[Prevalence of ESBL strains in urinary tract infections in children in 1996 and 2004].

Ethiological agents in urinary tract infections and prevalence of bacterial strains producing extended spectrum of beta-lactamases isolated from urine of children with urinary tract infections were compared. Patients were hospitalized in Department of Pediatry, Pediatric Gastroenterology and Oncology of Medical University of Gdańsk in 1996 and 2004. Seventy bacterial strains isolated from urine in 1996 and 113 strains isolated in 2004 were analyzed. In both years Enterobacteriaceae were the most frequently encountered with Escherichia coli predominance. Proteus spp. (10.9%), Enterobacter spp. (7.1%), Klebsiella spp. (4.4%), and Enterococcus spp. (9.3%) were isolated rarely. Among bacteria isolated in 1996 there were no ESBL strains while in 2004 ESBL strains accounted for 11.5% of all urinary bacteria. Klebsiella oxytoca (25%) and Klebsiella pneumaniae (20%) produced ESBL most frequently. ESBL production was less frequent in Escherichia coli (13.2%) and Proteus mirablilis (10%). In conclusion, among bacteria isolated from urine of children with urinary tract infections G(-) strains producing ESBL were encountered only in recent years.