Interaction between Escherichia coli P fimbrae Gene and Host Innate Immune Response in Urinary Tract Infection of Children

Abstract

Context: Uropathogenic E coli is the pathogen mostly associated with urinary tract infections. Disease severity determined by the balance between the pathogen and the innate immunity of the host, producing either acute pyelonephritis or asymptomatic bacteriuria. Aim: To investigate the impact of Escherichia coli p-fimbriae gene and the host chemokine receptor CXCR1 on disease severity in APN and ABU patients and to assess the impact of CXCR1 gene expression on recurrence risk of APN. Settings and design 50 children with APN (mean age 5.98±2.54 years) and 50 children with ABU; as controls (mean age 6.98±2.98 years). Methods: Detection of E. coli pap gene in E.coli isolates using conventional PCR, and quantification of CXCR1 gene expression using RT PCR. Statistical analyses: Independent-samples t-test, Chi-square (x2) test and Pearson's correlation coefficient (r) test. Results: pap gene was detected in 80% of the studied APN patients compared to only 16% of the ABU patients (p<0.05). comparing positive and negative pap APN patients regarding gender, number of recurrences, pus cells, RBCs, total leucocytes, CRP, bacteriuria, duration of fever, admission days and disease related renal scars, did not reveal any significant differences. CXCR1 gene expression was significantly (p<0.001) lower in APN patients (0.464±0.226) compared to their age matched ABU controls, (1.000±0.428). There were no significant correlations between 2^-ΔCT (CXCR1) and neither age, admission days or duration of fever. Conclusion Low CXCR1 gene expression may be a predisposing factor to APN as well as to increased risk of recurrence.