European Journal of Cardiovascular Medicine

Surgical Site Infections (SSIs) are a major cause of postoperative morbidity and mortality worldwide, particularly following abdominal surgeries. They are among the most common healthcare-associated infections (HAIs), leading to prolonged hospital stays, increased healthcare costs, and higher rates of antimicrobial resistance [1,2]. The Centers for Disease Control and Prevention (CDC) defines an SSI as an infection occurring at or near a surgical incision within 30 days postoperatively (or within one year if an implant is in place), with varying degrees of severity-superficial, deep, or organ/space infections [3].

In India, where healthcare infrastructure and infection control practices vary across institutions, SSIs remain a significant challenge, particularly in emergency abdominal surgeries where preoperative patient optimization is often limited, and wound contamination is more likely [4,5]. Multiple patient-related and procedural risk factors influence SSI incidence, including advanced age, diabetes mellitus, anemia, smoking, obesity, poor nutritional status, and prolonged surgical duration [6-8]. For example, diabetes has been shown to increase SSI risk in emergency abdominal surgery to as high as 33% compared to 12.5% in elective cases [4]. Prolonged operative times (>60 minutes) are also strongly associated with increased SSI risk, especially in contaminated and dirty wounds [8,9].

The emergence of multidrug-resistant (MDR) pathogens such as Escherichia coli and Staphylococcus aureus complicates SSI management, necessitating robust infection control and antibiotic stewardship strategies [10,11]. Elective and emergency surgeries differ significantly in terms of wound classification and risk. Emergency surgeries often involve contaminated or dirty wounds, while elective surgeries allow for better preoperative optimization, antibiotic prophylaxis, and controlled surgical environments [4,12]. Understanding local microbial profiles and resistance patterns is essential for tailoring empirical treatment and implementing effective infection prevention measures.

This study aims to evaluate the incidence, risk factors, and microbial profile of SSIs following abdominal surgeries at a tertiary care hospital in India. By comparing emergency and planned surgeries, this research seeks to identify high-risk groups, analyze microbiological patterns, and recommend targeted infection prevention strategies to improve surgical outcomes.

Study Design and Setting

This observational study was conducted at Naraina Medical College and Research Centre, Kanpur, India, to evaluate the incidence, risk factors, microbial profile, and clinical features of Surgical Site Infections (SSIs) following abdominal surgeries. The study included both emergency and planned (elective) abdominal surgical procedures.

Study Population

Patients aged 18 years and above who underwent abdominal surgeries during the study period and provided written informed consent were enrolled. The patients were divided into two groups:

• Group A (Emergency surgeries)
• Group B (Planned surgeries)

Inclusion Criteria

• Patients aged ≥18 years.
• Undergoing abdominal surgery (elective or emergency).
• Provided informed written consent for participation.

Exclusion Criteria

• Patients with pre-existing surgical site infections.
• Individuals with immunosuppressive conditions such as HIV/AIDS or undergoing chemotherapy.
• Patients unwilling to participate.

Sample Size and Sampling Technique

The sample size was calculated using the formula:

n = \frac{Z^2 \cdot p \cdot (1 - p)}{d^2}

Where:

• p = expected prevalence of SSIs (5.6% or 0.056) [4],
• Z = Z-value for 95% confidence (1.96),
• d = desired precision (5% or 0.05).
  This yielded a minimum required sample size of 82 patients, who were selected using consecutive sampling.

Data Collection Procedure

A structured case report form (CRF) was used to collect preoperative, intraoperative, and postoperative clinical data, including:

• Patient demographics and comorbidities (e.g., diabetes, hypertension, anemia, smoking status).
• Type and duration of surgery.
• Wound classification (clean, clean-contaminated, contaminated, dirty).
• Presence and type of SSI.
• Microbial isolates from wound swabs.
• Clinical signs and symptoms of infection (e.g., fever, discharge, redness, swelling, tachycardia).

Wound swabs from suspected infection sites were sent for microbiological analysis, including organism identification and antibiotic susceptibility testing following standard bacteriological techniques.

Statistical Analysis

Data were entered and analyzed using SPSS software.

• Descriptive statistics (mean, standard deviation, frequency, percentages) were used to summarize demographic and clinical variables.
• Chi-square test and Fisher’s exact test were applied for categorical variables.
• A p-value < 0.05 was considered statistically significant.

In this study, a total of 41 patients underwent emergency surgeries and 41 underwent planned surgeries. Males accounted for 34 (82.93%) in the emergency group and 31 (75.61%) in the planned group, while females made up 7 (17.07%) and 10 (24.39%), respectively. SSIs were more common in emergency surgeries 17/41 (41.46%) than planned surgeries 6/41 (14.63%) (P-value = 0.576). In emergency cases, the highest infection rate was in the 31-45 years group 7/12 (58.33%), while in planned cases, the ≥60 year’s group had the highest rate 3/8 (37.50%). Males had a higher SSI rate in emergency surgeries 14/34 (41.18%), whereas females had a higher rate in planned surgeries 4/10 (40.00%). The difference in SSI incidence between sexes was statistically significant (p = 0.024) [Table 1].

As shown in Table 2, the incidence of SSIs in patients with diabetes was 4 out of 10 (40.00%) in the emergency group (Group A) and 2 out of 12 (16.67%) in the planned group (Group B). In Group A, the incidence of SSIs was 2 out of 13 (15.38%) among patients with hypertension, whereas in Group B, 1 out of 12 patients (8.33%) with hypertension developed SSIs. The incidence of SSIs in anemic patients was 3 out of 10 (30.00%) in Group A, compared to 1 out of 8 (12.50%) in Group B. Additionally, the incidence of SSIs among smokers was 6 out of 24 (25.00%) in Group A and 2 out of 19 (10.53%) in Group B. These findings suggest indicate that diabetes, anemia, and smoking were associated with increased SSI risk, especially in emergency surgeries, emphasizing the need for enhanced perioperative infection control strategies for high-risk patients.

In emergency surgeries, as shown in Table 3, the risk of SSIs was 4 out of 19 (21.05%) in appendicectomies, while in planned surgeries, it was slightly lower at 2 out of 10 (20.00%). Peptic perforation repair had a high SSI rate of 3 out of 5 (60.00%), as these cases were exclusively operated on in emergencies. Intestinal perforation peritonitis repair had the highest SSI risk, accounting for 6 out of 9 (66.67%) of cases. Among other emergency procedures, blunt trauma abdomen (laparotomy) also had a 2 out of 3 (66.67%) SSI rate, and sub-acute intestinal obstruction (SAIO) had a 2 out of 5 (40.00%) SSI rate.

Table 4 presents the distribution of surgical site infections (SSIs) across different wound classes in both emergency and planned surgeries. Within the emergency group, the highest SSI rate was observed in dirty wounds, with 10 infections among 17 patients (58.82%), followed by contaminated wounds with 4 infections among 10 patients (40.00%), and clean-contaminated wounds with 3 infections among 14 patients (21.43%). No SSIs were reported in clean wounds (0 out of 0) in the emergency group. In the planned surgery group, clean-contaminated wounds had the highest infection rate, with 5 SSIs among 16 patients (31.25%), while clean wounds had only 1 infection among 25 patients (4.00%). No infections occurred in contaminated or dirty wounds (0 out of 0) in the planned group. The difference in SSI incidence between the groups across various wound classes was statistically significant (Fisher’s exact test, p = 0.002), indicating that higher wound contamination levels were strongly associated with increased risk of postoperative infections, particularly in emergency surgical procedures.

Table 5 highlights the distribution according to the duration of surgery and the occurrence of surgical site infections (SSIs) in both emergency and planned procedures. The distribution of surgical site infections (SSIs) based on the duration of surgery revealed that longer operative time was associated with a higher incidence of infections in both emergency and planned procedures. In emergency surgeries, 14 out of 32 patients (43.75%) who underwent procedures lasting ≥60 minutes developed SSIs, compared to 3 out of 9 patients (33.33%) whose surgeries lasted <60 minutes. Among the emergency cases with ≥60-minute duration, dirty wounds had the highest SSI rate (7/13; 53.85%), followed by contaminated wounds (4/9; 44.44%) and clean-contaminated wounds (3/10; 30.00%). In surgeries lasting <60 minutes, 3 out of 4 dirty wounds (75.00%) developed SSIs, while no infections were observed in contaminated wounds (0/1), and clean-contaminated wounds (0/4).

In the planned group, 2 of the 28 patients whose surgeries lasted <60 minutes developed SSIs (7.14%). However, among the 13 patients with surgeries ≥60 minutes, 4 developed SSIs (30.76%). These infections occurred primarily in clean-contaminated wounds (3/6; 50.00%) and to a lesser extent in clean wounds (1/7; 14.29%). No contaminated or dirty wounds were present in the planned group. Overall, the data suggest that both prolonged operative time and wound contamination status are major contributors to the increased risk of SSIs, particularly in emergency surgical settings.

Table 6 provides details on the organisms cultured from infected post-operative wounds and the clinical examination findings in both emergency and planned surgery groups. The microbiological profile of surgical site infections (SSIs) revealed notable differences between emergency and planned abdominal surgeries. In the emergency group, Escherichia coli was the most frequently isolated organism, found in 10 out of 17 infected cases (58.82%), followed by Staphylococcus aureus in 4 cases (23.53%), Pseudomonas in 2 cases (11.76%), and Citrobacter in 1 case (5.89%). In contrast, in the planned group, Staphylococcus aureus was the most common pathogen, identified in 3 out of 6 infected cases (50.00%), while Escherichia coli, Pseudomonas, and Citrobacter were each isolated in 1 case (16.67%) each.

Clinical examination findings among patients with SSIs also differed between the two groups. In the emergency group (n=17), the most frequently observed clinical signs were tachycardia in 15 (88.24%), wound discharge in 14 patients (82.35%), and fever in 12 (70.58%). Other notable signs included pain in 8 patients (47.06%), redness or edema in 7 (41.18%), and swelling in 5 (29.41%). In comparison, the planned group (n=6) also showed tachycardia in all cases (100.00%), Discharge and fever each in 5 patients (83.33%), pain and swelling in 4 (66.67%), and redness or edema in 3 (50.00%).

Our study revealed higher SSI rates in emergency surgeries 17 (41.46%) compared to planned surgeries 6 (14.63%) (p = 0.258), consistent with findings by Jatoliya et al. [4] and Kehinde et al. [13]. Younger adults (31–45 years) undergoing emergency surgeries were most affected, aligning with the observations of Razavi et al. [7]. This pattern may reflect the increased urgency, limited preoperative optimization, and higher wound contamination risk in emergency cases.

Diabetes mellitus, anemia, and smoking emerged as prominent risk factors, particularly in emergency cases, corroborating the reports of Shrestha et al. [14] and Lilani et al. [15]. Smoking, in particular, impairs wound healing and immune response, thereby exacerbating infection risk [9]. Additional risk factors, such as obesity and poor nutritional status, have also been implicated in increased SSI rates, as highlighted by Carlsson et al. [16].

Wound classification played a crucial role in SSI incidence, with dirty 10 (58.82%) and contaminated 3 (21.43%) wounds demonstrating higher infection rates in emergency surgeries. These findings are consistent with CDC definitions [2] and Mangram et al.’s guidelines [1]. Notably, no SSIs were observed in contaminated or dirty wounds in planned surgeries, likely reflecting better preoperative preparation and intraoperative management.

Prolonged surgical duration (≥60 minutes) was associated with increased SSI rates in both emergency and planned cases, supporting findings by Blumetti et al. [8] and Kamat et al. [17]. Minimizing operative time remains an important strategy to mitigate infection risk.

Regarding microbiological profiles, Escherichia coli was the predominant pathogen in emergency surgeries 10 (58.82%), while Staphylococcus aureus was more commonly isolated in planned surgeries 3 (50.00%), aligning with observations by Narula et al. [6] and Amrutham et al. [18]. The high culture positivity rate in emergency surgeries 17 (41.46%) suggests a greater bacterial load, emphasizing the need for effective perioperative infection control. The emergence of multidrug-resistant strains reinforces the importance of local surveillance and antimicrobial stewardship [10,11,19].

Clinical signs such as tachycardia, wound discharge, and fever were more frequently observed in emergency surgery patients, consistent with findings by Amrutham et al. [18]. Early recognition and prompt management of these clinical features are crucial for effective SSI control.

Effective SSI prevention requires a multifaceted approach, including preoperative patient optimization, adherence to aseptic techniques, timely administration of prophylactic antibiotics, and meticulous postoperative wound care. The WHO and CDC recommend comprehensive prevention bundles, including preoperative skin preparation, appropriate antibiotic timing, intraoperative protocols, and perioperative care [10,11,20]. Additionally, guidelines from the American College of Surgeons and the Surgical Infection Society emphasize evidence-based strategies for SSI prevention, especially in high-risk surgeries [21]. The WHO’s Safe Surgery Guidelines also underscore the importance of standardized surgical practices to minimize infection risks [22]. Furthermore, Badia et al. [23] highlighted the impact of SSIs on healthcare costs and patient outcomes, reinforcing the need for effective infection prevention strategies.

Overall, our findings highlight the urgent need for targeted infection prevention strategies, particularly in emergency abdominal surgeries, where the risk of SSIs is higher due to patient- and procedure-related factors. Implementing robust infection control measures and antibiotic stewardship programs is essential to improve surgical outcomes and reduce the burden of SSIs.

Limitations: This study has several limitations. First, it was conducted at a single tertiary care center with a relatively small sample size of patients, which may limit the generalizability of the findings to other healthcare settings. Second, the observational design did not allow for control over confounding variables such as variations in surgical technique, surgeon experience, and intraoperative environmental factors, all of which could influence SSI rates. Third, the follow-up period was limited to the inpatient stay and immediate postoperative phase, potentially missing SSIs that developed after discharge. Additionally, microbiological culture sensitivity may have been influenced by prior antibiotic use, possibly underestimating certain pathogens. Despite these limitations, the study provides valuable insights into the risk factors and microbial patterns associated with SSIs in emergency versus planned abdominal surgeries.

This study establishes that SSIs are significantly more common following emergency abdominal surgeries than planned ones, with infection risk amplified by factors such as comorbidities (especially diabetes and anemia), longer operative duration, and contaminated or dirty wound classifications. Emergency procedures for conditions like intestinal or peptic perforations showed the highest susceptibility to SSIs. The predominant organisms isolated were Escherichia coli and Staphylococcus aureus, with varied antibiotic sensitivities that call for updated empirical treatment protocols.

To mitigate the SSI burden, especially in emergencies, it is crucial to enhance preoperative patient optimization, maintain strict aseptic techniques, shorten operative times where feasible, and implement rigorous postoperative wound surveillance. Identifying and monitoring high-risk patients—such as those with diabetes, anemia, and a history of smoking—can help reduce complications. The findings support the need for tailored infection control policies and hospital-wide SSI prevention strategies, particularly focused on emergency surgical settings.

Table1: Distribution of Surgical Site Infections (SSIs) by Age and Sex in Emergency and Planned Surgeries

Table 2: Distribution of Surgical Site Infections (SSIs) Based on Comorbidities and Smoking Status

Table 3: Distribution of SSIs According to the Type of Surgery

Table 4: Distribution of SSIs in Different Classes of Wounds in Emergency vs. Planned Surgeries

Table 5: Distribution of SSIs According to the Duration of Surgery

Table 6: Distribution of Organisms Cultured from Infected Post-Operative Wounds and Clinical Examination Findings in Both Groups

Figure 1: Distribution of Surgical Site Infections (SSIs) by Age in Emergency and Planned Surgeries

Figure 2: Distribution of Surgical Site Infections (SSIs) by Sex in Emergency and Planned Surgeries

Figure 3: Distribution of Surgical Site Infections (SSIs) Based on Comorbidities and Smoking Status

1. Mangram AJ, Horan TC, Pearson ML, Silver LC, Jarvis WR. Guideline for prevention of surgical site infection, 1999. Infect Control Hosp Epidemiol. 1999;20(4):250–78.
2. Horan TC, Gaynes RP, Martone WJ, Jarvis WR, Emori TG. CDC definitions of nosocomial surgical site infections, 1992. Infect Control Hosp Epidemiol. 1992;13(10):606–8.
3. Kirby JP, Mazuski JE. Prevention of surgical site infection. Surg Clin North Am. 2009;89(2):365–viii. doi:10.1016/j.suc.2009.01.001.
4. Jatoliya H, Pipal RK, Pipal DK, et al. Surgical Site Infections in Elective and Emergency Abdominal Surgeries: A Prospective Observational Study. Cureus. 2023;15(10):e48071.
5. Alkaaki A, Al-Radi OO, Khoja A, et al. Surgical site infection following abdominal surgery: a prospective cohort study. Can J Surg. 2019;62(2):111–7.
6. Narula H, Chikara G, Gupta P. A prospective study on bacteriological profile and antibiogram of postoperative wound infections in a tertiary care hospital in Western Rajasthan. J Family Med Prim Care. 2020;9(4):1927–1934.
7. Razavi SM, Ibrahimpoor M, Sabouri Kashani A, Jafarian A. Abdominal surgical site infections: incidence and risk factors at an Iranian teaching hospital. BMC Surg. 2005;5:2.
8. Blumetti J, Luu M, Sarosi G, et al. Surgical site infections after colorectal surgery: do risk factors vary depending on the type of infection considered? Surgery. 2007;142(5):704–11.
9. Dellinger EP. Prevention of hospital-acquired infections. Surg Infect (Larchmt). 2016;17(4):422–426. doi:10.1089/sur.2016.048.
10. Berríos-Torres SI, Umscheid CA, Bratzler DW, et al. Centers for Disease Control and Prevention guideline for the prevention of surgical site infection, 2017. JAMA Surg. 2017;152(8):784–791. doi:10.1001/jamasurg.2017.0904.
11. Allegranzi B, Bischoff P, de Jonge S, et al. New WHO recommendations on preoperative measures for surgical site infection prevention: an evidence-based global perspective. Lancet Infect Dis. 2016;16(12):e276–e287. doi:10.1016/S1473-3099(16)30398-X.
12. Nandi PL, Soundara Rajan S, Mak KC, Chan SC, So YP. Surgical wound infection. Hong Kong Med J. 1999;5(1):82–86.
13. Kehinde SJ, Ojo OA, Oyedepo OO, et al. Surgical site infections in a tertiary hospital: prevalence, risk factors, and microbial profile. Niger J Clin Pract. 2020;23(4):521–527.
14. Shrestha S, Wenju P, Baral R, Karmacharya RM. Incidence and risk factors of surgical site infections in Kathmandu University Hospital, Kavre, Nepal. J Nepal Health Res Counc. 2016;14(33):193–198.
15. Lilani SP, Jangale N, Chowdhary A, Daver GB. Surgical site infection in clean and clean-contaminated cases. Indian J Med Microbiol. 2005;23(4):249–252.
16. Carlsson AK, Lidgren L, Lindberg L. Prophylactic antibiotics against early and late deep infections after total hip replacements. Acta Orthop Scand. 1977;48(4):405–410. doi:10.3109/17453677708992017.
17. Kamat US, Ferreira AM, Savio R, Motghare DD. Antimicrobial prophylaxis to prevent surgical site infections in a tertiary care hospital. Indian J Surg. 2017;79(6):481–486.
18. Amrutham R, Reddy MMB, Pyadala N. A prospective study of surgical site infections and related risk factors in a teaching hospital. Int Surg J. 2017;4(1):237–241. doi:10.18203/2349-2902.isj20164448.
19. Owens CD, Stoessel K. Surgical site infections: epidemiology, microbiology and prevention. J Hosp Infect. 2008;70(Suppl 2):3–10. doi:10.1016/S0195-6701(08)60017-1.
20. Anderson DJ, Podgorny K, Berríos-Torres SI, et al. Strategies to prevent surgical site infections in acute care hospitals: 2014 update. Infect Control Hosp Epidemiol. 2014;35(Suppl 2):S66–88. doi:10.1086/676022.
21. Ban KA, Minei JP, Laronga C, et al. American College of Surgeons and Surgical Infection Society: Surgical Site Infection Guidelines, 2016 Update. J Am Coll Surg. 2017;224(1):59–74. doi:10.1016/j.jamcollsurg.2016.10.029.
22. Allegranzi B, Zayed B, Bischoff P, et al. WHO Guidelines for safe surgery 2009: safe surgery saves lives. Geneva: WHO; 2009.
23. Badia JM, Casey AL, Petrosillo N, Hudson PM, Mitchell SA, Crosby C. Impact of surgical site infection on healthcare costs and patient outcomes: a systematic review in Europe and the United States. Infect Control Hosp Epidemiol. 2017;38(3):313–22. doi:10.1017/ice.2016.269.