A bacterial quorum-sensing precursor induces mortality in the marine coccolithophore, Emiliania huxleyi

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 7 (2016): 59, doi:10.3389/fmicb.2016.00059.Interactions between phytoplankton and bacteria play a central role in mediating biogeochemical cycling and food web structure in the ocean. However, deciphering the chemical drivers of these interspecies interactions remains challenging. Here, we report the isolation of 2-heptyl-4-quinolone (HHQ), released by Pseudoalteromonas piscicida, a marine gamma-proteobacteria previously reported to induce phytoplankton mortality through a hitherto unknown algicidal mechanism. HHQ functions as both an antibiotic and a bacterial signaling molecule in cell–cell communication in clinical infection models. Co-culture of the bloom-forming coccolithophore, Emiliania huxleyi with both live P. piscicida and cell-free filtrates caused a significant decrease in algal growth. Investigations of the P. piscicida exometabolome revealed HHQ, at nanomolar concentrations, induced mortality in three strains of E. huxleyi. Mortality of E. huxleyi in response to HHQ occurred slowly, implying static growth rather than a singular loss event (e.g., rapid cell lysis). In contrast, the marine chlorophyte, Dunaliella tertiolecta and diatom, Phaeodactylum tricornutum were unaffected by HHQ exposures. These results suggest that HHQ mediates the type of inter-domain interactions that cause shifts in phytoplankton population dynamics. These chemically mediated interactions, and other like it, ultimately influence large-scale oceanographic processes.This research was support through funding from the Gordon and Betty Moore Foundation through Grant GBMF3301 to MJ and TM; NIH grant from the National Institute of Allergy and Infectious Disease (NIAID – 1R21Al119311-01) to TM and KW; the National Science Foundation (OCE – 1313747) and US National Institute of Environmental Health Science (P01-ES021921) through the Oceans and Human Health Program to BM. Additional financial support was provided to TM from the Flatley Discovery Lab

Prevalence and antimicrobial susceptibility of Enterococcus spp. in ready-to-eat salads (dips), the environment and the personnel of a salad processing plant in Northern Greece

Διακόσια εικοσιπέντε δείγματα από τις σαλάτες (τυροσαλάτα, ταραμοσαλάτα, μελιτζανοσαλάτα και τζατζίκι),το περιβάλλον και το προσωπικό ενός εργοστασίου παραγωγής σαλατών στην Βόρεια Ελλάδα εξετάστηκαν για την παρουσίατων Enterococccus spp. και την αντιμικροβιακή αντοχή τους. Απομονώθηκε Enterococcus faecium σε ποσοστό 12% τωνδειγμάτων. Ποσοστά 38,1% και 15% των δειγμάτων μελιτζανοσαλάτας και τυροσαλάτας, αντίστοιχα, ήταν θετικά. Τα ποσοστάαπομόνωσης από τα συστατικά των σαλατών ήταν 30% για τη μαγιονέζα, 20% για τη φέτα και 10% για τη μυζήθρα. Θετικάήταν, επίσης, 8,6% των δειγμάτων από το περιβάλλον, 20% από τις ποδιές, 20% από τα γάντια και 16,7% από τις ρινικέςκοιλότητες των εργαζομένων. Όλα τα απομονωθεντα στελέχη ήταν ευαίσθητα στα γλυκοπεπτίδια (βανκομυκίνη καιτεϊκοπλανίνη).Τα δυο απομονωθεντα στελέχη από τις ρινικές κοιλότητες των εργαζομένων ήταν ανθεκτικά στην πενικιλλίνη και τηναμπικιλλίνη, ενώ ένα από αυτά ήταν επιπλέον ανθεκτικό στη χλωραμφενικόλη. Όλα τα στελέχη που απομονώθηκαν από τοπεριβάλλον, τις σαλάτες και τα συστατικά τους ήταν ευαίσθητα στα τρία αυτά αντιβιοτικά, αλλά παρουσίασαν αντοχή σεπερισσότερες των τριών κατηγορίες αντιβιοτικών. Τα έτοιμα προς κατανάλωση τρόφιμα μπορεί να είναι δυνητικές πηγέςμόλυνσης του ανθρώπου με πολυναθεκτικοΰς στα αντιβιοτικά εντερόκοκους.A total of 225 samples from the dips (cheese, roe, egg plant and tzatziki dip), the environment and the handlers of a salad manufacturing plant in Northern Greece were examined for the presence and antibiotic susceptibility of Entervcocccus spp. Enterococcus faecium was the isolated species from 12% of the samples. 38.1% and 15% of egg plant and cheese dip samples were positive, respectively. Among the dip ingredients, 30% of mayonnaise, 20% of feta cheese and 10% of myzithra were positive. Positive were, also, 8.6 % of the environmental samples, 20% from handlers' skirts, 20% from handlers' gloves and 16.7% from their nasal cavity. All isolates were sensitive to glycopeptides (vancomycin and teicoplanin). Isolates from handlers' nasal cavities were resistant to penicillin and ampicillin, while one of them was, also, resistant to chloramphenicol. All isolates from the environment, the dips and their ingredients were susceptible to these three antibiotics, but they presented resistance to more than 3 antibiotic categories. Ready-to-eat foods may be potential source of contamination to humans of multidrug resistant enterococci. Further research is needed to elucidate their epidemiology in these foods.

Microbiological hazards at several stages of production and distribution of cooked sausages

Εξετάσθηκαν 51 δείγματα κρεατοπαστών διαφόρων ειδών αλλαντικών θερμικής επεξεργασίας από δυο αλλαντοβιομηχανίες της Β. Ελλάδας. Η ολική μεσόφιλη χλωρίδα (ΟΜΧ) των κρεατοπαστών αυτών κυμαινόταν 5,3-6,3 Log10CFU/g. Στα ίδια δείγματα παρατηρήθηκε σταθερή η παρουσία σημαντικού αριθμού κολοβακτηριοειδών (93->2.400MPN/g) και οξυγαλακτικών βακτηρίων (5-6,3 Log10CFU/g). Η L. monocytogenes ανιχνεύθηκε σε ποσοστό 56 και 38,4% των δειγμάτων από κάθε αλλαντοβιομηχανία αντιστοίχως. Η E. coli ανιχνεύθηκε σε ποσοστό 20 και 16,6% και η Salmonella spp σε 12 και 16,6% αντιστοίχως. Μετά τη θερμική επεξεργασία των κρεατοπαστών για την παραγωγή των αλλαντικών, σε κανένα δείγμα δεν διαπιστώθηκε η παρουσία των προαναφερθέντων παθογόνων βακτηρίων ούτε και η επιβίωση κολοβακτηριοειδών. Δεν παρατηρήθηκε, επίσης, ανάνηψη τυχόν τραυματισμένων κυττάρων τους μετά τη συντήρηση των ίδιων αλλαντικών σε θερμοκρασία 4°C επί 20 ημέρες. Η ΟΜΧ των αλλαντικών, αμέσως μετά τη θερμική επεξεργασία, κυμάνθηκε 3-4,7Log10CFU/g και αποτελούνταν κυρίως από οξυγαλακτικά (<2-4,5 Log10CFU/g) και σπορογόνα (3-4,5 Log10CFU/g ). Μετά τη συντήρηση των αλλαντικών αυτών στους 4°C επί 20 ημέρες σε κενό, παρατηρήθηκε αύξηση της ΟΜΧ και των οξυγαλακτικών, η οποία σε καμιά περίπτωση δεν ξεπέρασε τον lLog1 0 . Εξετάσθηκαν επίσης από 16 δείγματα από την επιφάνεια και το εσωτερικό μη ενθηκευμένων αλλαντικών θερμικής επεξεργασίας, τα οποία αποτελούνται από μεγάλα ή αυτοτελή τεμάχια κρέατος. Διαπιστώθηκε ότι η ΟΜΧ των δειγμάτων αυτών από τις επιφάνειες κυμαινόταν 5-5,3 Log10CFU/g , ενώ τα δείγματα από το εσωτερικό 2-3,5 Log10CFU/g. Κολοβακτηριοειδή, E. coli, L. monocytogenes, και Salmonella spp δεν ανιχνεύθηκαν. Κυρίαρχη χλωρίδα ήταν τα οξυγαλακτικά βακτήρια. Εξετάσθηκαν επίσης δείγματα από τις επιφάνειες μη ενθηκευμένων αλλαντικών, κατά τις διάφορες φάσεις, από τη θερμική επεξεργασία έως τη συντήρηση τους υπό ψύξη επί 24 ώρες, χωρίς προστατευτική συσκευασία. Η εξέταση έδειξε ότι η ΟΜΧ στην επιφάνεια των αλλαντικών αυτών προέρχεται κυρίως από το περιβάλλον και το νερό των καταιονητήρων ψύξης. Η ΟΜΧ, αμέσως μετά τη θερμική επεξεργασία, ήταν <2 Log10CFU/g, μετά την ψυξη με νερό ήταν 3 Log10CFU/g και μετά 24 ώρες συντήρησης ήταν 3 Log10CFU/g. Στα δείγματα των αλλαντικών μετά τη συντήρηση τους επί 24 ώρες διαπιστώθηκε και η παρουσία κολοβακτηριοειδών. Σε δείγματα μάλιστα αλλαντικών ορισμένων ημερών ο πληθυσμός των κολοβακτηριοειδών ήταν >2.400 MPN/g. Εξετάσθηκαν επίσης 69 δείγματα από τις επιφάνειες του εξοπλισμού τεμαχισμού και συσκευασίας βραστών αλλαντικών τριών αλλαντοβιομηχανιών και 28 δείγματα από τον αντίστοιχο εξοπλισμό 12 καταστημάτων λιανικής πώλησης τροφίμων. L. monocytogenes απομονώθηκε σε ποσοστό 6 και 14,2% των δειγμάτων που προερχόταν από τα μαχαίρια των μηχανών τεμαχισμού των αλλαντοβιομηχανιών και των καταστημάτων λιανικής πώλησης αντιστοίχως. Τα αποτελέσματα αυτά δείχνουν τη σημασία εφαρμογής των κανόνων ορθής υγιεινής πρακτικής, ιδιαίτερα μετά τη θερμική επεξεργασία, στην παραγωγή και διάθεση των αλλαντικών θερμικής επεξεργασίας, για την αποφυγή της μόλυνσης από παθογόνα βακτήρια και την αύξηση των σαπροφυτικών που περιορίζουν το χρόνο ζωής τους.Fifty one (51) samples of several types of cooked sausage paste, prepared by two meat factories in N. Greece were examined. TPC of these samples ranged between 5,3-6,3 Log10CFU/g. Coliforms were regularly present reaching populations of 93->2.400 MPN/g and lactic acid bacteria ranged between 5-6,3 Log10CFU/g. L. monocytogenes was detected in 56 and 38,4% of the samples collected in each factory. E. coli was detected in 20 and 16,6%, and Salmonella spp in 12 and 16,6% respectively. Neither pathogens nor coliforms were detected in 51 samples of cooked sausages originated from the same pastes examined before. No recovery of any injured cells of the pathogenic bacteria and coliforms was observed after their storage at 4°C for 20 days. TPC of the cooked sausage samples, after thermal treatment, ranged between 3-4,7 Log10CFU/g and consisted mainly of lactic acid bacteria (range <2-4,5 Log10CFU/g) and sporeformers (range 3-4,5 Log10CFU/g). After 20 days storage at 4°C the TPC and lactid acid bacteria counts of the cooked sausages, increased by <1 Log. We also examined 16 surface and center samples of cooked sausages and meat products without casings, consisting of big meat pieces (bacon, smoked ham,etc). Surface TPC ranged between 5-5,3 Log10CFU/g and from the center of the meats they ranged between 2-3,5 Log1 0CFU/g. Coliforms, E. coli, L. monocytogenes and Salmonella spp were not detected. Lactic acid bacteria were the main flora. Furthermore we examined surface samples of cooked meat products, without casings, during several stages following thermal treatment and up to storage for 24 h at 4° C, without any protective package. TPC immediately after thermal treatment were <2 Log^CFU/g, after cooling with water increased they increased at 3 Log10CFU/g and remained the same during the following 24 h storage at 4°C. Coliforms were detected in the stored products. Their populations exceeded 2.400 MPN/g on the surface of the samples after storage for a few days at 4°C. It is assumed that the flora on the surface of these products originated from the environment and the cooling water. Finally we examined 69 samples from surfaces of the slicing and packaging equipment of cooked meat products in 3 meat factories and 28 samples from 12 super markets. L. monocytogenes was detected in 6 and 14,2% of the samples that originated from the slicing blades in the factories and super markets respectively. The results of this study underline the importance of GMP for the prevention of contamination of cooked sausages with pathogens and the control of the growth of the spoilage bacteria population which minimize the self life of these products. This is especially true after thermal treatment during peeling and slicing

Prevalence of Listeria spp. in freshwater T\s\v(Oncorhynchus my kiss and Carassius gibelio) and the environment offish markets in Northern Greece

Στην παρούσα μελέτη, 405 συνολικά δείγματα από ψάρια του γλυκού νερού, το προσωπικό και το περιβάλλον ιχθυοπωλείων τριών πόλεων της Β. Ελλάδας εξετάστηκαν για την παρουσία των Listeria spp. Τα δείγματα αυτά ελήφθησαν136 από την επιδερμίδα και 136 από τη σάρκα 71 πεστρόφων (Oncorhynchus mykiss) και 65 κυπρίνων (Carassius gibelio), 20 από τα χέρια του προσωπικού, 27 από τα μαχαίρια, 22 από τις επιφάνειες εργασίας, 29 από ξύλινες κάσες, 15 από πλαστικέςκάσες, 18 από τα δάπεδα και 2 από καπάκια αποχετεύσεων. Listeria spp. απομονώθηκαν σε ποσοστό 10,62% των δειγμάτων,εκ των οποίων 0,99% ήταν L. monocytogenes, 6,69% L. seeligeri και 4,943% L. innocua, αντιστοίχως. L. Monocytogenes απομονώθηκε σε ποσοστό 3,54% των δειγμάτων του περιβάλλοντος και σε κανένα από τα δείγματα των ψαριών του γλυκού νερού και των χεριών του προσωπικού. Listeria spp. απομονώθηκε σε ποσοστό 1,54% των δειγμάτων από τη σάρκα των κυπρίνων (1,54% L. seeligeri), 18.46% των δειγμάτων από την επιδερμίδα των κυπρίνων (10,77% L. seeligeri και 7,69% L.innocua) και 8,45% των δειγμάτων από την επιδερμίδα των πεστρόφων (1,41% L. seeligeri και 7,04% L. innocua). Το υψηλότερο ποσοστό απομόνωσης των Listeria spp. από τα δείγματα του περιβάλλοντος τονίζουν τη σημασία των συνθηκών υγιεινής ώστε να ελαττωθεί ο κίνδυνος μόλυνσης με L. monocytogenes στο επίπεδο λιανικής πώλησης.In this study, a total of 405 samples from freshwater fish, personnel and environment were collected from retail fish markets in three cities in Northern Greece and they were examined for the presence of Listeria spp. They consisted of 136 samples from the skin and 136 from the flesh of 71 rainbow trout (Oncorhynchus mykiss) and 65 gibel carps (Carassius gibelio), 20 from workers' hands, 27 from workers' knives, 22 from working surfaces, 29 from wooden boxes, 15 from plastic boxes, 18 from floor surfaces and 2 from drainage lids. Listeria spp. was isolated from 10.62% of the samples, L. monocytogenes were 0.99%, 4.69% L. seeligeri and 4.94% L. innocua, respectively. L. monocytogenes was isolated from 3.54% of the environmental samples and none from fresh water fish and workers hands' samples. Listeria spp. was isolated from 1.54% of gibel carp flesh (1.54% L. seeligeri), from 18.46% of gibel carp skin (10.77% L. seeligeri and 7.69% L. innocua) and from 8.45% from rainbow trout skin samples (1.41% L. seeligeri and 7.04% L. innocua). The higher rate of isolation of Listeria spp. from the environmental samples emphasises the importance of sanitary conditions in order to reduce the risk of contamination by L. monocytogenes at the retail level

1,8-Cineole Inhibits Both Proliferation and Elongation of BY-2 Cultured Tobacco Cells

Volatile monoterpenes such as 1,8-cineole inhibit the growth of Brassica campestris seedlings in a dose-dependent manner, and the growth-inhibitory effects are more severe for roots than hypocotyls. The preferential inhibition of root growth may be explained if the compounds inhibit cell proliferation more severely than cell elongation because root growth requires both elongation and proliferation of the constituent cells, whereas hypocotyl growth depends exclusively on elongation of existing cells. In order to examine this possibility, BY-2 suspension-cultured tobacco (Nicotiana tabacum) cells were treated with 1,8-cineole, and the inhibitory effects on cell proliferation and on cell elongation were assessed quantitatively. Treatment with 1,8-cineole lowered both the mitotic index and elongation of the cells in a dose-dependent manner, and the half-maximal inhibitory concentration (IC50) for cell elongation was lower than that for cell proliferation. Moreover, 1,8-cineole also inhibited starch synthesis, with IC50 lower than that for cell proliferation. Thus, the inhibitory effects of 1,8-cineole were not specific to cell proliferation; rather, 1,8-cineole seemed inhibitory to a variety of physiological activities when it was in direct contact with target cells. Based on these results, possible mechanisms for the mode of action of 1,8-cineole and for its preferential inhibition on root growth are discussed

Antibiotic sensitivity profile of Salmonella isolated from two slaughterhouses and human clinical cases

The antibiotic sensitivity of Salmonella strains isolated during the period 1996-98 from two industrial slaughterhouses of Northern Greece was detennined and compared with that of salmonellae isolated from human hospital cases during the period 1995-1997. For antibiotic sensitivity the disc agar diffusion method was used. Of 1874 samples obtained from the slaughterhouse environment (floors, worker\u27s hands and their knives), pork carcasses, by-products (livers and plucks) as well as lymph nodes and caecal contents 178 (9.5%) were positive for Salmonella spp. The salmonellae belonged to 22 serotypes. S. derby, S. london and S. typhimurium represented 25.8%, 15.2%, and 10.7% of the serotypes respectively. Of the salmonellae 59%, and 4.5%, were resistant and 33%, and 4.5% were intermediate sensitive to Tetracyclin, and Streptomycin, respectively and 26.4%, 14.6%, 5.1%, 1.7% and 1% were resistant to Ampicillin, Sulfamethoxa\u3eole I Trimethoprim, Chloramphenicol, Gentamicin, and Tobramycin respectively. Of the S. typhimurium strains 47% were resistant to Ampicillin and 41.2% to Chloramphenicol. Seven of the 19 strains were DT I 04, isolated for the first time in Greece, and multiple drug resistant. Of all isolates 5.1% were resistant to Chloramphenicol, the use of which is prohibited in food animal veterinary practice. Of the 422 salmonellae isolated at the Hospital of Infectious Diseases in Thessaloniki during the period 1996-98 77.4% were S. enteritidis and 17.7% S. typhimurium. Of the salmonellae isolated during 1995-1997, 76-79 % were resistant to Ampicillin and 1.2-1.5% to Chloramphenicol. Many of S. typhimurium strains isolated from the slaughterhouses and human cases exhibited the same antibiotic sensitivity profile a fact indicative of a potential transfer of animal strains to humans. Salmonellae of the same serotype exhibited different antibiotic resistance profiles, an indication of the presence of different clones within the same serotype. No S. enteritidis was isolated in slaughterhouses

Radiotherapy as nose preservation treatment strategy for cancer of the nasal vestibule:the Dutch experience

Contains fulltext : 238459.pdf (Publisher’s version ) (Open Access

The Prognostic Value of Baseline 18F-FDG PET/CT in Human Papillomavirus-Positive Versus Human Papillomavirus-Negative Patients with Oropharyngeal Cancer

Purpose:Oropharynx cancer (OPC) is heterogeneous; human papillomavirus (HPV)-positive and HPV- tumors represent 2 disease entities with a different prognosis. Earlier studies investigating the prognostic value of pretreatment 18F-FDG PET in OPC are small or included patients with unknown HPV status. This study assessed the prognostic value of PET variables, in a large cohort with balanced HPV status. Methods: Retrospectively, primary tumor SUVmax, SUVpeak, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were extracted from baseline FDG PET/CT of patients with OPC treated with (chemo)radiation. The Pearson correlation between the PET variables was calculated. With linear regression, the correlation between the PET variables and HPV status, age, smoking status, T stage, N stage, and American Joint Committee on Cancer stage was calculated. Univariable and multivariable Cox models analyzed local control, overall survival, and disease-free survival (DFS). Results:Of 201 patients, 109 were HPV+. Metabolic tumor volume and TLG correlated (r = 0.96), as did SUVpeak and SUVmax (r = 0.97). The PET variables correlated strongest with HPV status and T stage. These two accounted for 40% of the variance of MTV and 33% of TLG. Human papillomavirus-negative tumors had a significantly higher SUVmax, SUVpeak, MTV, and TLG. In univariable analysis, all PET variables were significantly associated with local control, overall survival, and DFS. In multivariable analysis, TLG was significantly associated to DFS in patients with HPV- OPC (hazard ratio, 1.005; 95% confidence interval, 1.001-1.010; P = 0.03). However, we did not observe this in HPV+ patients. Conclusions: Increased baseline TLG is associated with worse DFS in HPV- OPC and might be used as biomarker for risk stratification in these patients. Interestingly, we could not identify this association in HPV+ patients.</p