scholarly journals Vibrio anguillarum Is Genetically and Phenotypically Unaffected by Long-Term Continuous Exposure to the Antibacterial Compound Tropodithietic Acid

2016 ◽  
Vol 82 (15) ◽  
pp. 4802-4810 ◽  
Author(s):  
Bastian Barker Rasmussen ◽  
Torben Grotkjær ◽  
Paul W. D'Alvise ◽  
Guangliang Yin ◽  
Faxing Zhang ◽  
...  
Keyword(s):  
Food Production ◽  
Fish Larvae ◽  
Vibrio Anguillarum ◽  
Resistant Bacteria ◽  
Continuous Exposure ◽  
Fish Pathogen ◽  
Content Type ◽  
Tropodithietic Acid ◽  
Antibacterial Compound

ABSTRACTMinimizing the use of antibiotics in the food production chain is essential for limiting the development and spread of antibiotic-resistant bacteria. One alternative intervention strategy is the use of probiotic bacteria, and bacteria of the marineRoseobacterclade are capable of antagonizing fish-pathogenic vibrios in fish larvae and live feed cultures for fish larvae. The antibacterial compound tropodithietic acid (TDA), an antiporter that disrupts the proton motive force, is key in the antibacterial activity of several roseobacters. Introducing probiotics on a larger scale requires understanding of any potential side effects of long-term exposure of the pathogen to the probionts or any compounds they produce. Here we exposed the fish pathogenVibrio anguillarumto TDA for several hundred generations in an adaptive evolution experiment. No tolerance or resistance arose during the 90 days of exposure, and whole-genome sequencing of TDA-exposed lineages and clones revealed few mutational changes, compared to lineages grown without TDA. Amino acid-changing mutations were found in two to six different genes per clone; however, no mutations appeared unique to the TDA-exposed lineages or clones. None of the virulence genes ofV. anguillarumwas affected, and infectivity assays using fish cell lines indicated that the TDA-exposed lineages and clones were less invasive than the wild-type strain. Thus, long-term TDA exposure does not appear to result in TDA resistance and the physiology ofV. anguillarumappears unaffected, supporting the application of TDA-producing roseobacters as probiotics in aquaculture.IMPORTANCEIt is important to limit the use of antibiotics in our food production, to reduce the risk of bacteria developing antibiotic resistance. We showed previously that marine bacteria of theRoseobacterclade can prevent or reduce bacterial diseases in fish larvae, acting as probiotics. Roseobacters produce the antimicrobial compound tropodithietic acid (TDA), and we were concerned regarding whether long-term exposure to this compound could induce resistance or affect the disease-causing ability of the fish pathogen. Therefore, we exposed the fish pathogenVibrio anguillarumto increasing TDA concentrations over 3 months. We did not see the development of any resistance to TDA, and subsequent infection assays revealed that none of the TDA-exposed clones had increased virulence toward fish cells. Hence, this study supports the use of roseobacters as a non-risk-based disease control measure in aquaculture.

scholarly journals Influence of Iron on Production of the Antibacterial Compound Tropodithietic Acid and Its Noninhibitory Analog in Phaeobacter inhibens

2015 ◽  
Vol 82 (2) ◽  
pp. 502-509 ◽  
Author(s):  
Paul W. D'Alvise ◽  
Christopher B. W. Phippen ◽  
Kristian F. Nielsen ◽  
Lone Gram
Keyword(s):  
Mass Spectrometry ◽  
Antibacterial Activity ◽  
High Resolution Mass Spectrometry ◽  
Biologically Active ◽  
Brown Pigment ◽  
Marine Broth ◽  
Content Type ◽  
Tropodithietic Acid ◽  
Antibacterial Compound ◽  
Phaeobacter Inhibens

ABSTRACTTropodithietic acid (TDA) is an antibacterial compound produced by somePhaeobacterandRuegeriaspp. of theRoseobacterclade. TDA production is studied in marine broth or agar since antibacterial activity in other media is not observed. The purpose of this study was to determine how TDA production is influenced by substrate components. High concentrations of ferric citrate, as present in marine broth, or other iron sources were required for production of antibacterially active TDA. However, when supernatants of noninhibitory, low-iron cultures ofPhaeobacter inhibenswere acidified, antibacterial activity was detected in a bioassay. The absence of TDA in nonacidified cultures and the presence of TDA in acidified cultures were verified by liquid chromatography–high-resolution mass spectrometry. A noninhibitory TDA analog (pre-TDA) was produced byP. inhibens,Ruegeria mobilisF1926, andPhaeobactersp. strain 27-4 under low-iron concentrations and was instantaneously converted to TDA when pH was lowered. Production of TDA in the presence of Fe3+coincides with formation of a dark brown substance, which could be precipitated by acid addition. From this brown pigment TDA could be liberated slowly with aqueous ammonia, and both direct-infusion mass spectrometry and elemental analysis indicated a [FeIII(TDA)2]xcomplex. The pigment could also be produced by precipitation of pure TDA with FeCl3. Our results raise questions about how biologically active TDA is produced in natural marine settings where iron is typically limited and whether the affinity of TDA to iron points to a physiological or ecological function of TDA other than as an antibacterial compound.

scholarly journals Species Diversity of Environmental GIM-1-Producing Bacteria Collected during a Long-Term Outbreak

2016 ◽  
Vol 82 (12) ◽  
pp. 3605-3610 ◽  
Author(s):  
Andreas F. Wendel ◽  
Sofija Ressina ◽  
Susanne Kolbe-Busch ◽  
Klaus Pfeffer ◽  
Colin R. MacKenzie
Keyword(s):  
Resistance Genes ◽  
Multidrug Resistant ◽  
Hospital Environment ◽  
Resistant Bacteria ◽  
Environmental Sampling ◽  
Gram Negative Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Gram Negative ◽  
Content Type

ABSTRACTReports of outbreaks concerning carbapenemase-producing Gram-negative bacteria in which the main source of transmission is the hospital environment are increasing. This study describes the results of environmental sampling in a protracted polyspecies metallo-beta-lactamase GIM-1 outbreak driven by plasmids and bacterial clones ofEnterobacter cloacaeandPseudomonas aeruginosain a tertiary care center. Environmental sampling targeting wet locations (especially sinks) was carried out on a surgical intensive care unit and on a medical ward on several occasions in 2012 and 2013. We were able to demonstrate 43blaGIM-1-carrying bacteria (mainly nonfermenters but alsoEnterobacteriaceae) that were either related or unrelated to clinical strains in 30 sinks and one hair washbasin. GIM-1 was found in 12 different species, some of which are described here as carriers of GIM-1. Forty out of 43 bacteria displayed resistance to carbapenems and, in addition, to various non-beta-lactam antibiotics. Colistin resistance was observed in twoE. cloacaeisolates with MICs above 256 mg/liter. TheblaGIM-1gene was harbored in 12 different class 1 integrons, some without the typical 3′ end. TheblaGIM-1gene was localized on plasmids in five isolates.In vitroplasmid transfer by conjugation was successful in one isolate. The environment, with putatively multispecies biofilms, seems to be an important biological niche for multidrug-resistant bacteria and resistance genes. Biofilms may serve as a “melting pot” for horizontal gene transfer, for dissemination into new species, and as a reservoir to propagate future hospital outbreaks.IMPORTANCEIn Gram-negative bacteria, resistance to the clinically relevant broad-spectrum carbapenem antibiotics is a major public health concern. Major reservoirs for these resistant organisms are not only the gastrointestinal tracts of animals and humans but also the (hospital) environment. Due to the difficulty in eradicating biofilm formation in the latter, a sustained dissemination of multidrug-resistant bacteria from the environment can occur. In addition, horizontal transfer of resistance genes on mobile genetic elements within biofilms adds to the total “resistance gene pool” in the environment. To gain insight into the transmission pathways of a rare and locally restricted carbapenemases resistance gene (blaGIM-1), we analyzed the genetic background of theblaGIM-1gene in environmental bacteria during a long-term polyspecies outbreak in a German hospital.

Craft beer – building social terroir through connecting people, place and business

2019 ◽  
Vol 13 (2) ◽  
pp. 149-162 ◽  
Author(s):  
Annelie Sjölander-Lindqvist ◽  
Wilhelm Skoglund ◽  
Daniel Laven
Keyword(s):  
Social Practice ◽  
Food Production ◽  
Design Methodology ◽  
Peripheral Region ◽  
Small Scale ◽  
Research Approach ◽  
Content Type ◽  
Craft Beer ◽  
The Way

Purpose This paper aims to propose the concept of social terroir to help navigate phenomenological and epistemological conditions of small-scale food entrepreneurship. Design/methodology/approach This study used a qualitative research approach and was implemented in the peripheral region of Jämtland in northern Sweden. The study interrogated the ambitions of craft brewers when starting up, their long-term goals and visions, including questions about the reason for starting up a brewery, how the different brewers cooperate and how and why the products are designed and labelled the way they are. Findings This study shows that the production of craft beer is an inherently social practice that is part of a particular sociocultural milieu. This milieu informs production in distinct and interrelated ways: through connecting to place and locality in the different aspects of production and marketing, through cooperation to develop production and overcome barriers, and through embedding their work in sustainability discourses. Originality/value The study addresses how, in the context of craft beer, terroir or taste of place, is a matter of social ties to place and community–social terroir. What is novel is the way in which social terroir becomes a critical ingredient in the production of craft beer. This illustrates how small-scale food production and gastronomic efforts can link people, places and businesses.

scholarly journals Evaluation of Remel Spectra CRE Agar for Detection of Carbapenem-Resistant Bacteria from Rectal Swabs Obtained from Residents of a Long-Term-Care Facility

2015 ◽  
Vol 53 (9) ◽  
pp. 2823-2826 ◽  
Author(s):  
Vincent J. LaBombardi ◽  
Carl M. Urban ◽  
Barry N. Kreiswirth ◽  
Liang Chen ◽  
Giuliana Osorio ◽  
...  
Keyword(s):  
Long Term Care ◽  
Agar Plate ◽  
Care Facility ◽  
Resistant Bacteria ◽  
Term Care ◽  
Content Type ◽  
Term Care Facility ◽  
Long Term Care Facility ◽  
Carbapenem Resistant

We compared the Remel Spectra CRE agar plate to CDC standard methodology for the isolation of carbapenem-resistantEnterobacteriaceae(CRE) from 300 rectal swab specimens obtained from patients residing in a long-term-care facility (LTCF). Multiplex PCR experiments were performed on isolates to identify specificKlebsiella pneumoniaecarbapenemases (KPC) and additional β-lactamases. Of the 300 patients, 72 (24%) harbored CRE and were PCR positive for KPC enzymes. The Remel Spectra CRE plates detected KPC-type CRE in isolates from 70 of 72 patients (97.2%), while the CDC method detected CRE in 56 of 72 (77.8%). CRE identification results were available in 18 h compared to 36 h for the CDC method. Remel Spectra CRE agar plates can provide useful means for a fast and reliable method for detecting KPC-type CRE and for accelerated institution of appropriate infection control precautions.

scholarly journals Quorum Sensing Determines the Choice of Antiphage Defense Strategy in Vibrio anguillarum

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Demeng Tan ◽  
Sine Lo Svenningsen ◽  
Mathias Middelboe
Keyword(s):  
Quorum Sensing ◽  
Cell Density ◽  
Defense Mechanisms ◽  
Vibrio Anguillarum ◽  
Phage Infection ◽  
Phage Resistance ◽  
Fish Pathogen ◽  
Content Type ◽  
Density State ◽  
Infection Pressure

ABSTRACTSelection for phage resistance is a key driver of bacterial diversity and evolution, and phage-host interactions may therefore have strong influence on the genetic and functional dynamics of bacterial communities. In this study, we found that an important, but so far largely overlooked, determinant of the outcome of phage-bacterial encounters in the fish pathogenVibrio anguillarumis bacterial cell-cell communication, known as quorum sensing. Specifically,V. anguillarumPF430-3 cells locked in the low-cell-density state (ΔvanTmutant) express high levels of the phage receptor OmpK, resulting in a high susceptibility to phage KVP40, but achieve protection from infection by enhanced biofilm formation. By contrast, cells locked in the high-cell-density state (ΔvanΟmutant) are almost completely unsusceptible due to quorum-sensing-mediated downregulation of OmpK expression. The phenotypes of the two quorum-sensing mutant strains are accurately reflected in the behavior of wild-typeV. anguillarum, which (i) displays increased OmpK expression in aggregated cells compared to free-living variants in the same culture, (ii) displays a clear inverse correlation betweenompKmRNA levels and the concentration ofN-acylhomoserine lactone quorum-sensing signals in the culture medium, and (iii) survives mainly by one of these two defense mechanisms, rather than by genetic mutation to phage resistance. Taken together, our results demonstrate thatV. anguillarumemploys quorum-sensing information to choose between two complementary antiphage defense strategies. Further, the prevalence of nonmutational defense mechanisms in strain PF430-3 suggests highly flexible adaptations to KVP40 phage infection pressure, possibly allowing the long-term coexistence of phage and host.IMPORTANCEComprehensive knowledge on bacterial antiphage strategies and their regulation is essential for understanding the role of phages as drivers of bacterial evolution and diversity. In an applied context, development of successful phage-based control of bacterial pathogens also requires detailed understanding of the mechanisms of phage protection in pathogenic bacteria. Here, we demonstrate for the first time the presence of quorum-sensing-regulated phage defense mechanisms in the fish pathogenVibrio anguillarumand provide evidence that quorum-sensing regulation allowsV. anguillarumto alternate between different phage protection mechanisms depending on population cell density. Further, our results demonstrate the prevalence of nonmutational defense mechanisms in the investigatedV. anguillarumstrain, which allow flexible adaptations to a dynamic phage infection pressure.

scholarly journals Disruption of Cell-to-Cell Signaling Does Not Abolish the Antagonism of Phaeobacter gallaeciensis toward the Fish Pathogen Vibrio anguillarum in Algal Systems

2013 ◽  
Vol 79 (17) ◽  
pp. 5414-5417 ◽  
Author(s):  
M. J. Prol García ◽  
P. W. D'Alvise ◽  
L. Gram
Keyword(s):  
Quorum Sensing ◽  
Cell Signaling ◽  
Disease Control ◽  
Vibrio Anguillarum ◽  
Fish Pathogen ◽  
Wild Type ◽  
Content Type ◽  
Phaeobacter Gallaeciensis ◽  
Algal Cultures

ABSTRACTQuorum sensing (QS) regulatesPhaeobacter gallaeciensisantagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reducedVibrio anguillarumto the same extent as the wild type. Consequently, a combination of probioticPhaeobacterand QS inhibitors is a feasible strategy for aquaculture disease control.

scholarly journals A Novel Method for Sampling and Long-Term Monitoring of Microbes That Uses Stickers of Plain Paper

2019 ◽  
Vol 85 (14) ◽  
Author(s):  
Martin Bobal ◽  
Anna Kristina Witte ◽  
Patrick Mester ◽  
Susanne Fister ◽  
Dagmar Schoder ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Quantitative Pcr ◽  
Food Production ◽  
Cost Effective ◽  
Sampling System ◽  
Content Type ◽  
Long Term Monitoring ◽  
Production Areas ◽  
Term Monitoring

ABSTRACT Detection of pathogens is crucial in food production areas. While it is well established, swabbing as a state-of-the-art sampling method offers several drawbacks with respect to yield, standardization, overall handling, and long-term monitoring. This led us to develop and evaluate a method that is easier to use at a lower cost and that should be at least as sensitive. After evaluating sundry promising materials, we tested text-marking paper stickers for their suitability to take up and release Listeria monocytogenes with their nonsticky paper side over a 14-day time period using quantitative PCR. The recovery rate was similar to that in previous studies using conventional swabs, and we also confirmed the feasibility of pooling besides resilience to cleansing and disinfection. In a proof-of-concept experiment that sampled several locations, such as door handles, the occurrences of L. monocytogenes and Escherichia coli were determined. The results suggest that the presented sticker system might offer a promising cost-effective alternative sampling system with improved handling characteristics. IMPORTANCE As a ubiquitous bacterium, Listeria monocytogenes has a propensity to enter food production areas inadvertently via fomites such as door handles and switches. While the bacterium might not be in direct contact with the food products, knowing the microbial status of the surroundings is essential for risk assessment. Our investigation into a novel quantitative PCR (qPCR)-based sampling system with the highest sensitivity and ability to monitor over long periods of time, yet based on paper, proved to be cost-effective and reasonably convenient to handle.

scholarly journals Vibriophages and Their Interactions with the Fish Pathogen Vibrio anguillarum

2014 ◽  
Vol 80 (10) ◽  
pp. 3128-3140 ◽  
Author(s):  
Demeng Tan ◽  
Lone Gram ◽  
Mathias Middelboe
Keyword(s):  
Vibrio Anguillarum ◽  
Fish Pathogen ◽  
Phenotypic Properties ◽  
Content Type ◽  
Host Interaction ◽  
Individual Host ◽  
Potential Development ◽  
The Individual ◽  
Susceptibility Patterns ◽  
Rapid Regrowth

ABSTRACTVibrio anguillarumis an important pathogen in aquaculture, responsible for the disease vibriosis in many fish and invertebrate species. Disease control by antibiotics is a concern due to potential development and spread of antibiotic resistance. The use of bacteriophages to control the pathogen may offer a non-antibiotic-based approach to reduce vibriosis. A detailed understanding of the phage-host interaction is needed to evaluate the potential of phages to control the pathogen. In this study, we examined the diversity and interactions of 11 vibriophages, 24V. anguillarumstrains, and 13Vibriospecies strains. Together, the host ranges of the 11 phages covered all of the tested 37Vibriosp. host strains, which represented considerable temporal (20 years) and geographical (9 countries) differences in their origins of isolation. Thus, despite the occurrence of unique susceptibility patterns of the individual host isolates, key phenotypic properties related to phage susceptibility are distributed worldwide and maintained in the globalVibriocommunity for decades. The phage susceptibility pattern of the isolates did not show any relation to the physiological relationships obtained from Biolog GN2 profiles, demonstrating that similar phage susceptibility patterns occur across broad phylogenetic and physiological differences inVibriostrains. Subsequent culture experiments with two phages and twoV. anguillarumhosts demonstrated an initial strong lytic potential of the phages. However, rapid regrowth of both phage-resistant and phage-sensitive cells following the initial lysis suggested that several mechanisms of protection against phage infection had developed in the host populations.

scholarly journals Persistent Legionnaires’ Disease and Associated Antibiotic Treatment Engender a Highly Disturbed Pulmonary Microbiome Enriched in Opportunistic Microorganisms

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Ana Elena Pérez-Cobas ◽  
Christophe Ginevra ◽  
Christophe Rusniok ◽  
Sophie Jarraud ◽  
Carmen Buchrieser
Keyword(s):  
Antibiotic Treatment ◽  
Legionella Pneumophila ◽  
Antimicrobial Treatment ◽  
Resistant Bacteria ◽  
Marker Genes ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Lung Microbiome ◽  
Long Term Treatment

ABSTRACT Despite the importance of pneumonia to public health, little is known about the composition of the lung microbiome during infectious diseases, such as pneumonia, and how it evolves during antibiotic therapy. To study the possible relation of the pulmonary microbiome to the severity and outcome of this respiratory disease, we analyzed the dynamics of the pathogen and the human lung microbiome during persistent infections caused by the bacterium Legionella pneumophila and their evolution during antimicrobial treatment. We collected 10 bronchoalveolar lavage fluid samples from three patients during long-term hospitalization due to pneumonia and performed a unique longitudinal study of the interkingdom microbiome, analyzing the samples for presence of bacteria, archaea, fungi, and protozoa by high-throughput Illumina sequencing of marker genes. The lung microbiome of the patients was characterized by a strong predominance of the pathogen, a low diversity of the bacterial fraction, and an increased presence of opportunistic microorganisms. The fungal fraction was more stable than the bacterial fraction. During long-term treatment, no genomic changes or antibiotic resistance-associated mutations that could explain the persistent infection occurred, according to whole-genome sequencing analyses of the pathogen. After antibiotic treatment, the microbiome did not recover rapidly but was mainly constituted of antibiotic-resistant species and enriched in bacteria, archaea, fungi, or protozoa associated with pathogenicity. The lung microbiome seems to contribute to nonresolving Legionella pneumonia, as it is strongly disturbed during infection and enriched in opportunistic and/or antibiotic-resistant bacteria and microorganisms, including fungi, archaea, and protozoa that are often associated with infections. IMPORTANCE The composition and dynamics of the lung microbiome during pneumonia are not known, although the lung microbiome might influence the severity and outcome of this infectious disease, similar to what was shown for the microbiome at other body sites. Here we report the findings of a comprehensive analysis of the lung microbiome composition of three patients with long-term pneumonia due to L. pneumophila and its evolution during antibiotic treatment. This work adds to our understanding of how the microbiome changes during disease and antibiotic treatment and points to microorganisms and their interactions that might be beneficial. In addition to bacteria and fungi, our analyses included archaea and eukaryotes (protozoa), showing that both are present in the pulmonary microbiota and that they might also play a role in the response to the microbiome disturbance.

scholarly journals Sublethal Ciprofloxacin Treatment Leads to Rapid Development of High-Level Ciprofloxacin Resistance during Long-Term Experimental Evolution of Pseudomonas aeruginosa

2013 ◽  
Vol 57 (9) ◽  
pp. 4215-4221 ◽  
Author(s):  
Karin Meinike Jørgensen ◽  
Tina Wassermann ◽  
Peter Østrup Jensen ◽  
Wang Hengzuang ◽  
Søren Molin ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Rapid Development ◽  
Bacterial Flora ◽  
Cross Resistance ◽  
Resistant Bacteria ◽  
Bacterial Populations ◽  
Content Type ◽  
Ciprofloxacin Resistance ◽  
High Level

ABSTRACTThe dynamics of occurrence and the genetic basis of ciprofloxacin resistance were studied in a long-term evolution experiment (940 generations) in wild-type, reference strain (PAO1) and hypermutable (PAOΔmutS and PAOMY-Mgm)P. aeruginosapopulations continuously exposed to sub-MICs (1/4) of ciprofloxacin. A rapid occurrence of ciprofloxacin-resistant mutants (MIC of ≥12 μg/ml, representing 100 times the MIC of the original population) were observed in all ciprofloxacin-exposed lineages of PAOΔmutS and PAOMY-Mgm populations after 100 and 170 generations, respectively, and in one of the PAO1 lineages after 240 generations. The genetic basis of resistance was mutations ingyrA(C248T and G259T) andgyrB(C1397A). Cross-resistance to beta-lactam antibiotics was observed in the bacterial populations that evolved during exposure to sublethal concentrations of ciprofloxacin. Our study shows that mutants with high-level ciprofloxacin resistance are selected inP. aeruginosabacterial populations exposed to sub-MICs of ciprofloxacin. This can have implications for the long-term persistence of resistant bacteria and spread of antibiotic resistance by exposure of commensal bacterial flora to low antibiotic concentrations.

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