Bladder urine microbiota in children with vesicoureteral reflux: preoperative values

Introduction. Urinary tract infections (UTIs) are prevalent among children, particularly those with anatomical anomalies such as vesicoureteral reflux (VUR). The diagnosis of VUR typically follows an episode of UTI, highlighting the importance of early detection of VUR in case of UTIs to prevent renal complications. The management of a first febrile UTI remains a subject of debate among medical professionals. Pediatricians often recommend diagnosing VUR after recurrent UTIs, while urologists advocate for early imaging and prophylaxis. Antibiotic prophylaxis (ABP) before surgery can reduce the risk of recurrent UTIs; however, it also induces antibiotic resistance and alters the microbiota.

Objective. To evaluate the microbiota of bladder urine in children before surgery for VUR.

Materials & methods. The study included 40 children (12 boys — group 1, 28 girls — group 2) diagnosed with MTCT after symptomatic urinary tract infection. The control groups were 18 healthy boys (group 3) and 16 healthy girls (group 4). Urine was collected and cultured using an expanded set of nutrient media (10–12) for culturing aerobic and anaerobic taxa of microbiota.

Results. The median age of VUR-patients in the study groups was 3.6 years. A statistically significant predominance of girls was observed (p < 0.001). The urine samples from VUR-children were unsterile, and a total of 27 taxa of microorganisms were detected. Among them, 16 taxa were aerobes, and 11 taxa were anaerobes. The dominant taxa differed between the groups: Enterobacterales, Peptococcus spp., and Anaerococcus spp. predominated in VURboys, while coagulase-negative staphylococci, Corynebacterium spp., and Peptococcus spp. dominated in VUR-girls. Most microorganisms were found in associations. The median bacteriuria level was mostly 10² CFU/ml. In total, 29 microbiota taxa with dominant aerobic-anaerobic relationships were identified in healthy children and VUR-patients. There were more significant correlations between different taxa of the urine microbiota in VUR-patients compared to healthy children.

Conclusion. Bladder urine from VUR-children contains aerobic and anaerobic bacteria. It is yet to be determined whether bacterial associations with a bacteriuria of 10² CFU/ml increase the risk of UTIs in VUR surgery, but urinary dysbiosis should be investigated as a possible risk factor for UTIs. Further studies are needed to justify the feasibility and suitability of selective ABP in the treatment of VUR.

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