351
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Lam AK, Hill MA, Moen EL, Pusavat J, Wouters CL, Rice CV. Cationic Branched Polyethylenimine (BPEI) Disables Antibiotic Resistance in Methicillin-Resistant Staphylococcus epidermidis (MRSE). ChemMedChem 2018; 13:2240-2248. [PMID: 30193012 PMCID: PMC6869378 DOI: 10.1002/cmdc.201800433] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/05/2018] [Indexed: 11/10/2022]
Abstract
Staphylococcus epidermidis is one of the most prevalent prokaryotic species on human skin and mucosal membranes that constitute the commensal flora. S. epidermidis has become one of the most common causes of primary bacteremia. Infections are difficult to diagnose because the pathogen has natural niches on human skin and the ability to adhere to inanimate surfaces via biofilms. Alarmingly, S. epidermidis has acquired resistance to many antibiotics, which presents a danger to human health. Known as methicillin-resistant S. epidermidis (MRSE), most clinical isolates of MRSE in North America exhibit β-lactam resistance primarily due to the presence of mecA, a gene that bestows β-lactam antibiotic resistance in a manner similar to methicillin-resistant Staphylococcus aureus (MRSA). MecA encodes for expression of penicillin-binding protein 2a (PBP2a), which is absent in β-lactam susceptible strains of S. epidermidis. We can disable this resistance factor in MRSE with 600-Da branched polyethylenimine (BPEI). Cationic BPEI targets anionic wall teichoic acid (WTA), an essential cofactor for proper functioning of PBP2a. We found that BPEI synergizes the activity of β-lactam antibiotics against MRSE. Growth curves suggest that the combination of BPEI and oxacillin is bactericidal. Electron micrographs indicate abnormalities in the cellular septa and cell walls of treated samples. Therefore, first-line clinical treatments can be effective against MRSE when used in combination with BPEI.
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Affiliation(s)
- Anh K Lam
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, 73019, USA
| | - Melissa A Hill
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, 73019, USA
| | - Erika L Moen
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, 73019, USA
| | - Jennifer Pusavat
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, 73019, USA
| | - Cassandra L Wouters
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, 73019, USA
| | - Charles V Rice
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, 73019, USA
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352
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Li H, Qin Y, Mao X, Zheng W, Luo G, Xu X, Zheng J. Silencing of cyt-c4 led to decrease of biofilm formation in Aeromonas hydrophila. Biosci Biotechnol Biochem 2018; 83:221-232. [PMID: 30304991 DOI: 10.1080/09168451.2018.1528543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Aquaculture suffers from a number of diseases caused by Aeromonas hydrophila. Biofilm can protect bacteria from antibiotic therapy. To identify the genes those play crucial roles in A. hydrophila biofilm formation, a library of mini-Tn10 transposon insertion mutants of A. hydrophila B11 has been constructed, and 10 mutants were subjected to biofilm formation assay. The biofilm formation ability of mutant (B188) was significantly decreased compared with B11. The DNA sequence flanking the mini-Tn10 transposon inserted showed that an ORF of approximately 576 bp of the mutant strain B188 was inserted. This ORF putatively displays the highest identity (92%) with the cytochrome c4 gene (cyt-c4) of A. hydrophila subsp. hydrophila ATCC 7966. Silencing cyt-c4 led to deficiencies in biofilm formation, adhesion, drug resistance and pathogenicity of A. hydrophila, which suggests that cyt-c4 plays crucial role in the biofilm formation and virulence mechanisms of A. hydrophila. ABBREVIATIONS: GEN: gentamycin; SDZ: sulfadiazine; AK: amikacin; P: penicillin; CFP: cefoperazone; LEV: levofloxacin; MH: minocycline; FFC: florfenicol; TE: tetracycline; AMP: ampicillin; KAN: kanamycin; STR: streptomycin; SXT: sulfamethoxazole/trimethoprim; DO: doxycycline; OT: Oxytetracycline.
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Affiliation(s)
- Huiyao Li
- a Fisheries College , Jimei University , Xiamen , Fujian Province , China.,b Engineering Research Center of the Modern Technology for Eel Industry , Ministry of Education , Xiamen , P.R. China.,c Fujian Provincial Key Laboratory of Marine Fishery Resources and Eco-environment , Xiamen , Fujian Province , China
| | - Yingxue Qin
- a Fisheries College , Jimei University , Xiamen , Fujian Province , China.,b Engineering Research Center of the Modern Technology for Eel Industry , Ministry of Education , Xiamen , P.R. China.,c Fujian Provincial Key Laboratory of Marine Fishery Resources and Eco-environment , Xiamen , Fujian Province , China
| | - Xiuxiu Mao
- a Fisheries College , Jimei University , Xiamen , Fujian Province , China.,b Engineering Research Center of the Modern Technology for Eel Industry , Ministry of Education , Xiamen , P.R. China.,c Fujian Provincial Key Laboratory of Marine Fishery Resources and Eco-environment , Xiamen , Fujian Province , China
| | - Wanmei Zheng
- d SiChuan Agricultural University , Ya'an , Sichuan Province , China
| | - Gang Luo
- a Fisheries College , Jimei University , Xiamen , Fujian Province , China.,b Engineering Research Center of the Modern Technology for Eel Industry , Ministry of Education , Xiamen , P.R. China.,c Fujian Provincial Key Laboratory of Marine Fishery Resources and Eco-environment , Xiamen , Fujian Province , China
| | - Xiaojin Xu
- a Fisheries College , Jimei University , Xiamen , Fujian Province , China.,b Engineering Research Center of the Modern Technology for Eel Industry , Ministry of Education , Xiamen , P.R. China.,c Fujian Provincial Key Laboratory of Marine Fishery Resources and Eco-environment , Xiamen , Fujian Province , China
| | - Jiang Zheng
- a Fisheries College , Jimei University , Xiamen , Fujian Province , China.,b Engineering Research Center of the Modern Technology for Eel Industry , Ministry of Education , Xiamen , P.R. China.,c Fujian Provincial Key Laboratory of Marine Fishery Resources and Eco-environment , Xiamen , Fujian Province , China
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353
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Kaplan JB, Mlynek KD, Hettiarachchi H, Alamneh YA, Biggemann L, Zurawski DV, Black CC, Bane CE, Kim RK, Granick MS. Extracellular polymeric substance (EPS)-degrading enzymes reduce staphylococcal surface attachment and biocide resistance on pig skin in vivo. PLoS One 2018; 13:e0205526. [PMID: 30304066 PMCID: PMC6179274 DOI: 10.1371/journal.pone.0205526] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/26/2018] [Indexed: 02/04/2023] Open
Abstract
Staphylococcal extracellular polymeric substances (EPS) such as extracellular DNA (eDNA) and poly-N-acetylglucosamine surface polysaccharide (PNAG) mediate numerous virulence traits including host colonization and antimicrobial resistance. Previous studies showed that EPS-degrading enzymes increase staphylococcal biocide susceptibility in vitro and in vivo, and decrease virulence in animal models. In the present study we tested the effect of EPS-degrading enzymes on staphylococcal skin colonization and povidone iodine susceptibility using a novel in vivo pig model that enabled us to colonize and treat 96 isolated areas of skin on a single animal in vivo. To quantitate skin colonization, punch biopsies of colonized areas were homogenized, diluted, and plated on agar for colony forming unit enumeration. Skin was colonized with either Staphylococcus epidermidis or Staphylococcus aureus. Two EPS-degrading enzymes, DNase I and the PNAG-degrading enzyme dispersin B, were employed. Enzymes were tested for their ability to inhibit skin colonization and detach preattached bacteria. The effect of enzymes on the susceptibility of preattached S. aureus to killing by povidone iodine was also measured. We found that dispersin B significantly inhibited skin colonization by S. epidermidis and detached preattached S. epidermidis cells from skin. A cocktail of dispersin B and DNase I detached preattached S. aureus cells from skin and increased their susceptibility to killing by povidone iodine. These findings suggest that staphylococcal EPS components such as eDNA and PNAG contribute to skin colonization and biocide resistance in vivo. EPS-degrading enzymes may be a useful adjunct to conventional skin antisepsis procedures in order to further reduce skin bioburden.
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Affiliation(s)
- Jeffrey B. Kaplan
- Department of Biology, American University, Washington, District of Columbia, United States of America
- * E-mail:
| | - Kevin D. Mlynek
- Department of Biology, American University, Washington, District of Columbia, United States of America
| | - Hashani Hettiarachchi
- Department of Biology, American University, Washington, District of Columbia, United States of America
| | - Yonas A. Alamneh
- Wound Infections Department, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Lionel Biggemann
- Wound Infections Department, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Daniel V. Zurawski
- Wound Infections Department, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Chad C. Black
- Wound Infections Department, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Charles E. Bane
- Wound Infections Department, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Robert K. Kim
- Wound Infections Department, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Mark S. Granick
- Department of Surgery, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America
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354
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Moulton‐Brown CE, Friman V. Rapid evolution of generalized resistance mechanisms can constrain the efficacy of phage-antibiotic treatments. Evol Appl 2018; 11:1630-1641. [PMID: 30344632 PMCID: PMC6183449 DOI: 10.1111/eva.12653] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 05/17/2018] [Accepted: 05/23/2018] [Indexed: 12/12/2022] Open
Abstract
Antimicrobial resistance has been estimated to be responsible for over 700,000 deaths per year; therefore, new antimicrobial therapies are urgently needed. One way to increase the efficiency of antibiotics is to use them in combination with bacteria-specific parasitic viruses, phages, which have been shown to exert additive or synergistic effects in controlling bacteria. However, it is still unclear to what extent these combinatory effects are limited by rapid evolution of resistance, especially when the pathogen grows as biofilm on surfaces typical for many persistent and chronic infections. To study this, we used a microcosm system, where genetically isogenic populations of Pseudomonas aeruginosa PAO1 bacterial pathogen were exposed to a phage 14/1, gentamycin or a combination of them both in a spatially structured environment. We found that even though antibiotic and phage-antibiotic treatments were equally effective at controlling bacteria in the beginning of the experiment, combination treatment rapidly lost its efficacy in both planktonic and biofilm populations. In a mechanistic manner, this was due to rapid resistance evolution: While both antibiotic and phage selected for increased resistance on their own, phage selection correlated positively with increase in antibiotic resistance, while biofilm growth, which provided generalized resistance mechanism, was favoured most in the combination treatment. Only relatively small cost of resistance and weak evidence for coevolutionary dynamics were observed. Together, these results suggest that spatial heterogeneity can promote rapid evolution of generalized resistance mechanisms without corresponding increase in phage infectivity, which could potentially limit the effectiveness of phage-antibiotic treatments in the evolutionary timescale.
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355
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Jarząb N, Walczak M, Smoliński D, Sionkowska A. The impact of medicinal brines on microbial biofilm formation on inhalation equipment surfaces. BIOFOULING 2018; 34:963-975. [PMID: 30614293 DOI: 10.1080/08927014.2018.1515353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 08/07/2018] [Accepted: 08/15/2018] [Indexed: 06/09/2023]
Abstract
Materials such as polyvinyl chloride, polypropylene, and polyethylene are used for the construction of medical equipment, including inhalation equipment. Inhalation equipment, because of the wet conditions and good oxygenation, constitutes a perfect environment for microbial biofilm formation. Biofilms may affect microbiological cleanliness of inhalation facilities and installations and promote the development of pathogenic bacteria. Microbial biofilms can form even in saline environments. Therefore, the aim of this study was to evaluate the effect of medicinal brines on microbial biofilm formation on the surfaces of inhalation equipment. The study confirmed the high risk of biofilm formation on surfaces used in inhalation equipment. Isolated microorganisms belonged to potential pathogens of the respiratory system, which can pose a health threat to hospital patients. The introduction of additional contaminants increased the amount of bacterial biofilm. On the other hand, the presence of brines significantly limited the amount of biofilm, thus eliminating the risk of infections.
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Affiliation(s)
- Natalia Jarząb
- a Department of Environmental Microbiology and Biotechnology, Faculty of Biology and Environmental Protection , Nicolaus Copernicus University , Toruń , Poland
| | - Maciej Walczak
- a Department of Environmental Microbiology and Biotechnology, Faculty of Biology and Environmental Protection , Nicolaus Copernicus University , Toruń , Poland
| | - Dariusz Smoliński
- b Department of Cell Biology, Faculty of Biology and Environmental Protection , Nicolaus Copernicus University , Toruń , Poland
| | - Alina Sionkowska
- c Department of Chemistry of Biomaterials and Cosmetics, Faculty of Chemistry , Nicolaus Copernicus University , Toruń , Poland
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356
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Bagchi D, Rathnam VSS, Lemmens P, Banerjee I, Pal SK. NIR-Light-Active ZnO-Based Nanohybrids for Bacterial Biofilm Treatment. ACS OMEGA 2018; 3:10877-10885. [PMID: 30320255 PMCID: PMC6173506 DOI: 10.1021/acsomega.8b00716] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 07/10/2018] [Indexed: 05/28/2023]
Abstract
Nanomaterials with antimicrobial properties triggered by external stimuli appear to be a promising and innovative substitute for the destruction of antibiotic-resistant superbugs as they can induce multiple disruptions in the cellular mechanism. This study demonstrates the use of squaraine (SQ) dye as the photosensitive material, activated in the near-infrared tissue-transparent therapeutic window. The dye has been covalently attached to the ZnO nanoparticle surface, forming ZnO-SQ nanohybrids. The formation of the nanohybrids is confirmed using Fourier transform infrared and other optical spectroscopic methods. The photoinduced interfacial electron transfer process (as confirmed using the time-resolved fluorescence technique) from the excited state of SQ to the conduction band of ZnO is responsible for the greater reactive oxygen species (ROS) generation ability of the nanohybrid. The production of photoactivated ROS (especially singlet oxygen species) by ZnO-SQ provides remarkable antimicrobial action against clinically significant Staphylococcus aureus. Detailed investigations suggest synergistic involvement of cell membrane disruption and nanoparticle internalization followed by photoinduced intracellular ROS generation, which result in an unprecedented 95% bacterial killing activity by the nanohybrid. Moreover, the efficacy of the nanohybrid for disruption of bacterial biofilms has been examined. The electron microscopic images suggest significant bacterial cell death following structural alteration and reduced adherence property of the biofilms. Nanodimension-driven greater internalization of ZnO-SQ followed by an improved dissolution of ZnO in an acidic environment of the biofilm as well as red-light-driven interfacial charge separation and ROS generation improves the efficacy of the material for biofilm destruction. An artificial medical implant mimicking titanium sheets coated with ZnO-SQ depicts light-triggered disruption in the adherence property of matured biofilms. The cytotoxicity and hemolysis assays show inherent biocompatibility of the photoactive nanohybrid. This study is notably promising for the treatment of life-threatening drug-resistant infections and eradication of biofilms formed within artificial implants.
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Affiliation(s)
- Damayanti Bagchi
- Department
of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
| | - V. S. Sharan Rathnam
- Department
of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Peter Lemmens
- Institute
for Condensed Matter Physics and Laboratory for Emerging Nanometrology, TU Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany
| | - Indranil Banerjee
- Department
of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Samir Kumar Pal
- Department
of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
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357
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Association of Antibiotic Resistance, Cell Adherence, and Biofilm Production with the Endemicity of Nosocomial Klebsiella pneumoniae. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7012958. [PMID: 30345305 PMCID: PMC6174813 DOI: 10.1155/2018/7012958] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/31/2018] [Indexed: 11/17/2022]
Abstract
Klebsiella pneumoniae is a leading cause of multiple nosocomial infections, some of which are associated with high mortality. The increasing prevalence of antibiotic-resistant strains highlights their clinical importance and how complicated managing treatment can be. In this study, we investigated antimicrobial resistance, cell adherence, and biofilm production of nosocomial K. pneumoniae strains isolated from surveillance studies in a Mexican tertiary hospital and evaluated the potential association of these phenotypes with endemicity. The great majority of the clones exhibited adhesion to cultured epithelial cells and were strong biofilm producers. A direct relationship between adhesion phenotypes, biofilm production, and endemicity was not always apparent. Biofilm formation and production of ESBL did not appear to be directly associated. Notably, all the endemic strains were multidrug-resistant. This study emphasizes that while endemic strains possess various virulence-associated properties, antimicrobial resistance appears to be a determining factor of their endemicity.
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358
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Wi YM, Patel R. Understanding Biofilms and Novel Approaches to the Diagnosis, Prevention, and Treatment of Medical Device-Associated Infections. Infect Dis Clin North Am 2018; 32:915-929. [PMID: 30241715 DOI: 10.1016/j.idc.2018.06.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Treatment of medical device-related infections is challenging and recurrence is common. The main reason for this is that microorganisms adhere to the surfaces of medical devices and enter into a biofilm state in which they display distinct growth rates, structural features, and protection from antimicrobial agents and host immune mechanisms compared with their planktonic counterparts. This article reviews how microorganisms form biofilms and the mechanisms of protection against antimicrobial agents and the host immune system provided by biofilms. Also discussed are innovative strategies for the diagnosis of biofilm-associated infection and novel approaches to treatment and prevention of medical device-associated infections.
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Affiliation(s)
- Yu Mi Wi
- Division of Infectious Diseases, Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University, 158 palyong-ro, MasanHoiwon-gu, Changwon-si, Gyeongsangnam-do 51353, Korea
| | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA; Division of Infectious Diseases, Department of Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA.
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359
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van Harten RM, van Woudenbergh E, van Dijk A, Haagsman HP. Cathelicidins: Immunomodulatory Antimicrobials. Vaccines (Basel) 2018; 6:vaccines6030063. [PMID: 30223448 PMCID: PMC6161271 DOI: 10.3390/vaccines6030063] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/30/2018] [Accepted: 09/12/2018] [Indexed: 12/20/2022] Open
Abstract
Cathelicidins are host defense peptides with antimicrobial and immunomodulatory functions. These effector molecules of the innate immune system of many vertebrates are diverse in their amino acid sequence but share physicochemical characteristics like positive charge and amphipathicity. Besides being antimicrobial, cathelicidins have a wide variety in immunomodulatory functions, both boosting and inhibiting inflammation, directing chemotaxis, and effecting cell differentiation, primarily towards type 1 immune responses. In this review, we will examine the biology and various functions of cathelicidins, focusing on putting in vitro results in the context of in vivo situations. The pro-inflammatory and anti-inflammatory functions are highlighted, as well both direct and indirect effects on chemotaxis and cell differentiation. Additionally, we will discuss the potential and limitations of using cathelicidins as immunomodulatory or antimicrobial drugs.
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Affiliation(s)
- Roel M van Harten
- Division Molecular Host Defence, Dept. Infectious diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
| | - Esther van Woudenbergh
- Division Molecular Host Defence, Dept. Infectious diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
| | - Albert van Dijk
- Division Molecular Host Defence, Dept. Infectious diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
| | - Henk P Haagsman
- Division Molecular Host Defence, Dept. Infectious diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
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360
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Kamaruzzaman NF, Tan LP, Mat Yazid KA, Saeed SI, Hamdan RH, Choong SS, Wong WK, Chivu A, Gibson AJ. Targeting the Bacterial Protective Armour; Challenges and Novel Strategies in the Treatment of Microbial Biofilm. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E1705. [PMID: 30217006 PMCID: PMC6164881 DOI: 10.3390/ma11091705] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/07/2018] [Accepted: 09/09/2018] [Indexed: 02/07/2023]
Abstract
Infectious disease caused by pathogenic bacteria continues to be the primary challenge to humanity. Antimicrobial resistance and microbial biofilm formation in part, lead to treatment failures. The formation of biofilms by nosocomial pathogens such as Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Klebsiella pneumoniae (K. pneumoniae) on medical devices and on the surfaces of infected sites bring additional hurdles to existing therapies. In this review, we discuss the challenges encountered by conventional treatment strategies in the clinic. We also provide updates on current on-going research related to the development of novel anti-biofilm technologies. We intend for this review to provide understanding to readers on the current problem in health-care settings and propose new ideas for new intervention strategies to reduce the burden related to microbial infections.
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Affiliation(s)
- Nor Fadhilah Kamaruzzaman
- Faculty of Veterinary Medicine, Universiti Malaysia Kelantan, Pengkalan Chepa 16100, Kelantan, Malaysia.
| | - Li Peng Tan
- Faculty of Veterinary Medicine, Universiti Malaysia Kelantan, Pengkalan Chepa 16100, Kelantan, Malaysia.
| | - Khairun Anisa Mat Yazid
- Faculty of Veterinary Medicine, Universiti Malaysia Kelantan, Pengkalan Chepa 16100, Kelantan, Malaysia.
| | - Shamsaldeen Ibrahim Saeed
- Faculty of Veterinary Medicine, Universiti Malaysia Kelantan, Pengkalan Chepa 16100, Kelantan, Malaysia.
| | - Ruhil Hayati Hamdan
- Faculty of Veterinary Medicine, Universiti Malaysia Kelantan, Pengkalan Chepa 16100, Kelantan, Malaysia.
| | - Siew Shean Choong
- Faculty of Veterinary Medicine, Universiti Malaysia Kelantan, Pengkalan Chepa 16100, Kelantan, Malaysia.
| | - Weng Kin Wong
- School of Health Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia.
| | - Alexandru Chivu
- UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery & Interventional Science, University College London, London NW3 2PF, UK.
| | - Amanda Jane Gibson
- Royal Veterinary College, Pathobiology and Population Sciences, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK.
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361
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Control of Biofilm Formation in Healthcare: Recent Advances Exploiting Quorum-Sensing Interference Strategies and Multidrug Efflux Pump Inhibitors. MATERIALS 2018; 11:ma11091676. [PMID: 30201944 PMCID: PMC6163278 DOI: 10.3390/ma11091676] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/18/2018] [Accepted: 09/07/2018] [Indexed: 12/28/2022]
Abstract
Biofilm formation in healthcare is an issue of considerable concern, as it results in increased morbidity and mortality, imposing a significant financial burden on the healthcare system. Biofilms are highly resistant to conventional antimicrobial therapies and lead to persistent infections. Hence, there is a high demand for novel strategies other than conventional antibiotic therapies to control biofilm-based infections. There are two approaches which have been employed so far to control biofilm formation in healthcare settings: one is the development of biofilm inhibitors based on the understanding of the molecular mechanism of biofilm formation, and the other is to modify the biomaterials which are used in medical devices to prevent biofilm formation. This review will focus on the recent advances in anti-biofilm approaches by interrupting the quorum-sensing cellular communication system and the multidrug efflux pumps which play an important role in biofilm formation. Research efforts directed towards these promising strategies could eventually lead to the development of better anti-biofilm therapies than the conventional treatments.
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362
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Barbera L, De Plano LM, Franco D, Gattuso G, Guglielmino SPP, Lando G, Notti A, Parisi MF, Pisagatti I. Antiadhesive and antibacterial properties of pillar[5]arene-based multilayers. Chem Commun (Camb) 2018; 54:10203-10206. [PMID: 30137099 DOI: 10.1039/c8cc05659e] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A new type of coating, based on carboxylato-pillar[5]arene/poly(allylamine hydrochloride) multilayer films, for the sustained release of antibiotics with in vitro antiadhesive and antimicrobial activity against Gram-positive and Gram-negative bacteria is described.
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Affiliation(s)
- Lucia Barbera
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy.
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363
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Guan A, Wang Y, Phillips KS. An extraction free modified o-phthalaldehyde assay for quantifying residual protein and microbial biofilms on surfaces. BIOFOULING 2018; 34:925-934. [PMID: 30362370 DOI: 10.1080/08927014.2018.1521959] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 08/27/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
Biological contamination of surfaces in industry and healthcare is an important vector of disease transmission. Current assays for detecting surface-adherent contamination require extraction of biological soil. However, physical inaccessibility or poor solubility may limit recovery. Here, how the o-phthalaldehyde (OPA) protein assay can be modified to measure residual protein (modeled with bovine serum albumin) or biofilm on a surface without extraction is described. The assay limit of detection (LOD) for protein was 1.6 µg cm-2. The detection threshold for Staphylococcus epidermis biofilm was 117 µg cm-2. The clinical utility of the method was demonstrated for measurements taken from clinically used endoscopes. Since this method is more sensitive than extraction-based testing, clinical results should not be compared with conventional benchmarks. By enabling direct detection and quantification of soils in complex or hard-to-reach areas, this method has potential to improve the margin of safety in medical and industrial cleaning processes.
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Affiliation(s)
- Allan Guan
- a Division of Biology, Chemistry and Materials Science, Center for Devices and Radiological Health , Office of Science and Engineering Laboratories, Office of Medical Products and Tobacco, United States Food and Drug Administration , Silver Spring , MD , USA
| | - Yi Wang
- a Division of Biology, Chemistry and Materials Science, Center for Devices and Radiological Health , Office of Science and Engineering Laboratories, Office of Medical Products and Tobacco, United States Food and Drug Administration , Silver Spring , MD , USA
| | - K Scott Phillips
- a Division of Biology, Chemistry and Materials Science, Center for Devices and Radiological Health , Office of Science and Engineering Laboratories, Office of Medical Products and Tobacco, United States Food and Drug Administration , Silver Spring , MD , USA
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364
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Dhand C, Balakrishnan Y, Ong ST, Dwivedi N, Venugopal JR, Harini S, Leung CM, Low KZW, Loh XJ, Beuerman RW, Ramakrishna S, Verma NK, Lakshminarayanan R. Antimicrobial quaternary ammonium organosilane cross-linked nanofibrous collagen scaffolds for tissue engineering. Int J Nanomedicine 2018; 13:4473-4492. [PMID: 30122921 PMCID: PMC6080871 DOI: 10.2147/ijn.s159770] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Introduction In search for cross-linkers with multifunctional characteristics, the present work investigated the utility of quaternary ammonium organosilane (QOS) as a potential cross-linker for electrospun collagen nanofibers. We hypothesized that the quaternary ammonium ions improve the electrospinnability by reducing the surface tension and confer antimicrobial properties, while the formation of siloxane after alkaline hydrolysis could cross-link collagen and stimulate cell proliferation. Materials and methods QOS collagen nanofibers were electrospun by incorporating various concentrations of QOS (0.1%–10% w/w) and were cross-linked in situ after exposure to ammonium carbonate. The QOS cross-linked scaffolds were characterized and their biological properties were evaluated in terms of their biocompatibility, cellular adhesion and metabolic activity for primary human dermal fibroblasts and human fetal osteoblasts. Results and discussion The study revealed that 1) QOS cross-linking increased the flexibility of otherwise rigid collagen nanofibers and improved the thermal stability; 2) QOS cross-linked mats displayed potent antibacterial activity and 3) the biocompatibility of the composite mats depended on the amount of QOS present in dope solution – at low QOS concentrations (0.1% w/w), the mats promoted mammalian cell proliferation and growth, whereas at higher QOS concentrations, cytotoxic effect was observed. Conclusion This study demonstrates that QOS cross-linked mats possess anti-infective properties and confer niches for cellular growth and proliferation, thus offering a useful approach, which is important for hard and soft tissue engineering and regenerative medicine.
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Affiliation(s)
- Chetna Dhand
- Anti-Infectives Research Group, Singapore Eye Research Institute, The Academia, Discovery Tower, Singapore, , .,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore,
| | | | - Seow Theng Ong
- Dermatology and Skin Biology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore,
| | - Neeraj Dwivedi
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore
| | - Jayarama R Venugopal
- Faculty of Industrial Sciences & Technology, Universiti Malaysia Pahang, Gambang, Malaysia
| | - Sriram Harini
- Anti-Infectives Research Group, Singapore Eye Research Institute, The Academia, Discovery Tower, Singapore, ,
| | - Chak Ming Leung
- Department of Bioengineering, National University of Singapore, Singapore
| | - Kenny Zhi Wei Low
- Department of Mechanical Engineering, Faculty of Engineering, Center for Nanofibers and Nanotechnology, National University of Singapore, Singapore
| | - Xian Jun Loh
- Department of Mechanical Engineering, Faculty of Engineering, Center for Nanofibers and Nanotechnology, National University of Singapore, Singapore
| | - Roger W Beuerman
- Anti-Infectives Research Group, Singapore Eye Research Institute, The Academia, Discovery Tower, Singapore, , .,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore,
| | - Seeram Ramakrishna
- Soft Materials Department, Institute of Materials Research and Engineering, ASTAR (Agency for Science, Technology and Research, Singapore
| | - Navin Kumar Verma
- Anti-Infectives Research Group, Singapore Eye Research Institute, The Academia, Discovery Tower, Singapore, , .,Dermatology and Skin Biology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore,
| | - Rajamani Lakshminarayanan
- Anti-Infectives Research Group, Singapore Eye Research Institute, The Academia, Discovery Tower, Singapore, , .,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore,
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365
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Rzhepishevska O, Limanska N, Galkin M, Lacoma A, Lundquist M, Sokol D, Hakobyan S, Sjöstedt A, Prat C, Ramstedt M. Characterization of clinically relevant model bacterial strains of Pseudomonas aeruginosa for anti-biofilm testing of materials. Acta Biomater 2018; 76:99-107. [PMID: 29902594 DOI: 10.1016/j.actbio.2018.06.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/25/2018] [Accepted: 06/08/2018] [Indexed: 11/15/2022]
Abstract
There is a great interest in developing novel anti-biofilm materials in order to decrease medical device-associated bacterial infections causing morbidity and high healthcare costs. However, the testing of novel materials is often done using bacterial lab strains that may not exhibit the same phenotype as clinically relevant strains infecting medical devices. Furthermore, no consensus of strain selection exists in the field, making results very difficult to compare between studies. In this work, 19 clinical isolates of Pseudomonas aeruginosa originating from intubated patients in an intensive care unit have been characterized and compared to the lab reference strain PAO1 and a rmlC lipopolysaccharide mutant of PAO1. The adhesion and biofilm formation was monitored, as well as cell properties such as hydrophobicity, zeta potential and motility. Two groups of isolates were observed: one with high adhesion to polymer surfaces and one with low adhesion (the latter including PAO1). Furthermore, detailed biofilm assays in a flow system were performed using five characteristic isolates from the two groups. Confocal microscopy showed that the adhesion and biofilm formation of four of these five strains could be reduced dramatically on zwitterionic surface coatings. However, one isolate with pronounced swarming colonized and formed biofilm also on the antifouling surface. We demonstrate that the biofilm properties of clinical isolates can differ greatly from that of a standard lab strain and propose two clinical model strains for testing of materials designed for prevention of biofilm formation in the respiratory tract. The methodology used could beneficially be applied for screening of other collections of pathogens to identify suitable model strains for in vitro biofilm testing. STATEMENT OF SIGNIFICANCE Medical-device associated infections present a great challenge in health care. Therefore, much research is undertaken to prevent bacterial colonization of new types of biomaterials. The work described here characterizes, tests and presents a number of clinically relevant bacterial model strains for assessing biofilm formation by Pseudomonas aeruginosa. Such model strains are of importance as they may provide better predictability of lab testing protocols with respect to how well materials would perform in an infection situation in a patient. Furthermore, this study uses the strains to test the performance of polymer surfaces designed to repel bacterial adhesion and it is shown that the biofilm formation for four out of the five tested bacterial strains was reduced.
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Affiliation(s)
| | - Nataliia Limanska
- Department of Microbiology, Virology and Biotechnology, Odessa National University, Shampanskiy Lane 2, Odessa 65058, Ukraine.
| | - Mykola Galkin
- Department of Microbiology, Virology and Biotechnology, Odessa National University, Shampanskiy Lane 2, Odessa 65058, Ukraine.
| | - Alicia Lacoma
- Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Institut de Recerca Germans Trias i Pujol, Universitat Autònoma de Barcelona, CIBER Enfermedades Respiratorias, Spain.
| | | | - Dmytro Sokol
- Department of Microbiology, Virology and Biotechnology, Odessa National University, Shampanskiy Lane 2, Odessa 65058, Ukraine
| | - Shoghik Hakobyan
- Department of Chemistry, Umeå University, 90187 Umeå, Sweden; Queen Mary University of London, Mile End Road, London E1 4NS, UK.
| | - Anders Sjöstedt
- Department of Clinical Microbiology, Umeå University, SE-90 185 Umeå, Sweden.
| | - Cristina Prat
- Servei de Microbiologia, Hospital Universitari Germans Trias i Pujol, Institut de Recerca Germans Trias i Pujol, Universitat Autònoma de Barcelona, CIBER Enfermedades Respiratorias, Spain.
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366
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Pal S, Qureshi A, Purohit HJ. Intercepting signalling mechanism to control environmental biofouling. 3 Biotech 2018; 8:364. [PMID: 30105189 DOI: 10.1007/s13205-018-1383-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 07/29/2018] [Indexed: 12/29/2022] Open
Abstract
Biofouling in environmental systems employs bacterial quorum sensing signals (autoinducers) and extracellular polymeric substances to onset the event. The present review has highlighted on the fundamental mechanisms behind biofilm formation over broad spectrum environmental niches especially membrane biofouling in water systems and consequent chances of pathogenic contamination leading to global economic loss. It has broadly discussed on bioelectrical signal (via, potassium gradient) and molecular signal (via, AHLs) mediated quorum sensing which help to propagate biofilm formation. The review has illustrated the potential of genomic intervention towards biofouled membrane microbial community and has uncovered possible features of biofilm microenvironment like quorum quenching bacteria, bioelectrical waves capture, siderophores arrest and surface modifications. Based on information, the concept of interception of quorum signals (AHLs) and bioelectrical signals (K+) by employing electro-modified (negative charges) membrane surface have been hypothesized in the present review to favour anti-biofouling.
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Affiliation(s)
- Smita Pal
- 1Academy of Scientific and Innovative Research (AcSIR), CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, Maharashtra 440020 India
- 2CSIR-Environmental Biotechnology and Genomics Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, Maharashtra 440020 India
| | - Asifa Qureshi
- 1Academy of Scientific and Innovative Research (AcSIR), CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, Maharashtra 440020 India
- 2CSIR-Environmental Biotechnology and Genomics Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, Maharashtra 440020 India
| | - Hemant J Purohit
- 2CSIR-Environmental Biotechnology and Genomics Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, Maharashtra 440020 India
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367
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Rahimi R, Shams Es‐haghi S, Chittiboyina S, Mutlu Z, Lelièvre SA, Cakmak M, Ziaie B. Laser-Enabled Processing of Stretchable Electronics on a Hydrolytically Degradable Hydrogel. Adv Healthc Mater 2018; 7:e1800231. [PMID: 29947042 DOI: 10.1002/adhm.201800231] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 05/14/2018] [Indexed: 12/14/2022]
Abstract
Degradable electronics represent a rapidly emerging field of science and technology with the potential to serve short-term medical implantation applications where the device disappears once its function is complete. Despite many efforts in developing new types of degradable electronics, many of such systems are nonelastic and incompatible with the dynamic motion of native soft/elastic biological tissues. Herein, a photo-crosslinkable hydrogel with integrated electronics that are highly stretchable and degradable in liquid environments is demonstrated. The fabrication process takes advantage of facile laser micromachining of conductive patterns directly onto the hydrogel under ambient conditions and permanent hydrogel-hydrogel bonding. The robustness and degradation rate of hydrogel and the laser-processed encapsulated stretchable circuits is systematically investigated in different solutions under various conditions. Biocompatibility tests with non-neoplastic cells (HMT 3522 S1) and cancer cells (T4-2 and MDA-MB-231) are performed in 2D and 3D cell culture systems to confirm instead of evaluate the safety of the hydrogel and its byproducts during degradation as well as the zinc metal used in this technology. As a proof of concept, a stretchable hydrogel-based device that can be used for remote/wireless delivery of thermal energy into the tissue in contact with the hydrogel is fabricated.
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Affiliation(s)
- Rahim Rahimi
- Birck Nanotechnology Center Purdue University West Lafayette IN 47907‐2057 USA
- School of Electrical and Computer Engineering Purdue University West Lafayette IN 47907‐2035 USA
| | - Siamak Shams Es‐haghi
- Birck Nanotechnology Center Purdue University West Lafayette IN 47907‐2057 USA
- School of Materials Engineering Purdue University West Lafayette IN 47907‐2045 USA
| | - Shirisha Chittiboyina
- Department of Basic Medical Sciences Purdue University 625 Harrison Street West Lafayette IN 47907 USA
| | - Zeynep Mutlu
- Birck Nanotechnology Center Purdue University West Lafayette IN 47907‐2057 USA
- School of Materials Engineering Purdue University West Lafayette IN 47907‐2045 USA
| | - Sophie A. Lelièvre
- Department of Basic Medical Sciences Purdue University 625 Harrison Street West Lafayette IN 47907 USA
| | - Mukerrem Cakmak
- Birck Nanotechnology Center Purdue University West Lafayette IN 47907‐2057 USA
- School of Materials Engineering Purdue University West Lafayette IN 47907‐2045 USA
| | - Babak Ziaie
- Birck Nanotechnology Center Purdue University West Lafayette IN 47907‐2057 USA
- School of Electrical and Computer Engineering Purdue University West Lafayette IN 47907‐2035 USA
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368
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The Usefulness of Non-Toxic Plant Metabolites in the Control of Bacterial Proliferation. Probiotics Antimicrob Proteins 2018; 9:323-333. [PMID: 28357646 DOI: 10.1007/s12602-017-9259-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The effect of generally recognised as safe (GRAS) plant metabolites in regulating the growth of human pathogenic and probiotic bacteria and in the formation of biofilm was investigated. Thymol, carvacrol and eugenol showed the strongest antibacterial action against both pathogenic and probiotic microorganisms, at a subinhibitory concentration (SIC) of ≤50 μg ml-1. Genistein, hydroquinone, p-hydroxybenzoic acid and resveratrol also showed antibacterial effects but at a wide concentration range (SIC = 50-1000 μg ml-1). Catechin, gallic acid, protocatechuic acid and cranberry extracts were the most biologically compatible molecules (SIC ≥ 1000 μg ml-1). Regarding the effect on biofilm, it was observed that thymol, carvacrol and eugenol showed antibiofilm activity against all potential pathogenic bacteria tested whilst specifically enhancing probiotic aggregation. Catechin, genistein and cranberry extracts did not inhibit the pathogenic aggregation but they stimulated probiotic biofilm formation, whilst gallic acid, protocateuchic acid, hydroquinone, p-hydroxybenzoic acid and resveratrol did not show opposite effect on biofilm formation between pathogenic and probiotic microorganisms. These results indicate that an appropriate combination of GRAS plant metabolites, which have traditionally been used as dietary constituents due to their health-promoting characteristics, can also be extremely useful in the regulation of bacterial proliferation in the intestinal microbiota. Hence, it is suggested to apply these natural GRAS molecules as dietary supplements in the food industry in order to promote probiotic viability and to prevent or reduce colonisation or proliferation of intestinal pathogens.
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369
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Rezaie P, Pourhajibagher M, Chiniforush N, Hosseini N, Bahador A. The Effect of Quorum-Sensing and Efflux Pumps Interactions in Pseudomonas aeruginosa Against Photooxidative Stress. J Lasers Med Sci 2018; 9:161-167. [PMID: 30809326 DOI: 10.15171/jlms.2018.30] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Resistant infections essentially cause mortality in a burn unit. Several bacteria contribute to burn infections; among these, Pseudomonas aeruginosa majorly contributes to these infections revealing significant drug resistance. Similar to other bacteria, P. aeruginosa reveals various mechanisms to attain highest pathogenicity and resistance; among these, efflux pumps and quorum sensing are crucial. Quorum sensing enables effective communication between bacteria and synchronizes their gene expression resulting in optimum effect of the secreted proteins; alternatively, efflux pumps increase the bacterial resistance by pumping out the antimicrobial factors as well as the QS signals and precursors. Of recent, increasing episodes of drug resistance led to new findings and approaches for killing pathogenic bacteria without inducing the drug-resistant species. Photodynamic therapy (PDT), considered as an adjuvant and innovative method for conventional antibiotic therapy, is a photochemical reaction that includes visible light, oxygen, and a photosensitizer (PS). In this therapy, after exposure to visible light, the PS generates reactive oxygen species (ROS) that are bacteriostatic or bactericidal. Furthermore, this oxidative stress can disrupt the coordination of gene expression and alter the bacterial behavior. Considering the fact that the adaption and several gene expression patterns of microorganisms within the biofilm make them notably resistant to the recent antimicrobial treatments, this study aimed to emphasize the relationship between the efflux pump and QS under oxidative stress and their role in P. aeruginosa's reaction to PDT.
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Affiliation(s)
- Parizad Rezaie
- Department of Microbiology, Faculty of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Maryam Pourhajibagher
- Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Nasim Chiniforush
- Laser Research Center of Dentistry (LRCD), Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Nava Hosseini
- Department of Microbiology, Faculty of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Abbas Bahador
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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370
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Campana R, Biondo F, Mastrotto F, Baffone W, Casettari L. Chitosans as new tools against biofilms formation on the surface of silicone urinary catheters. Int J Biol Macromol 2018; 118:2193-2200. [PMID: 30012489 DOI: 10.1016/j.ijbiomac.2018.07.088] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/28/2018] [Accepted: 07/12/2018] [Indexed: 12/25/2022]
Abstract
Urinary catheters contamination by microorganisms is a major cause of hospital acquired infections and represents a limitation for long-term use. In this work, biofilms of Klebsiella pneumoniae and Escherichia coli clinical isolates were developed on urinary catheters for 48 and 72 h in artificial urine medium (AUM) with different molecular weight chitosans (AUM-CS solutions) at pH 5.0. The number of viable bacteria was determined by standard plate count agar while crystal violet (CV) staining was carried out to assess biomass production (optical density at 570 nm) in the mentioned conditions. Re-growth of each strain was also evaluated after 24 h re-incubation of the treated catheters. Significant decreases of log CFU/catheter and biomass production were observed for all the biofilms developed in AUM-CS compared with the controls in AUM. The percentages of biofilm removal were slightly higher for E. coli biofilms (up to 90.4%) than those of K. pneumoniae (89.7%); in most cases, the complete inhibition of bacterial re-growth on treated catheter pieces was observed. Contact time influenced chitosan efficacy rather than its molecular weight or the biofilms age. The results confirmed the potentiality of chitosans as a biomacromolecule tool to contrast biofilm formation and reduce bacterial re-growth on urinary catheters.
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Affiliation(s)
- Raffaella Campana
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, PU, Italy.
| | - Francesca Biondo
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, PU, Italy
| | - Francesca Mastrotto
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, PD, Italy
| | - Wally Baffone
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, PU, Italy
| | - Luca Casettari
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, PU, Italy
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371
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Cattò C, Villa F, Cappitelli F. Recent progress in bio-inspired biofilm-resistant polymeric surfaces. Crit Rev Microbiol 2018; 44:633-652. [DOI: 10.1080/1040841x.2018.1489369] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Cristina Cattò
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, Milano, Italy
| | - Federica Villa
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, Milano, Italy
| | - Francesca Cappitelli
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, Milano, Italy
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372
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Balasubramanian S, Skaf J, Holzgrabe U, Bharti R, Förstner KU, Ziebuhr W, Humeida UH, Abdelmohsen UR, Oelschlaeger TA. A New Bioactive Compound From the Marine Sponge-Derived Streptomyces sp. SBT348 Inhibits Staphylococcal Growth and Biofilm Formation. Front Microbiol 2018; 9:1473. [PMID: 30050506 PMCID: PMC6050364 DOI: 10.3389/fmicb.2018.01473] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/13/2018] [Indexed: 01/09/2023] Open
Abstract
Staphylococcus epidermidis, the common inhabitant of human skin and mucosal surfaces has emerged as an important pathogen in patients carrying surgical implants and medical devices. Entering the body via surgical sites and colonizing the medical devices through formation of multi-layered biofilms leads to refractory and persistent device-related infections (DRIs). Staphylococci organized in biofilms are more tolerant to antibiotics and immune responses, and thus are difficult-to-treat. The consequent morbidity and mortality, and economic losses in health care systems has strongly necessitated the need for development of new anti-bacterial and anti-biofilm-based therapeutics. In this study, we describe the biological activity of a marine sponge-derived Streptomyces sp. SBT348 extract in restraining staphylococcal growth and biofilm formation on polystyrene, glass, medically relevant titan metal, and silicone surfaces. A bioassay-guided fractionation was performed to isolate the active compound (SKC3) from the crude SBT348 extract. Our results demonstrated that SKC3 effectively inhibits the growth (MIC: 31.25 μg/ml) and biofilm formation (sub-MIC range: 1.95–<31.25 μg/ml) of S. epidermidis RP62A in vitro. Chemical characterization of SKC3 by heat and enzyme treatments, and mass spectrometry (HRMS) revealed its heat-stable and non-proteinaceous nature, and high molecular weight (1258.3 Da). Cytotoxicity profiling of SKC3 in vitro on mouse fibroblast (NIH/3T3) and macrophage (J774.1) cell lines, and in vivo on the greater wax moth larvae Galleria mellonella revealed its non-toxic nature at the effective dose. Transcriptome analysis of SKC3 treated S. epidermidis RP62A has further unmasked its negative effect on central metabolism such as carbon flux as well as, amino acid, lipid, and energy metabolism. Taken together, these findings suggest a potential of SKC3 as a putative drug to prevent staphylococcal DRIs.
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Affiliation(s)
| | - Joseph Skaf
- Institute of Pharmacy and Food Chemistry, University of Würzburg, Würzburg, Germany
| | - Ulrike Holzgrabe
- Institute of Pharmacy and Food Chemistry, University of Würzburg, Würzburg, Germany
| | - Richa Bharti
- Core Unit Systems Medicine, University of Würzburg, Würzburg, Germany
| | - Konrad U Förstner
- Core Unit Systems Medicine, University of Würzburg, Würzburg, Germany
| | - Wilma Ziebuhr
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Ute H Humeida
- GEOMAR Helmholtz Centre for Ocean Research, RD3 Marine Microbiology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Usama R Abdelmohsen
- Department of Pharmacognosy, Faculty of Pharmacy, Minia University, Minia, Egypt
| | - Tobias A Oelschlaeger
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
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373
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In Vitro Activity of Bacteriophages Against Planktonic and Biofilm Populations Assessed by Flow Cytometry. Methods Mol Biol 2018. [PMID: 29119430 DOI: 10.1007/978-1-4939-7395-8_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
The in vitro activity of bacteriophages against planktonic cultures and biofilms is commonly evaluated by culture methods. However, these methods can lead to an underestimation of total bacterial cells when they undergo different physiological states.This chapter describes the methodology used to assess the in vitro activity of bacteriophages against planktonic cultures of bacteria in different metabolic states and biofilm populations by flow cytometry.
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374
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Magana M, Sereti C, Ioannidis A, Mitchell CA, Ball AR, Magiorkinis E, Chatzipanagiotou S, Hamblin MR, Hadjifrangiskou M, Tegos GP. Options and Limitations in Clinical Investigation of Bacterial Biofilms. Clin Microbiol Rev 2018; 31:e00084-16. [PMID: 29618576 PMCID: PMC6056845 DOI: 10.1128/cmr.00084-16] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.
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Affiliation(s)
- Maria Magana
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
| | - Christina Sereti
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Microbiology, Thriassio General Hospital, Attiki, Greece
| | - Anastasios Ioannidis
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece
| | - Courtney A Mitchell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Anthony R Ball
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| | - Emmanouil Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens, Athens-Goudi, Greece
| | | | - Michael R Hamblin
- Harvard-MIT Division of Health Science and Technology, Cambridge, Massachusetts, USA
- Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George P Tegos
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
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375
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Wu S, Altenried S, Zogg A, Zuber F, Maniura-Weber K, Ren Q. Role of the Surface Nanoscale Roughness of Stainless Steel on Bacterial Adhesion and Microcolony Formation. ACS OMEGA 2018; 3:6456-6464. [PMID: 30023948 PMCID: PMC6045408 DOI: 10.1021/acsomega.8b00769] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 05/28/2018] [Indexed: 05/25/2023]
Abstract
Hospital-acquired infections can cause serious complications and are a severe problem because of the increased emergence of antibiotic-resistant bacteria. Biophysical modification of the material surfaces to prevent or reduce bacteria adhesion is an attractive alternative to antibiotic treatment. Since stainless steel is a widely used material for implants and in hospital settings, in this work, we used stainless steel to investigate the effect of the material surface topographies on bacterial adhesion and early biofilm formation. Stainless steel samples with different surface roughnesses Rq in a range of 217.9-56.6 nm (Ra in a range of 172.5-45.2 nm) were fabricated via electropolishing and compared for adhesion of bacterial pathogens Pseudomonas aeruginosa and Staphylococcus aureus. It was found that the number of viable cells on the untreated rough surface was at least 10-fold lower than those on the electropolished surfaces after 4 h of incubation time for P. aeruginosa and 15-fold lower for S. aureus. Fluorescence images and scanning electron microscopy images revealed that the bacterial cells tend to adhere individually as single cells on untreated rough surfaces. In contrast, clusters of the bacterial cells (microcolonies) were observed on electropolished smooth surfaces. Our study demonstrates that nanoscale surface roughness can play an important role in restraining bacterial adhesion and formation of microcolonies.
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Affiliation(s)
- Songmei Wu
- School
of Science, Beijing Jiaotong University, No. 3 Shangyuancun, Haidian District, Beijing 100044, P. R. China
| | - Stefanie Altenried
- Laboratory
for Biointerfaces, Empa, Swiss Federal Laboratories
for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Andi Zogg
- HESS
Medizintechnik AG, Grabenstrasse
14, 8865 Bilten, Switzerland
| | - Flavia Zuber
- Laboratory
for Biointerfaces, Empa, Swiss Federal Laboratories
for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Katharina Maniura-Weber
- Laboratory
for Biointerfaces, Empa, Swiss Federal Laboratories
for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Qun Ren
- Laboratory
for Biointerfaces, Empa, Swiss Federal Laboratories
for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
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Rubini D, Banu SF, Nisha P, Murugan R, Thamotharan S, Percino MJ, Subramani P, Nithyanand P. Essential oils from unexplored aromatic plants quench biofilm formation and virulence of Methicillin resistant Staphylococcus aureus. Microb Pathog 2018; 122:162-173. [PMID: 29920307 DOI: 10.1016/j.micpath.2018.06.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 06/15/2018] [Accepted: 06/15/2018] [Indexed: 12/31/2022]
Abstract
In the current study we have evaluated the antibiofilm and antivirulent properties of unexplored essential oils (EOs) obtained from Pogostemon heyneanus and Cinnamomum tamala against Methicillin Resistant Staphylococcus aureus (MRSA) strains. The EOs from both the aromatic plants was screened for their ability to prevent biofilm formation and to disrupt preformed biofilms. The efficacy of both the EOs to disrupt the preformed biofilms of various MRSA strains was determined by Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM).The EOs were further able to reduce the Extracellular polymeric substance (EPS) and slime synthesis the two factors of the biofilm assemblage. The EOs was also found to be effective in reducing virulence factors like staphyloxanthin and hemolysin. In silico docking studies were performed for the major components of essential oils and dehydroxysqualene synthase of MRSA which is responsible for the synthesis of staphyloxanthin. The results suggest that (E)-nerolidol showed better binding affinity towards the enzyme. Other compounds have similar binding strengths with the enzyme. Furthermore, the synergistic effect EOs along with the commercially available DNaseI and Marine Bacterial DNase (MBD) showed that the synergistic effect had enhanced biofilm disruption ability. The results show that EOs from P. heyneanus and C. tamala has potential antivirulent and biofilm inhibitory properties against clinical and drug resistant S. aureus strains. The present study highlights the importance of bioprospecting plant based natural products as an alternative for antibiotics owing to the emergence of multi-drug resistant strains.
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Affiliation(s)
- Durairajan Rubini
- Biofilm Biology Laboratory, Anusandhan Kendra II, School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur 613 401, Tamil Nadu, India
| | - Sanaulla Farisa Banu
- Biofilm Biology Laboratory, Anusandhan Kendra II, School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur 613 401, Tamil Nadu, India
| | - Prakash Nisha
- Biofilm Biology Laboratory, Anusandhan Kendra II, School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur 613 401, Tamil Nadu, India
| | - Ramar Murugan
- School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur 613 401, Tamil Nadu, India
| | - Subbiah Thamotharan
- Biomolecular Crystallography Laboratory, Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur 613 401, Tamil Nadu, India
| | - María Judith Percino
- Laboratorio de Polímeros, Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Complejo de Ciencias, ICUAP, Edif. 103H, 22 Sur y San Claudio, Puebla, Puebla, C.P. 72570, Mexico
| | - Prabha Subramani
- Biofilm Biology Laboratory, Anusandhan Kendra II, School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur 613 401, Tamil Nadu, India
| | - Paramasivam Nithyanand
- Biofilm Biology Laboratory, Anusandhan Kendra II, School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur 613 401, Tamil Nadu, India; Centre for Research on Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur 613 401, Tamil Nadu, India.
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377
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Rubini D, Farisa Banu S, Veda Hari BN, Ramya Devi D, Gowrishankar S, Karutha Pandian S, Nithyanand P. Chitosan extracted from marine biowaste mitigates staphyloxanthin production and biofilms of Methicillin- resistant Staphylococcus aureus. Food Chem Toxicol 2018; 118:733-744. [PMID: 29908268 DOI: 10.1016/j.fct.2018.06.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/09/2018] [Accepted: 06/11/2018] [Indexed: 01/24/2023]
Abstract
Multidrug-resistant (MDR) Staphylococcus aureus is a major cause of biofilm-associated and indwelling device related infections. The present study explores the anti-virulent and antibiofilm potency of chitosan extracted from the shells of the marine crab Portunus sanguinolentus against Methicillin Resistant Staphylococcus aureus (MRSA). The chemical characterization results revealed that the extracted chitosan (EC) has structural analogy to that of a commercial chitosan (CC). The extracted chitosan was found to be effective in reducing the staphyloxanthin pigment, a characteristic virulence feature of MRSA that promotes resistance to reactive oxygen species. Furthermore, Confocal laser scanning microscope (CLSM) revealed that EC exhibited a phenomenal dose dependent antibiofilm efficacy against mature biofilms of the standard as well as clinical MRSA strains and Scanning Electron Microscopy (SEM) confirmed EC had a higher efficacy in disrupting the thick Exopolysaccharide (EPS) layer than CC. Additionally, EC and CC did not have any cytotoxic effects when tested on lung epithelial cell lines. Thus, the study exemplifies the anti-virulent properties of a marine bioresource which is till date discarded as a biowaste.
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Affiliation(s)
- Durairajan Rubini
- Biofilm Biology Laboratory, Centre for Research on Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613 401, Tamil Nadu, India
| | - Sanaulla Farisa Banu
- Biofilm Biology Laboratory, Centre for Research on Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613 401, Tamil Nadu, India
| | - B Narayanan Veda Hari
- School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613 401, Tamil Nadu, India.
| | - Durai Ramya Devi
- School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613 401, Tamil Nadu, India
| | - Shanmugaraj Gowrishankar
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, 630 004, Tamil Nadu, India
| | | | - Paramasivam Nithyanand
- Biofilm Biology Laboratory, Centre for Research on Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613 401, Tamil Nadu, India.
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378
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Effect of Polyvalence on the Antibacterial Activity of a Synthetic Peptide Derived from Bovine Lactoferricin against Healthcare-Associated Infectious Pathogens. BIOMED RESEARCH INTERNATIONAL 2018; 2018:5252891. [PMID: 29984236 PMCID: PMC6015718 DOI: 10.1155/2018/5252891] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/07/2018] [Accepted: 04/11/2018] [Indexed: 11/29/2022]
Abstract
Antimicrobial peptides (AMPs) are gaining interest as potential therapeutic agents. Peptides derived from bovine lactoferricin B (LfcinB) have been reported to exhibit antimicrobial activity, and the LfcinB RRWQWR sequence is the smallest known motif that exhibits antibacterial and cytotoxic activity. Our goal was to examine the effect of multicopy arrangements of the RRWQWR motif, on its antibacterial activity against healthcare-associated infections (HCAIs). Linear and branched peptides containing the RRWQWR motif were generated using solid phase peptide synthesis-Fmoc/tBu methodology, purified, and characterized using reverse phase-high performance liquid chromatography and matrix-assisted laser desorption/ionization time of flight mass spectrometry. For each peptide, the antibacterial activity against Staphylococcus aureus (ATCC 25923 and 33591 strains) and Klebsiella pneumoniae (ATCC 13883 and 700603 strains) was assessed by measuring the minimum inhibitory and the minimum bactericidal concentrations, in the exponential phase. Cells were observed by scanning electron microscopy, and the hemolytic activity of the peptides was assessed. The overall results demonstrate that, compared to linear analogues, polyvalent presentation of the RRWQWR motif enhances its antibacterial activity against both Gram-negative and Gram-positive bacteria even on resistant strain.
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379
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Knighton SC, Dolansky M, Donskey C, Warner C, Rai H, Higgins PA. Use of a verbal electronic audio reminder with a patient hand hygiene bundle to increase independent patient hand hygiene practices of older adults in an acute care setting. Am J Infect Control 2018; 46:610-616. [PMID: 29502883 DOI: 10.1016/j.ajic.2018.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 12/29/2017] [Accepted: 01/02/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND We hypothesized that the addition of a novel verbal electronic audio reminder to an educational patient hand hygiene bundle would increase performance of self-managed patient hand hygiene. METHODS We conducted a 2-group comparative effectiveness study randomly assigning participants to patient hand hygiene bundle 1 (n = 41), which included a video, a handout, and a personalized verbal electronic audio reminder (EAR) that prompted hand cleansing at 3 meal times, or patient hand hygiene bundle 2 (n = 34), which included the identical video and handout, but not the EAR. The primary outcome was alcohol-based hand sanitizer use based on weighing bottles of hand sanitizer. RESULTS Participants that received the EAR averaged significantly more use of hand sanitizer product over the 3 days of the study (mean ± SD, 29.97 ± 17.13 g) than participants with no EAR (mean ± SD, 10.88 ± 9.27 g; t73 = 5.822; P ≤ .001). CONCLUSIONS The addition of a novel verbal EAR to a patient hand hygiene bundle resulted in a significant increase in patient hand hygiene performance. Our results suggest that simple audio technology can be used to improve patient self-management of hand hygiene. Future research is needed to determine if the technology can be used to promote other healthy behaviors, reduce infections, and improve patient-centered care without increasing the workload of health care workers.
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380
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De Vincenti L, Glasenapp Y, Cattò C, Villa F, Cappitelli F, Papenbrock J. Hindering the formation and promoting the dispersion of medical biofilms: non-lethal effects of seagrass extracts. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 18:168. [PMID: 29843708 PMCID: PMC5975390 DOI: 10.1186/s12906-018-2232-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 05/15/2018] [Indexed: 01/22/2023]
Abstract
BACKGROUND Biofilms have great significance in healthcare-associated infections owing to their inherent tolerance and resistance to antimicrobial therapies. New approaches to prevent and treat unwanted biofilms are urgently required. To this end, three seagrass species (Enhalus acoroides, Halophila ovalis and Halodule pinifolia) collected in Vietnam and in India were investigated for their effects in mediating non-lethal interactions on sessile bacterial (Escherichia coli) and fungal (Candida albicans) cultures. The present study was focused on anti-biofilm activities of seagrass extracts, without killing cells. METHODS Methanolic extracts were characterized, and major compounds were identified by MS/MS analysis. The antibiofilm properties of the seagrass extracts were tested at sub-lethal concentrations by using microtiter plate adhesion assay. The performance of the most promising extract was further investigated in elegant bioreactors to reproduce mature biofilms both at the solid/liquid and the solid/air interfaces. Dispersion and bioluminescent assays were carried out to decipher the mode of action of the bioactive extract. RESULTS It was shown that up to 100 ppm of crude extracts did not adversely affect microbial growth, nor do they act as a carbon and energy source for the selected microorganisms. Seagrass extracts appear to be more effective in deterring microbial adhesion on hydrophobic surfaces than on hydrophilic. The results revealed that non-lethal concentrations of E. acoroides leaf extract: i) reduce bacterial and fungal coverage by 60.9 and 73.9%, respectively; ii) affect bacterial biofilm maturation and promote dispersion, up to 70%, in fungal biofilm; iii) increase luminescence in Vibrio harveyi by 25.8%. The characterization of methanolic extracts showed the unique profile of the E. acoroides leaf extract. CONCLUSIONS E. acoroides leaf extract proved to be the most promising extract among those tested. Indeed, the selected non-lethal concentrations of E. acoroides leaf extract were found to exert an antibiofilm effect on C. albicans and E. coli biofilm in the first phase of biofilm genesis, opening up the possibility of developing preventive strategies to hinder the adhesion of microbial cells to surfaces. The leaf extract also affected the dispersion and maturation steps in C. albicans and E. coli respectively, suggesting an important role in cell signaling processes.
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Affiliation(s)
- Luca De Vincenti
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l’Ambiente, Università degli Studi di Milano, via Celoria 2, 20133 Milan, Italy
| | - Yvana Glasenapp
- Institute of Botany, Leibniz University Hannover, Herrenhäuserstr. 2, D-30419 Hannover, Germany
| | - Cristina Cattò
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l’Ambiente, Università degli Studi di Milano, via Celoria 2, 20133 Milan, Italy
| | - Federica Villa
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l’Ambiente, Università degli Studi di Milano, via Celoria 2, 20133 Milan, Italy
| | - Francesca Cappitelli
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l’Ambiente, Università degli Studi di Milano, via Celoria 2, 20133 Milan, Italy
| | - Jutta Papenbrock
- Institute of Botany, Leibniz University Hannover, Herrenhäuserstr. 2, D-30419 Hannover, Germany
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381
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Schmieden DT, Basalo Vázquez SJ, Sangüesa H, van der Does M, Idema T, Meyer AS. Printing of Patterned, Engineered E. coli Biofilms with a Low-Cost 3D Printer. ACS Synth Biol 2018; 7:1328-1337. [PMID: 29690761 DOI: 10.1021/acssynbio.7b00424] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biofilms can grow on virtually any surface available, with impacts ranging from endangering the lives of patients to degrading unwanted water contaminants. Biofilm research is challenging due to the high degree of biofilm heterogeneity. A method for the production of standardized, reproducible, and patterned biofilm-inspired materials could be a boon for biofilm research and allow for completely new engineering applications. Here, we present such a method, combining 3D printing with genetic engineering. We prototyped a low-cost 3D printer that prints bioink, a suspension of bacteria in a solution of alginate that solidifies on a calcium-containing substrate. We 3D-printed Escherichia coli in different shapes and in discrete layers, after which the cells survived in the printing matrix for at least 1 week. When printed bacteria were induced to form curli fibers, the major proteinaceous extracellular component of E. coli biofilms, they remained adherent to the printing substrate and stably spatially patterned even after treatment with a matrix-dissolving agent, indicating that a biofilm-mimicking structure had formed. This work is the first demonstration of patterned, biofilm-inspired living materials that are produced by genetic control over curli formation in combination with spatial control by 3D printing. These materials could be used as living, functional materials in applications such as water filtration, metal ion sequestration, or civil engineering, and potentially as standardizable models for certain curli-containing biofilms.
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Affiliation(s)
- Dominik T. Schmieden
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Samantha J. Basalo Vázquez
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Héctor Sangüesa
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Marit van der Does
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Timon Idema
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Anne S. Meyer
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
- Department of Molecular Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, The Netherlands
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382
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Geddes-McAlister J, Shapiro RS. New pathogens, new tricks: emerging, drug-resistant fungal pathogens and future prospects for antifungal therapeutics. Ann N Y Acad Sci 2018; 1435:57-78. [DOI: 10.1111/nyas.13739] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Jennifer Geddes-McAlister
- Department of Molecular and Cellular Biology; University of Guelph; Guelph Ontario Canada
- Department of Proteomics and Signal Transduction; Max Planck Institute of Biochemistry; Munich Germany
| | - Rebecca S. Shapiro
- Department of Molecular and Cellular Biology; University of Guelph; Guelph Ontario Canada
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383
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Mesrati I, Saidani M, Jemili M, Ferjeni S, Slim A, Boubaker IBB. Virulence determinants, biofilm production and antimicrobial susceptibility in Staphylococcus aureus causing device-associated infections in a Tunisian hospital. Int J Antimicrob Agents 2018; 52:922-929. [PMID: 29775684 DOI: 10.1016/j.ijantimicag.2018.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/22/2018] [Accepted: 05/07/2018] [Indexed: 11/19/2022]
Abstract
Staphylococcus aureus is a clinically relevant pathogen that causes device-related infections (DRI) driven by several virulence factors. This study characterized S. aureus isolates involved in DRI in Tunisian patients. Forty consecutive S. aureus strains causing DRI and 47 randomly selected S. aureus strains causing non-device-related infections (NDRI) were collected. All strains were screened phenotypically for antibiotic susceptibility and biofilm forming ability. They were investigated for accessory gene regulator (agr) types, biofilm encoding genes (icaADBC), adhesins, leukotoxins, toxic shock toxin, enterotoxins and exotoxins encoding genes by polymerase chain reaction. Meticillin-resistant S. aureus (MRSA) strains were further characterized by staphylococcal cassette chromosome mec (SCCmec) typing. MRSA rates among DRI and NDRI isolates were 23% and 49% (P=0.02), respectively. The DRI isolates formed biofilm more frequently (n=32) than the NDRI isolates (n=28) (P=0.04), with predominance of the moderate biofilm producer category (P=0.027). All biofilm-positive isolates except four harboured icaADBC genes. A significant difference was observed between DRI and NDRI isolates for fnbA (53-77%), spa (45-26%), sdrD (80-55%) and sen (33-11%) genes. DRI strains were agrI (48%) and agrII (30%) types, whereas NDRI strains were agrI (36%) and agrIII (43%) types. SCCmec type IV was carried by 50% of MRSA isolates. This study highlights the virulence potential displayed by S. aureus isolated from DRI in comparison with NDRI.
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Affiliation(s)
- I Mesrati
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory of Antimicrobial Resistance, Tunis, Tunisia.
| | - M Saidani
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory of Antimicrobial Resistance, Tunis, Tunisia; Charles Nicolle Hospital, Laboratory of Microbiology, Tunis, Tunisia
| | - M Jemili
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory of Antimicrobial Resistance, Tunis, Tunisia
| | - S Ferjeni
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory of Antimicrobial Resistance, Tunis, Tunisia
| | - A Slim
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory of Antimicrobial Resistance, Tunis, Tunisia; Charles Nicolle Hospital, Laboratory of Microbiology, Tunis, Tunisia
| | - I Boutiba-Ben Boubaker
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory of Antimicrobial Resistance, Tunis, Tunisia; Charles Nicolle Hospital, Laboratory of Microbiology, Tunis, Tunisia
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384
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Varnava KG, Reynisson J, Raghothama S, Sarojini V. Synthesis, antibacterial, and antibiofilm potential of human autophagy 16 polypeptide and analogues. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Jóhannes Reynisson
- School of Chemical SciencesThe University of AucklandAuckland New Zealand
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385
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Zander ZK, Chen P, Hsu YH, Dreger NZ, Savariau L, McRoy WC, Cerchiari AE, Chambers SD, Barton HA, Becker ML. Post-fabrication QAC-functionalized thermoplastic polyurethane for contact-killing catheter applications. Biomaterials 2018; 178:339-350. [PMID: 29784475 DOI: 10.1016/j.biomaterials.2018.05.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 04/27/2018] [Accepted: 05/04/2018] [Indexed: 01/29/2023]
Abstract
The use of catheters is ubiquitous in medicine and the incidence of infection remains unacceptably high despite numerous advances in functional surfaces and drug elution. Herein we report the use of a thermoplastic polyurethane containing an allyl ether side-chain functionality (allyl-TPU) that allows for rapid and convenient surface modification with antimicrobial reagents, post-processing. This post-processing functionalization affords the ability to target appropriate TPU properties and maintain the functional groups on the surface of the device where they do not affect bulk properties. A series of quaternary ammonium thiol compounds (Qx-SH) possessing various hydrocarbon tail lengths (8-14 carbons) were synthesized and attached to the surface using thiol-ene "click" chemistry. A quantitative assessment of the amount of Qx-SH available on the surface was determined using fluorescence spectroscopy and X-ray photoelectron spectroscopy (XPS). Contact-killing assays note the Q8-SH composition has the highest antimicrobial activity, and a live/dead fluorescence assay reveals rapid contact-killing of Staphylococcus aureus (>75% in 5 min) and Escherichia coli (90% in 10 min) inocula. Scale-up and extrusion of allyl-TPU provides catheter prototypes for biofilm formation testing with Pseudomonas aeruginosa, and surface-functionalized catheters modified with Q8-SH demonstrate their ability to reduce biofilm formation.
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Affiliation(s)
- Zachary K Zander
- Department of Polymer Science, University of Akron, Akron, OH 44325, United States
| | - Peiru Chen
- Department of Polymer Science, University of Akron, Akron, OH 44325, United States
| | - Yen-Hao Hsu
- Department of Polymer Science, University of Akron, Akron, OH 44325, United States
| | - Nathan Z Dreger
- Department of Polymer Science, University of Akron, Akron, OH 44325, United States
| | - Laura Savariau
- Department of Polymer Science, University of Akron, Akron, OH 44325, United States
| | - Willie C McRoy
- Cook Research Inc., West Lafayette, IN 47906, United States
| | | | | | - Hazel A Barton
- Department of Biology, University of Akron, Akron, OH 44325, United States
| | - Matthew L Becker
- Department of Polymer Science, University of Akron, Akron, OH 44325, United States.
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386
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Manner S, Fallarero A. Screening of Natural Product Derivatives Identifies Two Structurally Related Flavonoids as Potent Quorum Sensing Inhibitors against Gram-Negative Bacteria. Int J Mol Sci 2018; 19:ijms19051346. [PMID: 29751512 PMCID: PMC5983823 DOI: 10.3390/ijms19051346] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 04/28/2018] [Accepted: 04/30/2018] [Indexed: 01/14/2023] Open
Abstract
Owing to the failure of conventional antibiotics in biofilm control, alternative approaches are urgently needed. Inhibition of quorum sensing (QS) represents an attractive target since it is involved in several processes essential for biofilm formation. In this study, a compound library of natural product derivatives (n = 3040) was screened for anti-quorum sensing activity using Chromobacterium violaceum as reporter bacteria. Screening assays, based on QS-mediated violacein production and viability, were performed in parallel to identify non-bactericidal QS inhibitors (QSIs). Nine highly active QSIs were identified, while 328 compounds were classified as moderately actives and 2062 compounds as inactives. Re-testing of the highly actives at a lower concentration against C. violaceum, complemented by a literature search, led to the identification of two flavonoid derivatives as the most potent QSIs, and their impact on biofilm maturation in Escherichia coli and Pseudomonas aeruginosa was further investigated. Finally, effects of these leads on swimming and swarming motility of P. aeruginosa were quantified. The identified flavonoids affected all the studied QS-related functions at micromolar concentrations. These compounds can serve as starting points for further optimization and development of more potent QSIs as adjunctive agents used with antibiotics in the treatment of biofilms.
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Affiliation(s)
- Suvi Manner
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6A, FI-20520 Turku, Finland.
| | - Adyary Fallarero
- Pharmaceutical Design and Discovery (PharmDD), Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, FI-00014 Helsinki, Finland.
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387
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Surface characteristics and antimicrobial properties of modified catheter surfaces by polypyrogallol and metal ions. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 90:673-684. [PMID: 29853139 DOI: 10.1016/j.msec.2018.04.095] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 03/29/2018] [Accepted: 04/30/2018] [Indexed: 12/15/2022]
Abstract
Catheter associated infections (CAIs) are the major cause of nosocomial infections leading to increased morbidity, mortality rates and economical loss. Though the antibiotic coated surface modified catheters are reported to be effective in preventing CAIs, presence of sub-lethal concentrations of antibiotics in long term instilled catheters poses a risk of development and spread of drug resistant microbial strains. Herein, we have developed an antibiotic-free alternative strategy to coat catheter surfaces using pyrogallol (PG) and metal ions (Ag+/Mg2+). Surface characteristics, antimicrobial and anti-biofilm properties with hemocompatibility of the coated catheters were studied. Structural characteristics of coated catheters were similar to the uncoated catheters with improved wettability. All the coated catheters with PG and different PG/metal ion combinations exhibited broad spectrum antibacterial activity. Catheters coated with PG/metal ions combination showed effective antibiofilm properties against MRSA strains. None of the coated catheters showed any significant hemolysis for rabbit erythrocytes. In addition, polypyrogallol (pPG) coating attenuated the hemolytic properties of silver without altering the antimicrobial properties. The inherent antimicrobial properties of the coating agent along with antimicrobial metal ions broaden the application landscape which includes coating of other medical devices, clean room construction and development of antimicrobial surfaces. The chemical formulation can also be used to design antiseptic solutions to prevent healthcare associated infections.
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388
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Boyer CJ, Ambrose J, Das S, Humayun A, Chappidi D, Giorno R, Mills DK. Antibacterial and antibiofouling clay nanotube-silicone composite. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2018; 11:123-137. [PMID: 29713206 PMCID: PMC5907789 DOI: 10.2147/mder.s146248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction Invasive medical devices are used in treating millions of patients each day. Bacterial adherence to their surface is an early step in biofilm formation that may lead to infection, health complications, longer hospital stays, and death. Prevention of bacterial adherence and biofilm development continues to be a major healthcare challenge. Accordingly, there is a pressing need to improve the anti-microbial properties of medical devices. Materials and Methods Polydimethylsiloxane (PDMS) was doped with halloysite nanotubes (HNTs), and the PDMS-HNT composite surfaces were coated with PDMS-b-polyethylene oxide (PEO) and antibacterials. The composite material properties were examined using SEM, energy dispersive spectroscopy, water contact angle measurements, tensile testing, UV-Vis spectroscopy, and thermal gravimetric analysis. The antibacterial potential of the PDMS-HNT composites was compared to commercial urinary catheters using cultures of E. coli and S. aureus. Fibrinogen adsorption studies were also performed on the PDMS-HNT-PEO composites. Results HNT addition increased drug load during solvent swelling without reducing material strength. The hydrophilic properties provided by PEO were maintained after HNT addition, and the composites displayed protein-repelling properties. Additionally, composites showed superiority over commercial catheters at inhibiting bacterial growth. Conclusion PDMS-HNT composites showed superiority regarding their efficacy at inhibiting bacterial growth, in comparison to commercial antibacterial catheters. Our data suggest that PDMS-HNT composites have potential as a coating material for anti-bacterial invasive devices and in the prevention of institutional-acquired infections.
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Affiliation(s)
- C J Boyer
- Molecular Science and Nanotechnology, College of Engineering & Science, Louisiana Tech University, Ruston, LA, USA
| | - J Ambrose
- Center for Biomedical Engineering and Rehabilitation Science, Louisiana Tech University, Ruston, LA, USA
| | - S Das
- Molecular Science and Nanotechnology, College of Engineering & Science, Louisiana Tech University, Ruston, LA, USA
| | - A Humayun
- Molecular Science and Nanotechnology, College of Engineering & Science, Louisiana Tech University, Ruston, LA, USA
| | - D Chappidi
- Molecular Science and Nanotechnology, College of Engineering & Science, Louisiana Tech University, Ruston, LA, USA
| | - R Giorno
- School of Biological Sciences, Louisiana Tech University, Ruston, LA, USA
| | - D K Mills
- Center for Biomedical Engineering and Rehabilitation Science, Louisiana Tech University, Ruston, LA, USA.,School of Biological Sciences, Louisiana Tech University, Ruston, LA, USA
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389
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McOwat K, Stanley-Wall NR. Biofilm Building: A Simple Board Game to Reinforce Knowledge of Biofilm Formation. JOURNAL OF MICROBIOLOGY & BIOLOGY EDUCATION 2018; 19:jmbe-19-59. [PMID: 29904559 PMCID: PMC5969445 DOI: 10.1128/jmbe.v19i1.1355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 01/31/2018] [Indexed: 06/08/2023]
Abstract
The increasing risk of antibiotic resistance and correlating decrease in effective clinical treatments is a serious issue worldwide. One source antibiotic tolerance derives from biofilm infections: collectives of bacteria surrounded by an extracellular matrix that adhere to surfaces. Here we outline a board game designed to raise awareness and knowledge of biofilms in young learners.
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Affiliation(s)
| | - Nicola R. Stanley-Wall
- Corresponding author. Mailing address: Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH UK. Phone: +44(0)1382 385136. Fax: +44(0)1382 388216. E-mail:
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390
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Lima JLDC, Alves LR, Jacomé PRLDA, Bezerra Neto JP, Maciel MAV, Morais MMCD. Biofilm production by clinical isolates of Pseudomonas aeruginosa and structural changes in LasR protein of isolates non biofilm-producing. Braz J Infect Dis 2018; 22:129-136. [PMID: 29601791 PMCID: PMC9428190 DOI: 10.1016/j.bjid.2018.03.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 03/07/2018] [Accepted: 03/13/2018] [Indexed: 12/16/2022] Open
Abstract
Introduction Biofilm production is an important mechanism for the survival of Pseudomonas aeruginosa and its relationship with antimicrobial resistance represents a challenge for patient therapeutics. P. aeruginosa is an opportunistic pathogen frequently associated to nosocomial infections, especially in imunocompromised hosts. Objectives Analyze the phenotypic biofilm production in P. aeruginosa isolates, describe clonal profiles, and analyze quorum sensing (QS) genes and the occurrence of mutations in the LasR protein of non-biofilm producing isolates. Methods Isolates were tested for biofilm production by measuring cells adherence to the microtiter plates. Clonal profile analysis was carried out through ERIC-PCR, QS genes were by specific PCR. Results The results showed that 77.5% of the isolates were considered biofilm producers. The results of genotyping showed 38 distinct genetic profiles. As for the occurrence of the genes, 100% of the isolates presented the lasR, rhlI and rhlR genes, and 97.5%, presented the lasI gene. In this study nine isolates were not biofilm producers. However, all presented the QS genes. Amplicons related to genes were sequenced in three of the nine non-biofilm-producing isolates (all presenting different genetic similarity profile) and aligned to the sequences of those genes in P. aeruginosa strain PAO1 (standard biofilm-producing strain). Alignment analysis showed an insertion of three nucleotides (T, C and G) causing the addition of an amino acid valine in the sequence of the LasR protein, in position 53. Conclusion The modeling of the resulting LasR protein showed a conformational change in its structure, suggesting that this might be the reason why these isolates are unable to produce biofilm.
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Affiliation(s)
- Jailton Lobo da Costa Lima
- Universidade de Pernambuco (UPE), Instituto de Ciências Biológicas, Programa de Pós-graduação em Biologia Celular e Molecular Aplicada, Recife, PE, Brazil; Universidade Federal de Pernambuco, Departamento de Medicina Tropical, Programa de Pós-Graduação em Medicina Tropical, Recife, PE, Brazil.
| | - Lilian Rodrigues Alves
- Universidade Federal de Pernambuco, Departamento de Medicina Tropical, Programa de Pós-Graduação em Medicina Tropical, Recife, PE, Brazil
| | - Paula Regina Luna de Araújo Jacomé
- Universidade Federal de Pernambuco, Departamento de Medicina Tropical, Programa de Pós-Graduação em Medicina Tropical, Recife, PE, Brazil
| | | | - Maria Amélia Vieira Maciel
- Universidade Federal de Pernambuco, Departamento de Medicina Tropical, Programa de Pós-Graduação em Medicina Tropical, Recife, PE, Brazil
| | - Marcia Maria Camargo de Morais
- Universidade de Pernambuco (UPE), Instituto de Ciências Biológicas, Programa de Pós-graduação em Biologia Celular e Molecular Aplicada, Recife, PE, Brazil
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391
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Asymmetric adhesion of rod-shaped bacteria controls microcolony morphogenesis. Nat Commun 2018; 9:1120. [PMID: 29549338 PMCID: PMC5856753 DOI: 10.1038/s41467-018-03446-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 02/14/2018] [Indexed: 12/29/2022] Open
Abstract
Surface colonization underpins microbial ecology on terrestrial environments. Although factors that mediate bacteria–substrate adhesion have been extensively studied, their spatiotemporal dynamics during the establishment of microcolonies remains largely unexplored. Here, we use laser ablation and force microscopy to monitor single-cell adhesion during the course of microcolony formation. We find that adhesion forces of the rod-shaped bacteria Escherichia coli and Pseudomonas aeruginosa are polar. This asymmetry induces mechanical tension, and drives daughter cell rearrangements, which eventually determine the shape of the microcolonies. Informed by experimental data, we develop a quantitative model of microcolony morphogenesis that enables the prediction of bacterial adhesion strength from simple time-lapse measurements. Our results demonstrate how patterns of surface colonization derive from the spatial distribution of adhesive factors on the cell envelope. It is unclear how cell adhesion and elongation coordinate during formation of bacterial microcolonies. Here, Duvernoy et al. monitor microcolony formation in rod-shaped bacteria, and show that patterns of surface colonization derive from the spatial distribution of adhesive factors on the cell envelope.
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392
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Sharma S, Chaudhry V, Kumar S, Patil PB. Phylogenomic Based Comparative Studies on Indian and American Commensal Staphylococcus epidermidis Isolates. Front Microbiol 2018. [PMID: 29535698 PMCID: PMC5835047 DOI: 10.3389/fmicb.2018.00333] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus epidermidis is a prominent commensal member of human skin microbiome and an emerging nosocomial pathogen, making it a good model organism to provide genomic insights, correlating its transition between commensalism and pathogenicity. While there are numerous studies to understand differences in commensal and pathogenic isolates, systematic efforts to understand variation and evolutionary pattern in multiple strains isolated from healthy individuals are lacking. In the present study, using whole genome sequencing and analysis, we report presence of diverse lineages of S. epidermidis isolates in healthy individuals from two geographically diverse locations of India and North America. Further, there is distinct pattern in the distribution of candidate gene(s) for pathogenicity and commensalism. The pattern is not only reflected in lineages but is also based on geographic origin of the isolates. This is evident by the fact that North American isolates under this study are more genomically dynamic and harbor pathogenicity markers in higher frequency. On the other hand, isolates of Indian origin are less genomically dynamic, harbor less pathogenicity marker genes and possess two unique antimicrobial peptide gene clusters. This study provides a basis to understand the nature of selection pressure in a key human skin commensal bacterium with implications in its management as an opportunistic pathogen.
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Affiliation(s)
- Shikha Sharma
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Vasvi Chaudhry
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Sanjeet Kumar
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Prabhu B Patil
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
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393
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Thet NT, Wallace L, Wibaux A, Boote N, Jenkins ATA. Development of a mixed-species biofilm model and its virulence implications in device related infections. J Biomed Mater Res B Appl Biomater 2018. [PMID: 29520965 DOI: 10.1002/jbm.b.34103] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
It is becoming increasingly accepted that to understand and model the bacterial colonization and infection of abiotic surfaces requires the use of a biofilm model. There are many bacterial colonizations by at least two primary species, however this is difficult to model in vitro. This study reports the development of a simple mixed-species biofilm model using strains of two clinically significant bacteria: Staphylococcus aureus and Pseudomonas aeruginosa grown on nanoporous polycarbonate membranes on nutrient agar support. Scanning electron microscopy revealed the complex biofilm characteristics of two bacteria blending in extensive extracellular matrices. Using a prototype wound dressing which detects cytolytic virulence factors, the virulence secretion of 30 single and 40 mixed-species biofilms was tested. P. aeruginosa was seen to out-compete S. aureus, resulting in a biofilm with P. aeruginosa dominating. In situ growth of mixed-species biofilm under prototype dressings showed a real-time correlation between the viable biofilm population and their associated virulence factors, as seen by dressing fluorescent assay. This paper aims to provide a protocol for scientists working in the field of device related infection to create mixed-species biofilms and demonstrate that such biofilms are persistently more virulent in real infections. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 129-137, 2019.
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Affiliation(s)
- Naing T Thet
- Department of Chemistry, University of Bath, BA2 7AY, Bath, UK
| | - Laura Wallace
- Department of Chemistry, University of Bath, BA2 7AY, Bath, UK
| | - Anne Wibaux
- Scapa Healthcare, Hilldrop Lane, Ramsbury, Marlborough, SN8 2RB, UK
| | - Nick Boote
- Scapa Healthcare, Hilldrop Lane, Ramsbury, Marlborough, SN8 2RB, UK
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394
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Vega SC, Martínez DA, Chalá MDS, Vargas HA, Rosas JE. Design, Synthesis and Evaluation of Branched RRWQWR-Based Peptides as Antibacterial Agents Against Clinically Relevant Gram-Positive and Gram-Negative Pathogens. Front Microbiol 2018; 9:329. [PMID: 29551999 PMCID: PMC5840262 DOI: 10.3389/fmicb.2018.00329] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/12/2018] [Indexed: 12/19/2022] Open
Abstract
Multidrug resistance of pathogenic bacteria has become a public health crisis that requires the urgent design of new antibacterial drugs such as antimicrobial peptides (AMPs). Seeking to obtain new, lactoferricin B (LfcinB)-based synthetic peptides as viable early-stage candidates for future development as AMPs against clinically relevant bacteria, we designed, synthesized and screened three new cationic peptides derived from bovine LfcinB. These peptides contain at least one RRWQWR motif and differ by the copy number (monomeric, dimeric or tetrameric) and structure (linear or branched) of this motif. They comprise a linear palindromic peptide (RWQWRWQWR), a dimeric peptide (RRWQWR)2KAhx and a tetrameric peptide (RRWQWR)4K2Ahx2C2. They were screened for antibacterial activity against Enterococcus faecalis (ATCC 29212 and ATCC 51575 strains), Pseudomonas aeruginosa (ATCC 10145 and ATCC 27853 strains) and clinical isolates of two Gram-positive bacteria (Enterococcus faecium and Staphylococcus aureus) and two Gram-negative bacteria (Klebsiella pneumoniae and Pseudomonas aeruginosa). All three peptides exhibited greater activity than did the reference peptide, LfcinB (17-31), which contains a single linear RRWQWR motif. Against the ATCC reference strains, the three new peptides exhibited minimum inhibitory concentration (MIC50) values of 3.1-198.0 μM and minimum bactericidal concentration (MBC) values of 25-200 μM, and against the clinical isolates, MIC50 values of 1.6-75.0 μM and MBC values of 12.5-100 μM. However, the tetrameric peptide was also found to be strongly hemolytic (49.1% at 100 μM). Scanning Electron Microscopy (SEM) demonstrated that in the dimeric and tetrameric peptides, the RRWQWR motif is exposed to the pathogen surface. Our results may inform the design of new, RRWQWR-based AMPs.
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Affiliation(s)
- Sandra C Vega
- Department of Pharmacy, Faculty of Science, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Diana A Martínez
- Department of Pharmacy, Faculty of Science, Universidad Nacional de Colombia, Bogotá, Colombia
| | - María Del S Chalá
- Laboratory of Public Health, Secretaria Distrital de Salud, Bogotá, Colombia
| | - Hernán A Vargas
- Laboratory of Public Health, Secretaria Distrital de Salud, Bogotá, Colombia
| | - Jaiver E Rosas
- Department of Pharmacy, Faculty of Science, Universidad Nacional de Colombia, Bogotá, Colombia
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395
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Mesoporous silica nanoparticles as diagnostic and therapeutic tools: how can they combat bacterial infection? Ther Deliv 2018; 9:241-244. [PMID: 29495945 DOI: 10.4155/tde-2017-0111] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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396
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Okuda KI, Nagahori R, Yamada S, Sugimoto S, Sato C, Sato M, Iwase T, Hashimoto K, Mizunoe Y. The Composition and Structure of Biofilms Developed by Propionibacterium acnes Isolated from Cardiac Pacemaker Devices. Front Microbiol 2018; 9:182. [PMID: 29491850 PMCID: PMC5817082 DOI: 10.3389/fmicb.2018.00182] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/26/2018] [Indexed: 11/13/2022] Open
Abstract
The present study aimed to understand the biofilm formation mechanism of Propionibacterium acnes by analyzing the components and structure of the biofilms. P. acnes strains were isolated from the surface of explanted cardiac pacemaker devices that exhibited no clinical signs of infection. Culture tests using a simple stamp culture method (pressing pacemakers against the surface of agar plates) revealed frequent P. acnes colonization on the surface of cardiac pacemaker devices. P. acnes was isolated from 7/31 devices, and the isolates were categorized by multilocus sequence typing into five different sequence types (STs): ST4 (JK18.2), ST53 (JK17.1), ST69 (JK12.2 and JK13.1), ST124 (JK5.3), ST125 (JK6.2), and unknown ST (JK19.3). An in vitro biofilm formation assay using microtiter plates demonstrated that 5/7 isolates formed biofilms. Inhibitory effects of DNase I and proteinase K on biofilm formation varied among isolates. In contrast, dispersin B showed no inhibitory activity against all isolates. Three-dimensional live/dead imaging of P. acnes biofilms with different biochemical properties using confocal laser microscopy demonstrated different distributions and proportions of living and dead cells. Additionally, it was suggested that extracellular DNA (eDNA) plays a role in the formation of biofilms containing living cells. Ultrastructural analysis of P. acnes biofilms using a transmission electron microscope and atmospheric scanning electron microscope revealed leakage of cytoplasmic components along with cell lysis and fibrous structures of eDNA connecting cells. In conclusion, the biochemical properties and structures of the biofilms differed among P. acnes isolates. These findings may provide clues for establishing countermeasures against biofilm-associated infection by P. acnes.
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Affiliation(s)
- Ken-Ichi Okuda
- Department of Bacteriology, The Jikei University School of Medicine, Tokyo, Japan.,Jikei Center for Biofilm Science and Technology, Tokyo, Japan
| | - Ryuichi Nagahori
- Department of Cardiac Surgery, The Jikei University School of Medicine, Tokyo, Japan
| | - Satomi Yamada
- Department of Bacteriology, The Jikei University School of Medicine, Tokyo, Japan
| | - Shinya Sugimoto
- Department of Bacteriology, The Jikei University School of Medicine, Tokyo, Japan.,Jikei Center for Biofilm Science and Technology, Tokyo, Japan
| | - Chikara Sato
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Mari Sato
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Tadayuki Iwase
- Department of Bacteriology, The Jikei University School of Medicine, Tokyo, Japan.,Jikei Center for Biofilm Science and Technology, Tokyo, Japan
| | - Kazuhiro Hashimoto
- Department of Cardiac Surgery, The Jikei University School of Medicine, Tokyo, Japan
| | - Yoshimitsu Mizunoe
- Department of Bacteriology, The Jikei University School of Medicine, Tokyo, Japan.,Jikei Center for Biofilm Science and Technology, Tokyo, Japan
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397
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Zander ZK, Becker ML. Antimicrobial and Antifouling Strategies for Polymeric Medical Devices. ACS Macro Lett 2018; 7:16-25. [PMID: 35610930 DOI: 10.1021/acsmacrolett.7b00879] [Citation(s) in RCA: 153] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Hospital-acquired infections arising from implanted polymeric medical devices continue to pose a significant challenge for medical professionals and patients. Often times, these infections arise from biofilm accumulation on the device, which is difficult to eradicate and usually requires antibiotic treatment and device removal. In response, significant efforts have been made to design functional polymeric devices or coatings that possess antimicrobial or antifouling properties that limit biofilm formation and subsequent infection by inhibiting or eliminating bacteria near the device surface or by limiting the initial attachment of proteins and bacteria. In this Viewpoint, we highlight the magnitude of device-associated infections, the role of biofilm formation in human pathogenesis, and recent advances in antimicrobial and antifouling polymers, as well as current strategies employed in commercial devices for preventing infection.
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Affiliation(s)
- Zachary K. Zander
- Department of Polymer Science, The University of Akron, 170 University Ave, Akron, Ohio 44325-3909, United States
| | - Matthew L. Becker
- Department of Polymer Science, The University of Akron, 170 University Ave, Akron, Ohio 44325-3909, United States
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398
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Morse DJ, Wilson MJ, Wei X, Lewis MAO, Bradshaw DJ, Murdoch C, Williams DW. Denture-associated biofilm infection in three-dimensional oral mucosal tissue models. J Med Microbiol 2018; 67:364-375. [PMID: 29458673 PMCID: PMC5882079 DOI: 10.1099/jmm.0.000677] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Purpose In vitro analyses of virulence, pathogenicity and associated host cell responses are important components in the study of biofilm infections. The Candida-related infection, denture-associated oral candidosis, affects up to 60 % of denture wearers and manifests as inflammation of palatal tissues contacting the denture-fitting surface. Commercially available three-dimensional tissue models can be used to study infection, but their use is limited for many academic research institutions, primarily because of the substantial purchase costs. The aim of this study was to develop and evaluate the use of in vitro tissue models to assess infections by biofilms on acrylic surfaces through tissue damage and Candida albicans virulence gene expression. Methodology In vitro models were compared against commercially available tissue equivalents (keratinocyte-only, SkinEthic; full-thickness, MatTek Corporation). An in vitro keratinocyte-only tissue was produced using a cancer-derived cell line, TR146, and a full-thickness model incorporating primary fibroblasts and immortalised normal oral keratinocytes was also generated. The in vitro full-thickness tissues incorporated keratinocytes and fibroblasts, and have potential for future further development and analysis. Results Following polymicrobial infection with biofilms on acrylic surfaces, both in-house developed models were shown to provide equivalent results to the SkinEthic and MatTek models in terms of tissue damage: a significant (P<0.05) increase in LDH activity for mixed species biofilms compared to uninfected control, and no significant difference (P>0.05) in the expression of most C. albicans virulence genes when comparing tissue models of the same type. Conclusion Our results confirm the feasibility and suitability of using these alternative in vitro tissue models for such analyses.
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Affiliation(s)
- Daniel J Morse
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, UK
| | - Melanie J Wilson
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, UK
| | - Xiaoqing Wei
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, UK
| | - Michael A O Lewis
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, UK
| | | | - Craig Murdoch
- School of Clinical Dentistry, University of Sheffield, Sheffield, UK
| | - David W Williams
- Oral and Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff, UK
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399
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Kemme M, Heinzel-Wieland R. Quantitative Assessment of Antimicrobial Activity of PLGA Films Loaded with 4-Hexylresorcinol. J Funct Biomater 2018; 9:E4. [PMID: 29324696 PMCID: PMC5872090 DOI: 10.3390/jfb9010004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 11/17/2022] Open
Abstract
Profound screening and evaluation methods for biocide-releasing polymer films are crucial for predicting applicability and therapeutic outcome of these drug delivery systems. For this purpose, we developed an agar overlay assay embedding biopolymer composite films in a seeded microbial lawn. By combining this approach with model-dependent analysis for agar diffusion, antimicrobial potency of the entrapped drug can be calculated in terms of minimum inhibitory concentrations (MICs). Thus, the topical antiseptic 4-hexylresorcinol (4-HR) was incorporated into poly(lactic-co-glycolic acid) (PLGA) films at different loadings up to 3.7 mg/cm² surface area through a solvent casting technique. The antimicrobial activity of 4-HR released from these composite films was assessed against a panel of Gram-negative and Gram-positive bacteria, yeasts and filamentous fungi by the proposed assay. All the microbial strains tested were susceptible to PLGA-4-HR films with MIC values down to 0.4% (w/w). The presented approach serves as a reliable method in screening and quantifying the antimicrobial activity of polymer composite films. Moreover, 4-HR-loaded PLGA films are a promising biomaterial that may find future application in the biomedical and packaging sector.
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Affiliation(s)
- Michael Kemme
- Department of Chemical Engineering and Biotechnology, Hochschule Darmstadt, University of Applied Sciences, Stephanstrasse 7, 64295 Darmstadt, Germany.
| | - Regina Heinzel-Wieland
- Department of Chemical Engineering and Biotechnology, Hochschule Darmstadt, University of Applied Sciences, Stephanstrasse 7, 64295 Darmstadt, Germany.
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400
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Chang CY. Surface Sensing for Biofilm Formation in Pseudomonas aeruginosa. Front Microbiol 2018; 8:2671. [PMID: 29375533 PMCID: PMC5767216 DOI: 10.3389/fmicb.2017.02671] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/21/2017] [Indexed: 11/13/2022] Open
Abstract
Aggregating and forming biofilms on biotic or abiotic surfaces are ubiquitous bacterial behaviors under various conditions. In clinical settings, persistent presence of biofilms increases the risks of healthcare-associated infections and imposes huge healthcare and economic burdens. Bacteria within biofilms are protected from external damage and attacks from the host immune system and can exchange genomic information including antibiotic-resistance genes. Dispersed bacterial cells from attached biofilms on medical devices or host tissues may also serve as the origin of further infections. Understanding how bacteria develop biofilms is pertinent to tackle biofilm-associated infections and transmission. Biofilms have been suggested as a continuum of growth modes for adapting to different environments, initiating from bacterial cells sensing their attachment to a surface and then switching cellular physiological status for mature biofilm development. It is crucial to understand bacterial gene regulatory networks and decision-making processes for biofilm formation upon initial surface attachment. Pseudomonas aeruginosa is one of the model microorganisms for studying bacterial population behaviors. Several hypotheses and studies have suggested that extracellular macromolecules and appendages play important roles in bacterial responses to the surface attachment. Here, I review recent studies on potential molecular mechanisms and signal transduction pathways for P. aeruginosa surface sensing.
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Affiliation(s)
- Chien-Yi Chang
- School of Chemistry and Biosciences, University of Bradford, Bradford, United Kingdom
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