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Turbant F, Esnouf E, Rosaz F, Wien F, Węgrzyn G, Chauvet H, Arluison V. Role of the Bacterial Amyloid-like Hfq in Fluoroquinolone Fluxes. Microorganisms 2023; 12:53. [PMID: 38257880 PMCID: PMC10819720 DOI: 10.3390/microorganisms12010053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/22/2023] [Accepted: 12/26/2023] [Indexed: 01/24/2024] Open
Abstract
Due to their two-cell membranes, Gram-negative bacteria are particularly resistant to antibiotics. Recent investigations aimed at exploring new target proteins involved in Gram-negative bacteria adaptation helped to identify environmental changes encountered during infection. One of the most promising approaches in finding novel targets for antibacterial drugs consists of blocking noncoding RNA-based regulation using the protein cofactor, Hfq. Although Hfq is important in many bacterial pathogens, its involvement in antibiotics response is still unclear. Indeed, Hfq may mediate drug resistance by regulating the major efflux system in Escherichia coli, but it could also play a role in the influx of antibiotics. Here, using an imaging approach, we addressed this problem quantitatively at the single-cell level. More precisely, we analyzed how Hfq affects the dynamic influx and efflux of ciprofloxacin, an antibiotic from the group of fluoroquinolones that is used to treat bacterial infections. Our results indicated that the absence of either whole Hfq or its C-terminal domain resulted in a more effective accumulation of ciprofloxacin, irrespective of the presence of the functional AcrAB-TolC efflux pump. However, overproduction of the MicF small regulatory RNA, which reduces the efficiency of expression of the ompF gene (coding for a porin involved in antibiotics influx) in a Hfq-dependent manner, resulted in impaired accumulation of ciprofloxacin. These results led us to propose potential mechanisms of action of Hfq in the regulation of fluoroquinolone fluxes across the E. coli envelope.
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Affiliation(s)
- Florian Turbant
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France; (F.T.); (F.W.); (H.C.)
- Laboratoire Léon Brillouin LLB, UMR12 CEA CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France; (E.E.); (F.R.)
- Department of Molecular Biology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Emeline Esnouf
- Laboratoire Léon Brillouin LLB, UMR12 CEA CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France; (E.E.); (F.R.)
| | - Francois Rosaz
- Laboratoire Léon Brillouin LLB, UMR12 CEA CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France; (E.E.); (F.R.)
| | - Frank Wien
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France; (F.T.); (F.W.); (H.C.)
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Hugo Chauvet
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France; (F.T.); (F.W.); (H.C.)
| | - Véronique Arluison
- Laboratoire Léon Brillouin LLB, UMR12 CEA CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France; (E.E.); (F.R.)
- UFR SDV, Université Paris Cité, 75013 Paris, France
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2
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Geraldes C, Tavares L, Gil S, Oliveira M. Biocides in the Hospital Environment: Application and Tolerance Development. Microb Drug Resist 2023; 29:456-476. [PMID: 37643289 DOI: 10.1089/mdr.2023.0074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023] Open
Abstract
Hospital-acquired infections are a rising problem with consequences for patients, hospitals, and health care workers. Biocides can be employed to prevent these infections, contributing to eliminate or reduce microorganisms' concentrations at the hospital environment. These antimicrobials belong to several groups, each with distinct characteristics that need to be taken into account in their selection for specific applications. Moreover, their activity is influenced by many factors, such as compound concentration and the presence of organic matter. This article aims to review some of the chemical biocides available for hospital infection control, as well as the main factors that influence their efficacy and promote susceptibility decreases, with the purpose to contribute for reducing misusage and consequently for preventing the development of resistance to these antimicrobials.
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Affiliation(s)
- Catarina Geraldes
- Department of Animal Health, Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), Lisbon, Portugal
| | - Luís Tavares
- Department of Animal Health, Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), Lisbon, Portugal
| | - Solange Gil
- Department of Animal Health, Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), Lisbon, Portugal
- Department of Animal Health, Biological Isolation and Containment Unit (BICU), Veterinary Hospital, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Manuela Oliveira
- Department of Animal Health, Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), Lisbon, Portugal
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3
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Hall MB, Lima L, Coin LJM, Iqbal Z. Drug resistance prediction for Mycobacterium tuberculosis with reference graphs. Microb Genom 2023; 9:mgen001081. [PMID: 37552534 PMCID: PMC10483414 DOI: 10.1099/mgen.0.001081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/14/2023] [Indexed: 08/09/2023] Open
Abstract
Tuberculosis is a global pandemic disease with a rising burden of antimicrobial resistance. As a result, the World Health Organization (WHO) has a goal of enabling universal access to drug susceptibility testing (DST). Given the slowness of and infrastructure requirements for phenotypic DST, whole-genome sequencing, followed by genotype-based prediction of DST, now provides a route to achieving this. Since a central component of genotypic DST is to detect the presence of any known resistance-causing mutations, a natural approach is to use a reference graph that allows encoding of known variation. We have developed DrPRG (Drug resistance Prediction with Reference Graphs) using the bacterial reference graph method Pandora. First, we outline the construction of a Mycobacterium tuberculosis drug resistance reference graph. The graph is built from a global dataset of isolates with varying drug susceptibility profiles, thus capturing common and rare resistance- and susceptible-associated haplotypes. We benchmark DrPRG against the existing graph-based tool Mykrobe and the haplotype-based approach of TBProfiler using 44 709 and 138 publicly available Illumina and Nanopore samples with associated phenotypes. We find that DrPRG has significantly improved sensitivity and specificity for some drugs compared to these tools, with no significant decreases. It uses significantly less computational memory than both tools, and provides significantly faster runtimes, except when runtime is compared to Mykrobe with Nanopore data. We discover and discuss novel insights into resistance-conferring variation for M. tuberculosis - including deletion of genes katG and pncA - and suggest mutations that may warrant reclassification as associated with resistance.
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Affiliation(s)
- Michael B. Hall
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridgeshire, UK
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia
| | - Leandro Lima
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridgeshire, UK
| | - Lachlan J. M. Coin
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia
| | - Zamin Iqbal
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridgeshire, UK
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4
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Goswami AG, Basu S, Banerjee T, Shukla VK. Biofilm and wound healing: from bench to bedside. Eur J Med Res 2023; 28:157. [PMID: 37098583 PMCID: PMC10127443 DOI: 10.1186/s40001-023-01121-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 04/14/2023] [Indexed: 04/27/2023] Open
Abstract
The bubbling community of microorganisms, consisting of diverse colonies encased in a self-produced protective matrix and playing an essential role in the persistence of infection and antimicrobial resistance, is often referred to as a biofilm. Although apparently indolent, the biofilm involves not only inanimate surfaces but also living tissue, making it truly ubiquitous. The mechanism of biofilm formation, its growth, and the development of resistance are ever-intriguing subjects and are yet to be completely deciphered. Although an abundance of studies in recent years has focused on the various ways to create potential anti-biofilm and antimicrobial therapeutics, a dearth of a clear standard of clinical practice remains, and therefore, there is essentially a need for translating laboratory research to novel bedside anti-biofilm strategies that can provide a better clinical outcome. Of significance, biofilm is responsible for faulty wound healing and wound chronicity. The experimental studies report the prevalence of biofilm in chronic wounds anywhere between 20 and 100%, which makes it a topic of significant concern in wound healing. The ongoing scientific endeavor to comprehensively understand the mechanism of biofilm interaction with wounds and generate standardized anti-biofilm measures which are reproducible in the clinical setting is the challenge of the hour. In this context of "more needs to be done", we aim to explore various effective and clinically meaningful methods currently available for biofilm management and how these tools can be translated into safe clinical practice.
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Affiliation(s)
| | - Somprakas Basu
- All India Institute of Medical Sciences, Rishikesh, 249203, India.
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5
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Biocompatible Polymer Materials with Antimicrobial Properties for Preparation of Stents. NANOMATERIALS 2019; 9:nano9111548. [PMID: 31683612 PMCID: PMC6915381 DOI: 10.3390/nano9111548] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/15/2019] [Accepted: 10/29/2019] [Indexed: 12/17/2022]
Abstract
Biodegradable polymers are promising materials for use in medical applications such as stents. Their properties are comparable to commercially available resistant metal and polymeric stents, which have several major problems, such as stent migration and stent clogging due to microbial biofilm. Consequently, conventional stents have to be removed operatively from the patient's body, which presents a number of complications and can also endanger the patient's life. Biodegradable stents disintegrate into basic substances that decompose in the human body, and no surgery is required. This review focuses on the specific use of stents in the human body, the problems of microbial biofilm, and possibilities of preventing microbial growth by modifying polymers with antimicrobial agents.
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Preda VG, Săndulescu O. Communication is the key: biofilms, quorum sensing, formation and prevention. Discoveries (Craiova) 2019; 7:e100. [PMID: 32309618 PMCID: PMC7086079 DOI: 10.15190/d.2019.13] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 09/29/2019] [Accepted: 09/29/2019] [Indexed: 12/19/2022] Open
Abstract
Antibiotic resistance is a relevant topic nowadays, representing one of the main causes of infection-related mortality and morbidity at a global level. This phenomenon is worrisome and represents an area of interest for both clinical practice and fundamental research. One important mechanism whereby bacteria acquire resistance to antibiotics and evade the immune system is by forming biofilms. It is estimated that ~80% of the bacteria producing chronic infections can form biofilms. During the process of biofilm formation microorganisms have the ability to communicate with each other through quorum sensing. Quorum sensing regulates the metabolic activity of planktonic cells, and it can induce microbial biofilm formation and increased virulence. In this review we describe the biofilm formation process, quorum sensing, quorum quenching, several key infectious bacteria producing biofilm, methods of prevention and their challenges and limitations. Although progress has been made in the prevention and treatment of biofilm-driven infections, new strategies are required and have to be further developed.
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Affiliation(s)
- Veronica G. Preda
- Department of Biochemistry and Molecular Biology, University of Bucharest, Faculty of Biology, Bucharest, Romania
- Department of Genetics and Applied Biotechnology, University of Bucharest, Faculty of Biology, Bucharest, Romania
| | - Oana Săndulescu
- Department of Infectious Diseases I, Carol Davila University of Medicine and Pharmacy, National Institute for Infectious Diseases “Prof. Dr. Matei Balș”, Bucharest, Romania
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7
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Marques CNH, Nelson SM. Pharmacodynamics of ciprofloxacin against Pseudomonas aeruginosa planktonic and biofilm-derived cells. Lett Appl Microbiol 2019; 68:350-359. [PMID: 30740751 DOI: 10.1111/lam.13126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 02/05/2019] [Accepted: 02/06/2019] [Indexed: 02/03/2023]
Abstract
The influence of growth phase and state on the survival and recovery of Pseudomonas aeruginosa exposed to ciprofloxacin was investigated using batch culture grown planktonic cells and disaggregated biofilm populations. Biofilms were either nonantibiotic exposed or previously exposed to ciprofloxacin before disaggregation and subsequent challenge with ciprofloxacin. Viable counts showed that late stationary phase cells were tolerant to ciprofloxacin over 24 h exposure, while all other populations presented a biphasic killing pattern. In contrast, the metabolic activity of planktonic and biofilm-derived cells remained similar to controls during the initial 6 h of ciprofloxacin exposure, despite a significant reduction in viable cell numbers. A similar effect was observed when assessing the postantibiotic effect of 1 h ciprofloxacin exposure. Thus, although cell reduction occurred, the metabolic status of the cells remained unchanged. The recovery of disaggregated biofilm cells previously exposed to ciprofloxacin was significantly quicker than naïve biofilm cells, and this latter population's recovery was significantly slower than all planktonic populations. Results from this work have implications for our understanding of biofilm-related infections and their resilience to antimicrobial treatment. SIGNIFICANCE AND IMPACT OF THE STUDY: Removal of biofilms from surfaces and infection sites via disaggregation and induction of dispersion may reverse their antibiotic tolerant state. However, little is known of the recovery of the cells upon disaggregation from biofilms. Driven by this gap in knowledge we quantified the effect of ciprofloxacin on disaggregated biofilms of Pseudomonas aeruginosa, including those previously exposed to ciprofloxacin. Our results provide further insight into bacterial resilience, regrowth, and antimicrobial efficacy, as reduction in cell viability does not directly correlate with the metabolic activity of bacteria at the time of the exposure to antimicrobials. Thus, despite a perceived reduction in viability, the potential for cell persistence and regrowth remains and recovery is quicker upon subsequent exposure to antimicrobial, supporting the increase in resilience and recurrence of infections.
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Affiliation(s)
- C N H Marques
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA.,Binghamton Biofilm Research Center (BBRC), Binghamton University, Binghamton, NY, USA
| | - S M Nelson
- Department of Applied Sciences, Faculty of Health and Applied Sciences, University of the West of England, Bristol, UK
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8
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Türkel İ, Yıldırım T, Yazgan B, Bilgin M, Başbulut E. Relationship between antibiotic resistance, efflux pumps, and biofilm formation in extended-spectrum β-lactamase producing Klebsiella pneumoniae. J Chemother 2019; 30:354-363. [DOI: 10.1080/1120009x.2018.1521773] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- İbrahim Türkel
- Department of Biology, Faculty of Arts and Sciences, Amasya University, Amasya, Turkey,
| | - Tuba Yıldırım
- Department of Biology, Faculty of Arts and Sciences, Amasya University, Amasya, Turkey,
- Central Research Laboratory, Amasya University, Amasya, Turkey,
| | - Burak Yazgan
- Central Research Laboratory, Amasya University, Amasya, Turkey,
- Department of Medical Sevices and Techniques, Amasya University Sabuncuoğlu Serefeddin Vocational Higher School of Health Services, Amasya, Turkey,
| | - Melek Bilgin
- Microbiology Laboratory, Education and Research Hospital, Samsun, Turkey
| | - Eşe Başbulut
- Microbiology Laboratory, Education and Research Hospital, Samsun, Turkey
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9
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Evaluation of Acquired Antibiotic Resistance in Escherichia coli Exposed to Long-Term Low-Shear Modeled Microgravity and Background Antibiotic Exposure. mBio 2019; 10:mBio.02637-18. [PMID: 30647159 PMCID: PMC6336426 DOI: 10.1128/mbio.02637-18] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Stress factors experienced during space include microgravity, sleep deprivation, radiation, isolation, and microbial contamination, all of which can promote immune suppression (1, 2). Under these conditions, the risk of infection from opportunistic pathogens increases significantly, particularly during long-term missions (3). If infection occurs, it is important that the infectious agent should not be antibiotic resistant. Minimizing the occurrence of antibiotic resistance is, therefore, highly desirable. To facilitate this, it is important to better understand the long-term response of bacteria to the microgravity environment. This study demonstrated that the use of antibiotics as a preventive measure could be counterproductive and would likely result in persistent resistance to that antibiotic. In addition, unintended resistance to other antimicrobials might also occur as well as permanent genome changes that might have other unanticipated and undesirable consequences. The long-term response of microbial communities to the microgravity environment of space is not yet fully understood. Of special interest is the possibility that members of these communities may acquire antibiotic resistance. In this study, Escherichia coli cells were grown under low-shear modeled microgravity (LSMMG) conditions for over 1,000 generations (1000G) using chloramphenicol treatment between cycles to prevent contamination. The results were compared with data from an earlier control study done under identical conditions using steam sterilization between cycles rather than chloramphenicol. The sensitivity of the final 1000G-adapted strain to a variety of antibiotics was determined using Vitek analysis. In addition to resistance to chloramphenicol, the adapted strain acquired resistance to cefalotin, cefuroxime, cefuroxime axetil, cefoxitin, and tetracycline. In fact, the resistance to chloramphenicol and cefalotin persisted for over 110 generations despite the removal of both LSMMG conditions and trace antibiotic exposure. Genome sequencing of the adapted strain revealed 22 major changes, including 3 transposon-mediated rearrangements (TMRs). Two TMRs disrupted coding genes (involved in bacterial adhesion), while the third resulted in the deletion of an entire segment (14,314 bp) of the genome, which includes 14 genes involved with motility and chemotaxis. These results are in stark contrast with data from our earlier control study in which cells grown under the identical conditions without antibiotic exposure never acquired antibiotic resistance. Overall, LSMMG does not appear to alter the antibiotic stress resistance seen in microbial ecosystems not exposed to microgravity.
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10
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González Ocampo JI, Bassous N, Ossa Orozco CP, Webster TJ. Evaluation of cytotoxicity and antimicrobial activity of an injectable bone substitute of carrageenan and nano hydroxyapatite. J Biomed Mater Res A 2018; 106:2984-2993. [PMID: 30367558 DOI: 10.1002/jbm.a.36488] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/16/2018] [Accepted: 06/11/2018] [Indexed: 01/27/2023]
Abstract
A successful post-surgical implant is associated with accelerated recovery periods, involving the efficient regeneration of lost or non-viable tissue and a reduction in microbial growth. Alternatively, the long-term success of an implant is guided by the selection of an engineered biomimetic material that is biocompatible, non-biodegradable, and stable at the site of implantation, without invoking any non-essential or undesirable biological responses. The potential for developing an injectable bone substitute (IBS) was investigated here. In particular, carrageenan (CG) and nano-hydroxyapatite (nHA) injectable composites were fabricated by chemical cross-linking, and the in vitro behavior of mammalian cells and bacteria on the IBS surface structures were evaluated. Formulations consisting of 1%, 1.5%, and 2.5% CG and 60% nHA by weight were then evaluated for their interactions with human osteoblasts (or bone forming cells). MTS viability testing indicated that osteoblast adhesion and viability on the IBS were excellent and uniform among various formulation types. Bacteria assays were also performed to assess antimicrobial functions on the CG/nHA composite against both Gram-negative and Gram-positive strains. A higher CG content, as found in some samples, correlated with improved Pseudomonas aeruginosa growth inhibition, although other bacteria strains appeared unaffected by the IBS. In summary, this study highlights CG/nHA composites as innovative biomaterials that should be further studied for reduced bacteria activity and promoted osteoblast responses which was achieved without using pharmaceutical drugs. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2984-2993, 2018.
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Affiliation(s)
- Jazmín I González Ocampo
- Biomaterials Research Group, Bioengineering Program, Engineering Faculty, University of Antioquia, Medellin, Colombia
| | - Nicole Bassous
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts
| | - Claudia P Ossa Orozco
- Biomaterials Research Group, Bioengineering Program, Engineering Faculty, University of Antioquia, Medellin, Colombia
| | - Thomas J Webster
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts
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11
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Kiu R, Caim S, Alcon-Giner C, Belteki G, Clarke P, Pickard D, Dougan G, Hall LJ. Preterm Infant-Associated Clostridium tertium, Clostridium cadaveris, and Clostridium paraputrificum Strains: Genomic and Evolutionary Insights. Genome Biol Evol 2018; 9:2707-2714. [PMID: 29044436 PMCID: PMC5647805 DOI: 10.1093/gbe/evx210] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2017] [Indexed: 01/14/2023] Open
Abstract
Clostridium species (particularly Clostridium difficile, Clostridium botulinum, Clostridium tetani and Clostridium perfringens) are associated with a range of human and animal diseases. Several other species including Clostridium tertium, Clostridium cadaveris, and Clostridium paraputrificum have also been linked with sporadic human infections, however there is very limited, or in some cases, no genomic information publicly available. Thus, we isolated one C. tertium strain, one C. cadaveris strain and three C. paraputrificum strains from preterm infants residing within neonatal intensive care units and performed Whole Genome Sequencing (WGS) using Illumina HiSeq. In this report, we announce the open availability of the draft genomes: C. tertium LH009, C. cadaveris LH052, C. paraputrificum LH025, C. paraputrificum LH058, and C. paraputrificum LH141. These genomes were checked for contamination in silico to ensure purity, and we confirmed species identity and phylogeny using both 16S rRNA gene sequences (from PCR and in silico) and WGS-based approaches. Average Nucleotide Identity (ANI) was used to differentiate genomes from their closest relatives to further confirm speciation boundaries. We also analysed the genomes for virulence-related factors and antimicrobial resistance genes, and detected presence of tetracycline and methicillin resistance, and potentially harmful enzymes, including multiple phospholipases and toxins. The availability of genomic data in open databases, in tandem with our initial insights into the genomic content and virulence traits of these pathogenic Clostridium species, should enable the scientific community to further investigate the disease-causing mechanisms of these bacteria with a view to enhancing clinical diagnosis and treatment.
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Affiliation(s)
- Raymond Kiu
- The Gut Health and Food Safety Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, United Kingdom.,Norwich Medical School, Norwich Research Park, University of East Anglia, Norwich, United Kingdom
| | - Shabhonam Caim
- The Gut Health and Food Safety Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, United Kingdom
| | - Cristina Alcon-Giner
- The Gut Health and Food Safety Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, United Kingdom
| | - Gusztav Belteki
- Neonatal Intensive Care Unit, The Rosie Hospital, Cambridge University Hospitals NHS Foundation Trust, United Kingdom
| | - Paul Clarke
- Neonatal Intensive Care Unit, Norfolk and Norwich University Hospitals NHS Foundation Trust, Norwich, United Kingdom
| | - Derek Pickard
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Lindsay J Hall
- The Gut Health and Food Safety Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, United Kingdom
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12
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Li W, Zhang S, Wang X, Yu J, Li Z, Lin W, Lin X. Systematically integrated metabonomic-proteomic studies of Escherichia coli under ciprofloxacin stress. J Proteomics 2018. [PMID: 29522880 DOI: 10.1016/j.jprot.2018.03.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Many antibiotics are used to kill pathogenic Escherichia coli each year, resulting in an increase in the number of antibiotic-resistant strains. In this study, an integrated metabonomic-proteomic method was performed to systematically compare the profiles of metabolites and proteins with or without ciprofloxacin (CFLX) treatment. Proteomics identified 290 altered proteins including 143 with decreased and 147 increased expression, respectively. Metabonomics identified 65 altered metabolites including 58 and 7 with decreased and increased expression, respectively. The integrated analysis showed that the CFLX inhibited the DNA replication and increased the expression of DNA gyrase and DNA topoisomerase 1, while causing a sharp decrease in metabolic activity such as the alanine, aspartate and glutamate metabolism. Moreover, CFLX affected the biosynthesis of aminoacyl- transfer RNAs (tRNAs), leading to an increase in aminoacyl-tRNAs ligases, but limited the aminoacyl-tRNAs-mediated-biosynthesis of related amino acids. In this study, we identified the metabolite and protein profiles under CFLX stress, indicating the mode of action of antibiotics in E. coli. Furthermore, the decreasing metabolic activity in E. coli may be an effective strategy to escape killing by antimicrobials or toxic compounds. The results of this study will advance our understanding of the mechanisms underlying the resistance of bacteria to antibiotics. BIOLOGICAL SIGNIFICANCE To investigate the biological impact of antibiotics stress on Escherichia coli, we applied an integrated metabonomic-proteomic method to systematically compare the profiles of metabolites and proteins between with and without antibiotics ciprofloxacin (CFLX) treatment. Following bioinformatics analysis showed that CFLX inhibited the DNA replication and increased the expression of DNA gyrase and DNA topoisomerase, while causing a sharp increase in the alanine, aspartate and glutamate metabolism. Moreover, CFLX affected the biosynthesis of tRNAs and limited the generation of related amino acids metabolites. In a summary, our results will provide the metabolite and protein profiles under CFLX stress, indicating the mode of action of antibiotics in E. coli. The results of this study will advance our understanding of the mechanisms underlying the resistance of bacteria to antibiotics.
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Affiliation(s)
- Wanxin Li
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, PR China; Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou 35002, PR China
| | - Song Zhang
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, PR China
| | - Xiaoyun Wang
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, PR China; Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou 35002, PR China
| | - Jing Yu
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, PR China; Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou 35002, PR China
| | - Zeqi Li
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, PR China; Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou 35002, PR China
| | - Wenxiong Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, PR China; Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou 35002, PR China
| | - Xiangmin Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, PR China; Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou 35002, PR China.
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13
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Abstract
Over half of the nearly two million healthcare-associated infections can be attributed to indwelling medical devices. In this review, we highlight the difficulty in diagnosing implantable device-related infection and how this leads to a likely underestimate of the prevalence. We then provide a length-scale conceptualization of device-related infection pathogenesis. Within this conceptualization we focus specifically on biofilm formation and the role of host immune and coagulation systems. Using this framework, we describe how current and developing preventative strategies target specific processes along the entire length-scale. In light of the significant time horizon for the development and translation of new preventative technologies, we also emphasize the need for parallel development of in situ treatment strategies. Specific examples of both preventative and treatment strategies and how they align with the length-scale conceptualization are described.
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Singh S, Singh SK, Chowdhury I, Singh R. Understanding the Mechanism of Bacterial Biofilms Resistance to Antimicrobial Agents. Open Microbiol J 2017; 11:53-62. [PMID: 28553416 PMCID: PMC5427689 DOI: 10.2174/1874285801711010053] [Citation(s) in RCA: 358] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/15/2017] [Accepted: 02/15/2017] [Indexed: 01/08/2023] Open
Abstract
A biofilm is a group of microorganisms, that causes health problems for the patients with indwelling medical devices via attachment of cells to the surface matrix. It increases the resistance of a microorganism for antimicrobial agents and developed the human infection. Current strategies are removed or prevent the microbial colonies from the medical devices, which are attached to the surfaces. This will improve the clinical outcomes in favor of the patients suffering from serious infectious diseases. Moreover, the identification and inhibition of genes, which have the major role in biofilm formation, could be the effective approach for health care systems. In a current review article, we are highlighting the biofilm matrix and molecular mechanism of antimicrobial resistance in bacterial biofilms.
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Affiliation(s)
- Shriti Singh
- Department of Kriya Sharir, Institute of Medical Sciences, Banaras Hindu University, Varanasi- 221 005 UP India
| | - Santosh Kumar Singh
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Indrajit Chowdhury
- Department of Obstetrics and Gynecology; Morehouse School of Medicine, Atlanta, GA, USA
| | - Rajesh Singh
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
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15
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Bay DC, Stremick CA, Slipski CJ, Turner RJ. Secondary multidrug efflux pump mutants alter Escherichia coli biofilm growth in the presence of cationic antimicrobial compounds. Res Microbiol 2016; 168:208-221. [PMID: 27884783 DOI: 10.1016/j.resmic.2016.11.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 11/07/2016] [Accepted: 11/08/2016] [Indexed: 11/30/2022]
Abstract
Escherichia coli possesses many secondary active multidrug resistance transporters (MDTs) that confer overlapping substrate resistance to a broad range of antimicrobials via proton and/or sodium motive force. It is uncertain whether redundant MDTs uniquely alter cell survival when cultures grow planktonically or as biofilms. In this study, the planktonic and biofilm growth and antimicrobial resistance of 13 E. coli K-12 single MDT gene deletion strains in minimal and rich media were determined. Antimicrobial tolerance to tetracycline, tobramycin and benzalkonium were also compared for each ΔMDT strain. Four E. coli MDT families were represented in this study: resistance nodulation and cell division members acrA, acrB, acrD, acrE, acrF and tolC; multidrug and toxin extruder mdtK; major facilitator superfamily emrA and emrB; and small multidrug resistance members emrE, sugE, mdtI and mdtJ. Deletions of multipartite efflux system genes acrB, acrE and tolC resulted in significant reductions in both planktonic and biofilm growth phenotypes and enhanced antimicrobial susceptibilities. The loss of remaining MDT genes produced similar or enhanced (acrD, acrE, emrA, emrB, mdtK, emrE and mdtJ) biofilm growth and antimicrobial resistance. ΔMDT strains with enhanced antimicrobial tolerance also enhanced biofilm biomass. These findings suggest that many redundant MDTs regulate biofilm formation and drug tolerance.
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Affiliation(s)
- Denice C Bay
- University of Manitoba, Department of Medical Microbiology and Infectious Diseases, Winnipeg, Manitoba, Canada.
| | - Carol A Stremick
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Carmine J Slipski
- University of Manitoba, Department of Medical Microbiology and Infectious Diseases, Winnipeg, Manitoba, Canada
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
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16
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Rao V, Ghei R, Chambers Y. Biofilms Research—Implications to Biosafety and Public Health. APPLIED BIOSAFETY 2016. [DOI: 10.1177/153567600501000205] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Venkat Rao
- Computer Sciences Corporation, Rockville, Maryland
| | - Rashmi Ghei
- Computer Sciences Corporation, Rockville, Maryland
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17
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Zhou G, Shi QS, Huang XM, Xie XB. The Three Bacterial Lines of Defense against Antimicrobial Agents. Int J Mol Sci 2015; 16:21711-33. [PMID: 26370986 PMCID: PMC4613276 DOI: 10.3390/ijms160921711] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 08/21/2015] [Accepted: 08/31/2015] [Indexed: 01/06/2023] Open
Abstract
Antimicrobial agents target a range of extra- and/or intracellular loci from cytoplasmic wall to membrane, intracellular enzymes and genetic materials. Meanwhile, many resistance mechanisms employed by bacteria to counter antimicrobial agents have been found and reported in the past decades. Based on their spatially distinct sites of action and distribution of location, antimicrobial resistance mechanisms of bacteria were categorized into three groups, coined the three lines of bacterial defense in this review. The first line of defense is biofilms, which can be formed by most bacteria to overcome the action of antimicrobial agents. In addition, some other bacteria employ the second line of defense, the cell wall, cell membrane, and encased efflux pumps. When antimicrobial agents permeate the first two lines of defense and finally reach the cytoplasm, many bacteria will make use of the third line of defense, including alterations of intracellular materials and gene regulation to protect themselves from harm by bactericides. The presented three lines of defense theory will help us to understand the bacterial resistance mechanisms against antimicrobial agents and design efficient strategies to overcome these resistances.
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Affiliation(s)
- Gang Zhou
- Guangdong Institute of Microbiology, Guangzhou 510070, Guangdong, China.
- State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, Guangdong, China.
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou 510070, Guangdong, China.
| | - Qing-Shan Shi
- Guangdong Institute of Microbiology, Guangzhou 510070, Guangdong, China.
- State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, Guangdong, China.
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou 510070, Guangdong, China.
| | - Xiao-Mo Huang
- Guangdong Institute of Microbiology, Guangzhou 510070, Guangdong, China.
- State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, Guangdong, China.
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou 510070, Guangdong, China.
| | - Xiao-Bao Xie
- Guangdong Institute of Microbiology, Guangzhou 510070, Guangdong, China.
- State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, Guangdong, China.
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou 510070, Guangdong, China.
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18
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Schlisselberg DB, Kler E, Kisluk G, Shachar D, Yaron S. Biofilm formation ability of Salmonella enterica serovar Typhimurium acrAB mutants. Int J Antimicrob Agents 2015; 46:456-9. [PMID: 26260191 DOI: 10.1016/j.ijantimicag.2015.06.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 05/04/2015] [Accepted: 06/14/2015] [Indexed: 10/23/2022]
Abstract
Recent studies offer contradictory findings about the role of multidrug efflux pumps in bacterial biofilm development. Thus, the aim of this study was to investigate the involvement of the AcrAB efflux pump in biofilm formation by investigating the ability of AcrB and AcrAB null mutants of Salmonella enterica serovar Typhimurium to produce biofilms. Three models were used to compare the ability of S. Typhimurium wild-type and its mutants to form biofilms: formation of biofilm on polystyrene surfaces; production of biofilm (mat model) on the air/liquid interface; and expression of curli and cellulose on Congo red-supplemented agar plates. All three investigated genotypes formed biofilms with similar characteristics. However, upon exposure to chloramphenicol, formation of biofilms on solid surfaces as well as the production of curli were either reduced or were delayed more significantly in both mutants, whilst there was no visible effect on pellicle formation. It can be concluded that when no selective pressure is applied, S. Typhimurium is able to produce biofilms even when the AcrAB efflux pumps are inactivated, implying that the use of efflux pump inhibitors to prevent biofilm formation is not a general solution and that combined treatments might be more efficient. Other factors that affect the ability to produce biofilms depending on efflux pump activity are yet to be identified.
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Affiliation(s)
- Dov B Schlisselberg
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Edna Kler
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Guy Kisluk
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Dina Shachar
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Sima Yaron
- Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
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19
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Alam AKMM, Shubhra QTH. Surface modified thin film from silk and gelatin for sustained drug release to heal wound. J Mater Chem B 2015; 3:6473-6479. [DOI: 10.1039/c5tb00920k] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A thin film was prepared from silk and gelatin and the surface was modified. The drug-loaded surface-modified film showed sustained drug release and enhanced wound healing in the rat model.
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Affiliation(s)
- A. K. M. Moshiul Alam
- Institute of Radiation and Polymer Technology
- Bangladesh Atomic Energy Commission
- Dhaka 1207
- Bangladesh
| | - Quazi T. H. Shubhra
- Institute of Radiation and Polymer Technology
- Bangladesh Atomic Energy Commission
- Dhaka 1207
- Bangladesh
- Nanosystem Research Institute
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20
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Wilkins M, Hall-Stoodley L, Allan RN, Faust SN. New approaches to the treatment of biofilm-related infections. J Infect 2014; 69 Suppl 1:S47-52. [DOI: 10.1016/j.jinf.2014.07.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2014] [Indexed: 10/24/2022]
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21
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Duval V, Lister IM. MarA, SoxS and Rob of Escherichia coli - Global regulators of multidrug resistance, virulence and stress response. ACTA ACUST UNITED AC 2013; 2:101-124. [PMID: 24860636 DOI: 10.6000/1927-3037.2013.02.03.2] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Bacteria have a great capacity for adjusting their metabolism in response to environmental changes by linking extracellular stimuli to the regulation of genes by transcription factors. By working in a co-operative manner, transcription factors provide a rapid response to external threats, allowing the bacteria to survive. This review will focus on transcription factors MarA, SoxS and Rob in Escherichia coli, three members of the AraC family of proteins. These homologous proteins exemplify the ability to respond to multiple threats such as oxidative stress, drugs and toxic compounds, acidic pH, and host antimicrobial peptides. MarA, SoxS and Rob recognize similar DNA sequences in the promoter region of more than 40 regulatory target genes. As their regulons overlap, a finely tuned adaptive response allows E. coli to survive in the presence of different assaults in a co-ordinated manner. These regulators are well conserved amongst Enterobacteriaceae and due to their broad involvement in bacterial adaptation in the host, have recently been explored as targets to develop new anti-virulence agents. The regulators are also being examined for their roles in novel technologies such as biofuel production.
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Affiliation(s)
- Valérie Duval
- Center for Adaptation Genetics and Drug Resistance, Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111
| | - Ida M Lister
- Arietis Corporation, 650 Albany Street, Room 130, Boston, MA 02118
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22
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Percival SL, Malic S, Cruz H, Williams DW. Introduction to Biofilms. SPRINGER SERIES ON BIOFILMS 2011. [DOI: 10.1007/978-3-642-21289-5_2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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McCann MT, Gilmore BF, Gorman SP. Staphylococcus epidermidis device-related infections: pathogenesis and clinical management. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.60.12.0001] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Staphylococcus epidermidis, the most frequently isolated coagulase-negative staphylococcus, is the leading cause of infection related to implanted medical devices (IMDs). This is directly related to its capability to establish multilayered, highly structured biofilms on artificial surfaces. At present, conventional systemic therapies using standard antimicrobial agents represent the main strategy to treat and prevent medical device-associated infections. However, device-related infections are notoriously difficult to treat and bacteria within biofilm communities on the surface of IMDs frequently outlive treatment, and removal of the medical device is often required for successful therapy. Importantly, major advances in this research area have been made, leading to a greater understanding of the complexities of biofilm formation of S. epidermidis and resulting in significant developments in the treatment and prevention of infections related to this member of the coagulase-negative group of staphylococci. This review will examine the pathogenesis of the clinically significant S. epidermidis and provide an overview of the conventional and emerging antibiofilm approaches in the management of medical device-associated infections related to this important nosocomial pathogen.
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Affiliation(s)
- Maureen T McCann
- Maureen McCann, Brendan Gilmore, Sean Gorman: Queens University of Belfast, School of Pharmacy, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Brendan F Gilmore
- Maureen McCann, Brendan Gilmore, Sean Gorman: Queens University of Belfast, School of Pharmacy, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Sean P Gorman
- Maureen McCann, Brendan Gilmore, Sean Gorman: Queens University of Belfast, School of Pharmacy, 97 Lisburn Road, Belfast BT9 7BL, UK
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24
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Noreddin AM, Elkhatib WF. Novel in vitro pharmacodynamic model simulating ofloxacin pharmacokinetics in the treatment of Pseudomonas aeruginosa biofilm-associated infections. J Infect Public Health 2009; 2:120-8. [PMID: 20701871 DOI: 10.1016/j.jiph.2009.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 07/26/2009] [Accepted: 07/30/2009] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES The conventional in vitro models simulate pharmacodynamics of antibiotics in the treatment of planktonic Pseudomonas aeruginosa. In this study, we propose a novel pharmacodynamic model of ofloxacin activity in the treatment of P. aeruginosa biofilm. METHODS P. aeruginosa biofilm carrying coupons were suspended in a continuous flow central compartment bioreactor (CCB). In the CCB, the pharmacokinetics of different ofloxacin dosing regimens were simulated. Samples from the coupons and the CCB were assessed for viability of the biofilm and the shedding planktonic cells, respectively, over 24h. In addition, ofloxacin concentrations were assessed in each sample withdrawn for the CCB using bioassay method. RESULTS The microbiological outcomes on P. aeruginosa biofilm and the shedding planktonic cells in response to different ofloxacin dosing regimens were not parallel and this may explain the non-coincidence of microbiological and clinical outcomes with biofilm associated infections. CONCLUSION The current study has introduced unprecedented novel dynamic model for the assessment of the microbiological outcome on both biofilm and shedding planktonic cells of P. aeruginosa in response to different dosing regimens of ofloxacin which in turn can simulate the clinical outcomes in biofilm associated infections of P. aeruginosa, e.g. cystic fibrosis. Furthermore, different scenarios of antibiotic dosing regimens against biofilm related infections can be mimicked using such model.
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25
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Abstract
Drug efflux pumps play a key role in drug resistance and also serve other functions in bacteria. There has been a growing list of multidrug and drug-specific efflux pumps characterized from bacteria of human, animal, plant and environmental origins. These pumps are mostly encoded on the chromosome, although they can also be plasmid-encoded. A previous article in this journal provided a comprehensive review regarding efflux-mediated drug resistance in bacteria. In the past 5 years, significant progress has been achieved in further understanding of drug resistance-related efflux transporters and this review focuses on the latest studies in this field since 2003. This has been demonstrated in multiple aspects that include but are not limited to: further molecular and biochemical characterization of the known drug efflux pumps and identification of novel drug efflux pumps; structural elucidation of the transport mechanisms of drug transporters; regulatory mechanisms of drug efflux pumps; determining the role of the drug efflux pumps in other functions such as stress responses, virulence and cell communication; and development of efflux pump inhibitors. Overall, the multifaceted implications of drug efflux transporters warrant novel strategies to combat multidrug resistance in bacteria.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario K1A OK9, Canada
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202, USA
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26
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Distribution Pattern and Physical Mapping of CCC Plasmid-Mediated Multidrug-Resistance in some G-ve Bacteria Recovered from Hospitals and Haemodialysis Units Wastewater at Al-Madinah Al-Munawarah. J Taibah Univ Med Sci 2009. [DOI: 10.1016/s1658-3612(09)70084-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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27
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Abstract
A model is a representation of some real phenomena and contains aspects or elements of the real system to be modeled. The model reflects (or duplicates) the type of behavior (or mechanisms) seen in the real system. The main characteristic of any model is the mapping of elements or parameters found in the system being studied (e.g. tongue dorsum biofilm in situ) on to the model being devised (e.g. laboratory perfusion biofilm). Such parameters include correct physico-chemical (abiotic) conditions as well as biotic conditions that occur in both model and reality. The main purpose of a model is to provide information that better explains the processes observed or thought to occur in the real system. Such models can be abstract (mental, conceptual, theoretical, mathematical or computational) or 'physical', e.g. in the form of a real disaggregated in vitro system or laboratory model. A wide range of different model systems have been used in oral biofilm research. These will be briefly reviewed with special emphasis on those models that have contributed most to knowledge in breath odor research. The different model systems used in breath odor research are compared. Finally, the requirements for developing an overall 'bad breath model' from considering the processes as a whole (real oral cavity, substrates in saliva, biotransformation by tongue microflora, odor gases in the breath) and extending this to the detection of malodor by the human nose will be outlined and discussed.
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Affiliation(s)
- J Greenman
- Faculty of Applied Sciences, University of the West of England (UWE), Bristol, UK.
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28
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Assessment of the possible effect of the four antimicrobial treatment substances on the emergence of antimicrobial resistance - Scientific Opinion of the Panel on Biological Hazards. EFSA J 2008. [DOI: 10.2903/j.efsa.2008.659] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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29
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Gilbert P, McBain A, Sreenivasan P. Common therapeutic approaches for the control of oral biofilms: microbiological safety and efficacy. Clin Microbiol Infect 2007; 13 Suppl 4:17-24. [PMID: 17716292 DOI: 10.1111/j.1469-0691.2007.01800.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Triclosan is widely employed in many consumer and healthcare products. The increasing employment of triclosan in a range of consumer products where there is no proven benefit for hygiene has been severely criticised. Laboratory studies demonstrate theoretical risks that the wide-scale use of triclosan might compromise its efficacy as well as the activity of third-party antibiotics. The precautionary principle would dictate against the use of triclosan, at least in those products where there was no demonstrable health benefit. The theoretical risks, however, are not supported by either field or clinical studies, or by laboratory studies using bacterial microcosms. Numerous clinical studies, as well as historical data, demonstrate the clinical benefits of hygiene adjuncts such as triclosan and triclosan/copolymer in oral care products where these compensate for deficiencies in mechanical hygiene (brushing and flossing). The balance of risk and benefit is firmly in favour of the continued use of dentifrices (toothpastes) and mouthwashes containing active agents such as triclosan.
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Affiliation(s)
- P Gilbert
- University of Manchester, Oxford Road, Manchester, UK.
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30
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Beauvais A, Schmidt C, Guadagnini S, Roux P, Perret E, Henry C, Paris S, Mallet A, Prévost MC, Latgé JP. An extracellular matrix glues together the aerial-grown hyphae of Aspergillus fumigatus. Cell Microbiol 2007; 9:1588-600. [PMID: 17371405 DOI: 10.1111/j.1462-5822.2007.00895.x] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pulmonary infections due to Aspergillus fumigatus result from the development of a colony of tightly associated hyphae in contact with the air, either in the alveoli (invasive aspergillosis) or in an existing cavity (aspergilloma). The fungal ball observed in vivo resembles an aerial colony obtained in agar medium in vitro more than a mycelial mass obtained in liquid shaken conditions that have been classically used to date to study A. fumigatus physiology. For this reason, we embarked on an analysis of the characteristics of A. fumigatus colonies grown in aerial static conditions. (i) Under static aerial conditions, mycelial growth is greater than in shaken, submerged conditions. (ii) The colony surface of A. fumigatus revealed the presence of an extracellular hydrophobic matrix that acts as a cohesive linkage bonding hyphae into a contiguous sheath. (iii) The extracellular matrix is composed of galactomannan, alpha1,3 glucans, monosaccharides and polyols, melanin and proteins including major antigens and hydrophobins. (iv) A. fumigatus colonies were more resistant to polyenes than shake, submerged mycelium. This is the first analysis of the three dimensional structure of a mycelial colony. Knowledge of this multicellular organization will impact our future understanding of the pathobiology of aerial mold pathogens.
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Tabak M, Scher K, Hartog E, Romling U, Matthews KR, Chikindas ML, Yaron S. Effect of triclosan on Salmonella typhimurium at different growth stages and in biofilms. FEMS Microbiol Lett 2006; 267:200-6. [PMID: 17156099 DOI: 10.1111/j.1574-6968.2006.00547.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Triclosan is a potent biocide that is included in a diverse range of products. This research was aimed to investigate the susceptibility of planktonic and biofilm-associated Salmonella enterica serovar Typhimurium to triclosan, and to identify potential mechanisms of adaptation. The effect of triclosan was studied on planktonic Salmonella (log and stationary phases), on biofilm-associated cells, on bacteria derived from disrupted biofilms and on a biofilm-deficient mutant. An eight-log reduction of exponentially growing cells was observed with 1000 micro g mL(-1) triclosan within 10 min, a 3.6-log reduction in stationary cells and a 6.3-log reduction in stationary cells of a biofilm-deficient mutant (P<0.05). Biofilm-associated cells were tolerant (1-log reduction). However, biofilm-derived cells showed sensitivity to triclosan similar to stationary-phase cells. Triclosan induced the transcription of fabI and micF. Within biofilms, triclosan also up-regulated the transcription of acrAB, encoding for an efflux pump, marA, and the cellulose-synthesis-coding genes bcsA and bcsE. Thus, Salmonella within biofilms could experience reduced influx, increased efflux and enhanced exopolysaccharides production. Our results demonstrated that the tolerance of Salmonella towards triclosan in the biofilm was attributed to low diffusion through the extracellular matrix, while changes of gene expression might provide further resistance to triclosan and to other antimicrobials.
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Affiliation(s)
- Mina Tabak
- Department of Biotechnology and Food Engineering, Technion, Haifa, Israel
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Herzberg M, Kaye IK, Peti W, Wood TK. YdgG (TqsA) controls biofilm formation in Escherichia coli K-12 through autoinducer 2 transport. J Bacteriol 2006; 188:587-98. [PMID: 16385049 PMCID: PMC1347309 DOI: 10.1128/jb.188.2.587-598.2006] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
YdgG is an uncharacterized protein that is induced in Escherichia coli biofilms. Here it is shown that deletion of ydgG decreased extracellular and increased intracellular concentrations of autoinducer 2 (AI-2); hence, YdgG enhances transport of AI-2. Consistent with this hypothesis, deletion of ydgG resulted in a 7,000-fold increase in biofilm thickness and 574-fold increase in biomass in flow cells. Also consistent with the hypothesis, deletion of ydgG increased cell motility by increasing transcription of flagellar genes (genes induced by AI-2). By expressing ydgG in trans, the wild-type phenotypes for extracellular AI-2 activity, motility, and biofilm formation were restored. YdgG is also predicted to be a membrane-spanning protein that is conserved in many bacteria, and it influences resistance to several antimicrobials, including crystal violet and streptomycin (this phenotype could also be complemented). Deletion of ydgG also caused 31% of the bacterial chromosome to be differentially expressed in biofilms, as expected, since AI-2 controls hundreds of genes. YdgG was found to negatively modulate expression of flagellum- and motility-related genes, as well as other known products essential for biofilm formation, including operons for type 1 fimbriae, autotransporter protein Ag43, curli production, colanic acid production, and production of polysaccharide adhesin. Eighty genes not previously related to biofilm formation were also identified, including those that encode transport proteins (yihN and yihP), polysialic acid production (gutM and gutQ), CP4-57 prophage functions (yfjR and alpA), methionine biosynthesis (metR), biotin and thiamine biosynthesis (bioF and thiDFH), anaerobic metabolism (focB, hyfACDR, ttdA, and fumB), and proteins with unknown function (ybfG, yceO, yjhQ, and yjbE); 10 of these genes were verified through mutation to decrease biofilm formation by 40% or more (yfjR, bioF, yccW, yjbE, yceO, ttdA, fumB, yjiP, gutQ, and yihR). Hence, it appears YdgG controls the transport of the quorum-sensing signal AI-2, and so we suggest the gene name tqsA.
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Affiliation(s)
- Moshe Herzberg
- Department of Chemical Engineering and Biology, Texas A & M University, 220 Jack E. Brown Building, College Station, TX 77843-3122, USA
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Irie Y, O'toole GA, Yuk MH. Pseudomonas aeruginosa rhamnolipids disperse Bordetella bronchiseptica biofilms. FEMS Microbiol Lett 2006; 250:237-43. [PMID: 16098688 DOI: 10.1016/j.femsle.2005.07.012] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Revised: 07/11/2005] [Accepted: 07/12/2005] [Indexed: 11/30/2022] Open
Abstract
We have previously reported that the respiratory pathogen Bordetella bronchiseptica can form biofilms in vitro. In this report, we demonstrate the disruption of B. bronchiseptica biofilms by rhamnolipids secreted from Pseudomonas aeruginosa. This suggests that biosurfactants such as rhamnolipids may be utilized as antimicrobial agents for removing Bordetella biofilms.
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Affiliation(s)
- Yasuhiko Irie
- Department of Microbiology, University of Pennsylvania School of Medicine, 201C Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104-6084, USA
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Abstract
AIMS To investigate biofilm production and esp carriage in enterococci. METHODS Biofilm production in vancomycin resistant enterococci (VRE) and vancomycin susceptible enterococci (VSE) was tested on a microtitre plate method, using both brain heart infusion (BHI) broth and human serum as media. Isolates were screened for the esp gene, which has been reported to be essential for biofilm formation in enterococci, by means of the polymerase chain reaction. RESULTS None of seven VRE and nine of 28 VSE tested formed a biofilm. One initially negative VRE Enterococcus faecium isolate produced a strong biofilm after 21 weeks of dry starvation on a cotton swab. By Fisher's exact test, there was no significant difference in biofilm formation between VRE and VSE, E faecalis and E faecium, or isolates from different sites. Biofilm formation was independent of possession of the esp gene. One isolate produced a strong biofilm in human serum but only a weak biofilm in BHI, whereas another produced a moderate biofilm in human serum but a weak biofilm in BHI. CONCLUSIONS The acquisition of vancomycin resistance may result in a lower ability to form biofilms, but a larger study using clinical isolates is needed to test this hypothesis. That one initially negative VRE isolate produced a strong biofilm after prolonged dry starvation suggests that biofilm formation may be an adaptive response. The esp gene does not appear to be necessary or sufficient for production of biofilms in enterococci.
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Affiliation(s)
- A A Ramadhan
- School of Biomedical Sciences, Faculty of Health, Sciences, Cumberland Campus, PO Box 170, Lidcombe, NSW 1825, Australia.
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Marques CNH, Salisbury VC, Greenman J, Bowker KE, Nelson SM. Discrepancy between viable counts and light output as viability measurements, following ciprofloxacin challenge of self-bioluminescent Pseudomonas aeruginosa biofilms. J Antimicrob Chemother 2005; 56:665-71. [PMID: 16105852 DOI: 10.1093/jac/dki285] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES To utilize bioluminescence to follow the effect of ciprofloxacin challenge on Pseudomonas aeruginosa biofilms. METHODS The Sorbarod continuous perfusion culture system was used for the cultivation of biofilms of a self-bioluminescent strain of P. aeruginosa PAO1. Biofilms were challenged with ciprofloxacin (5 mg/L) in the perfusing medium for 3 h and allowed to recover to pre-challenge population levels before initiation of a second 3 h challenge. In addition to determining eluate and biofilm cell survival by conventional viable plate counts, light output was monitored via a luminometer and a low-light-level ICCD camera, to give an indication of metabolism. The effect of drug challenge on biofilm structure was investigated using an environmental scanning electron microscope, which allowed discernment of changes to the three-dimensional biofilm architecture. RESULTS On challenge with ciprofloxacin, eluate light output measurements declined to a lesser extent than viable counts for the same samples and also indicated that post-challenge recovery of the biofilm metabolism did not occur as rapidly as suggested by viable count data. Photon detection by ICCD camera allowed real-time, non-invasive imaging of metabolic activity within intact biofilms. CONCLUSIONS The application of a bioluminescent reporter strain to biofilm research provides valuable real-time positional data on the efficacy of anti-biofilm treatment strategies.
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Affiliation(s)
- Cláudia N H Marques
- Centre for Research in Biomedicine, Faculty of Applied Sciences, University of the West of England, Bristol, Coldharbour Lane, Bristol BS16 1QY, UK
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Rickard AH, Lindsay S, Lockwood GB, Gilbert P. Induction of the mar operon by miscellaneous groceries. J Appl Microbiol 2005; 97:1063-8. [PMID: 15479423 DOI: 10.1111/j.1365-2672.2004.02401.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To investigate the potential of non-antibacterial consumer products to act as inducers of the multiple antibiotic resistance (mar) operon of Escherichia coli SPC105. METHODS AND RESULTS Wells were cut into chemically defined agar medium (CDM) contained within Petri dishes. Molten agar slurries were prepared by mixing known quantities of 35 consumer products with molten CDM and these were pipetted into each well. Plates were overlaid with molten CDM (5 ml), containing 40 microg ml(-1) X-gal and approx. 1000 CFU ml(-1) of an overnight culture of E. coli SPC105 containing a chromosomal marOII::lacZ fusion. After incubation (37 degrees C, 24 h), plates were examined for zones of growth inhibition and the presence of a blue coloration, indicative of mar (marOII::lacZ) induction. Of the 35 products tested (nine herbs and spices, 19 food and drinks and seven household products), 24 (69%) of the items produced inhibitory zones and 22 (63%) of the items induced mar expression. Apple puree was inhibitory but did not induce marOII::lacZ. Mustard, chilli and garlic were shown to be powerful inducers of marOII::lacZ. Overall six products were shown to be powerful marOII::lacZ inducers. None of these made hygiene claims. CONCLUSIONS In addition to induction by specific biocides and antibiotics, mar is induced by the exposure of bacteria to natural substances, many of which are common to a domiciliary setting. SIGNIFICANCE AND IMPACT OF THE STUDY Concern that the overuse of antibacterials within consumer products might select for mar-mediated resistance is shortsighted and fails to recognize the ubiquity of inducers in our environment.
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Affiliation(s)
- A H Rickard
- School of Pharmacy, University of Manchester, UK
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Al-Bakri AG, Gilbert P, Allison DG. Immigration and emigration of Burkholderia cepacia and Pseudomonas aeruginosa between and within mixed biofilm communities. J Appl Microbiol 2004; 96:455-63. [PMID: 14962125 DOI: 10.1111/j.1365-2672.2004.02201.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To investigate the dynamics of binary culture biofilm formation through use of both the Sorbarod model of biofilm growth and the constant depth film fermenter (CDFF). METHODS AND RESULTS Pseudo steady-state biofilm cultures of laboratory and clinical strains of Pseudomonas aeruginosa, selected on the basis of their ability to produce a Burkholderia cepacia growth-inhibitory substance, were established on Sorbarod filters and challenged with corresponding planktonic grown cultures of B. cepacia. Reverse challenges were also conducted. Both B. cepacia and P. aeruginosa were able to form steady-state monoculture biofilms after 48 h growth. When steady-state biofilms of B. cepacia NTCT 10661 were challenged with planktonically grown P. aeruginosa PAO1 known to produce a B. cepacia growth-inhibitory substance, the immigrant population was rapidly and almost completely bound to the biofilm, displacing B. cepacia. By contrast, established biofilms of P. aeruginosa PAO1 resisted immigration of B. cepacia 10661. Similar experiments conducted with a nongrowth inhibitory substance producing clinical pairing of P. aeruginosa 313113 and B. cepacia 313113 led to the formation of stable, mixed biofilm populations in both instances. Moreover, co-inoculation with these clinical isolates resulted in a stable, mixed steady-state biofilm. Similar observations were made for biofilms generated in CDFFs. In such instances following pan-swapping between two monoculture CDFFs, B. cepacia 313113 was able to integrate into an established P. aeruginosa 313113 biofilm to form a stable binary biofilm. CONCLUSIONS Establishment of a mixed species community follows a specific sequence of inoculation that may either be due to some degree of match between co-colonizers or that P. aeruginosa predisposes uncolonized sections of the surface to permit B. cepacia colonization. SIGNIFICANCE AND IMPACT OF THE STUDY Colonization of a surface with one bacterial species confers colonization resistance towards other species. Disinfection of a surface might well increase the probability of pathogen harbourage.
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Affiliation(s)
- A G Al-Bakri
- School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester, England, UK
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Sufya N, Allison DG, Gilbert P. Clonal variation in maximum specific growth rate and susceptibility towards antimicrobials. J Appl Microbiol 2004; 95:1261-7. [PMID: 14633000 DOI: 10.1046/j.1365-2672.2003.02079.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To examine associations between growth rate within bacterial populations and survival patterns following treatment with antimicrobial agents. METHODS AND RESULTS Time survival data were generated for the inactivation of Escherichia coli populations, grown as batch and continuous cultures, exposed to ciprofloxacin, benzalkonium chloride and tetracycline. Time-survivor plots were biphasic. Surviving cells were collected and immediately re-exposed to agent or were regrown and then re-exposed. Survivors were resistant to immediate challenge with any of the treatment agents. This resistance was lost on regrowth suggesting that survival reflects an expressed phenotype within a subset of the culture (persisters) rather than individual resistant clones or nonspecific quenching of the test agent. The fraction of persisters increased with decreasing growth rate when cultures were prepared in continuous culture. CONCLUSIONS Clonal growth rates within populations were determined by culture of individual cells within microtitre plate wells. The fraction of clones, in batch cultures, growing maximally at rates below the apparent threshold for susceptibility to the test agents was sufficient to explain the results of continuous culture experiments. SIGNIFICANCE AND IMPACT OF THE STUDY The presence of persisters in populations of bacteria relate to small subset of cells that are growing only slowly or are metabolically quiescent.
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Affiliation(s)
- N Sufya
- School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester, UK
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Russell AD. Biocide use and antibiotic resistance: the relevance of laboratory findings to clinical and environmental situations. THE LANCET. INFECTIOUS DISEASES 2003; 3:794-803. [PMID: 14652205 DOI: 10.1016/s1473-3099(03)00833-8] [Citation(s) in RCA: 274] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Antibiotics are used as chemotherapeutic drugs, and biocides are used as antiseptics, disinfectants, and preservatives. Several factors affect biocidal activity, notably concentration, period of contact, pH, temperature, the presence of interfering material, and the types, numbers, location, and condition of microorganisms. Bacterial cells as part of natural or artificial (laboratory) biofilm communities are much less susceptible than planktonic cells to antibiotics and biocides. Assessment of biocidal activity by bactericidal testing is more relevant than by determination of minimum inhibitory concentrations. Biocides and antibiotics may show some similarities in their mechanisms of action and common mechanisms of bacterial insusceptibility may apply, but there are also major differences. In the laboratory, bacteria can become less susceptible to some biocides. Decreased resistance may be stable or unstable and may be accompanied by a low-level increase in antibiotic resistance. Laboratory studies are useful for examining stress responses and basic mechanisms of action and of bacterial insusceptibility to antibacterial agents. Translation of such findings to the clinical and environmental situations to provide evidence of a possible relation between biocide use and clinical antibiotic resistance is difficult and should be viewed with caution.
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Affiliation(s)
- A D Russell
- Welsh School of Pharmacy, Cardiff University, Cardiff, UK.
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Batté M, Mathieu L, Laurent P, Prévost M. Influence of phosphate and disinfection on the composition of biofilms produced from drinking water, as measured by fluorescence in situ hybridization. Can J Microbiol 2003; 49:741-53. [PMID: 15162199 DOI: 10.1139/w03-094] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Biofilms were grown in annular reactors supplied with drinking water enriched with 235 µg C/L. Changes in the biofilms with ageing, disinfection, and phosphate treatment were monitored using fluorescence in situ hybridization. EUB338, BET42a, GAM42a, and ALF1b probes were used to target most bacteria and the alpha (α), beta (β), and gamma (γ) subclasses of Proteobacteria, respectively. The stability of biofilm composition was checked after the onset of colonization between T = 42 days and T = 113 days. From 56.0% to 75.9% of the cells detected through total direct counts with DAPI (4'-6-diamidino-2-phenylindole) were also detected with the EUB338 probe, which targets the 16S rRNA of most bacteria. Among these cells, 16.9%–24.7% were targeted with the BET42a probe, 1.8%–18.3% with the ALF1b probe, and <2.5% with the GAM42a probe. Phosphate treatment induced a significant enhancement to the proportion of γ-Proteobacteria (detected with the GAM42a probe), a group that contains many health-related bacteria. Disinfection with monochloramine for 1 month or chlorine for 3 days induced a reduction in the percentage of DAPI-stained cells that hybridized with the EUB338 probe (as expressed by percentages of EUB338 counts/DAPI) and with any of the ALF1b, BET42a, and GAM42a probes. The percentage of cells detected by any of the three probes (ALF1b+BET42a+GAM42a) tended to decrease, and reached in total less than 30% of the EUB338-hybridized cells. Disinfection with chlorine for 7 days induced a reverse shift; an increase in the percentage of EUB338 counts targeted by any of these three probes was noted, which reached up to 87%. However, it should be noted that the global bacterial densities (heterotrophic plate counts and total direct counts) tended to decrease over the duration of the experiment. Therefore, those bacteria that could be considered to resist 7 days of chlorination constituted a small part of the initial biofilm community, up to the point at which the other bacterial groups were destroyed by chlorination. The results suggest that there were variations in the kinetics of inactivation by disinfectant, depending on the bacterial populations involved.Key words: biofilm, phosphate, chlorine, monochloramine, FISH, drinking water.
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Affiliation(s)
- M Batté
- Ecole Polytechnique de Montréal, C.P. 6079, Succ. Centre Ville, Montréal, QC H3C 3A7, Canada
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Schwartz T, Hoffmann S, Obst U. Formation of natural biofilms during chlorine dioxide and u.v. disinfection in a public drinking water distribution system. J Appl Microbiol 2003; 95:591-601. [PMID: 12911708 DOI: 10.1046/j.1365-2672.2003.02019.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS The influence of two disinfection techniques on natural biofilm development during drinking water treatment and subsequent distribution is compared with regard to the supply of a high-quality drinking water. METHODS AND RESULTS The growth of biofilms was studied using the biofilm device technique in a real public technical drinking water asset. Different pipe materials which are commonly used in drinking water facilities (hardened polyethylene, polyvinyl chloride, steel and copper) were used as substrates for biofilm formation. Apart from young biofilms, several months old biofilms were compared in terms of material dependence, biomass and physiological state. Vital staining of biofilms with 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and the DNA-specific 4',6-diamidino-2-phenylindole (DAPI) staining resulted in a significant difference in physiological behaviour of biofilm populations depending on the disinfection technique. Compared with chlorine dioxide disinfection (0.12-0.16 mg l-1), the respiratory activities of the micro-organisms were increased on all materials during u.v. disinfection (u.v.254; 400 J m-2). The biofilm biocoenosis was analysed by in situ hybridization with labelled oligonucleotides specific for some subclasses of Proteobacteria. Using PCR and additional hybridization techniques, the biofilms were also tested for the presence of Legionella spp., atypical mycobacteria and enterococci. The results of the molecular-biological experiments in combination with cultivation tests showed that enterococci were able to pass the u.v. disinfection barrier and persist in biofilms of the distribution system, but not after chlorine dioxide disinfection. CONCLUSIONS The results indicated that bacteria are able to regenerate and proliferate more effectively after u.v. irradiation at the waterworks, and chlorine dioxide disinfection appears to be more applicative to maintain a biological stable drinking water. SIGNIFICANCE AND IMPACT OF THE STUDY As far as the application of u.v. disinfection is used for conditioning of critical water sources for drinking water, the efficiency of u.v. irradiation in natural systems should reach a high standard to avoid adverse impacts on human health.
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Affiliation(s)
- T Schwartz
- Department of Environmental Microbiology, Water Technology and Geotechnology Division, Institute for Technical Chemistry, Forschungszentrum Karlsruhe GmbH, Karlsruhe, Germany.
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Mukherjee PK, Chandra J, Kuhn DM, Ghannoum MA. Mechanism of fluconazole resistance in Candida albicans biofilms: phase-specific role of efflux pumps and membrane sterols. Infect Immun 2003; 71:4333-40. [PMID: 12874310 PMCID: PMC165995 DOI: 10.1128/iai.71.8.4333-4340.2003] [Citation(s) in RCA: 400] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida albicans biofilms are formed through three distinct developmental phases and are associated with high fluconazole (FLU) resistance. In the present study, we used a set of isogenic Candida strains lacking one or more of the drug efflux pumps Cdr1p, Cdr2p, and Mdr1p to determine their role in FLU resistance of biofilms. Additionally, variation in sterol profile as a possible mechanism of drug resistance was investigated. Our results indicate that parent and mutant strains formed similar biofilms. However, biofilms formed by double and triple mutants were more susceptible to FLU at 6 h (MIC = 64 and 16 microg/ml, respectively) than the wild-type strain (MIC > 256 microg/ml). At later time points (12 and 48 h), all the strains became resistant to this azole (MIC > or = 256 microg/ml), indicating lack of involvement of efflux pumps in resistance at late stages of biofilm formation. Northern blot analyses revealed that Candida biofilms expressed CDR and MDR1 genes in all the developmental phases, while planktonic cells expressed these genes only at the 12- and 48-h time points. Functionality of efflux pumps was assayed by rhodamine (Rh123) efflux assays, which revealed significant differences in Rh123 retention between biofilm and planktonic cells at the early phase (P = 0.0006) but not at later stages (12 and 48 h). Sterol analyses showed that ergosterol levels were significantly decreased (P < 0.001) at intermediate and mature phases, compared to those in early-phase biofilms. These studies suggest that multicomponent, phase-specific mechanisms are operative in antifungal resistance of fungal biofilms.
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Affiliation(s)
- Pranab K Mukherjee
- Center for Medical Mycology, Department of Dermatology, University Hospitals of Cleveland and Case Western Reserve University, Ohio 44106, USA
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Truong-Bolduc QC, Zhang X, Hooper DC. Characterization of NorR protein, a multifunctional regulator of norA expression in Staphylococcus aureus. J Bacteriol 2003; 185:3127-38. [PMID: 12730173 PMCID: PMC154082 DOI: 10.1128/jb.185.10.3127-3138.2003] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We characterized a Staphylococcus aureus norA gene expression regulator, NorR, initially identified from its binding to the norA promoter. The norR gene was 444 bp in length, located approximately 7 kb upstream from the norA gene, and encoded a predicted 17.6-kDa protein. Overexpression of norR in wild-type S. aureus strain ISP794 led to a fourfold decrease in sensitivity to quinolones and ethidium bromide and an increase in the level of norA transcripts, suggesting that NorR acts as a positive regulator of norA expression. Overexpression of norR in sarA and agr mutants did not alter quinolone sensitivity or levels of norA transcription, indicating that the presence of these two global regulatory systems is necessary for NorR to affect the expression of norA. Insertion and disruption of norR in ISP794 increased resistance to quinolones by 4- to 16-fold but had no effect on norA transcription, suggesting that NorR acts as a repressor for another unidentified efflux pump or pumps. These mutants also exhibited an exaggerated clumping phenotype in liquid media, which was complemented fully by a plasmid-encoded norR gene. Collectively, these results indicate that NorR is a multifunctional regulator, affecting cell surface properties as well as the expression of NorA and likely other multidrug resistance efflux pumps.
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Affiliation(s)
- Que Chi Truong-Bolduc
- Division of Infectious Diseases and Medical Services, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114-2696, USA
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Gilbert P, McBain AJ. Literature-based evaluation of the potential risks associated with impregnation of medical devices and implants with triclosan. Surg Infect (Larchmt) 2003; 3 Suppl 1:S55-63. [PMID: 12573040 DOI: 10.1089/sur.2002.3.s1-55] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND This report is a review of the published literature for studies of triclosan that address mechanism of action, efficacy on skin and in the oral cavity, and the potential for development of resistance. METHODS Triclosan citations from the past three decades were searched using Medline and other search engines. The techniques used in these studies included in vitro antimicrobial sensitivity, molecular genetics, and enzyme and membrane biochemistry. Oral cavity efficacy and resistance studies were conducted in human volunteers in trials lasting up to 7 months. Efficacy on skin was reported in clinical trials lasting up to 12 months. RESULTS The minimal inhibitory concentration of triclosan against Staphylococcus aureus and Escherichia coli is reported to be 0.1 and 5.0 microg/mL, respectively. Triclosan acts by blocking enoyl acyl carrier protein reductase, an enzyme essential for fatty acid biosynthesis. Its biocidal activity involves a plethora of nonspecific perturbations of cellular structural elements, including the cell membrane. In the oral cavity, triclosan use was associated with significant reductions in recoverable flora; there was no evidence of resistance or emergence of opportunistic pathogens. On skin, in a neonatal intensive care unit, triclosan use was associated with a significant reduction in methicillin-resistant S. aureus (MRSA) infections, a diminished need for antibiotics, and a decreased incidence of nosocomial infections. CONCLUSION There is currently no evidence that long-term application of triclosan products to the skin or oral cavity selects for triclosan-resistant populations. Given the short-term nature of suture use, it is highly unlikely that such use would do other than reduce the risks of postoperative infection.
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Affiliation(s)
- Peter Gilbert
- School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester, United Kingdom.
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Gilbert P, McBain AJ. Potential impact of increased use of biocides in consumer products on prevalence of antibiotic resistance. Clin Microbiol Rev 2003; 16:189-208. [PMID: 12692093 PMCID: PMC153147 DOI: 10.1128/cmr.16.2.189-208.2003] [Citation(s) in RCA: 189] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There has recently been much controversy surrounding the increased use of antibacterial substances in a wide range of consumer products and the possibility that, as with antibiotics, indiscriminate use of biocides might contribute to the overall pattern of susceptibility in the general environment and in the clinic. Such speculation, based on the isolation of resistant mutants from in vitro monoculture experiments, is not reflected by an emergence of biocide-resistant strains in vivo. This review provides a broad coverage of the biocide and resistance literature and evaluates the potential risks, perceived from such laboratory monoculture experiments, against evidence gathered over 50 years of field studies. An explanation for the continued effectiveness of broad-spectrum biocidal agents against the decline in efficacy of therapeutic agents is provided based on the fitness costs of resistance and the ubiquity of naturally occurring substances that possess antibacterial effect. While we conclude from this review of the literature that the incorporation of antibacterial agents into a widening sphere of personal products has had little or no impact on the patterns of microbial susceptibility observed in the environment, the associated risks remain finite. The use of such products should therefore be associated with a clear demonstration of added value either to consumer health or to the product life. Hygienic products should therefore be targeted to applications for which the risks have been established.
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Affiliation(s)
- Peter Gilbert
- School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester M13 9PL, United Kingdom.
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Gilbert P, McBain AJ. Literature-Based Evaluation of the Potential Risks Associated with Impregnation of Medical Devices and Implants with Triclosan. Surg Infect (Larchmt) 2002. [DOI: 10.1089/10962960260496343] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Abstract
Bacteria that attach to a surface and grow as a biofilm are protected from killing by antibiotics. Reduced antibiotic susceptibility contributes to the persistence of biofilm infections such as those associated with implanted devices. The protective mechanisms at work in biofilms appear to be distinct from those that are responsible for conventional antibiotic resistance. In biofilms, poor antibiotic penetration, nutrient limitation and slow growth, adaptive stress responses, and formation of persister cells are hypothesized to constitute a multi-layered defense. The genetic and biochemical details of these biofilm defenses are only now beginning to emerge. Each gene and gene product contributing to this resistance may be a target for the development of new chemotherapeutic agents. Disabling biofilm resistance may enhance the ability of existing antibiotics to clear infections involving biofilms that are refractory to current treatments.
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Affiliation(s)
- Philip S Stewart
- Center for Biofilm Engineering, Department of Chemical Engineering, Montana State University, Bozeman, Montana 59717-3980, USA.
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Gilbert P, Allison D, McBain A. Biofilms in vitro
and in vivo
: do singular mechanisms imply cross-resistance? J Appl Microbiol 2002. [DOI: 10.1046/j.1365-2672.92.5s1.5.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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