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Streeter K, Neuman C, Thompson J, Hatje E, Katouli M. The characteristics of genetically related Pseudomonas aeruginosa from diverse sources and their interaction with human cell lines. Can J Microbiol 2016; 62:233-40. [DOI: 10.1139/cjm-2015-0536] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated a collection of Pseudomonas aeruginosa strains from hospitalised patients (n = 20) and various environmental sources (n = 214) for their genetic relatedness; virulence properties; antibiotic resistance; and interaction with intestinal (Caco-2), renal (A-498), and lung (Calu-3) cell lines. Using RAPD–PCR, we found high diversity among the strains irrespective of their sources, with only 6 common (C) types containing strains from both a clinical and environmental source. Environmental strains belonging to these C-types showed greater adhesion to A-498 cells than did clinical strains (17 ± 13 bacteria/cell versus 13 ± 11 bacteria/cell; p < 0.001), whereas clinical strains showed significantly greater adhesion to Calu-3 and Caco-2 cells than did environmental strains (p < 0.001 for both). The virulence genes and antibiotic resistance profiles of the strains were similar; however, the prevalence of environmental strains carrying both exoS and exoU was significantly (p < 0.0368) higher than clinical strains. While all strains were resistant to ticarcillin and ticarcillin–clavulanic acid, resistance against aztreonam, gentamicin, amikacin, piperacillin, and ceftazidime varied among environmental and clinical strains. These results suggest that environmental strains of P. aeruginosa carry virulence properties similar to clinical strains, including adhesion to various human cell lines, with some strains showing a higher adhesion to specific cell lines, indicating they may have a better ability to cause infection in those sites under predisposing conditions of the host.
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Affiliation(s)
- Klrissa Streeter
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
| | - Christina Neuman
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
| | - Jasmin Thompson
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
| | - Eva Hatje
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
| | - Mohammad Katouli
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
- Genecology Research Centre, School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
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Parker D, Ahn D, Cohen T, Prince A. Innate Immune Signaling Activated by MDR Bacteria in the Airway. Physiol Rev 2016; 96:19-53. [PMID: 26582515 DOI: 10.1152/physrev.00009.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Health care-associated bacterial pneumonias due to multiple-drug resistant (MDR) pathogens are an important public health problem and are major causes of morbidity and mortality worldwide. In addition to antimicrobial resistance, these organisms have adapted to the milieu of the human airway and have acquired resistance to the innate immune clearance mechanisms that normally prevent pneumonia. Given the limited efficacy of antibiotics, bacterial clearance from the airway requires an effective immune response. Understanding how specific airway pathogens initiate and regulate innate immune signaling, and whether this response is excessive, leading to host-induced pathology may guide future immunomodulatory therapy. We will focus on three of the most important causes of health care-associated pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, and review the mechanisms through which an inappropriate or damaging innate immune response is stimulated, as well as describe how airway pathogens cause persistent infection by evading immune activation.
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Affiliation(s)
- Dane Parker
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Danielle Ahn
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Taylor Cohen
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Alice Prince
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
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Emami S, Nikokar I, Ghasemi Y, Ebrahimpour M, Sedigh Ebrahim-Saraie H, Araghian A, Faezi S, Farahbakhsh M, Rajabi A. Antibiotic Resistance Pattern and Distribution of pslA Gene Among Biofilm Producing Pseudomonas aeruginosa Isolated From Waste Water of a Burn Center. Jundishapur J Microbiol 2015; 8:e23669. [PMID: 26855739 PMCID: PMC4735833 DOI: 10.5812/jjm.23669] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 01/16/2015] [Accepted: 02/05/2015] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Pseudomonas aeruginosa is considered as a major cause of hospital-acquired infections due to its high antibacterial resistance. Biofilm formation is a well-known pathogenic mechanism in P. aeruginosa infections, since sessile bacteria are protected in an extracellular matrix of exopolysaccharide. The expression of polysaccharide synthesis locus (pslA gene) can be important for biofilm formation by P. aeruginosa. OBJECTIVES The purpose of this research was to evaluate the antibiotic resistance pattern and distribution of the pslA gene among biofilm-producing P. aeruginosa isolates obtained from waste water of Burn Centre in Guilan, Iran. MATERIALS AND METHODS Fifty isolates of P. aeruginosa were obtained from waste water of a burn center. The P. aeruginosa isolates were identified using standard bacteriological procedures. Drug susceptibility test was performed by disk diffusion method for all the isolates against nine antimicrobial agents. Biofilm formation was measured by microtiter plate assay. Polymerase chain reaction (PCR) was used to identify the presence of the pslA gene among the isolates. RESULTS Biofilm formation was observed in 70% of the P. aeruginosa isolates. The potential formation of biofilm was significantly associated with resistance to gentamicin, imipenem, tobramycin and piperacillin. In addition, the pslA gene only existed in biofilm-producing isolates with a frequency of 42.9% (n = 15). CONCLUSIONS The findings of the present study well demonstrated that the P. aeruginosa biofilm-producing isolates were more resistant to the tested antibiotics. Furthermore, because of wide distribution, it seems that the pslA gene is associated with biofilm formation.
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Affiliation(s)
- Shiva Emami
- Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran
| | - Iraj Nikokar
- Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran
- Corresponding author: Iraj Nikokar, Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran. Tel: +98-1425237070, Fax: +98-1425237171, E-mail:
| | - Yusuf Ghasemi
- Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran
| | - Monireh Ebrahimpour
- Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran
| | - Hadi Sedigh Ebrahim-Saraie
- Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran
| | - Afshin Araghian
- Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran
| | - Sobhan Faezi
- Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran
| | - Mojtaba Farahbakhsh
- Department of Biotechnology, Laboratory of Microbiology and Immunology of Infectious Diseases, Para Medicine Faculty, Guilan University of Medical Sciences, Rasht, IR Iran
| | - Abdolhalim Rajabi
- Department of Epidemiology, Faculty of Public Health, Iran University of Medical Sciences, Tehran, IR Iran
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Cheng C, Du L, Yu J, Lu Q, He Y, Ran T. Ciprofloxacin plus erythromycin or ambroxol ameliorates endotracheal tube-associated Pseudomonas aeruginosa biofilms in a rat model. Pathol Res Pract 2015; 211:982-8. [PMID: 26601615 DOI: 10.1016/j.prp.2015.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 09/27/2015] [Accepted: 10/02/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVE Pseudomonas aeruginosa is a multi-drug resistant bacterium, with its biofilm-growing mucoid (alginate-producing) strains being particularly resistant. As atomized drug administration is a common practice in pediatric patients, we compared the effect of inhalational therapy with erythromycin plus ciprofloxacin, with that of ambroxol plus ciprofloxacin, against biofilm producing strains of P. aeruginosa. RESULTS Both combined treatment regimens were associated with a significant reduction in bacterial counts in endotracheal (ET) tubes and lungs, as compared to that observed with ambroxol and erythromycin monotherapies (P<0.05). Ciprofloxacin plus ambroxol appeared to have a higher efficacy than ciprofloxacin plus erythromycin, both in lowering bacterial counts (P<0.05) and in disrupting the structural integrity of biofilm. Histopathological changes in the lungs were milder in the two combined treatment groups, as compared to that in groups treated with single drugs. CONCLUSION Erythromycin or ambroxol in combination with ciprofloxacin could eliminate P. aeruginosa biofilms. When combined with ciprofloxacin, ambroxol outperformed erythromycin in eradicating P. aeruginosa biofilm.
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Affiliation(s)
- Chen Cheng
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Lizhong Du
- The Children's Hospital, Zhejiang University School of Medicine, China
| | - Jialin Yu
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China.
| | - Qi Lu
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Yu He
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Tao Ran
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China
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Genetic Adaptation of Achromobacter sp. during Persistence in the Lungs of Cystic Fibrosis Patients. PLoS One 2015; 10:e0136790. [PMID: 26313451 PMCID: PMC4552427 DOI: 10.1371/journal.pone.0136790] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 08/07/2015] [Indexed: 12/26/2022] Open
Abstract
Achromobacter species are increasingly isolated from the respiratory tract of cystic fibrosis patients and often a chronic infection is established. How Achromobacter sp. adapts to the human host remains uncharacterised. By comparing longitudinally collected isolates of Achromobacter sp. isolated from five CF patients, we have investigated the within-host evolution of clonal lineages. The majority of identified mutations were isolate-specific suggesting co-evolution of several subpopulations from the original infecting isolate. The largest proportion of mutated genes were involved in the general metabolism of the bacterium, but genes involved in virulence and antimicrobial resistance were also affected. A number of virulence genes required for initiation of acute infection were selected against, e.g. genes of the type I and type III secretion systems and genes related to pilus and flagellum formation or function. Six antimicrobial resistance genes or their regulatory genes were mutated, including large deletions affecting the repressor genes of an RND-family efflux pump and a beta-lactamase. Convergent evolution was observed for five genes that were all implicated in bacterial virulence. Characterisation of genes involved in adaptation of Achromobacter to the human host is required for understanding the pathogen-host interaction and facilitate design of future therapeutic interventions.
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106
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Sánchez-Gómez S, Ferrer-Espada R, Stewart PS, Pitts B, Lohner K, Martínez de Tejada G. Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms. BMC Microbiol 2015; 15:137. [PMID: 26149536 PMCID: PMC4491869 DOI: 10.1186/s12866-015-0473-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/26/2015] [Indexed: 12/05/2022] Open
Abstract
Background Infections by Pseudomonas aeruginosa constitute a serious health threat because this pathogen –particularly when it forms biofilms – can acquire resistance to the majority of conventional antibiotics. This study evaluated the antimicrobial activity of synthetic peptides based on LF11, an 11-mer peptide derived from human lactoferricin against P. aeruginosa planktonic and biofilm-forming cells. We included in this analysis selected N-acylated derivatives of the peptides to analyze the effect of acylation in antimicrobial activity. To assess the efficacy of compounds against planktonic bacteria, microdilution assays to determine the minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill studies were conducted. The anti-biofilm activity of the agents was assessed on biofilms grown under static (on microplates) and dynamic (in a CDC-reactor) flow regimes. Results The antimicrobial activity of lipopeptides differed from that of non-acylated peptides in their killing mechanisms on planktonic and biofilm-forming cells. Thus, acylation enhanced the bactericidal activity of the parental peptides and resulted in lipopeptides that were uniformly bactericidal at their MIC. In contrast, acylation of the most potent anti-biofilm peptides resulted in compounds with lower anti-biofilm activity. Both peptides and lipopeptides displayed very rapid killing kinetics and all of them required less than 21 min to reduce 1,000 times the viability of planktonic cells when tested at 2 times their MBC. The peptides, LF11-215 (FWRIRIRR) and LF11-227 (FWRRFWRR), displayed the most potent anti-biofilm activity causing a 10,000 fold reduction in cell viability after 1 h of treatment at 10 times their MIC. At that concentration, these two compounds exhibited low citotoxicity on human cells. In addition to its bactericidal activity, LF11-227 removed more that 50 % of the biofilm mass in independent assays. Peptide LF11-215 and two of the shortest and least hydrophobic lipopeptides, DI-MB-LF11-322 (2,2-dimethylbutanoyl-PFWRIRIRR) and DI-MB-LF11-215, penetrated deep into the biofilm structure and homogenously killed biofilm-forming bacteria. Conclusion We identified peptides derived from human lactoferricin with potent antimicrobial activity against P. aeruginosa growing either in planktonic or in biofilm mode. Although further structure-activity relationship analyses are necessary to optimize the anti-biofilm activity of these compounds, the results indicate that lactoferricin derived peptides are promising anti-biofilm agents.
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Affiliation(s)
- Susana Sánchez-Gómez
- Department of Microbiology, University of Navarra, Irunlarrea 1, E-31008, Pamplona, Spain. .,Present address: Susana Sánchez-Gómez, Bionanoplus, 31110, Noain, Spain.
| | - Raquel Ferrer-Espada
- Department of Microbiology, University of Navarra, Irunlarrea 1, E-31008, Pamplona, Spain.
| | - Philip S Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA.
| | - Betsey Pitts
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA.
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria.
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Sodium houttuyfonate inhibits biofilm formation and alginate biosynthesis-associated gene expression in a clinical strain of Pseudomonas aeruginosa in vitro. Exp Ther Med 2015; 10:753-758. [PMID: 26622388 DOI: 10.3892/etm.2015.2562] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 05/08/2015] [Indexed: 11/05/2022] Open
Abstract
The increasing multidrug resistance of Pseudomonas aeruginosa has become a serious public-health problem. In the present study, the inhibitory activities of sodium houttuyfonate (SH) against biofilm formation and alginate production in a clinical strain of P.aeruginosa (AH16) were investigated in vitro using crystal violet dying and standard curve methods, respectively. The cellular morphology of P. aeruginosa treated with SH was observed using a scanning electron microscope. Furthermore, reverse transcription-quantitative polymerase chain reaction was used to identify differences in the expression levels of genes associated with alginate biosynthesis as a result of the SH treatment. The results indicated that SH significantly inhibited biofilm formation, and decreased the levels of the primary biofilm constituent, alginate, in P. aeruginosa AH16 at various stages of biofilm development. In addition, scanning electron microscopy observations demonstrated that SH markedly altered the cellular morphology and biofilm structure of P. aeruginosa. Furthermore, the results from the reverse transcription-quantitative polymerase chain reaction analysis indicated that SH inhibited biofilm formation by mitigating the expression of the algD and algR genes, which are associated with alginate biosynthesis. Therefore, the present study has provided novel insights into the potent effects and underlying mechanisms of SH-induced inhibition of biofilm formation in a clinical strain of P. aeruginosa.
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108
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Whitfield GB, Marmont LS, Howell PL. Enzymatic modifications of exopolysaccharides enhance bacterial persistence. Front Microbiol 2015; 6:471. [PMID: 26029200 PMCID: PMC4432689 DOI: 10.3389/fmicb.2015.00471] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 04/29/2015] [Indexed: 12/25/2022] Open
Abstract
Biofilms are surface-attached communities of bacterial cells embedded in a self-produced matrix that are found ubiquitously in nature. The biofilm matrix is composed of various extracellular polymeric substances, which confer advantages to the encapsulated bacteria by protecting them from eradication. The matrix composition varies between species and is dependent on the environmental niche that the bacteria inhabit. Exopolysaccharides (EPS) play a variety of important roles in biofilm formation in numerous bacterial species. The ability of bacteria to thrive in a broad range of environmental settings is reflected in part by the structural diversity of the EPS produced both within individual bacterial strains as well as by different species. This variability is achieved through polymerization of distinct sugar moieties into homo- or hetero-polymers, as well as post-polymerization modification of the polysaccharide. Specific enzymes that are unique to the production of each polymer can transfer or remove non-carbohydrate moieties, or in other cases, epimerize the sugar units. These modifications alter the physicochemical properties of the polymer, which in turn can affect bacterial pathogenicity, virulence, and environmental adaptability. Herein, we review the diversity of modifications that the EPS alginate, the Pel polysaccharide, Vibrio polysaccharide, cepacian, glycosaminoglycans, and poly-N-acetyl-glucosamine undergo during biosynthesis. These are EPS produced by human pathogenic bacteria for which studies have begun to unravel the effect modifications have on their physicochemical and biological properties. The biological advantages these polymer modifications confer to the bacteria that produce them will be discussed. The expanding list of identified modifications will allow future efforts to focus on linking these modifications to specific biosynthetic genes and biofilm phenotypes.
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Affiliation(s)
- Gregory B Whitfield
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Lindsey S Marmont
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - P Lynne Howell
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
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Hoefer D, Schnepf JK, Hammer TR, Fischer M, Marquardt C. Biotechnologically produced microbial alginate dressings show enhanced gel forming capacity compared to commercial alginate dressings of marine origin. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:162. [PMID: 25786399 DOI: 10.1007/s10856-015-5492-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/15/2015] [Indexed: 06/04/2023]
Abstract
Marine alginate fibre dressings are well established in wound management. Alginate fibres can absorb plenty of wound exudate due to their gel forming abilities and ion exchange. Alginates from bacteria have never been studied for medical applications so far, although the microbial polymer raises expectations for improved gelling capacity due to its unique O-acetylation. To prove the gelling capacity of bacterial alginate, we extracted the co-polymer from fermentation of the soil bacterium Azotobacter vinelandii ATCC 9046, cultivated on crude glycerol as an alternative carbon source. Bacterial alginate was isolated in high purity and extruded by a wet spinning method. Fibre structure and properties were characterised by infrared spectroscopy, NMR, GPC, scanning electron microscopy and tensile testing. The fibres could be processed into biocompatible needle web dressings, which showed more than twice the gel formation in saline compared to commercial dressings made of marine alginates. Gelled dressings of bacterial alginate formed stable hydrogels of sufficient shape and strength for wound healing applications. This work suggests that the increased gel formation of bacterial alginate from A. vinelandii may be optimal for the preparation of novel wound dressings.
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Affiliation(s)
- Dirk Hoefer
- Department of Hygiene, Environment and Medicine, Hohenstein Institutes, Schlosssteige 1, 74357, Boennigheim, Germany,
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110
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Abstract
Endodontic disease is a biofilm-mediated infection, and primary aim in the management of endodontic disease is the elimination of bacterial biofilm from the root canal system. The most common endodontic infection is caused by the surface-associated growth of microorganisms. It is important to apply the biofilm concept to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is foremost to understand how the biofilm formed by root canal bacteria resists endodontic treatment measures. Bacterial etiology has been confirmed for common oral diseases such as caries and periodontal and endodontic infections. Bacteria causing these diseases are organized in biofilm structures, which are complex microbial communities composed of a great variety of bacteria with different ecological requirements and pathogenic potential. The biofilm community not only gives bacteria effective protection against the host's defense system but also makes them more resistant to a variety of disinfecting agents used as oral hygiene products or in the treatment of infections. Successful treatment of these diseases depends on biofilm removal as well as effective killing of biofilm bacteria. So, the fundamental to maintain oral health and prevent dental caries, gingivitis, and periodontitis is to control the oral biofilms. From these aspects, the formation of biofilms carries particular clinical significance because not only host defense mechanisms but also therapeutic efforts including chemical and mechanical antimicrobial treatment measures have the most difficult task of dealing with organisms that are gathered in a biofilm. The aim of this article was to review the mechanisms of biofilms’ formation, their roles in pulpal and periapical pathosis, the different types of biofilms, the factors influencing biofilm formation, the mechanisms of their antimicrobial resistance, techniques to identify biofilms.
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Affiliation(s)
- Kapil Jhajharia
- Department of Conservative Dentistry and Endodontics, Faculty of Dentistry, Melaka Manipal Medical College, Melaka, Malaysia
| | - Abhishek Parolia
- Department of Restorative Dentistry, Faculty of Dentistry, International Medical University, Kuala Lumpur, Malaysia
| | - K Vikram Shetty
- Department of Conservative Dentistry and Endodontics, Faculty of Dentistry, Melaka Manipal Medical College, Melaka, Malaysia
| | - Lata Kiran Mehta
- Department of Pedodontics and Preventive Dentistry, P. D. M. Dental College and Research Institute, Jhajjar, Haryana, India
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Gowrishankar S, Kamaladevi A, Ayyanar KS, Balamurugan K, Pandian SK. Bacillus amyloliquefaciens-secreted cyclic dipeptide – cyclo(l-leucyl-l-prolyl) inhibits biofilm and virulence production in methicillin-resistant Staphylococcus aureus. RSC Adv 2015. [DOI: 10.1039/c5ra11641d] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The current study explores the inhibitory efficacy of cyclo(l-leucyl-l-prolyl) (CLP), a cyclic dipeptide fromBacillus amyloliquefacienson the biofilm and virulence production of methicillin-resistantStaphylococcus aureus(MRSA).
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Affiliation(s)
| | - Arumugam Kamaladevi
- Department of Biotechnology
- Alagappa University
- Science Campus
- Karaikudi – 630 004
- India
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113
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Wesseling W. Beneficial biofilms in marine aquaculture? Linking points of biofilm formation mechanisms in <em>Pseudomonas aeruginosa</em> and <em>Pseudoalteromonas</em> species. AIMS BIOENGINEERING 2015. [DOI: 10.3934/bioeng.2015.3.104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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114
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Saeb AT, David SK, Al-Brahim H. In silico detection of virulence gene homologues in the human pathogen sphingomonas spp. Evol Bioinform Online 2014; 10:229-38. [PMID: 25574122 PMCID: PMC4266192 DOI: 10.4137/ebo.s20710] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 11/09/2014] [Accepted: 11/11/2014] [Indexed: 11/05/2022] Open
Abstract
There is an ongoing debate about the clinical significance of Sphingomonas paucimobilis as a virulent bacterial pathogen. In the present study, we investigated the presence of different virulence factors and genes in Sphingomonas bacteria. We utilized phylogenetic, comparative genomics and bioinformatics analysis to investigate the potentiality of Sphingomonas bacteria as virulent pathogenic bacteria. The 16S ribosomal RNA gene (16S rDNA) phylogenetic tree showed that the closest bacterial taxon to Sphingomonas is Brucella with a bootstrap value of 87 followed by Helicobacter, Campylobacter, Pseudomonas, and then Legionella. Sphingomonas shared no virulence factors with Helicobacter or Campylobacter, despite their close phylogenic relationship. In spite of the phylogenetic divergence between Sphingomonas and Pseudomonas, they shared many major virulence factors, such as adherence, antiphagocytosis, iron uptake, proteases, and quorum sensing. In conclusion, Sphingomonas spp. contains several major virulence factors resembling Pseudomonas sp., Legionella sp., Brucella sp., and Bordetella sp. virulence factors. Similarity of virulence factors did not match phylogenetic relationships. These findings suggest horizontal gene transfer of virulence factors rather than sharing a common pathogenic ancestor. Sphingomonas spp. is potential virulent bacterial pathogen.
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Affiliation(s)
- Amr Tm Saeb
- Biotechnology Department, Strategic Center for Diabetes Research, King Saud University, Riyadh, Saudi Arabia
| | - Satish Kumar David
- Information Technology Department, Strategic Center for Diabetes Research, King Saud University, Riyadh, Saudi Arabia
| | - Hissa Al-Brahim
- Biotechnology Department, Strategic Center for Diabetes Research, King Saud University, Riyadh, Saudi Arabia
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Characterization of the algC gene expression pattern in the multidrug resistant Acinetobacter baumannii AIIMS 7 and correlation with biofilm development on abiotic surface. ScientificWorldJournal 2014; 2014:593546. [PMID: 25544957 PMCID: PMC4269089 DOI: 10.1155/2014/593546] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/10/2014] [Accepted: 11/10/2014] [Indexed: 01/06/2023] Open
Abstract
Relative quantification of algC gene expression was evaluated in the multidrug resistant strain Acinetobacter baumannii AIIMS 7 biofilm (3 to 96 h, on polystyrene surface) compared to the planktonic counterparts. Comparison revealed differential algC expression pattern with maximum 81.59-fold increase in biofilm cells versus 3.24-fold in planktonic cells (P < 0.05). Expression levels strongly correlated with specific biofilm stages (scale of 3 to 96 h), coinciding maximum at initial surface attachment stage (9 h) and biofilm maturation stage (48 h). Cloning, heterologous expression, and bioinformatics analyses indicated algC gene product as the bifunctional enzyme phosphomannomutase/phosphoglucomutase (PMM/PGM) of ∼ 53 kDa size, which augmented biofilms significantly in algC clones compared to controls (lacking algC gene), further localized by scanning electron microscopy. Moreover, molecular dynamics analysis on the three-dimensional structure of PMM/PGM (simulated up to 10 ns) revealed enzyme structure as stable and similar to that in P. aeruginosa (synthesis of alginate and lipopolysaccharide core) and involved in constitution of biofilm EPS (extracellular polymeric substances). Our observation on differential expression pattern of algC having strong correlation with important biofilm stages, scanning electron-microscopic evidence of biofilm augmentation taken together with predictive enzyme functions via molecular dynamic (MD) simulation, proposes a new basis of A. baumannii AIIMS 7 biofilm development on inanimate surfaces.
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116
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Gutman J, Herzberg M, Walker SL. Biofouling of reverse osmosis membranes: positively contributing factors of Sphingomonas. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:13941-13950. [PMID: 25354089 DOI: 10.1021/es503680s] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the present study, we investigate the possible contribution of Sphingomonas spp. glycosphingolipids (GSL) and its extracellular polymeric substances (EPS) to the initial colonization and development of biofilm bodies on reverse osmosis (RO) membranes. A combination of an RO cross-flow membrane lab unit, a quartz crystal microbalance with dissipation (QCM-D), and a rear stagnation point flow (RSPF) system with either model bacteria (Sphingomonas wittichii, Escherichia coli, and Pseudomonas aeruginosa) or vesicles made of the bacterial GSL or LPS was used. Results showed noticeable differences in the adhesion LPS versus GSL vesicles in the QCM-D, with the latter exhibiting 50% higher adhesion to polyamide coated crystals (mimicking an RO membrane surface). A similar trend was observed for EPS extracted from S. wittichii, when compared to the adhesion tendency of EPS extracted from P. aeruginosa. By applying the whole-cell approach in the RO lab unit, the cumulative impact of S. wittichii cells composing GSL and probably their EPS reduced the permeate flux during bacterial accumulation on the membrane surface. Experiments were conducted with the same amount of Sphingomonas spp. or Escherichia coli cells resulting in a two times greater flux decline in the presence of S. wittichii. The distinct effects of Sphingomonas spp. on RO membrane biofouling are likely a combination of GSL presence (known for enhancing adhesion when compared to non-GSL containing bacteria) and the EPS contributing to the overall strength of the biofilm matrix.
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Affiliation(s)
- Jenia Gutman
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Albert Katz International School for Desert Studies, Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev , Sede Boqer Campus 84990, Israel
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Barnes RJ, Bandi RR, Chua F, Low JH, Aung T, Barraud N, Fane AG, Kjelleberg S, Rice SA. The roles of Pseudomonas aeruginosa extracellular polysaccharides in biofouling of reverse osmosis membranes and nitric oxide induced dispersal. J Memb Sci 2014. [DOI: 10.1016/j.memsci.2014.04.046] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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118
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Baker P, Ricer T, Moynihan PJ, Kitova EN, Walvoort MTC, Little DJ, Whitney JC, Dawson K, Weadge JT, Robinson H, Ohman DE, Codée JDC, Klassen JS, Clarke AJ, Howell PL. P. aeruginosa SGNH hydrolase-like proteins AlgJ and AlgX have similar topology but separate and distinct roles in alginate acetylation. PLoS Pathog 2014; 10:e1004334. [PMID: 25165982 PMCID: PMC4148444 DOI: 10.1371/journal.ppat.1004334] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Accepted: 07/08/2014] [Indexed: 02/05/2023] Open
Abstract
The O-acetylation of polysaccharides is a common modification used by pathogenic organisms to protect against external forces. Pseudomonas aeruginosa secretes the anionic, O-acetylated exopolysaccharide alginate during chronic infection in the lungs of cystic fibrosis patients to form the major constituent of a protective biofilm matrix. Four proteins have been implicated in the O-acetylation of alginate, AlgIJF and AlgX. To probe the biological function of AlgJ, we determined its structure to 1.83 Å resolution. AlgJ is a SGNH hydrolase-like protein, which while structurally similar to the N-terminal domain of AlgX exhibits a distinctly different electrostatic surface potential. Consistent with other SGNH hydrolases, we identified a conserved catalytic triad composed of D190, H192 and S288 and demonstrated that AlgJ exhibits acetylesterase activity in vitro. Residues in the AlgJ signature motifs were found to form an extensive network of interactions that are critical for O-acetylation of alginate in vivo. Using two different electrospray ionization mass spectrometry (ESI-MS) assays we compared the abilities of AlgJ and AlgX to bind and acetylate alginate. Binding studies using defined length polymannuronic acid revealed that AlgJ exhibits either weak or no detectable polymer binding while AlgX binds polymannuronic acid specifically in a length-dependent manner. Additionally, AlgX was capable of utilizing the surrogate acetyl-donor 4-nitrophenyl acetate to catalyze the O-acetylation of polymannuronic acid. Our results, combined with previously published in vivo data, suggest that the annotated O-acetyltransferases AlgJ and AlgX have separate and distinct roles in O-acetylation. Our refined model for alginate acetylation places AlgX as the terminal acetlytransferase and provides a rationale for the variability in the number of proteins required for polysaccharide O-acetylation. Bacteria utilize many defense strategies to protect themselves against external forces. One mechanism used by the bacterium Pseudomonas aeruginosa is the production of the long sugar polymer alginate. The bacteria use this polymer to form a biofilm – a barrier to protect against antibiotics and the host immune response. During its biosynthesis alginate undergoes a chemical modification whereby acetate is added to the polymer. Acetylation of alginate is important as this modification makes the bacterial biofilm less susceptible to recognition and clearance by the host immune system. In this paper we present the atomic structure of AlgJ; one of four proteins required for O-acetylation of the polymer. AlgJ is structurally similar to AlgX, which we have shown previously is also required for alginate acetylation. To understand why both enzymes are required for O-acetylation we functionally characterized the proteins and found that although AlgJ exhibits acetylesterase activity – catalyzing the removal of acetyl groups from a surrogate substrate – it does not bind to short mannuornic acid polymers. In contrast, AlgX bound alginate in a length-dependent manner and was capable of transfering acetate from a surrogate substrate onto alginate. This has allowed us to not only understand how acetate is added to alginate, but increases our understanding of how acetate is added to other bacterial sugar polymers.
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Affiliation(s)
- Perrin Baker
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Tyler Ricer
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Patrick J. Moynihan
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Elena N. Kitova
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | | | - Dustin J. Little
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - John C. Whitney
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karen Dawson
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Joel T. Weadge
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Howard Robinson
- Photon Sciences Division, Brookhaven National Laboratory, Upton, New York, United States of America
| | - Dennis E. Ohman
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center and McGuire Veterans Affairs Medical Center, Richmond, Virginia, United States of America
| | - Jeroen D. C. Codée
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - John S. Klassen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Anthony J. Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - P. Lynne Howell
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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119
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Lim MH, Wu J, Yao J, Gallardo IF, Dugger JW, Webb LJ, Huang J, Salmi ML, Song J, Clark G, Roux SJ. Apyrase suppression raises extracellular ATP levels and induces gene expression and cell wall changes characteristic of stress responses. PLANT PHYSIOLOGY 2014; 164:2054-67. [PMID: 24550243 PMCID: PMC3982762 DOI: 10.1104/pp.113.233429] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/13/2014] [Indexed: 05/20/2023]
Abstract
Plant cells release ATP into their extracellular matrix as they grow, and extracellular ATP (eATP) can modulate the rate of cell growth in diverse tissues. Two closely related apyrases (APYs) in Arabidopsis (Arabidopsis thaliana), APY1 and APY2, function, in part, to control the concentration of eATP. The expression of APY1/APY2 can be inhibited by RNA interference, and this suppression leads to an increase in the concentration of eATP in the extracellular medium and severely reduces growth. To clarify how the suppression of APY1 and APY2 is linked to growth inhibition, the gene expression changes that occur in seedlings when apyrase expression is suppressed were assayed by microarray and quantitative real-time-PCR analyses. The most significant gene expression changes induced by APY suppression were in genes involved in biotic stress responses, which include those genes regulating wall composition and extensibility. These expression changes predicted specific chemical changes in the walls of mutant seedlings, and two of these changes, wall lignification and decreased methyl ester bonds, were verified by direct analyses. Taken together, the results are consistent with the hypothesis that APY1, APY2, and eATP play important roles in the signaling steps that link biotic stresses to plant defense responses and growth changes.
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120
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Halebeedu PP, Kumar GSV, Gopal S. Revamping the role of biofilm regulating operons in device-associated Staphylococci and Pseudomonas aeruginosa. Indian J Med Microbiol 2014; 32:112-23. [DOI: 10.4103/0255-0857.129766] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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121
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Yahya M, Ibrahim M, Zawawi W, Hamid U. Biofilm Killing Effects of Chromolaena odorata Extracts against Pseudomonas aeruginosa. ACTA ACUST UNITED AC 2014. [DOI: 10.3923/rjphyto.2014.64.73] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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122
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Hay ID, Wang Y, Moradali MF, Rehman ZU, Rehm BHA. Genetics and regulation of bacterial alginate production. Environ Microbiol 2014; 16:2997-3011. [DOI: 10.1111/1462-2920.12389] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 12/18/2013] [Accepted: 12/22/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Iain D. Hay
- Institute of Fundamental Sciences; Massey University; Palmerston North 4442 New Zealand
| | - Yajie Wang
- Institute of Fundamental Sciences; Massey University; Palmerston North 4442 New Zealand
| | - Mohammed F. Moradali
- Institute of Fundamental Sciences; Massey University; Palmerston North 4442 New Zealand
| | - Zahid U. Rehman
- Institute of Fundamental Sciences; Massey University; Palmerston North 4442 New Zealand
| | - Bernd H. A. Rehm
- Institute of Fundamental Sciences; Massey University; Palmerston North 4442 New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology; Massey University; Palmerston North 4442 New Zealand
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123
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Tian L, Xu S, Hutchins WC, Yang CH, Li J. Impact of the exopolysaccharides Pel and Psl on the initial adhesion of Pseudomonas aeruginosa to sand. BIOFOULING 2014; 30:213-222. [PMID: 24404893 DOI: 10.1080/08927014.2013.857405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this study, the impact of the exopolysaccharides Pel and Psl on the cell surface electron donor-electron acceptor (acid-base) properties and adhesion to quartz sand was investigated by using Pseudomonas aeruginosa PAO1 and its isogenic EPS-mutant strains Δpel, Δpsl and Δpel/Δpsl. The microbial adhesion to hydrocarbon (MATH) test and titration results showed that both Pel and Psl contribute to the surface hydrophobicity of the cell. The results of contact angle measurement, however, showed no correlation with the cell surface hydrophobicity measured by the MATH test and the titration method. Packed-bed column experiments indicated that the exopolysaccharides Pel and Psl are involved in the initial cell attachment to the sand surface and the extent of their impact is dependent on the ionic strength (IS) of the solution. Overall, the Δpel/Δpsl double mutant had the lowest adhesion coefficient to sand compared with the wild-type PAO1, the Δpel mutant and the Δpsl mutant. It is hypothesized that in addition to bacterial surface hydrophobicity and DLVO forces, other factors, eg steric repulsion caused by extracellular macromolecules, and cell surface appendages (flagella and pili) also contribute significantly to the interaction between the cell surface and a sand grain.
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Affiliation(s)
- Lulu Tian
- a Department of Civil Engineering and Mechanics , University of Wisconsin-Milwaukee , Milwaukee , WI , USA
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124
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Mi L, Jiang S. Integrated antimicrobial and nonfouling zwitterionic polymers. Angew Chem Int Ed Engl 2014; 53:1746-54. [PMID: 24446141 DOI: 10.1002/anie.201304060] [Citation(s) in RCA: 405] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 07/18/2013] [Indexed: 12/27/2022]
Abstract
Zwitterionic polymers are generally viewed as a new class of nonfouling materials. Unlike their poly(ethylene glycol) (PEG) counterparts, zwitterionic polymers have a broader chemical diversity and greater freedom for molecular design. In this Minireview, we highlight recent microbiological applications of zwitterionic polymers and their derivatives, with an emphasis on several unique molecular strategies to integrate antimicrobial and nonfouling properties. We will also discuss our insights into the bacterial nonfouling performance of zwitterionic polymers and one example of engineering zwitterionic polymer derivatives for antimicrobial wound-dressing applications.
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Affiliation(s)
- Luo Mi
- Department of Chemical Engineering, University of Washington, Seattle, WA 98195 (USA)
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125
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Mi L, Jiang S. Zwitterionische Polymere mit antimikrobiellen und Nonfouling-Eigenschaften. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201304060] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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126
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Fux CA, Stoodley P, Hall-Stoodley L, Costerton JW. Bacterial biofilms: a diagnostic and therapeutic challenge. Expert Rev Anti Infect Ther 2014; 1:667-83. [PMID: 15482163 DOI: 10.1586/14787210.1.4.667] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bacteria have traditionally been regarded as individual organisms growing in homogeneous planktonic populations. However, bacteria in natural environments usually form communities of surface-adherent organisms embedded in an extracellular matrix, called biofilms. Current antimicrobial strategies often fail to control bacteria in the biofilm mode of growth. Treatment failure is particularly frequent in association with intracorporeal or transcutaneous medical devices and compromised host immunity. The rising prevalence of these risk factors over the last decades has paralleled the increase in biofilm infections. This review discusses the shortcomings of current therapies against biofilms both in theory and with clinical examples. Biofilm characteristics are described with a focus on new diagnostic and therapeutic targets.
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Affiliation(s)
- Christoph A Fux
- Center for Biofilm Engineering, Montana State University, USA.
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127
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Metabolite transfer with the fermentation product 2,3-butanediol enhances virulence by Pseudomonas aeruginosa. ISME JOURNAL 2014; 8:1210-20. [PMID: 24401856 DOI: 10.1038/ismej.2013.232] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 11/12/2013] [Accepted: 11/25/2013] [Indexed: 12/25/2022]
Abstract
The respiratory tract of cystic fibrosis (CF) patients harbor persistent microbial communities (CF airway microbiome) with Pseudomonas aeruginosa emerging as a dominant pathogen. Within a polymicrobial infection, interactions between co-habitant microbes can be important for pathogenesis, but even when considered, these interactions are not well understood. Here, we show with in vitro experiments that, compared with glucose, common fermentation products from co-habitant bacteria significantly increase virulence factor production, antimicrobial activity and biofilm formation of P. aeruginosa. The maximum stimulating effect was produced with the fermentation product 2,3-butanediol, which is a substrate for P. aeruginosa, resulting in a metabolic relationship between fermenters and this pathogen. The global transcription regulator LasI LasR, which controls quorum sensing, was upregulated threefold with 2,3-butanediol, resulting in higher phenazine and exotoxin concentrations and improved biofilm formation. This indicates that the success of P. aeruginosa in CF airway microbiomes could be governed by the location within the food web with fermenting bacteria. Our findings suggest that interbacterial metabolite transfer in polymicrobial infections stimulates virulence of P. aeruginosa and could have a considerable impact on disease progression.
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128
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Neu TR, Lawrence JR. Investigation of microbial biofilm structure by laser scanning microscopy. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 146:1-51. [PMID: 24840778 DOI: 10.1007/10_2014_272] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microbial bioaggregates and biofilms are hydrated three-dimensional structures of cells and extracellular polymeric substances (EPS). Microbial communities associated with interfaces and the samples thereof may come from natural, technical, and medical habitats. For imaging such complex microbial communities confocal laser scanning microscopy (CLSM) is the method of choice. CLSM allows flexible mounting and noninvasive three-dimensional sectioning of hydrated, living, as well as fixed samples. For this purpose a broad range of objective lenses is available having different working distance and resolution. By means of CLSM the signals detected may originate from reflection, autofluorescence, reporter genes/fluorescence proteins, fluorochromes binding to specific targets, or other probes conjugated with fluorochromes. Recorded datasets can be used not only for visualization but also for semiquantitative analysis. As a result CLSM represents a very useful tool for imaging of microbiological samples in combination with other analytical techniques.
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Affiliation(s)
- Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research-UFZ, Brueckstrasse 3a, 39114, Magdeburg, Germany,
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129
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Nguyen MTHD, Liu M, Thomas T. Ankyrin-repeat proteins from sponge symbionts modulate amoebal phagocytosis. Mol Ecol 2013; 23:1635-1645. [PMID: 23980812 DOI: 10.1111/mec.12384] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 11/27/2022]
Abstract
Bacteria-eukaryote symbiosis occurs in all stages of evolution, from simple amoebae to mammals, and from facultative to obligate associations. Sponges are ancient metazoans that form intimate symbiotic interactions with complex communities of bacteria. The basic nutritional requirements of the sponge are in part satisfied by the phagocytosis of bacterial food particles from the surrounding water. How bacterial symbionts, which are permanently associated with the sponge, survive in the presence of phagocytic cells is largely unknown. Here, we present the discovery of a genomic fragment from an uncultured gamma-proteobacterial sponge symbiont that encodes for four proteins, whose closest known relatives are found in a sponge genome. Through recombinant approaches, we show that these four eukaryotic-like, ankyrin-repeat proteins (ARP) when expressed in Eschericha coli can modulate phagocytosis of amoebal cells and lead to accumulation of bacteria in the phagosome. Mechanistically, two ARPs appear to interfere with phagosome development in a similar way to reduced vacuole acidification, by blocking the fusion of the early phagosome with the lysosome and its digestive enzymes. Our results show that ARP from sponge symbionts can function to interfere with phagocytosis, and we postulate that this might be one mechanism by which symbionts can escape digestion in a sponge host.
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Affiliation(s)
- Mary T H D Nguyen
- School of Biotechnology and Biomolecular Sciences and Centre for Marine Bio-Innovation, University of New South Wales, Sydney, NSW 2052, Australia
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130
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Hay ID, Ur Rehman Z, Moradali MF, Wang Y, Rehm BHA. Microbial alginate production, modification and its applications. Microb Biotechnol 2013; 6:637-50. [PMID: 24034361 PMCID: PMC3815931 DOI: 10.1111/1751-7915.12076] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/25/2013] [Accepted: 07/06/2013] [Indexed: 11/29/2022] Open
Abstract
Alginate is an important polysaccharide used widely in the food, textile, printing and pharmaceutical industries for its viscosifying, and gelling properties. All commercially produced alginates are isolated from farmed brown seaweeds. These algal alginates suffer from heterogeneity in composition and material properties. Here, we will discuss alginates produced by bacteria; the molecular mechanisms involved in their biosynthesis; and the potential to utilize these bacterially produced or modified alginates for high-value applications where defined material properties are required.
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Affiliation(s)
- Iain D Hay
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
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131
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Castillo T, Heinzle E, Peifer S, Schneider K, Peña M CF. Oxygen supply strongly influences metabolic fluxes, the production of poly(3-hydroxybutyrate) and alginate, and the degree of acetylation of alginate in Azotobacter vinelandii. Process Biochem 2013. [DOI: 10.1016/j.procbio.2013.04.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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132
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Riley LM, Weadge JT, Baker P, Robinson H, Codée JDC, Tipton PA, Ohman DE, Howell PL. Structural and functional characterization of Pseudomonas aeruginosa AlgX: role of AlgX in alginate acetylation. J Biol Chem 2013; 288:22299-314. [PMID: 23779107 DOI: 10.1074/jbc.m113.484931] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The exopolysaccharide alginate, produced by mucoid Pseudomonas aeruginosa in the lungs of cystic fibrosis patients, undergoes two different chemical modifications as it is synthesized that alter the properties of the polymer and hence the biofilm. One modification, acetylation, causes the cells in the biofilm to adhere better to lung epithelium, form microcolonies, and resist the effects of the host immune system and/or antibiotics. Alginate biosynthesis requires 12 proteins encoded by the algD operon, including AlgX, and although this protein is essential for polymer production, its exact role is unknown. In this study, we present the X-ray crystal structure of AlgX at 2.15 Å resolution. The structure reveals that AlgX is a two-domain protein, with an N-terminal domain with structural homology to members of the SGNH hydrolase superfamily and a C-terminal carbohydrate-binding module. A number of residues in the carbohydrate-binding module form a substrate recognition "pinch point" that we propose aids in alginate binding and orientation. Although the topology of the N-terminal domain deviates from canonical SGNH hydrolases, the residues that constitute the Ser-His-Asp catalytic triad characteristic of this family are structurally conserved. In vivo studies reveal that site-specific mutation of these residues results in non-acetylated alginate. This catalytic triad is also required for acetylesterase activity in vitro. Our data suggest that not only does AlgX protect the polymer as it passages through the periplasm but that it also plays a role in alginate acetylation. Our results provide the first structural insight for a wide group of closely related bacterial polysaccharide acetyltransferases.
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Affiliation(s)
- Laura M Riley
- Program in Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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133
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Pradhan AK, Pradhan N, Sukla LB, Panda PK, Mishra BK. Inhibition of pathogenic bacterial biofilm by biosurfactant produced by Lysinibacillus fusiformis S9. Bioprocess Biosyst Eng 2013; 37:139-49. [PMID: 23719930 DOI: 10.1007/s00449-013-0976-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 05/15/2013] [Indexed: 11/29/2022]
Abstract
A biosurfactant producing microbe isolated from a river bank was identified as Lysinibacillus fusiformis S9. It was identified with help of biochemical tests and 16S rRNA gene phylogenetic analysis. The biosurfactant S9BS produced was purified and characterized as glycolipid. The biosurfactant showed remarkable inhibition of biofilm formation by pathogenic bacteria like Escherichia coli and Streptococcus mutans. It was interesting to note that at concentration of 40 μg ml(-1) the biosurfactant did not show any bactericidal activity but restricted the biofilm formation completely. L. fusiformis is reported for the first time to produce a glycolipid type of biosurfactant capable of inhibiting biofilm formation by pathogenic bacteria. The biosurfactant inhibited bacterial attachment and biofilm formation equally well on hydrophilic as well as hydrophobic surfaces like glass and catheter tubing. This property is significant in many biomedical applications where the molecule should help in preventing biofouling of surfaces without being toxic to biotic system.
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Affiliation(s)
- Arun Kumar Pradhan
- Bioresources Engineering Department, CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, 751013, India
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134
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The acetylation degree of alginates in Azotobacter vinelandii ATCC9046 is determined by dissolved oxygen and specific growth rate: studies in glucose-limited chemostat cultivations. J Ind Microbiol Biotechnol 2013; 40:715-23. [PMID: 23640429 DOI: 10.1007/s10295-013-1274-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 04/12/2013] [Indexed: 10/26/2022]
Abstract
Alginates are polysaccharides that may be used as viscosifiers and gel or film-forming agents with a great diversity of applications. The alginates produced by bacteria such as Azotobacter vinelandii are acetylated. The presence of acetyl groups in this type of alginate increases its solubility, viscosity, and swelling capability. The aim of this study was to evaluate, in glucose-limited chemostat cultivations of A. vinelandii ATCC9046, the influence of dissolved oxygen tension (DO) and specific growth rate (μ) on the degree of acetylation of alginates produced by this bacterium. In glucose-limited chemostat cultivations, the degree of alginate acetylation was evaluated under two conditions of DO (1 and 9 %) and for a range of specific growth rates (0.02-0.15 h⁻¹). In addition, the alginate yields and PHB production were evaluated. High DO in the culture resulted in a high degree of alginate acetylation, reaching a maximum acetylation degree of 6.88 % at 9 % DO. In contrast, the increment of μ had a negative effect on the production and acetylation of the polymer. It was found that at high DO (9 %) and low μ, there was a reduction of the respiration rate, and the PHB accumulation was negligible, suggesting that the flux of acetyl-CoA (the acetyl donor) was diverted to alginate acetylation.
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136
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PelA deacetylase activity is required for Pel polysaccharide synthesis in Pseudomonas aeruginosa. J Bacteriol 2013; 195:2329-39. [PMID: 23504011 DOI: 10.1128/jb.02150-12] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Pel polysaccharide serves as an intercellular adhesin for the formation and maintenance of biofilms in the opportunistic pathogen Pseudomonas aeruginosa. Pel biosynthesis requires the products of a seven-gene operon, pelA-pelG, all of which are necessary for Pel-dependent biofilm formation and Pel-related phenotypes. One of the genes, pelA, encodes a protein with a predicted polysaccharide deacetylase domain. In this work, the role of the putative deacetylase domain in Pel production was examined. We first established that purified recombinant PelA hydrolyzed the pseudosubstrate p-nitrophenyl acetate in vitro, and site-specific mutations of predicted deacetylase active-site residues reduced activity greater than 10-fold. Additionally, these mutants were deficient in Pel-dependent biofilm formation and wrinkly colony morphology in vivo. Subcellular fractionation experiments demonstrate that PelA localizes to both the membrane and periplasmic fractions. Finally, antiserum against the Pel polysaccharide was generated, and PelA deacetylase mutants do not produce Pel-reactive material. Taken together, these results suggest that the deacetylase activity of PelA is important for the production of the Pel polysaccharide.
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137
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Nagant C, Pitts B, Stewart PS, Feng Y, Savage PB, Dehaye JP. Study of the effect of antimicrobial peptide mimic, CSA-13, on an established biofilm formed by Pseudomonas aeruginosa. Microbiologyopen 2013; 2:318-25. [PMID: 23436807 PMCID: PMC3633355 DOI: 10.1002/mbo3.77] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 01/24/2013] [Accepted: 01/29/2013] [Indexed: 12/11/2022] Open
Abstract
The formation of a Pseudomonas aeruginosa biofilm, a complex structure enclosing bacterial cells in an extracellular polymeric matrix, is responsible for persistent infections in cystic fibrosis patients leading to a high rate of morbidity and mortality. The protective environment created by the tridimensional structure reduces the susceptibility of the bacteria to conventional antibiotherapy. Cationic steroid antibiotics (CSA)-13, a nonpeptide mimic of antimicrobial peptides with antibacterial activity on planktonic cultures, was evaluated for its ability to interact with sessile cells. Using confocal laser scanning microscopy, we demonstrated that the drug damaged bacteria within an established biofilm showing that penetration did not limit the activity of this antimicrobial agent against a biofilm. When biofilms were grown during exposure to shear forces and to a continuous medium flow allowing the development of robust structures with a complex architecture, CSA-13 reached the bacteria entrapped in the biofilm within 30 min. The permeabilizing effect of CSA-13 could be associated with the death of the bacteria. In static conditions, the compound did not perturb the architecture of the biofilm. This study confirms the potential of CSA-13 as a new strategy to combat persistent infections involving biofilms formed by P. aeruginosa.
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Affiliation(s)
- Carole Nagant
- Laboratoire de Chimie biologique et Médicale et de Microbiologie Pharmaceutique, Faculté de Pharmacie, Université libre de Bruxelles, Brussels, Belgium
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Sanderlin AB, Vogt SJ, Grunewald E, Bergin BA, Codd SL. Biofilm detection in natural unconsolidated porous media using a low-field magnetic resonance system. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:987-992. [PMID: 23256613 DOI: 10.1021/es3040686] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The extent to which T(2) relaxation measurements can be used to determine biofouling in several natural geological sand media using a low-field (275 kHz, 6.5 mT) NMR system has been demonstrated. It has been previously shown that, at high laboratory strength fields (300 MHz, 7 T), T(2) techniques can be used as a bioassay to confirm the growth of biofilm inside opaque porous media with low magnetic susceptibilities such as borosilicate or soda lime glass beads. Additionally decreases in T(2) can be associated with intact biofilm as opposed to degraded biofilm material. However, in natural geological media, the strong susceptibility gradients generated at high fields dominated the T(2) relaxation time distributions and biofilm growth could not be reliably detected. Samples studied included Bacillus mojavensis biofilm in several sand types, as well as alginate solution and alginate gel in several sand types. One of the sand types was highly magnetic. Data was collected with a low-field (275 kHz, 6.5 mT) benchtop NMR system using a CPMG sequence with an echo time of 1.25 ms providing the ability to detect signals with T(2) greater than 1 ms. Data presented here clearly demonstrate that biofilm can be reliably detected and monitored in highly magnetically susceptible geological samples using a low-field NMR spectrometer indicating that low-field NMR could be viable as a biofilm sensor at bioremedation sites.
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Affiliation(s)
- Alexis B Sanderlin
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, USA
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139
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Whitney JC, Howell PL. Synthase-dependent exopolysaccharide secretion in Gram-negative bacteria. Trends Microbiol 2012; 21:63-72. [PMID: 23117123 DOI: 10.1016/j.tim.2012.10.001] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/28/2012] [Accepted: 10/03/2012] [Indexed: 01/26/2023]
Abstract
The biosynthesis and export of bacterial cell-surface polysaccharides is known to occur through several distinct mechanisms. Recent advances in the biochemistry and structural biology of several proteins in synthase-dependent polysaccharide secretion systems have identified key conserved components of this pathway in Gram-negative bacteria. These components include an inner-membrane-embedded polysaccharide synthase, a periplasmic tetratricopeptide repeat (TPR)-containing scaffold protein, and an outer-membrane β-barrel porin. There is also increasing evidence that many synthase-dependent systems are post-translationally regulated by the bacterial second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). Here, we compare these core proteins in the context of the alginate, cellulose, and poly-β-D-N-acetylglucosamine (PNAG) secretion systems.
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Affiliation(s)
- J C Whitney
- Program in Molecular Structure and Function, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
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Abstract
Bacterial biofilms are defined as a surface attached community of bacteria embedded in a matrix of extracellular polymeric substances that they have produced. When in the biofilm state, bacteria are more resistant to antibiotics and the host immune response than are their planktonic counterparts. Biofilms are increasingly recognized as being significant in human disease, accounting for 80% of bacterial infections in the body and diseases associated with bacterial biofilms include: lung infections of cystic fibrosis patients, colitis, urethritis, conjunctivitis, otitis, endocarditis and periodontitis. Additionally, biofilm infections of indwelling medical devices are of particular concern, as once the device is colonized infection is virtually impossible to eradicate. Given the prominence of biofilms in infectious diseases, there has been an increased effort toward the development of small molecules that will modulate bacterial biofilm development and maintenance. In this review, we highlight the development of small molecules that inhibit and/or disperse bacterial biofilms through non-microbicidal mechanisms. The review discuses the numerous approaches that have been applied to the discovery of lead small molecules that mediate biofilm development. These approaches are grouped into: (1) the identification and development of small molecules that target one of the bacterial signaling pathways involved in biofilm regulation, (2) chemical library screening for compounds with anti-biofilm activity, and (3) the identification of natural products that possess anti-biofilm activity, and the chemical manipulation of these natural products to obtain analogues with increased activity.
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Díaz-Visurraga J, Daza C, Pozo C, Becerra A, von Plessing C, García A. Study on antibacterial alginate-stabilized copper nanoparticles by FT-IR and 2D-IR correlation spectroscopy. Int J Nanomedicine 2012; 7:3597-612. [PMID: 22848180 PMCID: PMC3405878 DOI: 10.2147/ijn.s32648] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The objective of this study was to clarify the intermolecular interaction between antibacterial copper nanoparticles (Cu NPs) and sodium alginate (NaAlg) by Fourier transform infrared spectroscopy (FT-IR) and to process the spectra applying two-dimensional infrared (2D-IR) correlation analysis. To our knowledge, the addition of NaAlg as a stabilizer of copper nanoparticles has not been previously reported. It is expected that the obtained results will provide valuable additional information on: (1) the influence of reducing agent ratio on the formation of copper nanoparticles in order to design functional nanomaterials with increased antibacterial activity, and (2) structural changes related to the incorporation of Cu NPs into the polymer matrix. METHODS Cu NPs were prepared by microwave heating using ascorbic acid as reducing agent and NaAlg as stabilizing agent. The characterization of synthesized Cu NPs by ultraviolet visible spectroscopy, transmission electron microscopy (TEM), electron diffraction analysis, X-ray diffraction (XRD), and semiquantitative analysis of the weight percentage composition indicated that the average particle sizes of Cu NPs are about 3-10 nm, they are spherical in shape, and consist of zerovalent Cu and Cu₂O. Also, crystallite size and relative particle size of stabilized Cu NPs were calculated by XRD using Scherrer's formula and FT from the X-ray diffraction data. Thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry (DSC), FT-IR, second-derivative spectra, and 2D-IR correlation analysis were applied to studying the stabilization mechanism of Cu NPs by NaAlg molecules. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of stabilized Cu NPs against five bacterial strains (Staphylococccus aureus ATCC 6538P, Escherichia coli ATCC 25922 and O157: H7, and Salmonella enterica serovar Typhimurium ATCC 13311 and 14028) were evaluated with macrodilution, agar dilution plate count, and well-diffusion methods. RESULTS On the basis of the semiquantitative analysis, there was a direct correlation between the reducing agent ratio and the percentage of zerovalent Cu. This was confirmed with the statistical analysis of population of Cu NPs from TEM micrographs. At lower reducing agent ratios, two phases coexist (Cu₂O and zerovalent Cu) due to incomplete reduction of copper ions by the reducing agent; however, at higher reducing agent ratios, the Cu NPs consist mainly of zerovalent Cu. Crystallite size and relative particle size of stabilized Cu NPs showed considerable differences in results and tendencies in respect to TEM analysis. However, the relative particle size values obtained from FT of XRD data agreed well with the histograms from the TEM observations. From FT results, the relative particle size and reducing agent ratio of stabilized Cu NPs showed an inverse correlation. The incomplete reduction of copper ions at lower reducing agent ratios was also confirmed by DSC studies. FT-IR and 2D-IR correlation spectra analysis suggested the first event involved in the stabilization of Cu NPs is their electrostatic interaction with -C=O of carboxylate groups of NaAlg, followed by the interaction with the available O-C-O⁻, and finally with the -OH groups. Bacterial susceptibility to stabilized nanoparticles was found to vary depending on the bacterial strains. The lowest MIC and MBC of stabilized Cu NPs ranged between 2 mg/L and 8 mg/L for all studied strains. Disk-diffusion studies with both E. coli strains revealed greater effectiveness of the stabilized Cu NPs compared to the positive controls (cloxacillin, amoxicillin, and nitrofurantoin). S. aureus showed the highest sensitivity to stabilized Cu NPs compared to the other studied strains. CONCLUSION Cu NPs were successfully synthesized via chemical reduction assisted with microwave heating. Average particle size, polydispersity, and phase composition of Cu NPs depended mainly on the reducing agent ratio. Likewise, thermal stability and antibacterial activity of stabilized Cu NPs were affected by their phase composition. Because of the carboxylate groups in polymer chains, the structural changes of stabilized Cu NPs are different from those of NaAlg. NaAlg acted as a size controller and stabilizing agent of Cu NPs, due to their ability to bind strongly to the metal surface. Our study on the stabilizing agent-dependent structural changes of stabilized NPs is helpful for wide application of NaAlg as an important biopolymer.
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Affiliation(s)
- Judith Díaz-Visurraga
- Department of Pharmacy, Faculty of Pharmacy, University of Concepcion, Concepción, Chile.
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Ciofu O, Mandsberg LF, Wang H, Høiby N. Phenotypes selected during chronic lung infection in cystic fibrosis patients: implications for the treatment ofPseudomonas aeruginosabiofilm infections. ACTA ACUST UNITED AC 2012; 65:215-25. [DOI: 10.1111/j.1574-695x.2012.00983.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 04/23/2012] [Accepted: 04/24/2012] [Indexed: 12/18/2022]
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143
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Ramos AN, Cabral MES, Noseda D, Bosch A, Yantorno OM, Valdez JC. Antipathogenic properties of Lactobacillus plantarum on Pseudomonas aeruginosa: the potential use of its supernatants in the treatment of infected chronic wounds. Wound Repair Regen 2012; 20:552-62. [PMID: 22642376 DOI: 10.1111/j.1524-475x.2012.00798.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 02/27/2012] [Indexed: 11/29/2022]
Abstract
Pathogenic bacteria delay wound healing through several different mechanisms such as persistent production of inflammatory mediators or maintenance of necrotic neutrophils, which release cytolytic enzymes and free oxygen radicals. One of the most frequent pathogens isolated from infections in chronic wounds is Pseudomonas aeruginosa. This bacterium is extremely refractory to therapy and to host immune attack when it forms biofilms. Therefore, antibiotics and antiseptics are becoming useless in the treatment of these infections. In previous works, we demonstrated that Lactobacillus plantarum has an important antipathogenic capacity on P. aeruginosa. The aim of the present work was to elucidate the mechanism involved in the control of growth of P. aeruginosa on different surfaces by L. plantarum. For this purpose, we investigated the effects of L. plantarum supernatants on pathogenic properties of P. aeruginosa, such as adhesion, viability, virulence factors, biofilm formation, and quorum sensing signal expression. L. plantarum supernatants were able to inhibit pathogenic properties of P. aeruginosa by a quorum quenching mechanism. The antipathogenic properties mentioned above, together with the immunomodulatory, tissue repair, and angiogenesis properties in the supernatants of L. plantarum, make them an attractive option in infected chronic wound treatment.
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Affiliation(s)
- Alberto N Ramos
- Cátedra de Inmunología, Instituto de Microbiología, Facultad de Bioquímica, Química y Farmacia de la Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina.
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Correa E, Sletta H, Ellis DI, Hoel S, Ertesvåg H, Ellingsen TE, Valla S, Goodacre R. Rapid reagentless quantification of alginate biosynthesis in Pseudomonas fluorescens bacteria mutants using FT-IR spectroscopy coupled to multivariate partial least squares regression. Anal Bioanal Chem 2012; 403:2591-9. [PMID: 22585056 DOI: 10.1007/s00216-012-6068-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 03/14/2012] [Accepted: 04/19/2012] [Indexed: 11/26/2022]
Abstract
Alginate is an important medical and commercial product and currently is isolated from seaweeds. Certain microorganisms also produce alginate and these polymers have the potential to replace seaweed alginates in some applications, mainly because such production will allow much better and more reproducible control of critical qualitative polymer properties. The research conducted here presents the development of a new approach to this problem by analysing a transposon insertion mutant library constructed in an alginate-producing derivative of the Pseudomonas fluorescens strain SBW25. The procedure is based on the non-destructive and reagent-free method of Fourier transform infrared (FT-IR) spectroscopy which is used to generate a complex biochemical infrared fingerprint of the medium after bacterial growth. First, we investigate the potential differences caused by the growth media fructose and glycerol on the bacterial phenotype and alginate synthesis in 193 selected P. fluorescens mutants and show that clear phenotypic differences are observed in the infrared fingerprints. In order to quantify the level of the alginate we also report the construction and interpretation of multivariate partial least squares regression models which were able to quantify alginate levels successfully with typical normalized root-mean-square error in predictions of only approximately 14%. We have demonstrated that this high-throughput approach can be implemented in alginate screens and we believe that this FT-IR spectroscopic methodology, when combined with the most appropriate chemometrics, could easily be modified for the quantification of other valuable microbial products and play a valuable screening role for synthetic biology.
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Affiliation(s)
- Elon Correa
- School of Chemistry, Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, UK.
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Lu X, Samuelson DR, Rasco BA, Konkel ME. Antimicrobial effect of diallyl sulphide on Campylobacter jejuni biofilms. J Antimicrob Chemother 2012; 67:1915-26. [PMID: 22550133 DOI: 10.1093/jac/dks138] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVES Bacterial biofilms pose significant food safety risks because of their attachment to fomites and food surfaces, including fresh produce surfaces. The purpose of this study was to systematically investigate the activity of selected antimicrobials on Campylobacter jejuni biofilms. METHODS C. jejuni biofilms and planktonic cells were treated with ciprofloxacin, erythromycin and diallyl sulphide and examined using infrared and Raman spectroscopies coupled with imaging analysis. RESULTS Diallyl sulphide eliminated planktonic cells and sessile cells in biofilms at a concentration that was at least 100-fold less than used for either ciprofloxacin or erythromycin on the basis of molarity. Distinct cell lysis was observed in diallyl sulphide-treated planktonic cells using immunoblot analysis and was confirmed by a rapid decrease in cellular ATP. Two phases of C. jejuni biofilm recalcitrance modes against ciprofloxacin and erythromycin were validated using vibrational spectroscopies: (i) an initial hindered adsorption into biofilm extracellular polymeric substance (EPS) and delivery of antibiotics to sessile cells within biofilms; and (ii) a different interaction between sessile cells in a biofilm compared with their planktonic counterparts. Diallyl sulphide destroyed the EPS structure of the C. jejuni biofilm, after which the sessile cells were killed in a similar manner as planktonic cells. Spectroscopic models can predict the survival of sessile cells within biofilms. CONCLUSIONS Diallyl sulphide elicits strong antimicrobial activity against planktonic and sessile C. jejuni and may have applications for reducing the prevalence of this microbe in foods, biofilm reduction and, potentially, as an alternative chemotherapeutic agent for multidrug-resistant bacterial strains.
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Affiliation(s)
- Xiaonan Lu
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7520, USA
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Nowatzki PJ, Koepsel RR, Stoodley P, Min K, Harper A, Murata H, Donfack J, Hortelano ER, Ehrlich GD, Russell AJ. Salicylic acid-releasing polyurethane acrylate polymers as anti-biofilm urological catheter coatings. Acta Biomater 2012; 8:1869-80. [PMID: 22342353 DOI: 10.1016/j.actbio.2012.01.032] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 01/23/2012] [Accepted: 01/26/2012] [Indexed: 01/20/2023]
Abstract
Biofilm-associated infections are a major complication of implanted and indwelling medical devices like urological and venous catheters. They commonly persist even in the presence of an oral or intravenous antibiotic regimen, often resulting in chronic illness. We have developed a new approach to inhibiting biofilm growth on synthetic materials through controlled release of salicylic acid from a polymeric coating. Herein we report the synthesis and testing of a ultraviolet-cured polyurethane acrylate polymer composed, in part, of salicyl acrylate, which hydrolyzes upon exposure to aqueous conditions, releasing salicylic acid while leaving the polymer backbone intact. The salicylic acid release rate was tuned by adjusting the polymer composition. Anti-biofilm performance of the coatings was assessed under several biofilm forming conditions using a novel combination of the MBEC Assay™ biofilm multi-peg growth system and bioluminescence monitoring for live cell quantification. Films of the salicylic acid-releasing polymers were found to inhibit biofilm formation, as shown by bioluminescent and GFP reporter strains of Pseudomonas aeruginosa and Escherichia coli. Urinary catheters coated on their inner lumens with the salicylic acid-releasing polymer significantly reduced biofilm formation by E. coli for up to 5 days under conditions that simulated physiological urine flow.
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Penn AS, Conibear TCR, Watson RA, Kraaijeveld AR, Webb JS. Can Simpson's paradox explain co-operation in Pseudomonas aeruginosa biofilms? ACTA ACUST UNITED AC 2012; 65:226-35. [PMID: 22469426 DOI: 10.1111/j.1574-695x.2012.00970.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 03/28/2012] [Accepted: 03/28/2012] [Indexed: 11/28/2022]
Abstract
Co-operative behaviours, such as the production of public goods, are commonly displayed by bacteria in biofilms and can enhance their ability to survive in environmental or clinical settings. Non-co-operative cheats commonly arise and should, theoretically, disrupt co-operative behaviour. Its stability therefore requires explanation, but no mechanisms to suppress cheating within biofilms have yet been demonstrated experimentally. Theoretically, repeated aggregation into groups, interleaved with dispersal and remixing, can increase co-operation via a 'Simpson's paradox'. That is, an increase in the global proportion of co-operators despite a decrease in within-group proportions, via differential growth of groups. We investigate the hypothesis that microcolony formation and dispersal produces a Simpson's paradox that explains bacterial co-operation in biofilms. Using the production of siderophores in Pseudomonas aeruginosa as our model system for co-operation, we use well-documented co-operator and siderophore-deficient cheat strains to measure the frequency of co-operating and cheating individuals, in-situ within-microcolony structures. We detected significant within-type negative density-dependant effects that vary over microcolony development. However, we find no evidence of Simpson's paradox. Instead, we see clear within-microcolony spatial structure (cheats occupying the interior portions of microcolonies) that may violate the assumption required for Simpson's paradox that group members share equally in the public good.
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Affiliation(s)
- Alexandra S Penn
- Electronics and Computer Science, University of Southampton, Southampton, UK.
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148
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Ma L, Wang J, Wang S, Anderson EM, Lam JS, Parsek MR, Wozniak DJ. Synthesis of multiple Pseudomonas aeruginosa biofilm matrix exopolysaccharides is post-transcriptionally regulated. Environ Microbiol 2012; 14:1995-2005. [PMID: 22513190 DOI: 10.1111/j.1462-2920.2012.02753.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Exopolysaccharide is a critical biofilm matrix component, yet little is known about how the synthesis of multiple exopolysaccharides is regulated. Pseudomonas aeruginosa can produce several biofilm matrix exopolysaccharides that include alginate, Psl and Pel. Here we demonstrated that AlgC, a key enzyme that provides sugar precursors for the synthesis of alginate and lipopolysaccharides (LPS) is also required for both Psl and Pel production. We showed that forced-synthesis of Psl in alginate-producing mucoid bacteria reduced alginate production but this was not due to transcription of the alginate biosynthesis-operon. Likewise, when either alginate or Psl were overproduced, levels of B-band LPS decreased. Induction of Pel resulted in a reduction of Psl levels. Because the effects of reduced exopolysaccharide synthesis when another is overproduced didn't appear to be regulated at the transcriptional level, this suggests that the biosynthesis pathways of Psl, Pel, alginate, and LPS compete for common sugar precursors. As AlgC is the only enzyme that provides precursors for each of these exopolysaccharides, we propose that AlgC is a key checkpoint enzyme that coordinates the total amount of exopolysaccharide biosynthesis by controlling sugar precursor pool. Our data also provide a plausible strategy that P.aeruginosa utilizes to modulate its biofilm matrix exopolysaccharides.
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Affiliation(s)
- Luyan Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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149
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Aujoulat F, Roger F, Bourdier A, Lotthé A, Lamy B, Marchandin H, Jumas-Bilak E. From environment to man: genome evolution and adaptation of human opportunistic bacterial pathogens. Genes (Basel) 2012; 3:191-232. [PMID: 24704914 PMCID: PMC3899952 DOI: 10.3390/genes3020191] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 02/29/2012] [Accepted: 02/29/2012] [Indexed: 02/07/2023] Open
Abstract
Environment is recognized as a huge reservoir for bacterial species and a source of human pathogens. Some environmental bacteria have an extraordinary range of activities that include promotion of plant growth or disease, breakdown of pollutants, production of original biomolecules, but also multidrug resistance and human pathogenicity. The versatility of bacterial life-style involves adaptation to various niches. Adaptation to both open environment and human specific niches is a major challenge that involves intermediate organisms allowing pre-adaptation to humans. The aim of this review is to analyze genomic features of environmental bacteria in order to explain their adaptation to human beings. The genera Pseudomonas, Aeromonas and Ochrobactrum provide valuable examples of opportunistic behavior associated to particular genomic structure and evolution. Particularly, we performed original genomic comparisons among aeromonads and between the strictly intracellular pathogens Brucella spp. and the mild opportunistic pathogens Ochrobactrum spp. We conclude that the adaptation to human could coincide with a speciation in action revealed by modifications in both genomic and population structures. This adaptation-driven speciation could be a major mechanism for the emergence of true pathogens besides the acquisition of specialized virulence factors.
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Affiliation(s)
- Fabien Aujoulat
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Frédéric Roger
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Alice Bourdier
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Anne Lotthé
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Brigitte Lamy
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Hélène Marchandin
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
| | - Estelle Jumas-Bilak
- Université Montpellier 1, UMR 5119 (UM2, CNRS, IRD, IFREMER, UM1), équipe Pathogènes et Environnements, Montpellier 34093, France.
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Ma L, Wang S, Wang D, Parsek MR, Wozniak DJ. The roles of biofilm matrix polysaccharide Psl in mucoid Pseudomonas aeruginosa biofilms. ACTA ACUST UNITED AC 2012; 65:377-80. [PMID: 22309106 DOI: 10.1111/j.1574-695x.2012.00934.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 01/22/2012] [Accepted: 01/27/2012] [Indexed: 12/30/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa causes life-threatening, persistent infections in patients with cystic fibrosis (CF). Persistence is attributed to the ability of these bacteria to form structured communities (biofilms). Biofilms rely on an extracellular polymeric substances matrix to maintain structure. Psl exopolysaccharide is a key matrix component of nonmucoid biofilms, yet the role of Psl in mucoid biofilms is unknown. In this report, using a variety of mutants in a mucoid P. aeruginosa background, we found that deletion of Psl-encoding genes dramatically decreased their biofilm formation ability, indicating that Psl is also a critical matrix component of mucoid biofilms. Our data also suggest that the overproduction of alginate leads to mucoid biofilms, which occupy more space, whereas Psl-dependent biofilms are densely packed. These data suggest that Psl polysaccharide may have significant contributions in biofilm persistence in patients with CF and may be helpful for designing therapies for P. aeruginosa CF infection.
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Affiliation(s)
- Luyan Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
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