Surgical site infection: signs, prevention and treatment after an operation

Most operations involve making a cut in the skin. An NHS orthopaedic hospital patient guide explains that most wounds heal without problems, but a wound can become contaminated by bacteria from the skin or environment, which may get into the body and cause an infection. A guide from a London NHS trust says surgical wound infections happen when germs enter the cut the surgeon makes through the skin.

NICE defines a surgical site (wound) infection as a surgical wound with local signs and symptoms of infection such as heat, redness, pain and swelling and, in more serious cases, systemic signs such as fever or a raised white blood cell count. It adds that infection may prevent healing, causing the wound edges to separate, or may cause an abscess to form in deeper tissues.

The London trust guide says most surgical wound infections are skin infections that can sometimes spread to deeper tissues, and that some types of surgery carry more risk than others. Infections are more likely after surgery on parts of the body that have lots of germs, such as the gut.

The patient guides are consistent about the signs. They also say that infections can develop after you have left hospital, so you need to know what to look for at home.

• Redness, soreness, swelling and heat around the wound.

• The wound becoming more painful to touch.

• Green or yellow pus coming from the wound, which may be smelly.

• The edges of part of the wound separating, or the wound opening.

• Feeling generally unwell, feverish or having a raised temperature.

One orthopaedic hospital guide says a wound infection can appear any time within a few days up to 3 to 6 weeks after the operation, until the wound has healed, and that if metalwork has been put in, signs of infection might appear after several months. That hospital monitors patients for surgical site infection up to a year after their operation.

The London trust guide gives a shorter typical window of 2 to 3 days after surgery until the wound has healed, usually 2 to 3 weeks, while also noting that sometimes infection appears several months later. The pattern depends on the type of operation and whether implants were used.

The London trust guide says if you have a problem with your wound or any of these symptoms, contact your hospital doctor or a GP straight away, because it is important to treat any infection as soon as possible to stop it getting worse. The orthopaedic hospital guide adds that if you have been discharged and develop one or more symptoms you should contact your GP or attend your local hospital unless told to contact your surgical team, and other options include local urgent care or walk-in centres.

Both guides advise not removing your dressing or touching your wound, wound drain or dressing unnecessarily, because you could accidentally spread germs from your fingers to the wound. If you do need to touch it, wash your hands properly first.

NICE guideline NG125 sets out measures across the whole pathway. Before surgery it advises patients to shower or bathe with soap the day before or the day of surgery, to consider nasal mupirocin with a chlorhexidine body wash before procedures in which Staphylococcus aureus is a likely cause of infection, and not to use hair removal routinely. If hair has to be removed it advises electric clippers with a single-use head on the day of surgery and not razors, because razors increase the risk of infection.

It recommends antibiotic prophylaxis before clean surgery involving the placement of a prosthesis or implant, clean-contaminated surgery and contaminated surgery, and advises against routine prophylaxis for clean non-prosthetic uncomplicated surgery. During surgery it recommends antiseptic skin preparation, with an alcohol-based chlorhexidine solution as the first choice unless contraindicated, and maintaining the patient’s temperature, oxygenation and perfusion.

After surgery NICE advises using an aseptic non-touch technique for dressings, sterile saline for wound cleansing up to 48 hours, and says patients may shower safely 48 hours after surgery. Patient guides also describe screening for MRSA before or on admission and treating it before an operation if found.

NICE says that when surgical site infection is suspected by the presence of cellulitis, the patient should be given an antibiotic that covers the likely causative organisms, taking into account local resistance patterns and microbiological test results. It advises against using Eusol and gauze or dextranomer or enzymatic treatments for debridement of infected wounds.

The London trust guide says that if a nurse or doctor thinks you have an infection, they might take a swab of the wound surface and send it to the laboratory, and you might be treated with antibiotics. An orthopaedic hospital guide advises taking the whole course of any antibiotics as instructed. Wounds left open to heal need appropriate dressings, and NICE suggests involving a tissue viability nurse for advice.

Most superficial infections settle with prompt antibiotics and wound care. Deeper infections, particularly where an implant is involved, may need further surgery and more prolonged treatment, which is why early reporting of symptoms matters.

NHS surgical teams, practice nurses and GPs all take part in monitoring wounds after discharge, and some hospitals use digital wound monitoring in which patients send photographs. The signs and actions described here apply whichever hospital or clinic carried out your operation.