Antimicrobial stewardship reduces SSI rate, number and severity of pancreatic fistulae following pancreatoduodenectomy

Gareth Morris-Stiff

Surgical site infections (SSIs) remain a major source of morbidity following pancreatoduodenectomy (PD). We noted a higher than anticpated incidence of SSI in our patients undergoing PD, and after an internal audit and detailed analysis of the microflora of SSIs, as well as a multidisciplinary discussion, the local prophylactic antibiotic policy was changed based on sensitivities to the bacteria isolated from postoperative wounds.

The hypothesis was that a targeted change in antibiotic prophylaxis would reduce the rate of SSIs. The aim of the current study was to analyse the results of a change in prescribing policy on SSI rates, and in addition, on the occurrence and severity of postoperative pancreatic fistulae (POPF) as this complication is often linked to the presence of an organ space SSI.

After implementing a change of prophylaxis policy from Cefalexin to Cefrtiaxone and Metronidzole, surgical residents were educated on the importance of compliance. A prospectively maintained departmental database was used to identify 200 consecutive patients undergoing PD, 100 pre- and 100 post institution of policy change. Incidence data relating to SSIs and POPF were obtained from the American College of Surgeons - National Surgical Quality Improveent Program (ACS-NSQIP) data set and the details of culture results and organism sensitivity extracted from the electronic medical record, as were details on the severity of fistulae.

Following change in the antibiotic prophylaxis policy, analysis of the NSQIP data revealed that the overall SSI rate fell from 29% to 16% (p=0.04). After excluding patients with a penicillin allergy (n=11) from the post-implementation cohort, the rates of SSI were compared in cases adherent (53/89) and non-adherent (36/89) to the new antibiotic policy. In this comparison, the SSI rates were 7.5% vs. 27.8% respectively (p=0.02), the later being comparable to the 29% in the pre-implementation cohort. The overall incidence of POPF fell from 37% to 24% (P=0.04), and furthermore, the rate of clinically significant fistula from 24% [21 Grade B and 3 Grade C] to 9% [9 Grade B] (p=0.03).

A change in the prescribing policy for prophylactic antibiotics prior to pancreatectomy, based on the local microflora, resulted in a significant reduction in the SSI rates following resection. In addition, antimicrobial stewardship also resulted in a statistically significant reduction in the overall incidence, as well as the incidence of clinically-significant POPF. The lack of complete compliance to policy has lead to the development of a fixed preoperative order set with only two antibiotic options for standard and penicillin-allergic patients. Following this additional venture, and further education on adherence to the policy a re-audit is in process.