[Aerobic etiology of acute appendicitis in adults. Multicenter study of abdominal sepsis in Argentina].

Antibiotic treatment for acute appendicitis is empirically chosen, based on epidemiological information. Resistance rates are different between regions and there are limited data on the situation in Argentina. As a part of a multicenter, observational study of abdominal infections, we performed the analysis of adult patients diagnosed with appendicitis, enrolled in 16 centers of 5 provinces, between Jan/01/2014 and Jun/30/2015. The aim was to analyze the prevalent aerobic pathogens, their resistance rates and the antimicrobial prescription pattern. On a total of 131 appendicitis cases analyzed, we found 184 aerobic pathogens (1.4 bacteria/episode): Escherichia coli 106 (57.6%), Klebsiella spp 16 (8.7%), Pseudomonas aeruginosa 19 (10.3%), Enterobacter spp. 2 (1%), other Gram negative bacilli 5 (2.7%); Enterococcus spp. 16 (8.7%) and other Gram positive cocci 20 (10.9%). The resistance rate of E. coli and enterobacteria to ampicillin/sulbactam was greater than 34% and greater than 31% to ciprofloxacin. However, the resistance of enterobacteria to piperacillin/tazobactam was 4.8%, to ceftriaxone 9.5%, to amikacin 3.6% and 8.2% to gentamicin. No resistance to carbapenems was found. The choice of quinolones or ampicillin/sulbactam for the treatment of appendicitis should be discouraged in our context, due to the high rates of resistance found in this prevalent etiology. Aminoglycoside-based treatments should be considered, given the findings of high antibiotic susceptibility and their low impact on the induction of resistance.