surgical/OT notes/physician's notes/admission, readmission, ED notesLaboratory/X-ray, other diagnostic test reportsInformation from the patients and familiesSurveys by mail or telephone.

Role of the Hospital Infection Control Nurses (HICNs) (HICNs)/infection preventionists/epidemiologist/information technology departments (if available)

To lead the development of the SSI surveillance planTo perform the surveillance using established, approved, and consistent surveillance criteria or definitionsAnalyse and present the data to all stakeholders.

Data collection

Collect SSI (numerator) and operative procedure category (denominator) data on all procedures included in the selected procedure categories for at least 1 month. The numerator and denominator data forms are available on the website The surgical procedure must meet the definition of an operative procedure to be included in the surveillance. All procedures should be followed for superficial, deep and organ/space SSIs. All patients undergoing the defined surgeries (for which a hospital intends to undertake SSI surveillance) need to be monitored for SSI. SSI form should be completed for each SSI. The SSI form includes patient demographic information and information about the operative procedure, including the date and type of procedure. Information about the SSI includes the date of SSI, specific criteria met for identifying the SSI when/how the SSI was detected, whether the patient developed a secondary bloodstream infection, whether the patient died, the organism(s) identified and the organisms' antimicrobial susceptibilities.[50],[51],[52]

 Calculation of Surgical Site Infection Rates

The most common outcome indicator is the SSI rate. For any given period, denominator data represent the total number of procedures within each category. Numerator data will be the number of SSIs in that same period. SSI rates per 100 operative procedures are calculated by dividing the number of SSIs by the number of specific operative procedures and multiplying the results by 100. SSIs should be included in the numerator of a rate based on the date of procedure, not the date of the event.[50],[51],[52] [Figure 2] and [Figure 3] show the SSI surveillance case report form and denominator form, respectively. The forms can be accessed at the website{Figure 2}{Figure 3}

Additional terms

Date of event (DOE): For an SSI, the DOE is the date when the first element used to meet the SSI infection criterion occurs for the first time during the SSI surveillance period. The date of the event must fall within the SSI surveillance period to meet SSI criteria. The type of SSI (superficial incisional, deep incisional or organ/space) reported should reflect the deepest tissue layer involved in the infection during the surveillance period. The date of the event should be the date that the patient met the criteria for the deepest level of infectionDuration of operative procedure: The interval in hours and minutes between the procedure/surgery start time (PST), and the procedure/surgery finish (PF) time, as defined by the Association of Anaesthesia Clinical Directors

PST: Time when the procedure is begun (e.g., incision for a surgical procedure)PF: Time, when all instrument and sponge counts are completed and verified as correct, all post-operative radiologic studies to be done in the Operating room (OR), are completed, all dressings and drains are secured, and the physicians/surgeons have completed all procedure-related activities on the patient

Emergency operative procedure: A procedure that is documented as per the hospital's protocol to be an emergency or urgent procedureInpatient operative procedure: An operative procedure performed on a patient whose date of admission to the Healthcare facility (HCF), and the date of discharge are different calendar daysOutpatient operative procedure: An operative procedure performed on a patient whose date of admission to the HCF, and date of discharge are the same calendar dayNon-primary Closure: Closure of the surgical wound in a way which leaves the skin level completely open following the surgery. Closure of any portion of the skin represents primary closure. For surgeries with non-primary closure, the deep tissue layers may be closed by some means (with the skin level left open), or the deep and superficial layers may both be left completely open. Wounds with non-primary closure may or may not be described as 'packed' with gauze or other material, and may or may not be covered with plastic, 'wound vacs', or other synthetic devices or materialsPrimary closure: Closure of the skin level during the original surgery, regardless of the presence of wires, wicks, drains or other devices or objects extruding through the incision. This category includes surgeries where the skin is closed by some means.

If a procedure has multiple incision/laparoscopic trocar sites and any of the incisions are closed primarily then the procedure technique is recorded as primary closed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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