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Bhutta MF, Leach AJ, Brennan-Jones CG. Chronic suppurative otitis media. Lancet 2024; 403:2339-2348. [PMID: 38621397 DOI: 10.1016/s0140-6736(24)00259-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 12/12/2023] [Accepted: 02/08/2024] [Indexed: 04/17/2024]
Abstract
Chronic suppurative otitis media (CSOM) is a leading global cause of potentially preventable hearing loss in children and adults, associated with socioeconomic deprivation. There is an absence of consensus on the definition of CSOM, which complicates efforts for prevention, treatment, and monitoring. CSOM occurs when perforation of the tympanic membrane is associated with severe or persistent inflammation in the middle ear, leading to hearing loss and recurrent or persistent ear discharge (otorrhoea). Cholesteatoma, caused by the inward growth of the squamous epithelium of the tympanic membrane into the middle ear, can also occur. The optimal treatment of discharge in CSOM is topical antibiotics. In resource-limited settings where topical antibiotics might not be available, topical antiseptics are an alternative. For persistent disease, surgery to repair the tympanic membrane or remove cholesteatoma might offer long-term resolution of otorrhoea and potential improvement to hearing. Recent developments in self-fitted air-conduction and bone-conduction hearing aids offer promise as new options for rehabilitation.
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Affiliation(s)
- Mahmood F Bhutta
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton, UK; Department of ENT, Royal Sussex County Hospital, Brighton, UK.
| | - Amanda J Leach
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Casuarina, Darwin, NT, Australia
| | - Christopher G Brennan-Jones
- School of Allied Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia; Ear Health Group, Telethon Kids Institute, University of Western Australia, Perth, WA, Australia
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2
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Zafer MM, Mohamed GA, Ibrahim SRM, Ghosh S, Bornman C, Elfaky MA. Biofilm-mediated infections by multidrug-resistant microbes: a comprehensive exploration and forward perspectives. Arch Microbiol 2024; 206:101. [PMID: 38353831 PMCID: PMC10867068 DOI: 10.1007/s00203-023-03826-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 12/30/2023] [Indexed: 02/16/2024]
Abstract
A biofilm is a collection of microorganisms organized in a matrix of extracellular polymeric material. Biofilms consist of microbial cells that attach to both surfaces and each other, whether they are living or non-living. These microbial biofilms can lead to hospital-acquired infections and are generally detrimental. They possess the ability to resist the human immune system and antibiotics. The National Institute of Health (NIH) states that biofilm formation is associated with 65% of all microbial illnesses and 80% of chronic illnesses. Additionally, non-device-related microbial biofilm infections include conditions like cystic fibrosis, otitis media, infective endocarditis, and chronic inflammatory disorders. This review aims to provide an overview of research on chronic infections caused by microbial biofilms, methods used for biofilm detection, recent approaches to combat biofilms, and future perspectives, including the development of innovative antimicrobial strategies such as antimicrobial peptides, bacteriophages, and agents that disrupt biofilms.
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Affiliation(s)
- Mai M Zafer
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ahram Canadian University, Cairo, Egypt.
| | - Gamal A Mohamed
- Department of Natural Products and Alternative Medicine, Faculty of Pharmacy, King Abdulaziz University, 21589, Jeddah, Saudi Arabia
| | - Sabrin R M Ibrahim
- Department of Chemistry, Preparatory Year Program, Batterjee Medical College, 21442, Jeddah, Saudi Arabia
- Department of Pharmacognosy, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt
| | - Soumya Ghosh
- Natural and Medical Science Research Center, University of Nizwa, Nizwa, 616, Oman
| | - Charné Bornman
- Department of Engineering Sciences, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, 9301, South Africa
| | - Mahmoud A Elfaky
- Department of Natural Products and Alternative Medicine, Faculty of Pharmacy, King Abdulaziz University, 21589, Jeddah, Saudi Arabia.
- Center for Artificial Intelligence in Precision Medicine, King Abdulaziz University, 21589, Jeddah, Saudi Arabia.
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Elzayat S, El-Deeb ME, El-Shirbeny HA, El-Shirbiny H, Abdel-Maboud M, Nasr K. The Prevalence and Association of Biofilms With Otitis Media With Effusion: A Systematic Review and Meta-Analysis. Ann Otol Rhinol Laryngol 2024; 133:229-238. [PMID: 37553806 DOI: 10.1177/00034894231188855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
PURPOSE We aimed to identify the role of bacterial biofilms in the chronicity of otitis media with effusion and its resistance to antibiotics. We illustrated this role by reviewing, analyzing, and correlating the findings with the results of the included studies to reach clear evidence. METHODS A comprehensive search of electronic databases (Scopus, PubMed, Web of Science, Cochrane, and GHL databases) was performed for all studies using the following strategy till April 2021 with the search terms: Biofilm and Middle ear effusion. We found 935 references, 421 were duplicates, and 514 were needed for further screening, and it was as follows: PubMed 215, Scopus 18, Cochrane 130, Web of Science 136, and GHL 15. RESULTS The pooled prevalence of culture-positive effusions was estimated to be 40% (95% CI [28%, 53%]) of the total OME population. Overall, the prevalence of PCR-positive effusions was estimated to be 97% (95% CI [95%, 99%]) of the total OME population. The pooled prevalence of EM-positive effusions was estimated to be 82% (95% CI [69%, 95%]) of the total OME population. CONCLUSION The data presented in this study coincide with the significant role of bacterial biofilms in the pathogenesis of chronic otitis media with effusion. The involvement of bacterial biofilm as a component of the OME pathogenic process can help us to explain why antimicrobial therapy is not always effective in the eradication of the disease process and, also explain the recurrence of middle ear effusion after treatment with tympanostomy tubes either with or without adenoidectomy.
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Affiliation(s)
- Saad Elzayat
- Department of Otorhinolaryngology, Faculty of Medicine-Kafrelsheikh University, Kafrelsheikh, Egypt
| | - Mohamed E El-Deeb
- Department of Otorhinolaryngology, Faculty of Medicine-Kafrelsheikh University, Kafrelsheikh, Egypt
| | - Hussein A El-Shirbeny
- Department of Otorhinolaryngology, Faculty of Medicine-Kafrelsheikh University, Kafrelsheikh, Egypt
| | | | | | - Khaled Nasr
- Department of Otorhinolaryngology, Faculty of Medicine-Kafrelsheikh University, Kafrelsheikh, Egypt
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Kragh KN, Tolker-Nielsen T, Lichtenberg M. The non-attached biofilm aggregate. Commun Biol 2023; 6:898. [PMID: 37658117 PMCID: PMC10474055 DOI: 10.1038/s42003-023-05281-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 08/24/2023] [Indexed: 09/03/2023] Open
Abstract
Biofilms have conventionally been perceived as dense bacterial masses on surfaces, following the five-step model of development. Initial biofilm research focused on surface-attached formations, but detached aggregates have received increasing attention in the past decade due to their pivotal role in chronic infections. Understanding their nature sparked fervent discussions in biofilm conferences and scientific literature. This review consolidates current insights on non-attached aggregates, offering examples of their occurrence in nature and diseases. We discuss their formation and dispersion mechanisms, resilience to antibiotics and immune-responses, drawing parallels to surface-attached biofilms. Moreover, we outline available in vitro models for studying non-attached aggregates.
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Affiliation(s)
- Kasper N Kragh
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Mads Lichtenberg
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
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Perry EK, Tan MW. Bacterial biofilms in the human body: prevalence and impacts on health and disease. Front Cell Infect Microbiol 2023; 13:1237164. [PMID: 37712058 PMCID: PMC10499362 DOI: 10.3389/fcimb.2023.1237164] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 08/11/2023] [Indexed: 09/16/2023] Open
Abstract
Bacterial biofilms can be found in most environments on our planet, and the human body is no exception. Consisting of microbial cells encased in a matrix of extracellular polymers, biofilms enable bacteria to sequester themselves in favorable niches, while also increasing their ability to resist numerous stresses and survive under hostile circumstances. In recent decades, biofilms have increasingly been recognized as a major contributor to the pathogenesis of chronic infections. However, biofilms also occur in or on certain tissues in healthy individuals, and their constituent species are not restricted to canonical pathogens. In this review, we discuss the evidence for where, when, and what types of biofilms occur in the human body, as well as the diverse ways in which they can impact host health under homeostatic and dysbiotic states.
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Affiliation(s)
| | - Man-Wah Tan
- Department of Infectious Diseases, Genentech, South San Francisco, CA, United States
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Khan MM, Ali A, Kolenda R, Olowe OA, Weinreich J, Li G, Schierack P. The role of AJB35136 and fdtA genes in biofilm formation by avian pathogenic Escherichia coli. BMC Vet Res 2023; 19:126. [PMID: 37596603 PMCID: PMC10436575 DOI: 10.1186/s12917-023-03672-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 07/22/2023] [Indexed: 08/20/2023] Open
Abstract
BACKGROUND Infections caused by avian pathogenic Escherichia coli (APEC) result in significant economic losses in poultry industry. APEC strains are known to form biofilms in various conditions allowing them to thrive even under harsh and nutrient-deficient conditions on different surfaces, and this ability enables them to evade chemical and biological eradication methods. Despite knowing the whole genome sequences of various APEC isolates, little has been reported regarding their biofilm-associated genes. A random transposon mutant library of the wild-type APEC IMT 5155 comprising 1,300 mutants was analyzed for biofilm formation under nutrient deprived conditions using Videoscan technology coupled with fluorescence microscopy. Seven transposon mutants were found to have reproducibly and significantly altered biofilm formation and their mutated genes were identified by arbitrary PCR and DNA sequencing. The intact genes were acquired from the wild-type strain, cloned in pACYC177 plasmid and transformed into the respective altered biofilm forming transposon mutants, and the biofilm formation was checked in comparison to the wild type and mutant strains under the same conditions. RESULTS In this study, we report seven genes i.e., nhaA, fdeC, yjhB, lysU, ecpR, AJB35136 and fdtA of APEC with significant contribution to biofilm formation. Reintroduction of AJB35136 and fdtA, reversed the altered phenotype proving that a significant role being played by these two O-antigen related genes in APEC biofilm formation. Presence of these seven genes across nonpathogenic E. coli and APEC genomes was also analyzed showing that they are more prevalent in the latter. CONCLUSIONS The study has elucidated the role of these genes in APEC biofilm formation and compared them to adhesion expanding the knowledge and understanding of the economically significant pathogens.
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Affiliation(s)
- Muhammad Moman Khan
- Institute of Biotechnology, Brandenburg University of Technology, Cottbus-Senftenberg, Universitätsplatz 1, D-01968, Senftenberg, Germany
| | - Aamir Ali
- Institute of Biotechnology, Brandenburg University of Technology, Cottbus-Senftenberg, Universitätsplatz 1, D-01968, Senftenberg, Germany.
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS) , Jhang Road, POBox 577, Faisalabad, Pakistan.
| | - Rafał Kolenda
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
- Quadram Institute, Norwich Research Park, Norwich, UK
| | - Olugbenga Adekunle Olowe
- Institute of Biotechnology, Brandenburg University of Technology, Cottbus-Senftenberg, Universitätsplatz 1, D-01968, Senftenberg, Germany
- Department of Medical Microbiology and Parasitology, College of Health Sciences, Ladoke Akintola University of Technology, Ogbomosho, Oyo State, Nigeria
| | - Jörg Weinreich
- Institute of Biotechnology, Brandenburg University of Technology, Cottbus-Senftenberg, Universitätsplatz 1, D-01968, Senftenberg, Germany
| | - Ganwu Li
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, USA
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Peter Schierack
- Institute of Biotechnology, Brandenburg University of Technology, Cottbus-Senftenberg, Universitätsplatz 1, D-01968, Senftenberg, Germany
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Dhingra S, Vir D, Bakshi J, Rishi P. Mapping of audiometric analysis with microbiological findings in patients with chronic suppurative otitis media (CSOM): a neglected clinical manifestation. Crit Rev Clin Lab Sci 2023; 60:212-232. [PMID: 36604829 DOI: 10.1080/10408363.2022.2158173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Otitis media (OM) is an umbrella term for a number of conditions associated with middle ear inflammation. Chronic suppurative otitis media (CSOM), a type of OM, is characterized by long-term middle ear infection with perforated ear drum and otorrhea. The most common outcome associated with it is acquired hearing impairment in infected individuals which ultimately affects their cognitive and scholastic developments. Clinically, CSOM is thought to be a sequel of re-occurring episodes of Acute otitis media (AOM). Pseudomonas aeruginosa and Staphylococcus aureus are found to be the predominant pathogenic isolates in these patients. However, with the emergence of antibiotic resistance amongst these pathogens, the adequate evaluation and treatment of this condition has become more problematic. The disease has also been recognized as one of the neglected tropical clinical manifestations with high prevalence in school-age children, especially in poor or underprivileged countries. Moreover, untreated cases have further worsened the situation by contributing to various life-threatening complications. Thus, effective treatment and surgical strategies, as well as strengthening of hearing care algorithms along with the discovery of novel animal models for advanced clinical research, can jointly help to fight this disease. In this regard, mapping of the audiological analysis with microbiological findings in CSOM patients may help elucidate the frequency that favors growth of specific pathogens. Knowledge about this potential correlation can then support timely detection of the infection, which is perceived as one of the emerging approaches for its management. In addition to these strategies, creating a true sense of awareness among people can also help mitigate this pathological condition by facilitating early identification, prevention, and treatment. This review discusses the incidence, pathogenesis, investigations, complications, and available treatment modalities associated with CSOM.
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Affiliation(s)
- Shefali Dhingra
- Department of Microbiology, BMS Block I, South Campus, Panjab University, Chandigarh, India
| | - Dharam Vir
- Division of Speech and Hearing, Department of Otolarynology & Head & Neck Surgery, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Jaimanti Bakshi
- Division of Speech and Hearing, Department of Otolarynology & Head & Neck Surgery, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Praveen Rishi
- Department of Microbiology, BMS Block I, South Campus, Panjab University, Chandigarh, India
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An Overview of Biofilm Formation-Combating Strategies and Mechanisms of Action of Antibiofilm Agents. LIFE (BASEL, SWITZERLAND) 2022; 12:life12081110. [PMID: 35892912 PMCID: PMC9394423 DOI: 10.3390/life12081110] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 11/19/2022]
Abstract
Biofilm formation on surfaces via microbial colonization causes infections and has become a major health issue globally. The biofilm lifestyle provides resistance to environmental stresses and antimicrobial therapies. Biofilms can cause several chronic conditions, and effective treatment has become a challenge due to increased antimicrobial resistance. Antibiotics available for treating biofilm-associated infections are generally not very effective and require high doses that may cause toxicity in the host. Therefore, it is essential to study and develop efficient anti-biofilm strategies that can significantly reduce the rate of biofilm-associated healthcare problems. In this context, some effective combating strategies with potential anti-biofilm agents, including plant extracts, peptides, enzymes, lantibiotics, chelating agents, biosurfactants, polysaccharides, organic, inorganic, and metal nanoparticles, etc., have been reviewed to overcome biofilm-associated healthcare problems. From their extensive literature survey, it can be concluded that these molecules with considerable structural alterations might be applied to the treatment of biofilm-associated infections, by evaluating their significant delivery to the target site of the host. To design effective anti-biofilm molecules, it must be assured that the minimum inhibitory concentrations of these anti-biofilm compounds can eradicate biofilm-associated infections without causing toxic effects at a significant rate.
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Das P, Ghosh S, Nayak B. Phyto-fabricated Nanoparticles and Their Anti-biofilm Activity: Progress and Current Status. FRONTIERS IN NANOTECHNOLOGY 2021. [DOI: 10.3389/fnano.2021.739286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Biofilm is the self-synthesized, mucus-like extracellular polymeric matrix that acts as a key virulence factor in various pathogenic microorganisms, thereby posing a serious threat to human health. It has been estimated that around 80% of hospital-acquired infections are associated with biofilms which are found to be present on both biotic and abiotic surfaces. Antibiotics, the current mainstream treatment strategy for biofilms are often found to be futile in the eradication of these complex structures, and to date, there is no effective therapeutic strategy established against biofilm infections. In this regard, nanotechnology can provide a potential platform for the alleviation of this problem owing to its unique size-dependent properties. Accordingly, various novel strategies are being developed for the synthesis of different types of nanoparticles. Bio-nanotechnology is a division of nanotechnology which is gaining significant attention due to its ability to synthesize nanoparticles of various compositions and sizes using biotic sources. It utilizes the rich biodiversity of various biological components which are biocompatible for the synthesis of nanoparticles. Additionally, the biogenic nanoparticles are eco-friendly, cost-effective, and relatively less toxic when compared to chemically or physically synthesized alternatives. Biogenic synthesis of nanoparticles is a bottom-top methodology in which the nanoparticles are formed due to the presence of biological components (plant extract and microbial enzymes) which act as stabilizing and reducing agents. These biosynthesized nanoparticles exhibit anti-biofilm activity via various mechanisms such as ROS production, inhibiting quorum sensing, inhibiting EPS production, etc. This review will provide an insight into the application of various biogenic sources for nanoparticle synthesis. Furthermore, we have highlighted the potential of phytosynthesized nanoparticles as a promising antibiofilm agent as well as elucidated their antibacterial and antibiofilm mechanism.
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Parnell-Turner H, Griffin CE, Rosenkrantz WS, Kelly Keating M, Bidot WA. Evaluation of the use of paired modified Wright's and periodic acid Schiff stains to identify microbial aggregates on cytological smears of dogs with microbial otitis externa and suspected biofilm. Vet Dermatol 2021; 32:448-e122. [PMID: 34351013 DOI: 10.1111/vde.13009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/10/2021] [Accepted: 06/03/2021] [Indexed: 12/31/2022]
Abstract
BACKGROUND Micro-organisms associated with canine otitis externa (OE) may cause biofilm-associated infections (BAI). A key component of biofilm is microbial aggregate and extracellular polymeric substance (EPS). Periodic acid Schiff (PAS) can stain polysaccharide EPS in human otitis media with effusion, but this has not been tested in canine OE. There is no cytological definition for microbial aggregate, and definitive methods for identifying BAI in a clinical setting in canine OE have not been defined. OBJECTIVES To establish whether PAS stain can identify polysaccharide matrix on cytological smears; and to determine the reproducibility of identification of microbial aggregates within a discrete area of stained matrix, using paired modified Wright's and PAS-stained smears. ANIMALS Forty privately-owned dogs presenting to a dermatological referral practice. METHODS AND MATERIALS In this prospective, cross-sectional study, three investigators independently and blindly classified 40 paired modified Wright's-PAS slide sets into groups: aggregate-associated infection (AAI) and non-AAI (n = 27); and control (n = 13). Agreement between investigators for presence of AAI was measured using Fleiss' kappa statistic (FK). Agreement between investigators and dermatologists for presence of AAI upon cytological evaluation, and suspected BAI based on clinical examination, was measured using Cohen's kappa statistic. RESULTS The matrix was confirmed to stain PAS-positive. Interinvestigator agreement for AAI was very good using PAS (0.82 FK) and fair using modified-Wright's (MW) (0.33 FK). Reproducible cytological features associated with AAI were the presence of: three or more distinct aggregates (0.76 FK); discrete areas of PAS-positive matrix (0.70 FK); and the presence of high-density material (0.70 FK) using PAS stain. CONCLUSION PAS can stain the extracellular matrix on otic smears, and a novel protocol for reproducible identification of cytological features such as microbial aggregates has been established.
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Affiliation(s)
| | - Craig E Griffin
- Animal Dermatology Clinic, 5610 Kearny Mesa Road, San Diego, CA, 92111, USA
| | | | - M Kelly Keating
- Animal Dermatology Clinic, 2965 Edinger Avenue, Tustin, CA, 92780, USA
| | - Willie A Bidot
- Office of Animal Resources, Western University of Health Sciences, Pomona, CA, 91766, USA
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Locke A, Fitzgerald S, Mahadevan-Jansen A. Advances in Optical Detection of Human-Associated Pathogenic Bacteria. Molecules 2020; 25:E5256. [PMID: 33187331 PMCID: PMC7696695 DOI: 10.3390/molecules25225256] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 02/06/2023] Open
Abstract
Bacterial infection is a global burden that results in numerous hospital visits and deaths annually. The rise of multi-drug resistant bacteria has dramatically increased this burden. Therefore, there is a clinical need to detect and identify bacteria rapidly and accurately in their native state or a culture-free environment. Current diagnostic techniques lack speed and effectiveness in detecting bacteria that are culture-negative, as well as options for in vivo detection. The optical detection of bacteria offers the potential to overcome these obstacles by providing various platforms that can detect bacteria rapidly, with minimum sample preparation, and, in some cases, culture-free directly from patient fluids or even in vivo. These modalities include infrared, Raman, and fluorescence spectroscopy, along with optical coherence tomography, interference, polarization, and laser speckle. However, these techniques are not without their own set of limitations. This review summarizes the strengths and weaknesses of utilizing each of these optical tools for rapid bacteria detection and identification.
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Affiliation(s)
- Andrea Locke
- Vanderbilt Biophotonics Center, Nashville, TN 37232, USA; (A.L.); (S.F.)
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Sean Fitzgerald
- Vanderbilt Biophotonics Center, Nashville, TN 37232, USA; (A.L.); (S.F.)
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Anita Mahadevan-Jansen
- Vanderbilt Biophotonics Center, Nashville, TN 37232, USA; (A.L.); (S.F.)
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
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Nogues JC, Pérez‐Losada M, Preciado D. Review of otitis media microbiome studies: What do they tell us? Laryngoscope Investig Otolaryngol 2020; 5:936-940. [PMID: 33134542 PMCID: PMC7585249 DOI: 10.1002/lio2.460] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/02/2020] [Accepted: 09/04/2020] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVES To provide a state of the art review on accruing studies focused on defining the middle ear microbiome, highlighting the relationship of the microbiome to disease pathophysiology. DATA SOURCES Pubmed indexed peer-reviewed articles and published textbooks. REVIEW METHODS Comprehensive review of the literature using the following search terms: "microbiome" "bacterial pathogens" with the term "otitis media," and "middle ear." RESULTS A multitude of microbiome studies have been published in the recent past. In general findings from these studies underscore distinct profiles based on disease category. The adenoidal reservoir theory may not explain all etiologies of middle ear effusion production. The host immune system appears to be associated to the bacterial population identified in the middle ear space. Atopic respiratory diseases correlate to the middle ear microbiome. Some novel middle ear bacterial genera may be protective in terms of disease. CONCLUSION The understanding of otitis media disease progression pathophysiology is evolving, informed by accruing middle ear microbiomic data. The functional implications of middle ear microbiome findings need to be studied further. This may help counterbalance probiotic vs antibiotic approaches to disease mitigation.
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Affiliation(s)
- Juan Carlos Nogues
- Division of Pediatric OtolaryngologyHead and Neck Surgery, Children's National Health SystemWashingtonDistrict of ColumbiaUSA
| | - Marcos Pérez‐Losada
- CIBIO‐InBIO, Centro de Investigação em Biodiversidade e Recursos GenéticosUniversidade do Porto, Campus Agrário de VairãoVairãoPortugal
- Computational Biology Institute, Department of Biostatistics and BioinformaticsMilken Institute School of Public Health, George Washington UniversityWashingtonDistrict of ColumbiaUSA
| | - Diego Preciado
- Division of Pediatric OtolaryngologyHead and Neck Surgery, Children's National Health SystemWashingtonDistrict of ColumbiaUSA
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Elzayat S, Nosair N, Ghazy AA, Abdulghaffar IA. Otitis media with effusion is not a sterile inflammatory process: scanning electron microscope evidence. Eur Arch Otorhinolaryngol 2020; 278:2713-2721. [PMID: 32889624 DOI: 10.1007/s00405-020-06338-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 08/28/2020] [Indexed: 11/28/2022]
Abstract
PURPOSE We aimed to demonstrate whether chronic otitis media with effusion (OME) is a sterile condition or biofilms-related disease through direct visualization of middle ear mucosa by Scanning electron microscopy (SEM) and culture of the effusion. METHODS This case-control study included 60 children in two groups; the case group included 50 patients undergoing ventilation tube insertion (VTI) for Chronic OME (COME), and the control group included ten patients undergoing cochlear implantation (CI) surgery presenting normal middle ear mucosa. Biopsies from both groups' middle ear mucosa were evaluated for biofilm formation using scanning electron microscopy (SEM). Middle ear effusion (MEE) samples from COME patients were cultured on blood agar to detect and identify any bacterial growth. The adenoid size was evaluated and correlated to the biofilm formation in COME patients. RESULTS There was a significant difference between case and control groups regarding biofilm formation (p-value < 0.001*). Biofilm was evident in 84% of the COME patients (cases group) and absent in the control group. Only 12 COME patients (24%) had positive MEE culture, however, 76.2% of patients with biofilm had a negative culture. Streptococcus pneumonia was the most common otopathogen found either alone or combined with other otopathogens. There was a significant negative correlation between adenoid size and biofilm grade among the studied patients. CONCLUSION The visual identification of middle ear biofilms indicated their role in chronic OME. Middle ear biofilms need to be expected in children with OME, especially those who do not need adenoid surgery.
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Affiliation(s)
- Saad Elzayat
- Otorhinolaryngology, Faculty of Medicine, Kafrelsheikh University, El-geish street, Kafrelsheikh, 33155, Egypt
| | - Nahla Nosair
- Clinical Pathology, Faculty of Medicine, Kafrelsheikh University, Kafrelsheikh, Egypt
| | - Amany A Ghazy
- Pathology (Microbiology & Immunology Unit), College of Medicine, Jouf University, Sakaka, Saudi Arabia.,Microbiology and Immunology, Faculty of Medicine, Kafrelsheikh University, Kafrelsheikh, Egypt
| | - Ibrahim A Abdulghaffar
- Otorhinolaryngology, Faculty of Medicine, Kafrelsheikh University, El-geish street, Kafrelsheikh, 33155, Egypt.
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Domnin P, Arkhipova A, Petrov S, Sysolyatina E, Parfenov V, Karalkin P, Mukhachev A, Gusarov A, Moisenovich M, Khesuani Y, Ermolaeva S. An In Vitro Model of Nonattached Biofilm-Like Bacterial Aggregates Based on Magnetic Levitation. Appl Environ Microbiol 2020; 86:e01074-20. [PMID: 32680859 PMCID: PMC7480373 DOI: 10.1128/aem.01074-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/10/2020] [Indexed: 12/27/2022] Open
Abstract
Chronic infections are associated with the formation of nonattached biofilm-like aggregates. In vitro models of surface-attached biofilms do not always accurately mimic these processes. Here, we tested a new approach to create in vitro nonattached bacterial aggregates using the principle of magnetic levitation of biological objects placed into a magnetic field gradient. Bacteria grown under magnetic levitation conditions formed nonattached aggregates that were studied with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) and characterized quantitatively. Nonattached aggregates consisted of bacteria submerged into an extracellular matrix and demonstrated features characteristic of biofilms, such as a polymeric matrix that binds Ruby Red and Congo red dyes, a prerequisite of bacterial growth, and increased resistance to gentamicin. Three quantitative parameters were explored to characterize strain-specific potential to form nonattached aggregates: geometric sizes, relative quantities of aggregated and free-swimming bacteria, and Congo red binding. Among three tested Escherichia coli strains, one strain formed nonattached aggregates poorly, and for this strain, all three of the considered parameters were different from those of the other two strains (P < 0.05). Further, we characterized biofilm formation on plastic and agar surfaces by these strains and found that good biofilm formation ability does not necessarily indicate good nonattached aggregate formation ability, and vice versa. The model and quantitative methods can be applied for in vitro studies of nonattached aggregates and modeling bacterial behavior in chronic infections, as it is important to increase our understanding of the role that nonattached bacterial aggregates play in the pathogenesis of chronic diseases.IMPORTANCE An increasing amount of evidence indicates that chronic infections are associated with nonattached biofilm-like aggregates formed by pathogenic bacteria. These aggregates differ from biofilms because they form under low-shear conditions within the volume of biological fluids and they do not attach to surfaces. Here, we describe an in vitro model that provides nonattached aggregate formation within the liquid volume due to magnetic levitation. Using this model, we demonstrated that despite morphological and functional similarities of nonattached aggregates and biofilms, strains that exhibit good biofilm formation might exhibit poor nonattached aggregate formation, suggesting that mechanisms underlying the formation of biofilms and nonattached aggregates are not identical. The magnetic levitation approach can be useful for in vitro studies of nonattached aggregate formation and simulation of bacterial behavior in chronic infections.
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Affiliation(s)
- Pavel Domnin
- Gamaleya Research Centre of Epidemiology and Microbiology, Moscow, Russia
- Lomonosov Moscow State University, Moscow, Russia
| | | | | | - Elena Sysolyatina
- Gamaleya Research Centre of Epidemiology and Microbiology, Moscow, Russia
| | | | | | - Andrey Mukhachev
- Gamaleya Research Centre of Epidemiology and Microbiology, Moscow, Russia
| | - Alexey Gusarov
- Gamaleya Research Centre of Epidemiology and Microbiology, Moscow, Russia
| | | | | | - Svetlana Ermolaeva
- Gamaleya Research Centre of Epidemiology and Microbiology, Moscow, Russia
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15
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Kvich L, Burmølle M, Bjarnsholt T, Lichtenberg M. Do Mixed-Species Biofilms Dominate in Chronic Infections?-Need for in situ Visualization of Bacterial Organization. Front Cell Infect Microbiol 2020; 10:396. [PMID: 32850494 PMCID: PMC7419433 DOI: 10.3389/fcimb.2020.00396] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 06/29/2020] [Indexed: 12/19/2022] Open
Abstract
Chronic infections present a serious economic burden to health-care systems. The severity and prevalence of chronic infections are continuously increasing due to an aging population and an elevated number of lifestyle related diseases such as diabetes. Treatment of chronic infections has proven difficult, mainly due to the presence of biofilms that render bacteria more tolerant toward antimicrobials and the host immune response. Chronic infections have been described to harbor several different bacterial species and it has been hypothesized that microscale interactions and mixed-species consortia are present as described for most natural occurring biofilms i.e., aquatic systems and industrial settings, but also for some commensal human biofilms i.e., the mouth microbiota. However, the presence of mixed-species biofilms in chronic infections is most often an assumption based on culture-based methods and/or by means of molecular approaches, such as PCR and sequencing performed from homogenized bulk tissue samples. These methods disregard the spatial organization of the bacterial community and thus valuable information on biofilm aggregate composition, spatial organization, and possible interactions between different species is lost. Hitherto, only few studies have made visual in situ presentations of mixed-species biofilms in chronic infections, which is pivotal for the description of bacterial composition, spatial distribution, and interspecies interaction on the microscale. In order for bacteria to interact (synergism, commensalism, mutualism, competition, etc.) they need to be in close proximity to each other on the scale where they can affect e.g., solute concentrations. We argue that visual proof of mixed species biofilms in chronic infections is scarce compared to what is seen in e.g., environmental biofilms and call for a debate on the importance of mixed-species biofilm in chronic infections.
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Affiliation(s)
- Lasse Kvich
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Mette Burmølle
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Mads Lichtenberg
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
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16
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Mirzaei R, Mohammadzadeh R, Sholeh M, Karampoor S, Abdi M, Dogan E, Moghadam MS, Kazemi S, Jalalifar S, Dalir A, Yousefimashouf R, Mirzaei E, Khodavirdipour A, Alikhani MY. The importance of intracellular bacterial biofilm in infectious diseases. Microb Pathog 2020; 147:104393. [PMID: 32711113 DOI: 10.1016/j.micpath.2020.104393] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 12/17/2022]
Abstract
Various bacterial species, previously known as extracellular pathogens, can reside inside different host cells by adapting to intracellular modes by forming microbial aggregates with similar characteristics to bacterial biofilms. Additionally, bacterial invasion of human cells leads to failure in antibiotic therapy, as most conventional anti-bacterial agents cannot reach intracellular biofilm in normal concentrations. Various studies have shown that bacteria such as uropathogenic Escherichia coli, Pseudomonas aeruginosa, Borrelia burgdorferi,Moraxella catarrhalis, non-typeable Haemophilus influenzae, Streptococcus pneumonia, and group A Streptococci produce biofilm-like structures within the host cells. For the first time in this review, we will describe and discuss the new information about intracellular bacterial biofilm formation and its importance in bacterial infectious diseases.
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Affiliation(s)
- Rasoul Mirzaei
- Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran; Student Research Committee, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Rokhsareh Mohammadzadeh
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Sholeh
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Sajad Karampoor
- Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Milad Abdi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Student Research Committee, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Eyup Dogan
- Department of Basic Biotechnology, Biotechnology Institute, Ankara, Turkey
| | - Mohammad Shokri Moghadam
- Department of Microbiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Sima Kazemi
- Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Saba Jalalifar
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Amine Dalir
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Rasoul Yousefimashouf
- Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Ebrahim Mirzaei
- Department of Medical Genetics and Molecular Biology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Amir Khodavirdipour
- Division of Humann Genetics, Department of Anatomy, St. John's Hospital, Bangalore, India
| | - Mohammad Yousef Alikhani
- Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
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17
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Bidossi A, Bottagisio M, Savadori P, De Vecchi E. Identification and Characterization of Planktonic Biofilm-Like Aggregates in Infected Synovial Fluids From Joint Infections. Front Microbiol 2020; 11:1368. [PMID: 32714301 PMCID: PMC7344156 DOI: 10.3389/fmicb.2020.01368] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 05/27/2020] [Indexed: 01/10/2023] Open
Abstract
Recent in vitro studies reported the exceptional ability of some bacterial species to form biofilm-like aggregates in human and animal synovial fluids (SF), but evidences from infected clinical samples are still lacking. In this study, we investigated whether this bacterial phenotype was present in infected SFs collected from joint infections and if it was maintained in in vitro settings. SFs sent for culture to the Laboratory of Microbiology of our institute were directly analyzed by means of confocal laser scanning microscopy (CLSM), and the infective agents were isolated for further in vitro tests. Moreover, sterile SF was collected from patients who did not receive previous antibiotic therapy to investigate the formation of bacterial aggregates, together with biofilm and matrix production on a titanium surface. Finally, antibiotic susceptibility studies were performed by using bovine SF. Four Staphylococcus aureus, one Staphylococcus lugdunensis, and one Prevotella bivia strain were identified in the infected SFs. The CLSM analysis showed that all staphylococci were present as a mixture of single cells and bacterial clumps surrounded by an exopolymeric substance, which comprised SF-derived fibrin, while all P. bivia cells appeared separated. Despite that, differences in the ability to aggregate between S. aureus and S. lugdunensis were observed in clinical SFs. These different phenotypes were further confirmed by in vitro growth, even though the application of such ex vivo approach lead all staphylococci to form exceptionally large microbial aggregates, which are several folds bigger than those observed in clinical samples. Planktonic aggregates challenged for antibiotic susceptibility revealed a sharp increase of recalcitrance to the treatments. Although this is still at a preliminary stage, the present work confirmed the ability of staphylococci to form free-floating biofilm-like aggregates in infected SF from patients with joint infections. Furthermore, the obtained results pointed out that future in vitro research on joint infections will benefit from the use of human- or animal-derived SF. Even though this approach should be carefully validated in further studies comprising a larger microbial population, these findings pose new challenges in the treatment of infected native and prosthetic joints and for the approach to new investigations.
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Affiliation(s)
- Alessandro Bidossi
- Laboratory of Clinical Chemistry and Microbiology, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Marta Bottagisio
- Laboratory of Clinical Chemistry and Microbiology, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Paolo Savadori
- Department of Endodontics, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Elena De Vecchi
- Laboratory of Clinical Chemistry and Microbiology, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
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18
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Kjeldsen M, Homøe P, Kirstine Nielsen A, Crone S, Nørskov Kragh K, Bjarnsholt T. Eradication of biofilms on tympanostomy tubes with acetic acid treatment: an in vitro study. APMIS 2020; 128:445-450. [PMID: 32277844 DOI: 10.1111/apm.13044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/01/2020] [Indexed: 11/26/2022]
Abstract
The purpose was to evaluate the eradicative effect of acetic acid on bacterial biofilm grown on tympanostomy tubes by an in vitro experiment. Biofilms of Pseudomonas aeruginosa and Staphylococcus aureus were grown on sterile tympanostomy tubes for 24 h. The tubes were treated with acetic acid solutions at various concentrations for 24 h. Main outcome was viability of bacteria after treatment. The presence of consistently attached biofilm was examined on selected tympanostomy tubes with confocal laser scanning microscopy. Both pH-adjusted and non-pH-adjusted media solutions were applied as control groups. Results showed complete eradication of P. aeruginosa biofilm with 0.50% v/v acetic acid. Biofilm of S. aureus was eradicated with 1.25% v/v acetic acid. Low pH value alone led to decreased growth of already established biofilm, but not eradication. In conlusion, acetic acid showed an eradicating effect on biofilm established on sterile tympanostomy tubes in vitro.
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Affiliation(s)
- Mathilde Kjeldsen
- Costerton Biofilm Center, University of Copenhagen, Copenhagen N, Denmark.,Department of Otorhinolaryngology and Maxillofacial Surgery, Zealand University Hospital, Køge, Denmark
| | - Preben Homøe
- Department of Otorhinolaryngology and Maxillofacial Surgery, Zealand University Hospital, Køge, Denmark.,Institute of Clinical Medicine, University of Copenhagen, Copenhagen N, Denmark
| | | | - Stephanie Crone
- Costerton Biofilm Center, University of Copenhagen, Copenhagen N, Denmark
| | - Kasper Nørskov Kragh
- Costerton Biofilm Center, University of Copenhagen, Copenhagen N, Denmark.,Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen Ø, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, University of Copenhagen, Copenhagen N, Denmark.,Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen Ø, Denmark
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19
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Prevalence and etiological agents for chronic suppurative otitis media in a tertiary hospital in Tanzania. BMC Res Notes 2019; 12:429. [PMID: 31315659 PMCID: PMC6637475 DOI: 10.1186/s13104-019-4483-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 07/15/2019] [Indexed: 11/10/2022] Open
Abstract
Objective Chronic suppurative otitis media is among the most common otological condition reported in otorhinolaryngology practice commonly attributing to preventable hearing loss. The aim of this study was to determine the prevalence and etiological agents for chronic suppurative otitis media in our department. Results A total of 5591 patients were recruited in this study and only 79 (1.4%) had chronic suppurative otitis media. A male preponderance 43 (54.4%) was noted in this study and the left ear (58.2%) was more commonly affected compared to the right ear. Central perforation was the commonest pattern of presentation and was reported in 53% of cases though none had attic perforation. Of the 81 processed ear swabs, microbial growth was seen in majority 80 (98.8%) whilst one sample showed no microbial growth whereas 52.5% had polymicrobial growth. Among the isolates, most were gram negative species accounting for 59.7% while gram positive bacteria accounted for 25.6% and fungi accounted for 14.7%. Most of these isolates were facultative anaerobes. Klebsiella pneumoniae (20.2%) was the commonest isolates while Escherichia coli and Pseudomonas aeruginosa were equally least isolated (10.9%). Tested isolates were most sensitive to Ciprofloxacin, Gentamycin, Ceftriaxone and Amikacin and least sensitive to Amoxicillin/clavulanic acid and Ampicillin. Electronic supplementary material The online version of this article (10.1186/s13104-019-4483-x) contains supplementary material, which is available to authorized users.
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20
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Motility-Independent Formation of Antibiotic-Tolerant Pseudomonas aeruginosa Aggregates. Appl Environ Microbiol 2019; 85:AEM.00844-19. [PMID: 31076438 DOI: 10.1128/aem.00844-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 05/07/2019] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas aeruginosa is a bacterial pathogen that causes severe chronic infections in immunocompromised individuals. This bacterium is highly adaptable to its environments, which frequently select for traits that promote bacterial persistence. A clinically significant temporal adaptation is the formation of surface- or cell-adhered bacterial biofilms that are associated with increased resistance to immune and antibiotic clearance. Extensive research has shown that bacterial flagellar motility promotes formation of such biofilms, whereupon the bacteria subsequently become nonmotile. However, recent evidence shows that antibiotic-tolerant nonattached bacterial aggregates, distinct from surface-adhered biofilms, can form, and these have been reported in the context of lung infections, otitis media, nonhealing wounds, and soft tissue fillers. It is unclear whether the same bacterial traits are required for aggregate formation as for biofilm formation. In this report, using isogenic mutants, we demonstrate that P. aeruginosa aggregates in liquid cultures are spontaneously formed independent of bacterial flagellar motility and independent of an exogenous scaffold. This contrasts with the role of the flagellum to initiate surface-adhered biofilms. Similarly to surface-attached biofilms, these aggregates exhibit increased antibiotic tolerance compared to planktonic cultures. These findings provide key insights into the requirements for aggregate formation that contrast with those for biofilm formation and that may have relevance for the persistence and dissemination of nonmotile bacteria found within chronic clinical infections.IMPORTANCE In this work, we have investigated the role of bacterial motility with regard to antibiotic-tolerant bacterial aggregate formation. Previous work has convincingly demonstrated that P. aeruginosa flagellar motility promotes the formation of surface-adhered biofilms in many systems. In contrast, aggregate formation by P. aeruginosa was observed for nonmotile but not for motile cells in the presence of an exogenous scaffold. Here, we demonstrate that both wild-type P. aeruginosa and mutants that genetically lack motility spontaneously form antibiotic-tolerant aggregates in the absence of an exogenously added scaffold. Additionally, we also demonstrate that wild-type (WT) and nonmotile P. aeruginosa bacteria can coaggregate, shedding light on potential physiological interactions and heterogeneity of aggregates.
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21
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Torretta S, Drago L, Marchisio P, Ibba T, Pignataro L. Role of Biofilms in Children with Chronic Adenoiditis and Middle Ear Disease. J Clin Med 2019; 8:jcm8050671. [PMID: 31086039 PMCID: PMC6571864 DOI: 10.3390/jcm8050671] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/26/2019] [Accepted: 05/10/2019] [Indexed: 01/31/2023] Open
Abstract
Chronic adenoiditis occurs frequently in children, and it is complicated by the subsequent development of recurrent or chronic middle ear diseases, such as recurrent acute otitis media, persistent otitis media with effusion and chronic otitis media, which may predispose a child to long-term functional sequalae and auditory impairment. Children with chronic adenoidal disease who fail to respond to traditional antibiotic therapy are usually candidates for surgery under general anaesthesia. It has been suggested that the ineffectiveness of antibiotic therapy in children with chronic adenoiditis is partially related to nasopharyngeal bacterial biofilms, which play a role in the development of chronic nasopharyngeal inflammation due to chronic adenoiditis, which is possibly associated with chronic or recurrent middle ear disease. This paper reviews the current evidence concerning the involvement of bacterial biofilms in the development of chronic adenoiditis and related middle ear infections in children.
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Affiliation(s)
- Sara Torretta
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Policlinico of Milan, Via Francesco Sforza, 35, 20122 Milano, Italy.
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy.
| | - Lorenzo Drago
- Clinical Chemistry and Microbiology Laboratory, IRCCS Galeazzi Institute and LITA Clinical Microbiology Laboratory, 20161 Milano, Italy.
- Department of Clinical Science, University of Milan, 20122 Milan, Italy.
| | - Paola Marchisio
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Policlinico of Milan, Via Francesco Sforza, 35, 20122 Milano, Italy.
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy.
| | - Tullio Ibba
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Policlinico of Milan, Via Francesco Sforza, 35, 20122 Milano, Italy.
| | - Lorenzo Pignataro
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Policlinico of Milan, Via Francesco Sforza, 35, 20122 Milano, Italy.
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy.
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22
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Coleman A, Wood A, Bialasiewicz S, Ware RS, Marsh RL, Cervin A. The unsolved problem of otitis media in indigenous populations: a systematic review of upper respiratory and middle ear microbiology in indigenous children with otitis media. MICROBIOME 2018; 6:199. [PMID: 30396360 PMCID: PMC6219068 DOI: 10.1186/s40168-018-0577-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/15/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Otitis media (OM) imposes a great burden of disease in indigenous populations around the world, despite a variety of treatment and prevention programs. Improved understanding of the pathogenesis of OM in indigenous populations is required to advance treatment and reduce prevalence. We conducted a systematic review of the literature exploring the upper airway and middle ear microbiota in relation to OM in indigenous children. METHODS Papers targeting microbiota in relation to OM in children < 18 years indigenous to Australia, New Zealand, North America, and Greenland were sought. MEDLINE, CINAHL, EMBASE, Cochrane Library, and Informit databases were searched using key words. Two independent reviewers screened titles, abstracts, and then full-text papers against inclusion criteria according to PRISMA guidelines. RESULTS Twenty-five papers considering indigenous Australian, Alaskan, and Greenlandic children were included. There were high rates of nasopharyngeal colonization with the three main otopathogens (Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis) in indigenous children with OM. Middle ear samples had lower rates of otopathogen detection, although detection rates increased when molecular methods were used. Pseudomonas aeruginosa and Staphylococcus aureus were commonly detected in middle ear discharge of children with chronic suppurative OM. There was a significant heterogeneity between studies, particularly in microbiological methods, which were largely limited to culture-based detection of the main otopathogens. CONCLUSIONS There are high rates of otopathogen colonization in indigenous children with OM. Chronic suppurative OM appears to be associated with a different microbial profile. Beyond the main otopathogens, the data are limited. Further research is required to explore the entire upper respiratory tract/middle ear microbiota in relation to OM, with the inclusion of healthy indigenous peers as controls.
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Affiliation(s)
- Andrea Coleman
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland Australia
- Queensland Pediatric Infectious Disease Laboratory, Centre for Children’s Health Research, Children’s Health Queensland Hospital, Queensland University of Technology, Child Health Research Centre, The University of Queensland, 62 Graham Street, South Brisbane, Queensland 4101 Australia
| | - Amanda Wood
- The Deadly Ears Program, Children’s Health Queensland Hospital and Health Service, Brisbane, Queensland Australia
| | - Seweryn Bialasiewicz
- Queensland Pediatric Infectious Disease Laboratory, Centre for Children’s Health Research, Children’s Health Queensland Hospital, Queensland University of Technology, Child Health Research Centre, The University of Queensland, 62 Graham Street, South Brisbane, Queensland 4101 Australia
| | - Robert S. Ware
- Menzies Health Institute Queensland, Griffith University, Brisbane, Queensland Australia
| | - Robyn L. Marsh
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory Australia
| | - Anders Cervin
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland Australia
- Head & Neck Surgery, Department of Otolaryngology, Royal Brisbane and Women’s Hospital, Brisbane, Queensland Australia
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Roy R, Tiwari M, Donelli G, Tiwari V. Strategies for combating bacterial biofilms: A focus on anti-biofilm agents and their mechanisms of action. Virulence 2018; 9:522-554. [PMID: 28362216 PMCID: PMC5955472 DOI: 10.1080/21505594.2017.1313372] [Citation(s) in RCA: 687] [Impact Index Per Article: 114.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. The biofilm matrix surrounding bacteria makes them tolerant to harsh conditions and resistant to antibacterial treatments. Moreover, the biofilms are responsible for causing a broad range of chronic diseases and due to the emergence of antibiotic resistance in bacteria it has really become difficult to treat them with efficacy. Furthermore, the antibiotics available till date are ineffective for treating these biofilm related infections due to their higher values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which may result in in-vivo toxicity. Hence, it is critically important to design or screen anti-biofilm molecules that can effectively minimize and eradicate biofilm related infections. In the present article, we have highlighted the mechanism of biofilm formation with reference to different models and various methods used for biofilm detection. A major focus has been put on various anti-biofilm molecules discovered or tested till date which may include herbal active compounds, chelating agents, peptide antibiotics, lantibiotics and synthetic chemical compounds along with their structures, mechanism of action and their respective MICs, MBCs, minimum biofilm inhibitory concentrations (MBICs) as well as the half maximal inhibitory concentration (IC50) values available in the literature so far. Different mode of action of anti biofilm molecules addressed here are inhibition via interference in the quorum sensing pathways, adhesion mechanism, disruption of extracellular DNA, protein, lipopolysaccharides, exopolysaccharides and secondary messengers involved in various signaling pathways. From this study, we conclude that the molecules considered here might be used to treat biofilm-associated infections after significant structural modifications, thereby investigating its effective delivery in the host. It should also be ensured that minimum effective concentration of these molecules must be capable of eradicating biofilm infections with maximum potency without posing any adverse side effects on the host.
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Affiliation(s)
- Ranita Roy
- a Department of Biochemistry , Central University of Rajasthan , Ajmer , India
| | - Monalisa Tiwari
- a Department of Biochemistry , Central University of Rajasthan , Ajmer , India
| | - Gianfranco Donelli
- b Microbial Biofilm Laboratory, IRCCS Fondazione Santa Lucia , Rome , Italy
| | - Vishvanath Tiwari
- a Department of Biochemistry , Central University of Rajasthan , Ajmer , India
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Alhede M, Stavnsbjerg C, Bjarnsholt T. The use of fluorescent staining techniques for microscopic investigation of polymorphonuclear leukocytes and bacteria. APMIS 2018; 126:779-794. [DOI: 10.1111/apm.12888] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/14/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Maria Alhede
- Costerton Biofilm Center; Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Camilla Stavnsbjerg
- Costerton Biofilm Center; Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center; Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
- Department of Immunology and Microbiology; Rigshospitalet; Copenhagen Denmark
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25
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Bhutta MF, Thornton RB, Kirkham LAS, Kerschner JE, Cheeseman MT. Understanding the aetiology and resolution of chronic otitis media from animal and human studies. Dis Model Mech 2018; 10:1289-1300. [PMID: 29125825 PMCID: PMC5719252 DOI: 10.1242/dmm.029983] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Inflammation of the middle ear, known clinically as chronic otitis media, presents in different forms, such as chronic otitis media with effusion (COME; glue ear) and chronic suppurative otitis media (CSOM). These are highly prevalent diseases, especially in childhood, and lead to significant morbidity worldwide. However, much remains unclear about this disease, including its aetiology, initiation and perpetuation, and the relative roles of mucosal and leukocyte biology, pathogens, and Eustachian tube function. Chronic otitis media is commonly modelled in mice but most existing models only partially mimic human disease and many are syndromic. Nevertheless, these models have provided insights into potential disease mechanisms, and have implicated altered immune signalling, mucociliary function and Eustachian tube function as potential predisposing mechanisms. Clinical studies of chronic otitis media have yet to implicate a particular molecular pathway or mechanism, and current human genetic studies are underpowered. We also do not fully understand how existing interventions, such as tympanic membrane repair, work, nor how chronic otitis media spontaneously resolves. This Clinical Puzzle article describes our current knowledge of chronic otitis media and the existing research models for this condition. It also identifies unanswered questions about its pathogenesis and treatment, with the goal of advancing our understanding of this disease to aid the development of novel therapeutic interventions. Summary: Chronic middle ear inflammation is a common disease. Animal models, and in particular mouse models, have been used to elucidate some potential mechanisms, including dysfunction in immune signalling, mucociliary function or Eustachian tube function.
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Affiliation(s)
- Mahmood F Bhutta
- Department of ENT, Brighton and Sussex University Hospitals NHS Trust, Brighton, BN2 5BE, England .,Division of Paediatrics, University of Western Australia, Subiaco, WA 6008, Australia
| | - Ruth B Thornton
- Division of Paediatrics, University of Western Australia, Subiaco, WA 6008, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Subiaco, WA 6008, Australia
| | - Lea-Ann S Kirkham
- Division of Paediatrics, University of Western Australia, Subiaco, WA 6008, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Subiaco, WA 6008, Australia
| | - Joseph E Kerschner
- Office of the Dean, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Michael T Cheeseman
- Division of Developmental Biology, Roslin Institute, University of Edinburgh, Midlothian, EH23 9RG, Scotland
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Morphological evidence of biofilm in chronic obstructive sialadenitis. The Journal of Laryngology & Otology 2018; 132:611-614. [PMID: 29986787 DOI: 10.1017/s0022215118000646] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Bacterial infection is a common finding in acute sialadenitis and may play a role in the chronicity of the condition. This study investigated if bacterial biofilm is present in submandibular chronic obstructive sialadenitis. METHODS A descriptive case-control study was conducted that compared 10 histological sections of submandibular glands with chronic obstructive sialadenitis, to 10 histological sections of the healthy part of submandibular glands with pleomorphic adenoma. Fluorescence in situ hybridisation and confocal laser scanning microscopy visualised evidence of bacterial biofilm. RESULTS In the chronic obstructive sialadenitis group, 5 out of 10 histological sections showed morphological evidence of bacterial biofilm. In the control group, there was no sign of bacterial biofilm formation. CONCLUSION Morphological evidence of bacterial biofilm was found in the submandibular gland sections from patients with chronic sialadenitis and suggests a role in the chronicity of submandibular chronic obstructive sialadenitis.
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Antibacterial and Antibiofilm Activities of Cinnamomum Sp. Essential Oil and Cinnamaldehyde: Antimicrobial Activities. ScientificWorldJournal 2018; 2018:7405736. [PMID: 29977171 PMCID: PMC6011056 DOI: 10.1155/2018/7405736] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/12/2018] [Indexed: 02/06/2023] Open
Abstract
To assess the activities of essential oils derived from the trunk bark of Cinnamomum zeylanicum (EOCz) and Cinnamomum cassia (EOCc) as well as cinnamaldehyde on bacterial biofilms of clinical interest. Antimicrobial activity was assessed by the broth microdilution method to determine minimum inhibitory concentrations (MICs). Antibiofilm activity was assessed by quantifying the biomass and determining the number of viable cells. The chemical composition of the essential oils was determined. The results showed that the major component of EOCz and EOCc was cinnamaldehyde. For the assayed substances, biofilm biomasses were reduced by up to 99.9%, and Streptococcus pyogenes, Pseudomonas aeruginosa, and Escherichia coli biofilms were sensitive to all of the concentrations and substances analysed. In cell viability tests, 2 mg/ml of cinnamaldehyde reduced the number of viable cells by 5.74 Log CFU/ml. EOCz, EOCc, and cinnamaldehyde exhibited antimicrobial and antibiofilm activities. This work describes substances with potential use against infections caused by bacterial biofilms.
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Abi Hachem R, Goncalves S, Walker T, Angeli S. Middle ear irrigation using a hydrodebrider decreases biofilm surface area in an animal model of otitis media. Laryngoscope Investig Otolaryngol 2018; 3:231-237. [PMID: 30062140 PMCID: PMC6057225 DOI: 10.1002/lio2.164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 03/15/2018] [Accepted: 03/30/2018] [Indexed: 11/16/2022] Open
Abstract
Objective To compare the safety and efficacy of manual and powered irrigation of the middle ear using saline or 1% baby shampoo to treat biofilm‐forming bacterial middle ear infections. Background Biofilms play a major role in recalcitrant otitis media and are challenging to treat. Many therapeutic strategies have been attempted and the role of topical therapies is still being investigated. Topical irrigation using saline or 1% baby shampoo and the use of a hydrodebrider have been investigated in biofilms involved in chronic rhinosinusitis and their role within the middle ear is yet to be determined. Methods Twenty‐two adult chinchillas underwent bilateral trans‐bullar inoculation of non‐typable biofilm forming Haemophilus influenza followed by unilateral middle ear irrigation 5 days later using saline administered via a powered hydrodebrider or manual irrigation of saline or 1% baby shampoo. Contralateral inoculated ears served as control and were not irrigated. Two days following irrigation, the bullae were harvested and processed for scanning electron microscopy to assess biofilm surface area. Auditory brainstem responses were performed before bacterial inoculation and prior to euthanasia. Results Manual and powered irrigation were effective in reducing the surface area of biofilm when compared to the control group. The hydrodebrider demonstrated to be more effective at eradicating biofilm than manual irrigation, especially in areas of difficult access, such as the ventral portion of the chinchillas' bullae. There was no difference in manual irrigation of saline when compared to 1% baby shampoo. Irrigations either manually or using the hydrodebrider did not affect hearing, the vestibular system or facial function. Conclusion Middle ear biofilms can be treated safely and effectively with rinses using either normal saline or 1% baby shampoo administered manually or with a powered hydrodebrider. Level of Evidence NA.
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Affiliation(s)
- Ralph Abi Hachem
- Department of Otolaryngology-Head and Neck Surgery University of Miami Miller School of Medicine Miami Florida U.S.A
| | - Stefania Goncalves
- Department of Otolaryngology-Head and Neck Surgery University of Miami Miller School of Medicine Miami Florida U.S.A
| | - Thomas Walker
- Department of Otolaryngology-Head and Neck Surgery University of Miami Miller School of Medicine Miami Florida U.S.A
| | - Simon Angeli
- Department of Otolaryngology-Head and Neck Surgery University of Miami Miller School of Medicine Miami Florida U.S.A
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Adriztina I, Adenin LI, Lubis YM. Efficacy of Boric Acid as a Treatment of Choice for Chronic Suppurative Otitis Media and Its Ototoxicity. Korean J Fam Med 2018; 39:2-9. [PMID: 29383205 PMCID: PMC5788841 DOI: 10.4082/kjfm.2018.39.1.2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/05/2017] [Accepted: 08/29/2017] [Indexed: 01/29/2023] Open
Abstract
Chronic suppurative otitis media (CSOM) is one of the most common chronic infectious diseases worldwide, especially affecting children. The patients or the parents of the affected children are often worried about the cost of medical visits, prescription medicines, or inconsistently effective medication. The complications of CSOM have been greatly reduced because of the development of antibiotics; however, the irrational use of antibiotics has led to the emergence of organisms resistant to the commonly used drugs. Owing to the increase in antibiotic resistance, the development of new treatments that will efficiently eradicate infectious microorganisms has become imperative. Boric acid solutions are effective in the treatment of CSOM because of their acidic effect. Various databases, such as the PubMed, The Cochrane Library, and SciELO, were searched for references related to the efficacy of boric acid in the treatment of mucosal CSOM, as well as its ototoxicity. The search revealed that boric acid is relatively effective in treating CSOM, especially at a high concentration. Boric acid in distilled water was found safe in animal studies. However, the ototoxicity of boric acid concentrations higher than 4% needs further evaluation, considering the effectivity of boric acid at high concentrations.
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Affiliation(s)
- Indri Adriztina
- Department of Otorhinolaryngology, Universitas Sumatera Utara, Medan, North Sumatera, Indonesia
| | - Linda Irwani Adenin
- Department of Otorhinolaryngology, H. Adam Malik General Hospital, Medan, North Sumatera, Indonesia
| | - Yuliani Mardiati Lubis
- Department of Otorhinolaryngology, H. Adam Malik General Hospital, Medan, North Sumatera, Indonesia
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Sønderholm M, Bjarnsholt T, Alhede M, Kolpen M, Jensen PØ, Kühl M, Kragh KN. The Consequences of Being in an Infectious Biofilm: Microenvironmental Conditions Governing Antibiotic Tolerance. Int J Mol Sci 2017; 18:E2688. [PMID: 29231866 PMCID: PMC5751290 DOI: 10.3390/ijms18122688] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/27/2017] [Accepted: 12/06/2017] [Indexed: 12/22/2022] Open
Abstract
The main driver behind biofilm research is the desire to understand the mechanisms governing the antibiotic tolerance of biofilm-growing bacteria found in chronic bacterial infections. Rather than genetic traits, several physical and chemical traits of the biofilm have been shown to be attributable to antibiotic tolerance. During infection, bacteria in biofilms exhibit slow growth and a low metabolic state due to O₂ limitation imposed by intense O₂ consumption of polymorphonuclear leukocytes or metabolically active bacteria in the biofilm periphery. Due to variable O₂ availability throughout the infection, pathogen growth can involve aerobic, microaerobic and anaerobic metabolism. This has serious implications for the antibiotic treatment of infections (e.g., in chronic wounds or in the chronic lung infection of cystic fibrosis patients), as antibiotics are usually optimized for aerobic, fast-growing bacteria. This review summarizes knowledge about the links between the microenvironment of biofilms in chronic infections and their tolerance against antibiotics.
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Affiliation(s)
- Majken Sønderholm
- Costerton Biofilm Centre, Department of Immunology and Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Thomas Bjarnsholt
- Costerton Biofilm Centre, Department of Immunology and Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Clinical Microbiology, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark.
| | - Maria Alhede
- Costerton Biofilm Centre, Department of Immunology and Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Mette Kolpen
- Costerton Biofilm Centre, Department of Immunology and Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Clinical Microbiology, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark.
| | - Peter Ø Jensen
- Costerton Biofilm Centre, Department of Immunology and Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Clinical Microbiology, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark.
| | - Michael Kühl
- Marine Biology Section, Department of Biology, University of Copenhagen, DK-3000 Elsinore, Denmark.
- Climate Change Cluster, University of Technology Sydney, Ultimo NSW 2007, Australia.
| | - Kasper N Kragh
- Costerton Biofilm Centre, Department of Immunology and Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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31
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Recurrent otorrhea in chronic suppurative otitis media: is biofilm the missing link? Eur Arch Otorhinolaryngol 2017; 274:2741-2747. [PMID: 28466356 DOI: 10.1007/s00405-017-4586-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 04/22/2017] [Indexed: 12/18/2022]
Abstract
Dispersal of bacteria from a biofilm in the middle ear, serving as a bacterial reservoir, could explain the recurrent and chronic nature of chronic suppurative otitis media (CSOM). The objective of this study is to investigate if the same strains of bacteria could be detected in repeated episodes of otorrhea in CSOM. In a prospective case series at a primary healthcare clinic in Nuuk, Greenland, patients with more than 14 days of otorrhea were included consecutively. Samples for culturing and biofilm analysis were taken at enrollment and at any subsequent episode with otorrhea. Participants were treated with daily saline irrigation and Ciprofloxacin eardrops for 7-14 days. Biofilm was identified in otorrhea in 81% (17/21) of participants at enrollment. Multispecies infections dominated with Non-typeable Haemophilus Influenzae (NTHI), Staphyloccocus aureus, and anaerobes being the most frequent pathogens. After the initial treatment, 19 (90%) had dry ears. Median observation period was 140 days (range 14-280) where 13 participants had one or more recurrences. Median time to first recurrence was 60 days (range 14-197). Among the 13 with recurrence, three individuals had the same genotype of bacteria at a subsequent episode. Another two had the same phenotype (NTHI). The remaining eight had new multispecies infections. We confirmed a high rate of biofilm in CSOM. However, the clinical implication might be of minor importance when treating with irrigation and antibiotic eardrops, as recurrent episodes of otorrhea were dominated by new pathogens in each episode.
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32
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Jufas N, Marchioni D, Tarabichi M, Patel N. Endoscopic Anatomy of the Protympanum. Otolaryngol Clin North Am 2016; 49:1107-19. [DOI: 10.1016/j.otc.2016.05.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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33
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Molecular Microbiological Profile of Chronic Suppurative Otitis Media. J Clin Microbiol 2016; 54:2538-46. [PMID: 27487953 DOI: 10.1128/jcm.01068-16] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 07/26/2016] [Indexed: 01/13/2023] Open
Abstract
Chronic suppurative otitis media (CSOM) presents with purulent otorrhea (ear discharge), is characterized by chronic inflammation of the middle ear and mastoid cavity, and contributes to a significant disease burden worldwide. Current antibiotic therapy is guided by swab culture results. In the absence of detailed molecular microbiology studies of CSOM patients, our current understanding of the microbiota of CSOM (and indeed of the healthy ear) remains incomplete. In this prospective study, 24 patients with CSOM were recruited, along with 22 healthy controls. Culture-based techniques and 16S rRNA gene amplicon sequencing were used to profile the bacterial community for each patient. Comparisons between patients with and without cholesteatoma in the middle ear and mastoid cavity were also made. A major finding was that the middle ear of many healthy controls was not sterile, which is contradictory to the results of previous studies. However, sequencing data showed that Staphylococcus aureus, along with a range of other Gram-positive and Gram-negative organisms, were present in all subgroups of CSOM and healthy controls. Large interpatient variability in the microbiota was observed within each subgroup of CSOM and controls, and there was no bacterial community "signature" which was characteristic of either health or disease. Comparisons of the culture results with the molecular data show that culture-based techniques underestimate the diversity of bacteria found within the ear. This study reports the first detailed examination of bacterial profiles of the ear in healthy controls and patients with CSOM.
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Satpathy S, Sen SK, Pattanaik S, Raut S. Review on bacterial biofilm: An universal cause of contamination. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2016. [DOI: 10.1016/j.bcab.2016.05.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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35
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Kragh KN, Hutchison JB, Melaugh G, Rodesney C, Roberts AEL, Irie Y, Jensen PØ, Diggle SP, Allen RJ, Gordon V, Bjarnsholt T. Role of Multicellular Aggregates in Biofilm Formation. mBio 2016; 7:e00237. [PMID: 27006463 PMCID: PMC4807362 DOI: 10.1128/mbio.00237-16] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 11/25/2022] Open
Abstract
UNLABELLED In traditional models ofin vitrobiofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development ofPseudomonas aeruginosabiofilms. We find that the relative fitness of aggregates depends markedly on the density of surrounding single cells, i.e., the level of competition for growth resources. When competition between aggregates and single cells is low, an aggregate has a growth disadvantage because the aggregate interior has poor access to growth resources. However, if competition is high, aggregates exhibit higher fitness, because extending vertically above the surface gives cells at the top of aggregates better access to growth resources. Other advantages of seeding by aggregates, such as earlier switching to a biofilm-like phenotype and enhanced resilience toward antibiotics and immune response, may add to this ecological benefit. Our findings suggest that current models of biofilm formation should be reconsidered to incorporate the role of aggregates in biofilm initiation. IMPORTANCE During the past decades, there has been a consensus around the model of development of a biofilm, involving attachment of single planktonic bacterial cells to a surface and the subsequent development of a mature biofilm. This study presents results that call for a modification of this rigorous model. We show how free floating biofilm aggregates can have a profound local effect on biofilm development when attaching to a surface. Our findings show that an aggregate landing on a surface will eventually outcompete the biofilm population arising from single cells attached around the aggregate and dominate the local biofilm development. These results point to a regime where preformed biofilm aggregates may have a fitness advantage over planktonic cells when it comes to accessing nutrients. Our findings add to the increasingly prominent comprehension that biofilm lifestyle is the default for bacteria and that planktonic single cells may be only a transition state at the most.
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Affiliation(s)
- Kasper N Kragh
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Jaime B Hutchison
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas, USA
| | - Gavin Melaugh
- School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Chris Rodesney
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas, USA
| | - Aled E L Roberts
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Yasuhiko Irie
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Peter Ø Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Stephen P Diggle
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Rosalind J Allen
- School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Vernita Gordon
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas, USA Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Thomas Bjarnsholt
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
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Rybtke M, Hultqvist LD, Givskov M, Tolker-Nielsen T. Pseudomonas aeruginosa Biofilm Infections: Community Structure, Antimicrobial Tolerance and Immune Response. J Mol Biol 2015; 427:3628-45. [DOI: 10.1016/j.jmb.2015.08.016] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/18/2015] [Accepted: 08/20/2015] [Indexed: 02/07/2023]
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Roberts AE, Kragh KN, Bjarnsholt T, Diggle SP. The Limitations of In Vitro Experimentation in Understanding Biofilms and Chronic Infection. J Mol Biol 2015; 427:3646-61. [DOI: 10.1016/j.jmb.2015.09.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/12/2015] [Accepted: 09/01/2015] [Indexed: 11/28/2022]
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Høiby N, Bjarnsholt T, Moser C, Bassi G, Coenye T, Donelli G, Hall-Stoodley L, Holá V, Imbert C, Kirketerp-Møller K, Lebeaux D, Oliver A, Ullmann A, Williams C. ESCMID∗ guideline for the diagnosis and treatment of biofilm infections 2014. Clin Microbiol Infect 2015; 21 Suppl 1:S1-25. [DOI: 10.1016/j.cmi.2014.10.024] [Citation(s) in RCA: 451] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/14/2014] [Accepted: 10/14/2014] [Indexed: 01/22/2023]
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Tolker-Nielsen T. Pseudomonas aeruginosa biofilm infections: from molecular biofilm biology to new treatment possibilities. APMIS 2015:1-51. [PMID: 25399808 DOI: 10.1111/apm.12335] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bacteria in natural, industrial and clinical settings predominantly live in biofilms, i.e., sessile structured microbial communities encased in self-produced extracellular matrix material. One of the most important characteristics of microbial biofilms is that the resident bacteria display a remarkable increased tolerance toward antimicrobial attack. Biofilms formed by opportunistic pathogenic bacteria are involved in devastating persistent medical device-associated infections, and chronic infections in individuals who are immune-compromised or otherwise impaired in the host defense. Because the use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially, biofilm infections where P. aeruginosa plays an important role are described. Subsequently, current insights into the molecular mechanisms involved in P. aeruginosa biofilm formation and the associated antimicrobial tolerance are reviewed. And finally, based on our knowledge about molecular biofilm biology, a number of therapeutic strategies for combat of P. aeruginosa biofilm infections are presented.
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Affiliation(s)
- Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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40
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Nazzari E, Torretta S, Pignataro L, Marchisio P, Esposito S. Role of biofilm in children with recurrent upper respiratory tract infections. Eur J Clin Microbiol Infect Dis 2014; 34:421-9. [PMID: 25318897 DOI: 10.1007/s10096-014-2261-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 10/06/2014] [Indexed: 12/30/2022]
Abstract
Recurrent respiratory tract infections (RRTIs) are very common in children and a major challenge for pediatricians. In the last few years, bacterial biofilms have been linked to RRTIs and antibiotic resistance, and have raised serious concerns regarding the therapeutic management of recurrent middle ear diseases, chronic rhinosinusitis, and recurrent pharyngotonsillitis. This paper aims to review the new insights into biofilm-related upper respiratory tract infections in children and possible therapeutic strategies. It focuses on the clinical implications for recurrent disease and on studies in pediatric patients. Analysis of the literature showed that the involvement of bacterial biofilm in recurrent upper airway tract infections is an emerging problem that may lead to serious concerns about infection control. Despite the large amount of research within this field, detailed insight into the complex structure of bacterial biofilms and the ultrastructural and biochemical mechanisms responsible for its evasion of the immune system and resistance to treatments is currently lacking. In the future, additional emphasis should be placed on biofilm management as a component of therapeutic strategies. This goal can be attained by finding feasible methods for detecting biofilms in vivo and identifying effective methods for administering treatments that eradicate preexisting bacterial biofilms or hinder bacterial adhesion to respiratory cells.
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Affiliation(s)
- E Nazzari
- Pediatric Highly Intensive Care Unit, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda no. 9, 20122, Milan, Italy
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Selective Antibiofilm Effects of Lucilia sericata Larvae Secretions/Excretions against Wound Pathogens. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:857360. [PMID: 25013449 PMCID: PMC4074965 DOI: 10.1155/2014/857360] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/07/2014] [Indexed: 12/18/2022]
Abstract
Background. Maggot debridement therapy (MDT), using Lucilia sericata larvae, represents efficient, simple, and low-cost therapy for the treatment of chronic wounds. Aim. The aim was to investigate the antibiofilm activity of maggot excretions/secretions (ES) against biofilm of wound isolates Staphylococcus aureus (S. aureus), Enterobacter cloacae (E. cloacae), and Proteus mirabilis (P. mirabilis). Methods. Quantification of biofilm formation, was carried out using a microtiter plate assay. Proteolytic activity of maggot ES was performed using skim milk agar plates. A solid phase extraction and reverse phase HPLC C18 chromatography were employed to the isolate of maggot ES antibiofilm compounds. Results. Maggot ES at 100 mg/mL concentration significantly reduced biofilm formation thus disrupting established biofilm of E. cloacae. Heat-treated ES did not show any antibiofilm activity towards E. cloacae. Similar results were obtained in the case of S. aureus; however, the heat-treatment of maggot ES did not affect its antibiofilm activity. Moreover, a compound with molecular weight of 25 kDa exhibiting antibiofilm activity was identified in maggot ES. On the other hand, maggot ES protected and even stimulated P. mirabilis biofilm formation. Conclusions. Our results suggest that maggot ES may act selectively against different bacterial strain.
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Alhede M, Bjarnsholt T, Givskov M, Alhede M. Pseudomonas aeruginosa biofilms: mechanisms of immune evasion. ADVANCES IN APPLIED MICROBIOLOGY 2014; 86:1-40. [PMID: 24377853 DOI: 10.1016/b978-0-12-800262-9.00001-9] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes (PMNs). In this chapter, the interplay between P. aeruginosa and the PMNs in chronic infections is discussed with focus on the role of rhamnolipids and extracellular DNA.
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Affiliation(s)
- Maria Alhede
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.
| | - Thomas Bjarnsholt
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Michael Givskov
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Morten Alhede
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
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Mucosal biofilm detection in chronic otitis media: a study of middle ear biopsies from Greenlandic patients. Eur Arch Otorhinolaryngol 2014; 272:1079-85. [PMID: 24477340 DOI: 10.1007/s00405-014-2886-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 01/09/2014] [Indexed: 12/31/2022]
Abstract
The objectives of this study were to examine middle ear biopsies from Greenlandic patients with chronic otitis media (COM) for the presence of mucosal biofilms and the bacteria within the biofilms. Thirty-five middle ear biopsies were obtained from 32 Greenlandic COM patients admitted to ear surgery. All biopsies were examined by means of peptide nucleic acid-fluorescent in situ hybridization (PNA-FISH), and if possible culture and polymerase chain reaction (PCR) of the 16s rDNA and sequencing. Light microscopy and confocal laser scanning microscopy were used. Skin biopsies from 23 of the patients served as controls. PNA-FISH showed morphological signs of biofilms in 15 out of 35 (43 %) middle ear biopsies. In the control skin biopsies, there were signs of biofilms in eight out of 23 biopsies (30 %), probably representing skin flora. PCR and 16s sequencing detected bacteria in seven out of 20 (35 %) usable middle ear biopsies, and in two out of ten (20 %) usable control samples. There was no association between biofilm findings and PCR and 16s sequencing. Staphylococci were the most common bacteria in bacterial culture. We found evidence of bacterial biofilms in 43 % of middle ear biopsies from patients COM. The findings may indicate that biofilms are a part of the pathogenesis in recurrent episodes of ear discharge in COM, but further investigations are necessary.
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Gu X, Keyoumu Y, Long L, Zhang H. Detection of bacterial biofilms in different types of chronic otitis media. Eur Arch Otorhinolaryngol 2013; 271:2877-83. [PMID: 24132653 DOI: 10.1007/s00405-013-2766-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 10/04/2013] [Indexed: 11/26/2022]
Abstract
Biofilms are organized bacterial communities that may be homogeneous or heterogeneous. They play a significant role in the pathogenesis of chronic nasal sinusitis, chronic tonsillitis, cholesteatomas, and device-related infections. Despite this, few studies have been done that examine the presence of bacterial biofilms in tissues from patients with different types of COM or middle ear cholesteatomas. In the current study, we examined the presence of biofilms in surgical tissue specimens from humans with chronic ear infections using scanning electron microscopy (SEM). We hypothesize that bacterial biofilms present differently in patients with different types of chronic otitis media. Our results provide new insights regarding treatment of chronic otitis media. A prospective study was conducted in which middle ear tissues were obtained from 38 patients who underwent tympanoplasty and/or tympanomastoid surgery due to chronic ear infections. A total of 50 middle and mastoid tissue samples were processed for SEM analysis. In addition, 38 middle ear secretion specimens were obtained for routine bacterial culture analysis. Bacterial biofilms were present in 85 % (11 of 13) of patients with middle ear cholesteatoma, 92 % (12/13) of patients with chronic otitis suppurative media (CSOM), and 16 % of patients (2/12) with tympanic membrane perforation (TMP). Fungal biofilms were found in two cases of cholesteatoma. The positive coincidence rate between bacterial biofilms visualized by SEM and bacteria detected by culture was 82 %. Our findings suggest that bacterial biofilms are very common in CSOM and middle ear cholesteatomas. Positive bacterial cultures imply the presence of biofilm formation in CSOM and cholesteatomas. As such, our results provide new insights regarding treatment of chronic otitis media.
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Affiliation(s)
- Xingzhi Gu
- Department of Otorhinolaryngology, The First Affiliated Hospital of Xinjiang Medical University, 137 Carp Mountain South Road, Ürümqi, 830011, China
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Bjarnsholt T, Alhede M, Alhede M, Eickhardt-Sørensen SR, Moser C, Kühl M, Jensen PØ, Høiby N. The in vivo biofilm. Trends Microbiol 2013; 21:466-74. [PMID: 23827084 DOI: 10.1016/j.tim.2013.06.002] [Citation(s) in RCA: 487] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/26/2013] [Accepted: 06/05/2013] [Indexed: 11/15/2022]
Abstract
Bacteria can grow and proliferate either as single, independent cells or organized in aggregates commonly referred to as biofilms. When bacteria succeed in forming a biofilm within the human host, the infection often becomes very resistant to treatment and can develop into a chronic state. Biofilms have been studied for decades using various in vitro models, but it remains debatable whether such in vitro biofilms actually resemble in vivo biofilms in chronic infections. In vivo biofilms share several structural characteristics that differ from most in vitro biofilms. Additionally, the in vivo experimental time span and presence of host defenses differ from chronic infections and the chemical microenvironment of both in vivo and in vitro biofilms is seldom taken into account. In this review, we discuss why the current in vitro models of biofilms might be limited for describing infectious biofilms, and we suggest new strategies for improving this discrepancy.
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Affiliation(s)
- Thomas Bjarnsholt
- Department of International Health, Immunology, and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology 9301, Juliane Mariesvej 22, Copenhagen University Hospital, Copenhagen, Denmark.
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Cayé-Thomasen P, Hermansson A, Bakaletz L, Hellstrøm S, Kanzaki S, Kerschner J, Lim D, Lin J, Mason K, Spratley J. Panel 3: Recent advances in anatomy, pathology, and cell biology in relation to otitis media pathogenesis. Otolaryngol Head Neck Surg 2013; 148:E37-51. [PMID: 23536531 DOI: 10.1177/0194599813476257] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND OBJECTIVES The pathogenesis of otitis media (OM) involves a number of factors related to the anatomy, pathology, and cell biology of the middle ear, the mastoid, the Eustachian tube, and the nasopharynx. Although some issues of pathogenesis are fairly well established, others are only marginally indicated by current knowledge, and yet others remain undisclosed. The objective of this article is to provide a state-of-the-art review on recent scientific achievements in the pathogenesis of OM, as related to anatomy, pathology, and cell biology. DATA SOURCES PubMed, Ovid Medline, and Cochrane Library. REVIEW METHODS Articles published on the pathogenesis of OM and the anatomy, pathology, and cell biology of the middle ear, the mastoid, the Eustachian tube, and the nasopharynx between January 2007 and June 2011 were identified. Among almost 1900 abstracts, the authors selected 130 articles for full article review and inclusion in this report. RESULTS New knowledge on a number of issues emerged, including cell-specific expression and function of fluid transportation and innate immune system molecules, mucous cell metaplasia, mucin expression, bacterial adherence, and epithelial internalization, as well as the occurrence, composition, dynamics, and potential role of bacterial biofilm. In addition, the potential role of gastroesophageal reflux disease and cigarette smoke exposure has been explored further. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE Over the past 4 years, considerable scientific progress has been made on the pathogenesis of OM, as related to issues of anatomy, pathology, and cell biology. Based on these new achievements and a sustained lack of essential knowledge, suggestions for future research are outlined.
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Affiliation(s)
- Per Cayé-Thomasen
- Department of Oto-rhino-laryngology, Head and Neck Surgery, University Hospital of Copenhagen, Copenhagen, Denmark.
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Torretta S, Drago L, Marchisio P, Gaffuri M, Clemente IA, Pignataro L. Topographic distribution of biofilm-producing bacteria in adenoid subsites of children with chronic or recurrent middle ear infections. Ann Otol Rhinol Laryngol 2013; 122:109-13. [PMID: 23534125 DOI: 10.1177/000348941312200206] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Bacterial biofilms have been found in the adenoids of children with recurrent acute otitis media (AOM) and persistent otitis media with effusion (OME). However, the possible difference in biofilm-producing bacteria (BPBs) between the adenoid surface at the nasopharyngeal dome (ND) and near the ostium of the eustachian tube (ET) has not been investigated. This study aimed to assess the difference in BPBs between adenoid biopsy specimens of the ND and those taken near the pharyngeal ostium of the ET in children with chronic adenoiditis with recurrent AOM and/or persistent OME. METHODS We collected adenoid biopsy specimens from the ND and ET during transoral endoscopic adenoidectomy to assess BPB by means of spectrophotometric analysis. RESULTS We collected 135 adenoid biopsy specimens from 45 children. BPBs were detected significantly (p = 0.04) more frequently in the ET samples than in the ND samples, mainly Staphylococcus aureus. Although the prevalence of S aureus was slightly greater in the ND samples, and that of Streptococcus pneumoniae and Moraxella catarrhalis was slightly greater in the ET samples, these differences were not statistically significant. CONCLUSIONS The fact that BPBs were significantly more frequently located near the ostium of the ET suggests that the adenoids are a reservoir for bacteria and indicates that hypertrophic adenoids (particularly hypertrophy near the ostium of the ET) play a role in recurrent AOM and/or OME.
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Affiliation(s)
- Sara Torretta
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
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Qaisar U, Luo L, Haley CL, Brady SF, Carty NL, Colmer-Hamood JA, Hamood AN. The pvc operon regulates the expression of the Pseudomonas aeruginosa fimbrial chaperone/usher pathway (cup) genes. PLoS One 2013; 8:e62735. [PMID: 23646138 PMCID: PMC3639982 DOI: 10.1371/journal.pone.0062735] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 03/25/2013] [Indexed: 02/03/2023] Open
Abstract
The Pseudomonas aeruginosa fimbrial structures encoded by the cup gene clusters (cupB and cupC) contribute to its attachment to abiotic surfaces and biofilm formation. The P. aeruginosa pvcABCD gene cluster encodes enzymes that synthesize a novel isonitrile functionalized cumarin, paerucumarin. Paerucumarin has already been characterized chemically, but this is the first report elucidating its role in bacterial biology. We examined the relationship between the pvc operon and the cup gene clusters in the P. aeruginosa strain MPAO1. Mutations within the pvc genes compromised biofilm development and significantly reduced the expression of cupB1-6 and cupC1-3, as well as different genes of the cupB/cupC two-component regulatory systems, roc1/roc2. Adjacent to pvc is the transcriptional regulator ptxR. A ptxR mutation in MPAO1 significantly reduced the expression of the pvc genes, the cupB/cupC genes, and the roc1/roc2 genes. Overexpression of the intact chromosomally-encoded pvc operon by a ptxR plasmid significantly enhanced cupB2, cupC2, rocS1, and rocS2 expression and biofilm development. Exogenously added paerucumarin significantly increased the expression of cupB2, cupC2, rocS1 and rocS2 in the pvcA mutant. Our results suggest that pvc influences P. aeruginosa biofilm development through the cup gene clusters in a pathway that involves paerucumarin, PtxR, and different cup regulators.
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Affiliation(s)
- Uzma Qaisar
- Department of Immunology and Molecular Microbiology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Liming Luo
- Department of Immunology and Molecular Microbiology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Cecily L. Haley
- Department of Immunology and Molecular Microbiology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Sean F. Brady
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University and Howard Hughes Medical Institute, New York, New York, United States of America
| | - Nancy L. Carty
- Department of Immunology and Molecular Microbiology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Jane A. Colmer-Hamood
- Department of Immunology and Molecular Microbiology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Abdul N. Hamood
- Department of Immunology and Molecular Microbiology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
- * E-mail:
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Neutrophil extracellular traps and bacterial biofilms in middle ear effusion of children with recurrent acute otitis media--a potential treatment target. PLoS One 2013; 8:e53837. [PMID: 23393551 PMCID: PMC3564866 DOI: 10.1371/journal.pone.0053837] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 12/03/2012] [Indexed: 11/25/2022] Open
Abstract
Background Bacteria persist within biofilms on the middle ear mucosa of children with recurrent and chronic otitis media however the mechanisms by which these develop remain to be elucidated. Biopsies can be difficult to obtain from children and their small size limits analysis. Methods In this study we aimed to investigate biofilm presence in middle ear effusion (MEE) from children with recurrent acute otitis media (rAOM) and to determine if these may represent infectious reservoirs similarly to those on the mucosa. We examined this through culture, viability staining and fluorescent in situ hybridisation (FISH) to determine bacterial species present. Most MEEs had live bacteria present using viability staining (32/36) and all effusions had bacteria present using the universal FISH probe (26/26). Of these, 70% contained 2 or more otopathogenic species. Extensive DNA stranding was also present. This DNA was largely host derived, representing neutrophil extracellular traps (NETs) within which live bacteria in biofilm formations were present. When treated with the recombinant human deoxyribonuclease 1, Dornase alfa, these strands were observed to fragment. Conclusions Bacterial biofilms, composed of multiple live otopathogenic species can be demonstrated in the MEEs of children with rAOM and that these contain extensive DNA stranding from NETs. The NETs contribute to the viscosity of the effusion, potentially contributing to its failure to clear as well as biofilm development. Our data indicates that Dornase alfa can fragment these strands and may play a role in future chronic OM treatment.
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Daniel M, Imtiaz-Umer S, Fergie N, Birchall JP, Bayston R. Bacterial involvement in otitis media with effusion. Int J Pediatr Otorhinolaryngol 2012; 76:1416-22. [PMID: 22819485 DOI: 10.1016/j.ijporl.2012.06.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 06/14/2012] [Accepted: 06/16/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Otitis media with effusion (OME), a common chronic childhood condition affecting hearing, is thought to be a result of bacterial infection, with biofilms recently implicated. Although bacterial DNA can be detected by polymerase chain reaction in 80% of patients, typically fewer than half of effusions are positive using standard culture techniques. We adopted an alternative approach to demonstrating bacteria in OME, using a bacterial viability stain and confocal laser scanning microscopy (CLSM): staining allows detection of live bacteria without requiring growth on culture, while CLSM allows demonstration of the three-dimensional structure typical of biofilms. METHODS Effusion samples were collected at the time of ventilation tube insertion, analysed with CLSM and bacterial viability stain, and extended culture techniques performed with the intention of capturing all possible organisms. RESULTS Sixty-two effusions (42 patients) were analysed: 28 (45.2%) were culture-positive, but 51 (82.3%) were CLSM-positive. Combining the two techniques demonstrated live bacteria in 57 (91.8%) samples. Using CLSM, bacteria exhibited biofilm morphology in 25 effusions and were planktonic in 26; the proportion of samples exhibiting biofilm morphology was similar in the culture-positive and culture-negative groups (50.0% and 48.3%, respectively). Biofilm samples contained an average of 1.7 different bacterial isolates and planktonic samples 2.0, with the commonest bacteria identified being coagulase-negative staphylococci. CONCLUSION Live bacteria are present in most effusions, strongly suggesting that bacteria and biofilms are important in the aetiopathogenesis of OME.
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Affiliation(s)
- M Daniel
- Otorhinolaryngology Head & Neck Surgery, The University of Nottingham, Nottingham University Hospitals Queen's Medical Centre, Nottingham NG7 2UH, UK
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