The interconnection between biofilm formation and horizontal gene transfer

The biofilm-associated protein (Bap) is a surface protein implicated in biofilm formation by Staphylococcus aureus isolated from chronic mastitis infections. The bap gene is carried in a putative composite transposon inserted in SaPIbov2, a mobile staphylococcal pathogenicity island. In this study, bap orthologue genes from several staphylococcal species, including Staphylococcus epidermidis, Staphylococcus chromogenes, Staphylococcus xylosus, Staphylococcus simulans and Staphylococcus hyicus, were identified, cloned and sequenced. Sequence analysis comparison of the bap gene from these species revealed a very high sequence similarity, suggesting the horizontal gene transfer of SaPIbov2 amongst them. However, sequence analyses of the flanking region revealed that the bap gene of these species was not contained in the SaPIbov2 pathogenicity island. Although they did not contain the icaADBC operon, all the coagulase-negative staphylococcal isolates harbouring bap were strong biofilm producers. Disruption of the bap gene in S. epidermidis abolished its capacity to form a biofilm, whereas heterologous complementation of a biofilm-negative strain of S. aureus with the Bap protein from S. epidermidis bestowed the capacity to form a biofilm on a polystyrene surface. Altogether, these results demonstrate that Bap orthologues from coagulase-negative staphylococci induce an alternative mechanism of biofilm formation that is independent of the PIA/PNAG exopolysaccharide.

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Dogs Leaving the ICU Carry a Very Large Multi-Drug Resistant Enterococcal Population with Capacity for Biofilm Formation and Horizontal Gene Transfer

PLoS ONE ◽

10.1371/journal.pone.0022451 ◽

2011 ◽

Vol 6 (7) ◽

pp. e22451 ◽

Cited By ~ 30

Author(s):

Anuradha Ghosh ◽

Scot E. Dowd ◽

Ludek Zurek

Keyword(s):

Gene Transfer ◽

Horizontal Gene Transfer ◽

Biofilm Formation ◽

Drug Resistant

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Safety of Food and Water Supplies in the Landscape of Changing Climate

Microorganisms ◽

10.3390/microorganisms7100469 ◽

2019 ◽

Vol 7 (10) ◽

pp. 469 ◽

Cited By ~ 4

Author(s):

Aliyar Cyrus Fouladkhah ◽

Brian Thompson ◽

Janey Smith Camp

Keyword(s):

Gene Transfer ◽

Horizontal Gene Transfer ◽

Quorum Sensing ◽

Microbial Communities ◽

Biofilm Formation ◽

Processing Conditions ◽

Water Supplies ◽

Changing Climate ◽

Transfer Mechanisms

In response to evolving environmental, production, and processing conditions, microbial communities have tremendous abilities to move toward increased diversity and fitness by various pathways such as vertical and horizontal gene transfer mechanisms, biofilm formation, and quorum sensing [...]

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Potential Risk of Spreading Resistance Genes within Extracellular-DNA-Dependent Biofilms of Streptococcus mutans in Response to Cell Envelope Stress Induced by Sub-MICs of Bacitracin

Applied and Environmental Microbiology ◽

10.1128/aem.00770-20 ◽

2020 ◽

Vol 86 (16) ◽

Author(s):

Ryo Nagasawa ◽

Tsutomu Sato ◽

Nobuhiko Nomura ◽

Tomoyo Nakamura ◽

Hidenobu Senpuku

Keyword(s):

Cell Wall ◽

Gene Transfer ◽

Horizontal Gene Transfer ◽

Biofilm Formation ◽

Cell Envelope ◽

Resistant Bacteria ◽

Drug Resistant ◽

Content Type ◽

Drug Resistant Bacteria ◽

Envelope Stress

ABSTRACT Antibiotics are used to treat or prevent some types of bacterial infection. The inappropriate use of antibiotics unnecessarily promotes antibiotic resistance and increases resistant bacteria, and controlling these bacteria is difficult. While the emergence of drug-resistant bacteria is a serious problem, the behavior of drug-resistant bacteria is not fully understood. In this study, we investigated the behavior of Streptococcus mutans, a major etiological agent of dental caries that is resistant to bacitracin, which is a cell wall-targeting antibiotic, and focused on biofilm formation in the presence of bacitracin. S. mutans UA159 most strongly induced extracellular DNA (eDNA)-dependent biofilm formation in the presence of bacitracin at 1/8× MIC. The ΔmbrC and ΔmbrD mutant strains, which lack bacitracin resistance, also formed biofilms in the presence of bacitracin at 1/2× MIC. This difference between the wild type and the mutants was caused by the induction of atlA expression in the mid-log phase. We also revealed that certain rgp genes involved in the synthesis of rhamnose-glucose polysaccharide related to cell wall synthesis were downregulated by bacitracin. In addition, glucosyltransferase-I was also involved in eDNA-dependent biofilm formation. The biofilm led to increased transformation efficiencies and promoted horizontal gene transfer. Biofilms were also induced by ampicillin and vancomycin, antibiotics targeting cell wall synthesis, suggesting that cell envelope stress triggers biofilm formation. Therefore, the expression of the atlA and rgp genes is regulated by S. mutans, which forms eDNA-dependent biofilms, promoting horizontal gene transfer in response to cell envelope stress induced by sub-MICs of antibiotics. IMPORTANCE Antibiotics have been reported to induce biofilm formation in many bacteria at subinhibitory concentrations. Accordingly, it is conceivable that the MIC against drug-sensitive bacteria may promote biofilm formation of resistant bacteria. Since drug-resistant bacteria have spread, it is important to understand the behavior of resistant bacteria. Streptococcus mutans is bacitracin resistant, and the 1/8× MIC of bacitracin, which is a cell wall-targeted antibiotic, induced eDNA-dependent biofilm formation. The ΔmbrC and ΔmbrD strains, which are not resistant to bacitracin, also formed biofilms in the presence of bacitracin at 1/2× MIC, and biofilms of both the wild type and mutants promoted horizontal gene transfer. Another cell wall-targeted antibiotic, vancomycin, showed effects on biofilms and gene transfer similar to those of bacitracin. Thus, treatment with cell wall-targeted antibiotics may promote the spread of drug-resistant genes in biofilms. Therefore, the behavior of resistant bacteria in the presence of antibiotics at sub-MICs should be investigated when using antibiotics.

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Biofilm Formation Drives Transfer of the Conjugative Element ICEBs1inBacillus subtilis

mSphere ◽

10.1128/msphere.00473-18 ◽

2018 ◽

Vol 3 (5) ◽

Cited By ~ 10

Author(s):

Frédéric Lécuyer ◽

Jean-Sébastien Bourassa ◽

Martin Gélinas ◽

Vincent Charron-Lamoureux ◽

Vincent Burrus ◽

...

Keyword(s):

Extracellular Matrix ◽

Antibiotic Resistance ◽

Gene Transfer ◽

Horizontal Gene Transfer ◽

Biofilm Formation ◽

Bacterial Species ◽

High Rate ◽

Conjugative Transfer ◽

Bacterial Strains ◽

Content Type

ABSTRACTHorizontal gene transfer by integrative and conjugative elements (ICEs) is a very important mechanism for spreading antibiotic resistance in various bacterial species. In environmental and clinical settings, most bacteria form biofilms as a way to protect themselves against extracellular stress. However, much remains to be known about ICE transfer in biofilms. Using ICEBs1fromBacillus subtilis, we show that the natural conjugation efficiency of this ICE is greatly affected by the ability of the donor and recipient to form a biofilm. ICEBs1transfer considerably increases in biofilm, even at low donor/recipient ratios. Also, while there is a clear temporal correlation between biofilm formation and ICEBs1transfer, biofilms do not alter the level of ICEBs1excision in donor cells. Conjugative transfer appears to be favored by the biophysical context of biofilms. Indeed, extracellular matrix production, particularly from the recipient cells, is essential for biofilms to promote ICEBs1transfer. Our study provides basic new knowledge on the high rate of conjugative transfer of ICEs in biofilms, a widely preponderant bacterial lifestyle in the environment, which could have a major impact on our understanding of horizontal gene transfer in natural and clinical environments.IMPORTANCETransfer of mobile genetic elements from one bacterium to another is the principal cause of the spread of antibiotic resistance. However, the dissemination of these elements in environmental contexts is poorly understood. In clinical and environmental settings, bacteria are often found living in multicellular communities encased in a matrix, a structure known as a biofilm. In this study, we examined how forming a biofilm influences the transmission of an integrative and conjugative element (ICE). Using the model Gram-positive bacteriumB. subtilis, we observed that biofilm formation highly favors ICE transfer. This increase in conjugative transfer is due to the production of extracellular matrix, which creates an ideal biophysical context. Our study provides important insights into the role of the biofilm structure in driving conjugative transfer, which is of major importance since biofilm is a widely preponderant bacterial lifestyle for clinically relevant bacterial strains.

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