Follow-up after infants younger than 2 months of age with urinary tract infection in Southern Israel: Epidemiologic, microbiologic and disease recurrence characteristics

Background: The timing of most recurrences after neonatal urinary tract infection is during the first year of life, with peak incidence 2-6 months after the initial infection. Information on the microbiologic characteristics of recurrent urinary tract infection episodes in relation to the microbiology of the initial episodes is limited. Objectives: To analyze the epidemiologic/microbiological characteristics of 1st and recurrent urinary tract infection in infants <2 months of age. Methods: A retrospective study including all infants <2 months of age with urinary tract infection admitted during 2005-2009 and followed till the age of 1 year. Results: 151 neonates were enrolled (2.7% of all 5617 febrile infants <2 months of age admitted). The overall incidence of urinary tract infection occurring during the first 2 months of life was 151/73,480 (0.2%) live births during 2005-2009 in southern Israel (2.1 cases/1000 live births). One pathogen was isolated in 133 (88.1%); Escherichia coli, Klebsiella spp., Enterococcus spp., Morganella morganii, Proteus spp., and Enterobacter spp. represented the most common pathogens (57.9%, 12.2%, 7.9%, 6.7%, 6.1%, and 5%, respectively). Trimethoprim/sulfamethoxazole, ampicillin, and cefuroxime-axetil were the most commonly recommended prophylactic antibiotics (45%, 13.2%, and 8%, respectively). Twenty-three recurrent urinary tract infection episodes were recorded in 20 (13.2%) patients; 6/23 (26%) were diagnosed within one month following 1st episode. E. coli was the most frequent recurrent urinary tract infection pathogen (12/23, 52.2%). No differences were recorded in E. coli distribution between first urinary tract infection vs. recurrent urinary tract infection. Seventeen (74%) recurrent urinary tract infection episodes were caused by pathogens different (phenotypically) from those isolated in 1st episode. Recurrent urinary tract infection occurred in 25.0%, 8.3%, and 0 patients recommended trimethoprim/sulfamethoxazole, cefuroxime-axetil, or amoxicillin prophylaxis, respectively. Conclusions: (1) The study determined the incidence of urinary tract infection in febrile infants <2 months of age in Southern Israel; (2) E. coli was responsible for the majority of first and recurrent urinary tract infection; (3) recurrent urinary tract infection was caused mostly by pathogens different than the pathogens isolated at initial episode.