Developing a synthetic organophosphorus-based disinfectant for Canadian chicken hatcheries

The spread of bacterial pathogens within chicken hatcheries is a growing concern. Enterococcus cecorum is a bacterium that causes infection of the chicken respiratory system and in some cases the spine, often requiring farmers to cull a portion of their flocks. Disinfectants used in hatcheries are effective, yet pathogens like E. cecorum remain problematic for both producers and hatcheries. A library of synthetic organophosphorus compounds possessing antimicrobial activities were evaluated as disinfectants for use in chicken hatcheries. After evaluating compounds 9bWC2, 9bWC3, 9cWC2, 9cWC3, and 10bW in combination with the solvents ethanol, isopropanol, dimethyl sulfoxide, and tetrahydrofuran, compound 10bW dissolved in ethanol was chosen as the most suitable compound-solvent combination based on the spectrum of activity of 10bW and the lower toxicity of ethanol. Compound 10bW was tested against environmental and egg bacterial isolates at 1 mg/mL concentrations, including E. cecorum, which was inhibited at a minimum inhibitory concentration (MIC) of 1 μg/mL in 0.12% ethanol. To assess the stability of 10bW in solution, its photosensitivity and half-life in storage were evaluated. The compound exhibited a decrease in potency on S. mutans after 24 hours of fluorescent light exposure and lost all antimicrobial activity on bacterial overlays after eighteen days of storage at 4°C. The mechanism of resistance to 10bW was also investigated by performing whole-genome sequencing on spontaneous mutants of Streptococcus mutans; however, these colonies were shown to be contaminants, suggesting that spontaneous resistance in S. mutans is not occurring. The potential for resistance evolution to 10bW was also assessed by serially passaging E. cecorum in the presence of 10bW at sub-lethal concentrations for 12 days; however, the MIC of the evolved populations was not substantially different from the parent populations. Finally, eggs having natural organic matter were treated with 256 μg/mL of 10bW dissolved in 95% ethanol, which resulted in a log reduction of 1.65 and 1.38 compared to the initial inoculum, as observed on BHI and LB plates, respectively. However, the individual 10bW and ethanol treatments did not significantly differ. The experiments performed indicate that 10bW possesses potential as a novel disinfectant for use in chicken hatcheries.

Name thesis:degree_name

Master of Science (MSc)

Level thesis:degree_level

Master's

Discipline thesis:degree_discipline

Biology

Grantor dc:publisher

Faculty of Graduate Studies and Research, University of Regina

Year dc:date.issued

2021

Author dc:creator

• Kalyniuk, Jones Taylor

Advisor dc:contributor.advisor

• Stavrinides, John

Committee member dc:contributor.committeemember

• Davis, Maria

Language dc:language.iso

en

DOI

https://doi.org/10.82465/4854

OAI identifier oai:identifier

oai:uregina.scholaris.ca:10294/14350