An Assessment of the Viability of Lytic Phages and Their Potency against Multidrug Resistant Escherichia coli O177 Strains under Simulated Rumen Fermentation Conditions

Abstract

Preslaughter starvation and subacute ruminal acidosis in cattle are known to promote ruminal proliferation of atypical enteropathogenic Escherichia coli strains, thereby increasing the risk of meat and milk contamination. Using bacteriophages (henceforth called phages) to control these strains in the rumen is a potentially novel strategy. Therefore, this study evaluated the viability of phages and their efficacy in reducing E. coli O177 cells in a simulated ruminal fermentation system. Fourteen phage treatments were allocated to anaerobic serum bottles containing a grass hay substrate, buffered (pH 6.6–6.8) bovine rumen fluid, and E. coli O177 cells. The serum bottles were then incubated at 39 °C for 48 h. Phage titres quadratically increased with incubation time. Phage-induced reduction of E. coli O177 cell counts reached maximum values of 61.02–62.74% and 62.35–66.92% for single phages and phage cocktails, respectively. The highest E. coli O177 cell count reduction occurred in samples treated with vB_EcoM_366B (62.31%), vB_EcoM_3A1 (62.74%), vB_EcoMC3 (66.67%), vB_EcoMC4 (66.92%), and vB_EcoMC6 (66.42%) phages. In conclusion, lytic phages effectively reduced E. coli O177 cells under artificial rumen fermentation conditions, thus could be used as a biocontrol strategy in live cattle to reduce meat and milk contamination in abattoirs and milking parlours, respectively.

Molecular Aspects of the Functioning of Pathogenic Bacteria Biofilm Based on Quorum Sensing (QS) Signal-Response System and Innovative Non-Antibiotic Strategies for Their Elimination

“…[ 329 ], phiPA3 against Pseudomonas aeruginosa [ 330 ], phiRSL1 against Ralstonia sp. [ 331 ], vB_EcoM_10C2 and vB_EcoM_11B2 against E. coli O177 [ 332 ], and BPECO 19 against Escherichia coli O157:H7 [ 333 ], as well as R1-37 against Yersinia enterocolitica [ 334 ], have been determined. Several studies report the success of lytic phages against enterococci biofilms.…”

Combating Antibiotic Resistance in a One Health Context: A Plethora of Frontiers

“…The lack of additional therapeutic options and the ineffectiveness of traditional antibiotics in treating and managing harmful bacterial strains have recently accelerated the revival of phage therapy (Jaglan et al, 2022). In previous study, Montso et al (2021) demonstrated that lytic phages effectively reduced E. coli O177 cells under artificial rumen fermentation conditions, and could therefore be used as a biocontrol strategy in live cattle to reduce meat and milk contamination in slaughterhouses and milking parlors, respectively.…”