Direct stimulation of the transfer of antibiotic resistance by sex pheromones in Streptococcus faecalis

doi:10.1016/0147-619X(81)90035-4

Plasmid

Volume 6, Issue 3, November 1981, Pages 270-278

https://doi.org/10.1016/0147-619X(81)90035-4 Get rights and content

Abstract

Clinical isolates of Streptococcus faecalis were examined for plasmid content and plasmid-related traits in order to determine whether such strains carried conjugative antibiotic resistance plasmids whose transfer was stimulated by sex pheromones. A 35-Mdalton tetracycline-resistance plasmid called pCF-10 was identified. pCF-10 carries genes that enable its host cell to clump and to act as a highly effective donor when exposed to sex pheromone preparations from recipients. The genetic background of the host cell markedly affects the expression of the pCF-10 fertility functions. The properties of this plasmid make it a good candidate for a detailed genetic analysis of streptococcal conjugation.

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Electron microscope heteroduplex methods for mapping regions of base sequence homology in nucleic acids
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Plasmid transfer in Streptococcus faecalis: Production of multiple sex pheromones by recipients
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Plasmids mediating multiple drug resistance in group B streptococcus: Transferability and molecular properties
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Streptozotocin, an antibiotic superior to penicillin in the selection of rare bacterial mutations
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Conjugal transfer of plasmids determining resistance to macrolides, lincosamides, and streptogramin-B type antibiotics among group A, B, D, and H streptococci
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Identification and characterization of large plasmids in Rhizobium meliloti using agarose gel electrophoresis
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Induced cell aggregation and mating in Streptococcus faecalis: Evidence for a bacterial sex pheromone

There are more references available in the full text version of this article.

Cited by (84)

Pheromone effect of estradiol regulates the conjugative transfer of pCF10 carrying antibiotic resistance genes
2023, Journal of Hazardous Materials
Horizontal gene transfer (HGT) mediated by conjugative plasmids greatly contributes to bacteria evolution and the transmission of antibiotic resistance genes (ARGs). In addition to the selective pressure imposed by extensive antibiotic use, environmental chemical pollutants facilitate the dissemination of antibiotic resistance, consequently posing a serious threat to the ecological environment. Presently, the majority of studies focus on the effects of environmental compounds on R plasmid-mediated conjugation transfer, and pheromone-inducible conjugation has largely been neglected. In this study, we explored the pheromone effect and potential molecular mechanisms of estradiol in promoting the conjugative transfer of pCF10 plasmid in Enterococcus faecalis. Environmentally relevant concentrations of estradiol significantly increased the conjugative transfer of pCF10 with a maximum frequency of 3.2 × 10^-2, up to 3.5-fold change compared to that of control. Exposure to estradiol induced the activation of pheromone signaling cascade by increasing the expression of ccfA. Furthermore, estradiol might directly bind to the pheromone receptor PrgZ and promote pCF10 induction and finally enhance the conjugative transfer of pCF10. These findings cast valuable insights on the roles of estradiol and its homolog in increasing antibiotic resistance and the potential ecological risk.
Structure of the enterococcal T4SS protein PrgL reveals unique dimerization interface in the VirB8 protein family
2022, Structure
Citation Excerpt :
E. coli TOP10 was used for cloning. L. lactis NZ9000 was used for protein production (Linares et al., 2010), E. faecalis OG1RF was used as donor cells for in vivo studies (Dunny et al., 1981), and E. faecalis OG1ES was used as recipient cells (Staddon et al., 2006). Cells were grown and the protein purified as described in method details.
Multidrug-resistant bacteria pose serious problems in hospital-acquired infections (HAIs). Most antibiotic resistance genes are acquired via conjugative gene transfer, mediated by type 4 secretion systems (T4SS). Although most multidrug-resistant bacteria responsible for HAIs are of Gram-positive origin, with enterococci being major contributors, mostly Gram-negative T4SSs have been characterized. Here, we describe the structure and organization of PrgL, a core protein of the T4SS channel, encoded by the pCF10 plasmid from Enterococcus faecalis. The structure of PrgL displays similarity to VirB8 proteins of Gram-negative T4SSs. In vitro experiments show that the soluble domain alone is enough to drive both dimerization and dodecamerization, with a dimerization interface that differs from all other known VirB8-like proteins. In vivo experiments verify the importance of PrgL dimerization. Our findings provide insight into the molecular building blocks of Gram-positive T4SS, highlighting similarities but also unique features in PrgL compared to other VirB8-like proteins.
Enterococcal PrgA Extends Far Outside the Cell and Provides Surface Exclusion to Protect against Unwanted Conjugation
2020, Journal of Molecular Biology
Horizontal gene transfer between Gram-positive bacteria leads to a rapid spread of virulence factors and antibiotic resistance. This transfer is often facilitated via type 4 secretion systems (T4SS), which frequently are encoded on conjugative plasmids. However, donor cells that already contain a particular conjugative plasmid resist acquisition of a second copy of said plasmid. They utilize different mechanisms, including surface exclusion for this purpose. Enterococcus faecalis PrgA, encoded by the conjugative plasmid pCF10, is a surface protein that has been implicated to play a role in both virulence and surface exclusion, but the mechanism by which this is achieved has not been fully explained. Here, we report the structure of full-length PrgA, which shows that PrgA protrudes far out from the cell wall (approximately 40 nm), where it presents a protease domain. In vivo experiments show that PrgA provides a physical barrier to cellular adhesion, thereby reducing cellular aggregation. This function of PrgA contributes to surface exclusion, reducing the uptake of its cognate plasmid by approximately one order of magnitude. Using variants of PrgA with mutations in the catalytic site we show that the surface exclusion effect is dependent on the activity of the protease domain of PrgA. In silico analysis suggests that PrgA can interact with another enterococcal adhesin, PrgB, and that these two proteins have co-evolved. PrgB is a strong virulence factor, and PrgA is involved in post-translational processing of PrgB. Finally, competition mating experiments show that PrgA provides a significant fitness advantage to plasmid-carrying cells.
CRISPR-Cas and restriction-modification act additively against conjugative antibiotic resistance plasmid transfer in Enterococcus faecalis
2016, mSphere
Enterococcus faecalis is a bacterium that normally inhabits the gastrointestinal tracts of humans and other animals. Although these bacteria are members of our native gut flora, they can cause life-threatening infections in hospitalized patients. Antibiotic resistance genes appear to be readily shared among high-risk E. faecalis strains, and multidrug resistance in these bacteria limits treatment options for infections. Here, we find that CRISPR-Cas and restriction-modification systems, which function as adaptive and innate immune systems in bacteria, significantly impact the spread of antibiotic resistance genes in E. faecalis populations. The loss of these systems in high-risk E. faecalis suggests that they are immunocompromised, a tradeoff that allows them to readily acquire new genes and adapt to new antibiotics.
Enterococcus faecalis is an opportunistic pathogen and a leading cause of nosocomial infections. Conjugative pheromone-responsive plasmids are narrow-host-range mobile genetic elements (MGEs) that are rapid disseminators of antibiotic resistance in the faecalis species. Clustered regularly interspaced short palindromic repeat (CRISPR)-Cas and restriction-modification confer acquired and innate immunity, respectively, against MGE acquisition in bacteria. Most multidrug-resistant E. faecalis isolates lack CRISPR-Cas and possess an orphan locus lacking cas genes, CRISPR2, that is of unknown function. Little is known about restriction-modification defense in E. faecalis. Here, we explore the hypothesis that multidrug-resistant E. faecalis strains are immunocompromised. We assessed MGE acquisition by E. faecalis T11, a strain closely related to the multidrug-resistant hospital isolate V583 but which lacks the ~620 kb of horizontally acquired genome content that characterizes V583. T11 possesses the E. faecalis CRISPR3-cas locus and a predicted restriction-modification system, neither of which occurs in V583. We demonstrate that CRISPR-Cas and restriction-modification together confer a 4-log reduction in acquisition of the pheromone-responsive plasmid pAM714 in biofilm matings. Additionally, we show that the orphan CRISPR2 locus is functional for genome defense against another pheromone-responsive plasmid, pCF10, only in the presence of cas9 derived from the E. faecalis CRISPR1-cas locus, which most multidrug-resistant E. faecalis isolates lack. Overall, our work demonstrated that the loss of only two loci led to a dramatic reduction in genome defense against a clinically relevant MGE, highlighting the critical importance of the E. faecalis accessory genome in modulating horizontal gene transfer. Our results rationalize the development of antimicrobial strategies that capitalize upon the immunocompromised status of multidrug-resistant E. faecalis.
IMPORTANCE Enterococcus faecalis is a bacterium that normally inhabits the gastrointestinal tracts of humans and other animals. Although these bacteria are members of our native gut flora, they can cause life-threatening infections in hospitalized patients. Antibiotic resistance genes appear to be readily shared among high-risk E. faecalis strains, and multidrug resistance in these bacteria limits treatment options for infections. Here, we find that CRISPR-Cas and restriction-modification systems, which function as adaptive and innate immune systems in bacteria, significantly impact the spread of antibiotic resistance genes in E. faecalis populations. The loss of these systems in high-risk E. faecalis suggests that they are immunocompromised, a tradeoff that allows them to readily acquire new genes and adapt to new antibiotics.
Modeling of gene regulatory processes by population-mediated signaling: New applications of population balances
2012, Chemical Engineering Science
Citation Excerpt :
The importance of this formulation is demonstrated by including a calculation that dispels the notion established in the literature that when bistability exists in gene expression bimodal distributions of protein levels would result. We are concerned with a gene regulatory process connected with the transfer of drug resistance in Enterococcus faecalis (Dunny et al., 1981) induced by a molecule called cCF10, pheromone, released by a population of recipient cells. The actual transfer of drug resistance occurs as a result of conjugation between the so-called donor cells (containing plasmids referred to as pCF10 on which genes encode drug resistance) and recipient cells not resistant to the drug.
Population balance modeling is considered for cell populations in gene regulatory processes in which one or more intracellular variables undergo stochastic dynamics as determined by Ito stochastic differential equations. This paper addresses formulation and computational issues with sample applications to the spread of drug resistance among bacterial cells. It is shown that predictions from population balances can display qualitative differences from those made with single cell models which are usually encountered in the literature. Such differences are deemed to be important.
A novel conjugative plasmid from Enterococcus faecalis E99 enhances resistance to ultraviolet radiation
2010, Plasmid
Enterococcus faecalis has emerged as a prominent healthcare-associated pathogen frequently encountered in bacteremia, endocarditis, urinary tract infection, and as a leading cause of antibiotic-resistant infections. We recently demonstrated a capacity for high-level biofilm formation by a clinical E. faecalis isolate, E99. This high biofilm-forming phenotype was attributable to a novel locus, designated bee, specifying a pilus at the bacterial cell surface and localized to a large ∼80 kb conjugative plasmid. To better understand the origin of the bee locus, as well as to potentially identify additional factors important to the biology and pathogenesis of strain E99, we sequenced the entire plasmid. The nucleotide sequence of the plasmid, designated pBEE99, revealed large regions of identity to the previously characterized conjugative plasmid pCF10. In addition to the bee locus, pBEE99 possesses an open reading frame potentially encoding aggregation substance, as well as open reading frames putatively encoding polypeptides with 60% to 99% identity at the amino acid level to proteins involved in regulation of the pheromone response and conjugal transfer of pCF10. However, strain E99 did not respond to the cCF10 pheromone in clumping assays. While pBEE99 was found to be devoid of any readily recognizable antibiotic resistance determinants, it carries two non-identical impB/mucB/samB-type genes, as well as genes potentially encoding a two-component bacteriocin similar to that encoded on pYI14. Although no bacteriocin activity was detected from an OG1RF transconjugant carrying pBEE99 against strain FA2–2, it was approximately an order of magnitude more resistant to ultraviolet radiation. Moreover, curing strain E99 of this plasmid significantly reduced its ability to survive UV exposure. Therefore, pBEE99 represents a novel conjugative plasmid that confers biofilm-forming and enhanced UV resistance traits that might potentially impact the virulence and/or fitness of E. faecalis.

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Plasmid

Abstract

References (18)

Electron microscope heteroduplex methods for mapping regions of base sequence homology in nucleic acids

Plasmid transfer in Streptococcus faecalis: Production of multiple sex pheromones by recipients

Plasmid

Plasmids mediating multiple drug resistance in group B streptococcus: Transferability and molecular properties

Plasmid

Streptozotocin, an antibiotic superior to penicillin in the selection of rare bacterial mutations

FEMS Microbiol. Lett

Conjugal transfer of plasmids determining resistance to macrolides, lincosamides, and streptogramin-B type antibiotics among group A, B, D, and H streptococci

FEMS Microbiol. Lett

Identification and characterization of large plasmids in Rhizobium meliloti using agarose gel electrophoresis

J. Gen. Microbiol

Characterization of three plasmid deoxyribonucleic acid molecules in a strain of Streptococcus faecalis: Identification of a plasmid determining erythromycin resistance

J. Bacteriol

Transmissible toxin (hemolysin) plasmid in Streptococcus faecalis and its mobilization of a non-infectious drug resistance plasmid

J. Bacteriol

Induced cell aggregation and mating in Streptococcus faecalis: Evidence for a bacterial sex pheromone

Cited by (84)

Pheromone effect of estradiol regulates the conjugative transfer of pCF10 carrying antibiotic resistance genes

Structure of the enterococcal T4SS protein PrgL reveals unique dimerization interface in the VirB8 protein family

Enterococcal PrgA Extends Far Outside the Cell and Provides Surface Exclusion to Protect against Unwanted Conjugation

CRISPR-Cas and restriction-modification act additively against conjugative antibiotic resistance plasmid transfer in Enterococcus faecalis

Modeling of gene regulatory processes by population-mediated signaling: New applications of population balances

A novel conjugative plasmid from Enterococcus faecalis E99 enhances resistance to ultraviolet radiation

Regular articleDirect stimulation of the transfer of antibiotic resistance by sex pheromones in Streptococcus faecalis

Abstract

Plasmid

Plasmid

FEMS Microbiol. Lett

FEMS Microbiol. Lett

Identification and characterization of large plasmids in Rhizobium meliloti using agarose gel electrophoresis

J. Gen. Microbiol

Characterization of three plasmid deoxyribonucleic acid molecules in a strain of Streptococcus faecalis: Identification of a plasmid determining erythromycin resistance

J. Bacteriol

Transmissible toxin (hemolysin) plasmid in Streptococcus faecalis and its mobilization of a non-infectious drug resistance plasmid

J. Bacteriol

Induced cell aggregation and mating in Streptococcus faecalis: Evidence for a bacterial sex pheromone

Regular article
Direct stimulation of the transfer of antibiotic resistance by sex pheromones in Streptococcus faecalis