The highly evolvable nature of the antibiotic efflux protein TolC limits use of phages and bacterial toxins as antibacterial agents

Abstract

Bacteriophages and bacterial toxins are promising antibacterials to treat infections caused by multidrug resistant (MDR) bacteria. Bacteriophages have recently been successfully used to treat life-threatening infections caused by MDR bacteria [1-3]. One potential problem with using these antibacterial agents is the evolution of resistance against them. Here, we studied the fitness landscape of the Escherichia coli TolC protein, an outer membrane protein that is exploited by a pore forming toxin called colicin E1 and by TLS, a lytic bacteriophage [4, 5]. By systematically assessing the distribution of fitness effects (DFEs) of ~9,000 single amino acid replacements in TolC using either positive (antibiotics and bile salts) or negative (colicin E1 and TLS-phage) selection pressures, we quantified evolvability of the TolC. We demonstrated that the TolC is highly optimized for the efflux of antibiotics and bile salts. In contrast, under colicin E1 and TLS phage selection, TolC sequence is very sensitive to mutation. Our findings suggest that TolC is a highly evolvable target limiting the potential clinical use of bacteriophages and bacterial toxins.

Multidrug resistance pumps as a keystone of bacterial resistance

“…Об эволюционной консервативности помп свидетельствует повсеместное распространение помп семейств MFS и RND как среди прокариот (включая бактерий и архей), так и среди эукариот [41,42], поэтому консервативность помп в пределах одного вида не удивительна [43]. Это также подтверждается тем фактом, что структуры помп выбирались бактериофагами в качестве мишеней для своего связывания [44,45]. Способность обеспечивать отток лекарств, по-видимому, появлялась всего несколько раз в ходе эволюции и стабильно сохранялась, но при этом модуляция специфичности субстрата этих систем происходила неоднократно [46].…”

Effect Of Avocado Seed (Persea Americana Mill.) On The Growth Of Bacteria Prevotella Intermedia (In Vitro)

“…Prevotella intermedia has the ability to produce beta-lactamase enzymes so that it can create resistance to beta-lactane antibiotics, such as penicillin [4]. Beta-lactams are the first-choice class of antibiotics used to treat oral infections [5]. Previous studies have proven that more than half of the Prevotella intermedia bacterial isolates are resistant to penicillin, which is a beta-lactam class of antibiotics [5].…”

“…Beta-lactams are the first-choice class of antibiotics used to treat oral infections [5]. Previous studies have proven that more than half of the Prevotella intermedia bacterial isolates are resistant to penicillin, which is a beta-lactam class of antibiotics [5]. The existence of antibiotic resistance raises concerns that it requires other alternatives that have the potential to kill or inhibit the growth of bacteria, one of which is using avocado seeds.…”

Characterization of ColE1 Production for Robust tolC Plate Dual-Selection in E. coli

“…We are currently unaware of any commercially available sources. Published purification methods 20,21 employ fractionation and multiple chromatography steps for protein purification. In addition, the tolC system has been primarily used in liquid selections, complicating the isolation of single colonies.…”

“…Gregg et al 13 described a plate-based tolC selection scheme using cell lysate for isolation of single colonies from specific recombineering strains. Recently, Tamer et al 21 described an alternate purification method employing a customized expression vector and both size-exclusion and cation chromatography.…”