Limited protection of pneumococcal vaccines against emergent Streptococcus pneumoniae serotype 14/ST876 strains.

PURPOSE: Streptococcus pneumoniae (Spn) is a major cause of child death. We investigated the epidemiology of S. pneumoniae in a pediatric fever clinic and explored the genomics basis of the limited vaccine response of serotype 14 strains worldwide. METHODS: Febrile disease and pneumonia were diagnosed following criteria from the WHO at the end of 2019 at a tertiary children's hospital. Spn was isolated by culture from nasopharyngeal (NP) swabs. The density was determined by lytA-base qPCR. Isolates were serotyped by Quellung and underwent antimicrobial susceptibility testing. Whole-genome sequencing was employed for molecular serotyping, MLST, antibiotic gene determination, SNP calling, recombination prediction, and phylogenetic analysis. RESULTS: The presence of pneumococcus in the nasopharynx (87.5%, 7/8, p = 0.0227) and a high carriage (100%, 7/7, p = 0.0123) were significantly associated with pneumonia development. Living with siblings (73.7%, 14/19, p = 0.0125) and non-vaccination (56.0%, 28/50, p = 0.0377) contributed significantly to the Spn carriage. Serotype 14 was the most prevalent strain (16.67%, 5/30). The genome analysis of 1497 serotype 14 strains indicated S14/ST876 strains were only prevalent in China, presented limited vaccine responses with higher recombination activities within its cps locus, and unique variation patterns in the genes wzg and lrp. CONCLUSION: With the lifting of the one-child policy, it will be crucial for families with multiple children to get PCV vaccinations in China. Due to the highly variant cps locus and distinctive variation patterns in capsule shedding and binding proteins genes, the prevalent S14/ST876 strains have shown poor response to current vaccines. It is necessary to continue monitoring the molecular epidemiology of this vaccine escape clone.

Clinical characteristics of Kawasaki disease complicated with Mycoplasma pneumoniae pneumonia: A retrospective study.

This study aimed to investigate the inner linkage and mechanism of Mycoplasma pneumoniae (MP) infection and Kawasaki disease (KD), as well as the risk factors of outcome in this cohort of patients.A retrospective study was performed in 210 patients diagnosed with KD complicated with community acquired pneumonia (CAP) in Children's Hospital, Zhejiang University School of Medicine from January 2014 to December 2017. They were divided into two groups based on MP infection: MP infection group (n = 97) and non-MP infection group (n = 113). We compared the variables of these two groups based on medical records.The MP infection group had higher ESR than the non-MP infection group. During hospitalization, the non-MP infection group had higher levels of WBC during hospital, LDH, PCT, and lower HB when compared to the MP infection group. No differences were found in the hs-CRP level, N%, PLT, ALT, CKMB, and cytokine levels (IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ) between MP and non-MP infection group. Likewise, no difference was found in fever duration or hospital stays between them. Totally 19 patients in the infection group had CAA with a rate of 19.59%; and 27 (23.89%) patients had CAA in the non-MP infection group. Unfortunately, no difference was found in CAA rate between the two groups.MP infection may occur simultaneously in children with Kawasaki disease. KD patients with MP infection tended to occur in older population. MP infection may not increase the risk of CAA, which still needs further large-scaled studies to confirm. Clinicians should be alert to KD patients with high level of ESR. MP should be screened and early treatment with macrolides should be given timely.

[Effectiveness of methylprednisolone in treatment of children with refractory Mycoplasma pneumoniae pneumonia and its relationship with bronchoalveolar lavage cytokine levels].

OBJECTIVE: To investigate cytokine level in bronchoalveolar lavage fluid (BALF) in children with refractory Mycoplasma pneumoniae pneumonia (RMPP) and the effects of methylprednisolone on RMPP. METHOD: Sixty cases with RMPP and 20 cases with bronchial foreign body with no respiratory tract infection as control group hospitalized in Department of Pulmonary Diseases, the Children's Hospital Affiliated to Medical School of Zhejiang University from February 2012 to February 2013 were enrolled. The RMPP patients were divided into two groups randomly (30 cases in each). Steroid group were given methylprednisolone 2 mg/(kg·d) intravenously for 3 days, and the cases in non steroid group were not given steroid therapy. Patients whose fever relieved after steroid treatment were classified as defervesced group while the others were classified as non defervesced group. Each patient was examined with fiberoptic bronchoscopy and bronchoalveolar lavage 3 days after admission and cytokine level in BALF of each patient was detected. RESULT: (1) In steroid group, the proportion of patients whose fever disappeared within 3 days after steroid therapy was 9/30 cases (30%), and in non steroid group no one responded within 3 days after medication, showing statistically significant difference (χ² = 14.073, P=0.002), at the same time, the duration of cough in steroid group was significantly shorter than that in non steroid group (5.1 d vs. 7.0 d, t=-2.276, P=0.027). The total fever time of steroid group was 4.7 days, which as compaired with non steroid group (6.7 days) was shorter, but the difference was not significant (t=-1.351, P=0.134). (2) IL-1 ß, IL-4, IL-6, IL-8, IL-10, IFN-γ in BALF of steroid group and non steroid group were both significantly higher than that of control group. But the same comparison between steroid group and non steroid group showed no significant difference. (3) In steroid group, IL-2 and IL-8 in BALF of patient whose fever disappeared after steroid therapy were both significantly lower than that of patients who still had fever (t=2.771, 2.054, P=0.010, 0.049) , but no significant difference was found between the two groups in BALF IL-1 ß, IL-4, IL-6, IL-10, IFN-γ levels (P>0.05). CONCLUSION: (1) Three days of 2 mg/(kg·d) methylprednisolone therapy had the antipyretic effect in children with RMPP, and could shorten the length of cough. (2) Incresed BALF IL-1 ß, IL-4, IL-6, IL-8, IL-10, IFN-γ levels were observed in RMPP and high level of BALF IL-2 and IL-8 might have some relevance with persistent fever of RMPP in children.