[show abstract][hide abstract] ABSTRACT: Multidrug-resistant Pseudomonas aeruginosa is a serious challenge for antimicrobial therapy of nosocomial infections, as it possesses several mechanisms of antimicrobial resistance. In Central Greece, a sudden increase of infections caused by carbapenem-resistant P. aeruginosa was observed during 2011, indicating the need for further analysis.
Five-hundred and sixty-eight P. aeruginosa isolates were collected consecutively during an 8-month period in 2011 from inpatients treated in three hospitals in the Thessaly region (1,000,000 habitants) of Greece. Carbapenem-resistant P. aeruginosa (n = 284) were characterized by antimicrobial susceptibility testing and beta-lactamase content, and the genetic relatedness of carbapenemase-producing isolates was assessed by BOX-PCR, multilocus sequence typing, and eBURST analysis. Mapping of the class I integrons of Verona integron-encoded metallo-beta-lactamase (VIM)-carrying isolates was also performed, and clinical data of the VIM producers were reviewed.
Eighty (14.1%) out of the 568 P. aeruginosa isolates recovered from clinical specimens were VIM producers. Multilocus sequence typing revealed high prevalence of the international clones ST111 and ST235 among blaVIM-2- and blaVIM-4-positive isolates, respectively. blaVIM-17 was identified in an isolate of a novel sequence type (ST1457). blaVIM gene cassettes were carried by five distinct class I integrons, including two novel ones.
Since the first report of VIM-producing P. aeruginosa in 2000, this microorganism still remains among the most prevalent multidrug resistant pathogens in Greece. The spread of VIM-producers belonging to the most common international clones (ST111 and ST235), the spread of integrons of divergent structures, and the emergence of novel integrons underscore their ongoing evolution.
[show abstract][hide abstract] ABSTRACT: Cyanobacteria cause aesthetic damage to marble surfaces and in particular their endolithic mode of life contributes to the breakdown of rock crystalline structures. The aim of this work was to estimate, with both phenotypical and molecular approach, the composition of cyanobacterial communities on the Propylaea marbles of the Acropolis Monuments. The two selected sampling sites were treated and untreated with a commercial biocide in order to estimate its effect on the cyanobacterial diversity. Our study revealed that in both sampling sites were present 13 phenotypes and 10 phylotypes and that the cyanobacterial taxa were considerably lower in the treated site.
[show abstract][hide abstract] ABSTRACT: Aim. Tracking the dispersal patterns and habitat use of migratory species is necessary to delineate optimal areas for protection, with large sample sizes being more representative of the population. Here, we examine the dispersal patterns of a key Mediterranean loggerhead turtle (Caretta caretta) breeding population to identify priority foraging sites for protection.
Location. Zakynthos Island, Greece and the wider Mediterranean.
Method. We examined the dispersal patterns and foraging sites of 75 adult loggerheads (n = 38 males and 37 females) tracked from the breeding area of Zakynthos Island (Greece) from 2004 to 2011. We then combined our data with published sea turtle literature to identify key foraging sites for protection.
Results. While both males and females exhibited similar dispersal patterns, about 25% males remained < 100 km of Zakynthos, whereas all females (except one) migrated > 200 km. Integration of our data with the wider literature isolated 10 core sites in proximity to existing protected areas, which could potentially protect 64% of the Zakynthos population, while five sites support individuals from at least 10 other loggerhead breeding populations.
Main conclusions. Due to the widespread availability of neritic foraging grounds across the Mediterranean, sea turtles from Zakynthos exhibit disparate dispersal patterns. However, protecting only a few objectively defined important sites can encompass a large proportion of the foraging areas used and hence
have considerable conservation benefit.
Diversity and Distributions 01/2013; · 6.12 Impact Factor
[show abstract][hide abstract] ABSTRACT: Many studies have shown that several Greek ecosystems inhabit very interesting bacteria with biotechnological properties. Therefore Streptomyces isolates from diverse Greek habitats were selected for their antifungal activity against the common phytopathogenic fungus Fusarium oxysporum. The isolate encoded ACTA1551, member of Streptomyces genus, could strongly suppress the fungal growth when examined in antagonistic bioassays in vitro. The isolate was found phylogenetically relative to Streptomyces rochei after analyzing its 16S rDNA sequence. The influence of different environmental conditions, such as medium composition, temperature, and pH on the expression of the antifungal activity was thoroughly examined. Streptomyces rochei ACTA1551 was able to protect tomato seeds from F. oxysporum infection in vivo while it was shown to promote the growth of tomato plants when the pathogen was absent. In an initial effort towards the elucidation of the biochemical and physiological nature of ACTA1551 antifungal activity, extracts from solid streptomycete cultures under antagonistic or/and not antagonistic conditions were concentrated and fractionated. The metabolites involved in the antagonistic action of the isolate showed to be more than one and produced independently of the presence of the pathogen. The above observations could support the application of Streptomyces rochei ACTA1551 as biocontrol agent against F. oxysporum.
BioMed research international. 01/2013; 2013:387230.
[show abstract][hide abstract] ABSTRACT: In a bioprospecting effort towards novel thermostable lipases, we assessed the lipolytic profile of 101 bacterial strains isolated from the volcanic area of Santorini, Aegean Sea, Greece. Screening of lipase activity was performed both in agar plates and liquid cultures using olive oil as carbon source. Significant differences were observed between the two screening methods with no clear correlation between them. While the percentage of lipase producing strains identified in agar plates was only 17%, lipolytic activity in liquid culture supernatants was detected for 74% of them. Nine strains exhibiting elevated extracellular lipase activities were selected for lipase production and biochemical characterization. The majority of lipase producers revealed high phylogenetic similarity with Geobacillus species and related genera, whilst one of them was identified as Aneurinibacillus sp. Lipase biosynthesis strongly depended on the carbon source that supplemented the culture medium. Olive oil induced lipase production in all strains, but maximum enzyme yields for some of the strains were also obtained with Tween-80, mineral oil, and glycerol. Partially purified lipases revealed optimal activity at 70-80°C and pH 8-9. Extensive thermal stability studies revealed marked thermostability for the majority of the lipases as well as a two-step thermal deactivation pattern.
BioMed research international. 01/2013; 2013:703130.
[show abstract][hide abstract] ABSTRACT: Marine Protected Areas (MPAs) now form an important part of marine conservation and fisheries management; hence, there is broad interest in developing procedures that optimize their design. We used data collected over a 10-year period (2003–2012) from direct surveys and >100 adult male and female loggerhead sea turtles (Caretta caretta) tracked with devices, includ ing GPS loggers and Fastloc GPS Argos, to consider the optimum design for a MPA at a globally important breeding area, where there is already an existing national marine park aiming to protect the population (Zakynthos, Greece). Turtles primarily used areas very close to shore (approx. 7 km in length by 1 km in width, within the <10 m isobath) for breeding and foraging activity at different times of the year. We calculated that this small nearshore coastal zone encompassed 72% of all turtle GPS locations recorded in the MPA, and is therefore important for conservation management. We developed an index to evaluate the suitability of the existing and proposed conservation zones based on (1) home range area use by turtles in these zones versus (2) zone size, so that the benefit to turtles could be maximized while minimizing the negative impacts to other stakeholders (e.g., boat operators). With this evidence-based approach, we propose a modification to the existing MPA that might both enhance local economic tourism activities and better safeguard this key sea turtle breeding population. The approaches used here will have general application for the design of MPAs used by mobile species that can be tracked.
[show abstract][hide abstract] ABSTRACT: Xanthan gum is a polysaccharide that is widely used as stabilizer and thickener with many industrial applications in food industry. Our aim was to estimate the ability of Xanthomonas campestris ATCC 13951 for the production of xanthan gum by using whey as a growth medium, a by-product of dairy industry. X. campestris ATCC 13951 has been studied in batch cultures using a complex medium for the determination of the optimal concentration of glucose, galactose and lactose. In addition, whey was used under various treatment procedures (de-proteinated, partially hydrolyzed by β-lactamase and partially hydrolyzed and de-proteinated) as culture medium, to study the production of xanthan in a 2 l bioreactor with constant stirring and aeration. A production of 28 g/l was obtained when partially hydrolysed β-lactamase was used, which proved to be one of the highest xanthan gum production reported so far. At the same time, an effort has been made for the control and selection of the most appropriate procedure for the preservation of the strain and its use as inoculant in batch cultures, without loss of its viability and its capability of xanthan gum production. The pre-treatment of whey (whey permeate medium hydrolyzed, WPH) was very important for the production of xanthan by the strain X. campestris ATCC 13951 during batch culture conditions in a 2 l bioreactor. Preservation methods such as lyophilization, cryopreservation at various glycerol solution and temperatures have been examined. The results indicated that the best preservation method for the producing strain X. campestris ATCC 13951 was the lyophilization. Taking into account that whey permeate is a low cost by-product of the dairy industry, the production of xanthan achieved under the studied conditions was considered very promising for industrial application.
MIRCEN Journal of Applied Microbiology and Biotechnology 08/2012; 28(8):2759-64. · 1.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: The biomass degrading enzymatic potential of 101 thermophilic bacterial strains isolated from a volcanic environment (Santorini, Aegean Sea, Greece) was assessed. 80 % of the strains showed xylanolytic activity in Congo Red plates, while only eight could simultaneously hydrolyze cellulose. Fifteen isolates were selected on the basis of their increased enzyme production, the majority of which was identified as Geobacilli through 16S rDNA analysis. In addition, the enzymatic profile was evaluated in liquid cultures using various carbon sources, a procedure that revealed lack of correlation on xylanase levels between the two cultivation modes and the inability of solid CMC cultures to fully unravel the cellulose degrading potential of the isolates. Strain SP24, showing more than 99 % 16S DNA similarity with Geobacillus sp. was further studied for its unique ability to simultaneously exhibit cellulase, xylanase, β-glucosidase and β-xylosidase activities. The first two enzymes were produced mainly extracellularly, while the β-glycosidic activities were primarily detected in the cytosol. Maximum enzyme production by this strain was attained using a combination of wheat bran and xylan in the growth medium. Bioreactor cultures showed that aeration was necessary for both enhanced growth and enzyme production. Aeration had a strong positive effect on cellulase production while it negatively affected expression of β-glucosidase. Xylanase and β-xylosidase production was practically unaffected by aeration levels.
MIRCEN Journal of Applied Microbiology and Biotechnology 06/2012; 28(9):2889-902. · 1.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: The antimicrobial activities of five commercial disinfectants containing quaternary ammonium compound-isopropanol (D1), sodium
methyl dithiocarbamate (D2), sodium thiocarbamate (D3), sodium dimethyl dithiocarbamate (D4) and formaldehyde (D5) were studied
against three main saccharolytic indigenous isolates (Bacillus cereus, Lactobacillus plantarum and Leuconostoc mesenteroides) from a beet sugar extraction line. Preliminary studies suggested that although all the disinfectants were effective against
those isolates, the high economic cost in combination with large amounts of the disinfectants D2, D3 and D4 weaken their possibility
for industrial use. Therefore, the minimum inhibitory concentration (MIC) of the other two examined disinfectants D1 and D5
was determined and survivor curves were obtained, for a period of 7 days. Bacterial counts against time (h) suggested that
D1 was more effective than D5 against the microbial population. In particular, D1 was bacteriolytic above 7 mg/l for B. cereus and bactericidal above 80 mg/l for Lc. mesenteroides and above 100 mg/l for L. plantarum. The disinfectant D5 was bacteriolytic above 25 mg/l for B. cereus and bactericidal above 500 mg/l for Lc. mesenteroides and L. plantarum. Taking into consideration both features, i.e. high concentration and very low cost, the use of D5 (formaldehyde) appeared
more suitable to the concerned beet sugar processor.
World Journal of Microbiology and Biotechnology 04/2012; 20(3):291-296. · 1.26 Impact Factor
[show abstract][hide abstract] ABSTRACT: Two-phase olive-mill waste, the so-called "ecological", has been treated with a Paecilomyces variotii isolate in solid state fermentation experiments. The growth of the microorganism was estimated by measuring the production of carbon dioxide, using gas chromatography. A 46% increase of the protein content was achieved at the fermented product, after molasses addition at the initial mixture. The amino acid profile of the produced protein, as far as the essential amino acids are concerned, was significantly improved, resulting in a product that has the potential to be used as animal feed. Furthermore, it contains lysine, one of the essential amino acids that did not exist at the original product and is produced during fermentation. This is the first report on solid state fermentation of the two-phase olive mill waste (TPOMW) as a substrate, using a Paecilomyces variotii strain.
MIRCEN Journal of Applied Microbiology and Biotechnology 03/2012; 28(3):849-56. · 1.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: We report on the sequence type and beta-lactamase content of 174 carbapenem-resistant Acinetobacter baumannii isolates recovered from clinical specimens during 2010 and 2011 in a tertiary care hospital in central Greece. Carbapenem resistance was associated mainly with carriage of the bla(OXA-23) gene (in 72.4% of the isolates). To our knowledge, this is the first description of A. baumannii strains producing OXA-23 in Greece. During 2011, in our hospital they rapidly ‘replaced’ the previously predominant OXA-58- positive A. baumannii strains.
Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 01/2012; 17(11). · 5.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: The structure of the Bacteria and Archaea community in a large drinking water reservoir (Marathonas, Greece; MR) was investigated in October 2007 and September 2008, using 16S rRNA gene clone libraries. The bacterial communities were more diverse than archaeal communities (Shannon diversity index H' 0.81-3.28 and 1.36-1.77, respectively). The overall bacterial community composition was comparable to bacterioplankton community described in other freshwater habitats. Within the Bacteria, Betaproteobacteria dominated, while representatives of Alpha-, Gamma- and Deltaproteobacteria also occurred. Other important phyla were Actinobacteria and Bacteroidetes, while representatives of Acidobacteria, Cyanobacteria, Chloroflexi, Planctomycetes and Verrucomicrobia were also retrieved. Several phylotypes in Alpha- and Betaproteobacteria and Bacteroidetes were related to bacteria capable of cyanotoxin degradation and with aromatic compounds/iron oxidizers or polymer degraders. Euryarchaeota dominated (60.5%) the Archaea community mostly with phylotypes related to Methanobacteriales and Methanosarcinales. Among the Thaumarchaeota, the two most abundant phylotypes were affiliated (97% similarity) with the only cultivated mesophilic thaumarchaeote of marine origin, Nitrosopumilus maritimus. Temporal and spatial comparison of the prokaryotic community structure revealed that three of the most abundant prokaryotic phylotypes, belonging to Actinobacteria, were recovered from all sites both years, suggesting that these Actinobacteria could be important key players in MR ecosystem functioning.
Microbes and Environments 10/2011; 27(1):1-8. · 2.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: In an effort to increase ethanol productivity during the consolidated bioprocessing (CBP) of lignocellulosics by Fusarium oxysporum, we attempted the constitutive homologous overexpression of one of the key process enzymes, namely an endo-xylanase. The endo-β-1,4-xylanase 2 gene was incorporated into the F. oxysporum genome under the regulation of the gpdA promoter of Aspergillus nidulans. The transformation was effected through Agrobacterium tumefaciens and resulted in 12 transformants, two of which were selected for further study due to their high extracellular xylanase activities under normally repressing conditions (glucose as sole carbon source). During natural induction conditions (growth on xylan) though, the extracellular enzyme levels of the transformants were only marginally higher (5-10%) compared to the wild type despite the significantly stronger xylanase 2 mRNA signals. SDS-PAGE verified enzyme assay results that there was no intracellular xylanase 2 accumulation in the transformants, suggesting the potential regulation in a post transcriptional or translational level. The fermentative performance of the transformants was evaluated and compared to that of the wild type in simple CBP systems using either corn cob or wheat bran as sole carbon sources. Both transformants produced approximately 60% more ethanol compared to the wild type on corn cob, while for wheat bran this picture was repeated for only one of them. This result is attributed to the high extracellular xylanase activities in the transformants' fermentation broths that were maintained 2-2.5-fold higher compared to the wild type.
Journal of biotechnology 01/2011; 152(1-2):16-23. · 2.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Two novel angucyclines were isolated from the streptomycete Acta 1362. The strain was of particular interest regarding the production of characteristic metabolites that were detected by HPLC–diode array profiling of the extracts. Grecocycline A and B were isolated and their structures were determined. Grecocycline A shows cytotoxic activity and grecocycline B inhibits protein tyrosine phosphatase 1B. Moreover, shunt product grecocyline C was isolated and its structure was determined.
European Journal of Organic Chemistry 04/2010; 2010(12):2344-2350. · 3.34 Impact Factor
[show abstract][hide abstract] ABSTRACT: The structure of the cyanobacterial community in a large drinking water reservoir (Marathonas, Greece) was investigated in October 2007 and September 2008. Cyanobacteria-specific primers were used for the PCR amplification of cyanobacterial 16S rDNAs from three water column sites and the water collection tank. In total, 199 clones were sequenced representing 52 unique cyanobacterial, including chloroplast-related, and 11 non-cyanobacterial phylotypes. All cyanobacterial phylotypes belonged to the order Chroococcales. Cluster analysis showed that the cyanobacterial communities in 2007 in the three water column sites showed high similarity between the stations and low diversity (H=1.17-1.44), due to the occurring common phylotypes, while all sites in 2008 had very low similarities between them and higher diversity (H=1.56-2.40). Some of the most abundant phylotypes were closely related (>98%) to members of the genus Gloeocapsa and a potentially toxin-producing strain of Microcystis aeruginosa. The non-cyanobacterial phylotypes were either unaffiliated or belonged to the Verrucomicrobia, and were related with sequences originating from lake water habitats.
Environmental Monitoring and Assessment 03/2010; 173(1-4):155-65. · 1.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: The presence of selected tetracycline resistance (TcR) genes was studied in different Greek seawater habitats, originated from wastewater treatment facilities, fishfarm, and coastal environments. The methods employed included assessment of the presence of twelve gene clusters by PCR, followed by hybridization with specific probes, in habitat extracted DNA, Tc(R) bacteria, and exogenous isolated plasmids conferring TcR. The direct DNA-based analysis showed that tet(A) and tet(K) genes were detected in all habitats, whilst tet(C) and tet(E) were present in fishfarm and wastewater effluent samples and tet(M) was detected in fish-farm and coastal samples. Resistance genes tet(h), tet(C), tet(K), and tet(M) were detected in 60 of the 89 isolates screened. These isolates were identified by fatty acid methyl ester analysis (FAME) as Stenotrophomonas, Acinetobacter, Pseudomonas, Bacillus, and Staphylococcus strains. The presence of the TcR genes in 15% of the bacterial isolates coincided with the presence of IncP plasmids. A habitat-specific dissemination of IncP alpha plasmids in wastewater effluent isolates and of IncP beta plasmids in fishfarm isolates was observed. Exogenous isolation demonstrated the presence of plasmids harbouring Tc(R) genes in all the habitats tested. Plasmids were shown to carry tet(h), tet(C), tet(E), and tet(K) genes. It is concluded that TcR genes are widespread in the seawater habitats studied and often occur on broad host range plasmids that seem to be well disseminated in the bacterial communities.
The Journal of Microbiology 01/2009; 46(6):633-40. · 1.28 Impact Factor