Subtle differences in virus composition affect disinfection kinetics and mechanisms.

Area of Science:

• Environmental microbiology
• Virology
• Biochemistry

Background:

• Viral disinfection kinetics are well-studied, but molecular inactivation mechanisms remain unclear.
• Predicting disinfection efficacy for nonculturable viruses is challenging due to limited understanding of inactivation pathways.
• Variability in disinfection outcomes necessitates research into how viral composition influences inactivation.

Purpose of the Study:

• To investigate the impact of minor variations in viral genome and protein composition on disinfection.
• To elucidate the molecular mechanisms of inactivation for bacteriophages MS2, fr, and GA using different disinfectants.

Main Methods:

• Inactivation assays using UV254, singlet oxygen ((1)O2), free chlorine (FC), and chlorine dioxide (ClO2).
• Quantification of viral genome damage via Polymerase Chain Reaction (PCR).
• Assessment of viral protein damage using quantitative Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry and molecular dynamics simulations.

Main Results:

• Chlorine dioxide (ClO2) exhibited variable inactivation kinetics and did not damage viral genomes; free chlorine (FC), singlet oxygen ((1)O2), and UV254 did.
• UV254 and (1)O2 caused specific protein damage in MS2 and fr bacteriophages, while GA's capsid remained intact.
• Free chlorine (FC) and chlorine dioxide (ClO2) rapidly degraded capsid proteins of all three viruses, with degradation influenced by amino acid solvent-accessible surface area.

Conclusions:

• Viral inactivation mechanisms vary significantly based on the disinfectant and subtle differences in viral genome and protein composition.
• Disinfectant choice is critical, as some (like ClO2) target proteins, while others (like FC, (1)O2, UV254) can damage genomes.
• Understanding these molecular-level interactions is essential for predicting and optimizing viral disinfection strategies.