Viral Gastroenteritis

Aspects of Antiviral Strategies Based on Different Phototherapy Approaches: Hit by the Light

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which caused the COVID-19 pandemic spreading around the world from late 2019, served as a ruthless reminder of the threat viruses pose to global public health. The synthesis of new antiviral drugs, as well as repurposing existing products, is a long-term ongoing process which has challenged the scientific community. One solution could be an effective, accessible, and rapidly available antiviral treatment based on phototherapy (PT). PT has been used to treat several diseases, and relies on the absorption of light by endogenous molecules or exogenous photosensitizers (PS). PT has often been used in cancer treatment and prophylaxis, and as a complement to established chemotherapy and immunotherapy in combined therapeutic strategy. Besides significant applications in anticancer treatment, studies have demonstrated the beneficial impact of PT on respiratory, systemic, emerging, and oncogenic viral infections. The aim of this review was to highlight the potential of PT to combat viral infections by summarizing current progress in photodynamic, photothermal, and photoacoustic approaches. Attention is drawn to the virucidal effect of PT on systemic viruses such as the human immunodeficiency virus and human herpes viruses, including the causative agent of Kaposi sarcoma, human herpes virus (HHV8). PT has good potential for disinfection in anti-norovirus research and against pandemic viruses like SARS-CoV-2.

Specific Bacterial Cell Wall Components Influence the Stability of Coxsackievirus B3

Enteric viruses infect the mammalian gastrointestinal tract and lead to significant morbidity and mortality worldwide. Data indicate that enteric viruses can utilize intestinal bacteria to promote viral replication and pathogenesis. However, the precise interactions between enteric viruses and bacteria are unknown. Here, we examined the interaction between bacteria and coxsackievirus B3, an enteric virus from the picornavirus family. We found that bacteria enhance the infectivity of coxsackievirus B3 (CVB3) in vitro. Notably, specific bacteria are required, as Gram-negative Salmonella enterica, but not Escherichia coli, enhanced CVB3 infectivity and stability. Investigating the cell wall components of both S. enterica and E. coli revealed that structures in the O-antigen or core of lipopolysaccharide, a major component of the Gram-negative bacterial cell wall, were required for S. enterica to enhance CVB3. To determine if these requirements were necessary for similar enteric viruses, we investigated if S. enterica and E. coli enhanced infectivity of poliovirus, another enteric virus in the picornavirus family. We found that while E. coli did not enhance the infectivity of CVB3, E. coli enhanced poliovirus infectivity. Overall, these data indicate that distinct bacteria enhance CVB3 infectivity and stability, and specific enteric viruses may have differing requirements for their interactions with specific bacterial species. IMPORTANCE Previous data indicate that several enteric viruses utilize bacteria to promote intestinal infection and viral stability. Here, we show that specific bacteria and bacterial cell wall components are required to enhance infectivity and stability of coxsackievirus B3 in vitro. These requirements are likely enteric virus specific, as the bacteria for CVB3 differ from poliovirus, a closely related virus. Therefore, these data indicate that specific bacteria and their cell wall components dictate the interaction with various enteric viruses in distinct mechanisms.