Which antibiotic regimen is best for paediatric appendicitis?

The use of antibiotics to treat paediatric appendicitis should target Escherichia coli and anaerobes, suggests a study. Two other bacteria are also present in about a fourth of the cultures, namely viridans group streptococci (VGS) and pseudomonas.

“Our data suggest that in a previously healthy population with a low rate of risk factors for antibiotic resistance, coverage of E. coli and pseudomonas infections with an aminoglycoside is adequate, while coverage of anaerobes may be achieved by adding metronidazole to the empiric regimen,” the researchers said.

This retrospective cohort study was carried out at the Soroka University Medical Center in Beersheba, Israel, between 2019 and 2021. A total of 379 children diagnosed with appendicitis were included.

The research team obtained data on the demographic characteristics, clinical presentation, risk factors, and surgical interventions of eligible participants. They also analysed bacterial cultures collected during the study period to identify microbiological profiles, including species prevalence and patterns of antibiotic resistance.

Of the surgical interventions performed, 53.6 percent were laparoscopic surgery, 44.9 percent laparotomy, and 1.6 percent both. Nearly half of the samples (49.3 percent) had positive cultures, 18.4 percent with a single bacterium, and 30.9 percent with polymicrobial growth. [Pediatr Infec Dis J 2025;44:826-831]

E. coli was the most prevalent isolate among positive cultures (75.4 percent), followed by Bacteroides spp. (41.2 percent), VGS (24.6 percent), and pseudomonas (23.0 percent). Enterococcus was seen in 3.2 percent of positive cultures, whereas anaerobic bacteria constituted 62.6 percent of isolates.

Several risk factors for antibiotic resistance were identified in <10 percent of cases, and these included previous hospitalization, surgery, or antibiotic treatment within the last month or year.

“Previous studies have shown that these factors impact bacterial nonsusceptibility rates,” the researchers said. “Notably, antibiotic treatment in the month preceding surgery is the factor most strongly associated with bacterial resistance, as reported in the literature.” [Ther Adv Drug Saf 2014;5:229-241; Epidemiol Infect 2021;149:e141]

“Consequently, the conclusions of the study are applicable mainly to populations with low rates of antibiotic resistance, highlighting the need for active surveillance on local and national levels to allow better appreciation of local antibiotic nonsusceptibility rates, which are crucial to the decision-making process,” according to the researchers.

Antibiotic treatment

E. coli was highly susceptible to gentamicin and ceftazidime (both 90.1 percent), ceftriaxone (89.4 percent), and carbapenems (100.0 percent), but not so to TMP/SMX (66.7 percent) and ampicillin (27.7 percent). Pseudomonas spp. showed high susceptibility to meropenem, ciprofloxacin (100.0 percent), and gentamicin (96.3 percent).

VGS, on the other hand, was susceptible to ceftriaxone and vancomycin (100.0 percent), penicillin (96.3 percent), and clindamycin and erythromycin (92.6 percent).

“The antibiotic regimes for children with complicated appendicitis vary across medical centres worldwide,” the researchers said. [J Am Coll Surg 2003;196:212-221; J Pediatr Surg 2003;38:236-242; Ir J Med Sci 2013;183:585-591; J Pediatr Surg 2010;45:2181-2185; Pediatrics 2016;138:e20154547]

“This variation reflects the diversity in current guidelines, which recommend a range of empirical regimens targeting Gram-negative, Gram-positive, and anaerobic pathogens,” they added. [Clin Infect Dis 2010;50:133-164]