Objective:To explore the diagnostic value and clinical application of metagenomic next-generation sequencing (mNGS) technology in pediatric urinary tract infections (UTI).Methods:In this retrospective study, the clinical data of children with UTI admitted to the Department of Nephrology, Children′s Hospital, Capital Institute of Pediatrics, from March 2023 to March 2024 were collected.The positive detection rates, timeliness, and consistency of mNGS technology were compared with those of urine culture.Measurement data were subject to test of normality.The independent sample t test, Chi-square test or Fisher′s exact probability test were used for comparison between groups. Results:A total of 193 patients were included.The positive detection rate of urine culture was 36.3% (70/193).Among 42 patients who underwent mNGS testing, 37 cases (88.1%) tested positive.The positive detection rate of mNGS was significantly higher than that of urine culture ( χ2=37.357, P<0.001).It took significantly less time to report mNGS results than to report urine culture results ( Z=3.524, P<0.001).In the 42 cases that underwent mNGS testing, 5 cases (11.9%) were negative for urine pathogens by both methods, and 21 cases (50.0%) were positive by mNGS but negative by urine culture.Among the remaining 16 cases (38.1%) positive by both mNGS and urine culture, 14 cases (33.3%) achieved fully matching results, 1 case (2.4%) was fully mismatched, and 1 case (2.4%) was partially matched.Comparison of the positive detection rate and the duration of anti-infective treatment prior to specimen collection between urine culture and mNGS showed that the median durations for urine culture and mNGS positivity were 5 and 20 days, and the difference was statistically significant ( χ2=0.537, P<0.001). Conclusions:mNGS technology has high sensitivity for diagnosing pathogens in pediatric UTI.Compared with urine culture, mNGS provides good consistency and significantly shortens the detection time.The positive detection rate is less affected by antimicrobial treatment.For children with UTI, especially those who have failed empirical anti-infective treatment and whose pathogen cannot be identified by urine culture, mNGS testing is recommended as early as possible.

Objective To investigate serum β2-MG, sCHE, and PSGL-1 expression in patients with esophageal cancer and their relationship to lung infection after mediastinoscopy. Methods A total of 118 patients with esophageal cancer were selected and divided into infected and uninfected groups according to whether they developed lung infection after surgery. An automatic microbiological identification system was used to detect the pathogenic bacteria of lung infection. ELISA was used to detect the levels of β2-MG, sCHE, and PSGL-1. Multivariate logistic regression was used to analyze the influencing factors of postoperative lung infection in patients with esophageal cancer. ROC curves were plotted to analyze the assessment value of serum β2-MG, sCHE, and PSGL-1 on postoperative lung infection. Results Fifty-two strains of bacteria were isolated from the sputum of 38 patients with postoperative lung infections, and these included 35 (67.31%) Gram-negative, 14 (26.92%) Gram-positive, and 3 (5.77%) fungal strains. The difference in long-term smoking history between the infected and uninfected groups was statistically significant (P<0.05). Serum β2-MG and PSGL-1 levels were significantly higher and sCHE levels were significantly lower in the infected group than in the uninfected group (P<0.05). Serum β2-MG and PSGL-1 levels were sequentially higher (P<0.05) and sCHE levels were sequentially lower (P<0.05) in the mild, moderate, and severe lung infection groups. Long-term smoking history, β2-MG, and PSGL-1 were risk factors affecting postoperative lung infection in patients with esophageal cancer (P<0.05), and sCHE was a protective factor (P<0.05). The AUCs of serum β2-MG, sCHE, and PSGL-1 for assessing postoperative lung infections were 0.807, 0.845, and 0.800, respectively, and the AUC of the three combined factors for assessing postoperative lung infections was 0.954, which was superior to that assessed individually (Z_{combination vs. β2-MG}=2.576, Z_{combination vs. sCHE}=2.623, Z_{combination vs. PSGL-1}=2.574, all P<0.05). Conclusion The serum levels of β2-MG and PSGL-1 increase and the sCHE level decreases in patients with esophageal cancer and postoperative pulmonary infection, which are also related with lung infection. Combined testing can improve the evaluation value of postoperative pulmonary infection in patients.

Objective:To explore the diagnostic value and clinical application of metagenomic next-generation sequencing (mNGS) technology in pediatric urinary tract infections (UTI).Methods:In this retrospective study, the clinical data of children with UTI admitted to the Department of Nephrology, Children′s Hospital, Capital Institute of Pediatrics, from March 2023 to March 2024 were collected.The positive detection rates, timeliness, and consistency of mNGS technology were compared with those of urine culture.Measurement data were subject to test of normality.The independent sample t test, Chi-square test or Fisher′s exact probability test were used for comparison between groups. Results:A total of 193 patients were included.The positive detection rate of urine culture was 36.3% (70/193).Among 42 patients who underwent mNGS testing, 37 cases (88.1%) tested positive.The positive detection rate of mNGS was significantly higher than that of urine culture ( χ2=37.357, P<0.001).It took significantly less time to report mNGS results than to report urine culture results ( Z=3.524, P<0.001).In the 42 cases that underwent mNGS testing, 5 cases (11.9%) were negative for urine pathogens by both methods, and 21 cases (50.0%) were positive by mNGS but negative by urine culture.Among the remaining 16 cases (38.1%) positive by both mNGS and urine culture, 14 cases (33.3%) achieved fully matching results, 1 case (2.4%) was fully mismatched, and 1 case (2.4%) was partially matched.Comparison of the positive detection rate and the duration of anti-infective treatment prior to specimen collection between urine culture and mNGS showed that the median durations for urine culture and mNGS positivity were 5 and 20 days, and the difference was statistically significant ( χ2=0.537, P<0.001). Conclusions:mNGS technology has high sensitivity for diagnosing pathogens in pediatric UTI.Compared with urine culture, mNGS provides good consistency and significantly shortens the detection time.The positive detection rate is less affected by antimicrobial treatment.For children with UTI, especially those who have failed empirical anti-infective treatment and whose pathogen cannot be identified by urine culture, mNGS testing is recommended as early as possible.

Objective:To evaluate the efficacy and safety of rituximab (RTX) in children with steroid resistant nephrotic syndrome (SRNS).Methods:The was a retrospective observational study. A retrospective analysis was conducted on the clinical data of 14 children with SRNS who received RTX treatment in the Department of Nephrology, Children's Hospital Affiliated to Capital Institute of Pediatrics from July 2021 to August 2023. The changes in urinary protein content, renal function, serum albumin, immunoglobulin and other indicators before and after RTX medication were compared to evaluate the clinical efficacy and safety of RTX treatment for SRNS.Results:A total of 14 children with SRNS were selected for this study, with a male to female ratio of 6:8. The age of onset of kidney disease was (4.36±3.12) years, and 8 of them underwent kidney biopsy. Among them, 6 cases showed focal segmental glomerulosclerosis in renal pathology, and 2 cases showed minimal change disease. The age of 14 children who first used RTX was (8.45±3.98) years old, with a dose of 375 mg/m 2 and a maximum dose of 500 mg. The number of children who had used 2, 3, 4, and 5 doses of RTX was 6, 6, 1, and 1, respectively. RTX was administered orally with compound sulfamethoxazole to prevent infection. Glucocorticoids and immunosuppressants were discontinued 4.0(2.5, 6.5) months after the first dose of RTX. The median follow-up time was 10.5(6.0, 18.3) months. By the end of the 3-month, 6-month, and follow-up endpoints, the complete remission rates of kidney disease in the children were 100.0%(14/14), 85.7%(12/14), and 64.3%(9/14), respectively. Five children experienced kidney disease recurrence. Compared with before the first dose of RTX treatment, the serum albumin and height significantly increased, while body mass index significantly decreased at the end of follow-up (all P<0.05). There was no statistically significant difference in urinary protein content, renal function, and IgG (all P>0.05). During the RTX treatment, all 14 children did not experience any infusion reaction, and there were no serious infections during follow-up. One case was diagnosed with hypogammaglobulinemia. Conclusions:RTX can improve the remission rate and recurrence rate of SRNS children, reduce the dosage of glucocorticoids and related drug untoward reaction, significantly improve patient height and BMI, with minimal side effects. Especially for SRNS patients who cannot be relieved by the combination of glucocorticoids and immunosuppressants, RTX may be considered.

Objective:To analyze the clinical characteristics of renal abscess in children and provide suggestions for early diagnosis and treatment.Methods:The clinical data including general information, laboratory data, imaging results, treatment and prognosis of 20 pediatric patients with renal abscess admitted to the Department of Nephrology, Capital Center for Children's Health Capital Medical University were analyzed retrospectively.Results:A total of 8 males and 12 females were enrolled. The age of onset was 3.0 (0.8, 9.0) years. All cases had fever. Six cases presented with abdominal pain, 6 cases had poor appetite, 5 cases had vomiting and 5 cases urinary tract irritation symptoms. Laboratory data showed elevated white blood cells 20.4 (17.4,26.3)×10 9/L, C-reactive protein 126 (77, 154)mg/L, erythrocyte sedimentation rate 60 (41,73) mm/1 h in 20 cases and procalcitonin 4.7 (1.2,33.5)μg/L in 10 cases. Totally 18 cases had pyuria. Urine culture was positive in 8 cases. Enterococcus faecium and Pseudomonas aeruginosa was detected in 2 cases. Klebsiella pneumoniae was found in 1 case after performing blood culture. Renal abscess was confirmed in all cases by doing contrast-enhanced CT scan, while only 9 cases with abscesses were identified by using renal ultrasound. There were 14 cases with renal abscess formation confirmed at onset by performing magnetic resonance imaging. Nine cases were accompanied with congenital anomalies of the kidney and urinary tract. All cases received conservative medical treatment. Intravenous broad-spectrum antibiotics were administered for 23 (14, 39) d initially, while the medication in 11 cases were upgraded to meropenem or imipenem. Oral antibiotics were continued for 23 (14, 28) d after discharge in all cases. Within 1 year of follow-up, except for 1 case of recurrence, the others had a favorable prognosis. Conclusions:Renal abscess should be suspected for children presenting with unexplained fever, vomiting, abdominal pain, elevated white blood cell count, C-reactive protein, erythrocyte sedimentation rate and pyuria. Ultrasonography is suitable for screening and follow-up, while CT or magnetic resonance imaging can be used to confirm the diagnosis. Conservative management with broad-spectrum antibiotics is effective and can be considered the first-line therapy for pediatric renal abscess.

Renal tubular acidosis（RTA）in children is mainly primary，with a low incidence rate and often an insidious onset. It exhibits strong clinical heterogeneity，and the related complications include growth retardation，abnormal bone metabolism，and renal dysfunction，which seriously affect the life quality of children. Currently，clinical attention to RTA remains insufficient，and its genetic mechanisms have not been fully clarified. The metabolic control rate and patient compliance need to be improved. This article reviews important research advances in the field of primary RTA，summarizes progress in classification，etiology，diagnostic and therapeutic strategies，prognosis and long-term disease management. It emphasizes that the precise diagnosis and treatment of children with primary RTA require the integration of molecular genetic technologies，individualized treatment regimens，and long-term monitoring and follow-up. In the future，efforts should focus on enhancing epidemiological studies and establishing evidence-based guidelines，further elucidating the pathogenesis of RTA，developing better-tolerated medications suitable for long-term use，and advancing parallel strategies for the prevention and management of primary RTA.

Objective:To evaluate the efficacy and safety of rituximab (RTX) in children with steroid resistant nephrotic syndrome (SRNS).Methods:The was a retrospective observational study. A retrospective analysis was conducted on the clinical data of 14 children with SRNS who received RTX treatment in the Department of Nephrology, Children's Hospital Affiliated to Capital Institute of Pediatrics from July 2021 to August 2023. The changes in urinary protein content, renal function, serum albumin, immunoglobulin and other indicators before and after RTX medication were compared to evaluate the clinical efficacy and safety of RTX treatment for SRNS.Results:A total of 14 children with SRNS were selected for this study, with a male to female ratio of 6:8. The age of onset of kidney disease was (4.36±3.12) years, and 8 of them underwent kidney biopsy. Among them, 6 cases showed focal segmental glomerulosclerosis in renal pathology, and 2 cases showed minimal change disease. The age of 14 children who first used RTX was (8.45±3.98) years old, with a dose of 375 mg/m 2 and a maximum dose of 500 mg. The number of children who had used 2, 3, 4, and 5 doses of RTX was 6, 6, 1, and 1, respectively. RTX was administered orally with compound sulfamethoxazole to prevent infection. Glucocorticoids and immunosuppressants were discontinued 4.0(2.5, 6.5) months after the first dose of RTX. The median follow-up time was 10.5(6.0, 18.3) months. By the end of the 3-month, 6-month, and follow-up endpoints, the complete remission rates of kidney disease in the children were 100.0%(14/14), 85.7%(12/14), and 64.3%(9/14), respectively. Five children experienced kidney disease recurrence. Compared with before the first dose of RTX treatment, the serum albumin and height significantly increased, while body mass index significantly decreased at the end of follow-up (all P<0.05). There was no statistically significant difference in urinary protein content, renal function, and IgG (all P>0.05). During the RTX treatment, all 14 children did not experience any infusion reaction, and there were no serious infections during follow-up. One case was diagnosed with hypogammaglobulinemia. Conclusions:RTX can improve the remission rate and recurrence rate of SRNS children, reduce the dosage of glucocorticoids and related drug untoward reaction, significantly improve patient height and BMI, with minimal side effects. Especially for SRNS patients who cannot be relieved by the combination of glucocorticoids and immunosuppressants, RTX may be considered.

Objective:To analyze the clinical characteristics of renal abscess in children and provide suggestions for early diagnosis and treatment.Methods:The clinical data including general information, laboratory data, imaging results, treatment and prognosis of 20 pediatric patients with renal abscess admitted to the Department of Nephrology, Capital Center for Children's Health Capital Medical University were analyzed retrospectively.Results:A total of 8 males and 12 females were enrolled. The age of onset was 3.0 (0.8, 9.0) years. All cases had fever. Six cases presented with abdominal pain, 6 cases had poor appetite, 5 cases had vomiting and 5 cases urinary tract irritation symptoms. Laboratory data showed elevated white blood cells 20.4 (17.4,26.3)×10 9/L, C-reactive protein 126 (77, 154)mg/L, erythrocyte sedimentation rate 60 (41,73) mm/1 h in 20 cases and procalcitonin 4.7 (1.2,33.5)μg/L in 10 cases. Totally 18 cases had pyuria. Urine culture was positive in 8 cases. Enterococcus faecium and Pseudomonas aeruginosa was detected in 2 cases. Klebsiella pneumoniae was found in 1 case after performing blood culture. Renal abscess was confirmed in all cases by doing contrast-enhanced CT scan, while only 9 cases with abscesses were identified by using renal ultrasound. There were 14 cases with renal abscess formation confirmed at onset by performing magnetic resonance imaging. Nine cases were accompanied with congenital anomalies of the kidney and urinary tract. All cases received conservative medical treatment. Intravenous broad-spectrum antibiotics were administered for 23 (14, 39) d initially, while the medication in 11 cases were upgraded to meropenem or imipenem. Oral antibiotics were continued for 23 (14, 28) d after discharge in all cases. Within 1 year of follow-up, except for 1 case of recurrence, the others had a favorable prognosis. Conclusions:Renal abscess should be suspected for children presenting with unexplained fever, vomiting, abdominal pain, elevated white blood cell count, C-reactive protein, erythrocyte sedimentation rate and pyuria. Ultrasonography is suitable for screening and follow-up, while CT or magnetic resonance imaging can be used to confirm the diagnosis. Conservative management with broad-spectrum antibiotics is effective and can be considered the first-line therapy for pediatric renal abscess.

Objective:To investigate the distribution and drug resistance of common pathogens causing urinary tract infection (UTI) in children in Beijing, so as to provide reference for clinical rational use of antibiotics.Methods:It was a retrospective cohort study. The results of clinical data, urine culture and drug sensitivity in children with urinary infection treated in the Department of Nephrology, Children's Hospital Affiliated to Capital Institute of Pediatrics from June 2018 to June 2018 were retrospectively analyzed. According to the diagnostic criteria of "Chinese expert consensus on the diagnosis and treatment of UTI (2015 edition) - Complicated urinary tract infection", the children were divided into complex group and simple group according to whether they had complicated factors, and the pathogenic factors of the complex group were analyzed. The χ 2 test was used to compare the distribution of pathogenic bacteria in urine culture and the resistance rate of Escherichia coli to common antibiotics between the two groups. Results:A total of 187 children with UTI were enrolled in this study. The age ranged from 1 month after birth to 17 years old, and the median age was 8 months. There were 88 males (47.1%) and 99 females (52.9%), and the male/female ratio was 1:1.125. Male infants accounted for 79.5% (70/88) of male infants and female infants accounted for 48.5% (48/99) of female infants. There were 45 cases (24.1%) in the simple UTI group and 142 cases (75.9%) in the complicated UTI group. A total of 216 strains of pathogens were isolated, mainly Gram-negative bacteria (151/216, 69.9%), of which Escherichia coli was the most common (86/216, 39.8%). The second was gram-positive bacteria (57/216, 26.4%), among which Enterococcus faecium (37/216, 17.1%) was the most common. The positive rate of Escherichia coli infection in the simple UTI group was significantly higher than that in the complicated UTI group [71.1% (32/45) vs. 31.6% (54/171), χ2=23.234, P<0.001], and the positive rate of Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecium and fungal infection in the simple UTI group was significantly lower than those in the complicated UTI group. However, the differences were not statistically significant (all P>0.05). The resistance rate of Escherichia coli to ampicillin was the highest in children with UTI [91.9% (79/86)], and it was sensitive to amikacin, meropenem, imipenem, piperacillin/tazobactam, cefepime, piperacillin, cefazolin, cefoperazone/sulbactam. The drug resistance rates were 5.8% (5/86), 5.8% (5/86), 9.3% (8/86), 10.5% (9/86), 14.0% (12/86), 15.1% (13/86), 18.6% (16/86) and 18.6% (16/86), respectively. The resistance rate of Escherichia coli infection to ceftriaxone in the complicated UTI group was significantly higher than that in the simple UTI group [59.3% (32/54) vs. 24.4% (11/32), χ2=4.977, P=0.026]. Eight fungi (3.7%) were susceptible to fluconazole, voriconazole, itraconazole and amphotericin B. Conclusions:The main pathogens of UTI in children are Gram-negative bacteria, among which Escherichia coli is the most common pathogen, but the proportion of infection has a downward trend in recent years. The resistance rate of ceftazidime and ceftriaxone is relatively low, which can be used as empirical drugs for children with UTI in this region.

Objective:To investigate the distribution and drug resistance of common pathogens causing urinary tract infection (UTI) in children in Beijing, so as to provide reference for clinical rational use of antibiotics.Methods:It was a retrospective cohort study. The results of clinical data, urine culture and drug sensitivity in children with urinary infection treated in the Department of Nephrology, Children's Hospital Affiliated to Capital Institute of Pediatrics from June 2018 to June 2018 were retrospectively analyzed. According to the diagnostic criteria of "Chinese expert consensus on the diagnosis and treatment of UTI (2015 edition) - Complicated urinary tract infection", the children were divided into complex group and simple group according to whether they had complicated factors, and the pathogenic factors of the complex group were analyzed. The χ 2 test was used to compare the distribution of pathogenic bacteria in urine culture and the resistance rate of Escherichia coli to common antibiotics between the two groups. Results:A total of 187 children with UTI were enrolled in this study. The age ranged from 1 month after birth to 17 years old, and the median age was 8 months. There were 88 males (47.1%) and 99 females (52.9%), and the male/female ratio was 1:1.125. Male infants accounted for 79.5% (70/88) of male infants and female infants accounted for 48.5% (48/99) of female infants. There were 45 cases (24.1%) in the simple UTI group and 142 cases (75.9%) in the complicated UTI group. A total of 216 strains of pathogens were isolated, mainly Gram-negative bacteria (151/216, 69.9%), of which Escherichia coli was the most common (86/216, 39.8%). The second was gram-positive bacteria (57/216, 26.4%), among which Enterococcus faecium (37/216, 17.1%) was the most common. The positive rate of Escherichia coli infection in the simple UTI group was significantly higher than that in the complicated UTI group [71.1% (32/45) vs. 31.6% (54/171), χ2=23.234, P<0.001], and the positive rate of Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecium and fungal infection in the simple UTI group was significantly lower than those in the complicated UTI group. However, the differences were not statistically significant (all P>0.05). The resistance rate of Escherichia coli to ampicillin was the highest in children with UTI [91.9% (79/86)], and it was sensitive to amikacin, meropenem, imipenem, piperacillin/tazobactam, cefepime, piperacillin, cefazolin, cefoperazone/sulbactam. The drug resistance rates were 5.8% (5/86), 5.8% (5/86), 9.3% (8/86), 10.5% (9/86), 14.0% (12/86), 15.1% (13/86), 18.6% (16/86) and 18.6% (16/86), respectively. The resistance rate of Escherichia coli infection to ceftriaxone in the complicated UTI group was significantly higher than that in the simple UTI group [59.3% (32/54) vs. 24.4% (11/32), χ2=4.977, P=0.026]. Eight fungi (3.7%) were susceptible to fluconazole, voriconazole, itraconazole and amphotericin B. Conclusions:The main pathogens of UTI in children are Gram-negative bacteria, among which Escherichia coli is the most common pathogen, but the proportion of infection has a downward trend in recent years. The resistance rate of ceftazidime and ceftriaxone is relatively low, which can be used as empirical drugs for children with UTI in this region.