Background: Aseptic meningitis is most often caused by enteroviruses (EVs), but EVs associated with aseptic meningitis have not yet been reported in Liaocheng. The aim of this study was to determine the prevalence and genetic characteristics of EVs causing aseptic meningitis in children in Liaocheng.Methods: We reviewed the epidemiological and clinical characteristics of 504 paediatric cases of aseptic meningitis in Liaocheng from 2018 to 2019 and analysed the phylogeny of the predominant EV types causing this disease.Results: A total of 107 children were positive for EV in cerebrospinal fluid samples by nested PCR. Most of the positive patients were children 13 years old or younger and had symptoms such as fever, headache and vomiting (P < 0.05). The seasons with the highest prevalence of EV-positive cases were summer and autumn. The 107 EV sequences belonged to 8 serotypes, and echovirus types 18, 6 and 11 were the three dominant serotypes in Liaocheng during the 2-year study period. Phylogenetic analyses demonstrated that the E18 and E6 isolates belonged to subgenotype C2, while the E11 isolates belonged to subgenotype D5. VP1 analysis suggested that only one lineage of these three types was cocirculating in the Liaocheng region.Conclusions: This study demonstrated the diverse EV genotypes contributing to a large outbreak of aseptic meningitis in Liaocheng. Therefore, large-scale surveillance is required to assess the epidemiology of EVs associated with aseptic meningitis and is important for the diagnosis and treatment of aseptic meningitis in Liaocheng.

Background: Aseptic meningitis is the most common viral infection caused by human enteroviruses, but enteroviruses associated with aseptic meningitis in Liaocheng have not been reported yet. The aim of this study was to determine prevalence and genetic characteristics of enteroviruses causing aseptic meningitis in children in Liaocheng. Methods: We reviewed the epidemiological and clinical characteristics of 504 pediatric cases with aseptic meningitis in Liaocheng from 2018 to 2019, and analyzed the phylogeny of the predominant enterovirus (EV) types causing this disease. Results: A total of 107 children were positive for EV by the nested-PCR in cerebrospinal fluid samples. Most of the positive patients were children within 13 years old, had symptoms such as fever, headache and vomiting (P<0.05). The most prevalent seasons of EV-positive cases accurred in summer and autumn. The 107 EV sequences belonged to 8 serotypes, and echovirus types 18, 6 and 11 were the three dominant serotypes in Liaocheng during the 2-year period. Phylogentic analyses demonstrated that E18 and E6 isolates belonged to subgenotype C2, while E11 isolates belonged to subgenotype D5. The VP1 analysis suggested that only one lineage of these three types were co-circulating in Liaocheng region. Conclusions: This study demonstrated the diversified enterovirus genotypes attributing to the large outbreak of aseptic meningitis in Liaocheng. Therefore, the large-scale surveillance is required to the epidemiology of enteroviruses associated with aseptic meningitis, and is important for diagnosis and treatment of aseptic meningitis in Liaocheng.

Background: Mycoplasma pneumoniae (MP) is a leading cause of community-acquired pneumonia in children (CAP). Rising macrolide resistance and variability in clinical severity have become growing concerns. This study aimed to describe the molecular epidemiology, resistance patterns, and risk factors for severe M. pneumoniae pneumonia (SMPP) in children from Liaocheng, Shandong Province, China. Methods: We retrospectively enrolled 421 children hospitalized with MP pneumonia (MPP) between January 2023 and December 2024 in this study. Clinical and laboratory data were collected. M. pneumoniae -DNA-positive specimens were analyzed by 23S rRNA gene sequencing to identify macrolide resistance mutations, and by Multilocus Variable-Number Tandem Repeat Analysis (MLVA) for molecular typing. Univariate and multivariate logistic regression analyses were used to identify risk factors for SMPP. Results: Of the 421 patients, 212 (50.4%) were diagnosed with SMPP. Children with SMPP were significantly older than those with general MPP (GMPP) ( P = 0.001). Elevated D-dimer and lactate dehydrogenase (LDH) levels were identified as independent risk factors for SMPP. Among 148 successfully sequenced specimens, 144 (97.30%) carried macrolide resistance mutations, with A2063G being the most common (96.62%). MLVA typing identified 14 distinct subtypes, the most prevalent were M2-4-5-7-2, M5-4-5-7-2, M3-4-5-7-2, and M4-3-5-6-2. The subtype M4-3-5-6–2 was associated with a lower risk of SMPP (OR = 0.155, 95% CI: 0.037-0.654), while the subtype M3-4-5-7–2 carried the highest risk (OR = 14.0, P = 0.001). Conclusion: This study reveals a high rate of macrolide-resistant MP in Liaocheng, largely caused by the A2063G mutation. Elevated D-dimer and elevated LDH are independent predictors of SMPP. Certain MLVA subtypes are significantly associated with disease severity, suggesting they may help in risk assessment and clinical decision-making.