In light of an increasing number of antibiotic-resistant bacterial strains, it is essential to understand an action imposed by various antimicrobial agents on bacteria at the molecular level. One of the leading mechanisms of killing bacteria is related to the alteration of their plasmatic membrane. We study bio-inspired peptides originating from natural antimicrobial proteins colicins, which can disrupt membranes of bacterial cells. Namely, we focus on the α-helix H1 of colicin U, produced by bacterium Shigella boydii, and compare it with analogous peptides derived from two different colicins. To address the behavior of the peptides in biological membranes, we employ a combination of molecular simulations and experiments. We use molecular dynamics simulations to show that all three peptides are stable in model zwitterionic and negatively charged phospholipid membranes. At the molecular level, their embedment leads to the formation of membrane defects, membrane permeation for water, and, for negatively charged lipids, membrane poration. These effects are caused by the presence of polar moieties in the considered peptides. Importantly, simulations demonstrate that even monomeric H1 peptides can form toroidal pores. At the macroscopic level, we employ experimental co-sedimentation and fluorescence leakage assays. We show that the H1 peptide of colicin U incorporates into phospholipid vesicles and disrupts their membranes, causing leakage, in agreement with the molecular simulations. These insights obtained for model systems seem important for understanding the mechanisms of antimicrobial action of natural bacteriocins and for future exploration of small bio-inspired peptides able to disrupt bacterial membranes.

• Klíčová slova
• Colicins, Leakage, Lipid membranes, Molecular dynamics, Permeation, Poration,
• MeSH
• fosfatidylcholiny chemie   MeSH
• fosfatidylethanolaminy chemie   MeSH
• fosfolipidy chemie   MeSH
• koliciny chemie   metabolismus   farmakologie   MeSH
• konformace proteinů, alfa-helix MeSH
• permeabilita účinky léků   MeSH
• sekvence aminokyselin MeSH
• Shigella boydii metabolismus   MeSH
• simulace molekulární dynamiky MeSH
• unilamelární lipozómy chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-palmitoyl-2-oleoylphosphatidylcholine MeSH Prohlížeč
• 1-palmitoyl-2-oleoylphosphatidylethanolamine MeSH Prohlížeč
• fosfatidylcholiny MeSH
• fosfatidylethanolaminy MeSH
• fosfolipidy MeSH
• koliciny MeSH
• unilamelární lipozómy MeSH

We report a highly sensitive and selective multiplex assay by empowering an electrochemical DNA sensor with isothermal rolling circle amplification. The assay could simultaneously detect and discriminate three common entero-pathogens in a single reaction, with femtomolar sensitivity. It is useful for field- or resource-limited settings.

• MeSH
• biosenzitivní techniky * MeSH
• DNA genetika   MeSH
• elektrochemické techniky * MeSH
• Salmonella typhi izolace a purifikace   MeSH
• Shigella flexneri izolace a purifikace   MeSH
• techniky amplifikace nukleových kyselin * MeSH
• Vibrio cholerae izolace a purifikace   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA MeSH

Globally, it is estimated that there are 2 billion cases of diarrhoeal disease each year, with 525,000 children under the age of 5 years, dying from diarrhoea. This also affects 1 in 5 people in the UK each year. Rapid diagnosis, appropriate treatment and infection control measures are, therefore, particularly important. Currently, Public Health Wales and England Microbiology Division test for five key bacterial gastrointestinal pathogens, i.e. Escherichia coli O157 (VTEC), Shigella dysenteriae, Salmonella spp., Campylobacter spp. and Clostridioides difficile. There is, however, a poor success rate with identification of these pathogens, leaving the patient at risk from untreated infections. This study has developed effective and reliable tools with a high positive outcome for diagnosis of diarrhoeal infection. The study blindly analysed 592 samples, with the most abundant species being Shigella sonnei at 15%, and the top genus Bacteroides at 26%. Campylobacter spp. had an abundance of 4%, Clostridium difficile 3%, and Salmonella spp. 0.2%. There were also significant differences in abundance at genus level, between the Flemish Gut project and diarrhoea samples, with respect to Shigella (0.2%) and Campylobacter (0.1%). The project introduced a novel Shigella spp. (Escherichia) threshold of 5.32% to determine (Escherichia) a healthy or unhealthy community. A DMBiome model was developed to integrate the 5.32% threshold of Shigella spp., the Public Health laboratory tested pathogens, and two emerging enteropathogens. The overall positive outcome was that 89% of all samples were diagnosed with diarrhoea infections, leaving 11% unknown.

• Klíčová slova
• 16S rRNA genes, Diagnostics, Diarrhoea, Microbiome, Shigella spp,
• MeSH
• Bacteria * genetika   izolace a purifikace   MeSH
• Campylobacter genetika   MeSH
• feces mikrobiologie   MeSH
• lidé MeSH
• mikrobiologické techniky * metody   normy   MeSH
• průjem * diagnóza   mikrobiologie   MeSH
• Shigella * genetika   izolace a purifikace   MeSH
• vysoce účinné nukleotidové sekvenování * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Although multiprotein membrane complexes play crucial roles in bacterial physiology and virulence, the mechanisms governing their quality control remain incompletely understood. In particular, it is not known how unincorporated, orphan components of protein complexes are recognised and eliminated from membranes. Rhomboids, the most widespread and largest superfamily of intramembrane proteases, are known to play key roles in eukaryotes. In contrast, the function of prokaryotic rhomboids has remained enigmatic. Here, we show that the Shigella sonnei rhomboid proteases GlpG and the newly identified Rhom7 are involved in membrane protein quality control by specifically targeting components of respiratory complexes, with the metastable transmembrane domains (TMDs) of rhomboid substrates protected when they are incorporated into a functional complex. Initial cleavage by GlpG or Rhom7 allows subsequent degradation of the orphan substrate. Given the occurrence of this strategy in an evolutionary ancient organism and the presence of rhomboids in all domains of life, it is likely that this form of quality control also mediates critical events in eukaryotes and protects cells from the damaging effects of orphan proteins.

• Klíčová slova
• Shigella, intramembrane proteolysis, membrane protein complexes, quality control, rhomboid,
• MeSH
• bakteriální proteiny chemie   metabolismus   MeSH
• endopeptidasy chemie   metabolismus   MeSH
• membránové proteiny metabolismus   MeSH
• proteinové domény MeSH
• proteolýza MeSH
• Shigella sonnei enzymologie   metabolismus   MeSH
• substrátová specifita MeSH
• transport elektronů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• endopeptidasy MeSH
• membránové proteiny MeSH

Shigella flexneri is a leading etiologic agent of diarrhea in low socioeconomic countries. Notably, various serotypes in S. flexneri are reported from different regions of the world. The precise approximations of illness and death owing to shigellosis are missing in low socioeconomic countries, although it is widespread in different regions. The inadequate statistics available reveal S. flexneri to be a significant food and waterborne pathogen. All over the world, different antibiotic-resistant strains of S. flexneri serotypes have been emerged especially multidrug-resistant strains. Recently, increased resistance was observed in cephalosporins (3rd generation), azithromycin, and fluoroquinolones. There is a need for a continuous surveillance study on antibiotic resistance that will be helpful in the update of the antibiogram. The shigellosis burden can be reduced by adopting preventive measures like delivery of safe drinking water, suitable sanitation, and development of an effective and inexpensive multivalent vaccine. This review attempts to provide the recent findings of S. flexneri related to epidemiology and the emergence of multidrug resistance.

• MeSH
• antibakteriální látky farmakologie   MeSH
• bacilární dyzentérie farmakoterapie   mikrobiologie   MeSH
• bakteriální léková rezistence MeSH
• lidé MeSH
• objevující se infekční nemoci farmakoterapie   mikrobiologie   MeSH
• Shigella flexneri účinky léků   genetika   izolace a purifikace   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antibakteriální látky MeSH

Colicin U is a protein produced by the bacterium Shigella boydii (serovars 1 and 8). It exerts antibacterial activity against strains of the enterobacterial genera Shigella and Escherichia Here, we report that colicin U forms voltage-dependent pores in planar lipid membranes; its single-pore conductance was found to be about 22 pS in 1 M KCl at pH 6 under 80 mV in asolectin bilayers. In agreement with the high degree of homology between their C-terminal domains, colicin U shares some pore characteristics with the related colicins A and B. Colicin U pores are strongly pH dependent, and as we deduced from the activity of colicin U in planar membranes at different protein concentrations, they have a monomeric pore structure. However, in contrast to related colicins, we observed a very low cationic selectivity of colicin U pores (1.5/1 of K+/Cl- at pH 6) along with their atypical voltage gating. Finally, using nonelectrolytes, we determined the inner diameter of the pores to be in the range of 0.7 to 1 nm, which is similar to colicin Ia, but with a considerably different inner profile.IMPORTANCE Currently, a dramatic increase in antibiotic resistance is driving researchers to find new antimicrobial agents. The large group of toxins called bacteriocins appears to be very promising from this point of view, especially because their narrow killing spectrum allows specific targeting against selected bacterial strains. Colicins are a subgroup of bacteriocins that act on Gram-negative bacteria. To date, some colicins are commercially used for the treatment of animals (1) and tested as a component of engineered species-specific antimicrobial peptides, which are studied for the potential treatment of humans (2). Here, we present a thorough single-molecule study of colicin U which leads to a better understanding of its mode of action. It extends the range of characterized colicins available for possible future medical applications.

• Klíčová slova
• Shigella boydii, black lipid membrane, colicin U, ion-selectivity, membrane pores,
• MeSH
• buněčná membrána metabolismus   MeSH
• chlorid draselný farmakologie   MeSH
• gating iontového kanálu MeSH
• koliciny metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• lipidové dvojvrstvy metabolismus   MeSH
• permeabilita MeSH
• Shigella boydii metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chlorid draselný MeSH
• koliciny MeSH
• lipidové dvojvrstvy MeSH

Colicin production in Escherichia coli (E. coli) strains represents an important trait with regard to microbial survival and competition in the complex intestinal environment. A novel colicin type, colicin Z (26.3 kDa), was described as a product of an original producer, extraintestinal E. coli B1356 strain, isolated from the anorectal abscess of a 17 years-old man. The 4,007 bp plasmid (pColZ) was completely sequenced and colicin Z activity (cza) and colicin Z immunity (czi) genes were identified. The cza and czi genes are transcribed in opposite directions and encode for 237 and 151 amino acid-long proteins, respectively. Colicin Z shows a narrow inhibitory spectrum, being active only against enteroinvasive E. coli (EIEC) and Shigella strains via CjrC receptor recognition and CjrB- and ExbB-, ExbD-mediated colicin translocation. All tested EIEC and Shigella strains isolated between the years 1958-2010 were sensitive to colicin Z. The lethal effect of colicin Z was found to be directed against cell wall peptidoglycan (PG) resulting in PG degradation, as revealed by experiments with Remazol Brilliant Blue-stained purified peptidoglycans and with MALDI-TOF MS analyses of treated PG. Colicin Z represents a new class of colicins that is structurally and functionally distinct from previously studied colicin types.

• MeSH
• Escherichia coli genetika   MeSH
• koliciny genetika   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• mladiství MeSH
• plazmidy genetika   MeSH
• sekvence nukleotidů MeSH
• Shigella genetika   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• koliciny MeSH

The aim of this work is to study the epidemiology and antimicrobial resistance to the most commonly used antibiotics for the treatment of acute gastroenteritis caused by Salmonella and Shigella at the largest Bulgarian hospital-University Hospital "St. George," Plovdiv-for the period 2009-2013. Two hundred ninety strains were in vitro tested for resistance to 15 antimicrobial agents. The presence of extended-spectrum beta-lactamases (ESBLs) was demonstrated by a variety of specialized tests. For comparison, a collection of 28 strains submitted by the National Reference Laboratory (NRL) "Enteric Infections" at the National Center of Infectious and Parasitic Diseases (NCIPD), Sofia, was also tested for the production of ESBLs. In isolates, phenotypically demonstrated as ESBL producers, polymerase chain reaction (PCR) detection of the genes bla-CTX-M, bla-SHV, and bla-TEM was performed. Among the 290 tested isolates, only two- Salmonella serotype Livingstone and Shigella flexneri-were phenotypically proven to be ESBL producers. Only 4 strains from the collection of 28, submitted from the NRL "Intestinal Infections" in NCIPD, Sofia, were phenotypically confirmed as ESBL producers. The presence of the bla-CTX-M gene was detected in all of the tested strains (4 from NRL, NCIPD, Sofia, and 2 from the University Hospital St. George, Plovdiv), the bla-SHV gene only in strain S. Livingstone from Plovdiv, and the bla-TEM gene in two from Sofia and one (again S. Livingstone) from Plovdiv. In conclusion, Salmonella and Shigella isolates from patients hospitalized at the University Hospital St. George, Plovdiv, with acute gastroenteritis demonstrate good susceptibility to the most commonly used antibiotic agents, including azithromycin.

• Klíčová slova
• Antimicrobial resistance, ESBL, PCR, Salmonella, Shigella,
• MeSH
• akutní nemoc MeSH
• antibakteriální látky farmakologie   MeSH
• bacilární dyzentérie diagnóza   farmakoterapie   epidemiologie   mikrobiologie   MeSH
• bakteriální léková rezistence genetika   MeSH
• beta-laktamasy genetika   metabolismus   MeSH
• dítě MeSH
• DNA bakterií genetika   MeSH
• dospělí MeSH
• exprese genu MeSH
• gastroenteritida diagnóza   farmakoterapie   epidemiologie   mikrobiologie   MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• mladiství MeSH
• nemocnice univerzitní MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• retrospektivní studie MeSH
• Salmonella účinky léků   enzymologie   genetika   růst a vývoj   MeSH
• salmonelóza diagnóza   farmakoterapie   epidemiologie   mikrobiologie   MeSH
• Shigella účinky léků   enzymologie   genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Bulharsko epidemiologie   MeSH
• Názvy látek
• antibakteriální látky MeSH
• beta-laktamasy MeSH
• DNA bakterií MeSH

Together with plague, smallpox and typhus, epidemics of dysentery have been a major scourge of human populations for centuries(1). A previous genomic study concluded that Shigella dysenteriae type 1 (Sd1), the epidemic dysentery bacillus, emerged and spread worldwide after the First World War, with no clear pattern of transmission(2). This is not consistent with the massive cyclic dysentery epidemics reported in Europe during the eighteenth and nineteenth centuries(1,3,4) and the first isolation of Sd1 in Japan in 1897(5). Here, we report a whole-genome analysis of 331 Sd1 isolates from around the world, collected between 1915 and 2011, providing us with unprecedented insight into the historical spread of this pathogen. We show here that Sd1 has existed since at least the eighteenth century and that it swept the globe at the end of the nineteenth century, diversifying into distinct lineages associated with the First World War, Second World War and various conflicts or natural disasters across Africa, Asia and Central America. We also provide a unique historical perspective on the evolution of antibiotic resistance over a 100-year period, beginning decades before the antibiotic era, and identify a prevalent multiple antibiotic-resistant lineage in South Asia that was transmitted in several waves to Africa, where it caused severe outbreaks of disease.

• MeSH
• bacilární dyzentérie epidemiologie   dějiny   mikrobiologie   MeSH
• bakteriální léková rezistence MeSH
• celosvětové zdraví MeSH
• dějiny 19. století MeSH
• dějiny 20. století MeSH
• dějiny 21. století MeSH
• fylogeografie * MeSH
• genom bakteriální MeSH
• lidé MeSH
• molekulární epidemiologie MeSH
• molekulární evoluce * MeSH
• sekvenční analýza DNA MeSH
• séroskupina * MeSH
• Shigella dysenteriae klasifikace   genetika   izolace a purifikace   MeSH
• Check Tag
• dějiny 19. století MeSH
• dějiny 20. století MeSH
• dějiny 21. století MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• historické články MeSH

• MeSH
• antibakteriální látky farmakologie   MeSH
• bacilární dyzentérie mikrobiologie   MeSH
• beta-laktamasy biosyntéza   MeSH
• beta-laktamová rezistence * MeSH
• cestování * MeSH
• dospělí MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• Shigella sonnei klasifikace   účinky léků   enzymologie   izolace a purifikace   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• dopisy MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Asie MeSH
• Česká republika MeSH
• Názvy látek
• antibakteriální látky MeSH
• beta-lactamase CTX-M-15 MeSH Prohlížeč
• beta-laktamasy MeSH