Volume 06 · Issue 02 · 2024

Chicken is an important food animal worldwide and plays an important role in human life by providing meat and eggs. Despite recent significant advances in gut microbiome studies, a comprehensive study of chicken gut bacterial, archaeal, and viral genomes remains unavailable. In this study, we constructed a chicken multi-kingdom microbiome catalog (CMKMC), including 18,201 bacterial, 225 archaeal, and 33,411 viral genomes, and annotated over 6,076,006 protein-coding genes by integrating 135 chicken gut metagenomes and publicly available metagenome-assembled genomes (MAGs) from ten countries. We found that 812 and 240 MAGs in our dataset were putative novel species and genera, respectively, far beyond what was previously reported. The newly unclassified MAGs were predominant in Phyla Firmicutes_A (n = 263), followed by Firmicutes (n = 126), Bacteroidota (n = 121), and Proteobacteria (n = 87). Most of the classified species-level viral operational taxonomic units belong to Caudovirales. Approximately, 63.24 % of chicken gut viromes are predicted to infect two or more hosts, including complete circular viruses. Moreover, we found that diverse auxiliary metabolic genes and antibiotic resistance genes were carried by viruses. Together, our CMKMC provides the largest integrated MAGs and viral genomes from the chicken gut to date, functional insights into the chicken gastrointestinal tract microbiota, and paves the way for microbial interventions for better chicken health and productivity.

The rapid spread of mobile tigecycline resistance presents a significant public health threat, particularly with the increasing prevalence of tet(X4)-positive Enterobacterales across various species. This study aimed to investigate the epidemic features and transmission dynamics of tet(X4)-positive Klebsiella pneumoniae (K. pneumoniae) through the analysis of 206 raw meats, including pork (n = 182), beef (n = 16), duck (n = 5), and chicken (n = 3). These samples were collected from schools, markets, and restaurants in Chengdu City, China. A total of 25 isolates were obtained from 13 administrative regions. All isolates exhibited resistance to tetracycline, tigecycline, ampicillin, chloramphenicol, and florfenicol. Over half of the isolates also demonstrated resistance to streptomycin (80 %), sulfamethoxazole/trimethoprim (72 %), ciprofloxacin (64 %), and ampicillin/sulbactam (56 %). Among these strains, 14 distinct sequence types (STs) were identified, revealing evidence of inter-regional clonal spread, notably among 9 K. pneumoniae ST3393. Phylogenetic analysis revealed the presence of two K. pneumoniae ST5 closely resembling hypervirulent K. pneumoniae from Jiangsu. Importantly, 12 isolates were capable of transferring tigecycline resistance to Escherichia coli J53. Further plasmid analysis showed that the tet(X4)-harboring plasmids in K. pneumoniae could be classified into four types, primarily belonging to the IncFIA(HI1)/HI1A/HI1B hybrid plasmid (n = 16) and IncFII plasmid (n = 7), which significantly contributed to the cross-species dissemination of tet(X4). In summary, this study highlights the prevalence of MDR tet(X4)-positive K. pneumoniae in Chengdu, driven predominantly by clonal expansion and plasmid-mediated horizontal gene transfer. These findings emphasize the importance of continuous surveillance of tet(X4)-positive K. pneumoniae in raw meat and the implementation of effective measures to control their spread.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has severely impacted public health. In 2022, the Omicron variant of SARS-CoV-2 rapidly became the dominant circulating variant in the local COVID-19 outbreaks in Tianjin Municipality, China. To gain a deeper understanding of the genetic variations of the Omicron variant in Tianjin, specimens from individuals who tested positive for SARS-CoV-2 between December 2021 and November 2022 were used for virus whole genome sequencing and phylogenetic analysis. A total of 1,674 high-quality Omicron sequences were obtained, consisting of 1,339 sequences from local cases belonging to 20 Phylogenetic Assignment of Named Global Outbreak (PANGO) lineages and 335 sequences from imported cases belonging to 70 lineages. Tianjin experienced five waves of local outbreaks, accompanied by multiple substitutions among subvariants, ranging from the initial BA.1.1 lineage to the subsequent BA.2, BF.7, and BA.5.2 lineages. The evolutionary rate of local strains, estimated to be 28.999 substitutions per year, and the evolutionary rate of imported strains, estimated to be 24.946 substitutions per year, were lower than that of the strains circulating globally. The additional substitutions and deletions of local strains have been used to identify and disrupt the virus transmission chains. The subvariants such as BA.5.2.48, BA.5.2.49, BF.7.14, and XBB.1 circulating in the fifth epidemic wave presented criterial immune escape mutations including S: R346T, S: L452R and S: F486V. It is essential to implement genomic surveillance strategies to investigate further the development of genomic mutation characteristics in the SARS-CoV-2 variant. This ongoing monitoring will contribute to a better understanding of the virus's genetic changes and aid in effective control measures.

Human adenoviruses (HAdVs) are major respiratory pathogens. Specifically, human adenovirus type 4 (HAdV4) and human adenovirus type 7 (HAdV7) are known for causing fever and pneumonia, with documented cases of fatalities among the population. In recent years, HAdV4/HAdV7 has been implicated in causing substantial outbreaks, leading to increased morbidity in multiple countries. Most HAdV4 and HAdV7 infections have been reported in North America, Asia, Europe, Africa, South America, Oceania, and the Middle East. Most fatalities occurred in North America (the United States) and Asia (China and Singapore). Engineered recombinant adenoviruses have played a crucial role as vaccine vectors. In this study, we constructed a recombinant adenovirus, Ad4ITRmut-Ad7E3, and evaluated it in vitro and in vivo. We observed that the replication rate of Ad4ITRmut-Ad7E3 was lower than that of the RI-67 strain, indicating that the mutation of inverted terminal repeats (ITRs) weakened the replication ability of HAdV4. Immunization of BALB/c mice with the bivalent Ad4ITRmut-Ad7E3 vaccine strain, administered by intraperitoneal injection and oral gavage, resulted in the elicitation of neutralizing antibodies targeting HAdV4 and HAdV7. This finding not only provides a novel method and technique for the efficient construction of a polyvalent recombinant adenovirus vaccine candidate against HAdV4 and HAdV7 but also against other prevalent adenovirus serotypes such as HAdV3, HAdV11, HAdV14, and HAdV55, from various regions.

The emerging viruses within the genus Henipavirus in the family Paramyxoviridae pose a great threat to public biosafety. To develop a quadruple real-time fluorescence-based quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay is pivotal for the early warning of the potential of zoonotic infectious diseases. Specific primers and probes were designed for the relatively conserved regions based on whole genome sequences of Langya virus (LayV), Mojiang virus (MojV), Nipah virus (NiV), and Cedar virus (CedV), followed by the establishment of a quadruple real-time fluorescence-based qRT-PCR detection method. No cross-reactivity was observed with other viral nucleic acids. The optimal linear detection range for LayV, MojV, NiV, and CedV was 10¹-10⁸ copies/μL, and the lower limit of detection was 10 copies/μL. Three different DNA concentrations of LayV, MojV, NiV, and CedV (10⁴, 10⁵, and 10⁶ copies/μL) were tested 14 times, achieving good repeatability. The standard deviation of the cycle threshold values for each concentration was <0.5 and the coefficient of variation was < 3 %. Furthermore, the amplification efficiency of quadruple real-time fluorescence-based qRT-PCR was > 90 %, and the correlation coefficient was > 0.99. The established quadruple real-time fluorescence-based qRT-PCR assay for the detection of LayV, MojV, NiV, and CedV exhibits good sensitivity, specificity, and repeatability. Therefore, it can be used to detect Henipavirus and other related clinical specimens.

Uganda has been implementing the Global Health Security Agenda (GHSA) since 2015 to build its capacity according to World Health Organization (WHO) Benchmarks on International Health Regulations Capacities. The country remains prone to outbreaks, with more than 20 disease outbreaks reported in the past five years, including Ebola virus disease, Crimean-Congo haemorrhagic fever, Marburg haemorrhagic fever, measles, yellow fever, coronavirus disease 2019 (COVID-19), and cholera. Antimicrobial resistance (AMR) is an ongoing challenge. Uganda scored capacity level 3 on infection prevention and control (IPC) and antimicrobial stewardship (AMS) in the 2017 Joint External Evaluation (JEE) assessment. Identified gaps were being addressed after a self-assessment in 2021. This paper describes the technical assistance approaches provided to Uganda by the Medicines, Technologies, and Pharmaceutical Services Program, funded by the United States (U.S.) Agency for International Development, and implemented by Management Sciences for Health. The program, through a One Health approach, supported systematic capacity strengthening based on the JEE’s capacity advancement framework for global health security, specifically relating to AMR. The program’s interventions impacted 32 WHO benchmark actions (7 for AMR multisectoral coordination, 16 for IPC, and 9 for AMS), contributing to Uganda's strengthened GHSA capacity. Leveraging success built on the AMR platform, the program trained 745 health workers in IPC for the Ebola virus and provided support for simulation exercises by eight district IPC teams. The program also worked with the Ministry of Health to coordinate IPC for the COVID-19 response in five health regions, covering 45 districts and reaching 5,452 health workers at 858 health facilities.

In response to problems of poor sampling quality, low sensitivity, and high demand for medical personnel regarding the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) oropharyngeal (OP) swab sampling used in China, we aimed to evaluate the diagnostic performance and acceptability of saliva-based nucleic acid amplification tests (NAATs) in China. The results showed that, using nasopharyngeal (NP) swab results as the gold standard, the overall sensitivities for saliva specimens and OP swabs were 93.3 % and 85.0 %, the specificities were 92.6 % and 93.8 %, respectively. The results of an acceptability survey showed that the scores for saliva, OP, and NP samples were 9.46 ± 1.69, 8.11 ± 2.42, and 4.58 ± 3.82 out of 10, respectively, with significant differences among the three groups (P < 0.05). With higher sensitivity, comparable specificity, and strong public preference, saliva-based NAATs represent a convenient and effective method for detecting SARS-CoV-2 in future epidemics.

The status of coinfection during the national outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.5.2 or BF.7 in China in the winter of 2022, which is suspected to contribute substantially to the overloaded severe cases, needs to be investigated. We analyzed the coinfection status of 385 severe patients infected with the Omicron variant in Guangzhou using metagenomic sequencing. We found that 317 (82.3 %) patients were coinfected with at least one additional pathogen(s), including bacteria (58.7 %), fungi (27.1 %) and viruses (73.5 %). Pseudomonas aeruginosa (P. aeruginosa) (24.2 %), Staphylococcus aureus (S. aureus) (14.0 %), and Klebsiella pneumoniae (K. pneumonia) (13.4 %) ranked as the top three coinfected bacteria. Aspergillus fumigatus (A. fumigatus) (39.5 %), Pneumocystis jirovecii (P. jirovecii) (24.4 %) and Canidia albicans (C. albicans) (22.1 %) were the top three coinfected fungi. Epstein-Barr virus (EBV) (63.1 %), Human herpesvirus 7 (HHV-7) (34.8 %), and Herpes simplex virus 1 (HSV-1) (32.6 %) were the top three coinfected viruses. Of note, the detection of multiple coinfections of potential pathogenic bacteria, fungi, and viruses, despite lacking consistent patterns, highlighted a complicated synergistic contribution to disease severity. Our study presents the most comprehensive spectrum of bacterial, fungal, and viral coinfections in Omicron-associated severe coronavirus disease 2019 (COVID-19), implying that the coinfection of conditional pathogens might synergistically deteriorate the Omicron infection outcomes.

Antibiotic resistance is an escalating global concern, leading to millions of annual fatalities. Antibiotic resistance genes (ARGs) present in bacteria equip them to withstand the effects of antibiotics. Intra- and interspecific ARGs transmission through horizontal gene transfer further exacerbates resistance dissemination. The presence of ARGs in the environment heightens the probability of human exposure via direct inhalation, ingestion, or contact with polluted air, food, or water, posing substantial biosafety and health hazards. Consequently, ARGs represent a critical focal point in public health and environmental safety and are classified as emerging contaminants. This perspective underscores the necessity to assess ARG exposure within the One Health framework and to accord greater attention to the mitigation strategies and tactics associated with ARGs.