tetano
Editor, Senior Moderator
Microbiol Spectr
. 2026 Jun 15:e0297825.
doi: 10.1128/spectrum.02978-25. Online ahead of print.
Direct interaction between avian pathogenic Escherichia coli and H9N2 avian influenza virus promotes bacterial adhesion during their infections
Yue Li[SUP] 1 [/SUP], Yulu Xue[SUP] 1 [/SUP], Yuji Quan[SUP] 1 [/SUP], Peng Chen[SUP] 1 [/SUP], Xiangkai Zhuge[SUP] 2 [/SUP], Tao Qin[SUP] 1 3 4 5 [/SUP], Sujuan Chen[SUP] 1 3 4 5 [/SUP], Daxin Peng[SUP] 1 3 4 5 [/SUP], Xiufan Liu[SUP] 1 3 4 [/SUP]
Affiliations
H9N2 subtype avian influenza virus (AIV) and avian pathogenic Escherichia coli (APEC) are prevalent pathogens in the poultry industry, and their co-infection results in synergistic pathogenicity in chickens and significant economic losses. However, the direct interactions between H9N2 AIV and APEC during infection remain unclear. We preincubated H9N2 AIV particles with APEC and found that H9N2 AIV could bind directly to the surface of APEC. The H9N2 AIV-APEC complex enhanced bacterial adhesion to chicken embryo fibroblasts and chicken macrophages (HD11), which could be inhibited by antiserum against H9N2 AIV. The chicken challenge experiment demonstrated that the complex caused significant reductions in body weight, increased bacterial loading in various organs, and resulted in more severe histopathological lesions than APEC alone. However, the complex did not affect virus replication and shedding but elicited a robust hemagglutination inhibition antibody response when compared to H9N2 AIV alone. Additionally, we found that a 3 h interaction between H9N2 AIV and APEC in the complex led to significant morphological changes in the viral envelope, ultimately resulting in the inhibition of virus replication in vivo. These findings suggest that the direct interaction between H9N2 AIV and APEC is more conducive to bacterial infection, providing new insights into the synergistic interaction between bacteria and influenza viruses during the early stages of co-infection with H9N2 AIV and APEC.IMPORTANCEH9N2 subtype avian influenza virus and avian pathogenic Escherichia coli are common pathogens in the poultry industry. Their co-infection causes more severe harm and leads to substantial economic losses for the industry, yet the direct interaction between them remained unclear previously. Studies have found that they can bind directly; the formed complex facilitates bacterial invasion of chicken hosts and results in more severe damage. This uncovers the key reason for the greater harm of co-infection, providing a new direction for the prevention and control of such diseases in the poultry industry.
Keywords: H9N2 avian influenza virus; adhesion; avian pathogenic Escherichia coli; complex; pathogenesis.
. 2026 Jun 15:e0297825.
doi: 10.1128/spectrum.02978-25. Online ahead of print.
Direct interaction between avian pathogenic Escherichia coli and H9N2 avian influenza virus promotes bacterial adhesion during their infections
Yue Li[SUP] 1 [/SUP], Yulu Xue[SUP] 1 [/SUP], Yuji Quan[SUP] 1 [/SUP], Peng Chen[SUP] 1 [/SUP], Xiangkai Zhuge[SUP] 2 [/SUP], Tao Qin[SUP] 1 3 4 5 [/SUP], Sujuan Chen[SUP] 1 3 4 5 [/SUP], Daxin Peng[SUP] 1 3 4 5 [/SUP], Xiufan Liu[SUP] 1 3 4 [/SUP]
Affiliations
- PMID: 42294695
- DOI: 10.1128/spectrum.02978-25
H9N2 subtype avian influenza virus (AIV) and avian pathogenic Escherichia coli (APEC) are prevalent pathogens in the poultry industry, and their co-infection results in synergistic pathogenicity in chickens and significant economic losses. However, the direct interactions between H9N2 AIV and APEC during infection remain unclear. We preincubated H9N2 AIV particles with APEC and found that H9N2 AIV could bind directly to the surface of APEC. The H9N2 AIV-APEC complex enhanced bacterial adhesion to chicken embryo fibroblasts and chicken macrophages (HD11), which could be inhibited by antiserum against H9N2 AIV. The chicken challenge experiment demonstrated that the complex caused significant reductions in body weight, increased bacterial loading in various organs, and resulted in more severe histopathological lesions than APEC alone. However, the complex did not affect virus replication and shedding but elicited a robust hemagglutination inhibition antibody response when compared to H9N2 AIV alone. Additionally, we found that a 3 h interaction between H9N2 AIV and APEC in the complex led to significant morphological changes in the viral envelope, ultimately resulting in the inhibition of virus replication in vivo. These findings suggest that the direct interaction between H9N2 AIV and APEC is more conducive to bacterial infection, providing new insights into the synergistic interaction between bacteria and influenza viruses during the early stages of co-infection with H9N2 AIV and APEC.IMPORTANCEH9N2 subtype avian influenza virus and avian pathogenic Escherichia coli are common pathogens in the poultry industry. Their co-infection causes more severe harm and leads to substantial economic losses for the industry, yet the direct interaction between them remained unclear previously. Studies have found that they can bind directly; the formed complex facilitates bacterial invasion of chicken hosts and results in more severe damage. This uncovers the key reason for the greater harm of co-infection, providing a new direction for the prevention and control of such diseases in the poultry industry.
Keywords: H9N2 avian influenza virus; adhesion; avian pathogenic Escherichia coli; complex; pathogenesis.