Abstract: Objective? To study the clinical features of complicated urinary tract infection (CUTI) in children, and to provide a reference for clinical and treatment of the disease. Methods? Clinical data of children with complex urinary tract infections from January 2015 to December 2019 were collected for retrospective analysis. Results? A total of 128 children were diagnosed, including 75 males and 53 females. Fever ( 111 cases, 86 . 7%) was the main manifestation of CUTI in infants, and vesicoureteral reflux ( 83 cases, 64 . 8%) was the most common. Compared with the group ≥ 3 years old, the proportion of vesicoureteral reflux was higher in the group < 3 years old, while the proportion of neurogenic bladder and renal insufficiency was lower, and the difference was statistically significant (P< 0 . 05 ). A total of 72 pathogenic bacteria were isolated, of which Escherichia coli was the first ( 17 strains, 23 . 6%). Drug sensitivity indicated that Escherichia coli was the most resistant to ampicillin ( 100%), but was more sensitive to meropenem, piperacillin/tazobactam and imipenem. Neurogenic bladder and vesicoureteral reflux were risk factors for urinary tract infection recurrence in children with CUTI (OR= 13 . 09 , 5 . 40 , P < 0 . 05 , respectively). The recurrence rate of urinary tract infection in the high-grade reflux group ( 76 . 6%) was higher than that in the low-grade reflux group ( 52 . 8%), and the recurrence rate in the low-grade reflux prophylactic antibiotics group ( 37 . 5%) was lower than that in the non-antibiotics group ( 83 . 3%), with statistically significant differences (P< 0 . 05 ). Thirty-five ( 35 ) cases of children with CUTI received surgical treatment to solve the urinary tract deformity, and the recurrence rate of urinary tract infection in children with CUTI after surgery ( 11 . 4%) was lower than that before surgery ( 37 . 1%), with statistically significant difference (P< 0 . 05 ). Conclusion? The clinical manifestations of CUTI in children are not typical, and fever with unknown cause is more common. Escherichia coli is the main pathogen. Vesicoureteral reflux and neurogenic bladder are high risk factors for recurrence. Prophylactic antibiotic therapy in children with low-grade vesicoureteral reflux and surgical treatment of urinary tract deformity significantly reduce the recurrence rate.

Key words: complex urinary tract infection;? clinical characteristics;? pathogenic bacteria;? prognosis;? child