Prospects of antiquorum substances as an alternative to antibiotic therapy in animal husbandry (review)

Frequent and inappropriate use of antibiotics in animal husbandry threatens to expand the spectrum of antibiotic-resistant bacteria. Quorum sensing (QS) is one of the mechanisms responsible for this process. For its implementation, bacteria use autoinducers, the special signaling molecules for information exchange (A.A. Miller et al., 2011). The studies to give insight of this mechanism have shed light on the existence of substances that act as Quorum sensing inhibitors (quorum suppressors) (B. Remy et al., 2018), which made such studies even more relevant (J. Bzdreng et al., 2017). In our review, we have summarized the latest data on the search and development of the biologically active compounds that can become an alternative to antibiotic drugs used in animal husbandry. These include bacterial enzymes (AGL-lactonases, AGL-acylases, decarboxylases, and deaminases) that can degrade quorum sensing signal autoinducers (V.C. Kalia et al., 2011), as well as a-amylases, b-glucanases, lipases, and proteases involved in the destruction of biofilms (R. Sharma et al., 2001). The antimicrobial properties are also characteristic of animal enzymes acylase I (D. Paul et al., 2010), paraoxonase (J.F. Teiber et al., 2008), and lactonase, plant enzymes laccase (R. Al-Hussaini et al., 2009), alliinase, thiol-dependent enzyme and lactonase derived from garlic and medicinal plants (A. Adonizio et al., 2008), enzymes of marine organisms, particularly bromoperoxidase of the algae Laminaria digitata , alginate lyases from algae, invertebrates, and marine microorganisms, and halogenated furanones of Delisea pulchra (S.A. Borchardt et al., 2001; M. Mane-field et al., 2000). In addition, we can distinguish antimicrobial digestive enzymes used as feed additives, e.g., phytase (O. Adeola et al., 2011), xylanase and lysozyme (G. Cheng et al., 2014). Studies of phytobiotics and essential oils as quorum sensing inhibitors are promising (V.I. Fisinin et al., 2018). Their inhibitory ability is shown due to the similarity of the chemical structures of some plant extracts to the structure of acyl-homoserine-lactone and inactivation of signaling molecules (R. Chevrot et al., 2006; F. Nazzaro et al., 2013). Another prospective alternative is the use of antimicrobial combinatins enabling a synergistic effect due to the variety of mechanisms of overcoming the recurrent bacterial communications and destroying persistent bacterial cells. These polypeptide cocktails may include the combination of antibiotics with natural compounds. The amtimicrobial efficacy has shown for combination of tobramycin and some plant extracts, partilularly cinnamaldehyde and baykalin hydrate against Burkholderia cenocepacia and Pseudomonas aeruginos (G. Brackman et al., 2011), a wide range of antibiotics, e.g., aminoglycosides (T.H. Jakobsen et al., 2012; M. Stenvang et al., 2016), quinolones (Q. Guo et al., 2016), polypeptide antibiotics (A. Furiga et al., 2016; Z.P. Bulman et al., 2017), cephalosporins and glycopeptides (D. Maura et al., 2017), and various quorum sensing inhibitors.