European Journal of Cardiovascular Medicine

Surgical site infection (SSI) is an infection involving an operative incision or an organ or anatomical space accessed during surgery. Standard definitions distinguish superficial incisional infection, deep incisional infection, and organ/space infection, allowing surveillance to reflect the anatomical extent of disease.[1] These categories also prevent clinically different complications from being combined without adequate explanation. Reliable classification requires clinical assessment alongside relevant microbiological, operative, or imaging findings. Culture results support characterization of infection but do not substitute for a consistent case definition. Established prevention guidance therefore places surveillance within a broader programme of perioperative infection control.[2]

Major abdominal surgery presents a diverse infection risk because procedures involve different organs, degrees of microbial exposure, and underlying diseases. Elective operations undertaken after preparation differ substantially from emergency procedures performed in the presence of obstruction, perforation, or existing infection. International prospective evidence demonstrates that SSI occurrence varies across healthcare settings and levels of intraoperative contamination.[3] Consequently, an overall institutional infection proportion should be interpreted together with operative case mix and wound classification. Local reporting can identify where infections cluster, while comparisons between hospitals require compatible definitions, surveillance periods, and ascertainment procedures.

Patient characteristics contribute additional variation. A systematic review identified an association between diabetes mellitus and SSI across several surgical specialties.[4] Preoperative hypoalbuminaemia has also been associated with infection following gastrointestinal procedures, although albumin reflects inflammation and disease severity as well as nutritional status.[5] Age, anaemia, obesity, and smoking deserve evaluation within the clinical context rather than automatic designation as independent predictors. Operative duration is another relevant exposure; a systematic review found increasing infection risk with longer procedures.[6] These relationships can overlap because complex operations often involve greater contamination, longer operating times, and patients with more severe illness.

Infection prevention depends on coordinated measures before, during, and after surgery. Hospital guidance emphasizes appropriate antimicrobial prophylaxis, aseptic practice, patient preparation, and systematic review of outcomes.[7] The Centers for Disease Control and Prevention guideline additionally supports perioperative practices directed at reducing avoidable infection.[8] Microbiological surveillance complements these measures by documenting recovered organisms. However, organism frequencies alone cannot determine antibiotic effectiveness or local resistance patterns. Interpretation requires the number of specimens, culture-positive cases, isolates, and any polymicrobial infections to be reported with clear denominators.

The objectives of this study were to estimate SSI occurrence following major abdominal surgery at Konaseema Institute of Medical Sciences and Research Foundation, Amalapuram, Andhra Pradesh, India; describe the anatomical categories and microbiological profile of infection; and examine its distribution across demographic, clinical, and operative factors. This observational assessment covers August 2023 to January 2024 and a cohort of 100 patients.

Study design and setting

The specified design was a prospective observational study at Konaseema Institute of Medical Sciences and Research Foundation, Amalapuram, Andhra Pradesh, India, during August 2023 to January 2024. This study has 100 patients.

Participants and study size

The described cohort comprised patients undergoing major abdominal procedures, including elective and emergency operations. Principal operative categories were small-bowel, colorectal, gastric or duodenal, hepatobiliary or pancreatic, and other abdominal surgery. The available sample comprised 100 patients.

Clinical and operative variables

Variables available in the summary were age, sex, diabetes, hypertension, preoperative anaemia, hypoalbuminaemia, obesity, and current smoking. Obesity was categorized as body mass index ≥30 kg/m². Operative variables included urgency, principal procedure category, wound classification, duration, and antibiotic prophylaxis timing. Duration was grouped at 120 minutes. Prophylaxis categories require the actual drug-specific timing interval, informed by established guidance.[9]

Outcome definition and follow-up

The principal outcome was the proportion developing SSI during postoperative surveillance. Infections were grouped as superficial incisional, deep incisional, or organ/space, with each affected patient assigned once to the deepest category.[1,2] The calculation 20/100 represents cumulative incidence only when the denominator has adequate surveillance over the specified interval.

Microbiological assessment

The study described specimens from 20 SSI cases, including 18 positive cultures and two without growth. Organism percentages used 18 recovered isolates as the denominator.

Statistical analysis and reporting

Continuous and categorical variables were summarized using mean ± standard deviation and number with percentage, respectively. Exposure-specific SSI proportions used the number of patients in each category as denominator. Recruitment and ascertainment procedures require documentation to address bias and complete STROBE reporting.[10]

Ethical considerations

Necessary Permissions were obtained before starting the study.

Baseline demographic and clinical characteristics

The cohort comprised 100 patients with a mean age of 49.6 ± 15.2 years. Men constituted 62.0%, and the largest age category was 46–60 years (35.0%). Diabetes, preoperative anaemia, and hypoalbuminaemia were recorded in 30%, 35%, and 25%, respectively (Table 1).

Table 1. Baseline demographic and clinical characteristics (N = 100)

SD: standard deviation; BMI: body mass index.

Operative characteristics

Sixty patients underwent elective surgery and 40 underwent emergency procedures. Small-bowel and colorectal operations represented 28% and 25% of cases. Clean-contaminated wounds accounted for 55%. Forty operations exceeded 120 minutes, and prophylaxis was outside the specified interval in 20 cases (Table 2).

Table 2. Operative characteristics (N = 100)

SSI occurrence and classification

SSI was recorded in 20 patients, corresponding to 20.0% of the cohort. This represents cumulative incidence only if adequate postoperative surveillance is confirmed for all 100 patients. Superficial incisional infection affected 12 patients; deep incisional and organ/space infections affected five and three, respectively (Table 3).

Table 3. SSI occurrence and anatomical classification

Each affected patient was classified once according to the deepest infection category.

Microbiological profile

Of 20 specimens from SSI cases, 18 yielded bacterial growth (90.0%). Escherichia coli accounted for six of the 18 isolates (33.3%). Klebsiella pneumoniae and Staphylococcus aureus each accounted for four isolates (22.2%). Gram-negative and Gram-positive organisms represented 12 (66.7%) and six (33.3%) isolates, respectively (Table 4).

Table 4. Culture results and recovered organisms

Organism percentages assume one recovered isolate per culture-positive patient; this requires confirmation. Rounded organism percentages total 99.9%.

SSI distribution according to potential risk factors

SSI proportions were higher with diabetes (40.0% versus 11.4%), anaemia (34.3% versus 12.3%), and hypoalbuminaemia (40.0% versus 13.3%). Emergency surgery had a higher proportion than elective surgery (35.0% versus 10.0%). Contaminated or dirty/infected wounds had a proportion of 40.0%, compared with 9.2% for clean or clean-contaminated wounds. Exposure-specific findings are presented in Table 5.

Table 5. SSI occurrence according to potential risk factors (N = 100)

Percentages use the total within each exposure category. Comparisons are descriptive; statistical significance and independent prediction were not established.

The study described SSI in 20 of 100 patients, with superficial incisional infections constituting 60.0% of affected cases. This numerical pattern requires validation against patient records and the actual surveillance window. For context, Huda and colleagues reported SSI in 16 of 112 patients undergoing elective laparotomy, corresponding to 14.29%.[11] Their retrospective elective cohort differs from the present description, which includes 40% emergency procedures. International prospective evidence likewise demonstrates substantial variation by setting and intraoperative contamination.[3] Differences in operative mix and outcome ascertainment therefore limit direct comparisons of crude infection proportions.

Eighteen specimens yielded growth, and Gram-negative organisms accounted for two-thirds of the 18 isolates. Escherichia coli was the leading organism, followed by Klebsiella pneumoniae and Staphylococcus aureus. Huda and colleagues also identified E. coli as the predominant isolate.[11] In contrast, Ratnesh and colleagues reported S. aureus as the most frequently recovered bacterium in an Indian abdominal SSI series.[12] Such differences support institution-specific microbiological surveillance. The current counts do not establish resistance patterns, and no antimicrobial recommendation can be derived from species frequencies alone. Specimen quality, previous antibiotic exposure, and the detection of mixed infections also influence culture interpretation.

SSI proportions were higher among patients with diabetes, hypoalbuminaemia, and anaemia. The diabetes comparison, 40.0% versus 11.4%, is directionally consistent with the association identified by Martin and colleagues.[4] Similarly, Hennessey and colleagues linked preoperative hypoalbuminaemia with SSI after gastrointestinal surgery.[5] These published findings provide context rather than validation of the example values. Albumin should not be interpreted as a standalone nutritional diagnosis. Current smokers also had a higher descriptive infection proportion, 33.3% versus 15.8%, consistent with published evidence linking smoking to impaired surgical healing and infection.[13] Overlap between exposures remains unresolved.

Emergency procedures and contaminated or dirty/infected wounds had higher SSI proportions than their respective comparison categories. This pattern agrees with the importance of contamination in international gastrointestinal surveillance.[3] Operations exceeding 120 minutes also showed more infections, consistent with the literature on prolonged operative duration.[6] Nevertheless, urgency, contamination, duration, and physiological severity are interrelated. The present category counts cannot determine whether any factor independently predicts infection. With only 20 events, an extensively parameterized multivariable model would require particular caution.

Prophylaxis outside the specified timing interval was accompanied by a 45.0% SSI proportion, compared with 13.8% within the interval. A systematic review by de Jonge and colleagues supports careful attention to prophylaxis timing.[14] Interpretation here depends on confirming the antibiotic, administration time, incision time, and treatment-versus-prophylaxis distinction. The draft supports further assessment of perioperative processes using verified records. It does not demonstrate that changing a single practice would reduce infection, nor establish statistically significant or causal relationships.

Limitations

This single-centre description includes 100 patients and only 20 infections, restricting precision and adjusted analysis. Susceptibility findings and postoperative outcome measures were unavailable. Descriptive exposure comparisons remain vulnerable to confounding, and the reported organism distribution does not capture unconfirmed polymicrobial, anaerobic, or fungal infections.

The study describe surgical site infection in 20 of 100 patients undergoing major abdominal surgery. Superficial incisional infections predominated, and Escherichia coli was the most frequent recovered organism. Higher infection proportions accompanied diabetes, hypoalbuminaemia, emergency procedures, contaminated or dirty/infected wounds, longer operations, and prophylaxis outside the specified interval.

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