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Discovery of Respiratory Pathogens in People Living With HIV in the African Cohort Study.

INTRODUCTION: Respiratory infection outbreaks pose a threat to the readiness of the United States and allied armed forces. Predicting and preventing such outbreaks requires understanding of the epidemiology of potential respiratory pathogens in communities where service members live and work. We conducted pan-viral surveillance of respiratory specimens from people living with HIV or without HIV but under the risk enrolled in the U.S. Military HIV Research Program's African Cohort Study to determine the prevalence and possible clinical presentation of viruses in this population. METHODS: The African Cohort Study is an open-ended prospective cohort study that enrolls people with and without HIV aged ≥15 years at 12 clinical sites in Kenya, Tanzania, Uganda, and Nigeria. The study follows participants every 6 months and collects social, demographic, clinical, and laboratory data. A total of 131 respiratory samples, collected from March 2022 to February 2023 from participants in South Rift Valley Province, Kenya, who had symptoms of respiratory illness or a positive COVID-19 test, were analyzed using a pan-viral hybridization metagenomic next-generation sequencing approach. Libraries were sequenced on the Illumina Next-generation Sequencing System NovaSeq 6000. Sample data were run through several pathogen discovery pipelines. RESULTS: Full genome and partial genome sequences were assembled for several respiratory viruses including SARS-CoV-2, human coronavirus HKU1, human adenovirus 62, human metapneumovirus, human mastadenovirus B (coinfection with SARS-CoV-2), human mastadenovirus C (coinfection with SARS-CoV-2), and human parechovirus 3 (coinfection with adenovirus 62). The results showed that SARS-CoV-2 lineages correspond with lineages circulating during March 2022 to February 2023 and revealed additional viral respiratory pathogens and viruses known to be associated with HIV. CONCLUSIONS: These preliminary results suggest that continued genomic surveillance efforts are needed for data-driven decisions on force health protection, prevention of emerging respiratory infections, and mitigation of impacts on military readiness caused by infectious diseases.

Humans

Public Health Indoor Air Surveillance for Respiratory Pathogens: From Pilot to Citywide Implementation.

CONTEXT: Environmental surveillance has become an essential component of public health pathogen surveillance programs. Indoor air surveillance is a promising environmental surveillance method but has yet to be scaled citywide and incorporated into state and local public health programs. PROGRAM: The Chicago Department of Public Health established a citywide indoor air surveillance program to enhance monitoring of airborne pathogens and address gaps in existing surveillance. IMPLEMENTATION: The program began with a pilot phase from February to April 2023 at 5 sites, which informed expansion to 17 sites and 20 samplers across emergency departments (5), congregate (3), and community settings (15), across the city. Site staff conducted weekly cartridge exchanges for seven-day sample collection periods using AerosolSense and AirPrep Cub samplers, which were then processed at the Regional Innovative Public Health Laboratory for SARS-CoV-2, influenza, and respiratory syncytial virus. Samples were tested using quantitative polymerase chain reaction, and SARS-CoV-2-positive samples underwent whole genome sequencing to characterize circulating viral lineages. EVALUATION: From February 2023 to August 2025, 1246 samples were processed, with a mean compliance of 85% (SD = 0.149) for weekly cartridge exchanges and minimal operational disruption. The program data supported its use as a surveillance tool for respiratory pathogen detection and SARS-CoV-2 lineage monitoring, with 74% samples positive for at least 1 virus and 68% detecting SARS-CoV-2. DISCUSSION: The program successfully scaled to citywide coverage and was shown to be feasible and acceptable across sites. These results highlight the value of indoor air monitoring as a complementary surveillance tool and offer a framework for other jurisdictions seeking to enhance respiratory pathogen detection through establishing a citywide indoor air surveillance program. Facility-level sampling is aggregated across sites to capture citywide trends complementing clinical and wastewater surveillance, and provides insights into facility-level pathogen burden, not captured by other surveillance methods.

Humans

Oral cavity as a reservoir of respiratory pathogens: microbial dynamics in patients receiving mechanical ventilation.

OBJECTIVE: To investigate the prevalence, co-occurrence, and temporal dynamics of Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae, and Pseudomonas aeruginosa in oral and tracheal samples from critically ill patients receiving mechanical ventilation. METHODS: This observational analytical study included 21 adult patients receiving mechanical ventilation who were admitted to an intensive care unit. Oral and tracheal samples were collected within the first 24 h after intubation (Day 0) and again after 48 h (Day 2). Bacterial genomic deoxyribonucleic acid was extracted and analyzed using quantitative realtime polymerase chain reaction. Microbial detection was evaluated qualitatively based on the presence or absence of each microorganism and quantitatively using relative bacterial load analysis. Statistical analyses assessed correlations between oral and tracheal colonization patterns and temporal changes in bacterial load. RESULTS: More than 43% of oral and tracheal samples tested positive for at least one investigated pathogen at both collection time points, indicating persistent microbial colonization during mechanical ventilation. Significant positive correlations for Staphylococcus aureus detection were observed between oral and tracheal samples on Day 0 (p=0.0028) and Day 2 (p=0.0021), suggesting a possible association between oral colonization and lower airway microbial presence. Streptococcus pneumoniae detected in initial oral samples showed a significant correlation with tracheal detection after 48 h (p=0.03). Quantitative analyses demonstrated no significant changes in bacterial load over time for most microorganisms. However, Klebsiella pneumoniae showed a significant increase in tracheal bacterial load between Day 0 and Day 2 (p=0.04), with higher tracheal loads than oral samples on Day 2 (p=0.01). CONCLUSION: The oral cavity may serve as an important reservoir of respiratory pathogens in patients receiving mechanical ventilation. The observed correlations between oral and tracheal colonization and pathogen-specific colonization patterns reinforce the relevance of oral health management in critical care settings. In particular, the increase in tracheal Klebsiella pneumoniae load suggests that lower airway proliferation may occur during mechanical ventilation independently of simultaneous increases in oral bacterial load.

Humans

Multimodal genomic surveillance for respiratory pathogens at four U.S. international airports: A comparison of air, wastewater, clinical, and national surveillance data.

Early detection of outbreaks and emerging pathogens is critical for public health and global biosecurity. Airports, as major international travel hubs with dense, enclosed populations, are high-risk settings for disease transmission and potential pathogen introduction. The U.S. Centers for Disease Control and Prevention, in collaboration with Ginkgo Biosecurity and the University of Wisconsin-Madison, implemented air monitoring for pathogen surveillance in congregate areas at four U.S. international airports. From October 2023 to August 2024, SARS-CoV-2 was detected by PCR in 98.3% of air samples and influenza A in 17.2%. Influenza A positivity in air samples correlated with aviation wastewater (r = 0.48), traveler nasal swab positivity (r = 0.73), and national clinical surveillance (r = 0.86), whereas SARS-CoV-2 measurements did not correlate significantly across these modalities. Targeted amplicon sequencing of SARS-CoV-2 from air samples identified contemporaneous lineages also detected in wastewater collected from the same airports. Targeted enrichment sequencing detected 30 viral species and recovered high-quality genomes for SARS-CoV-2, influenza, bocavirus, and seasonal coronaviruses. Together, these findings demonstrate that air sampling can complement aviation wastewater surveillance at ports of entry, although performance and concordance vary by pathogen and sample type.

Journal Article

Genomic surveillance of enterovirus D68 circulating in 2025 reveals the emergence of a novel A2/B3 recombinant lineage.

Enterovirus D68 (EV-D68) has re-emerged over the past decade as a significant respiratory pathogen associated with severe respiratory disease and acute flaccid myelitis. Its circulation has typically followed a biennial pattern, with predominance in late summer and early fall, a pattern that was temporarily disrupted during the COVID-19 pandemic. Surveillance in 2025 revealed off-season circulation of EV-D68. This study describes the genomic characteristics of the 2025 EV-D68 viruses and the clinical features of affected patients. Between May and December 2025, remnant respiratory specimens positive for rhinovirus/enterovirus were screened for EV-D68 and subjected to whole-genome sequencing. Phylogenetic analyses were performed using maximum-likelihood methods. Recombination was assessed using subgenomic phylogenies, SimPlot similarity and BootScan analyses, and read-level inspection. Among 1,321 patients tested, 147 (11.1%) were EV-D68-positive, and 119 (81.0%) yielded complete genomes. EV-D68 positivity increased in July 2025, peaked in August (~21%), and remained elevated through September and October, exceeding levels observed in 2024. Patients had a median age of 36 years, with infections disproportionately affecting older adults. Phylogenetic analysis demonstrated exclusive circulation of subclade A2. Five genomes formed a distinct recombinant lineage (A2-Re). Subgenomic phylogenies showed clustering with A2 viruses in the P1 region and with B3 viruses in the P2-P3 regions. SimPlot and BootScan analyses identified a recombination breakpoint near the 2A/2B junction (~nt 3,700). The recombinant lineage was associated with temporally clustered cases in September-October. These findings demonstrate recombination between distinct EV-D68 subclades and underscore the importance of whole-genome surveillance for accurate viral characterization. Continued genomic monitoring is essential for detecting emerging variants with potential implications for transmissibility, pathogenicity, and public health preparedness.IMPORTANCEThis study highlights an increased off-season circulation of Enterovirus D68 (EV-D68) and a higher burden of disease in adults in 2025. The identification of a novel A2-B3 recombinant lineage provides evidence of ongoing viral evolution through recombination, a mechanism that may alter transmissibility, virulence, or immune responses. Detection of this lineage in temporally clustered cases suggests local transmission and underscores the potential for rapid spread of newly emerged variants. These findings emphasize the limitations of partial genomic approaches and the critical role of whole-genome sequencing in accurately characterizing circulating strains and identifying recombination events. Enhanced genomic surveillance is essential to detect emerging variants in real time, inform diagnostic assay performance, and support public health responses. Continued monitoring of EV-D68 evolution will be important for anticipating changes in disease burden, guiding clinical awareness, and strengthening preparedness for future outbreaks.

Humans

Application of metagenomic next-generation sequencing in children with pneumonia of unknown etiology.

OBJECTIVE: To investigate the pathogen spectrum and clinical application value of metagenomic next-generation sequencing (mNGS) in lower respiratory tract specimens from children with pneumonia of unknown etiology. METHODS: A retrospective analysis was conducted on children hospitalized in the intensive care unit (ICU) and respiratory department ward of Children's Hospital of Chongqing Medical University from January 2025 to December 2025. All enrolled cases presented negative results for conventional respiratory pathogen tests and received mNGS testing of lower respiratory tract specimens for etiological identification. The mNGS findings and clinical data of the included children were analyzed. RESULTS: A total of 92 children were enrolled, including 54 males and 38 females, with ages ranging from 2 months to 13 years and 8 months. Causative pathogens were detected in 77 cases (83.7%). The clinically adjudicated etiological diagnosis rates of bacteria, viruses, fungi and atypical pathogens were 75.0% (69/92), 37.0% (34/92), 13.0% (12/92) and 5.4% (5/92), respectively. Thirty-eight cases were complicated with polymicrobial infection, among which bacterial-viral infection was predominant, accounting for 23.1% (24/92). Children with immunocompromised conditions exhibited higher incidences of clinically adjudicated bacterial, fungal and polymicrobial infection than immunocompetent patients. The most common clinically confirmed causative pathogens in immunocompromised children were Streptococcus pneumoniae, human cytomegalovirus, Haemophilus influenzae, Stenotrophomonas maltophilia and Enterococcus faecalis. Treatment regimens were adjusted in 58 cases (63.0%) based on mNGS findings, switching to pathogen-targeted anti-infective therapy. CONCLUSION: For pediatric pneumonia with negative conventional etiological tests, mNGS of lower respiratory tract specimens significantly enhances pathogen detection rates, effectively identifies polymicrobial infection and opportunistic pathogens. Immune status serves as a critical stratification factor influencing pathogen spectrum and infection patterns, with immunocompromised children being more susceptible to opportunistic infections. Adjustment of anti-infective regimens based on mNGS results can effectively facilitate personalized anti-infective therapy.

Humans

Distinct Evolutionary Signatures of Human Parainfluenza Viruses 2 and 4 Reveal Host Antagonism Divergence and Phylogenetic Discordance.

Human parainfluenza virus 2 (HPIV-2) and human parainfluenza virus 4 (HPIV-4) are significant but underappreciated respiratory pathogens, particularly among high-risk populations including children, the elderly, and immunocompromised individuals. In this study, we sequenced 101 HPIV-2 and HPIV-4 genomes from respiratory samples collected in western Washington State and performed comprehensive evolutionary analyses using both new and publicly available sequences. Phylogenetic and phylodynamic analyses revealed that both HPIV-2 and HPIV-4 evolve at significantly faster rates compared to the mumps virus, a reference human orthorubulavirus. Notably, while HPIV-2 demonstrated the highest evolutionary rates in the surface glycoprotein HN, consistent with humoral immune-driven selection, the innate immune antagonist V/P gene evolved fastest in HPIV-4. We identified a hypervariable region within the HPIV-4V/P protein (residues 35 to 75), which structural modeling placed in a loop overlapping a known interferon antagonism domain in other paramyxovirus V proteins, though HPIV-4 is functionally incompetent in this activity. Expanded phylogenetic analysis across the Paramyxoviridae family uncovered a striking evolutionary discordance: while the HN glycoprotein and L polymerase of HPIV-4 and its 2 closest bat-derived viruses clustered within the Orthorubulavirus genus, their nucleoprotein (N), phosphoprotein (P), matrix (M), and fusion (F) proteins formed a distinct lineage outside the Rubulavirinae subfamily. Together, these findings highlight the distinct evolutionary trajectories of HPIV-2 and HPIV-4, raise hypotheses around complex Paramyxoviridae zoonotic events including recombination-like patterns, and demonstrate limitations of current L protein-based taxonomic classification schemes.

Humans

Acute respiratory viral diseases in Amazonas, Brazil: epidemiological patterns and implications for health surveillance.

BACKGROUND: Acute respiratory viral diseases are a major public health challenge in the Brazilian Amazon, where ecological, logistical, and social factors shape patterns of transmission and response. METHODS: This study aimed to analyze the epidemiological patterns and temporal-spatial distribution of Influenza-like illness (ILI) and severe acute respiratory syndrome (SARS) in the state of Amazonas, Brazil, between 2015 and 2025, distinguishing SARS-CoV-2 and non-SARS-CoV-2 etiologies using data from OpenDataSUS. RESULTS: Incidence peaks occurred in early 2021 and 2022, with pronounced regional disparities. The highest burdens were concentrated in specific municipalities, with Manaus exhibiting an intermediate incidence and playing a central role in case notifications and healthcare provision. DISCUSSION: We describe the integration of surveillance systems, laboratory networks, and healthcare infrastructure, which enabled improvements in diagnosis, monitoring, and care. The region's response model, centered in Manaus, includes primary-to-tertiary care coordination, molecular diagnostics, telemedicine, and mobile health units for Indigenous and remote areas. Research efforts during the COVID-19 pandemic provided critical insights into therapeutic strategies, immunopathology, and long-term sequelae, while also highlighting persistent inequities and diagnostic gaps. Our findings underscore the co-circulation of multiple respiratory pathogens and the need for continued genomic and syndromic surveillance. Future strategies must address regional disparities, support decentralized diagnostics, and expand clinical research. Strengthening integrated health systems in the Brazilian Amazon is essential for timely, equitable responses to emerging respiratory threats.

Brazil

Influenza A virus in Swiss pig herds with respiratory disease: Seasonality and age dependence.

Influenza A virus (IAV) is an important respiratory pathogen in pigs and poses a zoonotic risk to humans in close contact. While IAV epidemiology has been extensively studied in large-scale production systems, data from Switzerland - characterized by small herds and limited live pig imports - remain scarce. This exploratory nationwide cross-sectional study aimed to assess the association between herd-level IAV detection and reported respiratory disease in pig herds, and to explore associations with husbandry-, animal-, and human health-related factors. Between November 2023 and April 2025, 25 Swiss pig herds with caretaker-suspected respiratory symptoms were investigated. In each herd, five nasal swabs were collected and analyzed by quantitative PCR. Herd managers completed an interview, and clinical examinations were performed. Overall, 56 % (95 % CI: 37,1 - 73,3) of herds tested positive for IAV, comparable to reports from other European countries. The estimated intra-herd detection rate was 49,6 % (95 % CI: 31,2 - 68,0). Respiratory disease outbreaks associated with IAV detection showed indications of seasonal variation, with no positive herds identified during summer. Across age groups, pigs aged 11-14 weeks had a higher likelihood of IAV detection, with 15,79-fold increased odds (95 % CI: 1,50 - 860,4), although with considerable uncertainty. The interpretation is limited by the small sample size, heterogeneous data, and reliance on single time-point qPCR detection. The results suggest that IAV detection in clinically apparent respiratory outbreaks may follow seasonal patterns in Swiss pig herds. Weaners and newly introduced fattening pigs may play a role in such respiratory outbreaks and could represent relevant targets for IAV surveillance in Switzerland. Continued monitoring and the implemen tation of appropriate control measures remain important given the virus's zoonotic potential and impact on pig health.

Animals

[Genomic evolution and epidemiological patterns of respiratory syncytial virus and their implications for surveillance and early warning].

Respiratory syncytial virus (RSV) is an important respiratory pathogen in infants, young children and older adults. Based on global RSV genomic surveillance data, this review systematically summarizes the geographic distribution, seasonal epidemic patterns, and long-term evolutionary trends of RSV, with particular emphasis on the sustained circulation and evolutionary mechanisms of dominant genotypes such as ON1 in RSV-A and BA9 in RSV-B. Current evidence indicates that RSV transmission dynamics are tightly coupled with viral evolution. The G gene evolves relatively rapidly and contains multiple positively selected sites, suggesting an important role in immune escape and population adaptation. In recent years, changes in social behavior patterns and population immunity have further disrupted the seasonal rhythm of RSV and may have influenced the spread of dominant genotypes. Under routine respiratory infectious disease surveillance, strengthened genomic monitoring and integration of multi-source data are needed to improve early warning of abnormal RSV epidemics and variant-associated risks, thereby providing prospective evidence for protecting high-risk populations and informing public health decision-making.

Humans

A standardized, genome-guided MLST scheme for Avibacterium paragallinarum: enhanced epidemiological typing and validation against existing methods.

Avibacterium paragallinarum, the causative agent of infectious coryza (IC), is an important respiratory pathogen of chickens with growing prevalence in commercial and backyard flocks. Current strain-typing methods, including classical serotyping and molecular approaches, such as ERIC-PCR or single-locus HPG2 typing, lack sufficient discriminatory power to investigate the epidemiology or population structure. To address this limitation, we developed a genome-guided multilocus sequence typing (MLST) scheme as a robust and portable tool for A. paragallinarum strain differentiation. Housekeeping genes were identified from 42 whole-genome sequences (WGS); 18 candidates were evaluated; and six were selected for the final MLST scheme. We used the scheme to differentiate 75 A. paragallinarum samples and compared its performance against classical HPG2-based typing, ad hoc core genome MLST (cgMLST), and the MLST scheme published by M. Guo, Y. Jin, H. Wang, X. Zhang, and Y. Wu (Vet Sci 11:208, 2024, https://doi.org/10.3390/vetsci11050208). The new MLST showed higher discriminatory power than HPG2 and outperformed Guo's scheme with higher discriminatory power, particularly for characterizing the samples originating from North and South America. It also showed strong concordance with cgMLST clustering while being more practical for routine use. Overall, the six-locus MLST identified 31 sequence types across 75 samples, revealing epidemiologically meaningful clustering at regional and national scales and capturing temporal persistence of lineages. All allele definitions and sequence types have been deposited in PubMLST, ensuring standardized nomenclature and global accessibility. This scheme represents a reproducible, cost-effective, and globally applicable tool that enhances outbreak investigation, surveillance, and population studies of A. paragallinarum, bridging the gap between low-resolution traditional methods and resource-intensive whole-genome sequencing.IMPORTANCEInfectious coryza (IC) caused by Avibacterium paragallinarum is a major respiratory disease of poultry that causes acute infection, reducing egg production and growth and resulting in significant economic losses in poultry production worldwide. Controlling IC depends on understanding how different strains spread and persist, yet current methods to differentiate strains are either unreliable or too costly for routine use. In this study, we developed a standardized multilocus sequence typing system that provides a simple, accurate, and globally accessible way to identify and compare strains of A. paragallinarum. This scheme identified important links between outbreaks at local and regional levels and showed that certain strains persisted over time. By making the scheme available through PubMLST, laboratories worldwide can use a common tool to track and investigate the pathogen. This accessible tool improves disease surveillance, supports outbreak investigations, and helps poultry producers and veterinarians respond more effectively to IC.

Multilocus Sequence Typing

Human parainfluenza virus 3 vaccine candidates attenuated by codon-pair deoptimization are immunogenic and protective in hamsters.

Human parainfluenza virus type 3 (HPIV3) is a major pediatric respiratory pathogen lacking available vaccines or antiviral drugs. We generated live-attenuated HPIV3 vaccine candidates by codon-pair deoptimization (CPD). HPIV3 open reading frames (ORFs) encoding the nucleoprotein (N), phosphoprotein (P), matrix (M), fusion (F), hemagglutinin-neuraminidase (HN), and polymerase (L) were modified singly or in combination to generate 12 viruses designated Min-N, Min-P, Min-M, Min-FHN, Min-L, Min-NP, Min-NPM, Min-NPL, Min-PM, Min-PFHN, Min-MFHN, and Min-PMFHN. CPD of N or L severely reduced growth in vitro and was not further evaluated. CPD of P or M was associated with increased and decreased interferon (IFN) response in vitro, respectively, but had little effect on virus replication. In Vero cells, CPD of F and HN delayed virus replication, but final titers were comparable to wild-type (wt) HPIV3. In human lung epithelial A549 cells, CPD F and HN induced a stronger IFN response, viral titers were reduced 100-fold, and the expression of F and HN proteins was significantly reduced without affecting N or P or the relative packaging of proteins into virions. Following intranasal infection in hamsters, replication in the nasal turbinates and lungs tended to be the most reduced for viruses bearing CPD F and HN, with maximum reductions of approximately 10-fold. Despite decreased in vivo replication (and lower expression of CPD F and HN in vitro), all viruses induced titers of serum HPIV3-neutralizing antibodies similar to wt and provided complete protection against HPIV3 challenge. In summary, CPD of HPIV3 yielded promising vaccine candidates suitable for further development.

Animals

Species-specific transcriptomic changes upon respiratory syncytial virus infection in cotton rats.

The cotton rat (Sigmodon) is the gold standard pre-clinical small animal model for respiratory viral pathogens, especially for respiratory syncytial virus (RSV). However, without a reference genome or a published transcriptome, studies requiring gene expression analysis in cotton rats are severely limited. The aims of this study were to generate a comprehensive transcriptome from multiple tissues of two species of cotton rats that are commonly used as animal models (Sigmodon fulviventer and Sigmodon hispidus), and to compare and contrast gene expression changes and immune responses to RSV infection between the two species. Transcriptomes were assembled from lung, spleen, kidney, heart, and intestines for each species with a contig N50 > 1600. Annotation of contigs generated nearly 120,000 gene annotations for each species. The transcriptomes of S. fulviventer and S. hispidus were then used to assess immune response to RSV infection. We identified 238 unique genes that are significantly differentially expressed, including several genes implicated in RSV infection (e.g., Mx2, I27L2, LY6E, Viperin, Keratin 6A, ISG15, CXCL10, CXCL11, IRF9) as well as novel genes that have not previously described in RSV research (LG3BP, SYWC, ABEC1, IIGP1, CREB1). This study presents two comprehensive transcriptome references as resources for future gene expression analysis studies in the cotton rat model, as well as provides gene sequences for mechanistic characterization of molecular pathways. Overall, our results provide generalizable insights into the effect of host genetics on host-virus interactions, as well as identify new host therapeutic targets for RSV treatment and prevention.

Animals

Whole genome sequencing and phylogenetic classification accelerate the implementation of respiratory syncytial virus genomic surveillance in Canada: a pilot study.

UNLABELLED: Whole genome sequencing (WGS) has emerged as a powerful tool to facilitate the study of existing and emerging infectious diseases. WGS-based genomic surveillance provides information on the genetic diversity and tracks the evolution of important viral pathogens, including respiratory syncytial virus (RSV). Multiplex tiling polymerase chain reaction (PCR) assays have been used to facilitate sequencing of a variety of pathogens in support of genomics-based surveillance initiatives. We developed, optimized, and implemented multiplex tiling PCR assays for RSVA and RSVB capable of generating near-complete genomes in the majority of contemporaneous specimens tested. A pilot data set comprising 52 RSVA and 37 RSVB genomes derived from Canadian clinical specimens during the 2022-2023 respiratory virus season was used to perform phylogenetic analyses using both near-complete genome and glycoprotein (G) sequences. Overall, the RSV phylogenetic tree built with whole genomes showed identical lineage clusters as compared to the G gene but was more discriminatory. Moreover, the availability of complete genomes enables the identification of a broader range of mutations. For instance, mutations identified in the fusion protein among Canadian isolates tested here, including S377N, K272M, S276N, S211N, S206I, and S209Q, could affect the efficacy of current vaccines or antiviral-based therapeutics. In conclusion, our work reinforces other recent studies demonstrating the utility of multiplex tiling PCR assays to facilitate high-throughput WGS of RSV, which is capable of supporting enhanced genomic surveillance initiatives, as well as the more comprehensive genomic analyses required to inform public health strategies for the development and usage of vaccines and antiviral drugs. IMPORTANCE: We present assays to efficiently sequence genomes of RSVA and RSVB. This enables researchers and public health agencies to acquire high-quality genomic data using rapid and cost-effective approaches. Genomic data-based comparative analysis can be used to conduct surveillance and monitor circulating isolates for efficacy of vaccines and antiviral therapeutics.

Humans

DNA sequencing for microbial surveillance in cystic fibrosis airways: advances, challenges, and clinical translation.

SUMMARYDNA sequencing has revolutionized microbial surveillance in cystic fibrosis (CF), transforming pathogen identification from culture-dependent to total microbial community identification using molecular-based approaches. Techniques such as 16S rRNA gene sequencing have uncovered the complexity of the CF airway microbiome, while shotgun metagenomics, metatranscriptomics, and viromics now provide strain-level, functional, and viral insights beyond bacterial identification. Despite these advances, key technical and logistical challenges remain, including the processing of high-viscosity sputum samples, overwhelming host DNA contamination, managing large data sets, and the integration of complex bioinformatic outputs into clinical workflows. Emerging innovations such as host DNA depletion protocols, targeted enrichment panels, and adaptive sampling on Oxford Nanopore platforms are helping to overcome these barriers, improving microbial recovery and sequencing efficiency. As cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies are changing the lives of people with cystic fibrosis (pwCF), sequencing offers an unprecedented opportunity to track potential microbial adaptation in response. This review investigates current advances, limitations, and translational opportunities in DNA sequencing for CF airway microbiome surveillance, highlighting how these technologies can help reshape research and clinical microbiology in the post-modulator era.

Cystic Fibrosis

Multidrug resistance and genomic characteristics of nontypeable Haemophilus influenzae isolates from the respiratory tract of pediatric patients.

UNLABELLED: Nontypeable Haemophilus influenzae (NTHi) is a common colonizer of the human upper respiratory tract and one of the major pathogens responsible for pediatric respiratory tract infections. Given the increasing severity of its multidrug resistance (MDR), this study comprehensively investigated the genomic characteristics of circulating NTHi isolated from sputum and bronchoalveolar lavage fluid (BALF). A total of 104 H. influenzae isolates (69 from sputum; 35 from BALF) were collected from pediatric patients between January 2024 and January 2025. All isolates underwent whole-genome sequencing and antimicrobial susceptibility testing, followed by core/pan-genome phylogenetic analysis, multilocus sequence typing (MLST), and resistome profiling. Among them, 103 were identified as NTHi. We identified 29 known sequence types (STs) and 10 novel STs, with ST-107 (14.4%), ST-57 (10.6%), and ST-11 (8.7%) being the major circulating lineages. However, core-genome phylogenetic analysis provided a more granular view of the genetic variation within these identical STs. All the isolates showed high resistance to ampicillin (98.1%) and cefuroxime (84.6%). Genomically, the multidrug efflux pump gene hmrM was ubiquitous (100%). Ampicillin resistance was predominantly driven by blaTEM-1 carriage (77.9%), with minor contributions from chromosomal ftsI mutations. Fifteen plasmid replicons were predicted from 25 isolates, which highly coincided with the carriage of blaTEM-1 and other acquired resistance genes. This study demonstrates that MDR in pediatric NTHi is primarily driven by acquired resistance genes and chromosomal mutations, with specific resistant clones persisting and enriching under clinical antibiotic pressures. These findings underscore the importance of continuous high-resolution genomic surveillance in guiding rational antibiotic stewardship. IMPORTANCE: This study highlights the critical importance of high-resolution genomic surveillance in managing pediatric nontypeable Haemophilus influenzae (NTHi) infections. By utilizing whole-genome sequencing, we uncovered the pathogen's highly dynamic population structure and complex multidrug resistance (MDR) mechanisms. Crucially, our findings reveal a strong, non-random coupling between core genomic architectures, virulence factors, and MDR elements, driven by dual environmental and pharmacological pressures. This "virulence-MDR" co-evolutionary trend underscores the persistent clinical threat of locally adapted high-risk clones. These findings provide important insights for guiding rational clinical antibiotic stewardship, optimizing treatment strategies, and improving regional infection control.

Humans

Whole-Genome Conservation Analysis for the Specific and Accurate Detection of Influenza A and B Viruses and Respiratory Syncytial Virus by Quadruplex RT-qPCR.

Influenza virus (Flu) and respiratory syncytial virus (RSV) are the primary pathogens responsible for acute respiratory infections. Both viruses are prone to mutations due to the seasonal epidemic, leading to an increasing rate of false-negative results. In this study, comprehensive meta-analyses of the genomes focusing on most conserved fragments have been performed for the four seasonal influenza viruses (two subtypes of Flu A: H1N1 and H3N2; two subtypes of Flu B: Yamagata and Victoria) and the two types of RSV: RSVA and RSVB), respectively. The most conserved sequences of 200 bp were identified as targets of the designed primer/probe sets for RT-qPCR were screened and optimized. Good sensitivities of the optimized primer/probe sets were obtained with the limits of detections of 2.95, 2.82, 1.57, 2.8, 1.19, and 2.12 copies/reaction for H1N1, H3N2, Yamagata, Victoria, RSVA and RSVB, respectively. Eventually, quadruplex qPCR using the four designed primer/probe sets can achieve simultaneous screening of the four viruses at a single tube. Furthermore, the assay's good performance in detecting target viruses from clinical throat swab samples demonstrated its potential for diagnosis of these viruses. The method, based on the identified conserved sequences and primer/probe sets, can effectively reduce false-negative results and rapidly respond to these viruses during respiratory disease outbreaks, or even before their widespread emergence, which aid in preventing outbreaks and guiding clinical treatment.

Humans

Comparative Genomic Analysis of Six Mycoplasma Gallisepticum Strains: Insights into Genetic Diversity and Antibiotic Resistance.

Mycoplasma gallisepticum (MG) is a significant pathogen that causes respiratory diseases, which have had a substantial economic impact on the poultry industry. Despite the resistance of MG to antibiotics, it is imperative to identify genetic diversity in order to develop countermeasures. In this study, the genomes of six MG strains were examined to gain deeper insights into the mutations. The data pertaining to Variant Annotation and Mutation Analysis using SnpEff, along with the calculation of mutation rates as the ratio of total mutations to the length of the genomic regions analyzed, were thoroughly examined. The comprehensive evaluation yielded a total of 25,942 variants across the six strains, underscoring substantial genetic diversity. Notably, strain S6 exhibited a preponderance of frameshift mutations. A notable finding was the presence of a mutation in the MsbA gene shared by all six strains. Furthermore, five of the six strains, with the exception of strain F99 Lab, exhibited a mutation at position 5158, which impacts a multidrug transport system. Notably, strain ATCC exhibits a distinctive mutation at position 942, while strain S6 displays a unique mutation at position 6855, which is linked to efflux ABC transporter components. Furthermore, a substantial degree of genetic variation was observed among the CrmA, GapA, and vlhA genes among the various strains. High-impact changes, such as insertions and deletions, exhibited a higher frequency in CrmA, particularly in strain S6. Conversely, nonsynonymous variations demonstrated a heightened prevalence in GapA, particularly in strain F99 Lab. The vlhA gene exhibited a spectrum of effects, ranging from synonymous mutations to high-impact mutations such as stop-gains and frameshifts, particularly in strains k5111a and k4602. The functional variations observed among the strains can be attributed to these mutations, which have the potential to alter gene expression or protein function. Furthermore, substantial mutations in the dxr and rpoC genes were associated with antibiotic resistance. These mutations underscore the ongoing evolutionary adaptations of M. gallisepticum. Consequently, there is an imperative for the revision of treatment protocols and the formulation of targeted vaccines to regulate resistance within the poultry industry.

Mycoplasma gallisepticum