From environmental signals to regulators: Modulation of biofilm development in Gram-positive bacteria

2014 ◽  
Vol 54 (7) ◽  
pp. 616-632 ◽  
Author(s):  
Eisha Mhatre ◽  
Ramses Gallegos Monterrosa ◽  
Ákos T. Kovács
Keyword(s):  
Gram Positive ◽  
Environmental Signals ◽  
Gram Positive Bacteria ◽  
Biofilm Development

scholarly journals A Pilot Study of Bacteriological Population Changes through Potable Water Treatment and Distribution

2000 ◽  
Vol 66 (1) ◽  
pp. 268-276 ◽  
Author(s):  
Cheryl D. Norton ◽  
Mark W. LeChevallier
Keyword(s):  
Pilot Study ◽  
Biologically Active ◽  
Plate Count ◽  
Identification System ◽  
Population Changes ◽  
Gram Positive ◽  
Pipe Surface ◽  
Treated Water ◽  
Gram Positive Bacteria ◽  
Biofilm Development

ABSTRACT This pilot study compares the compositions of bacterial biofilms in pipe networks supplied with water containing either high levels of biodegradable organic matter (BOM) or low levels of BOM (conventionally or biologically treated, respectively). The Microbial Identification System for fatty acid analysis was utilized in this study to identify a large number of organisms (>1,400) to determine population changes in both conventionally and biologically treated water and biofilms. Data generated during this study indicated that suspended bacteria have little impact on biofilms, and despite treatment (conventional or biological), suspended microbial populations were similar following disinfection. Prechlorination with free chlorine resulted not only in reduced plate count values but also in a dramatic shift in the composition of the bacterial population to predominately gram-positive bacteria. Chlorination of biologically treated water produced the same shifts toward gram-positive bacteria. Removal of assimilable organic carbon by the biologically active filters slowed the rate of biofilm accumulation, but biofilm levels were similar to those found in conventionally treated water within several weeks. Iron pipes stimulated the rate of biofilm development, and bacterial levels on disinfected iron pipes exceeded those for chlorinated polyvinyl chloride pipes. The study showed that the iron pipe surface dramatically influenced the composition, activity, and disinfection resistance of biofilm bacteria.

scholarly journals Pili in Gram-positive bacteria: assembly, involvement in colonization and biofilm development

2008 ◽  
Vol 16 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Anjali Mandlik ◽  
Arlene Swierczynski ◽  
Asis Das ◽  
Hung Ton-That
Keyword(s):  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Biofilm Development

scholarly journals Regulation of d-Alanyl-Lipoteichoic Acid Biosynthesis in Streptococcus agalactiae Involves a Novel Two-Component Regulatory System

2001 ◽  
Vol 183 (21) ◽  
pp. 6324-6334 ◽  
Author(s):  
Claire Poyart ◽  
Marie Cécile Lamy ◽  
Claire Boumaila ◽  
Franz Fiedler ◽  
Patrick Trieu-Cuot
Keyword(s):  
Amino Acid ◽  
Streptococcus Agalactiae ◽  
Response Regulator ◽  
Regulatory System ◽  
Lipoteichoic Acid ◽  
Kanamycin Resistance ◽  
Gram Positive ◽  
Environmental Signals ◽  
Gram Positive Bacteria ◽  
Insertional Inactivation

ABSTRACT The dlt operon of gram-positive bacteria comprises four genes (dltA, dltB, dltC, and dltD) that catalyze the incorporation of d-alanine residues into the lipoteichoic acids (LTAs). In this work, we characterized thedlt operon of Streptococcus agalactiae, which, in addition to the dltA to dltD genes, included two regulatory genes, designated dltR and dltS, located upstream of dltA. The dltR gene encodes a 224-amino-acid putative response regulator belonging to the OmpR family of regulatory proteins. The dltS gene codes for a 395-amino-acid putative histidine kinase thought to be involved in the sensing of environmental signals. The dlt operon ofS. agalactiae is mainly transcribed from the P dltR promoter, which directs synthesis of a 6.5-kb transcript encompassing dltR, dltS, dltA, dltB, dltC, and dltD, and from a weaker promoter, P dltA , which is located in the 3′ extremity ofdltS. We demonstrate that P dltR , but not P dlA , is activated by DltR in the presence of DltS in d-Ala-deficient LTA mutants resulting from insertional inactivation of the dltA gene, which encodes the cytoplasmic d-alanine-d-alanyl carrier ligase DltA. Expression of the dlt operon does not require DltR and DltS, since the basal activity of P dltR is high, being 20-fold that of the constitutive promoter P aphA-3 which directs synthesis of the kanamycin resistance gene aphA-3 in various gram-positive bacteria. We hypothesize that the role of DltR and DltS in the control of expression of the dlt operon is to maintain the level of d-Ala esters in LTAs at a constant and appropriate value whatever the environmental conditions. The DltA− mutant displayed the ability to form clumps in standing culture and exhibited an increased susceptibility to the cationic antimicrobial polypeptide colistin.

scholarly journals Biofilm-Related Infections in Gram-Positive Bacteria and the Potential Role of the Long-Acting Agent Dalbavancin

2021 ◽  
Vol 12 ◽  
Author(s):  
Alessandra Oliva ◽  
Stefania Stefani ◽  
Mario Venditti ◽  
Enea Gino Di Domenico
Keyword(s):  
Public Health Problem ◽  
Major Public Health Problem ◽  
Bacterial Cells ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Wide Range ◽  
Long Acting ◽  
Acting Agent ◽  
Biofilm Development

Infections caused by Gram-positive bacteria are a major public health problem due to their increasing resistance to antibiotics. Staphylococcus and Enterococcus species’ resistance and pathogenicity are enhanced by their ability to form biofilm. The biofilm lifestyle represents a significant obstacle to treatment because bacterial cells become highly tolerant to a wide range of antimicrobial compounds normally effective against their planktonic forms. Thus, novel therapeutic strategies targeting biofilms are urgently needed. The lipoglycopeptide dalbavancin is a long-acting agent for treating acute bacterial skin and skin structure infections caused by a broad range of Gram-positive pathogens. Recent studies have shown promising activity of dalbavancin against Gram-positive biofilms, including methicillin-resistant S. aureus (MRSA), methicillin-resistant S. epidermidis (MRSE), and vancomycin-susceptible enterococci. This review outlines the mechanisms regulating biofilm development in Staphylococcus and Enterococcus species and the clinical impact of biofilm-related infections. In addition, it discusses the clinical implications and potential therapeutic perspectives of the long-acting drug dalbavancin against biofilm-forming Gram-positive pathogens.

scholarly journals Pilus hijacking by a bacterial coaggregation factor critical for oral biofilm development

2014 ◽  
Vol 111 (10) ◽  
pp. 3835-3840 ◽  
Author(s):  
Melissa E. Reardon-Robinson ◽  
Chenggang Wu ◽  
Arunima Mishra ◽  
Chungyu Chang ◽  
Naomi Bier ◽  
...  
Keyword(s):  
Surface Proteins ◽  
Phenotypic Characterization ◽  
Oral Biofilm ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Streptococcus Oralis ◽  
Oral Microbes ◽  
Biofilm Development

The formation of dental plaque, a highly complex biofilm that causes gingivitis and periodontitis, requires specific adherence among many oral microbes, including the coaggregation ofActinomyces oriswithStreptococcus oralisthat helps to seed biofilm development. Here, we report the discovery of a key coaggregation factor for this process. This protein, which we named coaggregation factor A (CafA), is one of 14 cell surface proteins with the LPXTG motif predicted inA. orisMG1, whose function was hitherto unknown. By systematic mutagenesis of each of these genes and phenotypic characterization, we found that theActinomyces/Streptococcuscoaggregation is only abolished by deletion ofcafA. Subsequent biochemical and cytological experiments revealed that CafA constitutes the tip of a unique form of the type 2 fimbria long known for its role in coaggregation. The direct and predominant role of CafA in adherence is evident from the fact that CafA or an antibody against CafA inhibits coaggregation, whereas the shaft protein FimA or a polyclonal antibody against FimA has no effect. Remarkably, FimA polymerization was blocked by deletion of genes for both CafA and FimB, the previously described tip protein of the type 2 fimbria. Together, these results indicate that some surface proteins not linked to a pilus gene cluster in Gram-positive bacteria may hijack the pilus. These unique tip proteins displayed on a common pilus shaft may serve distinct physiological functions. Furthermore, the pilus shaft assembly in Gram-positive bacteria may require a tip, as is true for certain Gram-negative bacterial pili.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

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