All posts by Postępy Mikrobiologii

Oporność bakterii z rodziny Enterobacteriaceae na antybiotyki β-laktamowe wynikająca z wytwarzania β-laktamaz

β-Lactamase-mediated resistance in Enterobacteriaceae
E. Nikonorow, A. Baraniak, M. Gniadkowski
4 October 2017

1. Wprowadzenie. 2. Mechanizmy oporności bakterii na antybiotyki β-laktamowe. 3. Klasyfikacja β-laktamaz. 4. β-Laktamazy gatunkowo-specyficzne. 5. β-Laktamazy nabyte. 6. Ekspresja β-laktamaz. 7. Najważniejsze grupy β-laktamaz nabytych. 7.1. β-Laktamazy o rozszerzonym spektrum substratowym, ESBL. 7.2. Cefalosporynazy AmpC. 7.3. Karbapenemazy. 7.3.1. Karbapenemazy klasy A 7.3.2. Karbapenemazy klasy B. 7.3.3. Karbapenemazy klasy D. 8. Podsumowanie

Abstract: Production is β-Lactamase the major mechanism of resistance to β-lactams in Gram-negative bacteria. In recent years, resistance due to production of β-lactamases has been increasing at on alarming rate. It refers mostly to extended-spectrum β-lactamases (ESBLs) that are the main problem in microorganisms of the family Enterobacteriaceae, conferring resistance to all penicillins, cephalosporins (except for cephamycins) and monobactams. Acquired cephalosporinases of the AmpC type also have become a significant factor of enterobacterial resistance to newer generation of β-lactams. The effect of AmpCs is largely strengthened by this mutational overexpression in such pathogens as Enterobacter spp. or Citrobacter freundii. β-Lactamase-mediated resistance to carbapenems in the members of the family Enterobacteriaceae has become a matter of highest concern over the last decade. It has been associated with various carbapenemhydrolyzing enzymes, including the so-called KPC, MBL or OXA-48 types. Antimicrobial resistance in bacteria has been a key issue in public health, requiring constant monitoring at the hospital, country and global level.

1. Introduction. 2. Mechanisms of resistance to β-lactam antibiotics. 3. Classification of β-lactamases. 4. Natural β-lactamases. 5. Acquired β-lactamases. 6. Expression of β-lactamases. 7. Main groups of the acquired β-lactamases. 7.1. Extended-spectrum β-lactamases, ESBLs. 7.2. AmpC-type cephalosporinases. 7.3. Carbapenemases. 7.3.1. Class A carbapenemases. 7.3.2. Class  B
carbapenemases. 7.3.3. Class D carbapenemases. 8. Conclusions

Autor: Postępy Mikrobiologii
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Immunoprofilaktyka zakażeń Campylobacter

Anti-Campylobacter immunoprophylaxis
P. Łaniewski, E. K. Jagusztyn - Krynicka
4 October 2017

1. Charakterystyka patogenu i epidemiologia zakażeń. 2. Objawy chorobowe i źródła zakażeń. 3. Szczepionki anty-Campylobacter. 4. Podjednostkowe szczepionki anty-Campylobacter skonstruowane z użyciem atenuowanych szczepów S.enterica. 5. Podsumowanie

Abstract: Campylobacter jejuni is currently recognized as a major cause of food-borne human gastroenteritis worldwide. In developed countries the majority of Campylobacter infections are associated with the consumption of undercooked poultry meat. Although a  disease lasts only several days and is very often self-limiting, campylobacteriosis constitutes a serious medical and socioeconomic problem. In patients, especially from developed countries, who have not encountered the pathogen before the infection can result in severe gastroenteritis accompanied with long-lasting bloody or mucus diarrhea. Moreover, C. jejuni can cause septicemia in immunocompromised individuals or induce autoimmune neurological disorders. Rapidly increasing antibiotic resistance of Campylobacter strains compels us to develop alternative therapeutic strategies. Implementation of immunoprophylaxis for humans or chickens seems to be the most effective strategy to decrease the number of human infections. Subunit vaccines are the safest, but mildly immunogenic, prophylactic method therefore, heterologous antigens are frequently delivered to a host by special delivery vectors i.e. attenuated Salmonella strains, to induce protective immune response. Avirulent Salmonella strains were also successfully used as a carrier to construct anti-Campylobacter subunit vaccines. Up till now, only several Campylobacter genes encoding immunogenic proteins: Peb1A, CjaA, Pal, Cj0420 and bacterioferritin, were cloned in Salmonella cells and the immune response and protection efficiency of constructed vaccine were determined on animal models. Here, we discuss the recent developments in the field of Salmonella-based anti-Campylobacter vaccines.

1. Pathogen characteristics and infection epidemiology. 2. The symptoms and source of infections. 3. Anti-Campylobacter vaccines. 4. Anti-Campylobacter subunit vaccines constructed with attenuated S.enterica cells. 5. Conclusions

Autor: Postępy Mikrobiologii
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Konstrukcja szczepionek podjednostkowych z wykorzystaniem komórek Salmonella enterica jako nośnika heterologicznych genów

Subunit vaccine construction using Salmonella enterica cells as a carrier of heterologous genes
P. Łaniewski, E. K. Jagusztyn - Krynicka
4 October 2017

1. Salmonella jako idealny nośnik heterologicznych antygenów. 2. Atenuacja komórek S.enterica. 3. Stabilność utrzymania transgenu. 4. Poziom ekspresji transgenu. 5. Lokalizacja antygenu a typ odpowiedzi immunologicznej. 6. Podsumowanie

Abstract: Salmonella enterica strains are widely employed as a live delivery vector for subunit vaccine construction. Vaccine strains must be safe but still immunogenic; therefore, it is crucial to obtain a proper balance between the attenuation and the reactogenicity of the constructed strains. Salmonella strains used in immunoprophylaxis are mainly constitutively disrupted in genes involved in auxotrophy, virulence or regulation. A novel promising concept of the Salmonella-based vaccine design is a regulated delayed attenuation in vivo combined with a delayed antigen expression system. Using this approach bacteria display features of a wild-type strain at the time of oral vaccination to effectively colonize the lymphoid tissue and the fully attenuated phenotype after host tissue colonization. Expression of heterelogous genes in Salmonella cells is mainly achieved by introducing recombinant plasmids harboring gene of interest. Alternatively, a transgene can be integrated into a chromosomal DNA. Diverse strategies were developed to control plasmid maintenance and foreign gene expression. Among them the most frequently used are the balanced-lethal and toxin-antidote systems or operator-repressor titration technology. Overproduction of a recombinant protein often causes a metabolic burden in vaccine cells resulting in the loss of their viability. To overwhelm the problem, the transgene expression is kept under control of an in vivo inducible promoter or a promoter which activity is regulated by appropriate small molecules. Alternatively, plasmids with a regulated copy number or a delayed antigen synthesis system have been employed by various research groups. Localization of an antigen in a carrier cell is also critical for the strength and type of immune response. A programmed lysis of carrier cells is used to deliver the antigen to host immune cells. Moreover, Salmonella is used to carry DNA vaccines. Here, we review the latest strategies in the design of Salmonella-based subunit vaccines.

1. Salmonella as a perfect carrier of heterologous antigens. 2. Attenuation of S.enterica cells. 3. Transgene stability. 4. Transgene expression level. 5. Antigen localization and the type of immune response. 6. Conclusions

Autor: Postępy Mikrobiologii
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Charakterystyka grzybów z rodzaju Malassezia. I. Aspekty mikrobiologiczne i immunologiczne

Characterization of fungi of the Malassezia genus. I. Microbiological and immunological aspects
T. Jagielski, E. Rup, A. B. Macura, J. Bielecki
4 October 2017

1. Wprowadzenie. 2..Taksonomia i klasyfikacja grzybów z rodzaju Malassezia. 3. Mikrobiologia grzybów z rodzaju Malassezia. 3.1. Charakterystyka ogólna. 3.2. Metabolizm. 3.3. Aktywność enzymatyczna. 4. Interakcje grzybów Malassezia sp. z  innymi mikroorganizmami. 5. Interakcje grzybów Malassezia sp. z układem immunologicznym. 5.1. Serologia i budowa antygenowa. 5.2. Interakcje z układem dopełniacza. 5.3. Wpływ grzybów Malassezia sp. na różne populacje komórek w skórze. 6. Podsumowanie

Abstract: The yeasts of the Malassezia genus, first described over a century ago, belong to the physiological microflora of the human skin. However, they may occasionally act as opportunistic pathogens resulting in different dermatological pathologies, of which pityriasis versicolor is most frequently diagnosed. Two principle features of the genus Malassezia are distinctive morphology and requirement for external lipid source for growth. To date, the genus accommodates 14 species, all but one being lipid-dependent species. The very recently completed sequencing of the M. globosa genome disclosed the presence of multiple secreted lipases to help the yeasts to utilize cutaneous lipids. Very little is known about interactions between Malassezia organisms and the human host. It is clear however that Malassezia fungi display two phenotypes within the skin, one – immunostimulatory, and the other immunosuppressive, which are responsible for commensal and pathogenic behavior of the fungi, respectively.
This article provides a concise and up-to-date description of the Malassezia genus, with particular attention to the microbiology of the fungi and their interactions with the immune system of the human host.

1. Introduction. 2. Taxonomy and classification of Malassezia fungi. 3. Microbiology of Malassezia fungi. 3.1. General characteristics. 3.2. Metabolism. 3.3. Enzymatic activity. 4. Interactions of Malassezia fungi with oher microorganisms. 5. Interactions of Malassezia fungi with the immune system. 5.1. Serology and antigenic structure. 5.2. Interactions with the complement system.
5.3. Influence of Malassezia fungi on different cel populations within the skin. 6. Conclusions

Autor: Postępy Mikrobiologii
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Charakterystyka grzybów z rodzaju Malassezia. II. Aspekty kliniczne

Characterization of fungi of the Malassezia genus. II. Clinical aspects
E. Rup, T. Jagielski, A. Macura, J. Bielecki
4 October 2017

1. Występowanie i chorobotwórczość grzybów z rodzaju Malassezia. 1.1. Dystrybucja grzybów z rodzaju Malassezia. 1.2. Chorobotwórczość grzybów Malassezia sp. 1.2.1. Łupież pstry (Pityriasis versicolor, PV). 1.2.2. Zapalenie mieszków włosowych (Malassezia folliculitis). 1.2.3. Łojotokowe zapalenie skóry i łupież (Seborrhoeic dermatitis/Dandruff; SD/D). 1.2.4. Atopowe zapalenie skóry. 1.2.5. Łuszczyca. 2. Wrażliwość na leki grzybów z rodzaju Malassezia. 3. Przyszłość badań nad grzybami z rodzaju Malassezia 

Abstract: Lipophilic yeasts of the genus Malassezia have been associated with a number of diseases affecting human skin. Clinically, pityriasis versicolor is the most important, ranking the first among all cutaneous mycoses in human population worldwide. Malassezia fungi may also aggravate the symptoms of other skin disorders, such as seborrheic dermatitis or exacerbate the course of psoriasis and atopic dermatitis. This review briefly outlines the epidemiology, risk factors, pathogenesis, clinical manifestations, and treatment of various skin diseases related to the Malassezia species.

1. Prevalence and pathogenicity of Malassezia fungi. 1.1. Distribution of Malassezia fungi. 1.2. Pathogenicity of Malassezia sp. 1.2.1. Pityriasis versicolor (PV). 1.2.2. Malassezia folliculitis. 1.2.3. Seborrhoeic dermatitis/Dandruff (SD/D). 1.2.4. Atopic dermatitits. 1.2.5. Psoriasis. 2. Drug susceptibility of Malassezia fungi. 3. Future of the research on Malassezia fungi

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Advancements of Microbiology
Volume 63 (2024): Issue 1

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PTM

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