Microbiological Spectrum and Antimicrobial Susceptibility Patterns in Pediatric Intra-Abdominal Infections Requiring Surgical Intervention

Background/Objectives: Intra-abdominal infections requiring surgical intervention represent a significant cause of morbidity in pediatric patients, often leading to prolonged hospitalization and increased antimicrobial exposure. Pediatric-specific data regarding microbiological profiles and antimicrobial susceptibility are limited, and treatment strategies are frequently extrapolated from adult guidelines. This study aimed to characterize pathogen distribution, antimicrobial resistance patterns, and clinical associations in pediatric intra-abdominal infections complicated by surgical site involvement. Methods: A retrospective observational study was conducted including children aged 0–16 years who underwent surgery for intra-abdominal infections with microbiological confirmation. Peritoneal fluid, pus, and other intraoperative or postoperative specimens were analyzed using standard microbiological techniques. Infections were classified as monomicrobial or polymicrobial, and antimicrobial susceptibility was assessed phenotypically. Associations between pathogens, patient age, underlying diagnosis, surgical procedures, and antibiotic susceptibility patterns were analyzed. Results: A total of 177 pediatric patients were included, predominantly male adolescents. Appendicitis was the most common diagnosis, followed by intra-abdominal abscesses. Gram-negative bacteria predominated, with Escherichia coli being the most frequently isolated pathogen. Polymicrobial infections were identified in approximately one-quarter of cases, particularly in abscesses and complicated appendicitis. The highest susceptibility rates were observed for cephalosporins and combination regimens, whereas penicillins demonstrated limited efficacy. Pathogen distribution and antimicrobial susceptibility varied significantly according to age group and clinical diagnosis. Conclusions: In pediatric patients, intra-abdominal infections requiring surgical management are mainly caused by Gram-negative and polymicrobial pathogens. Effective treatment relies on prompt surgical source control and empiric broad-spectrum antimicrobial therapy, followed by culture-guided de-escalation to support antimicrobial stewardship. Pediatric-specific microbiological data are essential for optimizing therapeutic strategies and improving clinical outcomes.