Intra-abdominal abscesses: Microbiological epidemiology and empirical antibiotherapy

Data on the microbiological epidemiology of Intra-Abdominal Abscesses (IAAs) are very scarce. We aimed to study the microbiological epidemiology of these infections in order to optimize empirical antibiotic therapy.

Between January 2015 and December 2020, we retrospectively analyzed all IAAs files in our hospital. Clinical and microbiological data such as antibiotic susceptibilities were collected.

We studied 243 IAA cases. All in all, 139 (57.2%) IAAs were healthcare-associated and 201 (82.7%) were drained. The highest risk situations for IAAs were appendicitis (n = 69) and diverticulitis (n = 37). Out of the 163 microbiologically documented infections, 136 (81.9%) were polymicrobial. Enterobacterales (n = 192, 36.1%), Enterococcus sp. (n = 84, 17.6%) and anaerobes (n = 66, 16.1%) were the most frequently identified bacteria. Gram-negative bacteria were susceptible to amoxicillin-acid clavulanic, piperacillin-tazobactam, cefotaxime, meropenem in 55.2%, 84.9%, 77.6% and 99.5% of cases, respectively. Concerning Gram-positive bacteria, the susceptibility rate was 81.8% for amoxicillin-clavulanic acid, piperacillin-tazobactam and meropenem, and decreased to 63.4% for cefotaxime.

This study highlights the polymicrobial profile of IAAs and their low susceptibility to amoxicillin and clavulanic acid. The piperacillin-tazobactam association remained the most appropriate empirical antibiotic therapy.