The investigators' hypothesis is that placement of CollatampG in the subcutaneous layer of contaminated abdominal wounds is effective prophylaxis for superficial surgical site infection (SSI). CollatampG is composed of highly purified type 1 collagen obtained from bovine tendon, which acts as a vehicle for the aminoglycoside antibiotic, gentamicin. This implant provides a high concentration of local gentamicin at the surgical wound to decrease the local microorganism load. It has been shown that if a surgical site is contaminated with > 10 to the power of 5 microorganisms per gram of tissue, the risk of infection is markedly increased. When a gastrointestinal organ is the source of pathogens, gram-negative bacilli (e.g., E. coli) are typical isolates, which are susceptible to gentamicin. Therefore, a high local concentration of gentamicin at the contaminated surgical wound provided by the CollatampG implant may prevent the local bacterial load from reaching levels high enough to cause a clinical infection.

Aims: To decrease the incidence of superficial surgical site infection (SSI) using a collagen -gentamicin implant (CollatampG) for patients who undergo major abdominal surgery with contaminated surgical wounds.

Hypotheses: Patients undergoing abdominal surgery with wounds classified as contaminated or dirty are at a high risk of SSI. Wounds are classified as contaminated when an operation is performed through an infected area (e.g abscess, perforated viscus or traumatic wound) that has been exposed for over 4 hours. Risk of infection in these wounds has been shown to be as high as 45 %.

Our hypothesis is that placement of CollatampG in the subcutaneous layer of contaminated abdominal wounds is effective prophylaxis for superficial SSI. CollatampG is composed of highly purified type 1 collagen obtained from bovine tendon, which acts as a vehicle for the aminoglycoside antibiotic, gentamicin. This implant provides a high concentration of local gentamicin at the surgical wound to decrease the local microorganism load. It has been shown that if a surgical site is contaminated with >10 to the power of 5 microorganisms per gram of tissue, the risk of infection is markedly increased. When a gastrointestinal organ is the source of pathogens, gram-negative bacilli (e.g., E. coli) are typical isolates, which are susceptible to gentamicin. Therefore, a high local concentration of gentamicin at the contaminated surgical wound provided by the CollatampG implant may prevent the local bacterial load from reaching levels high enough to cause a clinical infection.

Inclusion Criteria:

• Patients having a preoperative diagnosis of perforated viscus, perforated gastrointestinal tumour, or intraabdominal abscess (based on clinical and radiological findings), requiring abdominal surgery.
• Patient with prolonged surgery (operative time charted > 4 hours).
• Age 21 and above, able to understand the information regarding the study.
• Agreeable for randomization and signed consent form.

Exclusion Criteria:

• Patients who have known allergy to products of bovine origin or to the antibiotic, gentamicin.
• Pregnant women or breast-feeding mothers.
• No signed consent form.
• Intra-operative surgical finding inconsistent with inclusion criteria (lack of evidence of intra-peritoneal sepsis or duration of surgery < 4 hours).
• Patients having urgent abdominal surgery without indication of intra-peritoneal sepsis (such as patients with impending intestinal obstruction).