Appendicular Versus Non-Appendicular Community-Acquired Intra-Abdominal Infections: A Post-Hoc Analysis of the PERICOM Multicenter Study.

Background

Community-acquired intra-abdominal infections (CA-IAIs) exhibit significant clinical heterogeneity. However, most studies focusing on CA-IAIs do not stratify comparisons by infection site.

Methods

This post hoc analysis of the prospective multicenter PERICOM cohort (13 French university hospitals, April 2018 to February 2019) included adult patients with CA-IAIs requiring surgical management. We compared clinical characteristics, microbiology, and outcomes between appendicular and non-appendicular sites. Secondary analyses assessed the impact of Enterococcus spp., Pseudomonas aeruginosa, or fungal documentation, and the theoretical coverage of empirical antibiotic regimens.

Results

Of the 205 patients, 86 (42%) had appendicular and 119 (58%) had non-appendicular CA-IAIs. Appendicular CA-IAIs involved younger patients with fewer comorbidities and were followed by fewer major postoperative complications (Clavien-Dindo score ≥ 3: 10% versus 43%, p < 0.001) and no deaths (0% versus 12%, p < 0.001). Among 118 culture-positive patients, appendicular CA-IAIs showed higher rates of non-fermenting Gram-negative bacilli (25% versus 10%, p = 0.046) and anaerobes (53% versus 28%, p = 0.008) and were more often polymicrobial (76% versus 55%, p = 0.020). Conversely, Staphylococcus spp. (0% versus 9%, p = 0.036) and fungal co-infection (0% versus 12%, p = 0.010) were confined to non-appendicular CA-IAIs. Furthermore, Enterococcus spp. documentation (24/118, 20%) identified patients with greater admission severity and higher 28-day mortality (33% versus 2%, p < 0.001). Amoxicillin-clavulanic acid plus gentamicin covered the isolates of 92% of patients versus 61% for third-generation cephalosporin plus metronidazole (p < 0.001), a difference identical in both appendicular and non-appendicular sites.

Conclusions

Appendicular and non-appendicular CA-IAIs appear to be distinct entities, supporting stratified management. Future guidelines should consider site-specific strategies, therapeutic individualization, and the integration of CA-IAI ecology.