Special Issue "Microbial Biofilms and Human Infections"

A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Medical Microbiology".

Deadline for manuscript submissions: closed (30 June 2017)

Special Issue Editors

Guest Editor
Prof. Dr. Gianfranco Donelli

Microbial Biofilm Laboratory (LABIM), IRCCS "Fondazione Santa Lucia", Via Ardeatina 306, 00179 Rome, Italy
Website | E-Mail
Fax: +39 06 51501306
Interests: microbiology; microbial biofilms; healthcare-associated infections; biomaterial-associated infections; role of toxins and other virulence factors in microbial pathogenesis
Guest Editor
Dr. Claudia Vuotto

Microbial Biofilm Laboratory (LABIM), IRCCS "Fondazione Santa Lucia", Via Ardeatina 306, 00179 Rome, Italy
Website | E-Mail
Interests: microbial biofilms; healthcare-associated infections; biomaterial-associated infections; antibiotic resistance, probiotics

Special Issue Information

Dear Colleagues,

A large number of microorganisms are known to give rise, by adhering to surfaces, to sessile communities defined as biofilms, sometimes established by single microbial species, but, more often, by different aerobic and/or anaerobic species. Such complex biological systems, consisting of microorganisms that multiply inside a self-produced matrix, mainly constituted by exopolysaccharides, behave as a consortia, acting in a coordinated manner. During the development of these communities, the sessile cells acquire physiological characteristics, differing from those of planktonic cells, particularly with regard to the production of extracellular polymeric substances, growth rate, expressed genes, and increased horizontal gene transfer.

Today, multidrug- and extensively drug-resistant pathogens, able to grow as biofilms, represent a serious public health concern, with the zeal for the biofilm coming from their ability to often make antibiotics inadequate, thus, giving rise to chronic and/or recurrent infections. Such biofilms are considered to be responsible for a wide variety of community-acquired and healthcare-associated infections, especially those involving the respiratory tract, the genito-urinary apparatus and surgical wounds. Additionally, human infections related to the implant of medical devices, such as urinary catheters, central venous catheters, prostheses, biliary stents, and so on, are considered to be associated with the establishment of microbial biofilms on their surfaces.

The aim of this Special Issue, dedicated to "Microbial biofilm and Human Infections", is to collect updated reviews, as well as selected research articles, on the mechanisms underlying the formation of pathogenic biofilms, the development of appropriate laboratory methods to detect biofilm-related human infections, and the set up of innovative anti-biofilm therapies or preventive strategies.

Prof. Gianfranco Donelli
Dr. Claudia Vuotto
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

 

Keywords

  • biofilm-related human infections
  • microbial pathogens
  • antimicrobial resistance
  • medical devices
  • anti-biofilm compounds
  • antimicrobial surfaces
  • laboratory diagnosis

Published Papers (5 papers)

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Research

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Open AccessArticle Diagnostic Value of Endotracheal Aspirates Sonication on Ventilator-Associated Pneumonia Microbiologic Diagnosis
Microorganisms 2017, 5(3), 62; https://doi.org/10.3390/microorganisms5030062
Received: 10 August 2017 / Revised: 15 September 2017 / Accepted: 17 September 2017 / Published: 20 September 2017
Cited by 1 | PDF Full-text (6161 KB) | HTML Full-text | XML Full-text
Abstract
Microorganisms are able to form biofilms within respiratory secretions. Methods to disaggregate such biofilms before utilizing standard, rapid, or high throughput diagnostic technologies may aid in pathogen detection during ventilator associated pneumonia (VAP) diagnosis. Our aim was to determine if sonication of endotracheal [...] Read more.
Microorganisms are able to form biofilms within respiratory secretions. Methods to disaggregate such biofilms before utilizing standard, rapid, or high throughput diagnostic technologies may aid in pathogen detection during ventilator associated pneumonia (VAP) diagnosis. Our aim was to determine if sonication of endotracheal aspirates (ETA) would increase the sensitivity of qualitative, semi-quantitative, and quantitative bacterial cultures in an animal model of pneumonia caused by Pseudomonas aeruginosa or by methicillin resistant Staphylococcus aureus (MRSA). Material and methods: P. aeruginosa or MRSA was instilled into the lungs or the oropharynx of pigs in order to induce severe VAP. Time point assessments for qualitative and quantitative bacterial cultures of ETA and bronchoalveolar lavage (BAL) samples were performed at 24, 48, and 72 h after bacterial instillation. In addition, at 72 h (autopsy), lung tissue was harvested to perform quantitative bacterial cultures. Each ETA sample was microbiologically processed with and without applying sonication for 5 min at 40 KHz before bacterial cultures. Sensitivity and specificity were determined using BAL as a gold-standard. Correlation with BAL and lung bacterial burden was also determined before and after sonication. Assessment of biofilm clusters and planktonic bacteria was performed through both optical microscopy utilizing Gram staining and Confocal Laser Scanning Microscopy utilizing the LIVE/DEAD®BacLight kit. Results: 33 pigs were included, 27 and 6 from P. aeruginosa and MRSA pneumonia models, respectively. Overall, we obtained 85 ETA, 69 (81.2%) from P. aeruginosa and 16 (18.8%) from MRSA challenged pigs. Qualitative cultures did not significantly change after sonication, whereas quantitative ETA cultures did significantly increase bacterial counting. Indeed, sonication consistently increased bacterial burden in ETAs at 24, 48, and 72 h after bacterial challenge. Sonication also improved sensitivity of ETA quantitative cultures and maintained specificity at levels previously reported and accepted for VAP diagnosis. Conclusion: The use of sonication in ETA respiratory samples needs to be clinically validated since sonication could potentially improve pathogen detection before standard, rapid, or high throughput diagnostic methods used in routine microbial diagnostics. Full article
(This article belongs to the Special Issue Microbial Biofilms and Human Infections)
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Open AccessArticle Hyperbaric Oxygen Therapy is Ineffective as an Adjuvant to Daptomycin with Rifampicin Treatment in a Murine Model of Staphylococcus aureus in Implant-Associated Osteomyelitis
Microorganisms 2017, 5(2), 21; https://doi.org/10.3390/microorganisms5020021
Received: 19 March 2017 / Revised: 18 April 2017 / Accepted: 19 April 2017 / Published: 25 April 2017
Cited by 5 | PDF Full-text (1967 KB) | HTML Full-text | XML Full-text
Abstract
Implant-associated infections caused by bacterial biofilms are difficult to treat. Surgical intervention is often necessary to cure the patient, as the antibiotic recalcitrance of biofilms renders them untreatable with conventional antibiotics. Intermittent hyperbaric oxygen treatment (HBOT) has been proposed as an adjuvant to [...] Read more.
Implant-associated infections caused by bacterial biofilms are difficult to treat. Surgical intervention is often necessary to cure the patient, as the antibiotic recalcitrance of biofilms renders them untreatable with conventional antibiotics. Intermittent hyperbaric oxygen treatment (HBOT) has been proposed as an adjuvant to conventional antibiotic treatment and it has been speculated that combining HBOT with antibiotics could improve treatment outcomes for biofilm infections. In this study we addressed whether HBOT could improve treatment outcomes of daptomycin and rifampicin combination therapy. The effect of HBOT on the treatment outcomes of daptomycin and rifampicin against implant-associated osteomyelitis was quantified in a murine model. In total, 80 mice were randomized into two groups receiving antibiotics, either alone or in combination with daily intermittent HBOT (304 kPa for 60 min) following injection of antibiotics. Treatment was initiated 11 days after animals were infected with Staphylococcus aureus and treatment duration was 14 days. We found that HBOT did not improve the cure rate and did not reduce the bacterial load on the implant surface or in the surrounding tissue. Cure rates of daptomycin + rifampicin were 40% in infected tibias and 75% for implants while cure rates for HBOT-daptomycin + rifampicin were 50% and 85%, respectively, which were not significantly higher (Fisher’s exact test). While it is encouraging that the combination of daptomycin and rifampicin is very effective, our study demonstrates that this efficacy cannot be improved by adjuvant HBOT. Full article
(This article belongs to the Special Issue Microbial Biofilms and Human Infections)
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Review

Jump to: Research

Open AccessReview The Status of Biofilms in Penile Implants
Microorganisms 2017, 5(2), 19; https://doi.org/10.3390/microorganisms5020019
Received: 24 February 2017 / Revised: 4 April 2017 / Accepted: 10 April 2017 / Published: 18 April 2017
Cited by 1 | PDF Full-text (184 KB) | HTML Full-text | XML Full-text
Abstract
Erectile dysfunction is prevalent among men and will continue to become more so with the aging population. Of the available treatment options, implantable prosthetic devices are typically thought of as a third line treatment even though they have the highest satisfaction rate and [...] Read more.
Erectile dysfunction is prevalent among men and will continue to become more so with the aging population. Of the available treatment options, implantable prosthetic devices are typically thought of as a third line treatment even though they have the highest satisfaction rate and continually improving success rates. Infection and mechanical failure are the most common reasons for implant revision in the past. Since the development of more reliable devices, bacterial biofilms are coming to the forefront of discussion as causes of required revision. Biofilms are problematic as they are ubiquitous and exceedingly difficult to prevent or treat. Full article
(This article belongs to the Special Issue Microbial Biofilms and Human Infections)
Open AccessReview Approaches to Dispersing Medical Biofilms
Microorganisms 2017, 5(2), 15; https://doi.org/10.3390/microorganisms5020015
Received: 27 February 2017 / Revised: 22 March 2017 / Accepted: 31 March 2017 / Published: 1 April 2017
Cited by 25 | PDF Full-text (447 KB) | HTML Full-text | XML Full-text
Abstract
Biofilm-associated infections pose a complex problem to the medical community, in that residence within the protection of a biofilm affords pathogens greatly increased tolerances to antibiotics and antimicrobials, as well as protection from the host immune response. This results in highly recalcitrant, chronic [...] Read more.
Biofilm-associated infections pose a complex problem to the medical community, in that residence within the protection of a biofilm affords pathogens greatly increased tolerances to antibiotics and antimicrobials, as well as protection from the host immune response. This results in highly recalcitrant, chronic infections and high rates of morbidity and mortality. Since as much as 80% of human bacterial infections are biofilm-associated, many researchers have begun investigating therapies that specifically target the biofilm architecture, thereby dispersing the microbial cells into their more vulnerable, planktonic mode of life. This review addresses the current state of research into medical biofilm dispersal. We focus on three major classes of dispersal agents: enzymes (including proteases, deoxyribonucleases, and glycoside hydrolases), antibiofilm peptides, and dispersal molecules (including dispersal signals, anti-matrix molecules, and sequestration molecules). Throughout our discussion, we provide detailed lists and summaries of some of the most prominent and extensively researched dispersal agents that have shown promise against the biofilms of clinically relevant pathogens, and we catalog which specific microorganisms they have been shown to be effective against. Lastly, we discuss some of the main hurdles to development of biofilm dispersal agents, and contemplate what needs to be done to overcome them. Full article
(This article belongs to the Special Issue Microbial Biofilms and Human Infections)
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Open AccessReview Microbial Biofilms and Chronic Wounds
Microorganisms 2017, 5(1), 9; https://doi.org/10.3390/microorganisms5010009
Received: 17 January 2017 / Accepted: 4 March 2017 / Published: 7 March 2017
Cited by 22 | PDF Full-text (618 KB) | HTML Full-text | XML Full-text
Abstract
Background is provided on biofilms, including their formation, tolerance mechanisms, structure, and morphology within the context of chronic wounds. The features of biofilms in chronic wounds are discussed in detail, as is the impact of biofilm on wound chronicity. Difficulties associated with the [...] Read more.
Background is provided on biofilms, including their formation, tolerance mechanisms, structure, and morphology within the context of chronic wounds. The features of biofilms in chronic wounds are discussed in detail, as is the impact of biofilm on wound chronicity. Difficulties associated with the use of standard susceptibility tests (minimum inhibitory concentrations or MICs) to determine appropriate treatment regimens for, or develop new treatments for use in, chronic wounds are discussed, with alternate test methods specific to biofilms being recommended. Animal models appropriate for evaluating biofilm treatments are also described. Current and potential future therapies for treatment of biofilm-containing chronic wounds, including probiotic therapy, virulence attenuation, biofilm phenotype expression attenuation, immune response suppression, and aggressive debridement combined with antimicrobial dressings, are described. Full article
(This article belongs to the Special Issue Microbial Biofilms and Human Infections)
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