A surgical site infection (SSI) is defined as ‘infection related to an operative procedure that occurs at or near the surgical incision within 30 days … or within 90 days if prosthetic material is implanted’.1

Causative organisms are usually skin flora, including strep species, Staph aureus and coagulase negative staph. Commensals from any mucosal surface involved will also be present.

Patient risk factors for surgical site infection are predictable; smoking, obesity, diabetes, malnutrition, immunosuppression, old age. Patients with evidence of active infection prior to elective surgical procedures should complete treatment for the infection prior to surgery.

Smoking cessation reduces the risk of wound complications, even if only achieved within six weeks of the surgery.2

Emergency procedures have a higher rate of surgical site infections. Open procedures have higher rates than minimally-invasive and laparoscopically-assisted procedures. Measurement of individual surgeon’s SSI rates can reduce infection rates.3

Protective surgical factors include preoperative antibiotics, perioperative infection control, surgical technique and avoidance of surgery, where possible, in patients with concurrent infection.4

There is no evidence for bowel preparation in reducing SSIs unless the colon is to be operated on directly.5

Table 1. Surgical sites vary widely in infection risk.

Bowel 4.3–10.6%
Gastric/liver/pancreas 2.8–12.3%
Coronary 3.3–3.7%
Joint 0.7–1.7%
Eye 0.14%
Gynaecology 2–18%
Caesarean section 3.4–4.4%
(emergency 3–15%)


Antibiotics are used to reduce the volume of micro-organisms present at the surgical site at the time of the procedure.6 7 For adequate drug levels in the tissue at the time of incision, antibiotics should be given within 60 minutes of the start of surgery.8 There is some evidence that repeat dosing may be effective in prolonged surgeries (more than four hours) or with excessive blood loss (1.5 L).9

Compliance with preoperative antibiotics is improved using surgical ‘time-outs’.10

Suggested preoperative antibiotic regimes for gynaecology surgery:11 12 13

  • Augmentin 1.2 G IV (ceftriaxone 2 G IV if penicillin allergic, gentamicin 3 mg/kg IV
    if anaphylactic)
  • Cefazolin 2 G IV plus metronidazole 500 mg IV (gentamicin and metronidazole if penicillin anaphylactic)

There are no recommendations for prophylactic antibiotics in IUCD insertion, hysteroscopy, diagnostic laparoscopy LLETZ or HSG unless prior infection is suspected.14

Caesarean section:

  • Ceftriaxone 1 G IV (teicoplanin 800 mg IV and gentamicin 3 mg/kg IV if allergic)
  • Cefazolin 2 G IV (clindamycin 600 mg IV as 20-minute infusion if anaphylactic

The antibiotics should be given 30 minutes before the caesarean – ideally at the time of cannulation – to achieve bactericidal levels prior to incision.15 16 This reduces the risk of postoperative endometritis and surgical site infection by approximately 50 per cent. In the past, concerns of drugs reaching the fetus meant that antibiotics were delayed until after cord clamping, but trials have not observed any increase in neonatal sepsis rates among patients randomised to preincision antibiotics. Whether the magnitude of benefit is the same for elective as emergency caesarean section is unclear.17 18

Infection control practices are evidence based and reduce SSIs by up to 40 per cent.19 These practices include:

  • Hand hygiene pre-operative ‘scrubbing’ by surgical team and hand washing by anaesthetic team.
  • Surgical attire with scrubs, gloves and shoe covers/hats/masks that should not be worn outside the operating theatre.
  • Hair removal should be done using clippers rather than a razor; however, any preoperative hair removal actually increases infection risk.
  • Skin disinfection – there is no firm evidence that preoperative patient bathing reduces SSIs.20 Preoperative washing by patients with regimes using chlorhexidine wash are commonly used but not proven to be beneficial or cost effective.
  • Systematic reviews show that skin cleansing with chlorhexidine reduces skin flora more than povidone-based preparations and should be applied in horizontal stripes for best effect.21

Good surgical technique reduces the risk of SSIs:22 23

  • Minimise use of electrosurgical devices to reduce the volume of tissue necrosis. Areas of necrosis act as a nidus for infection.
  • Avoid excessive traction on the wound edges – ring-shaped wound protection devices are available for atraumatic tissue retraction and to stop wound edges drying out.24
  • Avoid excessive tension on sutures to reduce tissue ischaemia
  • Effective haemostasis to reduce the need for blood transfusion
  • Keep tissues moist

There is no real data to show differences in SSIs with different types of dressing postoperatively or with use of topical and local antibiotic delivery methods.25

Other perioperative measures that may reduce SSIs include:26 27 28 29

  • Perioperative normothermia seems to be better than hypothermia for avoiding SSIs.
  • Limiting of traffic through the operating theatre as, unsurprisingly, the number of people and frequency of door openings is related to the number of airborne particulates.
  • Good glucose control – perioperative hyperglycaemia is associated with higher rates of infection.
  • High flow oxygenation, though robust evidence is lacking.
  • Avoidance, where possible, of blood transfusion.