Inhibition of Bacterial Conjugation by Phage M13 and Its Protein g3p: Quantitative Analysis and Model

Abstract

Conjugation is the main mode of horizontal gene transfer that spreads antibiotic resistance among bacteria. Strategies for inhibiting conjugation may be useful for preserving the effectiveness of antibiotics and preventing the emergence of bacterial strains with multiple resistances. Filamentous bacteriophages were first observed to inhibit conjugation several decades ago. Here we investigate the mechanism of inhibition and find that the primary effect on conjugation is occlusion of the conjugative pilus by phage particles. This interaction is mediated primarily by phage coat protein g3p, and exogenous addition of the soluble fragment of g3p inhibited conjugation at low nanomolar concentrations. Our data are quantitatively consistent with a simple model in which association between the pili and phage particles or g3p prevents transmission of an F plasmid encoding tetracycline resistance. We also observe a decrease in the donor ability of infected cells, which is quantitatively consistent with a reduction in pili elaboration. Since many antibiotic-resistance factors confer susceptibility to phage infection through expression of conjugative pili (the receptor for filamentous phage), these results suggest that phage may be a source of soluble proteins that slow the spread of antibiotic resistance genes.

Engineering Modular Viral Scaffolds for Targeted Bacterial Population Editing

“…Traditional phage engineering strategies, such as in vitro manipulation, allele-exchange within bacterial hosts, and phage crossing via co-infection of bacteria (Beier et al, 1977; Garcia et al, 2003; Lin et al, 2011) have been used to modulate phage host range (Pouillot et al, 2010; Tetart et al, 1998; Trojet et al, 2011; Yoichi et al, 2005), but these strategies are inefficient and unable to achieve multiple genetic modifications in a single step. Screening for a desired mutation after classical crossing or recombination experiments can require PCR, restriction digestion, or plaque hybridization on hundreds of individual plaques, which are all costly and time-consuming methods.…”

Antihypertensives suppress the emergence of fluoroquinolone-resistant mutants in pneumococci: An in vitro study

“…(Lin et al, 2011). Fluoroquinolone resistance can be horizontally transmitted by plasmids in Gram-negative bacteria (Shaheen et al, 2013) or by recombination in streptococci (Duesberg et al, 2006;Pletz et al, 2005aPletz et al, , 2006b.…”

In-Vitro Study on Potential Efficacy of Acriflavine in the Prevention of Conjugational Transfer of Drug Resistance in Bacteria

“…15 Targeting similar relaxases, other compounds too have shown potential like EDTA and Sulbactomax. 16 There are also reports of certain Synthetic Fatty Acids 17 having selective inhibition of donors and Phage M13 18 which inhibit conjugation by other means. Acriflavine is a well-known DNA-intercalating agent which interferes with proper DNA propagation.…”