Background: Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen of community-acquired pneumonia in children. The factors contributing to the severity of illness caused by M. pneumoniae infection are still under investigation. We aimed to evaluate the sensitivity of common M. pneumoniae detection methods, as well as to analyze the clinical manifestations, genotypes, macrolide resistance, respiratory microenvironment, and their relationship with the severity of illness in children with M. pneumoniae pneumonia in Wuhan. Results: Among 1,259 clinical samples, 461 samples were positive for M. pneumoniae via quantitative polymerase chain reaction (qPCR). Furthermore, we found that while serological testing is not highly sensitive in detecting M. pneumoniae infection, but it may serve as an indicator for predicting severe cases. We successfully identified the adhesin P1 (P1) genotypes of 127 samples based on metagenomic and Sanger sequencing, with P1-type 1 (113/127, 88.98%) being the dominant genotype. No significant difference in pathogenicity was observed among different genotypes. The macrolide resistance rate of M. pneumoniae isolates was 96% (48/50) and all mutations were A2063G in domain V of 23S rRNA gene. There was no significant difference between the upper respiratory microbiome of patients with mild and severe symptoms. Conclusions: During the period of this study, the main circulating M. pneumoniae was P1-type 1, with a resistance rate of 96%. Key findings include the efficacy of qPCR in detecting M. pneumoniae, the potential of IgM titers exceeding 1:160 as indicators for illness severity, and the lack of a direct correlation between disease severity and genotypic characteristics or respiratory microenvironment. This study is the first to characterize the epidemic and genomic features of M. pneumoniae in Wuhan after the COVID-19 outbreak in 2020, which provides a scientific data basis for monitoring and infection prevention and control of M. pneumoniae in the post-pandemic era.

Porcine reproductive and respiratory syndrome (PRRS), caused by the PRRS virus (PRRSV), is considered one of the most devastating swine diseases worldwide. PRRSV-1 was first isolated in China in 2006. However, there were few reports concerning the genetic characteristics of PRRSV-1 in China. In this study, three PRRSV-1 strains (HL85, HeB3, and HeB47) were detected by a general RT-qPCR method from clinical samples in 2018. HeB47 was identified as a recombinant between the BJEU06-1 and CReSA228-like strains. To further analyze the recombination and deletion features of PRRSV-1, all the available 88 complete genome sequences (isolated in 19 countries) from 1991 to 2018 in GenBank were analyzed. The high-frequency recombination regions were concentrated in NSP2 and GP2 to GP4. More importantly, phylogenetic analysis of PRRSV-1 revealed four independent introductions in China. Therefore, it is necessary to strengthen the important monitoring of breeding pigs and pork products and epidemiological surveys on pig farms to prevent the further spread of PRRSV-1.

Porcine reproductive and respiratory syndrome virus (PRRSV) poses a serious threat to the pig industry in China. Our previous study demonstrated that PRRSV persists with local circulations and overseas imports in China and has formed a relatively stable epidemic pattern. However, the sudden African swine fever (ASF) outbreak in 2018 caused serious damage to China’s pig industry structure, which resulted in about 40 per cent of pigs being slaughtered. The pig yields recovered by the end of 2019. Thus, whether the ASF outbreak reframed PRRSV evolution with changes in pig populations and further posed new threats to the pig industry becomes a matter of concern. For this purpose, we conducted genomic surveillance and recombination, NSP2 polymorphism, population dynamics, and geographical spread analysis of PRRSV-2, which is dominant in China. The results showed that the prevalence of ASF had no significant effects on genetic diversities like lineage composition, recombination patterns, and NSP2 insertion and deletion patterns but was likely to lead to changes in PRRSV-2 recombination frequency. As for circulation of the two major sub-lineages of Lineage 1, there was no apparent transmission of NADC30-like among provinces, while NADC34-like had obvious signs of inter-provincial transmission and foreign importation during the ASF epidemic. In addition, two suspected vaccine recombinant epidemic strains suggest a slight safety issue of vaccine use. Herein, the interference of ASF to the PRRSV-2 evolutionary pattern was evaluated and vaccine safety was analyzed, in order to monitor the potential threat of PRRSV-2 to China’s pig industry in the post-epidemic era of ASF.

The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, poses a severe threat to humanity. Rapid and comprehensive analysis of both pathogen and host sequencing data is critical to track infection and inform therapies. In this study, we performed unbiased metatranscriptomic analysis of clinical samples from COVID-19 patients using a recently developed RNA-seq library construction method (TRACE-seq), which utilizes tagmentation activity of Tn5 on RNA/DNA hybrids. This approach avoids the laborious and time-consuming steps in traditional RNA-seq procedure, and hence is fast, sensitive, and convenient. We demonstrated that TRACE-seq allowed integrated characterization of full genome information of SARS-CoV-2, putative pathogens causing coinfection, antibiotic resistance, and host response from single throat swabs. We believe that the integrated information will deepen our understanding of pathogenesis and improve diagnostic accuracy for infectious diseases.

We aimed to investigate the continuous changes in respiratory virus epidemics in hospitalized children with lower respiratory tract infections (LRTIs) persisting from January 2019 to December 2022 in Wuhan, China. We retrospectively enrolled children with LRTIs admitted to the Wuhan Children's Hospital. Specimens were nasopharyngeal aspirates which had been collected and detected the following microorganisms with direct immunofluorescence: influenza virus types A and B, respiratory syncytial virus, parainfluenza virus types 1-3, and adenovirus. We also analyzed demographic data and laboratory test results. A total of 22,660 patients were enrolled. The total virus detection rate in 2019, 2021, and 2022 significantly declined gradually (36.96% vs 29.47% vs 22.62%, P value < 0.001). All the detected viruses did not follow previously observed seasonal patterns during the COVID-19 pandemic. Children hospitalized for LRTIs were older during the COVID-19 pandemic in contrast to the pre-period, particularly notable in cases attributed to respiratory syncytial virus and parainfluenza virus type 3 infections. This work adds to our knowledge of the epidemiology characteristics of respiratory viruses spanning the COVID-19 pandemic among children with LRTIs. The circulation of respiratory viruses changed consistently, and active LRTI surveillance in children remains critical for defining the healthcare burden of respiratory viruses.

16S rRNA gene sequencing is the gold standard for identifying microbial diversity in environmental communities. The Illumina short-read platform is widely used in marine environment studies due to its cost-effectiveness and high accuracy, but its limited read length restricts taxonomic identification mainly to genus or family levels. Recently, the PacBio long-read sequencing platform was developed. This method has exceptional base-level resolution exceeding 99%, thereby effectively mitigating the challenges associated with high error rates commonly observed in long-read sequencing technologies. However, few studies have compared the PacBio long-read and Illumina short-read platforms in marine deep-sea sediments. Here, the PacBio long-read and Illumina short-read platforms were compared with samples collected from the deep-sea surface sediments from the cold seep in the Shenhu area of the South China Sea offshore Pearl River Estuary. Comparisons revealed a more comprehensive taxonomic identification, α-diversity, and β-diversity by PacBio long-reads. The PacBio long-read platform exhibited higher classified rates and classified taxonomy at all levels, particularly at the species level. The PacBio long-read platform was also more accurate at capturing fine spatial-scale variations in microbial communities in sediments. Our studies will facilitate the selection of 16S rRNA sequencing platforms for investigating fine spatial-scale patterns in microbial communities in deep-sea surface sediments and serve as a crucial methodological reference for future studies on microbial diversity. IMPORTANCE: The PacBio long-read platform, with its exceptional base-level resolution exceeding 99%, has advanced our comprehension of deep-sea microbial diversity. By comparing microbial community analyses conducted using the Illumina short-read and PacBio long-read sequencing platforms, we have provided an enhanced understanding of fine spatial-scale patterns in microbial community diversity with depth across a deep-sea sediment core, as well as methodological insights that will be valuable for future research in this field.