Browsing tag: bakteriofagi

Czynniki wirulencji Staphylococcus aureus zależne od bakteriofagów

Phage-related virulence factors of Staphylococcus aureus
W. M. Helbin, K. Polakowska, J. Międzobrodzki

1. Wprowadzenie. 2. Wpływ bakteriofagów na wirulencję gatunku Staphylococcus aureus. 3. Gronkowcowe wyspy patogenności SaPIs (staphylococcal pathogenicity islands). 4. Wpływ antybiotyków na odpowiedź SOS i indukcję bakteriofagów. 5. Podsumowanie

Abstract: Mobile genetic elements play fundamental role in the emergence of new pathogens and in the adaptation of all bacteria species to the enviromnent. It is believed that the horizontal gene transfer has a major impact on genome structure of Staphylococcus aureus which of both commensal and major pathogen of humans and warm-blooded animals. Bacteriophages via lysogenic conversion are source of the major staphylococcal virulence factors, contribute to strain diversity and enable rapid changes in host specificity. Bacteriophages have also close connection to other kind of mobile genetic elements, known as staphylococcal pathogenicity islands, SaPIs. SaPIs excision from chromosome and replication is possible only after infection of a particular phage and the islands are able to leave the host cell inside hijacked capsids. Horizontal transfer of SaPIs which occurs through a modified transduction may be responsible for spread of toxic-shock syndrome toxin TSST-1, and other superantigenes among S. aureus
strains, and possibly from S. aureus to other species. Recently it has been reported that β-lactam and fluorochinolone antibiotic in subinhibitory concentration promote SOS-mediated prophage induction, replication of SaPIs in its host cells and consequently the further spread of SaPIs, and lysogenic conversion genes in pathogenic bacteria. Further understanding of phage and phage-dependent mobile genetic elements can provide insight into staphylococcal virulence and help in the development of efficient treatment of S. aureus infections.
1. Introduction. 2. Effect of bacteriophages on the virulence of Staphylococcus aureus. 3. Staphylococcal pathogenicity islands SaPIs. 4. Antibiotic dependent SOS response and the induction of prophages. 5. Summary

Typowanie bakteriofagowe w diagnostyce pałeczek Salmonella Enteritidis występujących w Polsce

Phage typing in the diagnostic of Salmonella Enteritidis occurring in Poland
B. Dera-Tomaszewska, E. Tokarska-Pietrzak

1. Wprowadzenie. 2. Typowanie bakteriofagowe. 3. Schematy typowania bakteriofagowego pałeczek Salmonella. 4. Typy bakteriofagowe Salmonella Enteritidis występujące w Polsce. 5. Podsumowanie

Abstract: Phage typing has a long history with regard to the differentiation of Salmonella serovars of human and animal origin. This method provides the fast and cheap characterization of frequent serovars on the sub-serovar level and is especially useful for primary epidemiological analysis before investigation by other, more expensive molecular techniques. Since the discovery of bacteriophages many different Salmonella typing schemes have been developed. More than one typing scheme may have been developed for a serovar. Several phage-typing schemes have been published for Salmonella Enteritidis. The most widely used is that of Ward et al. In Poland a different typing scheme is used − the Lalko et al. scheme. It employs eight typing phages for differentiation more than 20 phage types. Basing on the results of Salmonella Enteritidis phage typing, which has been conducted in Poland for many years, it can be noted that Salmonella Enteritidis infections reported in our country during the last fifty years were associated with two serious epidemics. Among the strains isolated during the first epidemic, phage types 2, 5, 7, 8 and 12 were predominant and the great majority of the strains were represented by types 8 and 5. Phage types 1, 6 and 7 were found to be dominated during 27 years of the second Salmonella Enteritidis epidemic in Poland. The strains of type 7 were the most numerous ones. The results of phage typing indicate that sources of infections of these two Salmonella Enteritidis epidemics are quite different. However, a relationship between them exists: Salmonella Enteritidis type 7 organisms occur in both. During the first epidemic they were isolated in a relatively small percentage and only from humans. The great majority of sources of Salmonella Enteritidis infections associated with the second epidemic were dominated by them. They were also prevalent in human isolates. Generally, during the last 27 years, no significant changes in the distribution of Salmonella Enteritidis phage types in Poland have been observed. Although, it is noteworthy that except the same, permanent phage types continuously existing in the environment, the new types start to appear. They can suggest an appearance of new sources of Salmonella Enteritidis infections, unknown yet in our country, which is very possible as a result of effective elimination of currently existing ones.

1. Introduction. 2. Phage typing. 3. Salmonella phage typing schemes. 4. Salmonella Enteritidis phage types occurring in Poland. 5. Summary

Bakteriofagi i drapieżniki bakterii jako czynniki limitujące liczbę bakterii w środowisku

Bacteriophages and bacterial predators as agents limiting the amount of bacteria in the environment
A. Wierzbicka-Woś, W. Deptuła

1. Wprowadzenie. 2. Bakteriofagi a bakterie w środowisku. 3. Bakterie drapieżne z grupy BALO a bakterie w środowisku. 4. Pierwotniaki a bakterie w środowisku. 5. Drapieżniki bakterii a biofilm. 6. Mechanizmy obronne bakterii oraz ich interakcje z drapieżnikami. 7. Praktyczne wykorzystanie drapieżników bakterii. 8. Podsumowanie

Abstract: Bacterial predators, such as Bdellovibrio and Bdellovibrio like organisms (BALOs), protozoa and bacteriophages, are the major cause of bacterial mortality. Howeverthe correlations between these microorganisms enable their coexistance in the same ecological niche. This review presents the interactions between bacterial prey and their predators, and bacteriophages. In addition, it describes bacterial adaptations helping bacteria to prevent the attack. Taking into account current problems with increasing antibiotic resistance of pathogenic microorganisms, this observations can lead us to the discovery of novel antimicrobial compounds, which are common in nature, and could be used in the future against animal and human pathogens. Moreover, these microorganisms might be also a potentialsource of novel biocatalysts, which could be applied in biotechnological processes.

1. Introduction. 2. Bacteriophages and bacteria in the environment. 3. Bacterial predators from BALO and bacteria in the environment. 4. Protozoa and bacteria in the environment. 5. Bacterial predators and biofilm. 6. Defense mechanisms of bacteria and their interactions with predators. 7. Practical use of bacterial predators. 8. Summary