According to the Centers for Disease Control and Prevention (CDC), a surgical site infection (SSI) is an infection that occurs after surgery at the site where the surgery was performed. The prevalence of SSIs is difficult to obtain and is probably underestimated, as many SSIs occur after the patient has been discharged from hospital and are not taken into account. SSIs are responsible for an increase in length of stay, mortality and costs. Their prevention is therefore essential in the operating theater, and has been the subject of recommendations recently updated by the CDC. The first line of prevention is the administration of prophylaxis antibiotic adapted to the surgical procedure, administered within a specific timeframe in order to achieve an effective bactericidal concentration in the tissues at the time of the surgical incision. In France, in the United States and for the WHO, the recommended first line of antibiotic prophylaxis is most often an agent from the beta-lactam family, a penicillin or a cephalosporin, with the exception of ophthalmological surgery. No strategy is described for the management of patients with a reported allergy to penicillin, apart from the recommendation of therapeutic alternatives.

The use of a decision-making strategy in the operating theater for patients with a reported allergy to penicillin therefore appears necessary and is recommended by experts. In the intraoperative context, the application of a strategy would make it possible to guide the use of cephalosporins, without removing the "penicillin allergy" label from the patient, but by proposing an alternative via the use of a cephalosporin depending on the probability of the risk of a real allergy to penicillin, according to the description of the former reaction.

According to the Centers for Disease Control and Prevention (CDC), a surgical site infection (SSI) is an infection that occurs after surgery at the site where the surgery was performed. The prevalence of SSIs is difficult to obtain and is probably underestimated, as many SSIs occur after the patient has been discharged from hospital and are not taken into account. SSIs are responsible for an increase in length of stay, mortality and costs. Their prevention is therefore essential in the operating theater, and has been the subject of recommendations recently updated by the CDC. The first line of prevention is the administration of prophylaxis antibiotic adapted to the surgical procedure, administered within a specific timeframe in order to achieve an effective bactericidal concentration in the tissues at the time of the surgical incision. In France, in the United States and for the WHO, the recommended first line of antibiotic prophylaxis is most often an agent from the beta-lactam family, a penicillin or a cephalosporin, with the exception of ophthalmological surgery. No strategy is described for the management of patients with a reported allergy to penicillin, apart from the recommendation of therapeutic alternatives.

The use of a decision-making strategy in the operating theater for patients with a reported allergy to penicillin therefore appears necessary and is recommended by experts. In the intraoperative context, the application of a strategy would make it possible to guide the use of cephalosporins, without removing the "penicillin allergy" label from the patient, but by proposing an alternative via the use of a cephalosporin depending on the probability of the risk of a real allergy to penicillin, according to the description of the former reaction.

The main objective is to assess the impact on first and second generation cephalosporins prescription rate of a decision tree designed to guide the prescription of first and second generation cephalosporins in patients with a self-reported allergy to penicillin.

Inclusion Criteria:

• Age >= 18 years;
• Patients with a good French understanding
• Who declare themselves allergic to penicillin and who have not benefit from an allergy work-up to explore their allergies and possible therapeutic alternatives;
• Requiring antibiotic prophylaxis with either first or second generation cephalosporins for elective or emergency surgery.

Exclusion Criteria:

• Refusal to sign informed consent
• Patient under legal protection ;
• Pregnant women;
• Patient scheduled for surgery requiring first-line antibiotic prophylaxis with an agent other than first and second generation cephalosporins (such as amoxicillin/clavulanate or vancomycin) according to the recommendations of the French Society of Anaesthesia and Intensive Care (SFAR) in one of the investigating centres;
• Patient declaring an allergy to antibiotics other than penicillins.
• Not affiliated to a social security scheme