Pyelonephritis in infants is considered as a major factor for the formation of renal scar. To prevent recurrent pyelonephritis and renal damage, prophylaxis is extremely important. The aim of this study was to compare the effectiveness of probiotic and antibiotic prophylaxis or no-prophylaxis in infants with pyelonephritis and normal urinary tract.

Altogether 191 infants, who were diagnosed with acute pyelonephritis, proven to have normal urinary tracts and followed up for 6 months on prophylaxis, were retrospectively evaluated. According to the types of prophylaxis, the infants were divided into three groups [probiotics (Lactobacillus species), antibiotics (trimethoprim/sulfamethoxazole, TMP/SMX), and noprophylaxis]. The incidence of recurrent urinary tract infection (UTI) during 6 months after the development of pyelonephritis, main causative uropathogens, and its antimicrobial sensitivities were compared.

The incidence of recurrent UTI in the probiotic group was 8.2%, which was significantly lower than 20.6% in the no-prophylaxis group (P=0.035) and was not significantly different from 10.0% of the antibiotic group (P=0.532). The significant difference between the probiotic and no-prophylaxis groups was seen only in male infants (P=0.032). The main causative organism of recurrent UTI was Escherichia coli (E.coli), which was not different among the three groups (P=0.305). The resistance rate of E. coli to TMP/SMX was 100% in the antibiotic group, which was significantly higher than 25.0% in the probiotic group and 41.7% in the no-prophylaxis group (P=0.008).

Probiotic prophylaxis was more effective in infants with pyelonephritis and normal urinary tract than in those with no-prophylaxis. It could be used as a natural alternative to antibiotic prophylaxis.