Bacteriocin Occurrence and Activity in Escherichia coli Isolated from Bovines and Wastewater

Abstract

The increasing prevalence of antimicrobial resistant (AMR) E. coli and related Enterobacteriaceae is a serious problem necessitating new mitigation strategies and antimicrobial agents. Bacteriocins, functionally diverse toxins produced by most microbes, have long been studied for their antimicrobial potential. Bacteriocins have once again received attention for their role as probiotic traits that could mitigate pathogen burden and AMR bacteria in livestock. Here, bacteriocins were identified by activity screening and whole-genome sequencing of bacteriocin-producers capable of inhibiting bovine and wastewater E. coli isolates enriched for resistance to cephalosporins. Producers were tested for activity against shiga toxin-producing E. coli (STEC), AMR E. coli, and related enteric pathogens. Multiple bacteriocins were found in 14 out of 90 E. coli isolates tested. Based on alignment within BACTIBASE, colicins M, B, R, Ia, Ib, S4, E1, E2, and microcins V, J25, and H47, encoded by identical, variant, or truncated genes were identified. Although some bacteriocin-producers exhibited activity against AMR and STEC E. coli in agar-based assays, most did not. Despite this idiosyncrasy, liquid co-cultures of all bacteriocinogenic isolates with luciferase-expressing generic (K12) or STEC E. coli (EDL933) resulted in inhibited growth or reduced viability. These abundant toxins may have real potential as next-generation control strategies in livestock production systems but separating the bacteriocin from its immunity gene may be necessary for such a strategy to be effective.

Bacteriocins, Potent Antimicrobial Peptides and the Fight against Multi Drug Resistant Species: Resistance Is Futile?

“…The outer membrane of Gram-negative species protects them from bacteriocins produced by Gram-positive species. Under stress conditions, however, such as acidic pH, temperature variations, presence of chelators, absence of metal ions and high saline environments, certain Gram-negative species including E. coli [34] and Salmonella become sensitive to Gram-positive bacteriocins [6].…”

High-Zinc Supplementation of Weaned Piglets Affects Frequencies of Virulence and Bacteriocin Associated Genes Among Intestinal Escherichia coli Populations

“…Since bacteriocins promote the producing bacterial cells while competing for resources in a distinct ecological niche with other E. coli strains and closely related bacteria, they probably play an important role in structuring microbial communities residing in the gut (83). In addition, activity of particular bacteriocin-producing E. coli toward competing bacteria, e.g., STEC O157:H7, has been reported (84,85). This led us to investigate if HZG-E. coli and/or those isolates associated with the 512 µg/ml ZnCl 2 MIC harbor either more BAGs or a certain BAG pattern (Figure 1, Table 3).…”

Mining, heterologous expression, purification, antibactericidal mechanism, and application of bacteriocins: A review

“…In addition, E. coli selectively cultured from bovine feces and wastewater with properties inhibiting MG1655 or EDL933 were whole‐genome sequenced. Followed by alignment with 230 bacteriocins in BACTIBASE database, identical, variant, or truncated genes (colicins M, B, R, Ia, Ib, S4, E1, and E2 and microcins V, J25, and H47) were identified (Cameron et al., 2019). Certainly, both BACTIBASE and BAGEL had very good performance to identify antimicrobial peptides (AMPs) and non‐AMP peptides, which were separated into antimicrobial, antibacterial, and bacteriocins (Gabere & Noble, 2017).…”