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Avian reoviruses (ARV) are a group of poultry pathogens that cause runting and stunting syndrome (RSS), a condition otherwise known as "frozen chicken", which are characterized by dramatically delayed growth in broilers. It has been known that p17, a nonstructural protein encoded by ARV, prohibits cellular proliferation by halting the cell cycle at the G2/M phase, the result of which is directly associated with the typical clinical sign of RSS. Nevertheless, the mechanism by which p17 modulates cell-cycle progression remains largely unknown. Here, we screened the interactome of ectopically expressed p17 through a yeast two-hybrid assay and identified Bub3, a cellular mitotic checkpoint protein, as a binding partner of p17. The infection of the Vero cells by ARV downregulated the Bub3 expression, while the knockdown of Bub3 alleviated the p17-modulated cell-cycle arrest during ARV infection. Remarkably, the suppression of Bub3 by RNAi in the Vero cells significantly reduced the viral mRNA and protein abundance, which eventually led to diminished virus replication. Altogether, our findings reveal that ARV p17 impedes host cell proliferation through a Bub3-dependent cell-cycle arrest, which eventually contributes to efficient virus replication. These results also unveil a hitherto unknown therapeutic target for RSS. [ABSTRACT FROM AUTHOR]

Coxiella burnetii is the etiological agent of the zoonotic disease Q fever, which is featured by its ability to replicate in acid vacuoles resembling the lysosomal network. One key virulence determinant of C. burnetii is the Dot/Icm system that transfers more than 150 effector proteins into host cells. These effectors function to construct the lysosome-like compartment permissive for bacterial replication, but the functions of most of these effectors remain elusive. In this study, we used an affinity tag purification mass spectrometry (AP-MS) approach to generate a C. burnetii-human protein-protein interaction (PPI) map involving 53 C. burnetii effectors and 3480 host proteins. This PPI map revealed that the C. burnetii effector CBU0425 (designated CirB) interacts with most subunits of the 20S core proteasome. We found that ectopically expressed CirB inhibits hydrolytic activity of the proteasome. In addition, overexpression of CirB in C. burnetii caused dramatic inhibition of proteasome activity in host cells, while knocking down CirB expression alleviated such inhibitory effects. Moreover, we showed that a region of CirB that spans residues 91–120 binds to the proteasome subunit PSMB5 (beta 5). Finally, PSMB5 knockdown promotes C. burnetii virulence, highlighting the importance of proteasome activity modulation during the course of C. burnetii infection. Author summary: As the causative agent of Q fever, C. burnetii colonizes host cells by transferring effector proteins into the host cytoplasm through its Dot/Icm secretion system to construct a replicative vacuole. The function of effectors remains largely unknown. Here, we performed a large-scale AP-MS screen to analyze the interactions among C. burnetii effectors and human proteins. These analyses found that CirB functions as an inhibitor of host proteasome activity, revealing that proteasome activity is important for intracellular survival of C. burnetii. Our data have laid the foundation for future exploring the molecular mechanisms underlying the roles of C. burnetii effectors in its virulence and for the identification of novel potential drug targets for the development of novel therapeutic treatment for C. burnetii infection. [ABSTRACT FROM AUTHOR]

Background: Coxiella burnetii (Cb) is the causative agent of the zoonotic disease Q fever which is distributed worldwide. Molecular typing of Cb strains is essential to find out the infectious source and prevent Q fever outbreaks, but there has been a lack of typing data for Cb strains in China. The aim of this study was to investigate the genotypes of Cb strains in wild rats in Yunnan Province, China. Results: Eighty-six wild rats (Rattus flavipectus) were collected in Yunnan Province and 8 of the 86 liver samples from the wild rats were positive in Cb-specific quantitative PCR (qPCR). The Cb strains from the 8 rats were then typed into 3 genotypes using 10-spacer multispacer sequence typing (MST), and 2 of the 3 genotypes were recognized as novel ones. Moreover, the Cb strains in the wild rats were all identified as genotype 1 using 6-loci multilocus variable number of tandem repeat analysis (MLVA). Conclusions: This is the first report of genotypic diversity of Cb strains from wild rats in China. Further studies are needed to explore the presence of more genotypes and to associate the genotypes circulating in the wildlife-livestock interaction with those causing human disease to further expand on the epidemiological aspects of the pathogen. [ABSTRACT FROM AUTHOR]

The genus Arcobacter has been associated with illnesses in both animals and humans, where Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii have been linked to numerous cases of gastrointestinal diseases in humans. While isolated instances of Arcobacter infection have been reported in certain areas, comprehensive data reflecting the global impact of Arcobacter infection are lacking. This meta-analysis was conducted with the objective of assessing the aggregated prevalence of Arcobacter across diverse sources on a global scale. We conducted a thorough literature search of the Scopus, PubMed, and ScienceDirect databases to identify studies published from 1992 to 2022 on Arcobacter prevalence in humans and food-producing animals. We utilized multilevel random effects meta-analysis models to gauge the average occurrence of Arcobacter and to examine various factors that could influence incidence outcomes. Seventy-five articles were included in the meta-analysis. The pooled prevalence of Arcobacter spp. from different sources was 21.9% (95% CI: 18.0%–26.1%), and the mean prevalence of A. butzleri, A. cryaerophilus, and A. skirrowii was 15.1%, 2.8%, and 0.1%, respectively. Arcobacter spp. had the lowest prevalence in humans (1.8%; 95% CI: 0.7%–3.3%) and the highest in broilers (38.8%; 95% CI: 28.0%–50.1%). Among animal-derived food products, carcasses or carcass parts exhibited the highest Arcobacter spp. prevalence of 28.6% (28.6%; 95% CI: 23.7%–33.7%). This meta-analysis revealed that A. butzleri is the most prevalent Arcobacter species worldwide, with broilers, as well as seafood, being the primary hosts of Arcobacter spp. We recommend developing appropriate prevention strategies and conducting further local in-depth studies to establish the actual epidemiological burden of Arcobacter. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs), as post-transcriptional regulators, play important roles in the process of viral infection through inhibiting virus replication or modulating host immune response. However, the role of miRNAs in host response against infectious bursal disease virus (IBDV) infection is still unclear. In this study, we found that gga-miR-454 of the host was decreased in response to IBDV infection and that transfection of DF-1 cells with miR-454 inhibited IBDV replication via directly targeting the specific sequence of IBDV genomic segment B, while blockage of endogenous miR-454 by inhibitors enhanced virus replication. Furthermore, gga-miR-454 increased the expression of IFN-β by targeting Suppressors of Cytokine Signaling 6 (SOCS6), enhancing the antiviral response of host cells. These findings highlight a crucial role of gga-miR-454 in host defense against IBDV infection. [ABSTRACT FROM AUTHOR]

Objectives To identify novel genetic elements facilitating the horizontal transfer of the oxazolidinone/phenicol resistance gene optrA and the pleuromutilin–lincosamide–streptogramin A resistance gene lsa (E) in Streptococcus suis. Methods The complete genomes of S. suis HB18 and two transconjugants were obtained using both the Illumina and Nanopore platforms. MICs were determined by broth microdilution. Inverse PCR was performed to identify circular forms of the novel unconventional circularizable structure (UCS), genomic island (GI) and integrative and conjugative element (ICE). Conjugation experiments assessed the transferability of optrA and lsa (E) genes in S. suis. Results S. suis HB18 carried a multiresistance gene cluster optrA - lsa (E) -lnu (B)- aphA - aadE - spw. This gene cluster, flanked by intact and truncated erm (B) in the same orientation, resided on a novel ICES su HB18. Inverse PCR revealed the existence of a novel UCS, named UCS- optrA  + l sa (E), which could excise the gene cluster optrA - lsa (E) -lnu (B)- aphA - aadE - spw and one copy of erm (B) from ICE Ssu HB18. Two transconjugants with different characteristics were obtained. In transconjugant T-JH-GI, UCS- optrA  + l sa (E) excised from ICE Ssu HB18 inserted into the erm (B)-positive GI, designated GI Ssu HB18, generating the novel GI Ssu HB18-1. Meanwhile, in T-JH-ICE, genetic rearrangement events occurred in ICE Ssu HB18 and GI Ssu HB18, forming the novel ICE Ssu HB18-1. Conclusions This is the first report demonstrating the functionally active UCS- optrA  + l sa (E) excising from ICE Ssu HB18 and inserting into the erm (B)-positive GI Ssu HB18 during the conjugation process. The location of optrA and lsa (E) on a multiresistance UCS enhances its persistence and dissemination. [ABSTRACT FROM AUTHOR]

Streptococcus suis (S. suis) has emerged as a prevalent bacterial pathogen within the swine industry, posing a substantial zoonotic threat to global public health. As an inhabitant of the upper respiratory tracts of animals, S. suis possesses a sophisticated array of virulence-related factors that enable it to breach cellular barriers and induce multisystem inflammation, notably causing meningitis. This review synthesizes current research findings to provide insights into the complicated virulence-related factors employed by S. suis. Special emphasis is given to factors crucial for penetrating the host blood–brain barrier (BBB). By summarizing existing knowledge, this review lays the groundwork for future advanced investigations, paving the way for a deeper understanding of S. suis pathogenesis and potential therapeutic interventions. Specifically, comprehensive explorations to unravel the expression dynamics of these virulence-related factors and elucidate the unique pathogenic mechanisms that operate during host attacks could contribute to clinical treatment strategies and advance innovations in vaccine development. [ABSTRACT FROM AUTHOR]

The emergence of mobilized colistin resistance (mcr) genes has raised significant concerns as they pose a public health issue. The prevalence of mcr genes, particularly the newly discovered mcr-9 gene, in non-typhoidal Salmonella (NTS) isolates remains unclear. We characterized mcr-9.1-producing NTS isolates from China. Among 7,106 NTS isolates from diarrhea cases in 32 provinces during 2010–2020, 11 mcr-9.1-producing isolates were identified and were all not resistant to colistin. Five isolates belonged to Salmonella Thompson and sequence type (ST) 26, two belonged to Salmonella Typhimurium and ST34, two belonged to Salmonella Typhimurium and ST36, and two belonged to Salmonella 1,4,[5],12:i:- and ST34. Plasmids harboring mcr-9.1 tended to possess the IncHI2 backbone and were ~ 300 kb long. All mcr-9.1 genes shared the same flanking sequence, rcnR-rcnA-pcoS-IS903-mcr-9.1-wbuC. According to the NCBI data, we found that NTS serves as the primary host of mcr-9.1, although the prevalence of specific serotypes differed between domestic and international settings. Notably, most data came from developed countries, such as the USA. mcr-9.1 tended to be transferred as a gene cassette or to be mobilized by a conjugational plasmid in multiple bacteria across humans, animals, and the environment. Furthermore, mcr-9.1 frequently co-existed and was co-transferred with various genes encoding resistance to first-line drugs, reducing the effectiveness of available therapeutic options. In summary, although mcr-9 does not mediate colistin resistance, it can silently spread with some genes encoding resistance to first-line drugs, and therefore warrants research attention. [ABSTRACT FROM AUTHOR]

Human Q fever is recognized as a worldwide public health problem. It often occurs by inhalation of airborne aerosols contaminated with Coxiella burnetii , a gram-negative intracellular bacterium, mainly from domestic livestock. In this study, we analyzed the possibility to establish mucosal and systemic immunity against C. burnetii infection using a pulmonary delivery of chloroform-methanol residue of C. burnetii (CMR) vaccine. Mice were immunized by the intratracheal inoculation of CMR (IT-CMR) or the subcutaneous injection of CMR (SC-CMR), and the immunized mice were challenged with C. burnetii by the intratracheal route. The levels of IFN-γ, IL-12p70, IL-5, and IL-4 in the IT-CMR group in splenic T cells stimulated ex vivo were significantly higher than in the SC-CMR group. Significantly elevated sIgA to C. burnetii was detected in the bronchoalveolar lavage fluid of mice immunized by IT-CMR but not by SC-CMR, which might have contributed to the significant reduction in C. burnetii load and pathological lesions in the lungs of the mice after the challenge of C. burnetii. These results suggest that compared with SC-CMR in mice, IT-CMR was more efficient to elicit cellular and lung mucosal immune responses against aerosol infection of C. burnetii. [ABSTRACT FROM AUTHOR]

Highlights • FAdV-4 inhibits LMH cell growth and this inhibition can be abolished by SP600125. • SP600125 markedly suppresses FAdV-4-induced phosphorylation of p38 and JNK MAPK. • SP600125 induces interferon production associated with inhibition of FAdV-4 growth.. Abstract Fowl Adenoviruses (FAdVs) are widely-distributed pathogens across the globe. Fowl adenovirus serotype 4 (FAdV-4), the causative agent for chicken hydropericardium syndrome (HPS) with a high mortality in the infected flocks, has caused severe economic losses to the poultry industry of China in the past few years. Although vaccination against FAdV-4 has been implemented, the prevention and control of FAdV-4 infection is still not very successful. Here, we report that FAdV-4 markedly inhibits Leghorn male hepatoma (LMH) cell growth and this inhibition could be abolished by a small molecule SP600125, a JNK MAPK specific inhibitor. Furthermore, SP600125 considerably suppressed FAdV-4-induced phosphorylation of p38 and JNK MAPK. Importantly, SP600125 promoted type I interferon production associated with inhibition of FAdV-4 replication. Thus, FAdV-4 might employ the JNK MAPK pathway for the benefit of its replication, and SP600125 may have the potential of being used as an anti-virus drug for the control FAdV-4 infection. [ABSTRACT FROM AUTHOR]

Viruses have developed a variety of methods to evade host immune response. Our previous study showed that infectious bursal disease virus (IBDV) inhibited type I interferon production via interaction of VP4 with cellular glucocorticoid-induced leucine zipper (GILZ) protein. However, the exact underlying molecular mechanism is still unclear. In this study, we found that IBDV VP4 suppressed GILZ degradation by inhibiting K48-linked ubiquitylation of GILZ. Furthermore, mutation of VP4 (R41G) abolished the inhibitory effect of VP4 on IFN-β expression and GILZ ubiquitylation, indicating that the amino acid 41R of VP4 was required for the suppression of IFN-β expression and GILZ ubiquitylation. Moreover, IBDV infection or VP4 expression markedly inhibited endogenous GILZ ubiquitylation. Thus, IBDV VP4 suppresses type I interferon expression by inhibiting K48-linked ubiquitylation of GILZ, revealing a new mechanism employed by IBDV to suppress host response. [ABSTRACT FROM AUTHOR]

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive avian disease caused by IBD virus (IBDV). IBDV VP3 is a multifunctional protein playing a key role in virus assembly and pathogenesis. To investigate the role of VP3 in pathogenesis, we transfected DF-1 cells with pRK5-FLAG-vp3 and found that VP3 enhanced type I interferon expression and suppressed IBDV replication. Furthermore we found that VP3 interacted with chicken Ribosomal Protein L18 (chRPL18) in host cells and knockdown of chRPL18 by RNAi significantly promoted Type I interferon expression and inhibited IBDV replication. Moreover, our data show that chicken double-stranded RNA-activated protein kinase (chPKR) interacted with both VP3 and chRPL18. Thus chRPL18 in association with VP3 and chPKR affects viral replication. [ABSTRACT FROM AUTHOR]

Background: Hard ticks act as arthropod vectors in the transmission of human and animal pathogens and are widely distributed in northern China. The aim of this study is to screen the important tick-borne pathogens (TBPs) carried by hard ticks in Inner Mongolia using metagenomic next-generation sequencing (mNGS) and to estimate the risk of human infection imposed by tick bites. Methods: The adult Dermacentor nuttalli (n = 203) and Ixodes persulcatus (n = 36) ticks feeding on cattle were collected. The pooled DNA samples prepared from these ticks were sequenced as the templates for mNGS to survey the presence of TBPs at the genus level. Individual tick DNA samples were detected by genus--specific or group-specific nested polymerase chain reaction (PCR) of these TBPs and combined with DNA sequencing assay to confirm the results of mNGS. Results: R. raoultii (45.32%, 92/203), Candidatus R. tarasevichiae (5.42%, 11/203), Anaplasma sp. Mongolia (26.60%, 54/203), Coxiella-like endosymbiont (CLE) (53.69%, 109/203), and Babesia venatorum (7.88%, 16/203) were detected in D. nuttalli, while R. raoultii (30.56%, 11/36), Anaplasma sp. Mongolia (27.80%, 10/36), and CLE (27.80%, 10/36) were detected in I. persulcatus. The double- and triple-pathogen/endosymbiont co-infections were detected in 40.39% of D. nuttalli and 13.89% of I. persulcatus, respectively. The dual co-infection with R. raoultii and CLE (14.29%, 29/203) and triple co-infection with R. raoultii, Anaplasma sp. Mongolia, and CLE (13.79%, 28/203) were most frequent in D. nuttalli. Conclusions: This study provides insight into the microbial diversity of D. nuttalli and I. persulcatus in Inner Mongolia, China, reporting for the first time that Candidatus R. tarasevichiae had been found in D. nuttalli in China, and for the first time in the world that Anaplasma sp. Mongolia has been detected in I. persulcatus. This study proves that various vertically transmitted pathogens co-inhabit D. nuttalli and I. persulcatus, and indicates that cattle in Inner Mongolia are exposed to several TBPs. [ABSTRACT FROM AUTHOR]

Q fever is a worldwide zoonosis caused by Coxiella burnetii (Cb). From January 2018 to November 2019, plasma samples from 2,382 patients with acute fever of unknown cause at a hospital in Zhuhai city of China were tested using metagenomic next-generation sequencing (mNGS). Of those tested, 138 patients (5.8%) were diagnosed with Q fever based on the presence of Cb genomic DNA detected by mNGS. Among these, 78 cases (56.5%) presented from Nov 2018 to Mar 2019, suggesting an outbreak of Q fever. 55 cases with detailed clinical information that occurred during the outbreak period were used for further analysis. The vast majority of plasma samples from those Cb-mNGS-positive patients were positive in a Cb-specific quantitative polymerase chain reaction (n = 38) and/or indirect immunofluorescence assay (n = 26). Mobile phone tracing data was used to define the area of infection during the outbreak. This suggested the probable infection source was Cb-infected goats and cattle at the only official authorized slaughterhouse in Zhuhai city. Phylogenic analysis based on genomic sequences indicated Cb strains identified in the patients, goat and cattle were formed a single branch, most closely related to the genomic group of Cb dominated by strains isolated from goats. Our study demonstrates Q fever was epidemic in 2018–2019 in Zhuhai city, and this is the first confirmed epidemic of Q fever in a contemporary city in China. Author summary: Generally, the clinical diagnosis of acute Q fever, which is caused by Coxiella burnetii, is based on serologic methods that detect the presence antibodies produced by the body to fight the infection. However, the lag time between becoming infected and production of antibodies limits early diagnosis using this method. Here, we confirmed an epidemic of human Q fever in Zhuhai, a contemporary city in China, using clinical metagenomic next-generation sequencing (mNGS) and cell phone location data. Our results indicate that Cb-infected goats and cattle at the only official authorized slaughterhouse in Zhuhai were the likely infection source for the Q fever epidemic. More importantly, we demonstrate that mNGS is a useful tool for rapid and effective public health responses to acute bacterial infections. [ABSTRACT FROM AUTHOR]

Background: Hard ticks act as arthropod vectors in the transmission of human and animal pathogens and are widely distributed in northern China. The aim of this study is to screen the important tick-borne pathogens (TBPs) carried by hard ticks in Inner Mongolia using metagenomic next-generation sequencing (mNGS) and to estimate the risk of human infection imposed by tick bites. Methods: The adult Dermacentor nuttalli (n = 203) and Ixodes persulcatus (n = 36) ticks feeding on cattle were collected. The pooled DNA samples prepared from these ticks were sequenced as the templates for mNGS to survey the presence of TBPs at the genus level. Individual tick DNA samples were detected by genus--specific or group-specific nested polymerase chain reaction (PCR) of these TBPs and combined with DNA sequencing assay to confirm the results of mNGS. Results: R. raoultii (45.32%, 92/203), Candidatus R. tarasevichiae (5.42%, 11/203), Anaplasma sp. Mongolia (26.60%, 54/203), Coxiella-like endosymbiont (CLE) (53.69%, 109/203), and Babesia venatorum (7.88%, 16/203) were detected in D. nuttalli, while R. raoultii (30.56%, 11/36), Anaplasma sp. Mongolia (27.80%, 10/36), and CLE (27.80%, 10/36) were detected in I. persulcatus. The double- and triple-pathogen/endosymbiont co-infections were detected in 40.39% of D. nuttalli and 13.89% of I. persulcatus, respectively. The dual co-infection with R. raoultii and CLE (14.29%, 29/203) and triple co-infection with R. raoultii, Anaplasma sp. Mongolia, and CLE (13.79%, 28/203) were most frequent in D. nuttalli. Conclusions: This study provides insight into the microbial diversity of D. nuttalli and I. persulcatus in Inner Mongolia, China, reporting for the first time that Candidatus R. tarasevichiae had been found in D. nuttalli in China, and for the first time in the world that Anaplasma sp. Mongolia has been detected in I. persulcatus. This study proves that various vertically transmitted pathogens co-inhabit D. nuttalli and I. persulcatus, and indicates that cattle in Inner Mongolia are exposed to several TBPs. [ABSTRACT FROM AUTHOR]

Background: Coxiella burnetii is an obligate intracellular Gram-negative bacterium that causes a zoonotic disease commonly called Q fever globally. In this study, an up-converting phosphor technology-based lateral flow (UPT-LF) assay was established for the rapid and specific detection of phase I strains of C. burnetii. Results: Specific monoclonal antibodies (10B5 and 10G7) against C. burnetii phase I strains were prepared and selected for use in the UPT-LF assay by the double-antibody-sandwich method. The detection sensitivity of the Coxiella-UPT-LF was 5 × 104 GE/ml for a purified C. burnetii phase I strain and 10 ng/ml for LPS of C. burnetii Nine Mile phase I (NMI). Good linearity was observed for C. burnetii phase I and NMI LPS quantification (R2 ≥ 0.989). The UPT-LF assay also exhibited a high specificity to C. burnetii, without false-positive results even at 108 GE/ml of non-specific bacteria, and good inclusivity for detecting different phase I strains of C. burnetii. Moreover, the performance of the Coxiella-UPT-LF assay was further confirmed using experimentally and naturally infected samples. Conclusions: Our results indicate that Coxiella-UPT-LF is a sensitive and reliable method for rapid screening of C. burnetii, suitable for on-site detection in the field. [ABSTRACT FROM AUTHOR]

Q fever is a worldwide zoonosis caused by Coxiella burnetii. Human Q fever is typically acquired through inhalation of contaminated aerosols, resulting in an initial pulmonary infection. In this study, BALB/c mice were infected with C. burnetii via an intratracheal (IT) route using a non-invasive aerosol pulmonary delivery device to directly place the living C. burnetii organisms into the lungs of the mice. The bacterial loads, pathological lesions, and antibody and cellular responses were analyzed and compared with those of mice infected via an intraperitoneal (IP) route. Compared with mice infected via an IP route, mice infected via an IT route exhibited a higher bacterial load and more severe pathological lesions in the heart and lungs at days 3 and 7 post-infection (pi). The levels of interferon-γ and IL-12p70 in the serum of mice infected via the IT route were significantly higher than those of mice infected via the IP route at day 3 pi. In conclusion, this murine model of acute C. burnetii infection via IT inoculation closely resembles the natural route of C. burnetii infection than that of IP injection. Thus, this newly developed model will be useful for investigating the pathogenesis and immunity of C. burnetii aerosol infection, as well as for the evaluation of therapeutic drugs and preventive vaccines of Q fever. [ABSTRACT FROM AUTHOR]