This study aimed to investigate the clinical and molecular epidemiology and biofilm formation of Staphylococcus aureus (SA) isolated from pediatricians in China. SA strains were isolated from Beijing Children’s hospital from February 2016 to January 2017. Isolates were typed by multilocus sequence typing (MLST), spa and SCCmec typing (for Methicillin-resistant SA [MRSA] only). Antimicrobial susceptibility testing was performed by agar dilution method except sulphamethoxazole/trimethoprim (E-test method). Biofilm formation and biofilm associated genes were detected. Totally 104 children (41 females and 63 males; median age, 5.2 months) were enrolled in this study, in which 60 patients suffered from MRSA infection. Among the 104 cases, 54.8% were categorized as community associated SA (CA-SA) infections. The children under 3 years were more likely to occur CA-SA infections compared with older ones (P = 0.0131). ST59-SCCmec IV-t437 (61.7%) was the most prevalent genotype of MRSA, and ST22-t309 (18.2%), ST5-t002 (9.1%), ST6-t701 (9.1%), ST188-t189 (9.1%) were the top four genotypes of methicillin-sensitive SA (MSSA). All the present isolates were susceptible to linezolid, vancomycin, trimethoprim-sulfamethoxazole, mupirocin, tigecyclin, fusidic acid. No erythromycin-susceptible isolate was determined, and only a few isolates (3.8%) were identified as susceptible to penicillin. Multi-drug resistant isolates were reponsible for 83.8% of the ST59-SCCmec IV-t437 isolates. The isolates with strong biofilm formation were found in 85% of MRSA and 53.2% of MSSA, and in 88.7% of ST59-SCCmec IV-t437 isolates. Biofilm formation ability varied not only between MRSA and MSSA (P = 0.0053), but also greatly among different genotypes (P < 0.0001). The prevalence of the biofilm associated genes among ST59-SCCmec IV-t437 clone was: icaA (100.0%), icaD (97.3%), fnbpA (100.0%), fnbpB (0), clfA (100%), clfB (100%), cna (2.7%), bbp (0), ebpS (88.5%), sdrC (78.4%), sdrD (5.4%), and sdrE (94.5%). These results indicated strong homology of the MRSA stains isolated from Chinese children, which was caused by spread of multiresistant ST59-SCCmec IV-t437 clone with strong biofilm formation ability. The MSSA strains, in contrast, were very heterogeneity, half of which could produce biofilm strongly.

Respiratory syncytial virus (RSV) is the most common viral cause of pediatric bronchiolitis and pneumonia worldwide. Risk factors for high mortality and prolonged morbidity after RSV infection include premature birth, bronchopulmonary dysplasia, congenital heart disease, and Down syndrome. However, some previously healthy, full-term children who are infected with RSV also require hospitalization and even experience severe sequelae or death. In this report, we present the case of an RSV-associated death of a child who was born at full-term and developed normally up to the age of 2 years old. Cardiopulmonary arrest occurred within 3 days after the onset of symptoms, which included cough and high fever. Complete brain edema was prominent, and encephalopathy was developing. Viral antigen detection and microbiome analyses of oral swab and nasopharyngeal aspirate specimens verified an RSV infection, while bacterial culture of blood specimens yielded negative results. The RSV strain detected in this patient was subtyped as RSVB9, and no mutation was found in the six antigenic sites for targeted drugs or vaccines. The patient had a severe infection associated with RSV, which was very likely the cause of her central nervous system infection and acute neurological complications.

Linezolid is an oxazolidinone antibiotic exhibiting efficacy against multidrug-resistant (MDR) Gram-positive-related infections. However, its population pharmacokinetic (PopPK) profile in Chinese critically ill children has not been characterized. Optimal dosing regimens should be established according to the PopPK/pharmacodynamic(PD) properties of linezolid in the specific population. This work aims to describe the pharmacokinetic (PK) properties of linezolid, assess the factors affecting interpatient variability, and establish an optimized regimen for children in pediatric intensive care unit (PICU). A single-center, prospective, open-labeled PK study was performed. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was applied to measure the plasma levels during linezolid treatment. PopPK analysis was conducted using Phoenix NLME software. Sixty-three critically ill pediatric patients were included. The data showed good fit for a two-compartment model with linear elimination. Body weight and aspartate aminotransferase (AST) were the most significant covariates explaining variabilities in linezolid PK for the pediatric population. Therapeutic target was defined as the ratio of the area under drug plasma concentration-time curve over 24 h to minimum inhibitory concentration (AUC/MIC) of >80. Different dosing regimens were evaluated using Monte Carlo simulation to determine the optimal dosage strategy for linezolid. Although the probability of target attainment (PTA) was high (>96%) for 10 mg/kg every 8 h at MIC≤1 mg/L, it was lower than 70% at MIC>1 mg/L. Thus, the dosing regimen required adjustment. When the dosing regimen was adjusted to 15 mg/kg every 6 h, the PTA increased from 63.6% to 94.6% at MIC=2 mg/L, thereby indicating higher treatment success. Children with AST of >40 U/L had significant higher AUC than those with AST of ≤40 U/L (205.45 vs. 159.96). Therefore, dosage adjustment was required according to the AST levels. The PopPK characteristics of linezolid in critically ill children were evaluated, and an optimal dosage regimen was constructed based on developmental PopPK/PD model and simulation. (This study has been registered in the Chinese Clinical Trial Registry under no. ChiCTR1900021386.)

Importance: Acute necrotizing encephalopathy (ANE) is a rare disease with high mortality. Plasma exchange (PLEX) has recently been reported to treat ANE of childhood (ANEC), but its efficacy is uncertain.Objective: This study aimed to investigate the effectiveness of PLEX on ANEC.Methods: A retrospective study was conducted in four pediatric intensive care units from December 2014 to December 2020. All patients who were diagnosed with ANEC were included; however, these patients were excluded if their length of stay was less than 24 h. Participants were classified into PLEX and non‐PLEX groups.Results: Twenty‐nine patients with ANEC were identified, 10 in the PLEX group and 19 in the non‐PLEX group. In the PLEX group, C‐reactive protein, procalcitonin, alanine aminotransferase, and aspartate aminotransaminase levels were significantly lower after 3 days of treatment than before treatment (13.1 vs. 8.0, P = 0.043; 9.8 vs. 1.5, P = 0.028; 133.4 vs. 31.9, P = 0.028; 282.4 vs. 50.5, P = 0.046, respectively). Nine patients (31.0%, 9/29) died at discharge, and a significantly difference was found between the PLEX group and non‐PLEX group [0 vs. 47.4% (9/19), P = 0.011]. The median follow‐up period was 27 months, and three patients were lost to follow‐up. Thirteen patients (50.0%, 13/26) died at the last follow‐up, comprising three (33.3%, 3/9) in the PLEX group and ten (58.8%, 10/17) in the non‐PLEX group, but there was no significant difference between the two groups (P = 0.411). Three patients (10.3%, 3/29) fully recovered.Interpretation: PLEX may reduce serum C‐reactive protein and procalcitonin levels and improve liver function in the short term. PLEX may improve the prognosis of ANEC, and further studies are needed.