Evaluation of significant bacteriuria in pregnant women using quantitative real-time PCR

Abstract

Introduction. Urinary tract infections are the most common infections in obstetrics and gynecology. Bacteriological method to investigate urine is laborious and time-consuming, therefore development of accurate and rapid methods for the detection of significant bacteriuria is important. Objective. Evaluation of quantitative real-time PCR based approach for the detection of significant bacteriuria in pregnant women. Material and methods. A retrospective investigation of mid-stream urine samples obtained from pregnant women was performed. Urine culture was performed using quantitative method, and a case was considered as significant bacteriuria if ≥ 105 CFU/ml were detected. Urine samples were analyzed for main uropathogens / groups of uropathogens using quantitative multiplex real-time PCR. Diagnostic characteristics of PCR were computed relative to the results of urine culture. Results. In total, 896 urine samples were tested. Of them, significant bacteriuria was found in 28 cases (3%). The frequency of detection of Escherichia coli was 50%, Enterococcus spp. — 25%, Klebsiella spp. — 7%, Proteus spp. and S. saprophyticus 4% each, Streptococcus spp. — 14%. Sensitivity and specificity of the detection of significant bacteriuria using quantitative real-time PCR for the majority of bacterial species / groups were 99% to 100%. Sensitivity and specificity of the quantitative real-time PCR based method were 96% and 98%, respectively. Conclusions. Prevalence of significant bacteriuria among pregnant women is 3%. Half of the uropathogens isolated from pregnant women with bacteriuria are E. coli. Sensitivity and specificity of quantitative PCR for the detection of significant bacteriuria are 96% and 98%, respectively.