Antibiofilm efficacy of peptide against listeria monocytogenes and shiga toxigenic escherichia coli on equipment eurfaces

Authors: BOOMER, ASHLEY - Charles Herbert Flowers High School; YIN, HSIN-BAI - University Of Maryland; Patel, Jitu

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/6/2018
Publication Date: 4/25/2018
Citation: Boomer, A., Yin, H., Patel, J.R. 2018. Antibiofilm efficacy of peptide against listeria monocytogenes and shiga toxigenic escherichia coli on equipment eurfaces. BARC Poster Day. p.6.

Interpretive Summary:

Technical Abstract: Background: Biofilms are extracellular polymeric substance matrices that microorganisms form to protect themselves from harsh environmental conditions. The bacterial pathogens in biofilms are great concern to public health because they can exchange genetic information, survive chlorine and other chemicals used for cleaning food processing equipment; contaminate food during subsequent processing, and cause foodborne illnesses. Food industry is interested in novel antimicrobials that could kill bacteria in biofilms and prevent cross-contamination of food at processing facilities. Method: An overnight culture of Listeria Monocytogenes (F6854, 101M) or Shiga toxigenic Escherichia coli (O157:H7, O26, and O111) were inoculated with 400 mL of 10% trypticase soy broth (TSB) to obtain 6 log CFU/ml of bacterial populations in a CDC-Reactor equipped with stainless steel and polycarbonate coupons (n=144). The reactor was set at a constant flow rate of 50 ml/h of 10% TSB for 48 h. After 48 h, the coupons were removed from the reactor and biofilms were treated with peptide 1018 (IDR-1018) at 0, 10, 20, or 50 µg/ml concentrations in PBS for 24 h. Surviving bacterial populations were determined by scraping off the coupons for 30 seconds on each side and appropriate dilutions were spiral plated on Rapid Lmono agar and Sorbitol MacConkey agar for the enumeration of Listeria and E. coli, respectively. Bacterial populations (log CFU/cm2) data from the three independent experiments were analyzed using the Proc-Genmod procedure of SAS. Results: Levels of L. monocytogenes and Shiga-toxigenic E. coli biofilms recovered on untreated polycarbonate and stainless steel surfaces ranged from 5.5-6.3 log CFU/cm2 and 5.1-5.7 log CFU/cm2, respectively. The IDR-1018 at the concentrations of 10, 20, and 50 µg/ml exerted significant antibiofilm ability against L. monocytogenes and Shiga toxigenic E. coli on both surfaces (P<0.05). The effect of the treatment with IDR-1018 varied with the strains of Shiga toxigenic E. coli (P<0.05) as well as equipment surfaces. The peptide at 50 µg/ml concentrations decreased populations of E. coli O26 by 0.6-2.4 log CFU/cm2 compared to 3.0-3.5 log CFU/cm2 reduction with E. coli O157:H7 in biofilms on both surfaces (P<0.05). In general, the antimicrobial effect of peptides on biofilm-forming bacterial pathogens were more prominent on stainless steel surfaces than the polycarbonate surfaces. L. monocytogenes was more susceptible to IDR-1018 with a 2.0-4.3 log CFU/cm2 reduction after the treatments with 10-50 µg/ml peptide on both surfaces, whereas only 1.5-3.2 log CFU/cm2 reductions were observed in Shiga toxigenic E. coli. Conclusion: The peptide IDR-1018 at 10, 20 and 50 µg/ml is effective in killing Shiga toxigenic E. coli and L. monocytogenes in biofilms on equipment surfaces, and therefore, may be used as alternative sanitation treatment on food processing surfaces in plants.