O3281: The Impact of Antibiotic Strategy on Outcomes in Surgically Managed Necrotizing Enterocolitis

Background: There is wide variation in the type and duration of antibiotic therapy used in infants following intestinal resection for necrotizing enterocolitis (NEC). While there is no strong evidence for fewer surgical infections with any strategy, there is a theoretical concern that excessively broad antibiotic coverage or duration might lead to opportunistic infection or resistance. We sought to evaluate postoperative antibiotic practices in a large population of patients with NEC and determine whether any regimens were associated with better outcomes.

Methods: The Pediatric Health Information Systems (PHIS) database was queried to identify patients with Bell stage 3 NEC who underwent an intestinal resection between July, 2016 and June, 2021. Patients who underwent resection more than 10 days after an initial procedure such as peritoneal drainage or decompressive laparotomy, died within 3 days, or had no documentation of antibiotic therapy were excluded. Data regarding demographics, preoperative physiology, operative management, post-resection antibiotic therapy (days of consecutive treatment, regimen), cutaneous or intraabdominal infection, fungal or antibiotic-resistant infection, length of stay and survival were collected.

Results: 241 patients were evaluated. 40 (16.6%) infants died at a mean of 48 days after the initial operation. Postoperative antibiotics were administered for a median of 13 days. In 48% of reporting hospitals, the mean duration of continuous antibiotic therapy exceeded 14 days. The most frequently used antibiotics were vancomycin and piperacillin/tozabactam. Antibiotic duration greater than 7 days was not associated with a lower incidence of infection. (Table 1) No antibiotic was associated with a lower incidence of infection, although patients who received ampicillin had significantly more infections, overall. Vancomycin was associated with a higher incidence of fungal infection and treatment with a parenteral anti-fungal medication. (Table 2) No antibiotic combination was used frequently enough to allow for assessment of efficacy.

Conclusion: The duration of antibiotic administration after resections for NEC varied substantially among hospitals. Antibiotic therapy that continued more than 7 days was not associated with a lower incidence of infection than shorter courses. Although this finding might be explained, in part, by continuation of antibiotics in some patients in response to infection, the absolute incidence of infection with 7 days or less of antibiotics was low. Although no single antibiotic was associated with a lower incidence of infection, there were significantly more infections in patients who received ampicillin and patients managed with vancomycin were at increased risk for fungal infection. Although most patients were treated with multiple antibiotics, no regimen was used frequently enough to permit assessment of outcomes. These data suggest that there is no benefit to more than 7 days of empiric antibiotic therapy after intestinal resection for NEC. Prospective studies may better define the efficacy and safety of various antibiotic regimens.