Microbial diversity of internal environment of Johann Gregor Mendel Station, Antarctica

During January and February 2011 two sets of microbiological samples were collected inside the main building of Johann Gregor Mendel station located at the James Ross Island near the coast of Antarctica. The aim was to examine the changes of microbial profile of the antarctic station environment. The first set of samples was collected from the station environment before the staff entry, i.e. after 10 months of quiescent state when nobody was present at the station. The second set of samples was collected from the same places before the Antarctic expedition staff left the station after 45 days of the stay. The cultivation of samples was focused on mesophilic bacteria. Twenty-three strains were obtained from the Set No. 1 and 27 strains were obtained from the Set No. 2. However, 8 strains from each set were not reliably identified by mass spectrometry. Altogether 13 strains of Gram-positive bacteria were identified in the Set. No. 1, while only 7 in the Set No. 2. Contrastingly, Gram-negative bacteria were much more abundant in the Set No. 2 (12 strains) than in the Set No. 1 (2 strains). Bacillus sp. was the most common Gram-positive strain (9 isolations from the first set, 2 isolations from the second set). Pantoea agglomerans was the most common Gram-negative strain (2 isolations from the first set, 7 isolations from the second set). The first experience with the microbial profile of the research station showed that we were able to detect mainly bacteria commonly present in the outer environment that could survive under extreme conditions. We did not isolate any microbes related to human colonisation except of enterococci and Escherichia vulneris. For further investigation of the station environment, it will be necessary to choose alternative way of collection and storage of samples to ensure survival of all present bacteria

Human extraintestinal pathogenic Escherichia coli strains differ in prevalence of virulence factors, phylogroups, and bacteriocin determinants

Table S4. Differences in the distribution of virulence factors, E. coli phylogroups, bacteriocin production, and bacteriocin determinants between subgroups of ExPEC strains and fecal strains. (XLSX 14 kb

Možnosti řešení rozpadavosti CT-směsi s vodním sklem (teoretická práce)

PrezenčníNeuvedenoNeuveden

Bacteriocin synthesis in uropathogenic and commensal <it>Escherichia coli</it>: colicin E1 is a potential virulence factor

Abstract Background Bacteriocin production is an important characteristic of E. coli strains of human origin. To date, 26 colicin and 9 microcin types have been analyzed on a molecular level allowing molecular detection of the corresponding genes. The production incidence of 29 bacteriocin types and E. coli phylogroups were tested in a set of 361 E. coli strains isolated from human urinary tract infections (UTI) and in 411 control strains isolated from feces of patients without bacterial gut infection. Results Production of 17 and 20 individual bacteriocin types was found in the UTI and control strains, respectively. Microcin H47 encoding determinants were found more often among UTI strains compared to controls (37.9% and 27.0% respectively, p = 0.02) and strains producing microcin H47 belonged predominantly to phylogroup B2 when compared to other bacteriocin producers (67.4% and 36.7%, respectively; p vice versa suggesting that pColE1 was independently associated with pColIa in UTI strains. Conclusion E. coli strains isolated from human urinary tract infections showed increased incidence of microcin H47 and colicin E1 production, respectively. Moreover, colicin E1 itself appears to be a potentially important virulence factor of certain uropathogenic E. coli strains.</p

Unique Activity Spectrum of Colicin F_Y: All 110 Characterized <i>Yersinia enterocolitica</i> Isolates Were Colicin F_Y Susceptible

<div><p>Colicin F_Y is a plasmid encoded toxin that recognizes a yersinia-specific outer membrane protein (YiuR) as a receptor molecule. We have previously shown that the activity spectrum of colicin F_Y comprises strains of the genus <i>Yersinia</i>. In this study, we analyzed the activity of colicin F_Y against 110 <i>Yersinia enterocolitica</i> isolates differing in geographical origin and source. All isolates were characterized through analysis of 16S rRNA genes, serotyping, biotyping, restriction profiling of genomic DNA, detection of virulence markers and susceptibility to antibiotics. This confirmed the broad variability of the collection, in which all 110 <i>Y. enterocolitica</i> isolates, representing 77 various strains, were inhibited by colicin F_Y. Although isolates showed variable levels of susceptibility to colicin F_Y, it was not associated with any strain characteristic. The universal susceptibility of <i>Y. enterocolitica</i> strains to colicin F_Y together with the absence of activity towards strains outside the <i>Yersinia</i> genus suggests potential therapeutic applications for colicin F_Y.</p></div

Sequence variability between highly and less susceptible <i>Y. enterocolitica</i> isolates.

<p>A) Sequence analysis of YiuR protein from various isolates identified variability in 26 amino acid posistions. B) Sequence analysis of TonB from various isolates identified variability in 18 amino acid positions. A consensus sequence is shown at the top of the figure. The numbers correspond to amino acid position in the YiuR and TonB proteins, respectively.</p

Identified pulsotypes among <i>Y. enterocolitica</i> isolates.

<p>Similarities (%) between restriction patterns were calculated using the Dice's index and are shown as the numbers close to nodes. The data were sorted using the UPGMA method. For construction of this dendrogram, 41 <i>Y. enterocolitica</i> pulsotypes with similarity lower than 85% were selected from a dendrogram containing all 110 isolates (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081829#pone.0081829.s001" target="_blank">Fig. S1</a>). Susceptibility to colicin F_Y is shown in the right panel, followed by additional strain characteristics. Colicin F_Y titers are shown as the reciprocal exponent of the highest four-fold dilution causing clear (light grey) and turbid (dark grey) zones of inhibition. Subspecies: P =  <i>palearctica</i>, E =  <i>enterocolitica</i>. *Serotypes O:1 and O:2 have been combined to O:3 serotype according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081829#pone.0081829-Aleksi1" target="_blank">[1]</a>.</p