Inhibition of Listeria monocytogenes by Phage Lytic Enzymes Displayed on Tailored Bioparticles

Listeria monocytogenes is a foodborne pathogen that is often associated with ready-to-eat food products such as deli meats, mixed salads, fresh dairy products, and leafy greens .

If consumed in a contaminated food product, the organism can cause listeriosis; this is a rare but serious illness, particularly for at-risk groups including the young, the elderly, and the immunocompromised .The high mortality rate (20–30%) associated with the illness has resulted in stringent detection and control measures for L. monocytogenes in food processing environments.

Despite these controls, the physiological resistance of the organism against low temperatures and high salt concentrations, and its ability to form biofilms, makes this pathogen difficult to manage [1].

Bacteriophage-derived enzymes can be applied as biocontrol agents to target specific foodborne pathogens. We investigated the ability of a listeriophage endolysin and derivatives thereof, fused to polyhydroxyalkanoate bionanoparticles (PHA_BNPs), to lyse and inhibit the growth of L. monocytogenes.

application of Bionanoparticles

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Bionanoparticles (BNPs) displaying only the amidase domain of the phage endolysin were more effective at inhibiting growth under laboratory conditions (37 °C, 3 × 107 CFU/mL) than BNPs displaying the full-length endolysin (89% vs. 83% inhibition). Under conditions that better represent those found in food processing environments (22 °C, 1 × 103 CFU/mL), BNPs displaying the full-length endolysin demonstrated a greater inhibitory effect compared to BNPs displaying only the amidase domain (61% vs. 54% inhibition).

[2]

The CDC estimates that Listeria, a rare but deadly germ, is the third leading cause of death from food poisoning in the United States.

Turbidity Reduction Assays

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

When applied at 37 °C to 1 × 107 CFU/mL of L. monocytogenes strain 473, the addition of Lysin293_BNPs (orange) resulted in a reduction in turbidity of 76.7% and 80% after 30 min, compared to the control without BNPs (white) and with BNPs without lysin (blue), respectively. Under the same conditions, the application of Amidase293_BNPs resulted in a reduction in turbidity of 76.8% and 81.5%, compared to the respective controls.

The results are promising

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

The results are promising and show an initial proof-of-concept for the use of PHA_BNPs displaying listeriophage lysins as a potential biocontrol agent against L. monocytogenes. An advantage of using this technology over chemical-based sanitizers or chemical-inhibition techniques is that these BNPs are biodegradable and, therefore, could be released in the food processing plant and naturally degraded over time, thus posing no threat to human health.

[3]

Listeria monocytogenes, image by Dennis Kunkel Microscopy, Inc

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Inhibition of Listeria monocytogenes by Phage Lytic Enzymes Displayed on Tailored Bioparticles

Listeria monocytogenes is a foodborne pathogen that is often associated with ready-to-eat food products such as deli meats, mixed salads, fresh dairy products, and leafy greens .

If consumed in a contaminated food product, the organism can cause listeriosis; this is a rare but serious illness, particularly for at-risk groups including the young, the elderly, and the immunocompromised .The high mortality rate (20–30%) associated with the illness has resulted in stringent detection and control measures for L. monocytogenes in food processing environments.

Despite these controls, the physiological resistance of the organism against low temperatures and high salt concentrations, and its ability to form biofilms, makes this pathogen difficult to manage [1].

Bacteriophage-derived enzymes can be applied as biocontrol agents to target specific foodborne pathogens. We investigated the ability of a listeriophage endolysin and derivatives thereof, fused to polyhydroxyalkanoate bionanoparticles (PHA_BNPs), to lyse and inhibit the growth of L. monocytogenes.

application of Bionanoparticles

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Bionanoparticles (BNPs) displaying only the amidase domain of the phage endolysin were more effective at inhibiting growth under laboratory conditions (37 °C, 3 × 107 CFU/mL) than BNPs displaying the full-length endolysin (89% vs. 83% inhibition). Under conditions that better represent those found in food processing environments (22 °C, 1 × 103 CFU/mL), BNPs displaying the full-length endolysin demonstrated a greater inhibitory effect compared to BNPs displaying only the amidase domain (61% vs. 54% inhibition).

[2]

The CDC estimates that Listeria, a rare but deadly germ, is the third leading cause of death from food poisoning in the United States.

Turbidity Reduction Assays

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

When applied at 37 °C to 1 × 107 CFU/mL of L. monocytogenes strain 473, the addition of Lysin293_BNPs (orange) resulted in a reduction in turbidity of 76.7% and 80% after 30 min, compared to the control without BNPs (white) and with BNPs without lysin (blue), respectively. Under the same conditions, the application of Amidase293_BNPs resulted in a reduction in turbidity of 76.8% and 81.5%, compared to the respective controls.

The results are promising

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

The results are promising and show an initial proof-of-concept for the use of PHA_BNPs displaying listeriophage lysins as a potential biocontrol agent against L. monocytogenes. An advantage of using this technology over chemical-based sanitizers or chemical-inhibition techniques is that these BNPs are biodegradable and, therefore, could be released in the food processing plant and naturally degraded over time, thus posing no threat to human health.

[3]

Listeria monocytogenes, image by Dennis Kunkel Microscopy, Inc

Have a question about the programme?

Get in contact with us below!
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.