Background: Growing resistance to antibiotics among both community-acquired and hospital pathogens is making the treatment of most infections increasingly difficult. Therefore, the aim of our multi-center study was to determine the antimicrobial susceptibility of the most frequent aerobic microorganisms isolated from children with intraabdominal infections. Material/Methods:Bacterial pathogens were isolated from 256 consecutive patients treated in five large specialized hospitals in Poland from January 2001 to February 2002. Minimal inhibitory concentrations (MICs) of piperacillin, piperacillin-tazobactam, cefotaxime, ceftazidime and cefepime were determined by Etests. The production of extended spectrum β-lactamases (ESBL) was detected by a double-disk test.Results: Piperacillin-tazobactam was the most active agent against Enterobacteriaceae and Pseudomonas aeruginosa, inhibiting 92% and 78% of isolates respectively. Susceptibility of Enterobacteriaceae to cefotaxime, ceftazidime and cefepime was 73%, 73% and 87% respectively, and susceptibility of P. aeruginosa to both ceftazidime and cefepime was 76%. Extended-spectrum β-lactamases were detected in 56% Klebsiella sp. and 11.5% E. coli, but the vast majority of these isolates remained susceptible to piperacillin-tazobactam (MIC[sub]90[/sub]=12 mg/L and MIC[sub]90[/sub]=1 mg/L, respectively).Conclusions: Piperacillin/tazobactam remains a valuable therapeutic option in Polish pediatric patients with intraabdominal infections, due to its good activity against ESβL-producing organisms and P. aeruginosa.

Keywords: Bacteria, Aerobic - drug effects, Bacteria, Aerobic - isolation & purification, Klebsiella - drug effects, Klebsiella - enzymology, Klebsiella - isolation & purification, Penicillanic Acid - analogs & derivatives, Penicillanic Acid - pharmacology, Piperacillin - pharmacology, beta-Lactamases - analysis, Abdomen, Adolescent, Bacteria, Aerobic - isolation & purification, Bacterial Infections - microbiology, Child, Child, Preschool, Drug Resistance, Bacterial, Enterobacteriaceae - isolation & purification, Escherichia coli - isolation & purification, Infant, Newborn, Klebsiella - isolation & purification, Microbial Sensitivity Tests, Penicillanic Acid - pharmacology, Piperacillin - pharmacology, Poland, Pseudomonas aeruginosa - isolation & purification, beta-Lactamases - analysis