Viruses

The frequent emergence of highly pathogenic viruses globally has persistently threatened global health [...]

Shiga toxin-producing Escherichia coli (STEC) pose a significant threat to public health and effective methods of detection are needed. The use of naturally occurring bacteriophages (phages) to detect E. coli has been well documented. However, detecting multiple serotypes at the same time often required multiple phages specific to individual serotypes. To limit the burden of complex cocktails, this study aimed to engineer phages with an expanded host range that allows each phage to contribute to detection across multiple STEC serogroups. Kutterviruses, in the Ackermannviridae family, contain four tailspike proteins (TSPs), each of which confers tropism to a different bacterial strain. The modular nature of TSPs allows for mixing receptor-binding domains from diverse phage types. The host range of the Kuttervirus CBA120 was modified by replacing its native tailspike proteins (TSPs) with chimeric versions incorporating receptor-binding domains from related and unrelated phages. A structure-guided approach was utilized to overcome minimal sequence similarity between donor and recipient phages and achieve novel functional TSP chimeras. Two engineered phage variants were created that collectively detect five STEC serogroups: O26, O45, O103, O111, and O157. Spotting and luciferase assays confirmed that the replacement TSPs were functional and the phages had acquired new host ranges. This study demonstrates the feasibility of engineering Ackermannviridae phages with customized host ranges for detecting multiple STEC strains. This approach has potential applications in developing improved phage-based bacterial detection, therapy, and biocontrol.

Hendra virus (HeV) is a highly pathogenic zoonotic paramyxovirus that poses a serious threat to human and equine health, yet no approved antivirals or vaccines currently exist. RNA-dependent RNA polymerase (RdRp) of Hendra virus represents a critical and attractive target for antiviral drug development, given its essential role in both viral genome replication and mRNA transcription. Due to the lack of a human homolog, it is more druggable and less likely to cause host toxicity. Its sequence conservation among related paramyxoviruses further highlights its potential for the development of broad-spectrum inhibitors. This study offers the first comprehensive computational analysis of the Hendra virus RdRp, potentially promising FDA-approved drugs as possible inhibitors. A homology model of RdRp was generated in the absence of experimental three-dimensional (3D) structure, followed by virtual screening and molecular dynamics (MD) simulations to evaluate the drug binding and stability. Based on the highest energy, four FDA-approved drugs selected were menadiol diphosphate (−49.88 kcal/mol), masoprocol (−39.69 kcal/mol), pamidronic acid (−34.29 kcal/mol), and dinoprostone (−46.90 kcal/mol). Furthermore, these compounds exhibited significant interactions with the catalytic GDNE motif. With strong conformational stability and pharmacokinetic profile, masoprocol and menadiol diphosphate showed the most stable and energetically favorable interactions within the RdRp active site. These findings suggest their potential as repurposed therapeutic candidates against Hendra virus infection and they provide a structural basis for the development of broad-spectrum paramyxovirus inhibitors, justifying additional experimental confirmation.