Browsing tag: biofilm

Zakażenia układu moczowego z udziałem Proteus mirabilis – rola biofilmu i inkrustacji cewnika urologicznego

Urinary tract infections caused by Proteus mirabilis – role of the biofilm and the encrustation of the urological catheter
D. M. Matusiak
10 August 2017

1. Zakażenia układu moczowego. 2. Proteus mirabilis – charakterystyka ogólna. 3. Biofilm – definicja, opis. 4. Biofilm na cewniku urologicznym i jego inkrustacja. 5. Zapobieganie i leczenie CAUTI u osób poddanych cewnikowaniu. 6. Podsumowanie

Abstract: Urinary tract infection (UTI) is one of the most common nosocomial infections. Proteus mirabilis is important Gram-negative, dimorphic and motile pathogen (Enterobacteriaceae family), causing UTI – especially in catheterized patients. Key elements leading to CAUTI are: catheter colonization, mono- or multi-species biofilm formation and the long period of the catherization. Biofilm is microorganisms’ protective and dynamic community, attached to surface and embedded in extracellular matrix (mainly polysaccharides). P. mirabilis can easily adhere to catheter surface and cause it’s encrustation and blockage (due to urine alkalization by urease, leading to struvite and apatite crystals precipitation). Struvite contains magnesium ammonium phosphate and apatite – calcium phosphate. Urine flow obstruction can elicit pyelonephritis. Other uropathogens, producing urease e.g. Morganella morganii, Providencia stuartii, Escherichia coli (some strains), Klebsiella pneumoniae rather rarely cause catheter blockage. There have been proposed many solutions, preventing catheter biofilm colonization or disrupting formed consortium. However by this time there is no high-effective and broadly used remedy. One of the solutions is the impregnation of the catheters with silver, EDTA, antiseptics (e.g. triclosan, chlorohexidine), antibiotics, heparin or lactoferrin – short-term and insufficient-concentration release, risk of the resistance onset, sometimes non-wide spectrum activity. This solutions are generally moderately effective and postpones the emergence of bacteruria. Another approach (experimental) for example is to inhibit urease or the quorum sensing. The surface of the catheter also could be more hydrophilic and smooth, to inhibit the bacterial attachment.

1. Urinary tract infections. 2. Proteus mirabilis – general description. 3. Biofilm – definition, characterization. 4. Biofilm on urinary catheter and it’s encrustation. 5. Prophylaxis and treatment of CAUTI in catheterized patients. 6. Summary

Autor: Postępy Mikrobiologii
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Sekrecja pęcherzyków błonowych jako mechanizm promujący infekcje H. pylori

Secretion of outer membrane vesicles as a mechanism promoting H. pylori infections
P. Krzyżek
8 August 2017

1. Wstęp. 2. Sekrecja pęcherzyków błonowych u H. pylori. 3. Proteom pęcherzyków błonowych H. pylori. 4. Transport czynników wirulencji poprzez OMV. 4.1. Toksyna VacA. 4.2. Onkoproteina CagA. 4.3. Inne substancje. 5. Udział OMV w formowaniu biofilmu. 5.1. Funkcje biofilmu. 5.2. Zaangażowanie OMV w tworzenie biofilmu u bakterii. 5.3. Zaangażowanie OMV w tworzenie biofilmu u H. pylori. 5.4. Funkcja strukturalna zewnątrzkomórkowego DNA H. pylori. 6. Zewnątrzkomórkowe DNA jako nośnik informacji. 6.1. Wpływ na wirulencję. 6.2. Transformacja. 6.3. Naturalna kompetencja H. pylori. 7. Podsumowanie

Abstract: Helicobacter pylori commonly colonizes the human gastric mucosa. Infections with this microorganism can contribute to serious health consequences, such as peptic ulceration, gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue lymphoma. Chronic persistence of this bacteria in the host organism is probably strongly dependent on the secretion of outer membrane vesicles (OMV). These organelles are small, electron-dense, extracellular structures which are secreted in large amounts during stressful conditions, among others. H. pylori OMV mediate transfer of virulence factors such as toxins and immunomodulatory compounds. They contribute to avoiding a response from the host immune system and inducing chronic gastritis. OMV secretion also affects the formation of cell aggregates, microcolonies and biofilm matrix. Enhanced OMV production is connected to maintenance of direct contact through cell-cell and
cell-surface interactions. A key component of OMV, which determines their structural function, is extracellular DNA (eDNA) anchored to the surface of these organelles. eDNA associated with OMV additionally determines the genetic recombination in the process of horizontal gene transfer. H. pylori is naturally competent for genetic transformation and is constantly capable of DNA uptake from the environment. The natural competence state promotes the assimilation of eDNA anchored to the OMV surface. This is probably dependent on ComB and ComEC components, which are involved in the transformation process. For this reason, the OMV secretion mediates intensive exchange of genetic material, promotes adaptation to changing environmental conditions and enables persistent infecting of the gastric mucosa by H. pylori.

1. Introduction. 2. Secretion of outer membrane vesicles by H. pylori. 3. Proteome of H. pylori outer membrane vesicles. 4. Transport of virulence factors through OMV. 4.1. Toxin VacA. 4.2. Oncoprotein CagA. 4.3. Other substances. 5. OMV involvement in biofilm formation. 5.1. Functions of biofilm. 5.2. OMV influence on bacterial biofilm formation. 5.3. OMV influence on biofilm formation by H. pylori. 5.4. Structural function of H. pylori extracellular DNA. 6. Extracellular DNA as an information carrier. 6.1. Influence on virulence. 6.2. Transformation. 6.3. Natural competence of H. pylori. 7. Conclusions

Autor: Postępy Mikrobiologii
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Biofilm, pompy MDR i inne mechanizmy oporności Stenotrophomonas maltophilia na związki przeciwbakteryjne

Biofilm, MDR efflux pumps and other mechanisms of Stenotrophomonas maltophilia resistance to antibacterial substances
O. Zając, A. E. Laudy, S. Tyski
28 July 2017

1. Wstęp. 2. Leczenie zakażeń S. maltophilia. 3. Oporność na związki przeciwbakteryjne. 3.1. Oporność na antybiotyki i chemioterapeutyki. 3.2. Oporność na środki dezynfekcyjne. 3.3. Oporność na jony metali. 4. Systemy pomp. 4.1. Rodzina RND. 4.2. Rodzina MFS. 4.3. Rodzina ABC. 4.4. Pompa FuaABC. 5. Biofilm bakteryjny i system quorum sensing. 6. Podsumowanie

Abstract: Stenotrophomonas maltophilia is a non-fermentative Gram-negative rod, which can cause many infections, including pneumonia and bacteremia, especially in immunocompromised or long-term hospitalized patients. The infections are difficult in therapy, because clinical isolates are usually highly resistant to many classes of antimicrobial agents, moreover, they are able to colonize medical devices and epithelial cells and form biofilm. The several resistance mechanisms of S. maltophilia to antibacterial agents have been described, among them: β-lactamases production, production of other enzymes modifying antibiotics structure and activity of multidrug efflux pumps (MDR). Up to date, eight MDR efflux pumps have been identified in S. maltophilia strains. These pumps belong to three different families of MDR pumps and RND family plays the most important role in multidrug resistance.

1. Introduction. 2. Treatment of S. maltophilia infections. 3. Resistance to antibacterial substances. 3.1. Resistance to antibiotics and chemotherapeutics. 3.2. Resistance to disinfectants. 3.3. Resistance to metals. 4. Efflux systems. 4.1. RND family. 4.2. MFS family. 4.3. ABC family. 4.4. The FuaABC efflux pump. 5. Biofilm and quorum sensing system. 6. Summary

Autor: Postępy Mikrobiologii
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Mikrobiom liści roślin uprawnych

The microbiome on the leaves of crop plants
K. Kucharska, U. Wachowska
27 July 2017

1. Wstęp. 2. Liść jako siedlisko mikroorganizmów. 3. Społeczności mikroorganizmów na liściach. 4. Mikrobiom. 5. Pozytywne oddziaływanie mikroorganizmów na rośliny. 6. Negatywne oddziaływanie mikroorganizmów na rośliny. 7. Struktura zbiorowisk mikroorganizmów zasiedlających liście. 8. Techniki badawcze zbiorowisk mikroorganizmów zasiedlających liście. 9. Podsumowanie

Abstract: The leaves of crop plants are colonized by numerous microorganisms which live on leaf surface or penetrate into the tissues, despite nutrient deficiencies and exposure to adverse environmental conditions. Leaf-colonizing microorganisms exhibit a broad range of relationships with the host plant, thus forming a complex interactive ecosystem. The functions of microbial communities and their effects on the host plant have not been fully elucidated to date. Expanding our knowledge in this area can have important practical implications, including more effective pathogen and disease control. Rapidly developing molecular techniques can provide valuable information about the interactions between microbes and the host plants they colonize. The aim of this study was to characterize microorganisms colonizing the leaves of crop plants, and to discuss the benefits and threats related to their presence in this ecological niche.

1. Introduction. 2. Leaf as habitation of microorganisms. 3. Community of microorganisms on the leaves. 4. The microbiome. 5. Positive interaction of microorganisms on plants. 6. Negative interaction of microorganisms on plants. 7. Structure of microorganism communities colonizing leaves. 8. Techniques of study microorganism communities colonizing leaves. 9. Summary

Autor: Postępy Mikrobiologii
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Bakteriofagi i drapieżniki bakterii jako czynniki limitujące liczbę bakterii w środowisku

Bacteriophages and bacterial predators as agents limiting the amount of bacteria in the environment
A. Wierzbicka-Woś, W. Deptuła
26 July 2017

1. Wprowadzenie. 2. Bakteriofagi a bakterie w środowisku. 3. Bakterie drapieżne z grupy BALO a bakterie w środowisku. 4. Pierwotniaki a bakterie w środowisku. 5. Drapieżniki bakterii a biofilm. 6. Mechanizmy obronne bakterii oraz ich interakcje z drapieżnikami. 7. Praktyczne wykorzystanie drapieżników bakterii. 8. Podsumowanie

Abstract: Bacterial predators, such as Bdellovibrio and Bdellovibrio like organisms (BALOs), protozoa and bacteriophages, are the major cause of bacterial mortality. Howeverthe correlations between these microorganisms enable their coexistance in the same ecological niche. This review presents the interactions between bacterial prey and their predators, and bacteriophages. In addition, it describes bacterial adaptations helping bacteria to prevent the attack. Taking into account current problems with increasing antibiotic resistance of pathogenic microorganisms, this observations can lead us to the discovery of novel antimicrobial compounds, which are common in nature, and could be used in the future against animal and human pathogens. Moreover, these microorganisms might be also a potentialsource of novel biocatalysts, which could be applied in biotechnological processes.

1. Introduction. 2. Bacteriophages and bacteria in the environment. 3. Bacterial predators from BALO and bacteria in the environment. 4. Protozoa and bacteria in the environment. 5. Bacterial predators and biofilm. 6. Defense mechanisms of bacteria and their interactions with predators. 7. Practical use of bacterial predators. 8. Summary

Autor: Postępy Mikrobiologii
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Advancements of Microbiology
Volume 63 (2024): Issue 3

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PTM

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