Volumen 58 (2019): Edición 4 (January 2019)

Neisseria gonorrhoeae (gonococcus) is a Gram-negative bacteria and an etiological agent of the sexually transmitted disease – gonorrhea. N. gonorrhoeae possesses many mechanism to evade the innate immune response of the human host. Most are related to serum resistance and avoidance of complement killing. However the clinical symptoms of gonorrhea are correlated with a significant presence of neutrophils, whose response is also insufficient and modulated by gonococci.

1. Introduction. 2. Adherence ability. 3. Serum resistance and complement system. 4. Neutrophils. 4.1. Phagocytosis. 4.1.1. Oxygen-dependent intracellular killing. 4.1.2. Oxygen-independent intracellular killing. 4.2. Neutrophil extracellular traps. 4.3. Degranulation. 4.4. Apoptosis. 5. Summary

The edaphic factors are the soil properties that affect the diversity of organisms living in the soil environment. These include soil structure, temperature, pH, and salinity. Some of them are influenced by man, but most are independent of human activity. These factors influence the species composition of soil microbial communities, but also their activity and functionality. The correlations between different abiotic factors and microbial groups described in this manuscript indicate both the complexity of the soil environment and its sensitivity to various stimuli.

1. Introduction. 2. Soil type and structure. 3. Soil pH and salinity. 4. Soil temperature. 5. Soil moisture. 6. Organic carbon and nitrogen content. 7. Heavy metals content. 8. Conclusions

Campylobacter jejuni/coli is the leading bacterial cause of diarrhoea in humans in both developing and developed countries. Epidemiological studies show that most cases of campylobacteriosis are the result of the consumption of undercooked, contaminated poultry meat. Although campylobacteriosis is largely a self-limiting disease with low mortality, a specific treatment is required for patients infected with strains resistant to clinically important antibiotics and for patients who develop neurological symptoms or bacteremia in course of infection. Despite intensive efforts to improve an on-farm biosecurity practice over the past decade, about 70% of EU broiler chicken flocks remain Campylobacter-positive at slaughter. Control of spreading the Campylobacter infection in flocks of chickens by biosecurity actions turned out rather ineffective. The most efficient strategy to decrease the number of human Campylobacter infections may be to implement an immunoprophylactic method, namely, the protective vaccination of chickens. The publication presents the current state of knowledge on anti-Campylobacter immunoprophylaxis in poultry.

1. Campylobacteriosis – epidemiological data, disease symptoms. 2. Campylobacteriosis – source of infection. 3. Campylobacteriosis – prophylaxis. 4. Immunization of chicken. 4.1. Passive immunization. 4.2, Campylobacter Whole-cell Vaccines. 4.3. Subunit vaccines. 5. Strategies for developing modern subunit vaccines. 5.1 Searching for antigen. 5.2. The choice of a carrier. 6. Modulation of immune response. 7. The route of antigen administration. 8. Summary

Lyme borreliosis, an infectious disease caused by tick-borne spirochetes of the Borrelia burgdorferi sensu lato complex, is regarded as the most commonly reported vector-borne infection in the Northern Hemisphere. Currently, the basis for laboratory diagnosis of Lyme disease is a two-step serological examination. The first is an enzyme-linked immunosorbent assay (ELISA). If the test result is positive or questionable, a Western blot is used as the second phase test. In both methods, the total cell lysates of B. burgdorferi s.l. are used as the main source of antigens. However, the huge diversity of genospecies within B. burgdorferi s.l. and the low degree of preservation of the sequence of their proteins means that using the cell lysates of one of the species is not sufficient to correctly diagnose Lyme disease. Numerous literature reports show that the use of B. burgdorferi s.l. recombinant or chimeric antigens may be a potential solution to problems occurring in Lyme disease immunodiagnosis. However, for diagnostic tests based on recombinant proteins to be as effective as possible, carefully selected antigens or fragments should be used. With this approach, a test can be developed with a sensitivity that remains independent of the B. burgdorferi s.l. species which caused the disease. In addition, the exclusive use of protein fragments may definitely reduce the frequency of cross-reactions.

1. Introduction. 2. Characterization of selected B. burgdorferi s.l. antigens. 3. Diagnosis of Lyme disease. 4. Problems in Lyme disease serodiagnosis. 5. Use of recombinant antigens and synthetic peptides in the diagnosis of Lyme disease. 6. Summary

Iron is one of the most important micronutrients used by bacteria, essential for their basic metabolism. Over 70% of bioavailable iron in mammals is in the heme molecule. Gram-negative pathogenic bacteria during colonization and infection of the host organism use heme as the main source of iron. Bacteria have developed two types of outer membrane receptors/transporters involved in the heme uptake. The first one focuses on the receptors recognizing heme or hemoproteins and transporting the ligand through the outer membrane. The second type of receptor recognizes and takes up heme in a complex with a hemophore, a small protein released from a bacterial cell. Microorganisms have developed appropriate transcriptional and post-transcriptional mechanisms that control the iron/ heme uptake, protecting against their toxic excess. One of the most important regulatory systems is based on the functioning of the Fur protein, a repressor of gene transcription. More and more is known about the role of non-coding RNAs in post-transcriptional regulation of Fur regulon gene expression.

1. Introduction. 2. Hem and heme compounds in the host organism. 3. Binding and transport of heme through bacterial wall and membranes. 3.1. Active transport of heme through the outer membrane of Gram-negative bacteria. 3.2. ATP-dependent transport across the cytoplasmic membrane. 4. Regulation of gene expression of heme uptake. 4.1. Characteristics of Fur protein. 4.2. Fur-DNA interaction. 4.3. Regulation of fur gene expression in E. coli. 4.4. Fur as a global regulator of gene expression in E. coli. 4.5. Other mechanisms for controlling the expression of heme uptake genes. 5. Summary

According to the World Health Organization (WHO), the widespread problem of overweight and obesity is the fifth most important risk factor for deaths in the world. The most frequently mentioned are the genetic and environmental factors that lead to the absorption of excess energy from food and to accumulate it in the form of spare adipose tissue. Another important fact is that even the use of a low-energy diet does not support the effective reduction of excessive body weight. It turns out that the cause may be intestinal microbiota, the composition of which changes in people with overweight and obesity. The intestinal microbiota dysbiosis is additionally perceived by many researchers as the cause of the development of metabolic diseases, including obesity or type 2 diabetes. On the other hand, Gram-negative bacteria constituting a component of the intestinal ecosystem are the source of lipopolysaccharide (LPS), responsible for the development of systemic inflammation and endotoxemia. Based on a literature review related to the subject, it can be concluded that intestinal microbiota disorders, intestinal barrier damage and increased LPS levels in patients adversely affect the obesity and components of the metabolic syndrome and hinder the treatment of these diseases.

1. Introduction. 2. Intestinal barrier function. 3. Intestinal barrier disorders and endotoxemia. 4. Summary

Multi-resistant bacterial strains currently present the main health problem worldwide. Numerous public health organizations call for the prevention, and control the spread, of antibiotic resistance from any sources. From the literature data, it is well known that agricultural areas are a source of antibiotic resistance because of the use of antibiotics and heavy metals to promote plant and animal growth. Moreover, natural water reservoirs and soil not used for agriculture are also sources of multi-drug resistant bacteria. In recent years bacteria resistant to antibiotics and heavy metals have been isolated from heavy-metal contaminated soils and from metallophytes. Therefore, it seems that heavy metals, an environmental pollutant, may also be a selection factor that promotes the spread of antibiotic resistance. The co-selection phenomenon of resistant genes is most often connected with the lack of bacterial susceptibility to antibiotics and heavy metals. Co-selection occurs when different resistant genes that enable resistance to different stress conditions are located on the same mobile genetic elements, or when the same genes determine resistance to different stress conditions. This article presents the current state of knowledge about the co-selection phenomenon observed in bacteria isolated from nonclinical environments.

1. Introduction. 2. Co-selection mechanisms. 2.1. Cross-resistance. 2.2. Co-resistance. 2.3. Co-regulation. 3. Factors promoting spread of co-selection. 4. Occurrence of co-selection in non-clinical environments. 4.1. Areas used for agriculture. 4.2. Areas not used agriculturally. 4.3. Natural water reservoirs. 4.4. Plant endosphere. 5. Co-occurence of resistant genes in different environmental genomes. 6. Summary

Extremophilic viruses inhabit even the most extreme environments, such as underwater and terrestrial hydrothermal vents, deserts, subpolar areas, deep subsurface sediments, hypersaline environments, and alkaline lakes. These are mainly viruses that infect bacteria (belonging to the Myoviridae and Siphoviridae families) and archaea (classified to the families Lipothrixviridae, Rudiviridae, Yueviridae, Ampullaviridae, Globuloviridae, Sphaerolipoviridae, Bicaudaviridae, Fuselloviridae, Guttaviridae, Clavaviridae, and Turriviridae), some of which have not been fully classified. Extremoviruses have genetic material mainly in the form of dsDNA, both circular and linear, whose average length varies between 14 and 80kbp and is optimal because it is not degraded by high or low temperature, salt solutions or elevated pressure, and encodes all features necessary to function in extreme conditions. This also confirms the much higher resistance of DNA to external factors compared to delicate RNA. Further studies on extremophilic viruses can lead to full sequencing of their genomes, recognition of genes determining resistance traits to unfavorable environmental conditions, and a closer understanding of the full history of the evolution of organisms on Earth.

1. Introduction. 2. Viruses of extremely high temperatures. 2.1. Viruses of hot terrestrial springs. 2.2. Viruses of deep-sea hydrothermal vents. 3. Viruses of deserts. 4. Viruses of subpolar areas. 5. Viruses of subsurface sediments. 6. Viruses of hypersaline areas. 6.1. Viruses of freshwater lakes. 6.2 Viruses of alkaline lakes. 7. Conclusions

A killer phenotype, associated with the production and secretion of killer toxins, is widespread among yeasts and in competitive conditions gives an advantage to killer yeast strains in relation to other, sensitive microorganisms colonizing the same ecological niche. Killer toxins are proteins, usually glycoproteins, that are able to kill strains of susceptible yeasts. Each killer toxin has unique properties that vary depending on the strain of yeast that produces it. These differences concern the location of genes that encode toxins, molecular weight, as well as mechanisms of action. Some strains of killer yeast are characterized by a wide range of antagonistic activity, inhibit the development of a number of yeast strains, as well as molds, and have been studied for many years in terms of their biotechnological potential. Killer yeast and its toxins can find potential application in many fields: in the production of food and beverages, especially during wine fermentation and maturation, in biological control of plant pathogens, in yeast biotyping and as new antifungal agents.

1. Introduction. 2. Biosynthesis and structure of killer toxins. 3. Properties of killer proteins. 4. The mechanism of action of killer toxins. 5. Use of killer yeasts and their toxins. 5.1. Application in viticulture. 5.2. Potential application in medicine. 5.3. Combating fungal diseases of plants. 5.4. Transgenic plants producing killer toxins. 5.5. Use of killer yeasts in the marine environment. 6. Summary

Naturally occurring entomopathogens are important regulatory factors of insect populations. Among them, entomopathogenic fungi play a meaningful role. The invasion of insects by parasitic fungi occurs through penetration of the host integument. Death of the host is a result of tissue destruction, exhaustion of nutrients, and the production of toxins. Many recent studies show that entomopathogenic fungi are not only considered as insect pathogens, but also play additional roles in nature, including endophytism, plant disease antagonism, plant growth promotion, and rhizosphere colonization. These newly understood attributes provide possibilities to use fungi in multiple roles. Such additional roles recently-discovered to be played by entomopathogenic fungi provide opportunities for multiple uses of these fungi in integrated pest management strategies. This article reviews the literature currently available on entomopathogenic fungi. It also addresses the possible mechanisms of protection conferred by endophytic fungal entomopathogens and explores the potential use of these fungi as dual microbial control agents against both insect and pathogen pests.

Introduction. 2. Historical and taxonomical notes. 3. Ecological aspects. 4. Use of entomopathogenic fungi. 5. Prospects in integrated pest management. 6. Conclusions

Fungal infections of the skin, hairs, and nails undeniably dominate among all types of fungal infections. The etiological factors of the majority of superficial fungal infections are dermatophytes which, although they are the oldest microorganisms considered as pathogens, have long been unstable in the taxonomic position. From a diagnostic point of view, the species identification of dermatophytes is still a serious problem, often generating therapeutic errors. An increasing number of infections, including zoonoses, lack of taxonomic stability and ambiguous clinical picture of all cases of dermatomycosis induce to search for new, fast, repeatable and at the same time cheap methods of species identification of these fungi. In the last decade, revolutionary progress has been observed in the development of molecular methods for the diagnosis of fungal infections and the reliable identification of species of etiological factors that cause these dermatomycoses. The results of many studies indicate that the direct identification of fungi from dermatological samples based on molecular methods is much more reliable and much faster compared to that carried out by conventional methods. Often, the etiological factor of the observed changes was also identified, while the result of cultivation was negative. Particular molecular methods used in the species identification of fungi directly from the clinical material differ in the procedures of genomic DNA extraction, PCR techniques used, the molecular marker used and the results interpretation system. This paper reviews literature regarding different methods of diagnosing of superficial fungal infections based on molecular biology techniques, their advantages and limitations, as well as critical factors for their implementation for routine use. The position of microbiologists in this matter seems to be a foregone conclusion, the time when molecular diagnostics will replace the conventional techniques, based on the cultivation of dermatophytes and assessing their morphology, inexorably coming. Molecular methods of identifying aetiological factors of dermatomycoses directly from dermatological samples are much more attractive and have many advantages.

1. Introduction. 2. Importance of identification of dermatophyte species in dermatological samples. 3. Molecular species identification in pure dermatophyte cultures. 4. Methods for direct identification of fungi from clinical samples. 4.1. DNA isolation. 4.2. Classical PCRbased techniques of direct identification. 4.3. Real-time PCR-based techniques of direct identification. 5. Choice of an optimal method for routine use. 6. Advantages and drawbacks of molecular identification methods applied in mycology. 7. Summary