Implications of Bacteriological Study in Complicated and Uncomplicated Acute Appendicitis

Abstract BackgroundThe bacteriological sample in the presence of intraabdominal free fluid is necessary to adapt the antibiotherapy and to prevent the development of resistance. The aim of this study was to evaluate the differences between uncomplicated (UAA) and complicated acute appendicitis (CAA) in terms of bacterial culture results and antibiotic resistance, and to evaluate the predictors for complicated appendicitis.Material and methodsWe performed a single-centre, retrospective observational study of all consecutive patients who presented with appendicular peritonitis and underwent emergent surgery in a tertiary referral hospital in Brussels, Belgium, between January 2013 and December 2020. 268 patients were analysed in term of medical history, parameters at admission, bacterial culture, antibiotic resistance and postoperative outcomes.ResultsThe positive microbiological culture rate was significantly higher in CAA group (68.2 % vs. 53.4 %). The most frequently isolated bacteria in UAA and CAA cultures were E. coli (37.9 % and 48.6 %), bacteria from the Streptoccocus anginosus group (9.3 % and 7.8 %), and Bacteroides spp. (5 % and 13.1 %). The most commonly observed resistances were against ampicillin (28.9 % and 21.7 %) and amoxicillin/clavulanic acid (16.4 % and 10.5 %) in UAA and CAA, respectively. The predictors for complicated appendicitis were preoperative or intraoperative variables. Neither the culture results, the group of bacterial isolation nor the specific isolated bacteria predicted a complicated appendicitis.Conclusion CAA presented a higher rate of positive cultures with increased identification of Gram negative bacteria. There were not relevant differences in terms of antibiotic resistance.