Introduction This study aimed to understand the impact of the coronavirus disease 2019 (COVID-19) epidemic on the distribution and antibiotic resistance of pathogenic bacteria isolated from the lower respiratory tract of children in our hospital. Methods Antimicrobial susceptibility tests were performed on bacteria isolated clinically from the lower respiratory tracts of children in our hospital from 2018 to 2021 by the Kirby–Bauer method and automated systems. Results From 2018 to 2021, the top three lower respiratory tract clinical isolates in our hospital were Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae. These three species showed obvious seasonal epidemic patterns, and their numbers decreased significantly during the COVID-19 epidemic, from 4559 in 2019 to 1938 in 2020. Bacterial resistance to antibiotics also changed before and after the COVID-19 epidemic. The annual proportions of methicillin-resistant S. aureus (MRSA) were 41%, 37.4%, 26.2%, and 29.8%. The resistance rates of Klebsiella pneumoniae to ceftriaxone were 40.5%, 51.9%, 35.3%, and 53.3%, and the detection rates of carbapenem-resistant K. pneumoniae (CRKP) were 2.7%, 11.1%, 5.9%, and 4.4%. The detection rates of β-lactamase-producing H. influenzae were 51.9%, 59.2%, 48.9%, and 55.3%. The rate of MRSA, ceftriaxone-resistant K. pneumoniae, CRKP, and β-lactamase-producing H. influenzae decreased significantly in 2020 compared with 2019, whereas that of carbapenem-resistant P. aeruginosa and carbapenem-resistant A. baumannii increased. The detection rates of β-lactamase-negative ampicillin-resistant H. influenzae (BLNAR) gradually increased over the 4 years. Conclusions Protective measures against COVID-19, including reduced movement of people, hand hygiene, and surgical masks, may block the transmission of S. pneumoniae, H. influenzae, and M. catarrhalis and reduce the detection rate of MRSA, ceftriaxone-resistant K. pneumoniae, CRKP, and β-lactamase-producing H. influenzae.

Streptococcus pyogenes is a bacterial pathogen that causes a wide spectrum of clinical diseases exclusively in humans. The distribution of emm type, antibiotic resistance and virulence gene expression for S. pyogenes varies temporally and geographically, resulting in distinct disease spectra. In this study, we analyzed antibiotic resistance and resistance gene expression patterns among S. pyogenes isolates from pediatric patients in China and investigated the relationship between virulence gene expression, emm type, and disease categories. Forty-two representative emm1.0 and emm12.0 strains (n = 20 and n = 22, respectively) isolated from patients with scarlet fever or obstructive sleep apnea-hypopnea syndrome were subjected to whole-genome sequencing and phylogenetic analysis. These strains were further analyzed for susceptibility to vancomycin. We found a high rate and degree of resistance to macrolides and tetracycline in these strains, which mainly expressed ermB and tetM. The disease category correlated with emm type but not superantigens. The distribution of vanuG and virulence genes were associated with emm type. Previously reported important prophages, such as φHKU16.vir, φHKU488.vir, Φ5005.1, Φ5005.2, and Φ5005.3 encoding streptococcal toxin, and integrative conjugative elements (ICEs) such as ICE-emm12 and ICE-HKU397 encoding macrolide and tetracycline resistance were found present amongst emm1 or emm12 clones from Shenzhen, China.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune-mediated disease that affects patients with known genetic defects and is increasingly found among those with autoimmune diseases and persistent infections. Talaromyces marneffei (TM) is a human opportunistic fungus that commonly infects immunodeficient or immunosuppressed individuals. Few TM-associated secondary HLH cases resulting from autoimmune deficiency have been reported previously. The current case study describes a pediatric patient hospitalized with recurrent fever and lymphadenopathy. The child had abnormal blood cell classification, and microscopy revealed mature granulocytes that phagocytized fungal spores. It was speculated that the patient was infected with TM. The pathogen was detected earlier than the blood culture and confirmed by metagenomic next-generation sequencing. Whole-exome sequencing revealed that the patient had complex mutations associated with immunodeficiency. This included a mutation in exon 3 of the CD40LG gene, c.346G>A, which may be linked to hyper-IgM syndrome, a primary immunodeficiency disease with immunoglobulin conversion recombination defects that could explain the patient’s increased susceptibility to serious opportunistic infections. In addition, a heterozygous frameshift variant, c.820dup (p.Asp274GlyfsTer61), was detected in exon 6 of CARD9, a key gene associated with fungal immune surveillance. After 4 days of fungal treatment, the abnormal blood cell clusters disappeared, but other infections occurred in succession for 6 months after rehabilitation. The patient was followed with the aim of providing subsequent immunotherapy. This study found that infection can trigger HLH in HIV-negative individuals, highlighting the importance of early definitive identification of the causative agent and investigation of potential immunodeficiency.

Lipocalin-2 (LCN2) is a member of the lipocalin superfamily with multiple functions and can participate in the transport of a variety of small lipophilic ligands in vivo. LCN2 is significantly expressed in various tumors and ... | Find, read and cite all the research you need on Tech Science Press

Introduction: To determine the phenotypes and genotypes of invasive Streptococcus pneumoniae (S. pneumoniae), 108 strains were isolated from paediatric patients with invasive pneumococcal diseases (IPDs) in Shenzhen from 2014 to 2018. Methods: Serotype profiles were defined by multiplex PCR of the capsule gene. Pneumococcal surface protein A (PspA) classification was performed through pspA gene sequencing. Antimicrobial resistance was examined by broth microdilution. Multilocus sequence typing (MLST) was determined based on next-generation sequencing data. Results: Eighty-one S. pneumoniae of 17 serotypes were finally collected. The coverage of the 13-conjugated polysaccharide vaccine (PCV13) was 88.9%. After the introduction of PCV13, the nonvaccine serotypes were added by serotypes 15b, 16F and 20. Vaccine serotype 3 increased by four serious cases. The pspA family 1 and pspA family 2 are predominant. The multiple drug resistance rate is 91.3%. None of the nonmeningitis isolates were resistant to penicillin, while 98.8% of all the isolates were resistant to erythromycin. Discussion: This work characterizes the molecular epidemiology of invasive S. pneumoniae in Shenzhen. Continued surveillance of serotype distribution and antimicrobial susceptibility is necessary to alert antibiotic-resistant nonvaccine serotypes and highly virulent serotypes.

This retrospective study analyzed epidemiological features of infections by 13 common respiratory pathogens among children in Shenzhen, China, from January 2020 to February 2025. A total of 73,886 throat swabs from pediatric patients with suspected respiratory infections were tested using multiplex fluorescence PCR-capillary electrophoresis. Human rhinovirus (HRV), respiratory syncytial virus (RSV), Mycoplasma pneumoniae (MP), and human parainfluenza virus (HPIV) were the most prevalent, with positive rates of 24.57%, 12.46%, 11.46%, and 6.86%, respectively. Pathogen positivity rates significantly differed between the coronavirus disease 2019 (COVID-19) pandemic (2020–2022) and post-relaxation period (2023–2025) ( P < 0.0001). Seasonal patterns shifted: HPIV peaked in summer, HRV in autumn-winter, MP in summer-autumn, and RSV in spring. After control measures eased, positivity increased across all age groups. HPIV was highest in children aged 6 months to 1 year, HRV in 3–6 years, MP in >6 years, and RSV in 0–6 months. Age- and sex-related differences were significant (all P < 0.001). These findings indicate that evolving COVID-19 mitigation strategies have altered epidemiological patterns, highlighting the need for targeted prevention considering high-risk groups, co-infections, and seasonality. IMPORTANCE: This large-scale pediatric study reveals how coronavirus disease 2019 control measures and their relaxation reshaped respiratory pathogen epidemiology in Southern China. We identified major shifts in seasonal peaks, age-specific susceptibility, and overall infection prevalence, particularly for human rhinovirus, respiratory syncytial virus, Mycoplasma pneumoniae , and human parainfluenza virus. The narrowing or shifting of epidemic windows implies altered transmission dynamics, likely driven by nonpharmaceutical interventions and subsequent immunity gaps. The significant post-relaxation surge across all age groups underscores the vulnerability of children to multiple pathogens once restrictions ease. These findings provide crucial evidence for optimizing pediatric respiratory infection surveillance and designing adaptive, season- and age-specific prevention strategies to mitigate future outbreaks.