Laboratory and imaging characteristics of children suffering from urinary tract infection from infancy to age five years who were hospitalized in paediatric department in Ziv medical center Safed children's Hospital in 2010-2019 in north of Israel

Background: Urinary tract infections (UTIs) are a common and potentially serious bacterial infection of childhood. UTI is the most common cause of hospitalization in children with high fever especially in infancy, which is more common to be the source for bacteremia in this age. In infancy, the disease is more common in boys and the incidence in girls increases with age, it has been found that uncircumcised children have a higher incidence of urinary tract infection. 30% of children who have had the first infection of pyelonephritis (inflammation of the kidney tissue) will develop a recurrent urinary tract infection when the infection occurs in the first year of life. The most common bacteria to cause these infections are Escherichia coli (E-coli), later Gram-negative bacteria (-) such as Klebsiella pneumonia and Proteus mirabilis, and gram-positive (+) bacteria such as Enterococci. ESBL + resistant bacteria have been found more as uropathogenic in recurrent urinary tract infections. Our aims in this study are to describe the epidemiological and microbiological properties and imaging of urinary tract infection in young children up to the age of five years. In our study, we examined the significance of reflux, its degree, and whether a cystography examination is necessary for any upper urinary tract infection. In addition, it was important to study different indices of inflammation (leukocytes, C-reactive protein test), renal ultrasound findings, and renal mapping of DMSA. Research methods: The study is retrospective that included infants and children up to the age of five who were hospitalized at Ziv Medical Center Safed in northern Israel in the pediatric department between 2010-2019, with the diagnosis of the first episode of urinary tract infection or recurrent episodes in the first five years of life. All children had symptoms and signs of urinary tract infection. The children underwent laboratory tests including cell blood count (CBC), kidney and electrolyte functions, C-reactive protein (CRP), blood culture, and urine sample. Following imaging of renal and urinary tract ultrasound, cystography was done after 4-6 weeks according to the protocol. Children underwent renal mapping with DMSA after 4 to 5 months of acute urinary tract infection. Results: The data showed a greater tendency for girls aged one year and older to have UTI. The average hospitalization time was 48 to 72 hours. We found no association with maternal smoking. Breastfed babies have lower rates of urinary tract infections in the first year. The most common uropathogens are E-coli, Klebsiella pneumonia, Proteus mirabilis, and Enterococci. Antibiotic resistance was observed in recurrent infections by E-Coli 20%, ESBL to 30%, And Klebsiella 45%. 30% to 40% developed recurrent urinary tract infections, recurrent infections were within two to four months after the first infection. In most children, empiric antibiotic therapy of Ampcilin and aminoglycoside was started. Most children underwent renal ultrasound, 35% had pathological imaging of hydronephrosis, and some with hydroureter. 40% of the children who underwent cystography had reflux with varying degrees, 60% of those who did mapping (DMSA) were pathological mapping (filling defect, scar). 18% of children with normal DMSA results had reflux. CRP, rates were found to be high in all children with pyelonephritis and reflux. Conclusion: Initiating empirical treatment of urinary tract infection is very important in preventing renal scar development. Recurrent urinary tract infections are characterized by various uropathogenic bacteria and a tendency to antibiotic resistance. Therefore, it is necessary to choose the appropriate antibiotic. As a renal ultrasound imaging available examination without radiation can be performed in the hospital. Cystography is not required in most cases of upper urinary tract infection. Kidney mapping by DMSA can reveal the additional value of kidney damage. Inflammatory indices including erythrocyte sedimentation rate (ESR) and CRP indicate the presence of renal tissue involvement such as Pyelonephritis. Keywords: Urinary tract infection; Pyelon