Bacteriophages specific to Shiga toxin-producing Escherichia coli exist in goat feces and associated environments on an organic produce farm in Northern California, USA

Abstract

Shiga toxin-producing Escherichia coli (STECs) contamination of produce, as a result of contact with ruminant fecal material, has been associated with serious foodborne illness. Bacteriophages (phages) that infect STECs have primarily been reported to be of cattle origin. However, they likely exist in other environments or in animals that share habitats with cattle, such as goats. To explore the presence and diversity of phages specific to STEC O157 and the top six non-O157 STECs in goat-associated environments, environmental samples consisting of feces (goat and cattle) and soil samples were collected monthly for six months from an organic produce farm. A variety of phages belonging to the Myoviridae, Siphoviridae, and Podoviridae families were isolated from all goat fecal and half of the soil samples. The most commonly isolated phages belonged to Myoviridae and were lytic against STEC O103. The isolated phages had different host ranges, but collectively, showed lytic activity against O157 and the top six non-O157 STEC strains excluding O121. Two non-O157 STECs (O174: H21 and O-antigen-negative: H18) were isolated from soil and cattle feces, respectively. Although prior studies have reported that goats shed STEC into the environment, the findings of the current study suggest that goat feces may also contain lytic STEC-specific phages. The phages of goat origin have the capacity to infect STECs implicated in causing foodborne outbreaks, making them potential candidates for biocontrol pending additional characterization steps. Further work is needed to determine if the addition of goats to the farm environment could potentially reduce the presence of STECs.

Metagenomic investigation reveals bacteriophage-mediated horizontal transfer of antibiotic resistance genes in microbial communities of an organic agricultural ecosystem

“…Of these, three phage families, Myoviridae, Podoviridae, and Siphoviridae, were commonly detected in all animal fecal samples, with a relative abundance ranging from 0.1% to 3.4%. These trends are consistent with the results of previous studies showing that bacteriophages under families Myoviridae, Podoviridae, and Siphoviridae are known to occur ubiquitously in the fecal microbiomes of ruminant and non-ruminant farm animals, including poultry, cattle, pigs, goats, and sheep ( 30 , 31 ). Additionally, the families Inoviridae (60.26%) and Circoviridae (24.30%) were the most predominant in the goat and pig microbiomes, respectively.…”

Characterization of a T4-like Bacteriophage vB_EcoM-Sa45lw as a Potential Biocontrol Agent for Shiga Toxin-Producing Escherichia coli O45 Contaminated on Mung Bean Seeds

“…The phage was propagated with a fresh overnight bacterial culture of ATCC 13706 in 40 ml tryptic soy broth (TSB; Difco, Becton, Dickinson, Sparks, MD USA), supplemented with CaCl 2 at a final concentration of 10 mM, at 37°C for 24 h. Subsequently, the propagated phage was centrifuged at 8000 × g for 10 min, followed by filtration through a 0.22-μm filter membrane to remove bacterial debris before the experimental phage antimicrobial activity test(s). For TEM, proteomic analysis, and DNA extraction, the phage lysate was further concentrated via a 50 kDa cutoff Amicon Ultra-15 Centrifugal Filter Unit (Merck Millipore, Billerica, MA, USA) and purified by CsCl gradient ultracentrifugation as previously described ( 66 ).…”

Short Communication: The potency of lytic bacteriophage isolated from various environments to control the growth of Citrobacter braakii causing urinary tract infection

“…Supporting the present study, several earlier studies also found that phages originated from various animal farm wastes potentially have bacteriolytic activities against specific bacteria. Phage from goat farm waste was able to reduce shiga-toxin producing E. coli population (Lennon et al 2020). Phage isolated from wastewater collection tanks of various animal species also showed bacteriolytic activities against most common bacteria, including E. coli and Bacillus subtilis (Shukla and Hirpurkar 2011).…”