Accelerated bacteriological examination of urine and dialysate in the diagnosis of urinary tract infections in children

Abstract

Aim. To evaluate the feasibility of an accelerated method for determining the etiology of infections in urine, dialysate and residual antimicrobial activity by using laser light scattering technology.

Materials and methods. From January to September 2019, 106 urine samples and 42 dialysate samples from children aged 1–16 with various urinary pathologies and those on peritoneal dialysis underwent culture-based examination on an ALIFAX HB&L LIGHT analyzer (Alifax, Italy) using laser light scattering technology.

Results. Three hours after inoculation, 81 samples (76.4%) appeared to be negative and 25 samples (23.6%) proved to be positive. No microorganisms were detected in 38 dialysate samples (90.5%), two samples had Staphylococcus aureus (10⁴ CFU/ml), and one dialysate sample had Corynebacterium sp. and associations of Escherichia coli + Candida albicans + Staphylococcus haemolyticus, associated with peritoneal catheter colonization. Bacteriuria was caused by Enterobacterales in 39.3% (E. coli, Morganella morganii, Citrobacter amalonaticus, Enterobacter cloacae), non-fermenting gram-negative bacteria – in 14.3% (Pseudomonas aeruginosa, Ralstonia picketii, Oligella sp., Acinetobacter baumannii), Enterococcus sp. – 21.4%, S. haemolyticus, Staphylococcus epidermidis – 10.7%, Candida albicans – 3.6%, contamination: Streptococcus viridians, Corynebacterium sp. – 7.1%. Residual antimicrobial activity in urine was detected in 30.1% of patients.

Conclusion. The laser light scattering technology enables a minimal concentration of microorganisms to be detected in a smaller amount of urine or dialysate, which is very important for accelerated diagnosis of urinary tract infections and complications of peritoneal dialysis in children.