Bacterial Lysis through Interference with Peptidoglycan Synthesis Increases Biofilm Formation by Nontypeable Haemophilus influenzae

Martí, Sara; Puig, Carmen; Merlos, Alexandra; Viñas, Miguel; Jonge, Marien I. de; Liñares, Josefina; Ardanuy, Carmen; Langereis, Jeroen D.

doi:10.1128/msphere.00329-16

Cited by 19 publications

(15 citation statements)

References 29 publications

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“…In order to test this hypothesis further, we sequentially deleted each rpf gene to create a panel of mutants, none of which displayed any growth defects in broth. Hence, to further probe Rpf function, we tested the ability of rpf-defective mutants to form biofilms, given the demonstrated role of PG hydrolases to modulate biofilm formation/maturation in other bacteria (16,17,51). Assessment of the transcript levels of rpf genes in biofilms formed by the wild type after 7, 14, and 28 days revealed that rpfE2 and rpfE were highly expressed in biofilms.…”

Section: Discussionmentioning

confidence: 99%

Resuscitation-Promoting Factors Are Required for Mycobacterium smegmatis Biofilm Formation

Ealand

Rimal

Chang

et al. 2018

Appl Environ Microbiol

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Resuscitation-promoting factors (Rpfs) have previously been shown to act as growth-stimulatory molecules via their lysozyme-like activity on peptidoglycan in the bacterial cell wall. In this study, we investigated the ability of strains lacking genes to form biofilms and tested their susceptibilities to cell wall-targeting agents. contains four distinct homologues, namely, MSMEG_5700 (), MSMEG_5439 (), MSMEG_4640 (), and MSMEG_4643 (). During axenic growth of the wild-type strain, all four mRNA transcripts were expressed to various degrees, but the expression of MSMEG_4643 was significantly greater during exponential growth. Similarly, all mRNA transcripts could be detected in biofilms grown for 7, 14, and 28 days, with MSMEG_4643 expressed at the highest abundance after 7 days. In-frame unmarked deletion mutants (single and combinatorial) were generated and displayed altered colony morphologies and the inability to form typical biofilms. Moreover, any strain lacking and simultaneously exhibited increased susceptibility to rifampin, vancomycin, and SDS. Exogenous Rpf supplementation in the form of culture filtrate failed to restore biofilm formation. Liquid chromatography-mass spectrometry (LC-MS) analysis of peptidoglycan (PG) suggested a reduction in 4-3 cross-linked PG in the Δ mutant strain. In addition, the level of PG-repeat units terminating in 1,6-anhydroMurNAc appeared to be significantly reduced in the quadruple mutant. Collectively, our data have shown that Rpfs play an important role in biofilm formation, possibly through alterations in PG cross-linking and the production of signaling molecules. The cell wall of pathogenic mycobacteria is composed of peptidoglycan, arabinogalactan, mycolic acids, and an outer capsule. This inherent complexity renders it resistant to many antibiotics. Consequently, its biosynthesis and remodeling during growth directly impact viability. Resuscitation-promoting factors (Rpfs), enzymes with lytic transglycosylase activity, have been associated with the revival of dormant cells and subsequent resumption of vegetative growth. , a soil saprophyte and close relative of the human pathogen, encodes four distinct Rpfs. Herein, we assessed the relationship between Rpfs and biofilm formation, which is used as a model to study drug tolerance and bacterial signaling in mycobacteria. We demonstrated that progressive deletion of genes hampered the development of biofilms and reduced drug tolerance. These effects were accompanied by a reduction in muropeptide production and altered peptidoglycan cross-linking. Collectively, these observations point to an important role for Rpfs in mycobacterial communication and drug tolerance.

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Section: Discussionmentioning

confidence: 99%

Resuscitation-Promoting Factors Are Required for Mycobacterium smegmatis Biofilm Formation

Ealand

Rimal

Chang

et al. 2018

Appl Environ Microbiol

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“…HITS was also useful to identify H. influenzae genes required to colonize an influenza A virus (IAV) co-infection murine model, showing genes both exclusive or commonly shared by bacterial and IAV co-infection model systems [67] , or to screen genome-wide genetic interactions to unravel epistatic interaction accounting for H. influenzae survival in the murine lung [68] . Tn-seq suitability has also been reported for H. influenzae in vitro genome-wide screening studies including the identification of (i) essential genes [69] ; (ii) the carbonic anhydrase involvement in NTHi adaptation to changes in environmental CO 2 levels and intracellular survival [70] ; (iii) a role for the outer membrane protein P5 in NTHi survival to complement-mediated killing [71] , and for galactose-containing oligosaccharide structures in NTHi survival to complement-dependent neutrophil-mediated killing [72] ; (iv) the contribution of the mltC and lppB genes to biofilm formation [73] .…”

Section: Constantly Evolving Information From H Influenzae Whole Genome Sequencingmentioning

confidence: 99%

“…HITS* based in vivo genetic screenings [12] , [67] , [68] B2. Tn-seq based in vitro genetic screenings [69] , [70] , [71] , [72] , [73] C. Genome-wide gene expression profiling C1. Bacterial transcriptomic responses to changing environmental conditions [75] , [76] , [77] , [78] , [79] , [82] , [84] , [87] C2.…”

Section: Introductionmentioning

confidence: 99%

Learning from –omics strategies applied to uncover Haemophilus influenzae host-pathogen interactions: Current status and perspectives

López-López

Gil-Campillo

Díez-Martínez³

et al. 2021

Computational and Structural Biotechnology Journal

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Haemophilus influenzae has contributed to key bacterial genome sequencing hallmarks, as being not only the first bacterium to be genome-sequenced, but also starring the first genome-wide analysis of chromosomes directly transformed with DNA from a divergent genotype, and pioneering Tn-seq methodologies. Over the years, the phenomenal and constantly evolving development of –omic technologies applied to a whole range of biological questions of clinical relevance in the H. influenzae -host interplay, has greatly moved forward our understanding of this human-adapted pathogen, responsible for multiple acute and chronic infections of the respiratory tract. In this way, essential genes, virulence factors, pathoadaptive traits, and multi-layer gene expression regulatory networks with both genomic and epigenomic complexity levels are being elucidated. Likewise, the unstoppable increasing whole genome sequencing information underpinning H. influenzae great genomic plasticity, mainly when referring to non-capsulated strains, poses major challenges to understand the genomic basis of clinically relevant phenotypes and even more, to clearly highlight potential targets of clinical interest for diagnostic, therapeutic or vaccine development. We review here how genomic, transcriptomic, proteomic and metabolomic-based approaches are great contributors to our current understanding of the interactions between H. influenzae and the human airways, and point possible strategies to maximize their usefulness in the context of biomedical research and clinical needs on this human-adapted bacterial pathogen.

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“…Diverse classes of antimicrobials have been analyzed to determine their effects on bacterial physiology. For instance, beta-lactam antibiotics that inhibit cell wall biosynthesis have been found to increase biofilm formation, while antimicrobials such as fluoroquinolones targeting specific cellular functions like DNA replication may decrease formation (Marti et al, 2017; Ranieri et al, 2018; Yu et al, 2018). Likewise, some antimicrobials can alter bacterial cell surface properties such as ionic charge and cause more favorable conditions for adherence and biofilm formation (Kumar and Ting, 2013; Kumar and Anthony, 2016; Ranieri et al, 2018).…”

Section: Antimicrobials As a Weapon Or A Toolmentioning

confidence: 99%

Diversity, Ecology, and Prevalence of Antimicrobials in Nature

Mullis

Rambo²,

Baker³

et al. 2019

Front. Microbiol.

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Microorganisms possess a variety of survival mechanisms, including the production of antimicrobials that function to kill and/or inhibit the growth of competing microorganisms. Studies of antimicrobial production have largely been driven by the medical community in response to the rise in antibiotic-resistant microorganisms and have involved isolated pure cultures under artificial laboratory conditions neglecting the important ecological roles of these compounds. The search for new natural products has extended to biofilms, soil, oceans, coral reefs, and shallow coastal sediments; however, the marine deep subsurface biosphere may be an untapped repository for novel antimicrobial discovery. Uniquely, prokaryotic survival in energy-limited extreme environments force microbial populations to either adapt their metabolism to outcompete or produce novel antimicrobials that inhibit competition. For example, subsurface sediments could yield novel antimicrobial genes, while at the same time answering important ecological questions about the microbial community.

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Bacterial Lysis through Interference with Peptidoglycan Synthesis Increases Biofilm Formation by Nontypeable Haemophilus influenzae

Cited by 19 publications

References 29 publications

Resuscitation-Promoting Factors Are Required for Mycobacterium smegmatis Biofilm Formation

Resuscitation-Promoting Factors Are Required for Mycobacterium smegmatis Biofilm Formation

Learning from –omics strategies applied to uncover Haemophilus influenzae host-pathogen interactions: Current status and perspectives

Diversity, Ecology, and Prevalence of Antimicrobials in Nature

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