Surfactant-Impregnated MOF-Coated Fabric for Antimicrobial Applications.

Since the onset of the SARS-CoV-2 pandemic, the world has witnessed over 617 million confirmed cases and more than 6.54 million confirmed deaths, but the actual totals are likely much higher. The virus has mutated at a significantly faster rate than initially projected, and positive cases continue to surge with the emergence of ever more transmissible variants. According to the CDC, and at the time of this manuscript submission, more than 77% of all current US cases are a result of the B.5 (omicron). The continued emergence of highly transmissible variants makes clear the need for more effective methods of mitigating disease spread. Herein, we have developed an antimicrobial fabric capable of destroying a myriad of microbes including betacoronaviruses. We have demonstrated the capability of this highly porous and nontoxic metal organic framework (MOF), γ-CD-MOF-1, to serve as a host for varied-length benzalkonium chlorides (BACs; active ingredient in Lysol). Molecular docking simulations predicted a binding affinity of up to -4.12 kcal·mol-1, which is comparable to that of other reported guest molecules for this MOF. Similar Raman spectra and powder X-ray diffraction patterns between the unloaded and loaded MOFs, accompanied by a decrease in the Brunauer-Emmett-Teller surface area from 616.20 and 155.55 m2 g-1 respectively, corroborate the suggested potential for pore occupation with BAC. The MOF was grown on polypropylene fabric, exposed to a BAC-loading bath, washed to remove excess BAC from the external surface, and evaluated for its microbicidal activity against various bacterial and viral classes. Significant antimicrobial character was observed against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, bacteriophage, and betacoronavirus. This study shows that a common mask material (polypropylene) can be coated with BAC-loaded γ-CD-MOF-1 while maintaining the guest molecule's antimicrobial effects.

Phage K gp102 Drives Temperature-Sensitive Antibacterial Activity on USA300 MRSA.

There is widespread interest in using obligately lytic bacteriophages ("phages") to treat human bacterial infections. Among Staphylococcus aureus infections, the USA300 lineage is a frequent cause of invasive disease. We observed that phage K, a model S. aureus myophage, exhibits temperature-sensitive growth on USA300 strains, with the wild-type phage providing poorer growth suppression in broth and forming smaller and fainter plaques at 37 °C vs. 30 °C. We isolated 65 mutants of phage K that had improved plaquing characteristics at 37 °C when compared to the parental phage. In all 65 mutants, this phenotype was attributable to loss-of-function (LoF) mutations in gp102, which encodes a protein of unknown function that has homologs only among the Herelleviridae (SPO1-like myophages infecting gram-positive bacteria). Additional experiments with representative mutants consistently showed that the temperature-sensitive plaque phenotype was specific to USA300 MRSA strains and that Gp102 disruption was correlated with improved suppression of bacterial growth in broth and improved antibacterial activity in a mouse model of upper respiratory tract infection. The same genotype and in vitro phenotypes could be replicated in close relatives of phage K. Gp102 disruption did not have a detectable effect on adsorption but did delay cell culture lysis relative to wild-type under permissive infection conditions, suggesting that gp102 conservation might be maintained by selective pressure for more rapid replication. Expression of gp102 on a plasmid was toxic to both an MSSA and a USA300 MRSA strain. Molecular modeling predicts a protein with two helix-turn-helix domains that displays some similarity to DNA-binding proteins such as transcription factors. While its function remains unclear, gp102 is a conserved gene that is important to the infection process of Kayvirus phages, and it appears that the manner in which USA300 strains defend against them at 37 °C can be overcome by gp102 LoF mutations.