Genetic Transferability of Anomalous Irradiation Alterations of Antibiotic Activity

TL;DR

This study shows that irradiation-induced changes in antibiotic activity can be transferred genetically between bacteria, affecting their growth response to irradiated antibiotics, with potential implications for understanding antibiotic resistance mechanisms.

Contribution

It demonstrates that irradiation effects on antibiotic activity are transferable via genetic elements, linking physical modification to genetic transfer of resistance traits.

Findings

Irradiated chloramphenicol enhances growth in resistant strains.

Irradiation decreases growth in sensitive strains.

Transfer of irradiation effects correlates with genetic resistance determinants.

Abstract

It previously has been discovered that visible light irradiation of crystalline substrates can lead to enhancement of subsequent enzymatic reaction rates as sharply peaked oscillatory functions of irradiation time. The particular activating irradiation times can vary with source of a given enzyme and thus, presumably, its molecular structure. The experiments reported here demonstrate that the potential for this anomalous enzyme reaction rate enhancement can be transferred from one bacterial species to another coincident with transfer of the genetic determinant for the relevant enzyme. In particular, the effect of crystal-irradiated chloramphenicol on growth of bacterial strains in which a transferable R-factor DNA plasmid coding for chloramphenicol resistance was or was not present (S. panama R+, E. coli R+, and E. coli R-) was determined. Chloramphenicol samples irradiated 10, 35 and 60 sec produced increased growth rates (diminished inhibition) for the resistant S. panama and E. coli strains, while having no such effect on growth rate of the sensitive E. coli strain. Consistent with past findings, chloramphenicol samples irradiated 5, 30 and 55 sec produced decreased growth rates (increased inhibition) for all three strains.