CBD resistant Salmonella strains are susceptible to epsilon 34 phage tailspike protein

Abstract

The rise of antimicrobial resistance is a global public health crisis that threatens the effective control and prevention of infections. Due to the emergence of pandrug-resistant bacteria, most antibiotics have lost their efficacy. Bacteriophages or their components are known to target bacterial cell walls, cell membranes, and lipopolysaccharides (LPS) and hydrolyze them. Bacteriophages being the natural predators of pathogenic bacteria, are inevitably categorized as “human friends”, thus fulfilling the adage that “the enemy of my enemy is my friend”. Leveraging on their lethal capabilities against pathogenic bacteria, researchers are searching for more ways to overcome the current antibiotic resistance challenge. In this study, we expressed and purified epsilon 34 phage tailspike protein (E34 TSP) from the E34 TSP gene, then assessed the ability of this bacteriophage protein in the killing of two CBD-resistant strains of Salmonella spp. We also assessed the ability of the tailspike protein to cause bacteria membrane disruption, and dehydrogenase depletion. We observed that the combined treatment of CBD-resistant strains of Salmonella with CBD and E34 TSP showed poor killing ability whereas the monotreatment with E34 TSP showed considerably higher killing efficiency. This study demonstrates that the inhibition of the bacteria by E34 TSP was due in part to membrane disruption, and dehydrogenase inactivation by the protein. The results of this work provides an interesting background to highlight the crucial role phage protein such as E34 TSP could play in pathogenic bacterial control.

Understanding the Mechanisms ofSalmonellaTyphimurium resistance to Cannabidiol

“…Thus this work corroborates with other works that have shown that agents that causes envelope stress activates the transcription of spy, which then acts as envelope stress sensor. While previous work in our laboratory demonstrated that CBD caused envelope disruption [28,31], in this work, it is plausible to infer that CBD-resistant strain of S. Typhimurium which showed higher spy expression were due to the induction of the spy gene by CBD. It has been demonstrated that the spy gene could be used as a whole-cell biosensor for testing antimicrobials that target bacterial cell envelope (66,67,68).…”

“…In our previous studies, we demonstrated that repeated exposure of S. Typhimurium to CBD resulted in CBD-resistance development [31]. In this study, our primary objective was to ascertain the mechanisms S. Typhimurium employs to develop resistance to the potent CBD.…”

“…This BV4012 is S. Typhimurium LT2 strain MS1868 (a kind gift from Dr. Anthony R. Poteete, University of Massachusetts). The CBD-resistant strains were previously developed in our laboratory (31). To create CBDresistant colonies, the S. Typhimurium strains were subjected to prolonged CBD pressure.…”

“…The CBD-resistant strain has been previously developed in our lab [31]. CBD-resistant or CBDsusceptible S. Typhimurium cells were cultured to mid-log stage in LB broth only for the susceptible or CBD-tinted LB broth for the CBD-resistant strain, then 10 mL of the culture was then pelleted and resuspended with equal volume of the LB broth only, or LB broth tinted with CBD with final concentration of (0.01 mg/mL).…”

“…Notwithstanding, the rich applications of Cannabidiol (CBD) as an antimicrobial, most bacteria have developed strategies of resisting Cannabidiol (CBD) similar to most antimicrobials and this pose's threat to public health [29,30]. Recently we have demonstrated that Cannabidiol (CBD) has potent antimicrobial activity against two strains of Salmonella (Typhimurium and Newington), as compared to some common broad spectrum antibiotics such as polymyxin B, Azitromycin, and Kanamycin [28,31]. However, we observed over time that Salmonella developed resistance against Cannabidiol (CBD).…”