Microbial Biofilms in Urinary Tract Infections and Prostatitis: Etiology, Pathogenicity, and Combating strategies

Urinary tract infections (UTIs) are one of the most important causes of morbidity and health care spending affecting persons of all ages. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. UTIs associated with microbial biofilms developed on catheters account for a high percentage of all nosocomial infections and are the most common source of Gram-negative bacteremia in hospitalized patients. The purpose of this mini-review is to present the role of microbial biofilms in the etiology of female UTI and different male prostatitis syndromes, their consequences, as well as the challenges for therapy.

Innovative Self-Cleaning and Biocompatible Polyester Textiles Nano-Decorated with Fe-N-Doped Titanium Dioxide

The development of innovative technologies to modify natural textiles holds an important impact for medical applications, including the prevention of contamination with microorganisms, particularly in the hospital environment. In our study, Fe and N co-doped TiO₂ nanoparticles have been obtained via the hydrothermal route, at moderate temperature, followed by short thermal annealing at 400 °C. These particles were used to impregnate polyester (PES) materials which have been evaluated for their morphology, photocatalytic performance, antimicrobial activity against bacterial reference strains, and in vitro biocompatibility on human skin fibroblasts. Microscopic examination and quantitative assays have been used to evaluate the cellular morphology and viability, cell membrane integrity, and inflammatory response. All treated PES materials specifically inhibited the growth of Gram-negative bacilli strains after 15 min of contact, being particularly active against Pseudomonas aeruginosa. PES fabrics treated with photocatalysts did not affect cell membrane integrity nor induce inflammatory processes, proving good biocompatibility. These results demonstrate that the treatment of PES materials with TiO₂-1% Fe–N particles could provide novel biocompatible fabrics with short term protection against microbial colonization, demonstrating their potential for the development of innovative textiles that could be used in biomedical applications for preventing patients’ accidental contamination with microorganisms from the hospital environment.

Periodontitis and Periodontal Disease - Innovative Strategies for Reversing the Chronic Infectious and Inflammatory Condition by Natural Products

Oral microbiota of the mouth is the most diverse microbial community in the human body and plays a decisive role in the emergence and evolution of gingival pathology, contributing as well to the host general health condition, based on complex interactions established between the microbial community members and the host. A specific shift in the quantity and diversity of the microbial community developed on dental and mucosal surfaces, could lead to the occurrence of chronic inflammation mediated by the overproduction of pro-inflammatory cytokines. The mechanical treatment and current medication efficiency for the periodontal disease is limited in time due to the rapid plaque forming. Also, the antimicrobial treatment is limited by the sessile growth of the microorganisms, resulting in a poor biofilm penetration by biocides or antibiotics. In line with that, the attention of the scientific community shifted to ethnopharmacology as a complementary, or alternative therapeutic option for fighting infections with resistant bacteria. The vegetal and bee products are an important source of bioactive compounds, acting as harmless antimicrobials and periodontal inflammation suppressors. Vegetable bioproducts have been proven to exhibit multiple antipathogenic effects, such as microbicidal activity, virulence attenuation, and synergistic effects between the components found in the complex vegetal matrixes, or with conventional biocides, as well as immunomodulatory effects. The purpose of this review is to highlight the importance of vegetable products as a possible complementary treatment for periodontitis and their potential for the development of innovative therapeutic strategies.

Photocatalytic, Antimicrobial and Biocompatibility Features of Cotton Knit Coated with Fe-N-Doped Titanium Dioxide Nanoparticles

Our research was focused on the evaluation of the photocatalytic and antimicrobial properties, as well as biocompatibility of cotton fabrics coated with fresh and reused dispersions of nanoscaled TiO₂-1% Fe-N particles prepared by the hydrothermal method and post-annealed at 400 °C. The powders were characterized by X-ray diffraction (XRD), Mössbauer spectroscopy and X-ray photoelectron spectroscopy. The textiles coated with doped TiO₂ were characterized by scanning electron microscopy and energy dispersive X-ray analyses, and their photocatalytic effect by trichromatic coordinates of the materials stained with methylene blue and coffee and exposed to UV, visible and solar light. The resulting doped TiO₂ consists of a mixture of prevailing anatase phase and a small amount (~15%-20%) of brookite, containing Fe³⁺ and nitrogen. By reusing dispersions of TiO₂-1% Fe-N, high amounts of photocatalysts were deposited on the fabrics, and the photocatalytic activity was improved, especially under visible light. The treated fabrics exhibited specific antimicrobial features, which were dependent on their composition, microbial strain and incubation time. The in vitro biocompatibility evaluation on CCD-1070Sk dermal fibroblasts confirmed the absence of cytotoxicity after short-term exposure. These results highlight the potential of TiO₂-1% Fe-N nanoparticles for further use in the development of innovative self-cleaning and antimicrobial photocatalytic cotton textiles. However, further studies are required in order to assess the long-term skin exposure effects and the possible particle release due to wearing.

Recognition and Impact of Host-derived Molecules on Bacterial Cell-to-cell Signalling Pathways

Microbe-host signalling is now a well accepted concept and an intensively studied research field. Although some of the observed bacterial phenotypes are attributed to host-recognition and inter-kingdom signalling, most of them are not relying on a proved molecular mechanism. Recent progress revealed some recognition and signalling pathways for host molecules in bacterial cells, which try to explain their modulatory effect on growth and virulence. Since the current knowledge on the field is poor and debatable, the purpose of this paper is to review and discuss the research performed in order to elucidate the ways by which microbial cells recognize and decode the host molecule signals.

Fabrication, Characterization, and Evaluation of Bionanocomposites Based on Natural Polymers and Antibiotics for Wound Healing Applications

The aim of our research activity was to obtain a biocompatible nanostructured composite based on naturally derived biopolymers (chitin and sodium alginate) loaded with commercial antibiotics (either Cefuroxime or Cefepime) with dual functions, namely promoting wound healing and assuring the local delivery of the loaded antibiotic. Compositional, structural, and morphological evaluations were performed by using the thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and fourier transform infrared spectroscopy (FTIR) analytical techniques. In order to quantitatively and qualitatively evaluate the biocompatibility of the obtained composites, we performed the tetrazolium-salt (MTT) and agar diffusion in vitro assays on the L929 cell line. The evaluation of antimicrobial potential was evaluated by the viable cell count assay on strains belonging to two clinically relevant bacterial species (i.e., Escherichia coli and Staphylococcus aureus).

Virulence and resistance features of Pseudomonas aeruginosa strains isolated from chronic leg ulcers

Background

The purpose of this study was to evaluate the virulence profiles of Pseudomonas aeruginosa clinical strains recently isolated from patients hospitalized for chronic leg ulcers in the Dermatology Department of Central Military Emergency University Hospital “Carol Davila”, Bucharest, Romania.

Methods

The phenotypic screening evaluated eight soluble virulence factors (haemolysins, lecithinase, lipase, caseinase, gelatinase, amylase, DNase, aesculin hydrolysis), as well as adherence ability (Cravioto adapted method) and invasion capacity on HeLa cells (gentamicin protection assay). Seven virulence genes encoding for protease IV, 3 exoenzymes (exoS, exoT, exoU), two phospholipases plcH- haemolytic phospholipase C and plcN- non-haemolytic phospholipase C) and alginate were investigated by PCR.

Results

The pore forming toxins and enzymes were expressed in variable proportions, the majority of the tested strains producing beta haemolysin (92.3 %), lipase (76.9 %) and lecithinase (61.5 %). The most frequent virulence genes detected in the analyzed strains were the ExoT (100 %) and AlgD (92.3 %) genes, genes codifying for phospholipases (84.6 % each of them) and for protease IV (61.5 %).

Conclusions

This study reveals that correlating virulence profiles and infection clinical outcome is very useful for setting up efficient preventive and therapeutic procedures for hospitalized patients with chronic leg ulcers and positive P. aeruginosa cultures.

Insights on Metal Based Dental Implants and their Interaction with the Surrounding Tissues

At present, the use of dental implants is a very common practice as tooth loss is a frequent problem and can occur as a result of disease or trauma. An implant is usually made of biocompatible materials that do not cause rejection reactions and allow the implant union with the respective bone. To achieve this goal, the implant surface may have different structures and coatings, generally used to increase the adherence of the implant to the bone and to decrease the risk of the periimplantar inflammatory reactions. This review gives some insights of the metal based materials used for dental implants, their limits, improvement strategies as well as the pathophysiology, diagnosis, treatment and prevention of periimplantary diseases.

Microbial biofilms: impact on the pathogenesis of periodontitis, cystic fibrosis, chronic wounds and medical device-related infections

The majority of chronic infections are associated with mono- or polymicrobial biofilms, having a significant impact on the patients' quality of life and survival rates. Although the use of medical devices revolutionized health care services and significantly improved patient outcomes, it also led to complications associated with biofilms and to the emergence of multidrug resistant bacteria. Immunocompromised patients, institutionalized or hospitalized individuals, elderly people are at greater risk due to life-threatening septic complications, but immunocompetent individuals with predisposing genetic or acquired diseases can also be affected, almost any body part being able to shelter persistent biofilms. Moreover, chronic biofilm-related infections can lead to the occurrence of systemic diseases, as in the case of chronic periodontitis, linked to atherosclerosis, cardiovascular disease and diabetes. The more researchers discover, new unknown issues add up to the complexity of biofilm infections, in which microbial species establish relationships of cooperation and competition, and elaborate phenotypic differentiation into functional, adapted communities. Their interaction with the host's immune system or with therapeutic agents contributes to the complex puzzle that still misses a lot of pieces. In this comprehensive review we aimed to highlight the microbial composition, developmental stages, architecture and properties of medical biofilms, as well as the diagnostic tools used in the management of biofilm related infections. Also, we present recently acquired knowledge on the etiopathogenesis, diagnosis and treatment of four chronic diseases associated with biofilm development in tissues (chronic periodontitis, chronic lung infection in cystic fibrosis, chronic wounds) and artificial substrata (medical devices-related infections).

Metallic-based micro and nanostructures with antimicrobial activity

The spectacular progress of research in the nanotechnology field led to the achievement of important knowledge of materials at the atomic and molecular scale and the extent of the use of nanoparticles in the design of medical products, ecological processes, cosmetics and other biotechnological applications. One of the current focuses of the medical applications of nanotechnology is the development of new strategies to inhibit the activity of different microorganisms. The purpose of this review was to present the antimicrobial activity of metal cations in micro- and nanoparticulate forms and the dependence of this biological activity on shape, size and physico-chemical conditions.

Significance of serum antibodies against HSP 60 and HSP 70 for the diagnostic of infectious diseases

Heat shock proteins (HSP) represent important antigenic targets for the immune response, playing an important role in the pathology and infectious diseases control. The purpose of this work was to investigate the levels of HSP60 and HSP70 specific antibodies in the bloodstream of patients with different bacterial infections and cancer, in order to evaluate their potential role as diagnosis markers of different infectious diseases. Detection of specific anti-HSP 60 and HSP 70 serum levels was performed by ELISA. Statistical analysis of data by multivariate logistic regression was performed using GraphPadPrism software and statistical tests based on chi-square and Student t-test. High levels of anti-HSP60 were found in patients with localized infections, while the levels of anti- HSP70 were higher in the group with generalized infections. The serum levels of both anti-HSP 60 and anti-HSP70 were significantly increased in patients with Gram-negative bacterial infections, as compared with patients harbouring infections produced by Gram-positive and fungal strains, demonstrating their potential use as additional diagnosis and prognosis markers in infections with this etiology.

Biomedical applications of synthetic, biodegradable polymers for the development of anti-infective strategies

The emergence of antibiotic resistance in microbial strains is representing one of the major threats to public health worldwide, due to the decreased or total cancelling of the available antibiotics effectiveness, correlated with the slow development of novel antibiotics. Due to their excellent biodegradability and biocompatibility, the synthetic polymers could find a lot of biomedical applications, such as the development of biomaterials with optimized properties and of drug delivery systems. This review is focusing on the applications of synthetic, biodegradable polymers for the improvement of antiinfective therapeutic and prophylactic agents (i.e., antimicrobial and anti-inflammatory agents and vaccines) activity, as well as for the design of biomaterials with increased biocompatibility and resistance to microbial colonization.

Challenges in initiating and conducting personalized cancer therapy trials: perspectives from WINTHER, a Worldwide Innovative Network (WIN) Consortium trial

Advances in 'omics' technology and targeted therapeutic molecules are together driving the incorporation of molecular-based diagnostics into the care of patients with cancer. There is an urgent need to assess the efficacy of therapy determined by molecular matching of patients with particular targeted therapies. WINTHER is a clinical trial that uses cutting edge genomic and transcriptomic assays to guide treatment decisions. Through the lens of this ambitious multinational trial (five countries, six sites) coordinated by the Worldwide Innovative Networking Consortium for personalized cancer therapy, we discovered key challenges in initiation and conduct of a prospective, omically driven study. To date, the time from study concept to activation has varied between 19 months at Gustave Roussy Cancer Campus in France to 30 months at the Segal Cancer Center, McGill University (Canada). It took 3+ years to be able to activate US sites due to national regulatory hurdles. Access to medications proposed by the molecular analysis remains a major challenge, since their availability through active clinical trials is highly variable over time within sites and across the network. Rules regarding the off-label use of drugs, or drugs not yet approved at all in some countries, pose a further challenge, and many biopharmaceutical companies lack a simple internal mechanism to supply the drugs even if they wish to do so. These various obstacles should be addressed to test and then implement precision medicine in cancer.

Snapshot on carbapenemase-producing Pseudomonas aeruginosa and Acinetobacter baumannii in Bucharest hospitals reveals unusual clones and novel genetic surroundings for blaOXA-23

OBJECTIVES

The present study was designed to provide a snapshot on carbapenemase-producing Pseudomonas aeruginosa (n=11) and Acinetobacter baumannii (n=7) isolates in hospitalized patients (November 2011, January-March 2012) from two main hospitals in Bucharest, south Romania.

METHODS

Clonality among isolates was established by PFGE, MLST and Fourier transform infrared spectroscopy. Carbapenemases were screened by the Blue-Carba test, PCR and sequencing. Transferability of blaOXA-23 was tested by conjugation and plasmid typing (number, size and identity) was assessed by S1-PFGE, replicon typing, hybridization and PCR mapping.

RESULTS

All P. aeruginosa isolates carried chromosomally located blaVIM-2, associated with a common class 1 integron (aacA7-blaVIM-2) or an atypical configuration (aacA7-blaVIM-2-dfrB5-tniC). These isolates belonged to unusual lineages; mostly ST233 disseminated in one hospital unit, with ST364 and ST1074 also being detected. A. baumannii isolates carried blaOXA-23 in Tn2008, which was found truncating a TnaphA6 transposon located in a common 60 kb GR6 (aci6) pABKp1-like conjugative plasmid in highly related CC92 clones (ST437, ST764 and ST765), where CC stands for clonal complex.

CONCLUSIONS

Our results show the spread of VIM-2-producing P. aeruginosa and OXA-23-producing A. baumannii clinical isolates in two hospitals from Bucharest and highlight a peculiar population structure in this Eastern European country. Also, we demonstrate the dissemination of a common and conjugative aci6 pABKp1-like plasmid scaffold in different A. baumannii clones and we report the first known identification of Tnaph6-carrying pACICU2-like plasmids in Europe.

Efficiency of vanilla, patchouli and ylang ylang essential oils stabilized by iron oxide@C14 nanostructures against bacterial adherence and biofilms formed by Staphylococcus aureus and Klebsiella pneumoniae clinical strains

Biofilms formed by bacterial cells are associated with drastically enhanced resistance against most antimicrobial agents, contributing to the persistence and chronicization of the microbial infections and to therapy failure. The purpose of this study was to combine the unique properties of magnetic nanoparticles with the antimicrobial activity of three essential oils to obtain novel nanobiosystems that could be used as coatings for catheter pieces with an improved resistance to Staphylococcus aureus and Klebsiella pneumoniae clinical strains adherence and biofilm development. The essential oils of ylang ylang, patchouli and vanilla were stabilized by the interaction with iron oxide@C₁₄ nanoparticles to be further used as coating agents for medical surfaces. Iron oxide@C₁₄ was prepared by co-precipitation of Fe⁺² and Fe⁺³ and myristic acid (C₁₄) in basic medium. Vanilla essential oil loaded nanoparticles pelliculised on the catheter samples surface strongly inhibited both the initial adherence of S. aureus cells (quantified at 24 h) and the development of the mature biofilm quantified at 48 h. Patchouli and ylang-ylang essential oils inhibited mostly the initial adherence phase of S. aureus biofilm development. In the case of K. pneumoniae, all tested nanosystems exhibited similar efficiency, being active mostly against the adherence K. pneumoniae cells to the tested catheter specimens. The new nanobiosystems based on vanilla, patchouli and ylang-ylang essential oils could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with anti-adherence and anti-biofilm properties.

Immunomodulatory effect of non-viable components of probiotic culture stimulated with heat-inactivated Escherichia coli and Bacillus cereus on holoxenic mice

Background

Competition of probiotic bacteria with other species from the intestinal microbiota involves different mechanisms that occur regardless of probiotics’ viability. The objective of this paper was to assess the cytokine serum levels in holoxenic mice after oral administration of non-viable components (NVC) of Enterococcus faecium probiotic culture stimulated with heat-inactivated Escherichia coli and Bacillus cereus in comparison to NVC of unstimulated E. faecium probiotic culture.

Methods

Probiotic E. faecium CMGb 16 culture, grown in the presence of heat-inactivated cultures of E. coli and B. cereus CMGB 102, was subsequently separated into supernatant (SN) and heat-inactivated cellular sediment (CS) fractions by centrifugation. Each NVC was orally administered to holoxenic mice (balb C mouse strain), in three doses, given at 24 hours. Blood samples were collected from the retinal artery, at 7, 14, and 21 days after the first administration of the NVC. The serum concentrations of IL-12 and tumor necrosis factor-alpha (TNF-α) interleukins were assessed by ELISA method.

Results

After the oral administration of SN component obtained from the probiotic culture stimulated with heat-inactivated cultures of B. cereus CMGB 102 and E. coli O28, the serum concentrations of IL-12 were maintained higher in the samples collected at 7 and 14 days post-administration. No specific TNF-α profile could be established, depending on stimulated or non-stimulated probiotic culture, NVC fraction, or harvesting time.

Conclusion

The obtained results demonstrate that non-viable fractions of probiotic bacteria, stimulated by other bacterial species, could induce immunostimulatory effects mediated by cytokines and act, therefore, as immunological adjuvants.

Usnic acid-loaded biocompatible magnetic PLGA-PVA microsphere thin films fabricated by MAPLE with increased resistance to staphylococcal colonization

Due to their persistence and resistance to the current therapeutic approaches, Staphylococcus aureus biofilm-associated infections represent a major cause of morbidity and mortality in the hospital environment. Since (+)-usnic acid (UA), a secondary lichen metabolite, possesses antimicrobial activity against Gram-positive cocci, including S. aureus, the aim of this study was to load magnetic polylactic-co-glycolic acid-polyvinyl alcohol (PLGA-PVA) microspheres with UA, then to obtain thin coatings using matrix-assisted pulsed laser evaporation and to quantitatively assess the capacity of the bio-nano-active modified surface to control biofilm formation by S. aureus, using a culture-based assay. The UA-loaded microspheres inhibited both the initial attachment of S. aureus to the coated surfaces, as well as the development of mature biofilms. In vitro bioevalution tests performed on the fabricated thin films revealed great biocompatibility, which may endorse them as competitive candidates for the development of improved non-toxic surfaces resistant to S. aureus colonization and as scaffolds for stem cell cultivation and tissue engineering.