A clade of Streptococcus pneumoniae clonal complex 320 with increased tolerance to ß-lactam antibiotics in a Chinese metropolitan city.

OBJECTIVES: We characterized the population structure and features of clinical Streptococcus pneumoniae isolates associated with invasive pneumococcal disease (IPD) from 2009 to 2017 in a Chinese metropolitan city using a whole-genome sequencing approach. METHODS: Seventy-nine pneumococcal strains, including 60 serogroup-19 strains from children enduring IPD from a paediatric hospital in Shenzhen, were subjected to whole-genome sequencing. Population structure was characterized through phylogenetic analysis, sequence typing, serotyping, virulence factor, and antimicrobial drug resistance (AMR) gene profiling, combining the publicly available related WGS data. Clinical demography and antibiotic susceptibility profiles were compared among different populations to emphasize the higher-risk populations. Genetic regions associated with AMR gene mobilization were identified through comparative genomics. RESULTS: These IPD strains mainly belonged to clonal complex 320 (CC320) and were composed of serotypes 19A and 19F. In addition to sporadic possible importation-related isolates (ST320), we identified an independent clade, CC320_SZpop (ST271), that predominantly circulated in Shenzhen and possibly expanded its range. Clinical features and antibiotic susceptibility analysis revealed that CC320_SZpop might manifest much higher pathogenicity and tolerance to ß-lactams. Specific virulence factors in Shenzhen isolates of CC320_SZpop were identified. Furthermore, an ca. 40 kb hotspot genomic region enduring frequent recombination was identified, possibly associated with the divergence of S. pneumoniae strains. CONCLUSION: A novel pneumococcal clade, CC320_SZpop, circulating in Shenzhen and other regions in China, possibly under expansion, was found and deserves more study and surveillance. Our study also emphasizes the importance of continuous genomic surveillance of clinical S. pneumoniae isolates, especially IPD isolates.

Molecular characteristics and antimicrobial resistance of invasive pneumococcal isolates from children in the post-13-valent pneumococcal conjugate vaccine era in Shenzhen, China.

OBJECTIVES: This study aimed to evaluate the molecular epidemiology and antimicrobial resistance of invasive pneumococcal isolates from children in Shenzhen, China, in the early stage of the pneumococcal 13-valent conjugated vaccine (PCV-13) era from 2018 to 2020. METHODS: Invasive pneumococcal strains were isolated from hospitalized children with invasive pneumococcal diseases (IPDs) from January 2018 to December 2020. The serotype identification, multilocus sequence typing (MLST), and antibiotic susceptibility tests were performed on all culture-confirmed strains. RESULTS: Sixty-four invasive strains were isolated mainly from blood (70.3%). Prevalent serotypes were 23F (28.1%), 14 (18.8%), 19F (15.6%), 6A/B (14.1%), and 19A (12.5%), with a serotype coverage rate of 96.9% for PCV13. The most common sequence types (STs) were ST876 (17.1%), ST271 (10.9%), and ST320 (7.8%). Half of the strains were grouped in clonal complexes (CCs): CC271 (21.9%), CC876 (20.3%), and CC90 (14.1%). Meningitis isolates showed a higher resistance rate (90.9% and 45.5%) to penicillin and ceftriaxone than the rate (3.8% and 9.4%) of non-meningitis isolates. The resistance rates for penicillin (oral), cefuroxime, and erythromycin were 53.13%, 73.4%, and 96.9%, respectively. The dual ermB and mefA genotype was found in 81.3% of erythromycin-resistant strains. The elevated minimum inhibitory concentration (MIC) of ß-lactam antibiotics and dual-genotype macrolide resistance were related mainly to three major serotype-CC combinations: 19F-CC271, 19A-CC271, and 14-CC876. CONCLUSION: Invasive pneumococcus with elevated MICs of ß-lactams and increased dual ermB and mefA genotype macrolide resistance were alarming. Expanded PCV13 vaccination is expected to reduce the burden of paediatric IPD and to combat antibiotic-resistant pneumococcus in Shenzhen.

Risk factors for death associated with severe influenza in children and the impact of the COVID-19 pandemic on clinical characteristics.

Background: To summarize the clinical features of severe influenza in children and the high-risk factors for influenza-related deaths and to raise awareness among pediatricians. Methods: A retrospective study of clinical manifestations, laboratory tests, and diagnosis and treatment of 243 children with severe influenza admitted to Shenzhen Children's Hospital from January 2009 to December 2022 was conducted. Univariate logistic regression analysis and Boruta analysis were also performed to identify potentially critical clinical characteristics associated with death, and clinically significant were used in further multivariate logistic regression analysis. Subject receiver operating characteristic (ROC) curves were applied to assess the efficacy of death-related independent risk factors to predict death from severe influenza. Results: There were 169 male and 74 female patients with severe influenza, with a median age of 3 years and 2 months and 77.4% of patients under six. There were 46 cases (18.9%) in the death group. The most common pathogen was Influenza A virus (IAV) (81.5%). The most common complication in the death group was influenza-associated acute necrotizing encephalopathy (ANE [52.2%]). Severe influenza in children decreased significantly during the COVID-19 pandemic, with a median age of 5 years, a high predominance of neurological symptoms such as ANE (P = 0.001), and the most common pathogen being H3N2 (P < 0.001). D-dimer, acute respiratory distress syndrome (ARDS), and acute necrotizing encephalopathy (ANE) were significant independent risk factors for severe influenza-associated death. Furthermore, the ROC curves showed that the combined diagnosis of independent risk factors had significant early diagnostic value for severe influenza-related deaths. Conclusion: Neurological disorders such as ANE are more significant in children with severe influenza after the COVID-19 pandemic. Influenza virus infection can cause serious multisystem complications such as ARDS and ANE, and D-dimer has predictive value for early diagnosis and determination of the prognosis of children with severe influenza.

[Clinical features of influenza with plastic bronchitis in children].

OBJECTIVE: To study the clinical features of influenza with plastic bronchitis (PB) in children, and to improve the awareness of the diagnosis and treatment of PB caused by influenza virus. METHODS: A retrospective analysis was performed for the clinical data of 70 children with lower respiratory influenza virus infection from October 2018 to October 2019. According to the presence or absence of PB, they were divided into an influenza+PB group with 12 children and a non-PB influenza group with 58 children. Related clinical data were collected for the retrospective analysis, including general information, clinical manifestations, laboratory examination, imaging findings, treatment, and prognosis. RESULTS: In the influenza+PB group, most children experienced disease onset at the age of 1-5 years, with the peak months of January, February, July, and September. Major clinical manifestations in the influenza+PB group included fever, cough, and shortness of breath. The influenza+PB group had significantly higher incidence rates of shortness of breath and allergic diseases such as asthma than the non-PB influenza group (P<0.05). Of the 12 children in the influenza+PB group, 7(58%) had influenza A virus infection and 5 (42%) had influenza B virus infection, among whom 1 had nephrotic syndrome. For the children in the influenza+PB group, major imaging findings included pulmonary consolidation with atelectasis, high-density infiltration, pleural effusion, and mediastinal emphysema. Compared with the non-PB influenza group, the influenza+PB group had a significantly higher proportion of children who were admitted to the pediatric intensive care unit (P<0.05). Bronchoscopic lavage was performed within 1 week after admission, and all children were improved and discharged after anti-infective therapy and symptomatic/supportive treatment. CONCLUSIONS: Influenza with PB tends to have acute onset and rapid progression, and it is important to perform bronchoscopy as early as possible. The possibility of PB should be considered when the presence of shortness of breath, allergic diseases such as asthma or nephrotic syndrome in children with influenza.