Impact of peritoneal fluid culture findings on postoperative outcomes in pediatric patients with complicated appendicitis.

PURPOSE: Intraoperative peritoneal cultures for pediatric complicated appendicitis (CA) are important for informing postoperative antibiotic strategies. However, the specific impact of individual bacterial species remains unclear. In this study, we aimed to elucidate the association between peritoneal fluid culture findings and postoperative length of stay. METHODS: We reviewed the cases of 63 pediatric patients with CA, treated with appendectomy between 2018 and 2025, with peritoneal fluid samples submitted for bacterial culture. We extracted clinical data from medical records retrospectively and performed regression analyses to identify postoperative hospitalization-associated factors. RESULTS: Among the 63 patients, bacterial growth was observed in 46 (73.0%). Univariable analysis revealed significant associations between postoperative stay and C-reactive protein levels, perforation, and the number of detected bacteria. Specifically, Prevotella nigrescens, Escherichia coli, Parvimonas micra, and Streptococcus anginosus were associated with prolonged hospitalization. Among these, only P. nigrescens was not significantly associated with C-reactive protein levels, perforation, or number of detected bacteria, whereas the other 3 bacteria exhibited significant associations across certain parameters. CONCLUSION: Peritoneal fluid culture findings are associated with postoperative hospitalization in pediatric CA. Specific bacterial species may be associated with variations in postoperative outcomes.