Management and Microbiology of Perforated Appendicitis in Pediatric Patients: A 5-Year Retrospective Study

Abstract

Introduction: This study aims to assess the current epidemiology and microbiology of perforated appendicitis, how antibiotic choice and duration correlate with meaningful clinical outcomes, and whether serial white blood cell (WBC) counts provide clinical value. Methods: Five-year retrospective cohort study, 2015-2019, among 333 consecutive children, ages 0-18 years, treated at St. Louis Children's Hospital for perforated appendicitis. Main outcomes included length of stay (LOS), postoperative abscess formation, and readmission. Statistical analysis was performed with uni-and multi-variate analyses. Results: Intra-abdominal cultures most commonly grew Bacteroides fragilis (52%) and Escherichia coli (50%). Patients who initially received broad-spectrum antibiotics (meropenem, piperacillin-tazobactam, fourth-generation cephalosporins) for perforated appendicitis had greater rates of postoperative abscess formation (25% vs. 12%, p \ 0.01) and LOS (7.0 vs. 5.7 days, p \ 0.01). Similarly, antibiotics at time of discharge were associated with greater postoperative abscess formation (22% vs. 9%, p \ 0.01) and LOS (6.4 vs. 5.6 days, p = 0.02). However, discharge with strictly oral antibiotics was not correlated with greater LOS, postoperative abscess formation, or readmission rates compared to discharge without antibiotics. Serial WBC counts had no predictive value for LOS, postoperative abscess formation, or readmission. Conclusions: Bacteroides fragilis and E. coli were the most common intra-abdominal microbes for perforated appendicitis among our cohort. In non-critically ill children, the routine use of broad-spectrum antibiotics or continuation of antibiotics beyond discharge was not correlated with improved clinical outcomes. Additionally, WBC counts were not correlated with meaningful clinical outcomes.

Association of the Bacteria of the Vermiform Appendix and the Peritoneal Cavity with Complicated Acute Appendicitis in Children

“…Our results agreed with those of most of the studies, with E. Coli, P. aeruginosa and Streptococcus spp being the most frequent pathogens [18,[34][35][36][37][38][39][40]48]. In perforated appendicitis, Streptococcus spp and P. aeruginosa were also common in the lumen, while Streptococcus spp and P. aeruginosa in the peritoneal cavity.…”

“…Therefore, the knowledge of the most common bacteria which are implicated in this process is of great value. The bacterial flora of the appendix and/or the peritoneal cavity in children with acute appendicitis has been described in numerous studies [18,[34][35][36][37][38][39][40][41][42][43][44][45][46]. The association between certain bacteria and the stage of appendicitis has been investigated as well [18,34,35,39,42,43,45,46].…”

“…The association between certain bacteria and the stage of appendicitis has been investigated as well [18,34,35,39,42,43,45,46]. Traditional culture techniques [18,[34][35][36][37][38][39][40], culture-independent methods like rRNA or rDNA gene sequencing [41][42][43][44][45], or both [46], have been used to investigate the microbial content and its role in the different grades of appendicitis. Supporters of the gene sequencing studies reported that traditional cultures failed to identify the majority of the microorganisms [39], as children with acute appendicitis presented an abundance of the genera Fusobacteria and a decrease of the genera Bacteroides, compared to controls [42,44].…”

“…Based on the theory that gene sequencing techniques cannot distinguish between viable and non-viable bacteria, other studies preferred traditional cultures, after collecting fluid from the peritoneal cavity [18,[34][35][36][37][38][39][40]. Schülin, et al collected samples from the lumen of the appendix [46].…”

“…E. coli is reported as the most common microorganism, followed by P. aeruginosa, Bacteroides spp and Streptococcus spp [28,[34][35][36][37][38][39][40]46]. No statistically significant association has ever been reported between specific bacterial strains and the different stages of appendicitis, although in some studies P. aeruginosa was often identified in gangrenous and most severe forms of appendicitis [18,46].…”