All posts by Postępy Mikrobiologii

Walidacja i weryfikacja metod i testów diagnostycznych w laboratorium mikrobiologicznym

Validation and verification methods and diagnostic tests in the microbiology laboratory
E. Stefaniuk, K. Bosacka, W. Hryniewicz
19 July 2017

1. Wprowadzenie. 2. Walidacja i weryfikacja metod i testów diagnostycznych w laboratorium mikrobiologicznym. 2.1. Weryfikacja i walidacja metody. 2.2. Weryfikacja i walidacja testów. 2.2. Walidacja metod biologicznych. 3. Procedura walidacyjna – zasady. 3.1. Plan walidacji. 3.2. Protokół walidacji. 4. Rewalidacja. 5. Procedura weryfikacji metody komercyjnej – przykład. 5.1. Cel badania. 5.2. Plan badania. 5.2.1. Zasada wykonania oznaczeń. 5.2.2. Parametry i kryteria akceptacji. 5.2.2.1. Dokładność. 5.2.2.2. Precyzja. 5.3. Wyniki i obliczenia. 5.3.1. Dokładność. 5.3.2. Precyzja w warunkach powtarzalności. 5.3.3. Precyzja w warunkach odtwarzalności. 5.3.4. Przedstawienie precyzji w formie graficznej. 5.4. Wyniki a kryteria akceptacji. 5.5. Stwierdzenie walidacyjne. 6. Podsumowanie

Abstract: There are a number of measurable factors evidence of the “quality” of laboratory tests. They allow to evaluate the laboratory proficiency, staff competency and applied technologies. There is a duty of each laboratory to prove that the method meets the quality requirements and is suitable for a particular purpose and result is credible. There are many acts that require verification and validation procedures in a laboratory. The aim of this article is to present a concept of validation and verification in microbiology and give an explanation of the difference between these processes. In this study a validation and verification parameters for the methods (e.g. accuracy, precision, repeatability, reproducibility, ruggedness, LOD, LOQ, linearity) were also described and they were divided into quantitative and qualitative methods. Parameters for tests validation and verification included sensitivity, specificity PPV, NPV. In the second part of the study an example of verification process of commercial methods is presented. A various the steps of the verification tests, the rules for calculation parameters and conclusions are also shown.

1. Introduction. 2. Validation and verification methods and diagnostic tests in the laboratory. 2.1. Verification and validation of the methods. 2.2. Verification and validation of the tests. 2.2. Validation of the biological methods. 3. Validation procedure – rules. 3.1. Validation scheme. 3.2. Validation protocol. 4. Revalidation. 5. Verification procedure of the commercial method – an example. 5.1. Aim of the study. 5.2. The study plan. 5.2.1. The principle study. 5.2.2. The parameters and acceptance criteria. 5.2.2.1. Accuracy. 5.2.2.2. Precision. 5.3. Results and calculations. 5.3.1. Accuracy. 5.3.2. Precision under repeatability conditions. 5.3.3. Precision under reproducibility conditions. 5.3.4. Presentation of precision in graphical form. 5.4. Results and the acceptance criteria. 5.5. The statement validation. 6. Summary

Autor: Postępy Mikrobiologii
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Nowoczesne metody zwalczania biofilmu bakteryjnego

Novel methods of bacterial biofilm elimination
M. Maciejewska, M. Bauer, M. Dawgul
3 July 2017

1. Wstęp. 2. Etapy powstawania biofilmu, a oporność na antybiotyki. 3. Strategie zapobiegania tworzenia się biofilmu. 3.1. Celowanie w początkową fazę rozwoju biofilmu. 3.1.1. Związki niskocząsteczkowe (Small Molecules). 3.1.2. Ingerencja w quorum sensing. 3.1.3. Przeciwciała. 3.1.4. Biofilm drobnoustrojów niepatogennych. 3.2. Modyfikacja biomateriałów w celu zwiększenia ich odporności na adhezję drobnoustrojów. 3.2.1. Materiały antyadhezyjne. 3.2.2. Powłoki bakteriobójcze/bakteriostatyczne. 4. Metody eradykacji biofilmu. 4.1. Fizyczne metody eradykacji biofilmu. 4.2. Biologiczne metody eradykacji biofilmu. 4.3. Chemiczne metody eradykacji biofilmu. 5. Peptydy przeciwdrobnoustrojowe. 6. Podsumowanie

Abstract: Bacterial biofilm is defined as a sessile, tridimensional microbial community composed of bacteria immersed in a polysaccharide matrix. The structures can grow on human tissues or medical devices resulting in biofilm related infections, which are very often impossible to treat with the commonly used antibiotics. Due to their resistance to the conventional antimicrobial therapy, efficient methods of treatment as well as prophylaxis need to be developed.
Biofilm formation can be reduced by inhibiting the process of adhesion and by interfering with quorum sensing system. Very promising is also the application of appropriate antibodies or use of non-pathogenic bacterial strains. Another approach focuses on the surface modifications in order to obtain the resistance to microbial colonization.
Disruption of mature structures can be achieved by several physical, chemical and biological methods. The novel approaches, which are currently being under intensive investigation, include: phage therapy, matrix targeting enzymes, photodynamic therapy and antimicrobial peptides. The above-mentioned strategies are described in the presented work with a special focus on antimicrobial peptides as the potential tool for prophylaxis as well as elimination of mature biofilms.

1. Introduction. 2. Stages of biofilm formation and the resistance to antibiotics. 3. Strategies of prevention of biofilm formation. 3.1. Targeting the initial phase of biofilm formation. 3.1.1. Small Molecules. 3.1.2. Interference in quorum sensing. 3.1.3. Antibodies. 3.1.4. Biofilm of non-pathogenic microorganisms. 3.2. Modification of biomaterials for increased resistance to microbial adhesion. 3.2.1. Anti-adhesive materials. 3.2.2. Bacteriostatic/bactericidal coatings. 4. Methods for biofilm eradication. 4.1. Physical methods for biofilm eradication. 4.2. Biological methods for biofilm eradication. 4.3. Chemical methods for biofilm eradication. 5. Antimicrobial peptides. 6. Conclusions

Autor: Postępy Mikrobiologii
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Oddziaływanie fungicydów na mikroorganizmy w środowisku glebowym

The impact of fungicides on soil microorganisms
S. Sułowicz, Z. Piotrowska-Seget
3 July 2017

1. Charakterystyka fungicydów. 2. Wpływ presji fungicydowej na ekosystem glebowy. 3. Oddziaływanie fungicydów na mikroorganizmy glebowe. 4. Triazole – charakterystyka i wpływ na ekosystem glebowy. 5. Podsumowanie

Abstract: Modern agriculture depends heavily on pesticides, including fungicides. Fungicides such as triazoles, when applied every year, may accumulate in soils leading to the development of resistance to the applied compounds and subsequently to the spread of resistance genes to other fungi. Additionally, fungicides can impact non-target soil microorganisms by reducing their biomass, changing microbial activity, and altering functional and structural diversity of bacterial and fungal communities. Soil quality is closely linked to the microbial activity, therefore, the effects of fungicides on non-target soil microorganisms increase concerns about the fertility of soil. This new knowledge about specific interaction between fungicides and soil microorganisms has to be taken into consideration in designing a new strategy for soil protection.

1. Fungicides. 2. The influence of fungicide pressure on soil ecosystem. 3. The impact of fungicides on soil microorganisms. 4. Triazoles – their characteristic features and influence on soil ecosystem. 5. Conclusions

Autor: Postępy Mikrobiologii
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Wykorzystanie odpadów pochodzących z przemysłu rolno-spożywczego do produkcji biomasy drożdży paszowych Candida utilis

The use of agri-food industry waste for the production of Candida utilis fodder yeast biomass
A. Kurcz, S. Błażejak, A. M. Kot, A. Bzducha-Wróbel
3 July 2017

1. Wstęp. 2. Biotechnologiczne wykorzystanie drożdży Candida utilis. 3. Surowce wykorzystywane do produkcji biomasy drożdży paszowych. 4. Produkcja biopaliw i gospodarka odpadami z produkcji biodiesla. 4.1. Wykorzystanie glicerolu w procesach biotechnologicznych 5. Produkcja skrobi ziemniaczanej. 5.1. Charakterystyka odpadowej ziemniaczanej wody sokowej i kierunki jej wykorzystania. 6. Podsumowanie

Abstract: Both glycerol and potato wastewater are difficult-to-utilize waste from industrial processing. Thus, it is necessary to search for new economical methods of waste utilization to obtain products of higher value, decrease the production costs and protect the environment. One of the solutions to this problem might be simultaneous application of glycerol and potato wastewater as components of culture media for the production of Candida utilis fodder yeast biomass. This yeast strain is able to use glycerol from culture media as the only source of carbon, while the deproteinated potato wastewater might be the source of nitrogenous compounds and minerals. As a result, there is the possibility to obtain C. utilis fodder yeast biomass rich in such valuable nutrients as protein, fat, β-glucans, vitamins and microelements.

1. Introduction. 2. Biotechnological use of the yeast Candida utilis. 3. Raw materials used for the production of fodder yeast biomass. 4. Production of biofuels and the management of biodiesel post-production waste. 4.1. The use of glycerol in biotechnological processes. 5. Production of potato starch. 5.1. Characteristics of potato wastewater and its potential usage. 6. Conclusion

Autor: Postępy Mikrobiologii
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Założenia i perspektywy wykorzystania żywych wektorów bakteryjnych we współczesnej wakcynologii

Principles and perspectives of using live bacterial vectors in modern vaccinology
K. Roeske, R. Stachowiak, J. Bielecki
3 July 2017

1. Wakcynologia – rys historyczny i perspektywy. 2. Swoista (nabyta) odpowiedź immunologiczna. 3. Komórki efektorowe odpowiedzi typu komórkowego. 4. Prezentacja antygenu i jego rozpoznanie przez limfocyty. 5. Pamięć immunologiczna. 6. Szczepionki indukujące odpowiedź komórkową. 7. Szczepionki podjednostkowe. 8. Adiuwanty. 9. Szczepionki wektorowe. 10. Bakterie patogenne jako wektory szczepionkowe. 11. Bakterie niepatogenne jako wektory szczepionkowe. 12. Podsumowanie

Abstract: Various strategies can be used to deliver antigens to the cytosol of antigen presenting cells, e.g. using nanoparticles, liposomes, immune stimulating complexes, viruses or bacteria. Among them, the use of bacterial carriers constitutes probably the most studied strategy. Depending on the extra- or intracellular life cycle of the pathogen, different immune responses are required for protection. Vaccines formulated on the basis of killed whole cells or isolated cell fractions tend to induce strong antibody response, however, they are ineffective at inducing cellular immunity. Due to these characteristics such antigens are used mainly to immunize against extracellular pathogens. Conversely, live attenuated mutants induce a broad range of immune responses including CD8+ T cell response, thereby leading to effective immunization against intracellular pathogens. Besides adjuvant properties provided by carried molecular patterns, live bacterial carriers have other important advantages, such as the ability to mimic natural infection and possibility to be administered in a needle-free manner. Remarkably, vector-based vaccines can be designed to enable induction of immune response against their own or carried heterologous antigens. Both pathogenic and commensal microorganisms are used in the next generation vaccine design, however, due to the potential risk of conversion to a virulent strain and causing infection or the loss of immunogenic potency, pathogenic vectors are less likely to use. Questions concerning safety which have arisen with the advent of live-attenuated bacterial vectors made the researchers turn their attention to non-pathogenic bacteria.

1. Vaccinology – historical background and perspectives. 2. Acquired immunity. 3. Effector cells of cell-mediated immune response. 4. Antigen presentation and its recognition by T-cells. 5. Immunological memory. 6. Vaccines inducing cellular immune response. 7. Subunit vaccines. 8. Adjuvants. 9. Vector vaccines. 10. Pathogenic bacteria as vaccine vectors. 11. Non-pathogenic bacteria as vaccine vectors. 12. Summary

Autor: Postępy Mikrobiologii
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Current Issue

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Advancements of Microbiology
Volume 63 (2024): Issue 1

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PTM

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