What is the most common source of bacteria in wound infection after groin hernia repair?

The Patient's Skin is the Most Common Source of Bacteria in Wound Infection After Groin Hernia Repair

The patient's skin is the most common source of bacteria in wound infection after groin hernia repair. 1

Pathophysiology of Surgical Site Infections (SSIs) in Groin Hernia Repair

Surgical site infections following groin hernia repair primarily originate from the patient's own skin flora. In clean surgical procedures like hernia repair, where the gastrointestinal, gynecologic, and respiratory tracts are not entered, Staphylococcus aureus from the exogenous environment or the patient's skin flora is the usual cause of infection 1.

The groin area presents unique considerations:

• The skin in the groin region can be colonized by both typical skin flora and enteric bacteria 1
• All surgical wounds are contaminated by bacteria, but only a minority develop clinical infection 1
• Infection occurs when host defenses fail to eliminate colonizers at the surgical site 1

Bacterial Sources in Groin Hernia Repair Infections

The source of bacteria in wound infections differs based on the type of surgical procedure:

1. Clean procedures (like standard groin hernia repair):

   • Primary source: Patient's skin flora, particularly Staphylococcus aureus 1
   • The groin skin specifically may also harbor enteric flora 1

2. Clean-contaminated or contaminated procedures:

   • Primary source: Endogenous microflora of the surgically resected organ 1
   • This would be relevant in cases where bowel resection is performed during hernia repair

Risk Factors for SSIs in Groin Hernia Repair

Several host factors increase the risk of developing SSIs:

• Age (especially ≥75 years)
• Malnutrition
• Diabetes
• Smoking
• Obesity
• Prior colonization with microorganisms (especially MRSA)
• Length of hospital stay or previous hospitalization
• Shock and hypoxemia
• Hypothermia 1

Infection Rates and Prevention

The incidence of SSIs after groin hernia repair is approximately 3.3-5.3% 2. While some studies suggest that antibiotic prophylaxis can reduce infection rates 3, 4, others have found no significant benefit 5, 6.

The 2017 World Society of Emergency Surgery guidelines recommend:

• In clean hernia repairs (CDC wound class I), short-term prophylaxis may be considered 1
• For procedures involving intestinal strangulation or bowel resection, 48-hour antimicrobial prophylaxis is recommended 1
• For peritonitis cases, full antimicrobial therapy is recommended 1

Management of SSIs After Groin Hernia Repair

When SSIs occur after groin hernia repair:

• Incisional SSIs require prompt and wide opening of the surgical incision 1
• Superficial incisional SSIs that have been opened can usually be managed without antibiotics 1
• Antibiotic therapy is recommended for SSIs with systemic inflammatory response syndrome or signs of organ failure 1

Conclusion

The patient's skin flora, particularly Staphylococcus aureus, is the predominant source of bacteria causing wound infections after groin hernia repair. This is consistent with the classification of standard hernia repair as a clean surgical procedure, where the main contamination source is the patient's own skin rather than the operating room environment, surgical instruments, or staff.