All posts by Postępy Mikrobiologii

Mycobacterium kansasii: biologia patogenu oraz cechy kliniczne i epidemiologiczne zakażeń

Mycobacterium kansasii: pathogen biology and clinical and epidemiological features of infections
Z. Bakuła, A. Safianowska, M. Nowacka-Mazurek, J. Bielecki, T. Jagielski
28 July 2017

1. Wprowadzenie. 2. Prątki niegruźlicze. 3. Charakterystyka Mycobacterium kansasii. 4. Epidemiologia. 5. Diagnostyka laboratoryjna. 6. Patogeneza i obraz kliniczny. 6.1. Interakcje patogen-gospodarz. 6.2. Źródła zakażeń. 6.3. Czynniki ryzyka. 6.4. Rozpoznanie. 6.5. Obraz kliniczny. 7. Leczenie. 8. Podsumowanie

Abstract: Nontuberculous mycobacteria (NTM) are opportunistic pathogens widely spread in the environment that may produce life-threatening infections in humans. With the increased number of patients suffering from different forms of immunosuppression, there has been a resurgence in interest in NTM and increase in the prevalence of NTM diseases. Although the incidence of Mycobacterium kansasii infections shows significant geographical variability, in most places, M. kansasii ranks first as a cause of pulmonary NTM syndromes in the HIV-negative population and second as a cause of disseminated infection in HIV-positive patients. In Poland, among cases of NTM disease, the number of which has been remarkably on the rise in recent years, those attributable to M. kansasii are in majority. Many epidemiological aspects of M. kansasii infection, concerning the pathogen’s reservoirs, contagiousness, transmission routes and distribution in different geographic regions and among different human populations, are unknown or only poorly understood. As with other NTM, M. kansasii infections are believed to be acquired from environmental exposures rather than by person-to-person transmission. Rarely M. kansasii has been isolated from soil, natural water systems or animals. Instead it has almost exclusively been recovered from municipal tap water, which is considered to be its major environmental reservoir. Culturing of M. kansasii from human tissues may not necessarily represent true infection but a non-pathogenic colonization or contamination. Thus, a reliable diagnosis of M. kansasii disease relies upon an in-depth clinical and laboratory investigation, requiring integration of symptomatological, radiological, and microbiological data. In thoracic imaging, M. kansasii infections may manifest as cavitations, opacities, small nodules and bronchiectasis, most frequently situated in the upper lobes, but lesions may also be present in other sites of the lungs. Treatment of M. kansasii infections is based on a combined and long lasting (at least 15 months) regimen consisting of ethambutol, isoniazid and rifampicin.

1. Introduction. 2. Non-tuberculous mycobacteria. 3. Characteristics of Mycobacterium kansasii. 4. Epidemiology. 5. Laboratory diagnostics. 6. Pathogenesis and clinical features. 6.1. Host-pathogen interactions. 6.2. Sources of infections. 6.4. Risk factors. 6.4. Diagnosis. 6.5. Clinical picture. 7. Treatment. 8. Summary

Autor: Postępy Mikrobiologii
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Hamowanie wzrostu bakterii przez peptydowe kwasy nukleinowe i ich potencjalna rola w biotechnologii

Inhibition of bacterial translation and growth by antisense peptide nucleic acids and their potential applications in biotechnology
A. Markowska-Zagrajek, M. Równicki, J. Trylska
28 July 2017

1. Wstęp. 2. Peptydowe kwasy nukleinowe (PNA) 3. Zalety i wady PNA. 4. Sposoby transportu PNA do komórek bakteryjnych. 5. Inhibicja wzrostu bakterii poprzez wiązanie się z bakteryjnym mRNA. 6. Inhibicja wzrostu bakterii poprzez wiązanie się z bakteryjnym rRNA. 7. Zastosowanie PNA w biotechnologii. 8. Podsumowanie

Abstract: The broad use of antibiotics has resulted in the survival and spread of resistant bacterial strains. Bacteria can effectively acquire resistance when exposed to antibiotics. Therefore, it is crucial to find new antimicrobial drugs to combat antibiotic-resistant pathogens. Antisense technology involving targeting or modifying gene expression in a sequence-dependent manner has been applied to distinguish bacterial species, design antibacterials or in diagnostic applications. Typically, the bacterial target is either DNA or mRNA but there exist examples of bacterial ribosomal RNA targets. Natural oligonucleotides are unstable so in the antisense applications most often their modified versions are used. Synthetic nucleic acid analogues include locked nucleic acids, peptide nucleic acids (PNAs), and phosphorodiamidate morpholino oligomers. We will focus on the applications of PNAs, which are neutral DNA analogues containing
a pseudo-peptide backbone instead of a charged phosphate one. PNA oligomers are not degraded by proteases and nucleases. Furthermore, PNAs are not recognized by RNases. PNA oligomers can efficiently hybridize with DNA or RNA strands, and form stable duplexes or triplexes. Here, we review the studies on the development of antisense PNA sequences targeting bacterial mRNAs and rRNAs. In addition, the future prospects on the use of PNA in biotechnology are discussed.

1. Introduction. 2. Peptide nucleic acids (PNAs). 3. Advantages and disadvantages of PNA. 4. Transport of PNA into bacterial cells. 5. Inhibition of bacterial growth by targeting bacterial mRNA. 6. Inhibition of bacterial growth by targeting bacterial rRNA. 7. The use of PNA in biotechnology. 8. Summary

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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Rola mitochondriów w odporności przeciwwirusowej

The role of mitochondria in antiviral immunity
K. P. Gregorczyk, Z. Wyżewski, L. Szulc-Dąbrowska, J. Struzik, J. Szczepanowska, M. Niemiałtowski
28 July 2017

1. Wstęp. 2. Udział mitochondriów w produkcji IFN typu I oraz cytokin prozapalnych. 3. Wirusowe mechanizmy hamowania zależnej od mitochondriów produkcji IFN typu I oraz cytokin prozapalnych. 4. Apoptoza – proces „pseudoprzeciwwirusowy”. 5. Podsumowanie

Abstract: Mitochondria, which are known as “powerhouse” of the cell, have numerous important functions in cellular metabolism and are involved in cellular innate antiviral immunity in vertebrates. They participate in an intrinsic pathway of apoptosis and production of proinflammatory cytokines and type I interferons (IFNs; α/β). These functions are essential for limiting the spread of viral infection before the stimulation of adaptive immunity. However, viruses have evolved the ability to escape from the mechanisms of immune response including those related to mitochondrial functions. Viruses can exploit these organelles in their replication cycle and/or morphogenesis process, therefore the answer to the question about the exact role of mitochondria during viral infection is not unequivocal.

1. Introduction. 2. Contribution of mitochondria in type I IFN and pro-inflammatory cytokines production. 3. Viral inhibition mechanisms of the mitochondrial-dependent production of type I IFN and pro-inflammatory cytokines. 4. Apoptosis – “pseudoantiviral” process. 5. Summary

Autor: Postępy Mikrobiologii
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Kultury starterowe do produkcji twarogów kwasowych – rola i oczekiwania

Starter cultures for acid curd – role and expectations
J. Żylińska, K. Siemianowski, K. Bohdziewicz, K. Pawlikowska, P. Kołakowski, J. Szpendowski, J. Bardowski
28 July 2017

1. Wstęp. 2. Technologia twarogów kwasowych. 3. Rola kultur starterowych w produkcji serów twarogowych. 4. Kultury starterowe w produkcji twarogu kwasowego. 4.1. Oporność na bakteriofagi. 4.2. Produkcja bakteriocyn. 4.3. Aktywność proteolityczna i lipolityczna. 4.4. Produkcja zewnątrzkomórkowych polisacharydów. 5. Podsumowanie

Abstract: Lactic acid bacteria are industrially important microbes used all over the world in a large variety of industrial food fermentations. Cheese, cottage cheese, especially acid curd cheese, are characteristic dairy products for some Central and Eastern European countries. For production of acid curd cheese, only two components are needed: milk and lactic acid bacteria starter cultures. Starter cultures determine in large extent the technological process, the quality of the resulting quark and its shelf life. The composition of quark acid bacteria cultures is constituted in majority by Lactococcus and Leuconostoc bacteria. Selection of strains and construction of cultures with balanced species and stable composition for acid curd production is still very complex and presents a difficult challenge for producers of dairy cultures.

1. Introduction. 2. Acid curd technology. 3. The role of starter cultures in the production of cottage cheese. 4. Starter cultures for acid curd. 4.1. Bacteriophage resistance. 4.2. Bacteriocin production 4.3. Proteolytic and lipolytic activity. 4.4. Production of extracellular polysaccharides. 5. Summary

Autor: Postępy Mikrobiologii
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Advancements of Microbiology
Volume 63 (2024): Issue 1

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PTM

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