Postepy Mikrobiologii

Online ISSN: 0079-4252
Publications
Article
Appropriate decontamination of hospital textiles depends heavily on specif ically def ined proceedings for handling decontaminated hospital textiles (collection, segregation, packing, transportation) and appropriate disinfection in the laundry process. It is becoming increasingly common to disinfect hospital textiles in a chemical-thermal process. Disinfectants used in this process should be applied according to functional parameters defined in validated and repeatable test methods. Changes in assessing the activity of agents used in chemical-thermal disinfection of hospital textiles refer primarily to the standardization of testing methods for these agents. PN-EN 16616 Standard which regards chemical-thermal disinfection of textiles clearly regulates the rules of assessing the effectiveness of agents used in the disinfection of hospital textiles and defines a possible scope of their biocidal activity (bactericidal, tuberculocidal and fungicidal activity). It is assumed that further assessment of the activity of sporicidal agents will be developed in the future.
 
Article
It is the 21(st) century, we are young, both world wars and people who lived then belong to the history. Sonic of us have heard about professor Weigl, however not much beyond mere facts: born in 1883, a brilliant scientist in many fields: zoology, parasitology, anatomy, histology, entomology and microbiology, inventor of the first effective vaccine against epidemic typhus (spotted fever) caused by Rickettsia. During the Second World War professor Weigl was the head of Typhoid Institute organized by the Nazis. Apart from saving people by making them workers of the Institute, lie rescued many lives illegally distributing his vaccine to the occupied areas. He received many honors for his research. Professor Weigl was not only an excellent scientist but also a great patriot and a lot of people owe their lives to him. For us lie is a role model and an authority. Despite the hard times, lie did not care for fame and money. He just wanted to create something new in science and to be a good man. Charles Nicolle said: "Weigl has saved the lives of thousands of people. He is the man who deserves the highest praise".
 
Article
Tuberculosis represents a serious problem for public health worldwide. The attenuated Mycobacterium bovis Bacille Calmette-Guérin (BCG) are widely used as tuberculosis vaccine for newborns. BCG prevents severe forms of childhood tuberculosis only and is unable to prevent pulmonary disease in adolescents and adults. Thus, a novel vaccine against tuberculosis is urgently needed. During the last years, great progress has been made in immunology, genetics and animal models of M. tuberculosis infections. Accordingly, several new vaccine candidates have been developed, many of which have entered clinical trials.
 
Article
Enterovirus 71 (EV71) is one of the most important causes of hand, foot, and mouth disease. It can also cause severe complications of the central nervous system. Brain stem encephalitis with pulmonary edema is a severe complication that can lead to death. EV71 was first isolated in California in 1969. Since the late 1990s, EV71 has seriously affected the Asia-Pacific region. In recent years, there have been an increasing number of reports of HFMD outbreaks with fatal cases due to EV71 in Asian countries. Generally, EV-71 is divided into three broad genotypes: A, B and C, based on analysis of complete genome sequences of many strains. Recent studies suggest that recombination has played a crucial role in EV71 evolution. Poliovirus, another enterovirus, is nearly completely eradicated as a result of global immunization efforts. EV71 may become an important pathogen, replacing poliovirus, with increasing health threat to humans. Prevention of EV71 epidemics is likely to require the development of an effective vaccine. This is an important public health problem causing serious clinical illness and, potentially, death in young children.
 
Article
Free living, cosmopolitan amoebae of the genus Acanthamoeba present a serious risk to human health. As facultative human parasites, these amoebae may cause health and life-threatening diseases, such as Acanthamoeba keratitis (AK), granulomatous amoebic encephalitis (GAE) and cutaneous acanthamebiasis. AK is a severe, vision-threatening cornea infection with non-specific symptoms and course. GAE is a unique central nervous system disease, almost always leading to death. Cutaneous acanthamebiasis is most common in patients with AIDS. The pathogenesis and pathophysiology of the diseases is still incompletely understood, therefore no definitive effective therapy is currently available. Prevention is very difficult due to Acanthamoeba ubiquity and resistance. Further studies on effective solutions for the prevention and treatment of Acanthamoeba infections are needed.
 
Article
The year 2010 marks the 100th anniversary of Robert Koch's death. Heinrich Herman Robert Koch, born December 11, 1843 in Clausthal, died May 27, 1910 in Baden-Baden, was a German medical bacteriologist, physician, one of the founders of the science of bacteriology, who discovered the tubercle bacillus (1882) and cholera bacillus (1883). He won the Nobel Prize for Physiology and medicine in 1905. Koch developed new techniques and adapted old techniques to new uses. With his students, he created the majority of techniques for the modern study of bacteria. Koch established the new fields of medical bacteriology, public health and hygiene. Koch's great contribution to the development of bacteriology was his introduction of pure culture technique using solid and semi solid media. This technology led to the isolation and characterization of microorganisms causing many bacterial diseases which affected humans.
 
Article
In all bacteria fatty acids are found as a major component of their membrane lipids. The well-known spectrum of bacterial fatty acids comprises saturated, cis, trans-monounsaturated, diunsaturated, cyclopropane, hydroxyl and methyl-branched fatty acids. Recently a new type has been found as membrane constituents - polyunsaturated fatty acids. The physical properties of bacterial membranes are determined by the composition of fatty acids. Some membrane active agents, including aromatic compounds, have a strong influence on membrane fluidity. These compounds dissolve in the cell membrane disturbing its integrity and affecting specific permeabilization. The hydrophobicity of an aromatic compound, expressed as its logP value, is a good indicator of its toxicity. Microorganisms however can adapt to many organic compounds by changing of their membrane fluidity. They can modify degree of saturation of fatty acids, the average chain length and the protein content. This mechanism is called "homeoviscosic adaptation". One of the key processes in the adaptation of some Pseudomonas, Vibrio and Escherichia coli strains, enabling them to tolerate aromatic compounds, appears to be the isomerization of cis - into trans-unsaturated fatty acids. The analysis of microbial membrane lipids, specifically phospholipid fatty acids (PLFA) is a powerful tool for monitoring the microbial responses to changes in their environment. Phospholipids are extracted directly from environmental samples to characterise microorganisms within their communities. Microbial PLFA analysis provides quantitative insight into three important attributes of microbial communities, viable biomass, community structure and metabolic activity. Certain pollutants induce changes in some PLFA components such as ratio of saturated to unsaturated fatty acids, ratio of trans to cis-monoenoic unsaturated fatty acids, and the content of cyclopropane fatty acids. It might function as an indicator for the toxicity of many aromatic pollutants, particularly during in situ bioremediation and biotransformation processes.
 
Article
In recent years Acinetobacter spp. have emerged as important nosocomial pathogens which are known to express a variety of resistance mechanisms. They do not posses any important virulence factors. The danger of these agents resides in their capability to acquire and develop resistance to multiple classes of useful antibiotics to the extent that it could be considered as a significant virulence factor. In this way, they can adapt to new environmental conditions. It is important to know the mechanisms of resistance to non-β-lactam antibiotics because some of Acinetobacter spp. exhibit resistance to all β-lactams, including carbapenems, and reduced susceptibility to polymyxins. Apart from β-lactams, aminoglycosides fluoroquinolones and tetracyclines are widely used for treating Acinetobacter spp. infections. Acinetobacter spp. resistance to aminoglycosides results from the production of aminoglycoside-modifying enzymes such as acetyltransferases (AAC), nucleotidyltransferases (ANT, AAD) and phosphotransferases (APH). Resistance to fluoroquinolones has been linked to mutations in the quinolone-resistance- determining-region (QRDR) of gyrA, parC genes and a decrease in quinolone accumulation due to the decreased uptake or increased efflux. The main mechanisms responsible for tetracycline resistance have been identified as the expression of efflux pumps tet(A), tet(B) and ribosomal protection (tetM). Combination therapy is used to widen the antymicrobial spectrum, minimize toxicity and prevent the emergence of resistant mutants.
 
Article
Acinetobacter spp., particularly A. baumannii, are opportunistic microorganisms, causing infections most often in patients undergoing intensive therapy and in immunocompromised individuals. In the recent years, their clinical significance has been increasing. Due to the wide distribution of Acinetobacter spp. rods in the environment, as well as their ability to survive in different conditions, they may cause extensive and prolonged difficulties in to controling the epidemic outbreaks in healthcare institutions. Molecular techniques used for typing of bacterial isolates confirm their spread and show their ability to cause recurrent epidemics even several months after the first outbreak. To date, three epidemic clones of A. baumannii have been identified in Europe. Recently, it has been reported that isolates genetically identical to the European clone I and II are circulating in Poland. Bacteria of the genus Acinetobacter are characterised by natural resistance to many antibacterial agents. They also easily acquire genes conferring resistance to other groups of antimicrobials, including carbapenems. Recently, the presence of a gene encoding metallo-β-lactamase type VIM has been detected in carbapenem-resistant clinical strains of Acinetobacter baumannii isolated in Warsaw. This was the first report in Poland, while the presence of VIM enzymes in A. baumannii has been reported so far only in South Korea, Spain and Greece. Detection of bla VIM gene in A. baumannii strains belonging to the European clone II, with the increased potential for epidemic spread, indicates the need to take effective measures which would prevent the spread of infections and would limit the selection of multidrug-resistant strains. Formation of a biofilm by microorganisms is now increasingly recognized as their virulence factor contributing to the pathogenesis of infections. It is estimated that over 60% of all bacterial infections are caused by biofilms, including infections derived from the use of medical devices, such as central and peripheral vascular catheters, urinary catheters or implants. A wide variation in biofilm formation was detected among the clinical strains of A. baumannii.
 
Article
The genomic species is one of the major concepts of a bacterial species and is based on quantitative similarities between chromosomal DNAs of bacteria (DNA reassociation values) as determined by DNA-DNA hybridization. This method is one of the recommended standards for delineating bacterial species and a genomic species is defined as a group of bacterial strains that have DNA-DNA reassociation values of approximately 70% or more. The similarity of small subunit rRNA (16S rRNA) sequences is increasingly being used for the classification of bacteria. However, the resolution of 16S rRNA sequence analysis is insufficient to distinguish closely related genomic species because of the extremely slow rate of base substitiution in 16S rDNAs. On the other hand, phylogenetic analysis based on protein-encoding genes provides a greater degree of resolution than that based on 16S rRNA genes since the former genes evolve faster than the latter. Various protein--Encoding genes such as recA, groEL, hsp75, rpoB, rpoD and gyrB have been used for the classification of bacteria at the intragenic level. It has been reported that the grouping of Acinetobacter strains based on 16S rRNA sequence analysis, DNA-DNA hybridization analysis and phenotypic methods is inconsistent and therefore the establishment of reliable methods for unambiguous identification of these strains is quite urgent. We are interested in examining the possibility that phylogenetic analysis using protein-encoding recA genes could be used for the identification of Acinetobacter strains and to provide information equivalent to that of DNA-DNA hybridization analysis.
 
Article
Members of the genus Acinetobacter are Gram-negative bacteria that are widely distributed in nature and can be isolated from soil, water, and human skin. Some of the genospecies are commonly found in the hospital environment and are capable or causing a wide range of nosocomial opportunistic infections, whilst others have not been linked to human disease. The taxonomy of the genus Acinetobacter has changed extensively during the past decade and at present comprises at least 22 genospecies, seven of which have been formal species names whilst the others are designated by numbers. Six of the genospecies (A. calcoaceticus, A. baumannii, genospecies 3, "between 1 and 3", 13, and "close to 13") are very similar phenotypically, and are known collectively as the Acinetobacter calcoaceticus-Acinetobacter baumannii (Acb) complex, even though they are genetically distinct. Identification of Acinetobacter spp. To the genospecies level using phenotypic techniques is not reliable. Given the medical importance of some of the genospecies, there is a need for alternative methods that can be applied to large numbers of stains for epidemiological studies. The delineation of the genospecies is based on DNA-DNA hybridisation grouping but this procedure is laborious and unsuitable for use in routine microbiology laboratories. Over the past few years, various molecular techniques have been employed for the genotype and epidemiology analysis of the genus Acinetobacter, including plasmid profile analysis, RFLP/PFGE, PCR fingerprinting, amplified ribosomal DNA restriction analysis (ARDRA), analysis of amplified 16S to 23S ribosomal DNA intergenic spacer regions, restriction analysis of amplified recA gene sequences, a multiplex PCR assay that simultaneously targets RecA- and 16S rRNA- encoding genes, tRNA fingerprinting, DNA sequence analysis of genes encoding 16S rRNA or gyrase subunit B and AFLP technique.
 
Article
Acinetobacter baumannii has become one of the most dangerous Gram-negative bacterial species, causing numerous infections over the last 20 years. A. baumannii is responsible for nosocomial ventilator-associated pneumonia (VAP), urinary tract infections, meningitidis and bacteremia. Its remarkable ability to acquire resistance determinants against multiple antibiotics of different classes and to tolerate harsh environments resulted in the dissemination of multi-drug-resistant (MDR) strains. Diverse mechanisms of resistance limit therapeutic options and make the infections difficult to treat. The described resistance mechanisms include: production of beta-lactamases, i.e. enzymes modifying structure of antibiotics, activity of efflux pumps, loss of membrane porins and formation of biofilm.
 
Article
Acinetobacter spp. has emerged as a serious nosocomial pathogen in many countries mainly due to its resistance to β-lactams, which are the most frequently used antibiotics. These bacteria appears to have a propensity for developing antibiotic resistance extremely fast. Many mechanisms of resistance to β-lactams have been identified in this species. Acinetobacter spp. is responsible for the production of all classes of β-lactamases. The most important β-lactamases are cefalosporinases, which are C class β-lactamases, A class β-lactamases, OXA enzymes, which are D class β-lactamases and B class β-lactamases also known as metallo-β-lactamases. ESBL, related to the narrow spectrum TEM and SHV type β-laktamases, have not yet been detected in Acinetobacter spp. The only type of ESBL identified in this agent were non-TEM and non-SHV type ESBL: PER, VEB and CTX-M. Acinetobacter spp. all produce OXA-type β-lactamases that hydrolyze carbapenems OXA-23, OXA-24, OXA-25, OXA-26, OXA-27, OXA-40, OXA-51 and OXA-58, which have already been identified and described. Other mechanisms include alteration of PBPs and the reduction of penetration rate across the outer membrane. Combination of these two mechanisms with the production of OXA-type β-lactamases or with class C cephalosporinases can lead to resistance to carbapenems. The reduced expression of PBPs or loss of some outer membrane proteins are related to the increased MIC of carbapenems. Efflux pump system does not appear to influence the resistance to β-lactams. The most active agents against Acinetobacter spp. in this group are imipenem, meropenem, ampicillin or cefaperazon with sulbactam and colistin. Combination therapy can be effective in patients with severe infections caused by multidrug resistant strains of Acinetobacter spp.
 
Primary metabolic sources of novobiocin are pictured
Streptomyces vinaceus L-6 Ultrastructural features of a high-viomycin-yielding cell of the mycelium. Abbreviations: cw-cell wall; Arrows showing organelles filled with electron-dense dark contents.
Penicillium chrysogenum PQ-96, high-penicillin-yielding strain Ultrastructural features of a productive cell of the mycelium. Abbreviations: cw -cell wall, sv -secretion vesicles, M -mitochondria, P -peroxisomes, l -lipid body, t -tonoplast, V -vacuole, Dp -degradation products of peroxisomal matrix, square -ribosomes and a polyribosome is visible.
Penicillium chrysogenum PQ-96, high-penicillin-yielding strain Abbreviations: cw -cell wall, V -vacuole, Px -vacuolar pexophagy.
Article
In this article, the secondary metabolism as a basis for antibiotics production by industrial strains of Streptomyces, Penicillium chrysogenum and Acremonium chrysogenum is discussed. Images from transmission electron microscopy reveal some important features of the mycelial cells which are related to antibiotics biosynthesis. This discovery is important for further industrial strain improvement and has economic significance. Possibilities of new strategies for antimicrobial treatment are discussed.
 
The peroxisomal conversion of IPN to Pen N by the two protein cefD1-cefD2 epimeryzation system composed of: IPN-CoA synthetase and IPN-CoA epimerase is shown. Al other steps in cephalosporin C biosynthesis are located in the cytosol (Author: W. Kurzątkowski)
A. chrysogenum (high-yielding, industrial strain). The youngmature sub-apical productive non-growing mycelial cell can be characterized as follow. The protein reach cytoplasm is densely packed with ribosomes and mitochondria (M), that are associated with peroxisomes (p) of about 0.1-0.2 μm in diameter. The cell wall (cw) is composed of one thin electron transparent layer, bar = 1 μm (Author: W. Kurzątkowski).
Article
Cephalosporin C biosynthesis is a compartmentalized process located mainly in the sub-apical, productive, non-growing cells of the hyphae, which under the conditions of the industrial technology build well-dispersed flocculent mycelia. In this paper, the cephalosporin C production by industrial strains of Acremonium chrysogenum (syn. Cephalosporium acremonium) is described, including the central role of peroxisomes in the biosynthesis and secretion of this antibiotic and other beta-lactams. The localization of the pathway of cephalosporin C biosynthesis and important transport steps of intermediates and the end-products are also discussed.
 
Article
Periodontal diseases are a group of chronic inflammatory diseases of the gingiva and the supporting structure of the periodontium that lead to the destruction of the tooth supporting tissues, i.e. the periodontal ligament, the gingival connecting tissue, and the alveolar bones. Actinobacillus actinomycetemcomitans has been implicated, as a causative agent of localized aggressive periodontitis, in severe and rapid form of periodontal disease. The pathogenicity of A. actinomycetemcomitans is multi-faceted and the pathophysiology of the infection is influenced by both microbial and host determinants. The bacterium has been found to be capable of binding to and invading epithelial and endothelial cells. The process is an important mechanism for evading host defenses and spreading beyond the initial site of infection. A. actinomycetemcomitans expresses a number of virulence factors including many adhesins, two toxins (leukotoxin RTX, CDT toxin) and chaperonin 60, which allows the bacterium to form extremely tenacious biofilm and to interact with the immune system. This review describes recent findings concerning the molecular aspects of A. actinomycetemcomitans pathogenesis. 1. Infectious diseases of the oral cavity. 1.1 Periodontitis. 2. Actinobacillus actinomycetemcomitans - pathogen characterization. 2.1 Genome. 3. Virulence factors. 3.1 Adhesins. 3.2 Invasion. 3.3 Toxins. 3.3.1 Leukotoxin. 3.3.2 CDT toxin. 3.4 GroEL protein. 4. Summary.
 
Article
Actinomycetes are prolific producers of many bioactive metabolites, including antibacterial, antifungal, antiviral or anticancer substances. They belong to Gram-positive bacteria and are isolated from different environments. Among actinomycetes, the Streptomyces genus plays a major role in productivity of metabolites with biological activity and is most widespread all over the world. From the beginning of golden era of antibiotics, actinomycetes metabolites were mainly isolated from the soil. As the obtaining the previously discovered metabolites from terrestrial habitats increases, there are attempts to look for new sources, e.g. seas, oceans, etc. Marine isolates are different from soil actinomycetes in their chemical structures, mode of action or biological activity. Marine sponges are especially rich in actinomycete strains. However, actinomycetes are also isolated from fallen leaves, ants' nests, deserts, Antarctica sediments and snow cores, caves or spider materials.
 
Article
Cellulose is the most abundant source of carbon in the world. This plant polisaccharide is decomposed by several microorganisms. One of the best producers of cellulases which has found industrial applications are fungi from the type Trichoderma. Aport from cellulases, other enzymes which occur in the culture filtrates (i.e. xylanases, proteases, chitinases, and β-1,3-glucanases) are also involved in the hydrolysis of plants biomass and play other significant roles. Three different types of enzymes of T. reesei are involved in the degradation of cellulose. At least two cellobiohydrolases (CBH), several endo-1,4-glucanases (EG) and β-glucosidases have been identified and characterized. CBHI is the dominant enzyme of cellulolytic complex forming up to 60% of the secreted protein by T. reesei. The proportion of CBHII amouts to around 20% and endoglucanase, most of which endoglucanase I (EGI) comprise 10%. β-glucosidases account for only 1% of the total secreted proteins. Molecule of CBHI (which is 18 nm long) consist of three domains: cellulose binding domain, hinge domain and catalytic core domain. Genetic improvements of T. reesei QM6a and its deratives for cellulase production has been investigated in several laboratories and hyperproductive mutants were obtained by treatment with UV light, gamma irradiation or diethyl sulphate. The application of genetic engineering to Trichoderma has made it possible to modulate cellulase production in such away that new T. reesei strains producing novel cellulase profiles are now available. Irrespective of genetic engineering advancement, it seems that the knowledge of regulatory machanism of cellulases is required for increased production of these enzymes, β-1,4-xylan, next to cellulose is the most abundant hemicellulose fraction. Due to structural heterogeneity, xylan degrading enzyme system includes several hydrolytic enzymes. One of the best known of these enzymes are endo-β-1,4-xylanases which attact the main chain of xylan and β-xylosidase which hydrolyses xylooligosaccharides to D-xylose. Recently, trend of research seems to develop towards production cellulase-free β-1,4-xylanases. Such preparations are used in kraft pulp for bleaching processes as an alternative to chlorine-based methods.
 
Article
Bacteriocins are a diverse group of ribosomally synthesized peptides or proteins secreted by bacteria, which help them to compete in their local environments for the limited nutritional resources. Bacteriocins kill or inhibit the growth of other bacteria. Generally, these molecules have a narrow spectrum of antibacterial activity, but some of them demonstrate a broad spectrum of action. Bacteriocins from Gram-negative bacteria are divided into two main groups: high molecular mass proteins (30-80 kDa) known as colicins, and low molecular mass peptides (between 1-10 kDa) termed microcins. Colicins are produced by Escherichia coli strains harbouring a colicinogenic plasmid. Such colicinogenic strains are widespread in nature and are especially abundant in the gut of animals. The biosynthesis of colicins is mediated by the SOS regulon, which becomes activated in the response to DNA damage. The colicin synthesis is lethal for the producing cells as a consequence of the concomitant biosynthesis of the colicin lysis protein. Microcins are usually highly stable molecules, which are resistant to proteases, extreme pH values and temperatures. They are produced by enteric bacteria under stress conditions, particularly nutrient depletion. Microcins are encoded by gene clusters carried by plasmids or in certain cases by the chromosome. In this review, we have summarized the most important information about structure and properties of bacteriocins from Gram-negative bacteria, their diverse mechanisms of action and potential application as food preservatives and in livestock industry.
 
Article
Among the currently used biological wastewater treatment systems, the conventional floccular-sludge method has been the most common. Its relatively novel alternative is aerobic granular activated sludge, which offers numerous operational and economic advantages. Although the activated sludge for modern wastewater treatment is often exposed to high concentrations of diverse chemicals, particularly inhibitory and recalcitrant ones, its autochthonous microorganisms may not be familiar with these compounds and can not use them as carbon and energy sources. For this reason, bioaugmentation, defined as a method for improvement of the degradative capacity of contaminated environment by adding selected strains or consortia of microorganisms, seems to be an attractive solution to overcome the problems associated with the exposure of sewage plants to high concentrations of xenobiotics. The most important step in the achievement of successful bioaugmentation is the selection of proper microorganisms with desirable abilities. They should be characterized by high degradative potential towards specific pollutant(s), ability to form biofilm, aggregation and production of extracellular polymeric substances, bioflocculating activity, motility, biosurfactants and autoinductors synthesis. Moreover, they should survive after inoculation into the activated sludge and possess the ability to incorporate into the flocs or form granules. In bioaugmentation of the activated sludge, several approaches can be distinguished - bioaugmentation with: single strains of bacteria or fungi, consortia of bacteria, consortia of fungi or mixed consortia, genetically modified microorganisms and commercial formulations. As many studies have indicated, bioaugmentation is an effective technology for eliminating from sewage toxic compounds, such as phenols and its derivatives, polycyclic aromatic hydrocarbons, dyes, pharmaceuticals and many others.
 
Article
Successful replication of the viral genome and the spreading of progeny virions are ensured by a repertoire of virus-encoded immunomodulatory proteins, which enable avoiding different mechanisms of cell response which are directed against pathogens. These strategies have also been evolved by poxviruses, which are being studied extensively due to the threat of the recurrence of smallpox caused by variola virus (VARV). This work describes three model viruses that are used in smallpox pathogenesis studies: vaccinia virus (VACV), ectromelia virus (ECTV) and cowpox virus (CPXV) and their influence on nuclear factor κB (NF-κB) activation. NF-κB is a widely studied multifunctional transcription factor that regulates both innate and adaptive mechanisms of immune response. The classical pathway of NF-κB activation is stimulated by viral infections; moreover, it can be modified by viral gene products. Poxvirus immunomodulatory proteins that interfere with NF-κB activation can be divided into several groups: ligand inhibitors, intracellular inhibitors of NF-κB, ankyrin repeat (ANK) NF-κB inhibitors and PYRIN domain (PYD) NF-κB inhibitors. The studies on their influence on the host immune response will lead to better understanding of viral pathogenesis and may help in drug and vaccines engineering in the future.
 
Article
Macrophages apoptosis activation is very important element of Salmonella rods virulence. This process lets in infection spreading on whole body, simultaneously bacteria avoid immunological system. In course of Salmonella depended programmed cell death at least two ways could be favored: the early apoptosis, which occurs about 45-60 minutes after bacteria internalization into macrophage and the late programmed cell death, which begins 12-20 hours later. For early apoptosis proteins encoded by genes localized in first Salmonella pathogenicity island are responsible. For late apoptosis proteins encoded by genes localized in second Salmonella pathogenicity island are responsible instead.
 
Article
Gram-negative bacteria are covered by cells membrane, peptydoglycan and outer membrane. Outer membrane contains phospholipids, outer membrane proteins (OMPs) and lipopolysaccharides (LPS). The possibility of activation of innate system by bacterial cell structures depends on the structure and organisation of bacterial outer membrane. Sialic acid not a common component in bacteria has been found in O-specific region of LPS, of some serotypes, as a component of the capsular polysaccharide of envelope and plays an essential role in protecting Gram-negative bacteria against bactericidal activity of serum. Molecular mimicry is called as structural, serological and functional homology and similarity between microbial antigens and host tissue. This homology is considered as important pathogenic factor involved in several autoimmune diseases. Molecular mimicry of host structures by bacterial lipopolysaccharides, capsules and outer membrane proteins has been reporter to contribute to the pathogenesis of certain bacteria.
 
Article
Microbiological diagnosis can help to establish the etiological factor of acute pharyngotonsillitis, otitis media and sinusitis only of appropriate specimens have been collected. Since relevant specimens for the diagnosis of otitis media and sinusitis have to be obtained with the usage of invasive procedures, microbiological diagnosis in both diseases is not routinely recommended. Administration of antibiotic therapy depends on clinical examination and the course of infection. The choice of antibiotic should be based on the recommendations. In Poland, the antibiotic of choice to treat acute bacterial otitis media and sinusitis is amoxicillin. In acute pharyngotonsillitis, microbiological examination is essential to confirm streptococcal etiology. It is not required if clinical examination suggests viral pharyngitis. To confirm or exclude streptococcal pharyngitis, throat swab should be obtained to perform rapid antigen detection test (RADT) or culture. Only patients with microbiologically confirmed streptococcal pharyngitis should be treated with antibiotic. Penicillin is the drug of choice to treat streptococcal pharyngotonsillitis. Inappropriate specimens should not be the subject of microbiological examination. The results of microbiological examination should provide physicians with interpretation, they cannot only contain the list of cultured bacteria. The discrimination should be done between etiological factors, normal flora and carrier state. Such approach can decrease unnecessary antibiotic use in the treatment of acute upper respiratory tract infections. It can also curtail the increasing antibiotic resistance among respiratory pathogens.
 
Article
Saccharomyces sensu stricto yeasts includes important strains for many biotechnological procesess, specially in wine and brewery fermentation. Their plasticity and adaptation to different industrial niches may be result of complex genomic construction, polyploidy, chromosomal rearragements, DNA transfer, SNP occurrence. "Mixed" genetic lines known as hybrids, have more adaptation "abilities" than "pure" lines. Genomic datas from the first strain yeast S288c, sequencing in 1996, and from many others sequencing strains from different origins and applications was obtained. Adaptative evolution of industrial yeast using different molecular tools became as important area to research in last few years.
 
Article
Pathogen recognition and function of innate system, distinct from the adaptive one is stressed. The significance of cytokines, especially interferon (IFN) type I in the development of both innate and adaptive antiviral immunity is reviewed. The role of DC, NK and B1a cells, that join the innate and adaptive immunity is presented. Functional diversity of dendritic cells into DC1 and DC2 cells as well as NK into NK1 and NK2 cells is also presented. The most importance of the cross-talk between NK and DC in the development and regulation both innate and adaptive immunity was stressed.
 
Article
Escherichia coli is a highly diverse and one of the best characterized bacterial genus. The species comprises many commensal strains, colonizing human and animal intestines, as well as pathogenic strains, which can cause gastrointestinal infections. Enteropathogenic E. coli (EPEC) group strains is the pathotype of diarrheagenic E. coli, which is associated with infant diarrhea. The hallmark of EPEC infections is their ability to produce attaching and effacing (A/E) lesions as a result of intimate bacterial adherence to enterocytes and the translocation of bacterial proteins through type III secretion system. The multifunctional and interdependent properties of the effectors contribute to the host cell disruption. The consequences of EPEC infection are: the reorganization of the host cell cytoskeleton underneath adherent bacteria, inhibition of nutrient and water transport, mitochondrial dysfunctions, weak intestinal inflammation, epithelial barrier function disruption and severe watery diarrhea. Despite the recent knowledge development, the mechanism of EPEC diarrhea is still ambiguous. Due to the absence of a proper animal model, further studies should be conducted in volunteers or at least in primates to determine the underlying mechanisms.
 
Article
This review paper presents a basic knowledge about factors affecting the adhesion of microorganisms to solid surfaces. Bacterial colonisation of abiotic surfaces has important consequences in medicine (contamination of prostheses and catheters) and in the food industry (contamination of food product lines). Adhesion process includes the following steps: physical interactions between microorganisms and surface (transport of microorganisms to the substrate), initial nonspecific adhesion of bacteria to unprotected sites of the substrate, specific adhesion (mainly microbial interactions) and biofilm formation. The adhesion of microorganisms to the surface is one of the first stages in the development of a biofilm and is influenced by a number of factors, such as: hydrophobicity of cell surface, extracellular production of polymeric substances (mainly proteins and polysaccharides), factors connected with physico-chemical properties of solid surface, environmental factors (kind of media, ionic strength, pH, presents of surfactants and polyvalent ions) and other factors (growth phase of microorganisms, viability of cells, microbial competition). A lot of disagreements were appeared in the literature relating which factors and haw far affecting the adhesion of microorganisms to solid surfaces. The apparent conflict in these observations is probably related to the bacterial species tested, the method used to detect bacteria on the surface, the physico-chemical parameters of the surface and the degree of surface roughness. Studies on attachment of microorganisms to solid surface represents important aspects in the establishment decontamination procedures directed of minimalizing health hazards.
 
Article
The urinary tract is a common site of bacterial infection, and Escherichia coli is by far the most common infecting agent at this site (80%). Surface virulence factors of pathogenic bacteria include various adhesive polymeric structures (pili/fimbriae) responsible for the recognition of specific cellular receptors. The interaction between adhesin and the selected receptor is a crucial step in pathogenesis. The most common adhesive structures of E. coli are type 1 pili and type P pili causing cystitis and pyelonephritis, respectively. The third group of E. coli adhesive factors (30-50% of cases of cystitis and 30% of cases of pyelonephritis in pregnant women and diarrhoea in infants) are adhesins belonging to the Dr family. The members of this family of adhesins are able to bind to human-decay accelerating factor (DAF) on the surface of urinary epithelial cells and promote DAF mobilization. The physiologic agent which enables a colonization of urinary tract by E. coli in pregnant women is the pregnancy. Pyelonephritis in pregnant women is a serious complication leading to bacteremia, urosepsis, acute respiratory distress syndrome and even death. The course of the pregnancy may be affected and may result in preterm labor and intrauterine growth retardation. The biogenesis of the adhesive polymeric structures is highly conserved among Gram-negative bacteria. Recently, compounds that inhibit pilus biogenesis and interfere with chaperone-subunit interactions have been discovered and termed pilicides. The pilicides target key virulence factors in pathogenic bacteria and thus are a promising cobdidate for developing drugs that would function by targeting virulence factors.
 
Article
The ability of Lactobacillus to adhere to the intestinal epithelium is one of the most important criterion in the selection of probiotic strains. Adherence allows microorganisms to survive and temporarily colonize the digestive system, which is necessary to induce beneficial effects on the host. Adhesion is a very complex, multistep process and, although there are many proposed theories, the exact mechanism is still not fully understood. A crucial role in the formation of the adhesive interactions plays the bacterial cell wall and its components, such as exopolisaccharydes, lipoteichoic acids and various proteins e.g. S-layer proteins.
 
Top-cited authors
Sebastian Gnat
  • University of Life Sciences in Lublin
Aneta Nowakiewicz
  • University of Life Sciences in Lublin
Monika Staniszewska
  • Warsaw University of Technology
Elzbieta Katarzyna Jagusztyn-Krynicka