Bacteriophage T4 Infection of Stationary Phase E. coli: Life after Log from a Phage Perspective

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Elizabeth Martin Kutter

2016-09-01

Full Text Available Virtually all studies of phage infections investigate bacteria growing exponentially in rich media. In nature, however, phages largely encounter non-growing cells. Bacteria entering stationary phase often activate well-studied stress defense mechanisms that drastically alter the cell, facilitating its long-term survival. An understanding of phage-host interactions in such conditions is of major importance from both an ecological and therapeutic standpoint. Here, we show that bacteriophage T4 can efficiently bind to, infect and kill E. coli in stationary phase, both in the presence and absence of a functional stationary-phase sigma factor, and explore the response of T4-infected stationary phase cells to the addition of fresh nutrients 5 or 24 hours after that infection. An unexpected new mode of response has been identified. Hibernation mode is a persistent but reversible dormant state in which the infected cells make at least some phage enzymes, but halt phage development until appropriate nutrients become available before producing phage particles. Our evidence indicates that the block in hibernation mode occurs after the middle-mode stage of phage development; host DNA breakdown and the incorporation of the released nucleotides into phage DNA indicate that the enzymes of the nucleotide synthesizing complex, under middle-mode control, have been made and assembled into a functional state. Once fresh glucose and amino acids become available, the standard lytic infection process rapidly resumes and concentrations of up to 1011 progeny phage (an average of about 40 phage per initially-present cell are produced. All evidence is consistent with the hibernation-mode control point lying between middle mode and late mode T4 gene expression. We have also observed a scavenger response, where the infecting phage takes advantage of whatever few nutrients are available to produce small quantities of progeny within 2 to 5 hours after infection. The scavenger

Transcriptome Analysis of a Bloom-Forming Cyanobacterium Microcystis aeruginosa during Ma-LMM01 Phage Infection

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Daichi Morimoto

2018-01-01

Full Text Available Microcystis aeruginosa forms massive blooms in eutrophic freshwaters, where it is constantly exposed to lytic cyanophages. Unlike other marine cyanobacteria, M. aeruginosa possess remarkably abundant and diverse potential antiviral defense genes. Interestingly, T4-like cyanophage Ma-LMM01, which is the sole cultured lytic cyanophage infecting M. aeruginosa, lacks the host-derived genes involved in maintaining host photosynthesis and directing host metabolism that are abundant in other marine cyanophages. Based on genomic comparisons with closely related cyanobacteria and their phages, Ma-LMM01 is predicted to employ a novel infection program that differs from that of other marine cyanophages. Here, we used RNA-seq technology and in silico analysis to examine transcriptional dynamics during Ma-LMM01 infection to reveal host transcriptional responses to phage infection, and to elucidate the infection program used by Ma-LMM01 to avoid the highly abundant host defense systems. Phage-derived reads increased only slightly at 1 h post-infection, but significantly increased from 16% of total cellular reads at 3 h post-infection to 33% of all reads by 6 h post-infection. Strikingly, almost none of the host genes (0.17% showed a significant change in expression during infection. However, like other lytic dsDNA phages, including marine cyanophages, phage gene dynamics revealed three expression classes: early (host-takeover, middle (replication, and late (virion morphogenesis. The early genes were concentrated in a single ∼5.8-kb window spanning 10 open reading frames (gp054–gp063 on the phage genome. None of the early genes showed homology to the early genes of other T4-like phages, including known marine cyanophages. Bacterial RNA polymerase (σ70 recognition sequences were also found in the upstream region of middle and late genes, whereas phage-specific motifs were not found. Our findings suggest that unlike other known T4-like phages, Ma-LMM01

Bacteria, phages and septicemia.

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Ausra Gaidelyte

Full Text Available The use of phages is an attractive option to battle antibiotic resistant bacteria in certain bacterial infections, but the role of phage ecology in bacterial infections is obscure. Here we surveyed the phage ecology in septicemia, the most severe type of bacterial infection. We observed that the majority of the bacterial isolates from septicemia patients spontaneously secreted phages active against other isolates of the same bacterial strain, but not to the strain causing the disease. Such phages were also detected in the initial blood cultures, indicating that phages are circulating in the blood at the onset of sepsis. The fact that most of the septicemic bacterial isolates carry functional prophages suggests an active role of phages in bacterial infections. Apparently, prophages present in sepsis-causing bacterial clones play a role in clonal selection during bacterial invasion.

Genomic Characterization of a Novel Phage Found in Black Abalone (Haliotis cracherodii) Infected with Withering Syndrome

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Closek, C. J.; Langevin, S.; Burge, C. A.; Crosson, L.; White, S.; Friedman, C. S.

2016-02-01

Withering syndrome (WS), caused by the bacterium Candidatus Xenohaliotis californiensis, a Rickettsia-like organism (RLO), infects many species of abalone. Black abalone (Haliotis cracherodii), one of two endangered species of abalone, has experienced high population losses along the California coast due to WS. Recently, we observed reduced pathogenicity and mortality events in RLO-infected abalone when a novel bacteriophage (phage) was also present. To better understand phage-bacterium dynamics and develop more informative diagnostic tools, we sequenced the genome of the novel phage associated with the RLO responsible for WS. Metagenomic sequencing libraries were prepared with extracted genomic DNA from two experimentally infected H. cracherodii and phage sequences were enriched using hydroxyapatite chromatography normalization. Normalized libraries were individually barcoded and sequenced with Illumina MiSeq. Raw sequence reads were processed using VIrominer and de novo assembly produced one single phage-like contig (35.7Kb) from the experimentally infected abalone. This highly divergent genome had closest homology with a virus associated with abalone shriveling syndrome (SS). Of the 34 predicted ORFs, overlapping homology with the SS virus ranged from 20-72%, demonstrating the phage sequenced is genetically distinct from any known phage. The phage-like sequences represented a significant portion of the total reads sequenced ( 2 million of the 12 million paired-end reads; 17%) and we obtained 94,000X coverage across the novel phage genome. Beyond characterization of this novel phage, which appears to reduce pathogenicity of the RLO, the genome enabled us to develop quantitative PCR and in situ hybridization assays as diagnostic tools. These tools allow us to detect and quantify this phage in the endangered H. cracherodii.

Synergistic Interaction Between Phage Therapy and Antibiotics Clears Pseudomonas Aeruginosa Infection in Endocarditis and Reduces Virulence.

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Oechslin, Frank; Piccardi, Philippe; Mancini, Stefano; Gabard, Jérôme; Moreillon, Philippe; Entenza, José M; Resch, Gregory; Que, Yok-Ai

2017-03-01

Increasing antibiotic resistance warrants therapeutic alternatives. Here we investigated the efficacy of bacteriophage-therapy (phage) alone or combined with antibiotics against experimental endocarditis (EE) due to Pseudomonas aeruginosa, an archetype of difficult-to-treat infection. In vitro fibrin clots and rats with aortic EE were treated with an antipseudomonas phage cocktail alone or combined with ciprofloxacin. Phage pharmacology, therapeutic efficacy, and resistance were determined. In vitro, single-dose phage therapy killed 7 log colony-forming units (CFUs)/g of fibrin clots in 6 hours. Phage-resistant mutants regrew after 24 hours but were prevented by combination with ciprofloxacin (2.5 × minimum inhibitory concentration). In vivo, single-dose phage therapy killed 2.5 log CFUs/g of vegetations in 6 hours (P 6 log CFUs/g of vegetations in 6 hours and successfully treating 64% (n = 7/11) of rats. Phage-resistant mutants emerged in vitro but not in vivo, most likely because resistant mutations affected bacterial surface determinants important for infectivity (eg, the pilT and galU genes involved in pilus motility and LPS formation). Single-dose phage therapy was active against P. aeruginosa EE and highly synergistic with ciprofloxacin. Phage-resistant mutants had impaired infectivity. Phage-therapy alone or combined with antibiotics merits further clinical consideration. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

Histopathological and molecular study of Neospora caninum infection in bovine aborted fetuses

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Amir Kamali

2014-12-01

Conclusions: The results showed N. caninum infection was detected in high percentage of aborted fetuses. In addition, at least one fourth of abortions caused by Neospora infection. These results indicate increasing number of abortions associated with the protozoa more than reported before in Iran.

Inhaled phage therapy: a promising and challenging approach to treat bacterial respiratory infections.

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Bodier-Montagutelli, Elsa; Morello, Eric; L'Hostis, Guillaume; Guillon, Antoine; Dalloneau, Emilie; Respaud, Renaud; Pallaoro, Nikita; Blois, Hélène; Vecellio, Laurent; Gabard, Jérôme; Heuzé-Vourc'h, Nathalie

2017-08-01

Bacterial respiratory tract infections (RTIs) are increasingly difficult to treat due to evolving antibiotic resistance. In this context, bacteriophages (or phages) are part of the foreseen alternatives or combination therapies. Delivering phages through the airways seems more relevant to accumulate these natural antibacterial viruses in proximity to their bacterial host, within the infectious site. Areas covered: This review addresses the potential of phage therapy to treat RTIs and discusses preclinical and clinical results of phages administration in this context. Recent phage formulation and aerosolization attempts are also reviewed, raising technical challenges to achieve efficient pulmonary deposition via inhalation. Expert opinion: Overall, the inhalation of phages as antibacterial treatment seems both clinically relevant and technically feasible. Several crucial points still need to be investigated, such as phage product pharmacokinetics and immunogenicity. Furthermore, given phage-specific features, appropriate regulatory and manufacturing guidelines will need to be defined. Finally, randomized controlled clinical trials should be carried out to establish phage therapy's clinical positioning in the antimicrobial arsenal against RTIs.

Histopathological and molecular study of Neospora caninum infection in bovine aborted fetuses

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Amir Kamali; HesamAdin Seifi; Ahmad Reza Movassaghi; Gholam Reza Razmi; Zahra Naseri

2014-01-01

To estimate the extent to which abortion in dairy cows was associated with of Neospora caninum (N. caninum) and to determine the risk factors of neosporosis in dairy farms from 9 provinces in Iran. Methods: Polymerase chain reaction (PCR) test was used to detect Neospora infection in the brain of 395 bovine aborted fetuses from 9 provinces of Iran. In addition, the brains of aborted fetuses were taken for histopathological examination. To identify the risk factors associated with neosporosis, data analysis was performed by SAS. Results: N. caninum was detected in 179 (45%) out of 395 fetal brain samples of bovine aborted fetuses using PCR. Among the PCR-positive brain samples, only 56 samples were suited for histopathological examination. The characteristic lesions of Neospora infection including non-suppurative encephalitis were found in 16 (28%) of PCR-positive samples. The risk factors including season, parity of dam, history of bovine virus diarrhea and infectious bovine rhinotracheitis infection in herd, cow’s milk production, herd size and fetal appearance did not show association with the infection. This study showed that Neospora caused abortion was significantly more in the second trimester of pregnancy than other periods. In addition, a significant association was observed between Neospora infection and stillbirth. Conclusions: The results showed N. caninum infection was detected in high percentage of aborted fetuses. In addition, at least one fourth of abortions caused by Neospora infection. These results indicate increasing number of abortions associated with the protozoa more than reported before in Iran.

Histopathological and molecular study of Neospora caninum infection in bovine aborted fetuses

Institute of Scientific and Technical Information of China (English)

Amir; Kamali; Hesam; Adin; Seifi; Ahmad; Reza; Movassaghi; Gholam; Reza; Razmi; Zahra; Naseri

2014-01-01

Objective:To estimate the extent to which abortion in dairy cows was associated with of Neospom caninum(N.caninum) and to determine the risk factors of neosporosis in dairy farms from 9 provinces in Iran.Methods:Polymerase chain reaction(PCR) test was used to detect Neospora infection in the brain of 395 bovine aborted fetuses from 9 provinces of Iran.In addition,the brains of aborted fetuses were taken for histopathological examination.To identify the risk factors associated with neosporosis,data analysis was performed by SAS.Results:N.caninum was detected in 179(45%) out of 395 fetal brain samples of bovine aborted fetuses using PCR.Among the PCR-positive brain samples,only 56 samples were suited for histopathological examination.The characteristic lesions of Neospora infection including non-suppurative encephalitis were found in 16(28%) of PCR-positive samples.The risk factors including season,parity of dam,history of bovine virus diarrhea and infectious bovine rhinotracheitis infection in herd,cow’s milk production,herd size and fetal appearance did not show association with the infection.This study showed that Neospora caused abortion was significantly more in the second trimester of pregnancy than other periods.In addition,a significant association was observed between Neospora infection and stillbirth.Conclusions:The results showed N.caninum infection was detected in high percentage of aborted fetuses.In addition,at least one fourth of abortions caused by Neospora infection.These results indicate increasing number of abortions associated with the protozoa more than reported before in Iran.

Strain Specific Phage Treatment for Staphylococcus aureus Infection Is Influenced by Host Immunity and Site of Infection.

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Nathan B Pincus

Full Text Available The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a "post-antibiotic era", the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA, in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use.

Strain Specific Phage Treatment for Staphylococcus aureus Infection Is Influenced by Host Immunity and Site of Infection.

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Pincus, Nathan B; Reckhow, Jensen D; Saleem, Danial; Jammeh, Momodou L; Datta, Sandip K; Myles, Ian A

2015-01-01

The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a "post-antibiotic era", the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA), in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use.

Impact of reducing and oxidizing agents on the infectivity of Qβ phage and the overall structure of its capsid.

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Loison, Pauline; Majou, Didier; Gelhaye, Eric; Boudaud, Nicolas; Gantzer, Christophe

2016-11-01

Qβ phages infect Escherichia coli in the human gut by recognizing F-pili as receptors. Infection therefore occurs under reducing conditions induced by physiological agents (e.g. glutathione) or the intestinal bacterial flora. After excretion in the environment, phage particles are exposed to oxidizing conditions and sometimes disinfection. If inactivation does not occur, the phage may infect new hosts in the human gut through the oral route. During such a life cycle, we demonstrated that, outside the human gut, cysteines of the major protein capsid of Qβ phage form disulfide bonds. Disinfection with NaClO does not allow overoxidation to occur. Such oxidation induces inactivation rather by irreversible damage to the minor proteins. In the presence of glutathione, most disulfide bonds are reduced, which slightly increases the capacity of the phage to infect E. coli in vitro Such reduction is reversible and barely alters infectivity of the phage. Reduction of all disulfide bonds by dithiothreitol leads to complete capsid destabilization. These data provide new insights into how the phages are impacted by oxidizing-reducing conditions outside their host cell and raises the possibility of the intervention of the redox during life cycle of the phage. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Biological control of Aeromonas salmonicida subsp. salmonicida infection in rainbow trout (Oncorhynchus mykiss) using Aeromonas phage PAS-1.

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Kim, J H; Choresca, C H; Shin, S P; Han, J E; Jun, J W; Park, S C

2015-02-01

The potential control efficacy of Aeromonas phage PAS-1 was evaluated against Aeromonas salmonicida subsp. salmonicida infection in rainbow trout (Oncorhynchus mykiss) model in this study. The phage was co-cultured with the virulent A. salmonicida subsp. salmonicida strain AS05 that possesses the type III secretion system (TTSS) ascV gene, and efficient bacteriolytic activity was observed against the bacteria. The administration of PAS-1 in rainbow trout demonstrated that the phage was cleared from the fish within 200 h post-administration, and a temporal neutralizing activity against the phage was detected in the sera of phage-administrated fish. The administration of PAS-1 (multiplicity of infection: 10 000) in A. salmonicida subsp. salmonicida infected rainbow trout model showed notable protective effects, with increased survival rates and mean times to death. These results demonstrated that Aeromonas phage PAS-1 could be considered as an alternative biological control agent against A. salmonicida subsp. salmonicida infections in rainbow trout culture. © 2013 Blackwell Verlag GmbH.

Novel phage group infecting Lactobacillus delbrueckii subsp. lactis, as revealed by genomic and proteomic analysis of bacteriophage Ldl1.

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Casey, Eoghan; Mahony, Jennifer; Neve, Horst; Noben, Jean-Paul; Dal Bello, Fabio; van Sinderen, Douwe

2015-02-01

Ldl1 is a virulent phage infecting the dairy starter Lactobacillus delbrueckii subsp. lactis LdlS. Electron microscopy analysis revealed that this phage exhibits a large head and a long tail and bears little resemblance to other characterized phages infecting Lactobacillus delbrueckii. In vitro propagation of this phage revealed a latent period of 30 to 40 min and a burst size of 59.9 +/- 1.9 phage particles. Comparative genomic and proteomic analyses showed remarkable similarity between the genome of Ldl1 and that of Lactobacillus plantarum phage ATCC 8014-B2. The genomic and proteomic characteristics of Ldl1 demonstrate that this phage does not belong to any of the four previously recognized L. delbrueckii phage groups, necessitating the creation of a new group, called group e, thus adding to the knowledge on the diversity of phages targeting strains of this industrially important lactic acid bacterial species.

Transcription Profiling of Bacillus subtilis Cells Infected with AR9, a Giant Phage Encoding Two Multisubunit RNA Polymerases.

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Lavysh, Daria; Sokolova, Maria; Slashcheva, Marina; Förstner, Konrad U; Severinov, Konstantin

2017-02-14

Bacteriophage AR9 is a recently sequenced jumbo phage that encodes two multisubunit RNA polymerases. Here we investigated the AR9 transcription strategy and the effect of AR9 infection on the transcription of its host, Bacillus subtilis Analysis of whole-genome transcription revealed early, late, and continuously expressed AR9 genes. Alignment of sequences upstream of the 5' ends of AR9 transcripts revealed consensus sequences that define early and late phage promoters. Continuously expressed AR9 genes have both early and late promoters in front of them. Early AR9 transcription is independent of protein synthesis and must be determined by virion RNA polymerase injected together with viral DNA. During infection, the overall amount of host mRNAs is significantly decreased. Analysis of relative amounts of host transcripts revealed notable differences in the levels of some mRNAs. The physiological significance of up- or downregulation of host genes for AR9 phage infection remains to be established. AR9 infection is significantly affected by rifampin, an inhibitor of host RNA polymerase transcription. The effect is likely caused by the antibiotic-induced killing of host cells, while phage genome transcription is solely performed by viral RNA polymerases. IMPORTANCE Phages regulate the timing of the expression of their own genes to coordinate processes in the infected cell and maximize the release of viral progeny. Phages also alter the levels of host transcripts. Here we present the results of a temporal analysis of the host and viral transcriptomes of Bacillus subtilis infected with a giant phage, AR9. We identify viral promoters recognized by two virus-encoded RNA polymerases that are a unique feature of the phiKZ-related group of phages to which AR9 belongs. Our results set the stage for future analyses of highly unusual RNA polymerases encoded by AR9 and other phiKZ-related phages. Copyright © 2017 Lavysh et al.

Development of anti-infectives using phage display: biological agents against bacteria, viruses, and parasites.

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Huang, Johnny X; Bishop-Hurley, Sharon L; Cooper, Matthew A

2012-09-01

The vast majority of anti-infective therapeutics on the market or in development are small molecules; however, there is now a nascent pipeline of biological agents in development. Until recently, phage display technologies were used mainly to produce monoclonal antibodies (MAbs) targeted against cancer or inflammatory disease targets. Patent disputes impeded broad use of these methods and contributed to the dearth of candidates in the clinic during the 1990s. Today, however, phage display is recognized as a powerful tool for selecting novel peptides and antibodies that can bind to a wide range of antigens, ranging from whole cells to proteins and lipid targets. In this review, we highlight research that exploits phage display technology as a means of discovering novel therapeutics against infectious diseases, with a focus on antimicrobial peptides and antibodies in clinical or preclinical development. We discuss the different strategies and methods used to derive, select, and develop anti-infectives from phage display libraries and then highlight case studies of drug candidates in the process of development and commercialization. Advances in screening, manufacturing, and humanization technologies now mean that phage display can make a significant contribution in the fight against clinically important pathogens.

A Genetic Approach to the Development of New Therapeutic Phages to Fight Pseudomonas Aeruginosa in Wound Infections

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Elena Pleteneva

2012-12-01

Full Text Available Pseudomonas aeruginosa is a frequent participant in wound infections. Emergence of multiple antibiotic resistant strains has created significant problems in the treatment of infected wounds. Phage therapy (PT has been proposed as a possible alternative approach. Infected wounds are the perfect place for PT applications, since the basic condition for PT is ensured; namely, the direct contact of bacteria and their viruses. Plenty of virulent (“lytic” and temperate (“lysogenic” bacteriophages are known in P. aeruginosa. However, the number of virulent phage species acceptable for PT and their mutability are limited. Besides, there are different deviations in the behavior of virulent (and temperate phages from their expected canonical models of development. We consider some examples of non-canonical phage-bacterium interactions and the possibility of their use in PT. In addition, some optimal approaches to the development of phage therapy will be discussed from the point of view of a biologist, considering the danger of phage-assisted horizontal gene transfer (HGT, and from the point of view of a surgeon who has accepted the Hippocrates Oath to cure patients by all possible means. It is also time now to discuss the possible approaches in international cooperation for the development of PT. We think it would be advantageous to make phage therapy a kind of personalized medicine.

Three New Escherichia coli Phages from the Human Gut Show Promising Potential for Phage Therapy.

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Marion Dalmasso

Full Text Available With the emergence of multi-drug resistant bacteria the use of bacteriophages (phages is gaining renewed interest as promising anti-microbial agents. The aim of this study was to isolate and characterize phages from human fecal samples. Three new coliphages, ɸAPCEc01, ɸAPCEc02 and ɸAPCEc03, were isolated. Their phenotypic and genomic characteristics, and lytic activity against biofilm, and in combination with ciprofloxacin, were investigated. All three phages reduced the growth of E. coli strain DPC6051 at multiplicity of infection (MOI between 10-3 and 105. A cocktail of all three phages completely inhibited the growth of E. coli. The phage cocktail also reduced biofilm formation and prevented the emergence of phage-resistant mutants which occurred with single phage. When combined with ciprofloxacin, phage alone or in cocktail inhibited the growth of E. coli and prevented the emergence of resistant mutants. These three new phages are promising biocontrol agents for E. coli infections.

The extracellular phage-host interactions involved in the bacteriophage LL-H infection of Lactobacillus delbrueckii ssp. lactis ATCC 15808.

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Munsch-Alatossava, Patricia; Alatossava, Tapani

2013-12-24

The complete genome sequence of Lactobacillus bacteriophage LL-H was determined in 1996. Accordingly, LL-H has been used as a model phage for the infection of dairy Lactobacillus, specifically for thermophilic Lactobacillus delbrueckii ssp. lactis host strains, such as ATCC 15808. One of the major goals of phage LL-H research consisted of the characterization of the first phage-host interactions at the level of phage adsorption and phage DNA injection steps to determine effective and practical methods to minimize the risks associated with the appearance and attack of phages in the manufacture of yogurt, and Swiss or Italian hard type cheeses, which typically use thermophilic lactic acid bacteria starter cultures containing L. delbrueckii strains among others. This mini review article summarizes the present data concerning (i) the special features, particle structure, and components of phage LL-H and (ii) the structure and properties of lipoteichoic acids (LTAs), which are the phage LL-H receptor components of L. delbrueckii ssp. lactis host strains. Moreover, a model of the first, extracellular, phage-host interactions for the infection of L. delbrueckii ssp. lactis ATCC 15808 by phage LL-H is presented and further discussed.

The extracellular phage-host interactions involved in the bacteriophage LL-H infection of Lactobacillus delbrueckii ssp. lactis ATCC 15808

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Patricia eMunsch-Alatossava

2013-12-01

Full Text Available The complete genome sequence of Lactobacillus bacteriophage LL-H was determined in 1996. Accordingly, LL-H has been used as a model phage for the infection of dairy Lactobacillus, specifically for thermophilic Lb. delbrueckii ssp. lactis host strains, such as ATCC 15808. One of the major goals of phage LL-H research consisted of the characterization of the the first phage-host interactions at the level of phage adsorption and phage DNA injection steps to determine effective and practical methods to minimise the risks associated with the appearance and attack of phages in the manufacture of yoghurt, and Swiss or Italian type hard cheeses, which typically use thermophilic LAB starter cultures containing Lb. delbrueckii strains among others. This mini review article summarises the present data concerning (i the special features, particle structure and components of phage LL-H and (ii the structure and properties of lipoteichoic acids (LTAs, which are the phage LL-H receptor components of Lb. delbrueckii ssp. lactis host strains. Moreover, a model of the first, extracellular, phage-host interactions for the infection of Lb. delbrueckii ssp. lactis ATCC 15808 by phage LL-H is presented and further discussed.

Expert Opinion on Three Phage Therapy Related Topics: Bacterial Phage Resistance, Phage Training and Prophages in Bacterial Production Strains

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Christine Rohde

2018-04-01

Full Text Available Phage therapy is increasingly put forward as a “new” potential tool in the fight against antibiotic resistant infections. During the “Centennial Celebration of Bacteriophage Research” conference in Tbilisi, Georgia on 26–29 June 2017, an international group of phage researchers committed to elaborate an expert opinion on three contentious phage therapy related issues that are hampering clinical progress in the field of phage therapy. This paper explores and discusses bacterial phage resistance, phage training and the presence of prophages in bacterial production strains while reviewing relevant research findings and experiences. Our purpose is to inform phage therapy stakeholders such as policy makers, officials of the competent authorities for medicines, phage researchers and phage producers, and members of the pharmaceutical industry. This brief also points out potential avenues for future phage therapy research and development as it specifically addresses those overarching questions that currently call for attention whenever phages go into purification processes for application.

Phage-Host Interactions in Flavobacterium psychrophilum and the Potential for Phage Therapy in Aquaculture

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Christiansen, Rói Hammershaimb

, the increasing problem with antibiotic resistance has led to increased attention to the use of phages for controlling F. psychrophilum infections in aquaculture. In a synopsis and four scientific papers, this PhD project studies the potential and optimizes the use of phage therapy for treatment and prevention......, studies of the genetic diversity and susceptibility patterns of F. psychrophilum strains and phages isolated in three geographically distinct areas (Chile, Denmark, and USA) showed that the strains and phages clustered into geographically distinct groups. However, cross-infectivity between Chilean phage......-phage. In the third paper, a detailed analysis of the resistance mechanisms in F. psychrophilum and six phage resistant mutants was done. The results revealed unique changes in the genomes in all the phage resistant strains and that some of these changes were related to cell surface properties which were suggested...

Synergy as a rationale for phage therapy using phage cocktails.

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Schmerer, Matthew; Molineux, Ian J; Bull, James J

2014-01-01

Where phages are used to treat bacterial contaminations and infections, multiple phages are typically applied at once as a cocktail. When two or more phages in the cocktail attack the same bacterium, the combination may produce better killing than any single phage (synergy) or the combination may be worse than the best single phage (interference). Synergy is of obvious utility, especially if it can be predicted a priori, but it remains poorly documented with few examples known. This study addresses synergy in which one phage improves adsorption by a second phage. It first presents evidence of synergy from an experimental system of two phages and a mucoid E. coli host. The synergy likely stems from a tailspike enzyme produced by one of the phages. We then offer mathematical models and simulations to understand the dynamics of synergy and the enhanced magnitude of bacterial control possible. The models and observations complement each other and suggest that synergy may be of widespread utility and may be predictable from easily observed phenotypes.

Phage Therapy: Eco-Physiological Pharmacology

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Stephen T. Abedon

2014-01-01

Full Text Available Bacterial virus use as antibacterial agents, in the guise of what is commonly known as phage therapy, is an inherently physiological, ecological, and also pharmacological process. Physiologically we can consider metabolic properties of phage infections of bacteria and variation in those properties as a function of preexisting bacterial states. In addition, there are patient responses to pathogenesis, patient responses to phage infections of pathogens, and also patient responses to phage virions alone. Ecologically, we can consider phage propagation, densities, distribution (within bodies, impact on body-associated microbiota (as ecological communities, and modification of the functioning of body “ecosystems” more generally. These ecological and physiological components in many ways represent different perspectives on otherwise equivalent phenomena. Comparable to drugs, one also can view phages during phage therapy in pharmacological terms. The relatively unique status of phages within the context of phage therapy as essentially replicating antimicrobials can therefore result in a confluence of perspectives, many of which can be useful towards gaining a better mechanistic appreciation of phage therapy, as I consider here. Pharmacology more generally may be viewed as a discipline that lies at an interface between organism-associated phenomena, as considered by physiology, and environmental interactions as considered by ecology.

Acinetobacter phage genome is similar to Sphinx 2.36, the circular DNA copurified with TSE infected particles.

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Longkumer, Toshisangba; Kamireddy, Swetha; Muthyala, Venkateswar Reddy; Akbarpasha, Shaikh; Pitchika, Gopi Krishna; Kodetham, Gopinath; Ayaluru, Murali; Siddavattam, Dayananda

2013-01-01

While analyzing plasmids of Acinetobacter sp. DS002 we have detected a circular DNA molecule pTS236, which upon further investigation is identified as the genome of a phage. The phage genome has shown sequence similarity to the recently discovered Sphinx 2.36 DNA sequence co-purified with the Transmissible Spongiform Encephalopathy (TSE) particles isolated from infected brain samples collected from diverse geographical regions. As in Sphinx 2.36, the phage genome also codes for three proteins. One of them codes for RepA and is shown to be involved in replication of pTS236 through rolling circle (RC) mode. The other two translationally coupled ORFs, orf106 and orf96, code for coat proteins of the phage. Although an orf96 homologue was not previously reported in Sphinx 2.36, a closer examination of DNA sequence of Sphinx 2.36 revealed its presence downstream of orf106 homologue. TEM images and infection assays revealed existence of phage AbDs1 in Acinetobacter sp. DS002.

Formulation, stabilisation and encapsulation of bacteriophage for phage therapy.

Science.gov (United States)

Malik, Danish J; Sokolov, Ilya J; Vinner, Gurinder K; Mancuso, Francesco; Cinquerrui, Salvatore; Vladisavljevic, Goran T; Clokie, Martha R J; Garton, Natalie J; Stapley, Andrew G F; Kirpichnikova, Anna

2017-11-01

Against a backdrop of global antibiotic resistance and increasing awareness of the importance of the human microbiota, there has been resurgent interest in the potential use of bacteriophages for therapeutic purposes, known as phage therapy. A number of phage therapy phase I and II clinical trials have concluded, and shown phages don't present significant adverse safety concerns. These clinical trials used simple phage suspensions without any formulation and phage stability was of secondary concern. Phages have a limited stability in solution, and undergo a significant drop in phage titre during processing and storage which is unacceptable if phages are to become regulated pharmaceuticals, where stable dosage and well defined pharmacokinetics and pharmacodynamics are de rigueur. Animal studies have shown that the efficacy of phage therapy outcomes depend on the phage concentration (i.e. the dose) delivered at the site of infection, and their ability to target and kill bacteria, arresting bacterial growth and clearing the infection. In addition, in vitro and animal studies have shown the importance of using phage cocktails rather than single phage preparations to achieve better therapy outcomes. The in vivo reduction of phage concentration due to interactions with host antibodies or other clearance mechanisms may necessitate repeated dosing of phages, or sustained release approaches. Modelling of phage-bacterium population dynamics reinforces these points. Surprisingly little attention has been devoted to the effect of formulation on phage therapy outcomes, given the need for phage cocktails, where each phage within a cocktail may require significantly different formulation to retain a high enough infective dose. This review firstly looks at the clinical needs and challenges (informed through a review of key animal studies evaluating phage therapy) associated with treatment of acute and chronic infections and the drivers for phage encapsulation. An important driver

Development of a Phage Cocktail to Control Proteus mirabilis Catheter-associated Urinary Tract Infections

Science.gov (United States)

Melo, Luís D. R.; Veiga, Patrícia; Cerca, Nuno; Kropinski, Andrew M.; Almeida, Carina; Azeredo, Joana; Sillankorva, Sanna

2016-01-01

Proteus mirabilis is an enterobacterium that causes catheter-associated urinary tract infections (CAUTIs) due to its ability to colonize and form crystalline biofilms on the catheters surface. CAUTIs are very difficult to treat, since biofilm structures are highly tolerant to antibiotics. Phages have been used widely to control a diversity of bacterial species, however, a limited number of phages for P. mirabilis have been isolated and studied. Here we report the isolation of two novel virulent phages, the podovirus vB_PmiP_5460 and the myovirus vB_PmiM_5461, which are able to target, respectively, 16 of the 26 and all the Proteus strains tested in this study. Both phages have been characterized thoroughly and sequencing data revealed no traces of genes associated with lysogeny. To further evaluate the phages’ ability to prevent catheter’s colonization by Proteus, the phages adherence to silicone surfaces was assessed. Further tests in phage-coated catheters using a dynamic biofilm model simulating CAUTIs, have shown a significant reduction of P. mirabilis biofilm formation up to 168 h of catheterization. These results highlight the potential usefulness of the two isolated phages for the prevention of surface colonization by this bacterium. PMID:27446059

Reproductive tract infections in women seeking abortion in Vietnam

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Thủy Đỗ

2009-01-01

Full Text Available Abstract Background Women requesting abortion are at increased risk of developing RTI complications. However, RTI control in many resource-poor countries including Vietnam have been faced with logistical and methodological problems due to lack of standardized definitions of RTIs, lack of well-validated diagnostic criteria, lack of accurate laboratory tests, and lack of diagnostic equipment and skills. This article investigates the prevalence of RTIs among Vietnamese abortion-seeking women, to evaluate the available diagnostic techniques, and to assess antibiotic resistance among aetiological agents of RTI. Method The study was conducted in Phu-San hospital (PSH from December 2003 through April 2004 among 748 abortion clients. A structured questionnaire was used to collect data on socio-economic and reproductive characteristics. Specimens were collected for laboratory analyses of chlamydia, gonorrhoea, trichomoniasis, vaginal candidiasis (VC, bacterial vaginosis (BV and syphilis. To assess the validity of the obtained results, the study was repeated among 100 women and the duplicate samples were analysed at PSH and Copenhagen University Hospital (CUH. Results In all 54% of the women were diagnosed as having an RTI, including 3.3% with sexually transmitted infections. Endogenous infections were most prevalent (VC 34% and BV 12% followed by chlamydia (1.3% and trichomoniasis (0.7%. The sensitivity of culture for VC and BV was 30% and 88%, respectively, when tests in PSH were measured against tests in CUH. Antibiotic resistance was common among bacterial isolates. Conclusion RTIs are common among women seeking abortion. The presence of RTIs is associated with an increased risk of developing iatrogenic infections, routine administration of prophylactic antibiotic to all women undergoing abortion should be considered. However, the choice of routine prophylactic antibiotics should be based on relevant surveillance data of antibiotic resistance

Characterization of Two Virulent Phages of Lactobacillus plantarum

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Briggiler Marcó, Mariángeles; Garneau, Josiane E.; Tremblay, Denise; Quiberoni, Andrea

2012-01-01

We characterized two Lactobacillus plantarum virulent siphophages, ATCC 8014-B1 (B1) and ATCC 8014-B2 (B2), previously isolated from corn silage and anaerobic sewage sludge, respectively. Phage B2 infected two of the eight L. plantarum strains tested, while phage B1 infected three. Phage adsorption was highly variable depending on the strain used. Phage defense systems were found in at least two L. plantarum strains, LMG9211 and WCSF1. The linear double-stranded DNA genome of the pac-type phage B1 had 38,002 bp, a G+C content of 47.6%, and 60 open reading frames (ORFs). Surprisingly, the phage B1 genome has 97% identity with that of Pediococcus damnosus phage clP1 and 77% identity with that of L. plantarum phage JL-1; these phages were isolated from sewage and cucumber fermentation, respectively. The double-stranded DNA (dsDNA) genome of the cos-type phage B2 had 80,618 bp, a G+C content of 36.9%, and 127 ORFs with similarities to those of Bacillus and Lactobacillus strains as well as phages. Some phage B2 genes were similar to ORFs from L. plantarum phage LP65 of the Myoviridae family. Additionally, 6 tRNAs were found in the phage B2 genome. Protein analysis revealed 13 (phage B1) and 9 (phage B2) structural proteins. To our knowledge, this is the first report describing such high identity between phage genomes infecting different genera of lactic acid bacteria. PMID:23042172

Intranasal infection with Chlamydia abortus induces dose-dependent latency and abortion in sheep.

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David Longbottom

Full Text Available Latency is a key feature of the animal pathogen Chlamydia abortus, where infection remains inapparent in the non-pregnant animal and only becomes evident during a subsequent pregnancy. Often the first sign that an animal is infected is abortion occurring late in gestation. Despite this, little is understood of the underlying mechanisms that control latency or the recrudescence of infection that occurs during subsequent pregnancy. The aim of this study was to develop an experimental model of latency by mimicking the natural route of infection through the intranasal inoculation of non-pregnant sheep with C. abortus.Three groups of sheep (groups 1, 2 and 3 were experimentally infected with different doses of C. abortus (5×10(3, 5×10(5 and 5×10(7 inclusion forming units (IFU, respectively prior to mating and monitored over 2 breeding cycles for clinical, microbiological, pathological, immunological and serological outcomes. Two further groups received either negative control inoculum (group 4a,b or were inoculated subcutaneously on day 70 of gestation with 2×10(6 IFU C. abortus (group 5. Animals in groups 1, 2 and 5 experienced an abortion rate of 50-67%, while only one animal aborted in group 3 and none in group 4a,b. Pathological, microbiological, immunological and serological analyses support the view that the maternal protective immune response is influenced by initial exposure to the bacterium.The results show that intranasal administration of non-pregnant sheep with a low/medium dose of C. abortus results in a latent infection that leads in a subsequent pregnancy to infection of the placenta and abortion. In contrast a high dose stimulates protective immunity, resulting in a much lower abortion rate. This model will be useful in understanding the mechanisms of infection underlying latency and onset of disease, as well as in the development of novel therapeutics and vaccines for controlling infection.

Intranasal infection with Chlamydia abortus induces dose-dependent latency and abortion in sheep.

Science.gov (United States)

Longbottom, David; Livingstone, Morag; Maley, Stephen; van der Zon, Arjan; Rocchi, Mara; Wilson, Kim; Wheelhouse, Nicholas; Dagleish, Mark; Aitchison, Kevin; Wattegedera, Sean; Nath, Mintu; Entrican, Gary; Buxton, David

2013-01-01

Latency is a key feature of the animal pathogen Chlamydia abortus, where infection remains inapparent in the non-pregnant animal and only becomes evident during a subsequent pregnancy. Often the first sign that an animal is infected is abortion occurring late in gestation. Despite this, little is understood of the underlying mechanisms that control latency or the recrudescence of infection that occurs during subsequent pregnancy. The aim of this study was to develop an experimental model of latency by mimicking the natural route of infection through the intranasal inoculation of non-pregnant sheep with C. abortus. Three groups of sheep (groups 1, 2 and 3) were experimentally infected with different doses of C. abortus (5×10(3), 5×10(5) and 5×10(7) inclusion forming units (IFU), respectively) prior to mating and monitored over 2 breeding cycles for clinical, microbiological, pathological, immunological and serological outcomes. Two further groups received either negative control inoculum (group 4a,b) or were inoculated subcutaneously on day 70 of gestation with 2×10(6) IFU C. abortus (group 5). Animals in groups 1, 2 and 5 experienced an abortion rate of 50-67%, while only one animal aborted in group 3 and none in group 4a,b. Pathological, microbiological, immunological and serological analyses support the view that the maternal protective immune response is influenced by initial exposure to the bacterium. The results show that intranasal administration of non-pregnant sheep with a low/medium dose of C. abortus results in a latent infection that leads in a subsequent pregnancy to infection of the placenta and abortion. In contrast a high dose stimulates protective immunity, resulting in a much lower abortion rate. This model will be useful in understanding the mechanisms of infection underlying latency and onset of disease, as well as in the development of novel therapeutics and vaccines for controlling infection.

Phage inactivation by triplet acetone

International Nuclear Information System (INIS)

Gomes, R.A.

1985-01-01

The exposure of lambda phage to triplet acetone is studied. The triplet acetone is obtained from aerobic oxidation of isobutanal catalysed by peroxidase. A decrease of lambda phage ability to infect Escherichia coli is reported, perhaps, partially due to the possible production of lesions in the phage genome. (M.A.C.) [pt

Phase variable expression of a single phage receptor in Campylobacter jejuni NCTC12662 influences sensitivity toward several diverse CPS-dependent phages

DEFF Research Database (Denmark)

Gencay, Yilmaz Emre; Sørensen, Martine C.H.; Wenzel, Cory Q.

2018-01-01

Campylobacter jejuni NCTC12662 is sensitive to infection by many Campylobacter bacteriophages. Here we used this strain to investigate the molecular mechanism behind phage resistance development when exposed to a single phage and demonstrate how phase variable expression of one surface component...... influences phage sensitivity against many diverse C. jejuni phages. When C. jejuni NCTC12662 was exposed to phage F207 overnight, 25% of the bacterial cells were able to grow on a lawn of phage F207, suggesting that resistance develops at a high frequency. One resistant variant, 12662R, was further...... characterized and shown to be an adsorption mutant. Plaque assays using our large phage collection showed that seven out of 36 diverse capsular polysaccharide (CPS)-dependent phages could not infect 12662R, whereas the remaining phages formed plaques on 12662R with reduced efficiencies. Analysis of the CPS...

Use of phages to control Vibrio splendidus infection in the juvenile sea cucumber Apostichopus japonicus.

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Li, Zhen; Li, Xiaoyu; Zhang, Jiancheng; Wang, Xitao; Wang, Lili; Cao, Zhenhui; Xu, Yongping

2016-07-01

of the sea cucumbers. The control was injected with 1 ml of sterilized seawater while the untreated group and the test group were injected with the same volume of V. splendidus-ABTNL culture (3 × 10(5) CFU/mL). Then, the test group was injected with 1 ml of the 3 phage cocktail (MOI = 10). After 48 h, the activities of lysozyme, acid phosphatase and superoxide dismutase were elevated in the untreated group while the levels of these enzymes in the test group were similar to the blank control. After 10-day observation, the survival rate of the sea cucumber was 100% for the blank control, 80% for the test group and 20% for the negative control. The overall results of this experiment indicate that phage therapy increased the survival of sea cucumber infected with V. splendidus VS-ABTNL. The above results demonstrate that using phages, especially a combination of different phages, may be a feasible way to control Vibrio infection in the sea cucumber industry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Isolation and characterization of ZZ1, a novel lytic phage that infects Acinetobacter baumannii clinical isolates

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Jin Jing

2012-07-01

Full Text Available Abstract Background Acinetobacter baumannii, a significant nosocomial pathogen, has evolved resistance to almost all conventional antimicrobial drugs. Bacteriophage therapy is a potential alternative treatment for multidrug-resistant bacterial infections. In this study, one lytic bacteriophage, ZZ1, which infects A. baumannii and has a broad host range, was selected for characterization. Results Phage ZZ1 and 3 of its natural hosts, A. baumanni clinical isolates AB09V, AB0902, and AB0901, are described in this study. The 3 strains have different sensitivities to ZZ1, but they have the same sensitivity to antibiotics. They are resistant to almost all of the antibiotics tested, except for polymyxin. Several aspects of the life cycle of ZZ1 were investigated using the sensitive strain AB09V under optimal growth conditions. ZZ1 is highly infectious with a short latent period (9 min and a large burst size (200 PFU/cell. It exhibited the most powerful antibacterial activity at temperatures ranging from 35°C to 39°C. Moreover, when ZZ1 alone was incubated at different pHs and different temperatures, the phage was stable over a wide pH range (4 to 9 and at extreme temperatures (between 50°C and 60°C. ZZ1 possesses a 100-nm icosahedral head containing double-stranded DNA with a total length of 166,682 bp and a 120-nm long contractile tail. Morphologically, it could be classified as a member of the Myoviridae family and the Caudovirales order. Bioinformatic analysis of the phage whole genome sequence further suggested that ZZ1 was more likely to be a new member of the Myoviridae phages. Most of the predicted ORFs of the phage were similar to the predicted ORFs from other Acinetobacter phages. Conclusion The phage ZZ1 has a relatively broad lytic spectrum, high pH stability, strong heat resistance, and efficient antibacterial potential at body temperature. These characteristics greatly increase the utility of this phage as an antibacterial agent

Isolation and characterization of ZZ1, a novel lytic phage that infects Acinetobacter baumannii clinical isolates.

Science.gov (United States)

Jin, Jing; Li, Zhen-Jiang; Wang, Shu-Wei; Wang, Shan-Mei; Huang, De-Hai; Li, Ya-Hui; Ma, Yun-Yun; Wang, Jin; Liu, Fang; Chen, Xiang-Dong; Li, Guang-Xing; Wang, Xiao-Ting; Wang, Zhong-Quan; Zhao, Guo-Qiang

2012-07-28

Acinetobacter baumannii, a significant nosocomial pathogen, has evolved resistance to almost all conventional antimicrobial drugs. Bacteriophage therapy is a potential alternative treatment for multidrug-resistant bacterial infections. In this study, one lytic bacteriophage, ZZ1, which infects A. baumannii and has a broad host range, was selected for characterization. Phage ZZ1 and 3 of its natural hosts, A. baumanni clinical isolates AB09V, AB0902, and AB0901, are described in this study. The 3 strains have different sensitivities to ZZ1, but they have the same sensitivity to antibiotics. They are resistant to almost all of the antibiotics tested, except for polymyxin. Several aspects of the life cycle of ZZ1 were investigated using the sensitive strain AB09V under optimal growth conditions. ZZ1 is highly infectious with a short latent period (9 min) and a large burst size (200 PFU/cell). It exhibited the most powerful antibacterial activity at temperatures ranging from 35°C to 39°C. Moreover, when ZZ1 alone was incubated at different pHs and different temperatures, the phage was stable over a wide pH range (4 to 9) and at extreme temperatures (between 50°C and 60°C). ZZ1 possesses a 100-nm icosahedral head containing double-stranded DNA with a total length of 166,682 bp and a 120-nm long contractile tail. Morphologically, it could be classified as a member of the Myoviridae family and the Caudovirales order. Bioinformatic analysis of the phage whole genome sequence further suggested that ZZ1 was more likely to be a new member of the Myoviridae phages. Most of the predicted ORFs of the phage were similar to the predicted ORFs from other Acinetobacter phages. The phage ZZ1 has a relatively broad lytic spectrum, high pH stability, strong heat resistance, and efficient antibacterial potential at body temperature. These characteristics greatly increase the utility of this phage as an antibacterial agent; thus, it should be further investigated.

Protein Expression Modifications in Phage-Resistant Mutants of Aeromonas salmonicida after AS-A Phage Treatment

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Catarina Moreirinha

2018-03-01

Full Text Available The occurrence of infections by pathogenic bacteria is one of the main sources of financial loss for the aquaculture industry. This problem often cannot be solved with antibiotic treatment or vaccination. Phage therapy seems to be an alternative environmentally-friendly strategy to control infections. Recognizing the cellular modifications that bacteriophage therapy may cause to the host is essential in order to confirm microbial inactivation, while understanding the mechanisms that drive the development of phage-resistant strains. The aim of this work was to detect cellular modifications that occur after phage AS-A treatment in A. salmonicida, an important fish pathogen. Phage-resistant and susceptible cells were subjected to five successive streak-plating steps and analysed with infrared spectroscopy, a fast and powerful tool for cell study. The spectral differences of both populations were investigated and compared with a phage sensitivity profile, obtained through the spot test and efficiency of plating. Changes in protein associated peaks were found, and these results were corroborated by 1-D electrophoresis of intracellular proteins analysis and by phage sensitivity profiles. Phage AS-A treatment before the first streaking-plate step clearly affected the intracellular proteins expression levels of phage-resistant clones, altering the expression of distinct proteins during the subsequent five successive streak-plating steps, making these clones recover and be phenotypically more similar to the sensitive cells.

A leucine repeat motif in AbiA is required for resistance of Lactococcus lactis to phages representing three species.

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Dinsmore, P K; O'Sullivan, D J; Klaenhammer, T R

1998-05-28

The abiA gene encodes an abortive bacteriophage infection mechanism that can protect Lactococcus species from infection by a variety of bacteriophages including three unrelated phage species. Five heptad leucine repeats suggestive of a leucine zipper motif were identified between residues 232 and 266 in the predicted amino acid sequence of the AbiA protein. The biological role of residues in the repeats was investigated by incorporating amino acid substitutions via site-directed mutagenesis. Each mutant was tested for phage resistance against three phages, phi 31, sk1, and c2, belonging to species P335, 936, and c2, respectively. The five residues that comprise the heptad repeats were designated L234, L242, A249, L256, and L263. Three single conservative mutations of leucine to valine in positions L235, L242, and L263 and a double mutation of two leucines (L235 and L242) to valines did not affect AbiA activity on any phages tested. Non-conservative single substitutions of charged amino acids for three of the leucines (L235, L242, and L256) virtually eliminated AbiA activity on all phages tested. Substitution of the alanine residue in the third repeat (A249) with a charged residue did not affect AbiA activity. Replacement of L242 with an alanine elimination phage resistance against phi 31, but partial resistance to sk1 and c2 remained. Two single proline substitutions for leucines L242 and L263 virtually eliminated AbiA activity against all phages, indicating that the predicted alpha-helical structure of this region is important. Mutations in an adjacent region of basic amino acids had various effects on phage resistance, suggesting that these basic residues are also important for AbiA activity. This directed mutagenesis analysis of AbiA indicated that the leucine repeat structure is essential for conferring phage resistance against three species of lactococcal bacteriophages.

Injected phage-displayed-VP28 vaccine reduces shrimp Litopenaeus vannamei mortality by white spot syndrome virus infection.

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Solís-Lucero, G; Manoutcharian, K; Hernández-López, J; Ascencio, F

2016-08-01

White spot syndrome virus (WSSV) is the most important viral pathogen for the global shrimp industry causing mass mortalities with huge economic losses. Recombinant phages are capable of expressing foreign peptides on viral coat surface and act as antigenic peptide carriers bearing a phage-displayed vaccine. In this study, the full-length VP28 protein of WSSV, widely known as potential vaccine against infection in shrimp, was successfully cloned and expressed on M13 filamentous phage. The functionality and efficacy of this vaccine immunogen was demonstrated through immunoassay and in vivo challenge studies. In ELISA assay phage-displayed VP28 was bind to Litopenaeus vannamei immobilized hemocyte in contrast to wild-type M13 phage. Shrimps were injected with 2 × 10(10) cfu animal(-1) single dose of VP28-M13 and M13 once and 48 h later intramuscularly challenged with WSSV to test the efficacy of the vaccine against the infection. All dead challenged shrimps were PCR WSSV-positive. The accumulative mortality of the vaccinated and challenged shrimp groups was significantly lower (36.67%) than the unvaccinated group (66.67%). Individual phenoloxidase and superoxide dismutase activity was assayed on 8 and 48 h post-vaccination. No significant difference was found in those immunological parameters among groups at any sampled time evaluated. For the first time, phage display technology was used to express a recombinant vaccine for shrimp. The highest percentage of relative survival in vaccinated shrimp (RPS = 44.99%) suggest that the recombinant phage can be used successfully to display and deliver VP28 for farmed marine crustaceans. Copyright © 2016 Elsevier Ltd. All rights reserved.

An improved plating assay for determination of phage titer

African Journals Online (AJOL)

RACHEL

antibiotics to control bacterial infections in swine (Thacker,. 2014). Phage therapy is re-valued by researchers to combat the growing menace of antibiotic-resistant infections (Torres-Barceló and Hochberg, 2016). Determination of phage titer in a sample is a key step in the study of the phage involved. It is very important to.

Genes Required for Free Phage Production are Essential for Pseudomonas aeruginosa Chronic Lung Infections.

Science.gov (United States)

Lemieux, Andrée-Ann; Jeukens, Julie; Kukavica-Ibrulj, Irena; Fothergill, Joanne L; Boyle, Brian; Laroche, Jérôme; Tucker, Nicholas P; Winstanley, Craig; Levesque, Roger C

2016-02-01

The opportunistic pathogen Pseudomonas aeruginosa causes chronic lung infection in patients with cystic fibrosis. The Liverpool Epidemic Strain LESB58 is highly resistant to antibiotics, transmissible, and associated with increased morbidity and mortality. Its genome contains 6 prophages and 5 genomic islands. We constructed a polymerase chain reaction (PCR)-based signature-tagged mutagenesis library of 9216 LESB58 mutants and screened the mutants in a rat model of chronic lung infection. A total of 162 mutants were identified as defective for in vivo maintenance, with 11 signature-tagged mutagenesis mutants having insertions in prophage and genomic island genes. Many of these mutants showed both diminished virulence and reduced phage production. Transcription profiling by quantitative PCR and RNA-Seq suggested that disruption of these prophages had a widespread trans-acting effect on the transcriptome. This study demonstrates that temperate phages play a pivotal role in the establishment of infection through modulation of bacterial host gene expression. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Concomitant infection of Neospora caninum and Bovine Herpesvirus type 5 in spontaneous bovine abortions

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Maia S. Marin

2013-11-01

Full Text Available Bovine Herpesvirus type 5 (BoHV-5 has not been conclusively demonstrated to cause bovine abortion. Brain lesions produced by Neospora caninum and Bovine Herpesvirus type 1 (BoHV-1 exhibit common features. Therefore, careful microscopic evaluation and additional diagnostic procedures are required to achieve an accurate final etiological diagnosis. The aim of the present work was to investigate the occurrence of infections due to BoHV-1, BoHV-5 and N. caninum in 68 cases of spontaneous bovine abortions which showed microscopic lesions in the fetal central nervous system. This study allowed the identification of 4 (5.9% fetuses with dual infection by BoHV-5 and N. caninum and 33 (48.5% cases in which N. caninum was the sole pathogen identified. All cases were negative to BoHV-1. The results of this study provide evidence that dual infection by BoHV-5 and N. caninum occur during pregnancy in cattle; however, the role of BoHV-5 as a primary cause of bovine abortion needs further research. Molecular diagnosis of BoHV-5 and N. caninum confirmed the importance of applying complementary assays to improve the sensitivity of diagnosing bovine abortion.

Exploring the Effect of Phage Therapy in Preventing Vibrio anguillarum Infections in Cod and Turbot Larvae

DEFF Research Database (Denmark)

Rørbo, Nanna; Rønneseth, Anita; Kalatzis, Panos G.

2018-01-01

The aquaculture industry is suffering from losses associated with bacterial infections by opportunistic pathogens. Vibrio anguillarum is one of the most important pathogens, causing vibriosis in fish and shellfish cultures leading to high mortalities and economic losses. Bacterial resistance to a...... KVP40, demonstrating that the phage could also reduce mortality imposed by the background population of pathogens. Overall, phage-mediated reduction in mortality of cod and turbot larvae in experimental challenge assays with V. anguillarum pathogens suggested that application of broad...

Restoring logic and data to phage-cures for infectious disease

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Philip Serwer

2017-08-01

Full Text Available Antibiotic therapy for infectious disease is being compromised by emergence of multi-drug-resistant bacterial strains, often called superbugs. A response is to use a cocktail of several bacteria-infecting viruses (bacteriophages or phages to supplement antibiotic therapy. Use of such cocktails is called phage therapy, which has the advantage of response to bacterial resistance that is rapid and not exhaustible. A procedure of well-established success is to make cocktails from stockpiles of stored environmental phages. New phages are added to stockpiles when phage therapy becomes thwarted. The scientific subtext includes optimizing the following aspects: (1 procedure for rapidly detecting, purifying, storing and characterizing phages for optimization of phage cocktails, (2 use of directed evolution in the presence of bacteriostatic compounds to obtain phages that can be most efficiently used for therapy in the presence of these compounds, (3 phage genome sequencing technology and informatics to improve the characterization of phages, and (4 database technology to make optimal use of all relevant information and to rapidly retrieve phages for cocktails that will vary with the infection(s involved. The use of phage stockpiles has an established record, including a recent major human-therapy success by the US Navy. However, I conclude that most research is not along this track and, therefore, is not likely to lead to real world success. I find that a strong case exists for action to rectify this situation.

The phage-host arms race: Shaping the evolution of microbes

Energy Technology Data Exchange (ETDEWEB)

Stern, Adi [Weizmann Inst. of Science, Rehovot (Israel). Dept. of Molecular Genetics; Sorek, Rotem [Weizmann Inst. of Science, Rehovot (Israel). Dept. of Molecular Genetics

2010-10-26

Bacteria, the most abundant organisms on the planet, are outnumbered by a factor of 10 to 1 by phages that infect them. Faced with the rapid evolution and turnover of phage particles, bacteria have evolved various mechanisms to evade phage infection and killing, leading to an evolutionary arms race. The extensive co-evolution of both phage and host has resulted in considerable diversity on the part of both bacterial and phage defensive and offensive strategies. In this paper, we discuss the unique and common features of phage resistance mechanisms and their role in global biodiversity. Finally, the commonalities between defense mechanisms suggest avenues for the discovery of novel forms of these mechanisms based on their evolutionary traits.

Primary isolation strain determines both phage type and receptors recognised by Campylobacter jejuni bacteriophages.

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Martine C Holst Sørensen

Full Text Available In this study we isolated novel bacteriophages, infecting the zoonotic bacterium Campylobacter jejuni. These phages may be used in phage therapy of C. jejuni colonized poultry to prevent spreading of the bacteria to meat products causing disease in humans. Many C. jejuni phages have been isolated using NCTC12662 as the indicator strain, which may have biased the selection of phages. A large group of C. jejuni phages rely on the highly diverse capsular polysaccharide (CPS for infection and recent work identified the O-methyl phosphoramidate modification (MeOPN of CPS as a phage receptor. We therefore chose seven C. jejuni strains each expressing different CPS structures as indicator strains in a large screening for phages in samples collected from free-range poultry farms. Forty-three phages were isolated using C. jejuni NCTC12658, NCTC12662 and RM1221 as host strains and 20 distinct phages were identified based on host range analysis and genome restriction profiles. Most phages were isolated using C. jejuni strains NCTC12662 and RM1221 and interestingly phage genome size (140 kb vs. 190 kb, host range and morphological appearance correlated with the isolation strain. Thus, according to C. jejuni phage grouping, NCTC12662 and NCTC12658 selected for CP81-type phages, while RM1221 selected for CP220-type phages. Furthermore, using acapsular ∆kpsM mutants we demonstrated that phages isolated on NCTC12658 and NCTC12662 were dependent on the capsule for infection. In contrast, CP220-type phages isolated on RM1221 were unable to infect non-motile ∆motA mutants, hence requiring motility for successful infection. Hence, the primary phage isolation strain determines both phage type (CP81 or CP220 as well as receptors (CPS or flagella recognised by the isolated phages.

Survival and mutagenesis in UV-irradiated phage: Multi-hit kinetics of mutation induction and lack of indirect induction by infection with UV-irradiated phage of error-prone repair

International Nuclear Information System (INIS)

Krauss, G.; Mennigmann, H.D.; Kaplan, R.W.

1980-01-01

The paper is concerned with the question of whether Weigle-reactivation (WR) and Weigle-mutagenesis (WM) can be indirectly induced by infection with UV-irradiated phage. Experiments neither with phage lambda of Escherichia coli nor with phage kappa of Serratia marcescens show such induction. In this respect phage DNA differs from F'-DNA or Hfr-DNA; possible explanations are discussed. In both systems clear plaque mutations can also be induced by UV without irradiation of the host cells; they appear, in unirradiated and irradiated host cells, with an increase in frequency which is greater than proportional to the UV dose. It is concluded that mutation induction of phage in the unirradiated host cells is due to a low level constitutive mutagenic repair; this could either be due to 'spontaneous' induction of the mutagenic SOS function or it could be a mechanism different from this one. Host irradiation would give rise to additional activity by the induced SOS function leading to WR and WM. It is further concluded that deviation of the induction kinetics from a linear dose-dependence is not due to the necessary induction of SOS functions. (author)

Phage therapy is effective against infection by Mycobacterium ulcerans in a murine footpad model.

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Gabriela Trigo

Full Text Available BACKGROUND: Buruli Ulcer (BU is a neglected, necrotizing skin disease caused by Mycobacterium ulcerans. Currently, there is no vaccine against M. ulcerans infection. Although the World Health Organization recommends a combination of rifampicin and streptomycin for the treatment of BU, clinical management of advanced stages is still based on the surgical resection of infected skin. The use of bacteriophages for the control of bacterial infections has been considered as an alternative or to be used in association with antibiotherapy. Additionally, the mycobacteriophage D29 has previously been shown to display lytic activity against M. ulcerans isolates. METHODOLOGY/PRINCIPAL FINDINGS: We used the mouse footpad model of M. ulcerans infection to evaluate the therapeutic efficacy of treatment with mycobacteriophage D29. Analyses of macroscopic lesions, bacterial burdens, histology and cytokine production were performed in both M. ulcerans-infected footpads and draining lymph nodes (DLN. We have demonstrated that a single subcutaneous injection of the mycobacteriophage D29, administered 33 days after bacterial challenge, was sufficient to decrease pathology and to prevent ulceration. This protection resulted in a significant reduction of M. ulcerans numbers accompanied by an increase of cytokine levels (including IFN-γ, both in footpads and DLN. Additionally, mycobacteriophage D29 treatment induced a cellular infiltrate of a lymphocytic/macrophagic profile. CONCLUSIONS/SIGNIFICANCE: Our observations demonstrate the potential of phage therapy against M. ulcerans infection, paving the way for future studies aiming at the development of novel phage-related therapeutic approaches against BU.

The habits of highly effective phages: population dynamics as a framework for identifying therapeutic phages

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James J Bull

2014-11-01

Full Text Available The use of bacteriophages as antibacterial agents is being actively researched on a global scale. Typically, the phages used are isolated from the wild by plating on the bacteria of interest, and a far larger set of candidate phages is often available than can be used in any application. When an excess of phages is available, how should the best phages be identified? Here we consider phage-bacterial population dynamics as a basis for evaluating and predicting phage success. A central question is whether the innate dynamical properties of phages are the determinants of success, or instead, whether extrinsic, indirect effects can be responsible. We address the dynamical perspective, motivated in part by the absence of dynamics in previously suggested principles of phage therapy. Current mathematical models of bacterial-phage dynamics do not capture the realities of in vivo dynamics, nor is this likely to change, but they do give insight to qualitative properties that may be generalizable. In particular, phage adsorption rate may be critical to treatment success, so understanding the effects of the in vivo environment on host availability may allow prediction of useful phages prior to in vivo experimentation. Principles for predicting efficacy may be derived by developing a greater understanding of the in vivo system, or such principles could be determined empirically by comparing phages with known differences in their dynamic properties. The comparative approach promises to be a powerful method of discovering the key to phage success. We offer five recommendations for future study: (i compare phages differing in treatment efficacy to identify the phage properties associated with success, (ii assay dynamics in vivo, (iii understand mechanisms of bacterial escape from phages, (iv test phages in model infections that are relevant to the intended clinical applications, and (v develop new classes of models for phage growth in spatially heterogeneous

Exploration of Phage-Host Interactions in Fish Pathogen Vibrio anguillarum and Anti-Phage Defense Strategies

DEFF Research Database (Denmark)

Tan, Demeng

The disease vibriosis is caused by the bacterial pathogen Vibrio anguillarum and results in large losses in aquaculture both in Denmark and around the world. Antibiotics have been widely used in antimicrobial prophylaxis and treatment of vibriosis. Recently, numerous multidrug-resistant strains...... of V. anguillarum have been isolated, indicating that antibiotic use has to be restricted and alternatives have to be developed. Lytic phages have been demonstrated to play an essential role in preventing bacterial infection. However, phages are also known to play a critical role in the evolution...... of bacterial pathogenicity development. Therefore, successful application of phage therapy in the treatment of vibriosis requires a detailed understanding of phage-host interactions, especially with regards to anti-phage defense mechanisms in the host. Part I. As a first approach, 24 V. anguillarum and 13...

Phage inhibit pathogen dissemination by targeting bacterial migrants in a chronic infection model

DEFF Research Database (Denmark)

Darch, Sophie E.; Kragh, Kasper N.; Abbott, Evelyn A.

2017-01-01

The microbial communities inhabiting chronic infections are often composed of spatially organized micrometer-sized, highly dense aggregates. It has recently been hypothesized that aggregates are responsible for the high tolerance of chronic infections to host immune functions and antimicrobial...... production; however, seeding of new aggregates by dispersed migrants was inhibited. We propose a model in which aggregates provide a mechanism that allows P. aeruginosa to tolerate phage therapy during chronic infection without the need for genetic mutation. IMPORTANCE Bacteria in chronic infections often...... reside in communities composed of micrometer-sized, highly dense aggregates. A primary challenge for studying aggregates has been the lack of laboratory systems that promote natural aggregate formation in relevant environments. Here, we developed a growth medium that mimics chronic lung infection...

Vibrio vulnificus phage PV94 is closely related to temperate phages of V. cholerae and other Vibrio species.

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Mark Pryshliak

Full Text Available BACKGROUND: Vibrio vulnificus is an important pathogen which can cause serious infections in humans. Yet, there is limited knowledge on its virulence factors and the question whether temperate phages might be involved in pathogenicity, as is the case with V. cholerae. Thus far, only two phages (SSP002 and VvAW1 infecting V. vulnificus have been genetically characterized. These phages were isolated from the environment and are not related to Vibrio cholerae phages. The lack of information on temperate V. vulnificus phages prompted us to isolate those phages from lysogenic strains and to compare them with phages of other Vibrio species. RESULTS: In this study the temperate phage PV94 was isolated from a V. vulnificus biotype 1 strain by mitomycin C induction. PV94 is a myovirus whose genome is a linear double-stranded DNA of 33,828 bp with 5'-protruding ends. Sequence analysis of PV94 revealed a modular organization of the genome. The left half of the genome comprising the immunity region and genes for the integrase, terminase and replication proteins shows similarites to V. cholerae kappa phages whereas the right half containing genes for structural proteins is closely related to a prophage residing in V. furnissii NCTC 11218. CONCLUSION: We present the first genomic sequence of a temperate phage isolated from a human V. vulnificus isolate. The sequence analysis of the PV94 genome demonstrates the wide distribution of closely related prophages in various Vibrio species. Moreover, the mosaicism of the PV94 genome indicates a high degree of horizontal genetic exchange within the genus Vibrio, by which V. vulnificus might acquire virulence-associated genes from other species.

Phage therapy reduces Campylobacter jejuni colonization in broilers

NARCIS (Netherlands)

Wagenaar, J.A.; Bergen, van M.A.P.; Mueller, M.A.; Wassenaar, T.M.; Carlton, R.M.

2005-01-01

The effect of phage therapy in the control of Campylobacter jejuni colonization in young broilers, either as a preventive or a therapeutic measure, was tested. A prevention group was infected with C. jejuni at day 4 of a 10-day phage treatment. A therapeutic group was phage treated for 6 days,

A highly specific phage defense system is a conserved feature of the Vibrio cholerae mobilome.

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Brendan J O'Hara

2017-06-01

Full Text Available Vibrio cholerae-specific bacteriophages are common features of the microbial community during cholera infection in humans. Phages impose strong selective pressure that favors the expansion of phage-resistant strains over their vulnerable counterparts. The mechanisms allowing virulent V. cholerae strains to defend against the ubiquitous threat of predatory phages have not been established. Here, we show that V. cholerae PLEs (phage-inducible chromosomal island-like elements are widespread genomic islands dedicated to phage defense. Analysis of V. cholerae isolates spanning a 60-year collection period identified five unique PLEs. Remarkably, we found that all PLEs (regardless of geographic or temporal origin respond to infection by a myovirus called ICP1, the most prominent V. cholerae phage found in cholera patient stool samples from Bangladesh. We found that PLE activity reduces phage genome replication and accelerates cell lysis following ICP1 infection, killing infected host cells and preventing the production of progeny phage. PLEs are mobilized by ICP1 infection and can spread to neighboring cells such that protection from phage predation can be horizontally acquired. Our results reveal that PLEs are a persistent feature of the V. cholerae mobilome that are adapted to providing protection from a single predatory phage and advance our understanding of how phages influence pathogen evolution.

A highly specific phage defense system is a conserved feature of the Vibrio cholerae mobilome.

Science.gov (United States)

O'Hara, Brendan J; Barth, Zachary K; McKitterick, Amelia C; Seed, Kimberley D

2017-06-01

Vibrio cholerae-specific bacteriophages are common features of the microbial community during cholera infection in humans. Phages impose strong selective pressure that favors the expansion of phage-resistant strains over their vulnerable counterparts. The mechanisms allowing virulent V. cholerae strains to defend against the ubiquitous threat of predatory phages have not been established. Here, we show that V. cholerae PLEs (phage-inducible chromosomal island-like elements) are widespread genomic islands dedicated to phage defense. Analysis of V. cholerae isolates spanning a 60-year collection period identified five unique PLEs. Remarkably, we found that all PLEs (regardless of geographic or temporal origin) respond to infection by a myovirus called ICP1, the most prominent V. cholerae phage found in cholera patient stool samples from Bangladesh. We found that PLE activity reduces phage genome replication and accelerates cell lysis following ICP1 infection, killing infected host cells and preventing the production of progeny phage. PLEs are mobilized by ICP1 infection and can spread to neighboring cells such that protection from phage predation can be horizontally acquired. Our results reveal that PLEs are a persistent feature of the V. cholerae mobilome that are adapted to providing protection from a single predatory phage and advance our understanding of how phages influence pathogen evolution.

Filamentous phages of Ralstonia solanacearum: double-edged swords for pathogenic bacteria.

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Yamada, Takashi

2013-01-01

Some phages from genus Inovirus use host or bacteriophage-encoded site-specific integrases or recombinases establish a prophage state. During integration or excision, a superinfective form can be produced. The three states (free, prophage, and superinfective) of such phages exert different effects on host bacterial phenotypes. In Ralstonia solanacearum, the causative agent of bacterial wilt disease of crops, the bacterial virulence can be positively or negatively affected by filamentous phages, depending on their state. The presence or absence of a repressor gene in the phage genome may be responsible for the host phenotypic differences (virulent or avirulent) caused by phage infection. This strategy of virulence control may be widespread among filamentous phages that infect pathogenic bacteria of plants.

Metagenomic recovery of phage genomes of uncultured freshwater actinobacteria.

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Ghai, Rohit; Mehrshad, Maliheh; Mizuno, Carolina Megumi; Rodriguez-Valera, Francisco

2017-01-01

Low-GC Actinobacteria are among the most abundant and widespread microbes in freshwaters and have largely resisted all cultivation efforts. Consequently, their phages have remained totally unknown. In this work, we have used deep metagenomic sequencing to assemble eight complete genomes of the first tailed phages that infect freshwater Actinobacteria. Their genomes encode the actinobacterial-specific transcription factor whiB, frequently found in mycobacteriophages and also in phages infecting marine pelagic Actinobacteria. Its presence suggests a common and widespread strategy of modulation of host transcriptional machinery upon infection via this transcriptional switch. We present evidence that some whiB-carrying phages infect the acI lineage of Actinobacteria. At least one of them encodes the ADP-ribosylating component of the widespread bacterial AB toxins family (for example, clostridial toxin). We posit that the presence of this toxin reflects a 'trojan horse' strategy, providing protection at the population level to the abundant host microbes against eukaryotic predators.

A randomised controlled trial of prophylaxis of post-abortal infection: ceftriaxone versus placebo

DEFF Research Database (Denmark)

Henriques, C U; Wilken-Jensen, C; Thorsen, P

1994-01-01

days postoperatively, underwent pelvic examination. Clinical endpoints were noted. MAIN OUTCOME MEASURES: Post-operative pelvic inflammatory disease in women applying for legal first trimester abortion. RESULTS: Seven hundred and eighty-six women fulfilled the criteria for evaluation. A tendency toward...... for legal first trimester abortion, treated peroperatively with ceftriaxone. No significant difference was demonstrated between high risk patients treated with ceftriaxone or ampicillin/pivampicillin and metronidazole. Udgivelsesdato: 1994-Jul......OBJECTIVE: To investigate the incidence of post-operative infection after first trimester abortion in women treated with a long-acting cephalosporin (ceftriaxone) compared with low risk patients receiving no treatment and with high risk patients receiving our standard treatment of ampicillin...

A Genotypic Analysis of Five P. aeruginosa Strains after Biofilm Infection by Phages Targeting Different Cell Surface Receptors

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Diana P. Pires

2017-06-01

Full Text Available Antibiotic resistance constitutes one of the most serious threats to the global public health and urgently requires new and effective solutions. Bacteriophages are bacterial viruses increasingly recognized as being good alternatives to traditional antibiotic therapies. In this study, the efficacy of phages, targeting different cell receptors, against Pseudomonas aeruginosa PAO1 biofilm and planktonic cell cultures was evaluated over the course of 48 h. Although significant reductions in the number of viable cells were achieved for both cases, the high level of adaptability of the bacteria in response to the selective pressure caused by phage treatment resulted in the emergence of phage-resistant variants. To further investigate the genetic makeup of phage-resistant variants isolated from biofilm infection experiments, some of these bacteria were selected for phenotypic and genotypic characterization. Whole genome sequencing was performed on five phage-resistant variants and all of them carried mutations affecting the galU gene as well as one of pil genes. The sequencing analysis further revealed that three of the P. aeruginosa PAO1 variants carry large deletions (>200 kbp in their genomes. Complementation of the galU mutants with wild-type galU in trans restored LPS expression on the bacterial cell surface of these bacterial strains and rendered the complemented strains to be sensitive to phages. This provides unequivocal evidence that inactivation of galU function was associated with resistance to the phages that uses LPS as primary receptors. Overall, this work demonstrates that P. aeruginosa biofilms can survive phage attack and develop phage-resistant variants exhibiting defective LPS production and loss of type IV pili that are well adapted to the biofilm mode of growth.

Nongenetic individuality in the host-phage interaction.

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Sivan Pearl

2008-05-01

Full Text Available Isogenic bacteria can exhibit a range of phenotypes, even in homogeneous environmental conditions. Such nongenetic individuality has been observed in a wide range of biological processes, including differentiation and stress response. A striking example is the heterogeneous response of bacteria to antibiotics, whereby a small fraction of drug-sensitive bacteria can persist under extensive antibiotic treatments. We have previously shown that persistent bacteria enter a phenotypic state, identified by slow growth or dormancy, which protects them from the lethal action of antibiotics. Here, we studied the effect of persistence on the interaction between Escherichia coli and phage lambda. We used long-term time-lapse microscopy to follow the expression of green fluorescent protein (GFP under the phage lytic promoter, as well as cellular fate, in single infected bacteria. Intriguingly, we found that, whereas persistent bacteria are protected from prophage induction, they are not protected from lytic infection. Quantitative analysis of gene expression reveals that the expression of lytic genes is suppressed in persistent bacteria. However, when persistent bacteria switch to normal growth, the infecting phage resumes the process of gene expression, ultimately causing cell lysis. Using mathematical models for these two host-phage interactions, we found that the bacteria's nongenetic individuality can significantly affect the population dynamics, and might be relevant for understanding the coevolution of bacterial hosts and phages.

Characterizing Phage Genomes for Therapeutic Applications

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Casandra W. Philipson

2018-04-01

Full Text Available Multi-drug resistance is increasing at alarming rates. The efficacy of phage therapy, treating bacterial infections with bacteriophages alone or in combination with traditional antibiotics, has been demonstrated in emergency cases in the United States and in other countries, however remains to be approved for wide-spread use in the US. One limiting factor is a lack of guidelines for assessing the genomic safety of phage candidates. We present the phage characterization workflow used by our team to generate data for submitting phages to the Federal Drug Administration (FDA for authorized use. Essential analysis checkpoints and warnings are detailed for obtaining high-quality genomes, excluding undesirable candidates, rigorously assessing a phage genome for safety and evaluating sequencing contamination. This workflow has been developed in accordance with community standards for high-throughput sequencing of viral genomes as well as principles for ideal phages used for therapy. The feasibility and utility of the pipeline is demonstrated on two new phage genomes that meet all safety criteria. We propose these guidelines as a minimum standard for phages being submitted to the FDA for review as investigational new drug candidates.

Characterizing Phage Genomes for Therapeutic Applications.

Science.gov (United States)

Philipson, Casandra W; Voegtly, Logan J; Lueder, Matthew R; Long, Kyle A; Rice, Gregory K; Frey, Kenneth G; Biswas, Biswajit; Cer, Regina Z; Hamilton, Theron; Bishop-Lilly, Kimberly A

2018-04-10

Multi-drug resistance is increasing at alarming rates. The efficacy of phage therapy, treating bacterial infections with bacteriophages alone or in combination with traditional antibiotics, has been demonstrated in emergency cases in the United States and in other countries, however remains to be approved for wide-spread use in the US. One limiting factor is a lack of guidelines for assessing the genomic safety of phage candidates. We present the phage characterization workflow used by our team to generate data for submitting phages to the Federal Drug Administration (FDA) for authorized use. Essential analysis checkpoints and warnings are detailed for obtaining high-quality genomes, excluding undesirable candidates, rigorously assessing a phage genome for safety and evaluating sequencing contamination. This workflow has been developed in accordance with community standards for high-throughput sequencing of viral genomes as well as principles for ideal phages used for therapy. The feasibility and utility of the pipeline is demonstrated on two new phage genomes that meet all safety criteria. We propose these guidelines as a minimum standard for phages being submitted to the FDA for review as investigational new drug candidates.

Twelve previously unknown phage genera are ubiquitous in global oceans.

Science.gov (United States)

Holmfeldt, Karin; Solonenko, Natalie; Shah, Manesh; Corrier, Kristen; Riemann, Lasse; Verberkmoes, Nathan C; Sullivan, Matthew B

2013-07-30

Viruses are fundamental to ecosystems ranging from oceans to humans, yet our ability to study them is bottlenecked by the lack of ecologically relevant isolates, resulting in "unknowns" dominating culture-independent surveys. Here we present genomes from 31 phages infecting multiple strains of the aquatic bacterium Cellulophaga baltica (Bacteroidetes) to provide data for an underrepresented and environmentally abundant bacterial lineage. Comparative genomics delineated 12 phage groups that (i) each represent a new genus, and (ii) represent one novel and four well-known viral families. This diversity contrasts the few well-studied marine phage systems, but parallels the diversity of phages infecting human-associated bacteria. Although all 12 Cellulophaga phages represent new genera, the podoviruses and icosahedral, nontailed ssDNA phages were exceptional, with genomes up to twice as large as those previously observed for each phage type. Structural novelty was also substantial, requiring experimental phage proteomics to identify 83% of the structural proteins. The presence of uncommon nucleotide metabolism genes in four genera likely underscores the importance of scavenging nutrient-rich molecules as previously seen for phages in marine environments. Metagenomic recruitment analyses suggest that these particular Cellulophaga phages are rare and may represent a first glimpse into the phage side of the rare biosphere. However, these analyses also revealed that these phage genera are widespread, occurring in 94% of 137 investigated metagenomes. Together, this diverse and novel collection of phages identifies a small but ubiquitous fraction of unknown marine viral diversity and provides numerous environmentally relevant phage-host systems for experimental hypothesis testing.

In Vivo Assessment of Phage and Linezolid Based Implant Coatings for Treatment of Methicillin Resistant S. aureus (MRSA Mediated Orthopaedic Device Related Infections.

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Sandeep Kaur

Full Text Available Staphylococcus comprises up to two-thirds of all pathogens in orthopaedic implant infections with two species respectively Staphylococcus aureus and Staphylococcus epidermidis, being the predominate etiological agents isolated. Further, with the emergence of methicillin-resistant S. aureus (MRSA, treatment of S. aureus implant infections has become more difficult, thus representing a devastating complication. Use of local delivery system consisting of S.aureus specific phage along with linezolid (incorporated in biopolymer allowing gradual release of the two agents at the implant site represents a new, still unexplored treatment option (against orthopaedic implant infections that has been studied in an animal model of prosthetic joint infection. Naked wire, hydroxypropyl methylcellulose (HPMC coated wire and phage and /or linezolid coated K-wire were surgically implanted into the intra-medullary canal of mouse femur bone of respective groups followed by inoculation of S.aureus ATCC 43300(MRSA. Mice implanted with K-wire coated with both the agents i.e phage as well as linezolid (dual coated wires showed maximum reduction in bacterial adherence, associated inflammation of the joint as well as faster resumption of locomotion and motor function of the limb. Also, all the coating treatments showed no emergence of resistant mutants. Use of dual coated implants incorporating lytic phage (capable of self-multiplication as well as linezolid presents an attractive and aggressive early approach in preventing as well as treating implant associated infections caused by methicillin resistant S. aureus strains as assessed in a murine model of experimental joint infection.

Phage Therapy Is Effective in a Mouse Model of Bacterial Equine Keratitis.

Science.gov (United States)

Furusawa, Takaaki; Iwano, Hidetomo; Hiyashimizu, Yutaro; Matsubara, Kazuki; Higuchi, Hidetoshi; Nagahata, Hajime; Niwa, Hidekazu; Katayama, Yoshinari; Kinoshita, Yuta; Hagiwara, Katsuro; Iwasaki, Tomohito; Tanji, Yasunori; Yokota, Hiroshi; Tamura, Yutaka

2016-09-01

Bacterial keratitis of the horse is mainly caused by staphylococci, streptococci, and pseudomonads. Of these bacteria, Pseudomonas aeruginosa sometimes causes rapid corneal corruption and, in some cases, blindness. Antimicrobial resistance can make treatment very difficult. Therefore, new strategies to control bacterial infection are required. A bacteriophage (phage) is a virus that specifically infects and kills bacteria. Since phage often can lyse antibiotic-resistant bacteria because the killing mechanism is different, we examined the use of phage to treat horse bacterial keratitis. We isolated Myoviridae or Podoviridae phages, which together have a broad host range. They adsorb efficiently to host bacteria; more than 80% of the ΦR18 phage were adsorbed to host cells after 30 s. In our keratitis mouse model, the administration of phage within 3 h also could kill bacteria and suppress keratitis. A phage multiplicity of infection of 100 times the host bacterial number could kill host bacteria effectively. A cocktail of two phages suppressed bacteria in the keratitis model mouse. These data demonstrated that the phages in this study could completely prevent the keratitis caused by P. aeruginosa in a keratitis mouse model. Furthermore, these results suggest that phage may be a more effective prophylaxis for horse keratitis than the current preventive use of antibiotics. Such treatment may reduce the use of antibiotics and therefore antibiotic resistance. Further studies are required to assess phage therapy as a candidate for treatment of horse keratitis. Antibiotic-resistant bacteria are emerging all over the world. Bacteriophages have great potential for resolution of this problem. A bacteriophage, or phage, is a virus that infects bacteria specifically. As a novel therapeutic strategy against racehorse keratitis caused by Pseudomonas aeruginosa, we propose the application of phages for treatment. Phages isolated in this work had in vitro effectiveness for a broad

Complete genome sequences of three Campylobacter jejuni phage-propagating strains

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Bacteriophage therapy has the potential to reduce Campylobacter jejuni numbers in livestock, but requires a detailed understanding of phage-host interactions. Some C. jejuni strains are readily infected by certain phages, and are thus designated as phage-propagating strains. Here we report the compl...

Pseudomonas predators: understanding and exploiting phage-host interactions.

Science.gov (United States)

De Smet, Jeroen; Hendrix, Hanne; Blasdel, Bob G; Danis-Wlodarczyk, Katarzyna; Lavigne, Rob

2017-09-01

Species in the genus Pseudomonas thrive in a diverse set of ecological niches and include crucial pathogens, such as the human pathogen Pseudomonas aeruginosa and the plant pathogen Pseudomonas syringae. The bacteriophages that infect Pseudomonas spp. mirror the widespread and diverse nature of their hosts. Therefore, Pseudomonas spp. and their phages are an ideal system to study the molecular mechanisms that govern virus-host interactions. Furthermore, phages are principal catalysts of host evolution and diversity, which directly affects the ecological roles of environmental and pathogenic Pseudomonas spp. Understanding these interactions not only provides novel insights into phage biology but also advances the development of phage therapy, phage-derived antimicrobial strategies and innovative biotechnological tools that may be derived from phage-bacteria interactions.

Phage therapy against Enterococcus faecalis in dental root canals

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Leron Khalifa

2016-09-01

Full Text Available Antibiotic resistance is an ever-growing problem faced by all major sectors of health care, including dentistry. Recurrent infections related to multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus, carbapenem-resistant Enterobacteriaceae, and vancomycin-resistant enterococci (VRE in hospitals are untreatable and question the effectiveness of notable drugs. Two major reasons for these recurrent infections are acquired antibiotic resistance genes and biofilm formation. None of the traditionally known effective techniques have been able to efficiently resolve these issues. Hence, development of a highly effective antibacterial practice has become inevitable. One example of a hard-to-eradicate pathogen in dentistry is Enterococcus faecalis, which is one of the most common threats observed in recurrent root canal treatment failures, of which the most problematic to treat are its biofilm-forming VRE strains. An effective response against such infections could be the use of bacteriophages (phages. Phage therapy was found to be highly effective against biofilm and multidrug-resistant bacteria and has other advantages like ease of isolation and possibilities for genetic manipulations. The potential of phage therapy in dentistry, in particular against E. faecalis biofilms in root canals, is almost unexplored. Here we review the efforts to develop phage therapy against biofilms. We also focus on the phages isolated against E. faecalis and discuss the possibility of using phages against E. faecalis biofilm in root canals.

Characterization, Genome Sequence, and Analysis of Escherichia Phage CICC 80001, a Bacteriophage Infecting an Efficient L-Aspartic Acid Producing Escherichia coli.

Science.gov (United States)

Xu, Youqiang; Ma, Yuyue; Yao, Su; Jiang, Zengyan; Pei, Jiangsen; Cheng, Chi

2016-03-01

Escherichia phage CICC 80001 was isolated from the bacteriophage contaminated medium of an Escherichia coli strain HY-05C (CICC 11022S) which could produce L-aspartic acid. The phage had a head diameter of 45-50 nm and a tail of about 10 nm. The one-step growth curve showed a latent period of 10 min and a rise period of about 20 min. The average burst size was about 198 phage particles per infected cell. Tests were conducted on the plaques, multiplicity of infection, and host range. The genome of CICC 80001 was sequenced with a length of 38,810 bp, and annotated. The key proteins leading to host-cell lysis were phylogenetically analyzed. One protein belonged to class II holin, and the other two belonged to the endopeptidase family and N-acetylmuramoyl-L-alanine amidase family, respectively. The genome showed the sequence identity of 82.7% with that of Enterobacteria phage T7, and carried ten unique open reading frames. The bacteriophage resistant E. coli strain designated CICC 11021S was breeding and its L-aspartase activity was 84.4% of that of CICC 11022S.

The global reciprocal reprogramming between mycobacteriophage SWU1 and mycobacterium reveals the molecular strategy of subversion and promotion of phage infection

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Xiangyu eFan

2016-01-01

Full Text Available Bacteriophages are the viruses of bacteria, which have contributed extensively to our understanding of life and modern biology. The phage-mediated bacterial growth inhibition represents immense untapped source for novel antimicrobials. Insights into the interaction between mycobacteriophage and Mycobacterium host will inform better utilizing of mycobacteriophage. In this study, RNA sequencing technology (RNA-seq was used to explore the global response of Mycobacterium smegmatis mc2 155 at an early phase of infection with mycobacteriophage SWU1, key host metabolic processes of M. smegmatis mc2 155 shut off by SWU1, and the responsible phage proteins. The results of RNA-seq were confirmed by Real-time PCR and functional assay. 1174 genes of M. smegmatis mc2 155 (16.9% of the entire encoding capacity were differentially regulated by phage infection. These genes belong to six functional categories: (i signal transduction, (ii cell energetics, (iii cell wall biosynthesis, (iv DNA, RNA, and protein biosynthesis, (v iron uptake, (vi central metabolism. The transcription patterns of phage SWU1 were also characterized. This study provided the first global glimpse of the reciprocal reprogramming between the mycobacteriophage and Mycobacterium host.

Influence of environmental factors on phage-bacteria interaction and on the efficacy and infectivity of phage P100

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Susanne Fister

2016-07-01

Full Text Available When using bacteriophages to control food-borne bacteria in food production plants and processed food, it is crucial to consider that environmental conditions influence their stability. These conditions can also affect the physiological state of bacteria and consequently host-virus interaction and the effectiveness of the phage ability to reduce bacteria numbers. In this study we investigated the stability, binding and replication capability of phage P100 and its efficacy to control L. monocytogenes under conditions typically encountered in dairy plants. The influences of SDS, Lutensol AO 7, salt, smear water and different temperatures were investigated. Results indicate that phage P100 is stable and able to bind to the host under most conditions tested. Replication was dependent upon the growth of L. monocytogenes and efficacy was higher when bacterial growth was reduced by certain environmental conditions. In long-term experiments at different temperatures phages were initially able to reduce bacteria up to seven log10 units after two weeks at 4 °C. However, thereafter re-growth and development of phage-resistant L. monocytogenes isolates were encountered.

Toxoplasma gondii abortion storm in sheep on a Texas farm and isolation of mouse virulent atypical genotype T. gondii from an aborted lamb from a chronically infected ewe

Science.gov (United States)

Sheep are commonly infected with the protozoan parasite, Toxoplasma gondii. Infection may cause early embryonic death and resorption, fetal death and mummification, abortion, stillbirth, and neonatal death. Most sheep acquire T. gondii infection after birth. Recent studies reported that repeat ovine...

The Staphylococci Phages Family: An Overview

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Laurence Van Melderen

2012-11-01

Full Text Available Due to their crucial role in pathogenesis and virulence, phages of Staphylococcus aureus have been extensively studied. Most of them encode and disseminate potent staphylococcal virulence factors. In addition, their movements contribute to the extraordinary versatility and adaptability of this prominent pathogen by improving genome plasticity. In addition to S. aureus, phages from coagulase-negative Staphylococci (CoNS are gaining increasing interest. Some of these species, such as S. epidermidis, cause nosocomial infections and are therefore problematic for public health. This review provides an overview of the staphylococcal phages family extended to CoNS phages. At the morphological level, all these phages characterized so far belong to the Caudovirales order and are mainly temperate Siphoviridae. At the molecular level, comparative genomics revealed an extensive mosaicism, with genes organized into functional modules that are frequently exchanged between phages. Evolutionary relationships within this family, as well as with other families, have been highlighted. All these aspects are of crucial importance for our understanding of evolution and emergence of pathogens among bacterial species such as Staphylococci.

Characterization of Campylobacter phages including analysis of host range by selected Campylobacter Penner serotypes

DEFF Research Database (Denmark)

Hansen, Vinni; Rosenquist, Hanne; Baggesen, Dorte Lau

2007-01-01

range often displayed by phages. To identify the potential of phages as a Campylobacter reducing agent we needed to determine their infectivity on a panel of isolates representing the Campylobacter strains found in broilers as well as humans. Results: In this study, Campylobacter phages were isolated...... from the intestines of broilers and ducks and from abattoir sewage. Twelve phages were investigated to determine their ability to infect the Campylobacter Penner serotypes commonly present in Danish poultry and patients with campylobacteriosis. A total of 89% of the Campylobacter jejuni strains and 14...... range of 12 Danish Campylobacter phages. Due to their ability to infect the majority of the common serotypes in Denmark we suggest the phages can become an effective agent in the effort to reduce the incidence of campylobacteriosis in Denmark. This study provides the basis for future experiments...

A century of the phage: past, present and future.

Science.gov (United States)

Salmond, George P C; Fineran, Peter C

2015-12-01

Viruses that infect bacteria (bacteriophages; also known as phages) were discovered 100 years ago. Since then, phage research has transformed fundamental and translational biosciences. For example, phages were crucial in establishing the central dogma of molecular biology - information is sequentially passed from DNA to RNA to proteins - and they have been shown to have major roles in ecosystems, and help drive bacterial evolution and virulence. Furthermore, phage research has provided many techniques and reagents that underpin modern biology - from sequencing and genome engineering to the recent discovery and exploitation of CRISPR-Cas phage resistance systems. In this Timeline, we discuss a century of phage research and its impact on basic and applied biology.

The Caulobacter crescentus phage phiCbK: genomics of a canonical phage

Directory of Open Access Journals (Sweden)

Gill Jason J

2012-10-01

other described phages, this group is proposed as the founding cohort of a new phage type, the phiCbK-like phages. This work will serve as a foundation for future studies on morphogenesis, infection and phage-host interactions in C. crescentus.

Phages of Listeria offer novel tools for diagnostics and biocontrol

Directory of Open Access Journals (Sweden)

Martin J Loessner

2014-04-01

Full Text Available Historically, bacteriophages infecting their hosts have perhaps been best known and even notorious for being a nuisance in dairy-fermentation processes. However, with the rapid progress in molecular microbiology and microbial ecology, a new dawn has risen for phages. This review will provide an overview on possible uses and applications of Listeria phages, including phage-typing, reporter phage for bacterial diagnostics, and use of phage as biocontrol agents for food safety. The use of phage-encoded enzymes such as endolysins for the detection and as antimicrobial will also be addressed. Desirable properties of candidate phages for biocontrol will be discussed. While emphasizing the enormous future potential for applications, we will also consider some of the intrinsic limitations dictated by both phage and bacterial ecology.

Phage Therapy Approaches to Reducing Pathogen Persistence and Transmission in Animal Production Environments: Opportunities and Challenges.

Science.gov (United States)

Colavecchio, Anna; Goodridge, Lawrence D

2017-06-01

The era of genomics has allowed for characterization of phages for use as antimicrobials to treat animal infections with a level of precision never before realized. As more research in phage therapy has been conducted, several advantages of phage therapy have been realized, including the ubiquitous nature, specificity, prevalence in the biosphere, and low inherent toxicity of phages, which makes them a safe and sustainable technology for control of animal diseases. These unique qualities of phages have led to several opportunities with respect to emerging trends in infectious disease treatment. However, the opportunities are tempered by several challenges to the successful implementation of phage therapy, such as the fact that an individual phage can only infect one or a few bacterial strains, meaning that large numbers of different phages will likely be needed to treat infections caused by multiple species of bacteria. In addition, phages are only effective if enough of them can reach the site of bacterial colonization, but clearance by the immune system upon introduction to the animal is a reality that must be overcome. Finally, bacterial resistance to the phages may develop, resulting in treatment failure. Even a successful phage infection and lysis of its host has consequences, because large amounts of endotoxin are released upon lysis of Gram-negative bacteria, which can lead to local and systemic complications. Overcoming these challenges will require careful design and development of phage cocktails, including comprehensive characterization of phage host range and assessment of immunological risks associated with phage treatment.

DNA damage and mutagenesis of lambda phage induced by gamma-rays

International Nuclear Information System (INIS)

Bertram, Heidi

1988-01-01

Lambda phage DNA was gamma irradiated in aqueous solution and strand breakage determined. Twice as much minor structural damage per lethal hit was found in this DNA compared with DNA from irradiated phage suspensions. The in vitro irradiated DNA was repackaged into infectious particles. Induction of mutations in the cI or cII cistron was scored using SOS-induced host cells. In vitro prepared particles were found to have second-order kinetics for mutagenesis induced by gamma rays indicating two pre-mutational events were necessary to produce a mutation, but bacteria-free phage suspensions ('lys-phage') showed single hit kinetics for mutagenesis after irradiation. Increase in the mutation rate in the phage particles was mainly due to minor lesions, i.e. ssb, als and unidentified base damage. In lys-phage, mutagenesis might be enhanced by clustered DNA damage - configuration not existing in pack-phage. Loss of infectivity was analysed in comparison with structural damage. All lesions contributed to biological inactivation. Minor lesions were tolerated by lambda phage to a limited extent. Major lesions (e.g. dsb) contributed most to infectivity loss and were considered lethal events. (U.K.)

Phages in the Human Body.

Science.gov (United States)

Navarro, Ferran; Muniesa, Maite

2017-01-01

Bacteriophages, viruses that infect bacteria, have re-emerged as powerful regulators of bacterial populations in natural ecosystems. Phages invade the human body, just as they do other natural environments, to such an extent that they are the most numerous group in the human virome. This was only revealed in recent metagenomic studies, despite the fact that the presence of phages in the human body was reported decades ago. The influence of the presence of phages in humans has yet to be evaluated; but as in marine environments, a clear role in the regulation of bacterial populations could be envisaged, that might have an impact on human health. Moreover, phages are excellent vehicles of genetic transfer, and they contribute to the evolution of bacterial cells in the human body by spreading and acquiring DNA horizontally. The abundance of phages in the human body does not pass unnoticed and the immune system reacts to them, although it is not clear to what extent. Finally, the presence of phages in human samples, which most of the time is not considered, can influence and bias microbiological and molecular results; and, in view of the evidences, some studies suggest that more attention needs to be paid to their interference.

Phage lytic enzymes: a history.

Science.gov (United States)

Trudil, David

2015-02-01

There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of 'bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, these lytic enzymes have been shown to efficiently lyse Gram-positive bacteria without affecting normal flora and non-related bacteria. Recent studies have suggested approaches for lysing Gram-negative bacteria as well (Briersa Y, et al., 2014). These enzymes include: phage-lysozyme, endolysin, lysozyme, lysin, phage lysin, phage lytic enzymes, phageassociated enzymes, enzybiotics, muralysin, muramidase, virolysin and designations such as Ply, PAE and others. Bacteriophages are viruses that kill bacteria, do not contribute to antimicrobial resistance, are easy to develop, inexpensive to manufacture and safe for humans, animals and the environment. The current focus on lytic enzymes has been on their use as anti-infectives in humans and more recently in agricultural research models. The initial translational application of lytic enzymes, however, was not associated with treating or preventing a specific disease but rather as an extraction method to be incorporated in a rapid bacterial detection assay (Bernstein D, 1997).The current review traces the translational history of phage lytic enzymes-from their initial discovery in 1986 for the rapid detection of group A streptococcus in clinical specimens to evolving applications in the detection and prevention of disease in humans and in agriculture.

Tales of diversity: Genomic and morphological characteristics of forty-six Arthrobacter phages.

Directory of Open Access Journals (Sweden)

Karen K Klyczek

Full Text Available The vast bacteriophage population harbors an immense reservoir of genetic information. Almost 2000 phage genomes have been sequenced from phages infecting hosts in the phylum Actinobacteria, and analysis of these genomes reveals substantial diversity, pervasive mosaicism, and novel mechanisms for phage replication and lysogeny. Here, we describe the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single Arthrobacter sp. strain. These phages include representatives of all three virion morphologies, and Jasmine is the first sequenced podovirus of an actinobacterial host. The phages also span considerable sequence diversity, and can be grouped into 10 clusters according to their nucleotide diversity, and two singletons each with no close relatives. However, the clusters/singletons appear to be genomically well separated from each other, and relatively few genes are shared between clusters. Genome size varies from among the smallest of siphoviral phages (15,319 bp to over 70 kbp, and G+C contents range from 45-68%, compared to 63.4% for the host genome. Although temperate phages are common among other actinobacterial hosts, these Arthrobacter phages are primarily lytic, and only the singleton Galaxy is likely temperate.

Tales of diversity: Genomic and morphological characteristics of forty-six Arthrobacter phages.

Science.gov (United States)

Klyczek, Karen K; Bonilla, J Alfred; Jacobs-Sera, Deborah; Adair, Tamarah L; Afram, Patricia; Allen, Katherine G; Archambault, Megan L; Aziz, Rahat M; Bagnasco, Filippa G; Ball, Sarah L; Barrett, Natalie A; Benjamin, Robert C; Blasi, Christopher J; Borst, Katherine; Braun, Mary A; Broomell, Haley; Brown, Conner B; Brynell, Zachary S; Bue, Ashley B; Burke, Sydney O; Casazza, William; Cautela, Julia A; Chen, Kevin; Chimalakonda, Nitish S; Chudoff, Dylan; Connor, Jade A; Cross, Trevor S; Curtis, Kyra N; Dahlke, Jessica A; Deaton, Bethany M; Degroote, Sarah J; DeNigris, Danielle M; DeRuff, Katherine C; Dolan, Milan; Dunbar, David; Egan, Marisa S; Evans, Daniel R; Fahnestock, Abby K; Farooq, Amal; Finn, Garrett; Fratus, Christopher R; Gaffney, Bobby L; Garlena, Rebecca A; Garrigan, Kelly E; Gibbon, Bryan C; Goedde, Michael A; Guerrero Bustamante, Carlos A; Harrison, Melinda; Hartwell, Megan C; Heckman, Emily L; Huang, Jennifer; Hughes, Lee E; Hyduchak, Kathryn M; Jacob, Aswathi E; Kaku, Machika; Karstens, Allen W; Kenna, Margaret A; Khetarpal, Susheel; King, Rodney A; Kobokovich, Amanda L; Kolev, Hannah; Konde, Sai A; Kriese, Elizabeth; Lamey, Morgan E; Lantz, Carter N; Lapin, Jonathan S; Lawson, Temiloluwa O; Lee, In Young; Lee, Scott M; Lee-Soety, Julia Y; Lehmann, Emily M; London, Shawn C; Lopez, A Javier; Lynch, Kelly C; Mageeney, Catherine M; Martynyuk, Tetyana; Mathew, Kevin J; Mavrich, Travis N; McDaniel, Christopher M; McDonald, Hannah; McManus, C Joel; Medrano, Jessica E; Mele, Francis E; Menninger, Jennifer E; Miller, Sierra N; Minick, Josephine E; Nabua, Courtney T; Napoli, Caroline K; Nkangabwa, Martha; Oates, Elizabeth A; Ott, Cassandra T; Pellerino, Sarah K; Pinamont, William J; Pirnie, Ross T; Pizzorno, Marie C; Plautz, Emilee J; Pope, Welkin H; Pruett, Katelyn M; Rickstrew, Gabbi; Rimple, Patrick A; Rinehart, Claire A; Robinson, Kayla M; Rose, Victoria A; Russell, Daniel A; Schick, Amelia M; Schlossman, Julia; Schneider, Victoria M; Sells, Chloe A; Sieker, Jeremy W; Silva, Morgan P; Silvi, Marissa M; Simon, Stephanie E; Staples, Amanda K; Steed, Isabelle L; Stowe, Emily L; Stueven, Noah A; Swartz, Porter T; Sweet, Emma A; Sweetman, Abigail T; Tender, Corrina; Terry, Katrina; Thomas, Chrystal; Thomas, Daniel S; Thompson, Allison R; Vanderveen, Lorianna; Varma, Rohan; Vaught, Hannah L; Vo, Quynh D; Vonberg, Zachary T; Ware, Vassie C; Warrad, Yasmene M; Wathen, Kaitlyn E; Weinstein, Jonathan L; Wyper, Jacqueline F; Yankauskas, Jakob R; Zhang, Christine; Hatfull, Graham F

2017-01-01

The vast bacteriophage population harbors an immense reservoir of genetic information. Almost 2000 phage genomes have been sequenced from phages infecting hosts in the phylum Actinobacteria, and analysis of these genomes reveals substantial diversity, pervasive mosaicism, and novel mechanisms for phage replication and lysogeny. Here, we describe the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single Arthrobacter sp. strain. These phages include representatives of all three virion morphologies, and Jasmine is the first sequenced podovirus of an actinobacterial host. The phages also span considerable sequence diversity, and can be grouped into 10 clusters according to their nucleotide diversity, and two singletons each with no close relatives. However, the clusters/singletons appear to be genomically well separated from each other, and relatively few genes are shared between clusters. Genome size varies from among the smallest of siphoviral phages (15,319 bp) to over 70 kbp, and G+C contents range from 45-68%, compared to 63.4% for the host genome. Although temperate phages are common among other actinobacterial hosts, these Arthrobacter phages are primarily lytic, and only the singleton Galaxy is likely temperate.

Relation between parvovirus B19 infection and fetal mortality and spontaneous abortion.

Science.gov (United States)

Shabani, Zahra; Esghaei, Maryam; Keyvani, Hossein; Shabani, Fateme; Sarmadi, Fateme; Mollaie, Hamidreza; Monavari, Seyed Hamidreza

2015-01-01

Infection with parvovirus B19 may cause fetal losses including spontaneous abortion, intrauterine fetal death and non-immune hydrops fetalis. The aim of this study is to determine the frequency of parvovirus B19 in formalin fixed placental tissues in lost fetuses using real-time PCR method. In this cross-sectional study, 100 formalin fixed placental tissues with unknown cause of fetal death were determined using real-time PCR method after DNA extraction. Six out of 100 cases (6%) were positive for parvovirus B19 using real-time PCR. Gestational age of all positive cases was less than 20 weeks with a mean of 12.3 weeks. Three cases have a history of abortion and all of positive cases were collected in spring. Mean age of positive cases were 28 years. Parvovirus B19 during pregnancy can infect red precursor cells and induces apoptosis or lyses these cells that resulting in anemia and congestive heart failure leading to fetal death. Management of parvovirus B19 infection in pregnant women is important because immediate diagnosis and transfusion in hydropsic fetuses can decrease the risk of fetal death.

Molecular Characterization of Three Lactobacillus delbrueckii subsp. bulgaricus Phages

OpenAIRE

Casey, Eoghan; Mahony, Jennifer; O'Connell-Motherway, Mary; Bottacini, Francesca; Cornelissen, Anneleen; Neve, Horst; Heller, Knut J.; Noben, Jean-Paul; Dal Bello, Fabio; van Sinderen, Douwe

2014-01-01

In this study, three phages infecting Lactobacillus delbrueckii subsp. bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for ...

Hyperthermostable binding molecules on phage: Assay components for point-of-care diagnostics for active tuberculosis infection.

Science.gov (United States)

Zhao, Ning; Spencer, John; Schmitt, Margaret A; Fisk, John D

2017-03-15

Tuberculosis is the leading cause of death from infectious disease worldwide. The low sensitivity, extended processing time, and high expense of current diagnostics are major challenges to the detection and treatment of tuberculosis. Mycobacterium tuberculosis ornithine transcarbamylase (Mtb OTC, Rv1656) has been identified in the urine of patients with active TB infection and is a promising target for point-of-care diagnostics. Specific binding proteins with low nanomolar affinities for Mtb OTC were selected from a phage display library built upon a hyperthermostable Sso7d scaffold. Phage particles displaying Sso7d variants were utilized to generate a sandwich ELISA-based assay for Mtb OTC. The assay response is linear between 2 ng/mL and 125 ng/mL recombinant Mtb OTC and has a limit of detection of 400 pg/mL recombinant Mtb OTC. The assay employing a phage-based detection reagent is comparable to commercially-available antibody-based biosensors. Importantly, the assay maintains functionality at both neutral and basic pH in presence of salt and urea over the range of concentrations typical for human urine. Phage-based diagnostic systems may feature improved physical stability and cost of production relative to traditional antibody-based reagents, without sacrificing specificity and sensitivity. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of Bacteriophages on the Growth of Flavobacterium psychrophilum and Development of Phage-Resistant Strains

DEFF Research Database (Denmark)

Christiansen, Rói Hammershaimb; Madsen, Lone; Dalsgaard, Inger

2016-01-01

The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage concentr......The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage...... concentration (MOI = 0.3–4) was crucial for efficient viral lysis, resulting in a 104–105-fold reduction of phage-sensitive cells (both single phages and phage cocktails), which was maintained throughout the incubation (>10 days). Following cell lysis, regrowth of phage-resistant strains was examined...... and resistant strains were isolated for further characterization. The application of a mathematical model allowed simulation of phage-host interactions and resistance development, confirming indications from strain isolations that phage-sensitive strains dominated the regrowing population (>99.8 %) at low MOI...

Study of the phage production efficiency in the bacteria lysis processes

International Nuclear Information System (INIS)

Vidania Munoz, R. de; Garces, F.; Davila, C. A.

1979-01-01

In this work we present a search for the best production conditions of λvir andλ clear phages In E coli K12 and E coli C 6 00 infected cells respectively. By keeping fixed some parameters of the process as the bacterial and phage generation times and (he bacterial burst side, we have finder that the lysis yield is strongly dependent on the multiplicity and in a lesser degree on the infection time. It appears from the experimental results that other variables are important, as infection efficiency and approach time from phages to bacteria. We will try to describe the lysis phenomenon by a numerical model on the bases of the se experimental results. (Author) 11 refs

Phage Therapy -- Everything Old Is New again

Directory of Open Access Journals (Sweden)

Andrew M Kropinski

2006-01-01

Full Text Available The study of bacterial viruses (bacteriophages or phages proved pivotal in the nascence of the disciplines of molecular biology and microbial genetics, providing important information on the central processes of the bacterial cell (DNA replication, transcription and translation and on how DNA can be transferred from one cell to another. As a result of the pioneering genetics studies and modern genomics, it is now known that phages have contributed to the evolution of the microbial cell and to its pathogenic potential. Because of their ability to transmit genes, phages have been exploited to develop cloning vector systems. They also provide a plethora of enzymes for the modern molecular biologist. Until the introduction of antibiotics, phages were used to treat bacterial infections (with variable success. Western science is now having to re-evaluate the application of phage therapy -- a therapeutic modality that never went out of vogue in Eastern Europe -- because of the emergence of an alarming number of antibiotic-resistant bacteria. The present article introduces the reader to phage biology, and the benefits and pitfalls of phage therapy in humans and animals.

Molecular Characterization of Three Lactobacillus delbrueckii subsp. bulgaricus Phages

Science.gov (United States)

Casey, Eoghan; Mahony, Jennifer; O'Connell-Motherway, Mary; Bottacini, Francesca; Cornelissen, Anneleen; Neve, Horst; Heller, Knut J.; Noben, Jean-Paul; Dal Bello, Fabio

2014-01-01

In this study, three phages infecting Lactobacillus delbrueckii subsp. bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for one phage, transcriptional analysis by Northern hybridization, reverse transcription-PCR, and primer extension. The three obtained phage genomes display high levels of sequence identity to each other and to genomes of the so-called group b L. delbrueckii phages c5, LL-Ku, and phiLdb, where some of the observed differences are believed to be responsible for host range variations. PMID:25002431

Phage Genetic Engineering Using CRISPR–Cas Systems

Directory of Open Access Journals (Sweden)

Asma Hatoum-Aslan

2018-06-01

Full Text Available Since their discovery over a decade ago, the class of prokaryotic immune systems known as CRISPR–Cas have afforded a suite of genetic tools that have revolutionized research in model organisms spanning all domains of life. CRISPR-mediated tools have also emerged for the natural targets of CRISPR–Cas immunity, the viruses that specifically infect bacteria, or phages. Despite their status as the most abundant biological entities on the planet, the majority of phage genes have unassigned functions. This reality underscores the need for robust genetic tools to study them. Recent reports have demonstrated that CRISPR–Cas systems, specifically the three major types (I, II, and III, can be harnessed to genetically engineer phages that infect diverse hosts. Here, the mechanisms of each of these systems, specific strategies used, and phage editing efficacies will be reviewed. Due to the relatively wide distribution of CRISPR–Cas systems across bacteria and archaea, it is anticipated that these immune systems will provide generally applicable tools that will advance the mechanistic understanding of prokaryotic viruses and accelerate the development of novel technologies based on these ubiquitous organisms.

The genome of the Erwinia amylovora phage PhiEaH1 reveals greater diversity and broadens the applicability of phages for the treatment of fire blight.

Science.gov (United States)

Meczker, Katalin; Dömötör, Dóra; Vass, János; Rákhely, Gábor; Schneider, György; Kovács, Tamás

2014-01-01

The enterobacterium Erwinia amylovora is the causal agent of fire blight. This study presents the analysis of the complete genome of phage PhiEaH1, isolated from the soil surrounding an E. amylovora-infected apple tree in Hungary. Its genome is 218 kb in size, containing 244 ORFs. PhiEaH1 is the second E. amylovora infecting phage from the Siphoviridae family whose complete genome sequence was determined. Beside PhiEaH2, PhiEaH1 is the other active component of Erwiphage, the first bacteriophage-based pesticide on the market against E. amylovora. Comparative genome analysis in this study has revealed that PhiEaH1 not only differs from the 10 formerly sequenced E. amylovora bacteriophages belonging to other phage families, but also from PhiEaH2. Sequencing of more Siphoviridae phage genomes might reveal further diversity, providing opportunities for the development of even more effective biological control agents, phage cocktails against Erwinia fire blight disease of commercial fruit crops.

Complete Genome Sequences of 44 Arthrobacter Phages.

Science.gov (United States)

Klyczek, Karen K; Jacobs-Sera, Deborah; Adair, Tamarah L; Adams, Sandra D; Ball, Sarah L; Benjamin, Robert C; Bonilla, J Alfred; Breitenberger, Caroline A; Daniels, Charles J; Gaffney, Bobby L; Harrison, Melinda; Hughes, Lee E; King, Rodney A; Krukonis, Gregory P; Lopez, A Javier; Monsen-Collar, Kirsten; Pizzorno, Marie C; Rinehart, Claire A; Staples, Amanda K; Stowe, Emily L; Garlena, Rebecca A; Russell, Daniel A; Cresawn, Steven G; Pope, Welkin H; Hatfull, Graham F

2018-02-01

We report here the complete genome sequences of 44 phages infecting Arthrobacter sp. strain ATCC 21022. These phages have double-stranded DNA genomes with sizes ranging from 15,680 to 70,707 bp and G+C contents from 45.1% to 68.5%. All three tail types (belonging to the families Siphoviridae , Myoviridae , and Podoviridae ) are represented. Copyright © 2018 Klyczek et al.

Ciprofloxacin and Trimethoprim Cause Phage Induction and Virulence Modulation in Staphylococcus aureus

Science.gov (United States)

Goerke, Christiane; Köller, Johanna; Wolz, Christiane

2006-01-01

In Staphylococcus aureus strains of human origin, phages which integrate into the chromosomal gene coding for β-hemolysin (hlb) are widely distributed. Most of them encode accessory virulence determinants such as staphylokinase (sak) or enterotoxins. Here, we analyzed the effects of ciprofloxacin and trimethoprim on phage induction and expression of phage-encoded virulence factors by using isolates from patients with cystic fibrosis for which the induction of hlb-converting phages was demonstrated in vivo (C. Goerke, S. Matias y Papenberg, S. Dasbach, K. Dietz, R. Ziebach, B. C. Kahl, and C. Wolz, J. Infect. Dis. 189:724-734, 2004) as well as a φ13 lysogen of phage-cured strain 8325-4. Treatment of lysogens with subinhibitory concentrations of either antibiotic resulted in (i) delysogenization of strains resembling the isolates picked up after chronic lung infection and (ii) replication of phages in the bacterial host in a dose-dependent manner. Ciprofloxacin treatment resulted in enhanced recA transcription, indicating involvement of the SOS response in phage mobilization. Induction of φ13 was linked to elevated expression of the phage-encoded virulence gene sak, chiefly due to the activation of latent phage promoters. In summary, we could show the induction of hlb-converting phages and a subsequent virulence modulation of the host bacterium by ciprofloxacin and trimethoprim. PMID:16377683

Staphylococcus aureus phage types and their correlation to antibiotic resistance

Directory of Open Access Journals (Sweden)

Mehndiratta P

2010-10-01

Full Text Available Context: Staphylococcus aureus is one of the most devastating human pathogen. The organism has a differential ability to spread and cause outbreak of infections. Characterization of these strains is important to control the spread of infection in the hospitals as well as in the community. Aim: To identify the currently existing phage groups of Staphylococcus aureus, their prevalence and resistance to antibiotics. Materials and Methods: Study was undertaken on 252 Staphylococcus aureus strains isolated from clinical samples. Strains were phage typed and their resistance to antibiotics was determined following standard microbiological procedures. Statistical Analysis: Chi square test was used to compare the antibiotic susceptibility between methicillin resistant Staph. aureus (MRSA and methicillin sensitive S. aureus (MSSA strains. Results: Prevalence of MRSA and MSSA strains was found to be 29.36% and 70.65% respectively. Of these 17.56% of MRSA and 40.44% of MSSA strains were community acquired. All the MSSA strains belonging to phage type 81 from the community were sensitive to all the antibiotics tested including clindamycin and were resistant to penicillin. Forty five percent strains of phage group III and 39% of non-typable MRSA strains from the hospital were resistant to multiple antibiotics. Conclusion: The study revealed that predominant phage group amongst MRSA strains was phage group III and amongst MSSA from the community was phage group NA (phage type 81. MSSA strains isolated from the community differed significantly from hospital strains in their phage type and antibiotic susceptibility. A good correlation was observed between community acquired strains of phage type 81 and sensitivity to gentamycin and clindamycin.

Restriction of phage T4 internal protein I mutants by a strain of Escherichia coli

International Nuclear Information System (INIS)

Black, L.W.; Abremski, K.

1974-01-01

Phage T4 internal protein I(IPI), a small (ca, 10,000 MW), basic protein injected into the host with the phage DNA, is not required for infection of most hosts, but mutants defective in IPI are restricted by at least one naturally occurring strain of Escherichia coli, CT 596 (CT). Phages lacking IPI (IPI - ) appear to inject their DNA and bind it to the membrane of CT cells as well as wild-type phage T4 does, but shutoff of host protein synthesis, initiation of T4 protein synthesis, and cell killing are abnormal in the IPI - mutant infected CT host. The injection of IPI appears to be important in allowing T4 DNA to carry out early steps involved in takeover of this host. Restriction of IPI - phage growth by CT cells appears to be due, at least in part, to a defective prophage it harbors which renders the host resistant to successful infection by phage T4 which lack IPI or rII functions. Bacteria cured of this prophage can be infected by mutants defective in these functions. The resistance of CT cells to other coliphages, and the question of T-even phage internal protein diversity are discussed. (U.S.)

Two Novel Myoviruses from the North of Iraq Reveal Insights into Clostridium difficile Phage Diversity and Biology

Directory of Open Access Journals (Sweden)

Srwa J. Rashid

2016-11-01

Full Text Available Bacteriophages (phages are increasingly being explored as therapeutic agents to combat bacterial diseases, including Clostridium difficile infections. Therapeutic phages need to be able to efficiently target and kill a wide range of clinically relevant strains. While many phage groups have yet to be investigated in detail, those with new and useful properties can potentially be identified when phages from newly studied geographies are characterised. Here, we report the isolation of C. difficile phages from soil samples from the north of Iraq. Two myoviruses, CDKM15 and CDKM9, were selected for detailed sequence analysis on the basis of their broad and potentially useful host range. CDKM9 infects 25/80 strains from 12/20 C. difficile ribotypes, and CDKM15 infects 20/80 strains from 9/20 ribotypes. Both phages can infect the clinically relevant ribotypes R027 and R001. Phylogenetic analysis based on whole genome sequencing revealed that the phages are genetically distinct from each other but closely related to other long-tailed myoviruses. A comparative genomic analysis revealed key differences in the genes predicted to encode for proteins involved in bacterial infection. Notably, CDKM15 carries a clustered regularly interspaced short palindromic repeat (CRISPR array with spacers that are homologous to sequences in the CDKM9 genome and of phages from diverse localities. The findings presented suggest a possible shared evolutionary past for these phages and provides evidence of their widespread dispersal.

Molecular characterization of three Lactobacillus delbrueckii subsp. bulgaricus phages.

Science.gov (United States)

Casey, Eoghan; Mahony, Jennifer; O'Connell-Motherway, Mary; Bottacini, Francesca; Cornelissen, Anneleen; Neve, Horst; Heller, Knut J; Noben, Jean-Paul; Dal Bello, Fabio; van Sinderen, Douwe

2014-09-01

In this study, three phages infecting Lactobacillus delbrueckii subsp. bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for one phage, transcriptional analysis by Northern hybridization, reverse transcription-PCR, and primer extension. The three obtained phage genomes display high levels of sequence identity to each other and to genomes of the so-called group b L. delbrueckii phages c5, LL-Ku, and phiLdb, where some of the observed differences are believed to be responsible for host range variations. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Interaction of the phage-xanthomonas campestris (Pammel) Dowson at the eletronic microscopy level, Virazole effect and radioautographic study of the phage action on the host

International Nuclear Information System (INIS)

Sittolin, I.M.

1982-04-01

A bacteriophage from the cabbage tissue infected with Xanthomonas campestris is described. The infection process is studied through a negative staining technique (PTA) and ultrathin section. The effect of Virazole, an antivirus agent, is tested. Radioautography showed that the phage presented a reasonable domain on the bacterial host genome since the beginning of the treatment. Sorological reactions indicated the induction of specific antibodies for the phage. (M.A.C.) [pt

Coevolution of CRISPR bacteria and phage in 2 dimensions

Science.gov (United States)

Han, Pu; Deem, Michael

2014-03-01

CRISPR (cluster regularly interspaced short palindromic repeats) is a newly discovered adaptive, heritable immune system of prokaryotes. It can prevent infection of prokaryotes by phage. Most bacteria and almost all archae have CRISPR. The CRISPR system incorporates short nucleotide sequences from viruses. These incorporated sequences provide a historical record of the host and predator coevolution. We simulate the coevolution of bacteria and phage in 2 dimensions. Each phage has multiple proto-spacers that the bacteria can incorporate. Each bacterium can store multiple spacers in its CRISPR. Phages can escape recognition by the CRISPR system via point mutation or recombination. We will discuss the different evolutionary consequences of point mutation or recombination on the coevolution of bacteria and phage. We will also discuss an intriguing ``dynamic phase transition'' in the number of phage as a function of time and mutation rate. We will show that due to the arm race between phages and bacteria, the frequency of spacers and proto-spacers in a population can oscillate quite rapidly.

Diagnostic studies of abortion in Danish dairy herds

DEFF Research Database (Denmark)

Agerholm, J.S.; Willadsen, C. M.; Nielsen, Thomas Krogh

1997-01-01

Diagnostic findings in 218 aborted bovine foetuses are reported. The materials were examined in a matched case-control study of 69 Danish dairy herds with a sudden increase in the number of abortions and a corresponding 69 control herds. Foetuses aborted during the subsequent 6-month period were...... examined to identify the cause of abortion if possible. A total of 186 specimens were submitted from case herds and 32 from control herds. A likely cause of abortion was diagnosed in 73 foetuses. The most common cause was bovine viral diarrhoea virus (BVDV: 13%) followed by Neospora caninum infection (10......%), mycosis (5%) and Bacillus licheniformis infection (4%). Foetal and/or placental lesions were found in a further 27 cases. Only BVDV infection and neosporosis were diagnosed in more than one foetus per herd and only protozoal associated abortions occurred significantly more frequently in the case, rather...

Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

International Nuclear Information System (INIS)

Mahony, Jennifer; Ainsworth, Stuart; Stockdale, Stephen; Sinderen, Douwe van

2012-01-01

Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

Energy Technology Data Exchange (ETDEWEB)

Mahony, Jennifer, E-mail: j.mahony@ucc.ie [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Ainsworth, Stuart; Stockdale, Stephen [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Sinderen, Douwe van, E-mail: d.vansinderen@ucc.ie [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Western Road, Cork (Ireland)

2012-12-20

Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

Yersinia enterocolitica-Specific Infection by Bacteriophages TG1 and ϕR1-RT Is Dependent on Temperature-Regulated Expression of the Phage Host Receptor OmpF.

Science.gov (United States)

Leon-Velarde, Carlos G; Happonen, Lotta; Pajunen, Maria; Leskinen, Katarzyna; Kropinski, Andrew M; Mattinen, Laura; Rajtor, Monika; Zur, Joanna; Smith, Darren; Chen, Shu; Nawaz, Ayesha; Johnson, Roger P; Odumeru, Joseph A; Griffiths, Mansel W; Skurnik, Mikael

2016-09-01

Bacteriophages present huge potential both as a resource for developing novel tools for bacterial diagnostics and for use in phage therapy. This potential is also valid for bacteriophages specific for Yersinia enterocolitica To increase our knowledge of Y. enterocolitica-specific phages, we characterized two novel yersiniophages. The genomes of the bacteriophages vB_YenM_TG1 (TG1) and vB_YenM_ϕR1-RT (ϕR1-RT), isolated from pig manure in Canada and from sewage in Finland, consist of linear double-stranded DNA of 162,101 and 168,809 bp, respectively. Their genomes comprise 262 putative coding sequences and 4 tRNA genes and share 91% overall nucleotide identity. Based on phylogenetic analyses of their whole-genome sequences and large terminase subunit protein sequences, a genus named Tg1virus within the family Myoviridae is proposed, with TG1 and ϕR1-RT (R1RT in the ICTV database) as member species. These bacteriophages exhibit a host range restricted to Y. enterocolitica and display lytic activity against the epidemiologically significant serotypes O:3, O:5,27, and O:9 at and below 25°C. Adsorption analyses of lipopolysaccharide (LPS) and OmpF mutants demonstrate that these phages use both the LPS inner core heptosyl residues and the outer membrane protein OmpF as phage receptors. Based on RNA sequencing and quantitative proteomics, we also demonstrate that temperature-dependent infection is due to strong repression of OmpF at 37°C. In addition, ϕR1-RT was shown to be able to enter into a pseudolysogenic state. Together, this work provides further insight into phage-host cell interactions by highlighting the importance of understanding underlying factors which may affect the abundance of phage host receptors on the cell surface. Only a small number of bacteriophages infecting Y. enterocolitica, the predominant causative agent of yersiniosis, have been previously described. Here, two newly isolated Y. enterocolitica phages were studied in detail, with the aim of

Epifluorescence and atomic force microscopy: Two innovative applications for studying phage-host interactions in Lactobacillus helveticus.

Science.gov (United States)

Zago, Miriam; Scaltriti, Erika; Fornasari, Maria Emanuela; Rivetti, Claudio; Grolli, Stefano; Giraffa, Giorgio; Ramoni, Roberto; Carminati, Domenico

2012-01-01

Bacteriophages attacking lactic acid bacteria (LAB) still represent a crucial problem in industrial dairy fermentations. The consequences of a phage infection against LAB can lead to fermentation delay, alteration of the product quality and, in most severe cases, the product loss. Phage particles enumeration and phage-host interactions are normally evaluated by conventional plaque count assays, but, in many cases, these methods can be unsuccessful. Bacteriophages of Lactobacillus helveticus, a LAB species widely used as dairy starter or probiotic cultures, are often unable to form lysis plaques, thus impairing their enumeration by plate assay. In this study, we used epifluorescence microscopy to enumerate L. helveticus phage particles from phage-infected cultures and Atomic Force Microscopy (AFM) to visualize both phages and bacteria during the different stages of the lytic cycle. Preliminary, we tested the sensitivity of phage counting by epifluorescence microscopy. To this end, phage particles of ΦAQ113, a lytic phage of L. helveticus isolated from a whey starter culture, were stained by SYBR Green I and enumerated by epifluorescence microscopy. Values obtained by the microscopic method were 10 times higher than plate counts, with a lowest sensitivity limit of ≥6log phage/ml. The interaction of phage ΦAQ113 with its host cell L. helveticus Lh1405 was imaged by AFM after 0, 2 and 5h from phage-host adsorption. The lytic cycle was followed by epifluorescence microscopy counting and the concomitant cell wall changes were visualized by AFM imaging. Our results showed that these two methods can be combined for a reliable phage enumeration and for studying phage and host morphology during infection processes, thus giving a complete overview of phage-host interactions in L. helveticus strains involved in dairy productions. Copyright © 2011 Elsevier B.V. All rights reserved.

Novel type of specialized transduction for CTX phi or its satellite phage RS1 mediated by filamentous phage VGJ phi in Vibrio cholerae.

Science.gov (United States)

Campos, Javier; Martínez, Eriel; Marrero, Karen; Silva, Yussuan; Rodríguez, Boris L; Suzarte, Edith; Ledón, Talena; Fando, Rafael

2003-12-01

The main virulence factor of Vibrio cholerae, the cholera toxin, is encoded by the ctxAB operon, which is contained in the genome of the lysogenic filamentous phage CTX phi. This phage transmits ctxAB genes between V. cholerae bacterial populations that express toxin-coregulated pilus (TCP), the CTX phi receptor. In investigating new forms of ctxAB transmission, we found that V. cholerae filamentous phage VGJ phi, which uses the mannose-sensitive hemagglutinin (MSHA) pilus as a receptor, transmits CTX phi or its satellite phage RS1 by an efficient and highly specific TCP-independent mechanism. This is a novel type of specialized transduction consisting in the site-specific cointegration of VGJ phi and CTX phi (or RS1) replicative forms to produce a single hybrid molecule, which generates a single-stranded DNA hybrid genome that is packaged into hybrid viral particles designated HybP phi (for the VGJ phi/CTX phi hybrid) and HybRS phi (for the VGJ phi/RS1 hybrid). The hybrid phages replicate by using the VGJ phi replicating functions and use the VGJ phi capsid, retaining the ability to infect via MSHA. The hybrid phages infect most tested strains more efficiently than CTX phi, even under in vitro optimal conditions for TCP expression. Infection and lysogenization with HybP phi revert the V. cholerae live attenuated vaccine strain 1333 to virulence. Our results reinforce that TCP is not indispensable for the acquisition of CTX phi. Thus, we discuss an alternative to the current accepted evolutionary model for the emergence of new toxigenic strains of V. cholerae and the importance of our findings for the development of an environmentally safer live attenuated cholera vaccine.

Basic Phage Mathematics.

Science.gov (United States)

Abedon, Stephen T; Katsaounis, Tena I

2018-01-01

Basic mathematical descriptions are useful in phage ecology, applied phage ecology such as in the course of phage therapy, and also toward keeping track of expected phage-bacterial interactions as seen during laboratory manipulation of phages. The most basic mathematical descriptor of phages is their titer, that is, their concentration within stocks, experimental vessels, or other environments. Various phenomena can serve to modify phage titers, and indeed phage titers can vary as a function of how they are measured. An important aspect of how changes in titers can occur results from phage interactions with bacteria. These changes tend to vary in degree as a function of bacterial densities within environments, and particularly densities of those bacteria that are susceptible to or at least adsorbable by a given phage type. Using simple mathematical models one can describe phage-bacterial interactions that give rise particularly to phage adsorption events. With elaboration one can consider changes in both phage and bacterial densities as a function of both time and these interactions. In addition, phages along with their impact on bacteria can be considered as spatially constrained processes. In this chapter we consider the simpler of these concepts, providing in particular detailed verbal explanations toward facile mathematical insight. The primary goal is to stimulate a more informed use and manipulation of phages and phage populations within the laboratory as well as toward more effective phage application outside of the laboratory, such as during phage therapy. More generally, numerous issues and approaches to the quantification of phages are considered along with the quantification of individual, ecological, and applied properties of phages.

Phage display peptide libraries: deviations from randomness and correctives

Science.gov (United States)

Ryvkin, Arie; Ashkenazy, Haim; Weiss-Ottolenghi, Yael; Piller, Chen; Pupko, Tal; Gershoni, Jonathan M

2018-01-01

Abstract Peptide-expressing phage display libraries are widely used for the interrogation of antibodies. Affinity selected peptides are then analyzed to discover epitope mimetics, or are subjected to computational algorithms for epitope prediction. A critical assumption for these applications is the random representation of amino acids in the initial naïve peptide library. In a previous study, we implemented next generation sequencing to evaluate a naïve library and discovered severe deviations from randomness in UAG codon over-representation as well as in high G phosphoramidite abundance causing amino acid distribution biases. In this study, we demonstrate that the UAG over-representation can be attributed to the burden imposed on the phage upon the assembly of the recombinant Protein 8 subunits. This was corrected by constructing the libraries using supE44-containing bacteria which suppress the UAG driven abortive termination. We also demonstrate that the overabundance of G stems from variant synthesis-efficiency and can be corrected using compensating oligonucleotide-mixtures calibrated by mass spectroscopy. Construction of libraries implementing these correctives results in markedly improved libraries that display random distribution of amino acids, thus ensuring that enriched peptides obtained in biopanning represent a genuine selection event, a fundamental assumption for phage display applications. PMID:29420788

Understanding the enormous diversity of bacteriophages: the tailed phages that infect the bacterial family Enterobacteriaceae

Science.gov (United States)

Grose, Julianne H.; Casjens, Sherwood R.

2014-01-01

Bacteriophages are the predominant biological entity on the planet. The recent explosion of sequence information has made estimates of their diversity possible. We describe the genomic comparison of 337 fully sequenced tailed phages isolated on 18 genera and 31 species of bacteria in the Enterobacteriaceae. These phages were largely unambiguously grouped into 56 diverse clusters (32 lytic and 24 temperate) that have syntenic similarity over >50% of the genomes within each cluster, but substantially less sequence similarity between clusters. Most clusters naturally break into sets of more closely related subclusters, 78% of which are correlated with their host genera. The largest groups of related phages are superclusters united by genome synteny to lambda (81 phages) and T7 (51 phages). This study forms a robust framework for understanding diversity and evolutionary relationships of existing tailed phages, for relating newly discovered phages and for determining host/phage relationships. PMID:25240328

Evaluation of an ompA-based phage-mediated DNA vaccine against Chlamydia abortus in piglets.

Science.gov (United States)

Ou, Changbo; Tian, Deyu; Ling, Yong; Pan, Qing; He, Qing; Eko, Francis O; He, Cheng

2013-08-01

Chlamydia abortus (C. abortus) is an obligate intracellular pathogen that causes abortion in pigs and poses a zoonotic risk in pregnant women. Although attenuated and inactivated vaccines are available, they do not provide complete protection in animals underlining the need to develop new vaccines. In this study, we tested the hypothesis that intramuscular immunization with an ompA-based phage-mediated DNA chlamydial vaccine candidate will induce significant antigen-specific cellular and humoral immune responses. Thus, groups of piglets (five per group) were immunized intramuscularly with the phage-MOMP vaccine (λ-MOMP) or a commercial live-attenuated vaccine (1B vaccine) or a GFP-expressing phage (λ-GFP) or phosphate buffered saline (PBS) (control) and antigen-specific cell-mediated and humoral immune responses were evaluated. By day 63 post-immunization, the λ-MOMP vaccine elicited significantly higher (Pabortus. Copyright © 2013 Elsevier B.V. All rights reserved.

The use of phage FCL-2 as an alternative to chemotherapy against columnaris disease in aquaculture

Directory of Open Access Journals (Sweden)

Elina eLaanto

2015-08-01

Full Text Available Flavobacterium columnare, the causative agent of columnaris disease in fish, causes millions of dollars of losses in the US channel catfish industry alone, not to mention aquaculture industry worldwide. Novel methods are needed for the control and treatment of bacterial diseases in aquaculture to replace traditionally used chemotherapies. A potential solution could be the use of phages, i.e., bacterial viruses, host-specific and self-enriching particles that can be can easily distributed via water flow. We examined the efficacy of phages to combat columnaris disease. A previously isolated phage, FCL-2, infecting F. columnare, was characterized by sequencing. The 47 142 bp genome of the phage had G + C content of 30.2%, and the closest similarities regarding the structural proteins were found in Cellulophaga phage phiSM. Under controlled experimental conditions, two host fish species, rainbow trout (Oncorhynchus mykiss and zebrafish (Danio rerio, were used to study the success of phage therapy to prevent F. columnare infections. The survival of both fish species was significantly higher in the presence of the phage. Hundred percent of the zebrafish and 50 % of the rainbow trout survived in the phage treatment (survival without phage 0 % and 8.3 %, respectively. Most importantly, the rainbow trout population was rescued from infection by a single addition of the phage into the water in a flow-through fish tank system. Thus, F. columnare could be used as a model system to test the benefits and risks of phage therapy on a larger scale.

Bioinformatic analysis of phage AB3, a phiKMV-like virus infecting Acinetobacter baumannii.

Science.gov (United States)

Zhang, J; Liu, X; Li, X-J

2015-01-16

The phages of Acinetobacter baumannii has drawn increasing attention because of the multi-drug resistance of A. baumanni. The aim of this study was to sequence Acinetobacter baumannii phage AB3 and conduct bioinformatic analysis to lay a foundation for genome remodeling and phage therapy. We isolated and sequenced A. baumannii phage AB3 and attempted to annotate and analyze its genome. The results showed that the genome is a double-stranded DNA with a total length of 31,185 base pairs (bp) and 97 open reading frames greater than 100 bp. The genome includes 28 predicted genes, of which 24 are homologous to phage AB1. The entire coding sequence is located on the negative strand, representing 90.8% of the total length. The G+C mol% was 39.18%, without areas of high G+C content over 200 bp in length. No GC island, tRNA gene, or repeated sequence was identified. Gene lengths were 120-3099 bp, with an average of 1011 bp. Six genes were found to be greater than 2000 bp in length. Genomic alignment and phylogenetic analysis of the RNA polymerase gene showed that similar to phage AB1, phage AB3 is a phiKMV-like virus in the T7 phage family.

Youth often risk unsafe abortions.

Science.gov (United States)

Barnett, B

1993-10-01

The topic of this article is the use of unsafe abortion for unwanted pregnancies among adolescents. The significance of unsafe abortion is identified as a high risk of serious health problems, such as infection, hemorrhage, infertility, and mortality, and as a strain on emergency room services. The World Health Organization estimates that at least 33% of all women seeking hospital care for abortion complications are aged under 20 years. 50 million abortions are estimated to be induced annually, of which 33% are illegal and almost 50% are performed outside the health care system. Complications are identified as occurring due to the procedure itself (perforation of the uterus, cervical lacerations, or hemorrhage) and due to incomplete abortion or introduction of bacteria into the uterus. Long-term complications include an increased risk of ectopic pregnancy, chronic pelvic infection, and infertility. Mortality from unsafe abortion is estimated at 1000/100,000 procedures. Safe abortion mortality is estimated at 0.6/100,000. When infertility results, some cultures ascribe an outcast status or marriages are prevented or prostitution is assured. The risk of complications is considered higher for adolescents. Adolescents tend to delay seeking an abortion, lack knowledge on where to go for a safe procedure, and delay seeking help for complications. Peer advice may be limited or inadequate knowledge. Five studies are cited that illustrate the impact of unsafe abortion on individuals and health care systems. Abortions may be desired due to fear of parental disapproval of the pregnancy, abandonment by the father, financial and emotional responsibilities of child rearing, expulsion from school, or inability to marry if the child is out of wedlock. Medical, legal, and social barriers may prevent women and girls from obtaining safe abortion. Parental permission is sometimes a requirement for safe abortion. Fears of judgmental or callous health personnel may be barriers to

Phage T4 SegB protein is a homing endonuclease required for the preferred inheritance of T4 tRNA gene region occurring in co-infection with a related phage.

Science.gov (United States)

Brok-Volchanskaya, Vera S; Kadyrov, Farid A; Sivogrivov, Dmitry E; Kolosov, Peter M; Sokolov, Andrey S; Shlyapnikov, Michael G; Kryukov, Valentine M; Granovsky, Igor E

2008-04-01

Homing endonucleases initiate nonreciprocal transfer of DNA segments containing their own genes and the flanking sequences by cleaving the recipient DNA. Bacteriophage T4 segB gene, which is located in a cluster of tRNA genes, encodes a protein of unknown function, homologous to homing endonucleases of the GIY-YIG family. We demonstrate that SegB protein is a site-specific endonuclease, which produces mostly 3' 2-nt protruding ends at its DNA cleavage site. Analysis of SegB cleavage sites suggests that SegB recognizes a 27-bp sequence. It contains 11-bp conserved sequence, which corresponds to a conserved motif of tRNA TpsiC stem-loop, whereas the remainder of the recognition site is rather degenerate. T4-related phages T2L, RB1 and RB3 contain tRNA gene regions that are homologous to that of phage T4 but lack segB gene and several tRNA genes. In co-infections of phages T4 and T2L, segB gene is inherited with nearly 100% of efficiency. The preferred inheritance depends absolutely on the segB gene integrity and is accompanied by the loss of the T2L tRNA gene region markers. We suggest that SegB is a homing endonuclease that functions to ensure spreading of its own gene and the surrounding tRNA genes among T4-related phages.

Q-feber som årsag til spontan abort

DEFF Research Database (Denmark)

Nielsen, Stine Yde; Mølbak, Kåre; Hjøllund, Niels Henrik

2011-01-01

Q-fever is a zoonotic infection. Pregnant women constitute a specific risk group as the infection may cause spontaneous abortion, intrauterine death, growth retardation, oligohydramnios and premature birth. A 39 year-old veterinarian had a spontaneous abortion in pregnancy week seven. During the ...

Effect of Antiviral Agents in Equine Abortion Virus-Infected Hamsters1

Science.gov (United States)

Lieberman, Melvin; Pascale, Andrea; Schafer, Thomas W.; Came, Paul E.

1972-01-01

Equine abortion virus, a member of the herpesvirus group, produces a lethal infection in hamsters. With this system, the protective effect of certain inhibitors of deoxyribonucleic acid viruses, inducers of interferon and exogenous interferon, was evaluated. Of the various agents studied, 9-β-d-arabinofuranosyladenine markedly suppressed mortality, and 5-iodo-2′-deoxyuridine, distamycin A, and N-ethylisatin β-thiosemicarbazone were inactive. Of the inducers tested, statolon, ultraviolet-irradiated Newcastle disease virus, and polyriboinosinic:polyribocytidylic acid (poly I:C) were protective, and endotoxin, polyacrylic acid, and polymethacrylic acid did not protect. Administration of exogenous interferon did not afford protection. Statolon and ultraviolet-irradiated Newcastle disease virus induced circulating interferon in hamsters, whereas poly I:C, endotoxin, and polyacrylic acid did not produce interferon. Because of the severity of the disease produced in hamsters by equine abortion virus, lack of protective activity by an agent in this system should not preclude possible efficacy against other members of the herpesvirus group. PMID:4376907

Hybrid Nanomaterial Complexes for Advanced Phage-guided Gene Delivery

Directory of Open Access Journals (Sweden)

Teerapong Yata

2014-01-01

Full Text Available Developing nanomaterials that are effective, safe, and selective for gene transfer applications is challenging. Bacteriophages (phage, viruses that infect bacteria only, have shown promise for targeted gene transfer applications. Unfortunately, limited progress has been achieved in improving their potential to overcome mammalian cellular barriers. We hypothesized that chemical modification of the bacteriophage capsid could be applied to improve targeted gene delivery by phage vectors into mammalian cells. Here, we introduce a novel hybrid system consisting of two classes of nanomaterial systems, cationic polymers and M13 bacteriophage virus particles genetically engineered to display a tumor-targeting ligand and carry a transgene cassette. We demonstrate that the phage complex with cationic polymers generates positively charged phage and large aggregates that show enhanced cell surface attachment, buffering capacity, and improved transgene expression while retaining cell type specificity. Moreover, phage/polymer complexes carrying a therapeutic gene achieve greater cancer cell killing than phage alone. This new class of hybrid nanomaterial platform can advance targeted gene delivery applications by bacteriophage.

Comparison of abortion and infection after experimental challenge of pregnant bison and cattle with Brucella abortus strain 2308

Science.gov (United States)

A comparative study was conducted using data from naive bison (n=45) and cattle (n=46) from 8 and 6 studies, respectively, in which a standardized Brucella abortus strain 2308 experimental challenge was administered. The incidence of abortion, fetal infection, uterine or mammary infection, or infec...

Early RNA of adenovirus type 3 in permissive and abortive infections.

OpenAIRE

Groff, D E; Daniell, E

1981-01-01

Early adenovirus type 3 cytoplasmic polyadenylated RNAs from HeLa and BHK-21 cells were detected and mapped on the viral genome by gel blotting and hybridization techniques. The sizes and locations of the 16 adenovirus type 3 RNAs were identical in the two cell types, although relative molarities of the various RNA species differed. Each of the early adenovirus type 3 RNAs was associated with polysomes in both cell types, suggesting that the abortive infection of hamster cells does not result...

Genome of a SAR116 bacteriophage shows the prevalence of this phage type in the oceans.

Science.gov (United States)

Kang, Ilnam; Oh, Hyun-Myung; Kang, Dongmin; Cho, Jang-Cheon

2013-07-23

The abundance, genetic diversity, and crucial ecological and evolutionary roles of marine phages have prompted a large number of metagenomic studies. However, obtaining a thorough understanding of marine phages has been hampered by the low number of phage isolates infecting major bacterial groups other than cyanophages and pelagiphages. Therefore, there is an urgent requirement for the isolation of phages that infect abundant marine bacterial groups. In this study, we isolated and characterized HMO-2011, a phage infecting a bacterium of the SAR116 clade, one of the most abundant marine bacterial lineages. HMO-2011, which infects "Candidatus Puniceispirillum marinum" strain IMCC1322, has an ~55-kb dsDNA genome that harbors many genes with novel features rarely found in cultured organisms, including genes encoding a DNA polymerase with a partial DnaJ central domain and an atypical methanesulfonate monooxygenase. Furthermore, homologs of nearly all HMO-2011 genes were predominantly found in marine metagenomes rather than cultured organisms, suggesting the novelty of HMO-2011 and the prevalence of this phage type in the oceans. A significant number of the viral metagenome sequences obtained from the ocean surface were best assigned to the HMO-2011 genome. The number of reads assigned to HMO-2011 accounted for 10.3%-25.3% of the total reads assigned to viruses in seven viromes from the Pacific and Indian Oceans, making the HMO-2011 genome the most or second-most frequently assigned viral genome. Given its ability to infect the abundant SAR116 clade and its widespread distribution, Puniceispirillum phage HMO-2011 could be an important resource for marine virus research.

Complete nucleotide sequence of Bacillus subtilis (natto) bacteriophage PM1, a phage associated with disruption of food production.

Science.gov (United States)

Umene, Kenichi; Shiraishi, Atsushi

2013-06-01

"Natto", considered a traditional food, is made by fermenting boiled soybeans with Bacillus subtilis (natto), which is a natto-producing strain related to B. subtilis. The production of natto is disrupted by phage infections of B. subtilis (natto); hence, it is necessary to control phage infections. PM1, a phage of B. subtilis (natto), was isolated during interrupted natto production in a factory. In a previous study, PM1 was classified morphologically into the family Siphoviridae, and its genome, comprising approximately 50 kbp of linear double-stranded DNA, was assumed to be circularly permuted. In the present study, the complete nucleotide sequence of the PM1 genomic DNA of 50,861 bp (41.3 %G+C) was determined, and 86 open reading frames (ORFs) were deduced. Forty-one ORFs of PM1 shared similarities with proteins deduced from the genome of phages reported so far. Twenty-three ORFs of PM1 were associated with functions related to the phage multiplication process of gene control, DNA replication/modification, DNA packaging, morphogenesis, and cell lysis. Bacillus subtilis (natto) produces a capsular polypeptide of glutamate with a γ-linkage (called poly-γ-glutamate), which appears to serve as a physical barrier to phage adsorption. One ORF of PM1 had similarity with a poly-γ-glutamate hydrolase, which is assumed to degrade the capsular barrier to allow phage progenies to infect encapsulated host cells. The genome analysis of PM1 revealed the characteristics of the phage that are consistent as Bacillus subtilis (natto)-infecting phage.

A tale of tails: Sialidase is key to success in a model of phage therapy against K1-capsulated Escherichia coli

International Nuclear Information System (INIS)

Bull, J.J.; Vimr, E.R.; Molineux, I.J.

2010-01-01

Prior studies treating mice infected with Escherichia coli O18:K1:H7 observed that phages requiring the K1 capsule for infection (K1-dep) were superior to capsule-independent (K1-ind) phages. We show that three K1-ind phages all have low fitness when grown on cells in serum whereas fitnesses of four K1-dep phages were high. The difference is serum-specific, as fitnesses in broth overlapped. Sialidase activity was associated with all K1-dep virions tested but no K1-ind virions, a phenotype supported by sequence analyses. Adding endosialidase to cells infected with K1-ind phage increased fitness in serum by enhancing productive infection after adsorption. We propose that virion sialidase activity is the primary determinant of high fitness on cells grown in serum, and thus in a mammalian host. Although the benefit of sialidase is specific to K1-capsulated bacteria, this study may provide a scientific rationale for selecting phages for therapeutic use in many systemic infections.

Genomics of phages with therapeutic potential

DEFF Research Database (Denmark)

Zschach, Henrike

Bacteriophages, viruses that prey on bacteria, have been applied since the 1920’s to treat and prevent bacterial infection. After the discovery of antibiotics, this route was however largely abandoned. Now, with antimicrobial resistance in human-pathogenic bacteria on the rise and a dire need...... for alternatives, phage therapy once again takes center stage. Phage therapy holds the promise of substantial benefits both from the economic as well as the public health perspective but also holds distinct challenges. The aim of this PhD was to address how bioinformatics tools, specifically genomics...... and mathematical modelling, can be applied to move the field towards a future of actual phage therapy in humans. It is composed of three related research projects. The first part of this thesis is an introduction to various topics and methods relevant to the research projects that jointedly make up this Ph...

Comparative genomics and functional analysis of the 936 group of lactococcal Siphoviridae phages

NARCIS (Netherlands)

Murphy, James; Bottacini, Francesca; Mahony, Jennifer; Kelleher, Philip; Neve, Horst; Zomer, Aldert; Nauta, Arjen; van Sinderen, Douwe

2016-01-01

Genome sequencing and comparative analysis of bacteriophage collections has greatly enhanced our understanding regarding their prevalence, phage-host interactions as well as the overall biodiversity of their genomes. This knowledge is very relevant to phages infecting Lactococcus lactis, since they

Genomic analysis of WCP30 Phage of Weissella cibaria for Dairy Fermented Foods.

Science.gov (United States)

Lee, Young-Duck; Park, Jong-Hyun

2017-01-01

In this study, we report the morphogenetic analysis and genome sequence of a new WCP30 phage of Weissella cibaria , isolated from a fermented food. Based on its morphology, as observed by transmission electron microscopy, WCP30 phage belongs to the family Siphoviridae . Genomic analysis of WCP30 phage showed that it had a 33,697-bp double-stranded DNA genome with 41.2% G+C content. Bioinformatics analysis of the genome revealed 35 open reading frames. A BLASTN search showed that WCP30 phage had low sequence similarity compared to other phages infecting lactic acid bacteria. This is the first report of the morphological features and complete genome sequence of WCP30 phage, which may be useful for controlling the fermentation of dairy foods.

Incidence of uterine post abortion infection at Hospital de Clínicas de Porto Alegre. Is prophylactic antibiotic necessary?

Directory of Open Access Journals (Sweden)

Carine Luíze Panke

Full Text Available OBJECTIVE: To identify the incidence of pelvic infection after miscarriage undergoing uterine evacuation in a tertiary hospital in southern Brazil and to compare with the international literature.METHODS: we reviewed electronic medical records of the Hospital de Clinicas de Porto Alegre of all patients who underwent uterine evacuation for miscarriage between August 2008 and January 2012 were reviewed. We included all patients submitted to uterine curettage due to abortion and who had outpatient visits for review after the procedure. We calculated emographic and laboratory data of the study population, number needed for treatment (NNT and number needed to harm (NNH.RESULTS: of the 857 revised electronic medical records, 377 patients were subjected to uterine evacuation for miscarriage; 55 cases were lost to follow-up, leaving 322 cases that were classified as not infected abortion on admission. The majority of the population was white (79%; HIV prevalence and positive VDRL was 0.3% and 2%, respectively. By following these 322 cases for a minimum of seven days, it was found that the incidence of post-procedure infection was 1.8% (95% CI 0.8 to 4. The NNT and NNH calculated for 42 months were 63 and 39, respectively.CONCLUSION: The incidence of post-abortion infection between August 2008 to January 2012 was 1.8% (0.8 to 4.

Impedance Measurements Could Accelerate Phage-Based Identification of Bacillus anthracis and Other Bacteria

Science.gov (United States)

2016-09-01

Impedance Measurements Could Accelerate Phage-Based Identification of Bacillus anthracis And Other Bacteria Thomas Brown, Salwa Shan, Teresa...infection can be detected as early as one hour after exposing as few as 105 CFU bacteria to the stressor. We predicted that similar responses could be used... bacteria to form confluent growth and for phage-induced plaques to appear. Techniques that permit faster detection of species-specific bacteria /phage

Primary Isolation Strain Determines Both Phage Type and Receptors Recognised by Campylobacter jejuni Bacteriophages

DEFF Research Database (Denmark)

Sørensen, Martine C. Holst; Gencay, Yilmaz Emre; Birk, Tina

2015-01-01

were identified based on host range analysis and genome restriction profiles. Most phages were isolated using C. jejuni strains NCTC12662 and RM1221 and interestingly phage genome size (140 kb vs. 190 kb), host range and morphological appearance correlated with the isolation strain. Thus, according......In this study we isolated novel bacteriophages, infecting the zoonotic bacterium Campylobacter jejuni. These phages may be used in phage therapy of C. jejuni colonized poultry to prevent spreading of the bacteria to meat products causing disease in humans. Many C. jejuni phages have been isolated...... therefore chose seven C. jejuni strains each expressing different CPS structures as indicator strains in a large screening for phages in samples collected from free-range poultry farms. Forty-three phages were isolated using C. jejuni NCTC12658, NCTC12662 and RM1221 as host strains and 20 distinct phages...

A comparative study of induced abortions before and after legalization of abortions.

Science.gov (United States)

Malhotra, S; Devi, P K

1979-06-01

Abortion was legalized in many states in India in April 1972. This study deals with 2 groups of patients admitted to P.G.I., Chadigarh, with problems of induced septic abortion. Group 1 consisted of 88 patients admitted during the 2 1/2 year period from 1 July 1969 to 31 December 1971, before the legalization of abortion. Group 2 consists of 133 patients admitted during the 2 1/2 year period from 1 July 1973 to 31 December 1975. 1 year after the new abortion law had been in force. Not only has there been an increase in the total number of patients, there has been an increase in the severity of infection. Evidently, the liberalization of the law has encouraged more patients to seek abortions and has encouraged more doctors, lacking proper qualifications, to perform them. The morbidity and mortality with induced septic abortion can only be reduced if enough public propaganda makes the people especially in rural areas conscious of the hazards of induced abortion by "dais" and unqualified personnel, simultaneously making them aware of the provision of law and facilities available at different centers. Meanwhile, the law against unskilled and untrained personnel should be rigorously enforced.

Engineered phages for electronics.

Science.gov (United States)

Cui, Yue

2016-11-15

Phages are traditionally widely studied in biology and chemistry. In recent years, engineered phages have attracted significant attentions for functionalization or construction of electronic devices, due to their specific binding, catalytic, nucleating or electronic properties. To apply the engineered phages in electronics, these are a number of interesting questions: how to engineer phages for electronics? How are the engineered phages characterized? How to assemble materials with engineered phages? How are the engineered phages micro or nanopatterned? What are the strategies to construct electronics devices with engineered phages? This review will highlight the early attempts to address these questions and explore the fundamental and practical aspects of engineered phages in electronics, including the approaches for selection or expression of specific peptides on phage coat proteins, characterization of engineered phages in electronics, assembly of electronic materials, patterning of engineered phages, and construction of electronic devices. It provides the methodologies and opens up ex-cit-ing op-por-tu-ni-ties for the development of a variety of new electronic materials and devices based on engineered phages for future applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Viruses in the marine environment: community dynamics, phage-host interactions and genomic structure

OpenAIRE

Lara de la Casa, Elena

2014-01-01

There are an estimated 1030 viruses in the world oceans, the majority of which are phages (viruses that infect bacteria). Extensive research has demonstrated the significant influence of marine phages on microbial abundance, community structure, genetic exchange and global biogeochemical cycles. In this thesis, we contribute to increase the knowledge about the ecological role of viruses in marine systems, but also we aimed to provide a better understanding about the interactions between phage...

The Human Gut Phage Community and Its Implications for Health and Disease.

Science.gov (United States)

Manrique, Pilar; Dills, Michael; Young, Mark J

2017-06-08

In this review, we assess our current understanding of the role of bacteriophages infecting the human gut bacterial community in health and disease. In general, bacteriophages contribute to the structure of their microbial communities by driving host and viral diversification, bacterial evolution, and by expanding the functional diversity of ecosystems. Gut bacteriophages are an ensemble of unique and shared phages in individuals, which encompass temperate phages found predominately as prophage in gut bacteria (prophage reservoir) and lytic phages. In healthy individuals, only a small fraction of the prophage reservoir is activated and found as extracellular phages. Phage community dysbiosis is characterized by a shift in the activated prophage community or an increase of lytic phages, and has been correlated with disease, suggesting that a proper balance between lysis and lysogeny is needed to maintain health. Consequently, the concept of microbial dysbiosis might be extended to the phage component of the microbiome as well. Understanding the dynamics and mechanisms to restore balance after dysbiosis is an active area of research. The use of phage transplants to re-establish health suggests that phages can be used as disease treatment. Such advances represent milestones in our understanding of gut phages in human health and should fuel research on their role in health and disease.

In vivo efficiency evaluation of a phage cocktail in controlling severe colibacillosis in confined conditions and experimental poultry houses.

Science.gov (United States)

Oliveira, Ana; Sereno, Rui; Azeredo, Joana

2010-12-15

Infections caused by avian pathogenic Escherichia coli (APEC) cause important economic losses to poultry industry. The studies presented herein, aimed at investigating the in vivo performance of a cocktail of three phages in treating severe respiratory E. coli infections in experimentally contaminated birds and naturally infected flocks. Three lytic coliphages, phi F78E (Myoviridae), phi F258E (Siphoviridae) and phi F61E (Myoviridae) were combined in a 5.0 × 10(7)PFU/ml cocktail to be used in naturally APEC infected flocks (refractive to antibiotherapy). Experimentally infected birds were treated with phi F78E at two different titres (10(7)PFU/ml and 10(9)PFU/ml). Phage administration was performed orally and by spray, in a single application. The morbidity, mortality and pathology scores were compared with control birds not receiving phage therapy. The results revealed that the success of phage therapy in experimental rooms was dosage dependent, being 10(7)PFU/ml not enough to treat the infected chickens whereas a concentration of 10(9)PFU/ml of phi F78E allowed a decrease of 25% and 43% in chickens' mortality and morbidity, respectively. In the large scale experiments, the results obtained showed a remarkable efficacy of the low titre phage cocktail (10(7)PFU/ml) in decreasing the flocks' mortality to levels below 0.5% in no more than 3 weeks, with no recidivism. Based on the results we can conclude that phage treatment is a valuable alternative to control APEC infections in poultry. Copyright © 2010 Elsevier B.V. All rights reserved.

Targeting mammalian organelles with internalizing phage (iPhage) libraries

Science.gov (United States)

Rangel, Roberto; Dobroff, Andrey S.; Guzman-Rojas, Liliana; Salmeron, Carolina C.; Gelovani, Juri G.; Sidman, Richard L.; Pasqualini, Renata; Arap, Wadih

2015-01-01

Techniques largely used for protein interaction studies and discovery of intracellular receptors, such as affinity capture complex purification and yeast two-hybrid, may produce inaccurate datasets due to protein insolubility, transient or weak protein interactions, or irrelevant intracellular context. A versatile tool to overcome these limitations as well as to potentially create vaccines and engineer peptides and antibodies as targeted diagnostic and therapeutic agents, is the phage display technique. We have recently developed a new technology for screening internalizing phage (iPhage) vectors and libraries utilizing a ligand/receptor-independent mechanism to penetrate eukaryotic cells. iPhage particles provide a unique discovery platform for combinatorial intracellular targeting of organelle ligands along with their corresponding receptors and to fingerprint functional protein domains in living cells. Here we explain the design, cloning, construction, and production of iPhage-based vectors and libraries, along with basic ligand-receptor identification and validation methodologies for organelle receptors. An iPhage library screening can be performed in ~8 weeks. PMID:24030441

Genetic evidence for the involvement of the S-layer protein gene sap and the sporulation genes spo0A, spo0B, and spo0F in Phage AP50c infection of Bacillus anthracis.

Science.gov (United States)

Plaut, Roger D; Beaber, John W; Zemansky, Jason; Kaur, Ajinder P; George, Matroner; Biswas, Biswajit; Henry, Matthew; Bishop-Lilly, Kimberly A; Mokashi, Vishwesh; Hannah, Ryan M; Pope, Robert K; Read, Timothy D; Stibitz, Scott; Calendar, Richard; Sozhamannan, Shanmuga

2014-03-01

In order to better characterize the Bacillus anthracis typing phage AP50c, we designed a genetic screen to identify its bacterial receptor. Insertions of the transposon mariner or targeted deletions of the structural gene for the S-layer protein Sap and the sporulation genes spo0A, spo0B, and spo0F in B. anthracis Sterne resulted in phage resistance with concomitant defects in phage adsorption and infectivity. Electron microscopy of bacteria incubated with AP50c revealed phage particles associated with the surface of bacilli of the Sterne strain but not with the surfaces of Δsap, Δspo0A, Δspo0B, or Δspo0F mutants. The amount of Sap in the S layer of each of the spo0 mutant strains was substantially reduced compared to that of the parent strain, and incubation of AP50c with purified recombinant Sap led to a substantial reduction in phage activity. Phylogenetic analysis based on whole-genome sequences of B. cereus sensu lato strains revealed several closely related B. cereus and B. thuringiensis strains that carry sap genes with very high similarities to the sap gene of B. anthracis. Complementation of the Δsap mutant in trans with the wild-type B. anthracis sap or the sap gene from either of two different B. cereus strains that are sensitive to AP50c infection restored phage sensitivity, and electron microscopy confirmed attachment of phage particles to the surface of each of the complemented strains. Based on these data, we postulate that Sap is involved in AP50c infectivity, most likely acting as the phage receptor, and that the spo0 genes may regulate synthesis of Sap and/or formation of the S layer.

Novel Variants of Streptococcus thermophilus Bacteriophages Are Indicative of Genetic Recombination among Phages from Different Bacterial Species

DEFF Research Database (Denmark)

Szymczak, Paula; Janzen, Thomas; Neves, Ana Rute

2017-01-01

lactis P335 phages. Phage CHPC1151 was closely related to the atypical S. thermophilus phage 5093, homologous with a nondairy streptococcal prophage. By testing adsorption of the related streptococcal and lactococcal phages to the surface of S. thermophilus and L. lactis strains, we revealed....... thermophilus phages from the Chr. Hansen A/S collection, using PCR specific for the cos- or pac-type phages, as well as for the V2 antireceptor region. Three phages did not produce positive results with the assays. Analysis of phage morphologies indicated that two of these phages, CHPC577 and CHPC926, had...... the possibility of cross-interactions. Our data indicated that the use of S. thermophilus together with L. lactis, extensively applied for dairy fermentations, triggered the recombination between phages infecting different bacterial species. A notable diversity among S. thermophilus phage populations requires...

Characterization of Salmonella Typhimurium isolates from domestically acquired infections in Finland by phage typing, antimicrobial susceptibility testing, PFGE and MLVA.

Science.gov (United States)

Lienemann, Taru; Kyyhkynen, Aino; Halkilahti, Jani; Haukka, Kaisa; Siitonen, Anja

2015-07-02

providing better discrimination of the most common phage types. Furthermore, 5-loci MLVA was a less laborious method and easier to interpret than XbaI-PFGE. Thus, the laboratory-based surveillance of the Finnish human STM infections has been conducted with a combination of phage typing, antimicrobial susceptibility testing and 5-loci MLVA since January 2014.

Characterization and Complete Genome Sequences of Three N4-Like Roseobacter Phages Isolated from the South China Sea.

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Li, Baolian; Zhang, Si; Long, Lijuan; Huang, Sijun

2016-09-01

Three bacteriophages (RD-1410W1-01, RD-1410Ws-07, and DS-1410Ws-06) were isolated from the surface water of Sanya Bay, northern South China Sea, on two marine bacteria type strains of the Roseobacter lineage. These phages have an isometric head and a short tail, morphologically belonging to the Podoviridae family. Two of these phages can infect four of seven marine roseobacter strains tested and the other one can infect three of them, showing relatively broader host ranges compared to known N4-like roseophages. One-step growth curves showed that these phages have similar short latent periods (1-2 h) but highly variable burst sizes (27-341 pfu cell(-1)). Their complete genomes show high level of similarities to known N4-like roseophages in terms of genome size, G + C content, gene content, and arrangement. The morphological and genomic features of these phages indicate that they belong to the N4likevirus genus. Moreover, comparative genomic analysis based on 43 N4-like phages (10 roseobacter phages and 33 phages infecting other lineages of bacteria) revealed a core genome of 18 genes shared by all the 43 phages and 38 genes shared by all the ten roseophages. The 38 core genes of N4-like roseophages nearly make up 70 % of each genome in length. Phylogenetic analysis based on the concatenated core gene products showed that our phage isolates represent two new phyletic branches, suggesting the broad genetic diversity of marine N4-like roseophages remains.

Phage adsorption and lytic propagation in Lactobacillus plantarum: Could host cell starvation affect them?

OpenAIRE

Briggiler Marc?, Mari?ngeles; Reinheimer, Jorge; Quiberoni, Andrea

2015-01-01

Background Bacteriophages constitute a great threat to the activity of lactic acid bacteria used in industrial processes. Several factors can influence the infection cycle of bacteriophages. That is the case of the physiological state of host cells, which could produce inhibition or delay of the phage infection process. In the present work, the influence of Lactobacillus plantarum host cell starvation on phage B1 adsorption and propagation was investigated. Result First, cell growth kinetics ...

INFLUENCE OF ELECTROACUPUNCTURE ON ARTIFICIAL ABORTION-INDUCED SIDE EFFECTS

Institute of Scientific and Technical Information of China (English)

田丽颖

2001-01-01

In the present study, the effect of electroecupuncture (EA) of acupoints of Ren, Spleen and Stomach Meridians on artificial abortion-induced side effects was observed in 100 artificial abortion women. In comparison with 45 artificial abortion women in the control group (who had not accepted EA treatment), EA possessed significant effects in relieving abdominal pain, reducing vaginal bleeding duration, lowering infection rate and infertility rate after artificial abortion operation.

On the lack of host-cell reactivation of UV-irradiated phage T5

International Nuclear Information System (INIS)

Chiang, T.; Harm, W.

1976-01-01

Previously reported experiments have shown that host-cell reactivation (HCR) of UV-irradiated phage T1 in excision-repair proficient Escherichia coli cells is inhibited by superinfection with phage T5. Theoretical considerations have led to predictions concerning the dependence of repair inhibition on the multiplicity of superinfecting T5 phage and on the UV fluence to which they were exposed. These predictions have been supported by experimental results described in this paper. The fluence dependence permitted calculation of the relative UV sensitivity of the gene function responsible for repair inhibition; it was found to be about 2.3% that of the plaque-forming ability of phage T5. The T5-inhibitable step in excision repair occurs early in the infective cycle of T1. Furthermore, experiments involving the presence of 400 μg/ml chloramphenicol showed that HCR inhibition of T1 is caused by a protein produced after the FST segment of T5 (i.e. the first 8% of the T5 genome) has entered the host cell. A previously described minor T1 recovery process, occuring in both excision-repair-proficient and -deficient host-cells, is inhibited by T5 infection due to a different substance, which is most likely associated with the 'second-step-transfer' region of T5 DNA (involving the remainder of the genome). Superinfection with T4v 1 phage resulted in HCR inhibition of T1, resembling that observed after T5 superinfection. The discussion of these results suggests that inhibition of the bacterial excision repair system by T5 or T4 infection occurs at the level of UV-endonucleolytic incision, and that lack of HCR both in T-even phages and in T5 can be explained in the same manner

Is phage therapy acceptable in the immunocompromised host?

Science.gov (United States)

Borysowski, Jan; Górski, Andrzej

2008-09-01

Over the last decade, bacteriophages (bacterial viruses) have emerged as the major alternative to antibiotics in the treatment of antibiotic-resistant infections. While a considerable body of evidence has accumulated for the efficacy and safety of phage therapy in immunocompetent patients, data remain relatively scarce regarding its use in the immunocompromised host. To our knowledge, the present article is the first to summarize all findings, of both experimental and clinical studies, that may be relevant to the employment of phage therapy in immunocompromised patients. The available data suggest that bacteriophages could also be an efficacious and safe therapeutic modality in such patients.

The temperate Burkholderia phage AP3 of the Peduovirinae shows efficient antimicrobial activity against B. cenocepacia of the IIIA lineage.

Science.gov (United States)

Roszniowski, Bartosz; Latka, Agnieszka; Maciejewska, Barbara; Vandenheuvel, Dieter; Olszak, Tomasz; Briers, Yves; Holt, Giles S; Valvano, Miguel A; Lavigne, Rob; Smith, Darren L; Drulis-Kawa, Zuzanna

2017-02-01

Burkholderia phage AP3 (vB_BceM_AP3) is a temperate virus of the Myoviridae and the Peduovirinae subfamily (P2likevirus genus). This phage specifically infects multidrug-resistant clinical Burkholderia cenocepacia lineage IIIA strains commonly isolated from cystic fibrosis patients. AP3 exhibits high pairwise nucleotide identity (61.7 %) to Burkholderia phage KS5, specific to the same B. cenocepacia host, and has 46.7-49.5 % identity to phages infecting other species of Burkholderia. The lysis cassette of these related phages has a similar organization (putative antiholin, putative holin, endolysin, and spanins) and shows 29-98 % homology between specific lysis genes, in contrast to Enterobacteria phage P2, the hallmark phage of this genus. The AP3 and KS5 lysis genes have conserved locations and high amino acid sequence similarity. The AP3 bacteriophage particles remain infective up to 5 h at pH 4-10 and are stable at 60 °C for 30 min, but are sensitive to chloroform, with no remaining infective particles after 24 h of treatment. AP3 lysogeny can occur by stable genomic integration and by pseudo-lysogeny. The lysogenic bacterial mutants did not exhibit any significant changes in virulence compared to wild-type host strain when tested in the Galleria mellonella moth wax model. Moreover, AP3 treatment of larvae infected with B. cenocepacia revealed a significant increase (P < 0.0001) in larvae survival in comparison to AP3-untreated infected larvae. AP3 showed robust lytic activity, as evidenced by its broad host range, the absence of increased virulence in lysogenic isolates, the lack of bacterial gene disruption conditioned by bacterial tRNA downstream integration site, and the absence of detected toxin sequences. These data suggest that the AP3 phage is a promising potent agent against bacteria belonging to the most common B. cenocepacia IIIA lineage strains.

Comparative Omics and Trait Analyses of Marine Pseudoalteromonas Phages Advance the Phage OTU Concept

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Melissa B. Duhaime

2017-07-01

Full Text Available Viruses influence the ecology and evolutionary trajectory of microbial communities. Yet our understanding of their roles in ecosystems is limited by the paucity of model systems available for hypothesis generation and testing. Further, virology is limited by the lack of a broadly accepted conceptual framework to classify viral diversity into evolutionary and ecologically cohesive units. Here, we introduce genomes, structural proteomes, and quantitative host range data for eight Pseudoalteromonas phages isolated from Helgoland (North Sea, Germany and use these data to advance a genome-based viral operational taxonomic unit (OTU definition. These viruses represent five new genera and inform 498 unaffiliated or unannotated protein clusters (PCs from global virus metagenomes. In a comparison of previously sequenced Pseudoalteromonas phage isolates (n = 7 and predicted prophages (n = 31, the eight phages are unique. They share a genus with only one other isolate, Pseudoalteromonas podophage RIO-1 (East Sea, South Korea and two Pseudoalteromonas prophages. Mass-spectrometry of purified viral particles identified 12–20 structural proteins per phage. When combined with 3-D structural predictions, these data led to the functional characterization of five previously unidentified major capsid proteins. Protein functional predictions revealed mechanisms for hijacking host metabolism and resources. Further, they uncovered a hybrid sipho-myovirus that encodes genes for Mu-like infection rarely described in ocean systems. Finally, we used these data to evaluate a recently introduced definition for virus populations that requires members of the same population to have >95% average nucleotide identity across at least 80% of their genes. Using physiological traits and genomics, we proposed a conceptual model for a viral OTU definition that captures evolutionarily cohesive and ecologically distinct units. In this trait-based framework, sensitive hosts are

Reversing bacterial resistance to antibiotics by phage-mediated delivery of dominant sensitive genes.

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Edgar, Rotem; Friedman, Nir; Molshanski-Mor, Shahar; Qimron, Udi

2012-02-01

Pathogen resistance to antibiotics is a rapidly growing problem, leading to an urgent need for novel antimicrobial agents. Unfortunately, development of new antibiotics faces numerous obstacles, and a method that resensitizes pathogens to approved antibiotics therefore holds key advantages. We present a proof of principle for a system that restores antibiotic efficiency by reversing pathogen resistance. This system uses temperate phages to introduce, by lysogenization, the genes rpsL and gyrA conferring sensitivity in a dominant fashion to two antibiotics, streptomycin and nalidixic acid, respectively. Unique selective pressure is generated to enrich for bacteria that harbor the phages carrying the sensitizing constructs. This selection pressure is based on a toxic compound, tellurite, and therefore does not forfeit any antibiotic for the sensitization procedure. We further demonstrate a possible way of reducing undesirable recombination events by synthesizing dominant sensitive genes with major barriers to homologous recombination. Such synthesis does not significantly reduce the gene's sensitization ability. Unlike conventional bacteriophage therapy, the system does not rely on the phage's ability to kill pathogens in the infected host, but instead, on its ability to deliver genetic constructs into the bacteria and thus render them sensitive to antibiotics prior to host infection. We believe that transfer of the sensitizing cassette by the constructed phage will significantly enrich for antibiotic-treatable pathogens on hospital surfaces. Broad usage of the proposed system, in contrast to antibiotics and phage therapy, will potentially change the nature of nosocomial infections toward being more susceptible to antibiotics rather than more resistant.

Comparative genomics defines the core genome of the growing N4-like phage genus and identifies N4-like Roseophage specific genes

Directory of Open Access Journals (Sweden)

Jacqueline Zoe-Munn Chan

2014-10-01

Full Text Available Two bacteriophages, RPP1 and RLP1, infecting members of the marine Roseobacter clade were isolated from seawater. Their linear genomes are 74.7 and 74.6 kb and encode 91 and 92 coding DNA sequences, respectively. Around 30% of these are homologous to genes found in Enterobacter phage N4. Comparative genomics of these two new Roseobacter phages and twenty-three other sequenced N4-like phages (three infecting members of the Roseobacter lineage and twenty infecting other Gammaproteobacteria revealed that N4-like phages share a core genome of 14 genes responsible for control of gene expression, replication and virion proteins. Phylogenetic analysis of these genes placed the five N4-like roseophages (RN4 into a distinct subclade. Analysis of the RN4 phage genomes revealed they share a further 19 genes of which nine are found exclusively in RN4 phages and four appear to have been acquired from their bacterial hosts. Proteomic analysis of the RPP1 and RLP1 virions identified a second structural module present in the RN4 phages similar to that found in the Pseudomonas N4-like phage LIT1. Searches of various metagenomic databases, included the GOS database, using CDS sequences from RPP1 suggests these phages are widely distributed in marine environments in particular in the open ocean environment.

Immune response in bovine neosporosis: Protection or contribution to the pathogenesis of abortion.

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Almería, Sonia; Serrano-Pérez, Beatriz; López-Gatius, Fernando

2017-08-01

Neospora caninum is a protozoan parasite with a preference for cattle and dogs as hosts. When N. caninum infection occurs in cattle it induces abortion, bovine neosporosis being a main cause of abortion worldwide. In dairy cattle, the economic burden of neosporosis-associated abortion is so great that it might results in closure of a farm. However, not all infected cows abort and it is not yet understood why this occurs. At present there is no effective treatment or vaccine. This review provides insights on how immune response against the parasite determines protection or contribution to abortion. Aspects on markers of risk of abortion are also discussed. Humoral immune responses are not protective against N. caninum but seropositivity and antibody level can be good markers for a diagnosis of bovine neosporosis and its associated abortion risk. In addition, humoral mechanisms against N. caninum infection and abortion differ in pure-breed and cross-breed pregnant dairy and beef cattle. Concentrations of Pregnancy Associated glycoprotein -2 (PAG-2) can also be used to predict abortion. A partially protective immune response encompasses increased IFN-γ expression, which has to be counterbalanced by other cytokines such as IL-12 and IL-10, especially towards the end of pregnancy. Although IFN-γ is required to limit parasite proliferation a critical threshold of the IFN-γ response is also required to limit adverse effects on pregnancy. In clinical terms, it may be stated that IFN-γ production and cross-breed pregnancy can protect Neospora-infected dairy cows against abortion. Published by Elsevier Ltd.

Effects of abortion legalization in Nepal, 2001-2010.

Directory of Open Access Journals (Sweden)

Jillian T Henderson

Full Text Available Abortion was legalized in Nepal in 2002, following advocacy efforts highlighting high maternal mortality from unsafe abortion. We sought to assess whether legalization led to reductions in the most serious maternal health consequences of unsafe abortion.We conducted retrospective medical chart review of all gynecological cases presenting at four large public referral hospitals in Nepal. For the years 2001-2010, all cases of spontaneous and induced abortion complications were identified, abstracted, and coded to classify cases of serious infection, injury, and systemic complications. We used segmented Poisson and ordinary logistic regression to test for trend and risks of serious complications for three time periods: before implementation (2001-2003, early implementation (2004-2006, and later implementation (2007-2010.23,493 cases of abortion complications were identified. A significant downward trend in the proportion of serious infection, injury, and systemic complications was observed for the later implementation period, along with a decline in the risk of serious complications (OR 0.7, 95% CI 0.64, 0.85. Reductions in sepsis occurred sooner, during early implementation (OR 0.6, 95% CI 0.47, 0.75.Over the study period, health care use and the population of reproductive aged women increased. Total fertility also declined by nearly half, despite relatively low contraceptive prevalence. Greater numbers of women likely obtained abortions and sought hospital care for complications following legalization, yet we observed a significant decline in the rate of serious abortion morbidity. The liberalization of abortion policy in Nepal has benefited women's health, and likely contributes to falling maternal mortality in the country. The steepest decline was observed after expansion of the safe abortion program to include midlevel providers, second trimester training, and medication abortion, highlighting the importance of concerted efforts to improve

Effects of abortion legalization in Nepal, 2001-2010.

Science.gov (United States)

Henderson, Jillian T; Puri, Mahesh; Blum, Maya; Harper, Cynthia C; Rana, Ashma; Gurung, Geeta; Pradhan, Neelam; Regmi, Kiran; Malla, Kasturi; Sharma, Sudha; Grossman, Daniel; Bajracharya, Lata; Satyal, Indira; Acharya, Shridhar; Lamichhane, Prabhat; Darney, Philip D

2013-01-01

Abortion was legalized in Nepal in 2002, following advocacy efforts highlighting high maternal mortality from unsafe abortion. We sought to assess whether legalization led to reductions in the most serious maternal health consequences of unsafe abortion. We conducted retrospective medical chart review of all gynecological cases presenting at four large public referral hospitals in Nepal. For the years 2001-2010, all cases of spontaneous and induced abortion complications were identified, abstracted, and coded to classify cases of serious infection, injury, and systemic complications. We used segmented Poisson and ordinary logistic regression to test for trend and risks of serious complications for three time periods: before implementation (2001-2003), early implementation (2004-2006), and later implementation (2007-2010). 23,493 cases of abortion complications were identified. A significant downward trend in the proportion of serious infection, injury, and systemic complications was observed for the later implementation period, along with a decline in the risk of serious complications (OR 0.7, 95% CI 0.64, 0.85). Reductions in sepsis occurred sooner, during early implementation (OR 0.6, 95% CI 0.47, 0.75). Over the study period, health care use and the population of reproductive aged women increased. Total fertility also declined by nearly half, despite relatively low contraceptive prevalence. Greater numbers of women likely obtained abortions and sought hospital care for complications following legalization, yet we observed a significant decline in the rate of serious abortion morbidity. The liberalization of abortion policy in Nepal has benefited women's health, and likely contributes to falling maternal mortality in the country. The steepest decline was observed after expansion of the safe abortion program to include midlevel providers, second trimester training, and medication abortion, highlighting the importance of concerted efforts to improve access. Other

An orthologue of the cor gene is involved in the exclusion of temperate lambdoid phages. Evidence that Cor inactivates FhuA receptor functions

International Nuclear Information System (INIS)

Uc-Mass, Augusto; Loeza, Eva Jacinto; Garza, Mireya de la; Guarneros, Gabriel; Hernandez-Sanchez, Javier; Kameyama, Luis

2004-01-01

A new set of lambdoid phages (mEp) classified into different immunity groups was previously described. Phages mEp213, mEp237, and mEp410 were unable to grow in mEp167 lysogenic cells, presumably due to an exclusion mechanism expressed constitutively by the mEp167 repressed prophage. In this work, to analyze the exclusion phenomenon, we constructed a genomic library from mEp167 phage in a pPROEX derivative plasmid. A DNA fragment containing an open reading frame for a 77 amino acid polypeptide was selected by its ability to confer resistance to heteroimmune phage infection. This ORF shows high amino acid sequence identity with putative Cor proteins of phages HK022, φ80 and N15. Cells expressing the mEp167 cor gene from a plasmid (Cor + phenotype) excluded 13 of 20 phages from different infection immunity groups. This exclusion was observed in both tonB - and tonB + cells. Lambdoid mEp phages that were excluded in these cells were unable to infect cells defective in the outer membrane FhuA receptor (fhuA - ). Thus, Cor-mediated exclusion was only observed in fhuA + cells. Phage production after DNA transfection or the spontaneous induction of mEp prophage in Cor + cells was not blocked. In addition, ferrichrome uptake, which is mediated by FhuA, was inhibited in Cor + cells. Our results show that not only phage infection via FhuA but also a FhuA transport activity (ferrichrome uptake) are inhibited by Cor, presumably by inactivation of FhuA

The role of zoonotic chlamydial agents in ruminants abortion.

Science.gov (United States)

Barati, Sara; Moori-Bakhtiari, Naghmeh; Najafabadi, Masoud Ghorbanpoor; Momtaz, Hassan; Shokuhizadeh, Leili

2017-10-01

Enzootic abortion of ewes (EAE) is caused by infection of sheep and goats by Chlamydia abortus bacterium. Chlamydial abortion in bovine could occur by Chlamydia abortus, Chlamydia psittaci and Chlamydia pecorum. C. psittaci is the causative agent of psittacosis or ornithosis disease in humans and birds. It also causes acute pneumonia in cattle and sheep. The present study aimed at surveying the role of chlamydial agents in ruminants abortion. A total of 117 aborted material samples (Cotyledon, liver, spleen, and abomasal contents of fetus) from 9 cattle and 100 sheep in Shahr-e-Kord and 8 sheep from Bagh-e-Malek were collected from different herds with abortion history during the lambing periods from 2014 to 2016. After DNA extraction, the samples were tested by species-specific PCR to detect C. abortus, C. pecorum and C. psittaci. Out of 117 clinical sample (108 sheep and 9 cattle), chlamydial infection was detected in 66 (56.41%) samples by Chlamydiales order-specific primers. A total of 24 (36.36%) and 24 (36.36%) samples indicated positive forms of C. abortus and C. psittasi infections, respectively. Only 1 (1.5%) C. pecorum was identified from cattle using nested PCR during this study. Among 66 Chlamydiales -positive samples, 20 (30.30%) samples with coinfection of C. abortus and C. psittaci were detected, however, infection of 3 species was not detected in the samples. Because of the high percentage of chlamydial infection in these regions and probability of coinfection, conducting epidemiological studies on the role of different animals is highly recommended.

Phage transposon mutagenesis.

Science.gov (United States)

Siegrist, M Sloan; Rubin, Eric J

2009-01-01

Phage transduction is an attractive method of genetic manipulation in mycobacteria. PhiMycoMarT7 is well suited for transposon mutagenesis as it is temperature sensitive for replication and contains T7 promoters that promote transcription, a highly active transposase gene, and an Escherichia coli oriR6 K origin of replication. Mycobacterial transposon mutant libraries produced by PhiMycoMarT7 transduction are amenable to both forward and reverse genetic studies. In this protocol, we detail the preparation of PhiMycoMarT7, including a description of the phage, reconstitution of the phage, purification of plaques, preparation of phage stock, and titering of phage stock. We then describe the transduction procedure and finally outline the isolation of individual transposon mutants.

Reproductive tract infections in women seeking abortion in Vietnam

DEFF Research Database (Denmark)

Nguyen, My Huong; Kurtzhals, Jørgen; Do, Thi Thu Thuy

2009-01-01

BACKGROUND: Women requesting abortion are at increased risk of developing RTI complications. However, RTI control in many resource-poor countries including Vietnam have been faced with logistical and methodological problems due to lack of standardized definitions of RTIs, lack of well-validated d......BACKGROUND: Women requesting abortion are at increased risk of developing RTI complications. However, RTI control in many resource-poor countries including Vietnam have been faced with logistical and methodological problems due to lack of standardized definitions of RTIs, lack of well......-validated diagnostic criteria, lack of accurate laboratory tests, and lack of diagnostic equipment and skills. This article investigates the prevalence of RTIs among Vietnamese abortion-seeking women, to evaluate the available diagnostic techniques, and to assess antibiotic resistance among aetiological agents of RTI....... METHOD: The study was conducted in Phu-San hospital (PSH) from December 2003 through April 2004 among 748 abortion clients. A structured questionnaire was used to collect data on socio-economic and reproductive characteristics. Specimens were collected for laboratory analyses of chlamydia, gonorrhoea...

Phage and bacteria support mutual diversity in a narrowing staircase of coexistence

DEFF Research Database (Denmark)

Härter, Jan Olaf Mirko; Mitarai, Namiko; Sneppen, Kim

2014-01-01

arms race will typically favor high growth rate, but a phage that infects two bacterial strains differently can occasionally eliminate the fastest growing bacteria. This context-dependent fitness allows abrupt resetting of the 'Red-Queen's race' and constrains the local diversity.......The competitive exclusion principle states that phage diversity M should not exceed bacterial diversity N. By analyzing the steady-state solutions of multistrain equations, we find a new constraint: the diversity N of bacteria living on the same resources is constrained to be M or M+1 in terms...... of the diversity of their phage predators. We quantify how the parameter space of coexistence exponentially decreases with diversity. For diversity to grow, an open or evolving ecosystem needs to climb a narrowing 'diversity staircase' by alternatingly adding new bacteria and phages. The unfolding coevolutionary...

Characterization and Testing the Efficiency of Acinetobacter baumannii Phage vB-GEC_Ab-M-G7 as an Antibacterial Agent

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Ia Kusradze

2016-10-01

Full Text Available Acinetobacter baumannii is a gram-negative, non-motile bacterium that, due to its multidrug resistance, has become a major nosocomial pathogen .The increasing number of multidrug resistant (MDR strains has renewed interest in phage therapy. The aim of our study was to assess the effectiveness of phage administration in Acinetobacter baumannii wound infections in an animal model to demonstrate phage therapy as non-toxic, safe and alternative antibacterial remedy. Using classical methods for the study of bacteriophage properties, we characterized phage vB-GEC_Ab-M-G7 as a dsDNA myovirus with a 90kb genome size. Important characteristics of vB-GEC_Ab-M-G7include a short latent period and large burst size, wide host range, resistance to chloroform and thermal and pH stability. In a rat wound model, phage application effectively decreased the number of bacteria isolated from the wounds of successfully treated animals. This study highlights the effectiveness of the phage therapy and provides further insight into treating infections caused by MDR strains using phage administration.

The Lytic SA Phage Demonstrate Bactericidal Activity against Mastitis Causing Staphylococcus aureus

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Hamza Ameer

2016-01-01

Full Text Available Staphylococcus aureus is the major causative agent of mastitis among dairy animals as it causes intramammary gland infection. Due to antibiotic resistance and contamination of antibiotics in the milk of diseased animals; alternative therapeutic agents are required to cure mastitis. Lytic bacteriophages and their gene products can be potential therapeutic agents against bacteria as they are host specific and less harmful than antibiotics. In this study, Staphylococcus aureus were isolated from milk samples of the infected animals and identified biochemically. SA phage was isolated from sewage water showing lytic activity against Staphylococcus aureus isolates. The highest lytic activity of bacteriophages was observed at 37°C and pH 7, and the most suitable storage condition was at 4°C. SA phage efficiently reduced bacterial growth in the bacterial reduction assay. The characterization and bacterial growth reduction activity of the bacteriophages against Staphylococcus aureus signifies their underlying potential of phage therapy against mastitis.

Genetic exchanges caused by ultraviolet photoproducts in phage lamda DNA molecules: the role of DNA replication

International Nuclear Information System (INIS)

Lin, P.F.; Howard-Flanders, P.; Yale Univ., New Haven, Conn.

1976-01-01

Genetic recombination induced by structural damage in DNA molecules was investigated in E. coli K12(lamda) lysogens infected with genetically marked phage lamda. Photoproducts were induced in the phage DNA before infection by exposing them either to 313 nm light in the presence of acetophenone or to 254 nm light. To test the role of the replication of the damage phage DNA on the frequency of the induced recombination , both heteroimmune and homoimmune crosses were performed, and scored for P + recombinants. In heteroimmune crosses, recombination was less frequent in infected cells exposed to visible light and in wild type cells able to perform excision repair than in excision-defective lysogens. Therefore, much of the induced recombination can be attributed to the pyrimidine dimers in the phage DNA. In homoimmune crosses, replication of the phage DNA containing ultraviolet photoproducts was represented by lamda immunity, and was further blocked by the lack of the P gene product needed for replication. The 254 nm photoproducts increased the frequency of recombination in these homoimmune crosses, even though phage DNA replication was blocked. Irradiation with 313 nm light and acetophenone M, which produces dimers and unknown photoproducts, was not as effective per dimer as the 254 nm light. It is concluded from these results that certain unidentified 254 nm photoproducts can cause recombination even in the absence of DNA replication. They are not pyrimidine dimers, as they are not susceptible to excision repair or photoreactivation. In contrast, pyrimidine dimers appear to cause recombination only when the DNA containing them undergoes replication. (orig./MG) [de

Phage-mediated dispersal of biofilm and distribution of bacterial virulence genes is induced by quorum sensing.

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Friederike S Rossmann

2015-02-01

Full Text Available The microbiome and the phage meta-genome within the human gut are influenced by antibiotic treatments. Identifying a novel mechanism, here we demonstrate that bacteria use the universal communication molecule AI-2 to induce virulence genes and transfer them via phage release. High concentrations (i.e. 100 μM of AI-2 promote dispersal of bacteria from already established biofilms, and is associated with release of phages capable of infecting other bacteria. Enterococcus faecalis V583ΔABC harbours 7 prophages in its genome, and a mutant deficient in one of these prophages (i.e. prophage 5 showed a greatly reduced dispersal of biofilm. Infection of a probiotic E. faecalis strain without lytic prophages with prophage 5 resulted in increased biofilm formation and also in biofilm dispersal upon induction with AI-2. Infection of the probiotic E. faecalis strain with phage-containing supernatants released through AI-2 from E. faecalis V583ΔABC resulted in a strong increase in pathogenicity of this strain. The polylysogenic probiotic strain was also more virulent in a mouse sepsis model and a rat endocarditis model. Both AI-2 and ciprofloxacin lead to phage release, indicating that conditions in the gastrointestinal tract of hospitalized patients treated with antibiotics might lead to distribution of virulence genes to apathogenic enterococci and possibly also to other commensals or even to beneficial probiotic strains.

Characterization and complete genome sequence analysis of a novel virulent Siphoviridae phage against Staphylococcus aureus isolated from bovine mastitis in Xinjiang, China.

Science.gov (United States)

Zhang, Qian; Xing, Shaozhen; Sun, Qiang; Pei, Guangqian; Cheng, Shi; Liu, Yannan; An, Xiaoping; Zhang, Xianglilan; Qu, Yonggang; Tong, Yigang

2017-06-01

Bovine mastitis is one of the most costly diseases in dairy cows worldwide. It can be caused by over 150 different microorganisms, where Staphylococcus aureus is the most frequently isolated and a major pathogen responsible for heavy economic losses in dairy industry. Although antibiotic therapy is most widely used, alternative treatments are necessary due to the increasing antibiotic resistance. Using phage for pathogen control is a promising tool in the fight against antibiotic resistance. Mainly using high-throughput sequencing, bioinformatics and our proposed phage termini identification method, we have isolated and characterized a novel virulent phage, designated as vB_SauS_IMEP5, from manure collected from dairy farms in Shihezi, Xinjiang, China, for use as a biocontrol agent against Staphylococcus aureus infections. Its latent period was about 30 min and its burst size was approximately 272PFU/cell. Phage vB_SauS_IMEP5 survives in a wide pH range between 3 and 12. A treatment at 70 °C for 20 min can inactive the phage. Morphological analysis of vB_SauS_IMEP5 revealed that phage vB_SauS_IMEP5 morphologically resembles phages in the family Siphoviridae. Among our tested multiplicity of infections (MOIs), the optimal multiplicity of infection (MOI) of this phage was determined to be 0.001, suggesting that phage vB_SauS_IMEP5 has high bacteriolytic potential and good efficiency for reducing bacterial growth. The complete genome of IME-P5 is a 44,677-bp, linear, double-stranded DNA, with a G+C content of 34.26%, containing 69 putative ORFs. The termini of genome were determined with next-generation sequencing data using our previously proposed termini identification method, which suggests that this phage has non-redundant termini with 9nt 3' protruding cohesive ends. The genomic and proteomic characteristics of IMEP5 demonstrate that this phage does not belong to any of the previously recognized Siphoviridae Staphylococcus phage groups, suggesting the

Phage morphology recapitulates phylogeny: the comparative genomics of a new group of myoviruses.

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André M Comeau

Full Text Available Among dsDNA tailed bacteriophages (Caudovirales, members of the Myoviridae family have the most sophisticated virion design that includes a complex contractile tail structure. The Myoviridae generally have larger genomes than the other phage families. Relatively few "dwarf" myoviruses, those with a genome size of less than 50 kb such as those of the Mu group, have been analyzed in extenso. Here we report on the genome sequencing and morphological characterization of a new group of such phages that infect a diverse range of Proteobacteria, namely Aeromonas salmonicida phage 56, Vibrio cholerae phages 138 and CP-T1, Bdellovibrio phage φ1422, and Pectobacterium carotovorum phage ZF40. This group of dwarf myoviruses shares an identical virion morphology, characterized by usually short contractile tails, and have genome sizes of approximately 45 kb. Although their genome sequences are variable in their lysogeny, replication, and host adaption modules, presumably reflecting differing lifestyles and hosts, their structural and morphogenesis modules have been evolutionarily constrained by their virion morphology. Comparative genomic analysis reveals that these phages, along with related prophage genomes, form a new coherent group within the Myoviridae. The results presented in this communication support the hypothesis that the diversity of phages may be more structured than generally believed and that the innumerable phages in the biosphere all belong to discrete lineages or families.

Four linked outbreaks of Salmonella enteritidis phage type 4 infection--the continuing egg threat.

Science.gov (United States)

Ejidokun, O O; Killalea, D; Cooper, M; Holmyard, S; Cross, A; Kemp, C

2000-06-01

Four outbreaks of Salmonella enteritidis phage type (PT) 4 occurred among guests at functions for which a single commercial caterer supplied food. Retrospective cohort studies were used to describe the epidemiology of three of these outbreaks and identify the vehicle(s) responsible. Of 172 guests at these three events, 47 fitted the clinical case definition for illness and 24 cases were confirmed to have S. enteritidis PT4 infection. Food containing raw egg was identified epidemiologically as the likely vehicle of infection in two of the three outbreaks (odds ratios (OR) and 95% confidence intervals 9.1 (2.2-39.9) and 6.9 (1.2-46.4)). Logistic regression analysis yielded OR = 10.7 (p = 0.0022) and OR = 9.3 (p = 0.015) for egg consumption in two of the outbreaks. These outbreaks highlighted the continuing need to remind the public and commercial caterers of the potential high risks of contracting salmonella from shell eggs. Education of caterers includes advice to obtain eggs and other products from reputable and identifiable suppliers.

Characterization and lytic activity of methicillin-resistant Staphylococcus aureus(MRSA phages isolated from NICU

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Golnar Rahimzadeh

2016-06-01

Full Text Available Background Methicillin-resistant Staphylococcus aureus (MRSA is a well-known pathogen that causes serious diseases in humans. As part of the efforts to control this pathogen, an isolated bacteriophage, Siphoviridae, which specifically targets Methicillin-resistant Staphylococcus aureus (MRSA, was characterized. Aims The objective of this study was to characterize of a virulent bacteriophage (Siphoviridae isolated from a NICU bathroom sink. Methods The MRSA strain was isolated from patient blood. The isolated strain was confirmed as MRSA using conventional methods. Phages were isolated from a NICU bathroom sink and activity was lytic as determined by spot test. Titer phage lysate was measured by the Double Layer Agar (DLA technique. The morphology was found with electron microscopy. The single-step growth curve was plotted. Results Electron microscopy showed the phage as a member of the family Siphoviridae, serogroup A and F. The isolated phage was capable of lytic activity against methicillin-resistant Staphylococcus aureus (MRSA strain as shown by spot test. By DLA, the titre of the phages was determined to be 10×108PFU/ml. The single-step growth curve showed that the latent period of the isolated bacteriophage was 30 min and the total number of viable progeny per infected host, burst size, was 2600 PFU/infected host. Conclusion In this study, two phages were isolated and characterized from a NICU bathroom sink, from the Siphoviridae family, which specifically targetsmethicillin-resistant Staphylococcus aureus (MRSA.

Radiosensitivity of the induction of early enzymes by. gamma. -irradiated T7-phages

Energy Technology Data Exchange (ETDEWEB)

Bopp, E

1975-01-01

The radiosensitivity of the ability of the bacteriophage T7 to produce polymerase and lysozyme during its reproduction cycle is investigated. B-cells of Escherichia coli were infected with /sup 60/Co-..gamma..-irradiated T7 phages. From the extracts of the cells opened by ultrasonic waves, the amount of enzymes produced is determined with the aid of special enzyme tests. The fraction of inactivated phages able to produce RNA polymerase is higher than the fraction with intact DNA double strands and higher than the fraction able to inject DNA. The lowest fraction is that of inactivated phages producing lysozyme.

Heterogeneity in Induction Level, Infection Ability, and Morphology of Shiga Toxin-Encoding Phages (Stx Phages) from Dairy and Human Shiga Toxin-Producing Escherichia coli O26:H11 Isolates

Science.gov (United States)

Bonanno, Ludivine; Petit, Marie-Agnès; Loukiadis, Estelle; Michel, Valérie

2016-01-01

Shiga toxin (Stx)-producing Escherichia coli (STEC) bacteria are foodborne pathogens responsible for diarrhea and hemolytic-uremic syndrome (HUS). Shiga toxin, the main STEC virulence factor, is encoded by the stx gene located in the genome of a bacteriophage inserted into the bacterial chromosome. The O26:H11 serotype is considered to be the second-most-significant HUS-causing serotype worldwide after O157:H7. STEC O26:H11 bacteria and their stx-negative counterparts have been detected in dairy products. They may convert from the one form to the other by loss or acquisition of Stx phages, potentially confounding food microbiological diagnostic methods based on stx gene detection. Here we investigated the diversity and mobility of Stx phages from human and dairy STEC O26:H11 strains. Evaluation of their rate of in vitro induction, occurring either spontaneously or in the presence of mitomycin C, showed that the Stx2 phages were more inducible overall than Stx1 phages. However, no correlation was found between the Stx phage levels produced and the origin of the strains tested or the phage insertion sites. Morphological analysis by electron microscopy showed that Stx phages from STEC O26:H11 displayed various shapes that were unrelated to Stx1 or Stx2 types. Finally, the levels of sensitivity of stx-negative E. coli O26:H11 to six Stx phages differed among the 17 strains tested and our attempts to convert them into STEC were unsuccessful, indicating that their lysogenization was a rare event. PMID:26826235

Complete Genome Sequence of EtG, the First Phage Sequenced from Erwinia tracheiphila.

Science.gov (United States)

Andrade-Domínguez, Andrés; Kolter, Roberto; Shapiro, Lori R

2018-02-22

Erwinia tracheiphila is the causal agent of bacterial wilt of cucurbits. Here, we report the genome sequence of the temperate phage EtG, which was isolated from an E. tracheiphila -infected cucumber plant. Phage EtG has a linear 30,413-bp double-stranded DNA genome with cohesive ends and 45 predicted open reading frames. Copyright © 2018 Andrade-Domínguez et al.

Inhibition of bacterial conjugation by phage M13 and its protein g3p: quantitative analysis and model.

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Abraham Lin

Full Text Available Conjugation is the main mode of horizontal gene transfer that spreads antibiotic resistance among bacteria. Strategies for inhibiting conjugation may be useful for preserving the effectiveness of antibiotics and preventing the emergence of bacterial strains with multiple resistances. Filamentous bacteriophages were first observed to inhibit conjugation several decades ago. Here we investigate the mechanism of inhibition and find that the primary effect on conjugation is occlusion of the conjugative pilus by phage particles. This interaction is mediated primarily by phage coat protein g3p, and exogenous addition of the soluble fragment of g3p inhibited conjugation at low nanomolar concentrations. Our data are quantitatively consistent with a simple model in which association between the pili and phage particles or g3p prevents transmission of an F plasmid encoding tetracycline resistance. We also observe a decrease in the donor ability of infected cells, which is quantitatively consistent with a reduction in pili elaboration. Since many antibiotic-resistance factors confer susceptibility to phage infection through expression of conjugative pili (the receptor for filamentous phage, these results suggest that phage may be a source of soluble proteins that slow the spread of antibiotic resistance genes.

Lysis from without

Science.gov (United States)

2011-01-01

In this commentary I consider use of the term “lysis from without” (LO) along with the phenomenon's biological relevance. LO originally described an early bacterial lysis induced by high-multiplicity virion adsorption and that occurs without phage production (here indicated as LOV). Notably, this is more than just high phage multiplicities of adsorption leading to bacterial killing. The action on bacteria of exogenously supplied phage lysin, too, has been described as a form of LO (here, LOL). LOV has been somewhat worked out mechanistically for T4 phages, has been used to elucidate various phage-associated phenomena including discovery of the phage eclipse, may be relevant to phage ecology, and, with resistance to LO (LOR), is blocked by certain phage gene products. Speculation as to the impact of LOV on phage therapy also is fairly common. Since LOV assays are relatively easily performed and not all phages are able to induce LOV, a phage's potential to lyse bacteria without first infecting should be subject to at least in vitro experimental confirmation before the LOV label is applied. The term “abortive infection” may be used more generally to describe non-productive phage infections that kill bacteria. PMID:21687534

Liposome Entrapment of Bacteriophages Improves Wound Healing in a Diabetic Mouse MRSA Infection

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Sanjay Chhibber

2018-03-01

Full Text Available Diabetic populations are more prone to developing wound infections which results in poor and delayed wound healing. Infection with drug resistant organisms further worsen the situation, driving searches for alternative treatment approaches such as phage therapy. Major drawback of phage therapy, however, is low phage persistence in situ, suggesting further refinement of the approach. In the present work we address this issue by employing liposomes as delivery vehicles. A liposome entrapped phage cocktail was evaluated for its ability to resolve a Staphylococcus aureus-induced diabetic excission wound infection. Two characterized S. aureus specific lytic phages, MR-5 and MR-10 alone, in combination (cocktail, or entrapped in liposomes (versus as free phages were assesed for their therapeutic efficacy in resolving diabetic wound infection. Mice treated with free phage cocktail showed significant reduction in wound bioburden, greater wound contraction and faster tissue healing than with free monophage therapy. However, to further enhance the availability of viable phages the encapsulation of phage cocktail in the liposomes was done. Results of in vitro stability studies and in vivo phage titer determination, suggests that liposomal entrapment of phage cocktail can lead to better phage persistence at the wound site. A 2 log increase in phage titre, however, was observed at the wound site with liposome entrapped as compared to the free phage cocktail, and this was associaed with increased rates of infection resolution and wound healing. Entrapment of phage cocktails within liposomes thus could represent an attractive approach for treatment of bacterial infections, not responding to antibiotis as increased phage persistence in vitro and in vivo at the wound site was observed.

Stumbling across the same phage

DEFF Research Database (Denmark)

Kalatzis, Panagiotis; Rørbo, Nanna Iben; Castillo Bermúdez, Daniel Elías

2017-01-01

46,006 and 54,201 bp. All 19 phages showed high genetic similarity, and 13 phages were genetically identical. Apart from sporadically distributed single nucleotide polymorphisms (SNPs), genetic diversifications were located in three variable regions (VR1, VR2 and VR3) in six of the phage genomes...... was lysogenized by the temperate phages and a genomic analysis of a collection of 31 virulent V. anguillarum showed that the isolated phages were present as prophages in >50% of the strains covering large geographical distances. Further, phage sequences were widely distributed among CRISPR-Cas arrays of publicly...... available sequenced Vibrios. The observed distribution of these specific temperate Vibriophages across large geographical scales may be explained by efficient dispersal of phages and bacteria in the marine environment combined with a mutualistic interaction between temperate phages and their hosts which...

Characterization of novel virulent broad-host-range phages of Xylella fastidiosa and Xanthomonas.

Science.gov (United States)

Ahern, Stephen J; Das, Mayukh; Bhowmick, Tushar Suvra; Young, Ry; Gonzalez, Carlos F

2014-01-01

The xylem-limited bacterium Xylella fastidiosa is the causal agent of several plant diseases, most notably Pierce's disease of grape and citrus variegated chlorosis. We report the isolation and characterization of the first virulent phages for X. fastidiosa, siphophages Sano and Salvo and podophages Prado and Paz, with a host range that includes Xanthomonas spp. Phages propagated on homologous hosts had observed adsorption rate constants of ~4 × 10(-12) ml cell(-1) min(-1) for X. fastidiosa strain Temecula 1 and ~5 × 10(-10) to 7 × 10(-10) ml cell(-1) min(-1) for Xanthomonas strain EC-12. Sano and Salvo exhibit >80% nucleotide identity to each other in aligned regions and are syntenic to phage BcepNazgul. We propose that phage BcepNazgul is the founding member of a novel phage type, to which Sano and Salvo belong. The lysis genes of the Nazgul-like phage type include a gene that encodes an outer membrane lipoprotein endolysin and also spanin gene families that provide insight into the evolution of the lysis pathway for phages of Gram-negative hosts. Prado and Paz, although exhibiting no significant DNA homology to each other, are new members of the phiKMV-like phage type, based on the position of the single-subunit RNA polymerase gene. The four phages are type IV pilus dependent for infection of both X. fastidiosa and Xanthomonas. The phages may be useful as agents for an effective and environmentally responsible strategy for the control of diseases caused by X. fastidiosa.

A Novel Application of Synthetic Biology and Directed Evolution to Engineer Phage-based Antibiotics

Energy Technology Data Exchange (ETDEWEB)

Wu, Meiye [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2014-09-01

The emergence of multiple drug resistant bacteria poses threats to human health, agriculture and food safety. Annually over 100,000 deaths and up to $20 billion loss to the U.S. economy are attributed to multiple drug resistant bacteria. With only four new chemical antibiotics in the drug development pipeline, we are in dire need of new solutions to address the emerging threat of multiple drug resistance. We propose a paradigm-changing approach to address the multi-drug resistant bacteria problem by utilizing Synthetic Biology (SynBio) methodologies to create and evolve “designer” bacteriophages or phages – viruses that specifically infect bacteria – to infect and kill newly emerging pathogenic bacterial strains WITHOUT the need for chemical antibiotics. A major advantage of using phage to combat pathogenic bacteria is that phages can co-evolve with their bacterial host, and Sandia can be the first in the world to establish an industrial scale Synthetic Biology pipeline for phage directed evolution for safe, targeted, customizable solution to bacterial drug resistance. Since there is no existing phage directed evolution effort within or outside of Sandia, this proposal is suitable as a high-risk LDRD effort to create the first pipeline for such an endeavor. The high potential reward nature of this proposal will be the immediate impact in decontamination and restoration of surfaces and infrastructure, with longer term impact in human or animal therapeutics. The synthetic biology and screening approaches will lead to fundamental knowledge of phage/bacteria co-evolution, making Sandia a world leader in directed evolution of bacteriophages.

Genetically Engineered Virulent Phage Banks in the Detection and Control of Emergent Pathogenic Bacteria

Science.gov (United States)

Blois, Hélène; Iris, François

2010-01-01

Natural outbreaks of multidrug-resistant microorganisms can cause widespread devastation, and several can be used or engineered as agents of bioterrorism. From a biosecurity standpoint, the capacity to detect and then efficiently control, within hours, the spread and the potential pathological effects of an emergent outbreak, for which there may be no effective antibiotics or vaccines, become key challenges that must be met. We turned to phage engineering as a potentially highly flexible and effective means to both detect and eradicate threats originating from emergent (uncharacterized) bacterial strains. To this end, we developed technologies allowing us to (1) concurrently modify multiple regions within the coding sequence of a gene while conserving intact the remainder of the gene, (2) reversibly interrupt the lytic cycle of an obligate virulent phage (T4) within its host, (3) carry out efficient insertion, by homologous recombination, of any number of engineered genes into the deactivated genomes of a T4 wild-type phage population, and (4) reactivate the lytic cycle, leading to the production of engineered infective virulent recombinant progeny. This allows the production of very large, genetically engineered lytic phage banks containing, in an E. coli host, a very wide spectrum of variants for any chosen phage-associated function, including phage host-range. Screening of such a bank should allow the rapid isolation of recombinant T4 particles capable of detecting (ie, diagnosing), infecting, and destroying hosts belonging to gram-negative bacterial species far removed from the original E. coli host. PMID:20569057

ORIGINAL ARTICLE: Multidrug Resistance and Phage Pattern of Staphylococcus aureus in Pyoderma Cases

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Sanjay M. Wavare

2012-01-01

Full Text Available Background: Pyoderma is common in India and other tropical countries. Staphylococcus aureus is the commonest causative agent ofpyoderma. Aims and Objectives: To know the antibiotic susceptibility and bacteriophage pattern of Staphylococcus aureus isolated from pyoderma infection. Materials and Methods: One hundred clinically diagnosed pyoderma cases were investigated bacteriologically. A total of 59 isolates of S. aureus were subjected to antibioticsusceptibility testing by Kirby Bauer’s disk diffusion method and phage typing by routine test dilution X 100 bacteriophages. Results: Most of the strains were resistant to penicillin, ampicillin and were susceptible to gentamicin, streptomycin and erythromycin. Multidrug resistance was also high among these strains. Regarding the phage types, Phage type 52 (15 strains, 96 (8 strains and 71(16strains were predominant among the typed strains (55.95% of S. aureus. The most common group was mixed phage group (17% followed by phage group I (13.55%. Conclusion: Knowledge of antibioticsusceptibility pattern is essential to give proper antibiotic therapy and avoid unnecessary medication with non-effective drugs, which may increase resistance. Gentamicin, streptomycin and erythromycin are the drugs of choice in that order. Association of phage typing and antibiotic sensitivity of S. aureus showed the predominance of phage group III with greater frequency of penicillin resistance.

Analysis of whole genome sequencing for the Escherichia coli O157:H7 typing phages.

Science.gov (United States)

Cowley, Lauren A; Beckett, Stephen J; Chase-Topping, Margo; Perry, Neil; Dallman, Tim J; Gally, David L; Jenkins, Claire

2015-04-08

Shiga toxin producing Escherichia coli O157 can cause severe bloody diarrhea and haemolytic uraemic syndrome. Phage typing of E. coli O157 facilitates public health surveillance and outbreak investigations, certain phage types are more likely to occupy specific niches and are associated with specific age groups and disease severity. The aim of this study was to analyse the genome sequences of 16 (fourteen T4 and two T7) E. coli O157 typing phages and to determine the genes responsible for the subtle differences in phage type profiles. The typing phages were sequenced using paired-end Illumina sequencing at The Genome Analysis Centre and the Animal Health and Veterinary Laboratories Agency and bioinformatics programs including Velvet, Brig and Easyfig were used to analyse them. A two-way Euclidian cluster analysis highlighted the associations between groups of phage types and typing phages. The analysis showed that the T7 typing phages (9 and 10) differed by only three genes and that the T4 typing phages formed three distinct groups of similar genomic sequences: Group 1 (1, 8, 11, 12 and 15, 16), Group 2 (3, 6, 7 and 13) and Group 3 (2, 4, 5 and 14). The E. coli O157 phage typing scheme exhibited a significantly modular network linked to the genetic similarity of each group showing that these groups are specialised to infect a subset of phage types. Sequencing the typing phage has enabled us to identify the variable genes within each group and to determine how this corresponds to changes in phage type.

[Abortion explained by a nurse].

Science.gov (United States)

Bastit i Costa, M A

1983-01-01

Abortion is the termination of pregnancy prior to the 180th day, during which time the fetus is not yet viable outside the womb. Spontaneous abortion is the body's expulsion of a fetus during the 1st months of pregnancy. It is usually not very painful, does not involve much bleeding, and is rarely complicated by infection. Spontaneous abortion is much more frequent at the outset of pregnancy and may occur unnoticed. Its causes are unknown in over half of cases. The most important causes are developmental problems in the products of conception. Causes of spontaneous abortions of maternal etiology are most frequently uterine malposition or malformation. Serious illness in the mother is a less common cause of spontaneous abortion than once believed. Induced abortion is caused by the destruction of a normally implanted and healthy embryo. Its complications are related to the amount of bleeding or the introduction of germs from outside which can spread rapidly. Placental retention is a danger of all induced abortions. Induced abortion is common and in some countries it even creates demographic problems. Abortion is legal in many countries as an expression of the right to choose, but in others it is only legal on therapeutic grounds. Defenders and detractors of abortion have written extensively about it, with some works being sincere and some only tactical. The great majority of moralists are opposed to abortion, while biologists and scientists are divided on the question. The Spanish penal code punishes all persons who cause the death of a fetus or impede the process of gestation. The Catholic Church has considered abortion a homicide and against divine and natural laws. Legal or illegal, it is certain that the number of abortions increases each day. In the face of this reality, the need is for measures to avoid abortion whenever possible. Sex education in schools, full information on contraceptive methods and creation of family planning centers are some means of

Computational Modelling of Large Scale Phage Production Using a Two-Stage Batch Process

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Konrad Krysiak-Baltyn

2018-04-01

Full Text Available Cost effective and scalable methods for phage production are required to meet an increasing demand for phage, as an alternative to antibiotics. Computational models can assist the optimization of such production processes. A model is developed here that can simulate the dynamics of phage population growth and production in a two-stage, self-cycling process. The model incorporates variable infection parameters as a function of bacterial growth rate and employs ordinary differential equations, allowing application to a setup with multiple reactors. The model provides simple cost estimates as a function of key operational parameters including substrate concentration, feed volume and cycling times. For the phage and bacteria pairing examined, costs and productivity varied by three orders of magnitude, with the lowest cost found to be most sensitive to the influent substrate concentration and low level setting in the first vessel. An example case study of phage production is also presented, showing how parameter values affect the production costs and estimating production times. The approach presented is flexible and can be used to optimize phage production at laboratory or factory scale by minimizing costs or maximizing productivity.

Colonisation of a phage susceptible Campylobacter jejuni population in two phage positive broiler flocks.

Directory of Open Access Journals (Sweden)

Sophie Kittler

Full Text Available The pathogens Campylobacter jejuni and Campylobacter coli are commensals in the poultry intestine and campylobacteriosis is one of the most frequent foodborne diseases in developed and developing countries. Phages were identified to be effective in reducing intestinal Campylobacter load and this was evaluated, in the first field trials which were recently carried out. The aim of this study was to further investigate Campylobacter population dynamics during phage application on a commercial broiler farm. This study determines the superiority in colonisation of a Campylobacter type found in a field trial that was susceptible to phages in in vitro tests. The colonisation factors, i.e. motility and gamma glutamyl transferase activity, were increased in this type. The clustering in phylogenetic comparisons of MALDI-TOF spectra did not match the ST, biochemical phenotype and phage susceptibility. Occurrence of Campylobacter jejuni strains and phage susceptibility types with different colonisation potential seem to play a very important role in the success of phage therapy in commercial broiler houses. Thus, mechanisms of both, phage susceptibility and Campylobacter colonisation should be further investigated and considered when composing phage cocktails.

57.1% of Unmarried Women Undergoing Abortion Have RTI：Survey

Institute of Scientific and Technical Information of China (English)

无

2004-01-01

A survey of 2,002 unmarried women under 24 years of age who requested abortions in four Chinese cities indicates that reproductive tract infection (RTI) has become a major factor affecting the reproductive health of unmarried women having abortions.

Safety analysis of a Russian phage cocktail: From MetaGenomic analysis to oral application in healthy human subjects

Energy Technology Data Exchange (ETDEWEB)

McCallin, Shawna, E-mail: semccallin@yahoo.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Alam Sarker, Shafiqul, E-mail: sasarker@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Barretto, Caroline, E-mail: Caroline.Barretto@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Sultana, Shamima, E-mail: shamima@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Berger, Bernard, E-mail: bernard.berger@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Huq, Sayeda, E-mail: sayeeda@mail.icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Krause, Lutz, E-mail: ltz.krause@gmail.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Bibiloni, Rodrigo, E-mail: Rodrigo.Bibiloni@agresearch.co.nz [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Schmitt, Bertrand, E-mail: bertrand.schmitt@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Reuteler, Gloria, E-mail: gloria.reuteler@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Brüssow, Harald, E-mail: harald.bruessow@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland)

2013-09-01

Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb, including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure. - Highlights: • We analyzed the composition of a commercial Russian phage cocktail. • The cocktail consists of at least 10 different phage genera. • No undesired genes were detected. • No adverse effects were seen upon oral application in a small human clinical trial.

Safety analysis of a Russian phage cocktail: From MetaGenomic analysis to oral application in healthy human subjects

International Nuclear Information System (INIS)

McCallin, Shawna; Alam Sarker, Shafiqul; Barretto, Caroline; Sultana, Shamima; Berger, Bernard; Huq, Sayeda; Krause, Lutz; Bibiloni, Rodrigo; Schmitt, Bertrand; Reuteler, Gloria; Brüssow, Harald

2013-01-01

Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb, including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure. - Highlights: • We analyzed the composition of a commercial Russian phage cocktail. • The cocktail consists of at least 10 different phage genera. • No undesired genes were detected. • No adverse effects were seen upon oral application in a small human clinical trial

Pyrimidine dimers are not the principal pre-mutagenic lesions induced in lambda phage DNA by ultraviolet light

International Nuclear Information System (INIS)

Wood, R.D.

1985-01-01

Experiments were performed to examine the role of cyclobutyl pyrimidine dimers in the process of mutagenesis by ultraviolet light. Lambda phage DNA was irradiated with u.v. and then incubated with an Escherichia coli photoreactivating enzyme, which monomerizes cyclobutyl pyrimidine dimers upon exposure to visible light. The photoreactivated DNA was packaged into lambda phage particles, which were used to infect E. coli uvr - host cells that had been induced for SOS functions by ultraviolet irradiation. Photoreactivation removed most toxic lesions from irradiated phage, but did not change the frequency of induction of mutations to the clear-plaque phenotype. This implies that cyclobutyl pyrimidine dimers can be lethal, but usually do not serve as sites of mutations in the phage. The DNA sequences of mutants, derived from photoreactivated DNA showed that almost two-thirds (16/28) were transitions, the same fraction found for u.v. mutagenesis without photoreactivation. Thus the lesion inducing transitions is not the cyclobutyl pyrimidine dimer. Photoreactivation of SOS-induced host cells before infection with u.v.-irradiated phage reduced mutagenesis substantially. In this case, photoreversal of cyclobutyl dimers serves to reduce expression of the SOS functions that are required in targeted u.v. mutagenesis. (author)

[Abortion in humans caused by Chlamydophila abortus (Chlamydia psittaci serovar 1)].

Science.gov (United States)

Pospischil, A; Thoma, R; Hilbe, M; Grest, P; Zimmermann, D; Gebbers, J O

2002-09-01

On a farm housing cattle and goats an abortion storm occurred affecting 50% of the goats during the lambing season 2000/2001. In one of three investigated caprine abortions Chlamydophila abortus could be identified as etiology. During this time a pregnant woman (pregnancy week 19/20) had contact with aborting goats. She developed a severe generalized infection and aborted. The placenta contained Chlamydophila abortus shown by immunohistochemistry and PCR. Aim of the present case report is to alert veterinarians about the potential zoonotic risk of ovine/caprine abortions.

Efficacy of potential phage cocktails against Vibrio harveyi and closely related Vibrio species isolated from shrimp aquaculture environment in the south east coast of India.

Science.gov (United States)

Stalin, Nattan; Srinivasan, Pappu

2017-08-01

A diverse set of novel phages infecting the marine pathogenic Vibrio harveyi was isolated from shrimp aquaculture environments in the south east coast of India. Based on initial screening, three phages with a broad host range revealed that the growth inhibition of phage is relatively specific to V. harveyi. They were also able to infect V. alginolyticus and V. parahemolyticus that belonged to the Harveyi clade species from shrimp pond and sea coast environment samples. However, the impact of these phages on their host bacterium are well understood; a one-step growth curve experiment and transmission electron microscope (TEM) revealed three phages grouped under the Myoviridae (VHM1 and VHM2); Siphoviridae (VHS1) family. These phages were further molecular characterized with respect to phage genomic DNA isolates. The randomly amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) digestion with HindIII, and major structural proteins were distinguished by sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) clearly indicated that all the phage isolates were different, even when they came from the same source, giving an insight into the diversity of phages. Evaluation of microcosm studies of Penaeus monodon larvae infected with V. harveyi (105 CFU mL-1) showed that larvae survival after 96 h in the presence of phage treatment at 109 PFU mL-1 was enhanced when compared with the control. The resolution in over survival highly recommended that this study provides the phage-based therapy which could be an innovative and eco-friendly solution against Vibrio disease in shrimp aquaculture and in the natural environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Vibrio Phage KVP40 Encodes a Functional NAD+ Salvage Pathway.

Science.gov (United States)

Lee, Jae Yun; Li, Zhiqun; Miller, Eric S

2017-05-01

+ for ADP-ribosylation of proteins involved in transcribing and translating the phage genome. We show here that phage KVP40 encodes a functional pyridine nucleotide scavenging pathway that is expressed during the metabolic period of the infection cycle. The pathway is conserved in other large, dsDNA phages in which the two genes, nadV and natV , share an evolutionary history in their respective phage-host group. Copyright © 2017 American Society for Microbiology.

Effects of Abortion Legalization in Nepal, 2001–2010

Science.gov (United States)

Henderson, Jillian T.; Puri, Mahesh; Blum, Maya; Harper, Cynthia C.; Rana, Ashma; Gurung, Geeta; Pradhan, Neelam; Regmi, Kiran; Malla, Kasturi; Sharma, Sudha; Grossman, Daniel; Bajracharya, Lata; Satyal, Indira; Acharya, Shridhar; Lamichhane, Prabhat; Darney, Philip D.

2013-01-01

Background Abortion was legalized in Nepal in 2002, following advocacy efforts highlighting high maternal mortality from unsafe abortion. We sought to assess whether legalization led to reductions in the most serious maternal health consequences of unsafe abortion. Methods We conducted retrospective medical chart review of all gynecological cases presenting at four large public referral hospitals in Nepal. For the years 2001–2010, all cases of spontaneous and induced abortion complications were identified, abstracted, and coded to classify cases of serious infection, injury, and systemic complications. We used segmented Poisson and ordinary logistic regression to test for trend and risks of serious complications for three time periods: before implementation (2001–2003), early implementation (2004–2006), and later implementation (2007–2010). Results 23,493 cases of abortion complications were identified. A significant downward trend in the proportion of serious infection, injury, and systemic complications was observed for the later implementation period, along with a decline in the risk of serious complications (OR 0.7, 95% CI 0.64, 0.85). Reductions in sepsis occurred sooner, during early implementation (OR 0.6, 95% CI 0.47, 0.75). Conclusion Over the study period, health care use and the population of reproductive aged women increased. Total fertility also declined by nearly half, despite relatively low contraceptive prevalence. Greater numbers of women likely obtained abortions and sought hospital care for complications following legalization, yet we observed a significant decline in the rate of serious abortion morbidity. The liberalization of abortion policy in Nepal has benefited women’s health, and likely contributes to falling maternal mortality in the country. The steepest decline was observed after expansion of the safe abortion program to include midlevel providers, second trimester training, and medication abortion, highlighting the importance

Antibody production in response to staphylococcal MS-1 phage cocktail in patients undergoing phage therapy

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Maciej Żaczek

2016-10-01

Full Text Available In this study, we investigated the humoral immune response (through the release of IgG, IgA, and IgM antiphage antibodies to a staphylococcal phage cocktail in patients undergoing experimental phage therapy at the Phage Therapy Unit, Medical Center of the Ludwik Hirszfeld Institute of Immunology and Experimental Therapy in Wrocław, Poland. We also evaluated whether occurring antiphage antibodies had neutralizing properties towards applied phages (K rate. Among 20 examined patients receiving the MS-1 phage cocktail orally and/or locally, the majority did not show a noticeably higher level of antiphage antibodies in their sera during phage administration. Even in those individual cases with an increased immune response, mostly by induction of IgG and IgM, the presence of antiphage antibodies did not translate into unsatisfactory clinical results of phage therapy. On the other hand, a negative outcome of the treatment occurred in some patients who showed relatively weak production of antiphage antibodies before and during treatment. This may imply that possible induction of antiphage antibodies is not an obstacle to the implementation of phage therapy and support our assumption that the outcome of the phage treatment does not primarily depend on the appearance of antiphage antibodies in sera of patients during therapy. These conclusions are in line with our previous findings. The confirmation of this thesis is of great interest as regards the efficacy of phage therapy in humans.

Antibody Production in Response to Staphylococcal MS-1 Phage Cocktail in Patients Undergoing Phage Therapy.

Science.gov (United States)

Żaczek, Maciej; Łusiak-Szelachowska, Marzanna; Jończyk-Matysiak, Ewa; Weber-Dąbrowska, Beata; Międzybrodzki, Ryszard; Owczarek, Barbara; Kopciuch, Agnieszka; Fortuna, Wojciech; Rogóż, Paweł; Górski, Andrzej

2016-01-01

In this study, we investigated the humoral immune response (through the release of IgG, IgA, and IgM antiphage antibodies) to a staphylococcal phage cocktail in patients undergoing experimental phage therapy at the Phage Therapy Unit, Medical Center of the Ludwik Hirszfeld Institute of Immunology and Experimental Therapy in Wrocław, Poland. We also evaluated whether occurring antiphage antibodies had neutralizing properties toward applied phages (K rate). Among 20 examined patients receiving the MS-1 phage cocktail orally and/or locally, the majority did not show a noticeably higher level of antiphage antibodies in their sera during phage administration. Even in those individual cases with an increased immune response, mostly by induction of IgG and IgM, the presence of antiphage antibodies did not translate into unsatisfactory clinical results of phage therapy. On the other hand, a negative outcome of the treatment occurred in some patients who showed relatively weak production of antiphage antibodies before and during treatment. This may imply that possible induction of antiphage antibodies is not an obstacle to the implementation of phage therapy and support our assumption that the outcome of the phage treatment does not primarily depend on the appearance of antiphage antibodies in sera of patients during therapy. These conclusions are in line with our previous findings. The confirmation of this thesis is of great interest as regards the efficacy of phage therapy in humans.

Commensal E. coli Stx2 lysogens produce high levels of phages after spontaneous prophage induction

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Hildegunn eIversen

2015-02-01

Full Text Available Enterohemorrhagic E. coli (EHEC is a food-borne pathogen that causes disease ranging from uncomplicated diarrhea to life-threatening hemolytic uremic syndrome (HUS and nervous system complications. Shiga toxin 2 (Stx2 is the major virulence factor of EHEC and is critical for development of HUS. The genes encoding Stx2 are carried by lambdoid bacteriophages and the toxin production is tightly linked to the production of phages during lytic cycle. It has previously been suggested that commensal E. coli could amplify the production of Stx2-phages and contribute to the severity of disease. In this study we examined the susceptibility of commensal E. coli strains to the Stx2-converting phage ϕ734, isolated from a highly virulent EHEC O103:H25 (NIPH-11060424. Among 38 commensal E. coli strains from healthy children below five years, 15 were lysogenized by the ϕ734 phage, whereas lytic infection was not observed. Three of the commensal E. coli ϕ734 lysogens were tested for stability, and appeared stable and retained the phage for at least 10 cultural passages. When induced to enter lytic cycle by H2O2 treatment, 8 out of 13 commensal lysogens produced more ϕ734 phages than NIPH-11060424. Strikingly, five of them even spontaneously (non-induced produced higher levels of phage than the H2O2 induced NIPH-11060424. An especially high frequency of HUS (60% was seen among children infected by NIPH-11060424 during the outbreak in 2006. Based on our findings, a high Stx2 production by commensal E. coli lysogens cannot be ruled out as a contributor to the high frequency of HUS during this outbreak.

AbiV, a Novel Antiphage Abortive Infection Mechanism on the Chromosome of Lactococcus lactis subsp. cremoris MG1363

DEFF Research Database (Denmark)

Haaber, Jakob Brandt Borup; Moineau, Sylvain; Fortier, Louis-Charles

2008-01-01

phenotype was caused by a chromosomal gene turned on by a promoter from the inserted construct. Reverse transcription-PCR analysis confirmed that there were higher levels of transcription of a downstream open reading frame (ORF) in the phage-resistant integrants than in the phage-sensitive strain L. lactis...... searches revealed no homology to other phage resistance mechanisms, and thus, this novel Abi mechanism was designated AbiV. The mode of action of AbiV is unknown, but the activity of AbiV prevented cleavage of the replicated phage DNA of 936-like phages....

Complete genome sequence of Vibrio anguillarum phage CHOED successfully used for phage therapy in aquaculture

DEFF Research Database (Denmark)

Romero, Jaime; Higuera, Gastón; Gajardo, Felipe

2014-01-01

Vibrio anguillarum phage CHOED was isolated from Chilean mussels. It is a virulent phage showing effective inhibition of V. anguillarum. CHOED has potential in phage therapy, because it can protect fish from vibriosis in fish farms. Here, we announce the completely sequenced genome of V....... anguillarum phage CHOED....

Are Phage Lytic Proteins the Secret Weapon To Kill Staphylococcus aureus?

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Diana Gutiérrez

2018-01-01

Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is one of the most threatening microorganisms for global human health. The current strategies to reduce the impact of S. aureus include a restrictive control of worldwide antibiotic use, prophylactic measures to hinder contamination, and the search for novel antimicrobials to treat human and animal infections caused by this bacterium. The last strategy is currently the focus of considerable research. In this regard, phage lytic proteins (endolysins and virion-associated peptidoglycan hydrolases [VAPGHs] have been proposed as suitable candidates. Indeed, these proteins display narrow-spectrum antimicrobial activity and a virtual lack of bacterial-resistance development. Additionally, the therapeutic use of phage lytic proteins in S. aureus animal infection models is yielding promising results, showing good efficacy without apparent side effects. Nonetheless, human clinical trials are still in progress, and data are not available yet. This minireview also analyzes the main obstacles for introducing phage lytic proteins as human therapeutics against S. aureus infections. Besides the common technological problems derived from large-scale production of therapeutic proteins, a major setback is the lack of a proper legal framework regulating their use. In that sense, the relevant health authorities should urgently have a timely discussion about these new antimicrobials. On the other hand, the research community should provide data to dispel any doubts regarding their efficacy and safety. Overall, the appropriate scientific data and regulatory framework will encourage pharmaceutical companies to invest in these promising antimicrobials.

Shiga toxin-converting phages and the emergence of new pathogenic Escherichia coli: a world in motion

Science.gov (United States)

Tozzoli, Rosangela; Grande, Laura; Michelacci, Valeria; Ranieri, Paola; Maugliani, Antonella; Caprioli, Alfredo; Morabito, Stefano

2014-01-01

Shiga toxin (Stx)-producing Escherichia coli (STEC) are pathogenic E. coli causing diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC are characterized by a constellation of virulence factors additional to Stx and have long been regarded as capable to cause HC and HUS when possessing the ability of inducing the attaching and effacing (A/E) lesion to the enterocyte, although strains isolated from such severe infections sometimes lack this virulence feature. Interestingly, the capability to cause the A/E lesion is shared with another E. coli pathogroup, the Enteropathogenic E. coli (EPEC). In the very recent times, a different type of STEC broke the scene causing a shift in the paradigm for HUS-associated STEC. In 2011, a STEC O104:H4 caused a large outbreak with more than 800 HUS and 50 deaths. Such a strain presented the adhesion determinants of Enteroaggregative E. coli (EAggEC). We investigated the possibility that, besides STEC and EAggEC, other pathogenic E. coli could be susceptible to infection with stx-phages. A panel of stx2-phages obtained from STEC isolated from human disease was used to infect experimentally E. coli strains representing all the known pathogenic types, including both diarrheagenic E. coli (DEC) and extra-intestinal pathogenic E. coli (ExPEC). We observed that all the E. coli pathogroups used in the infection experiments were susceptible to the infection. Our results suggest that the stx2-phages used may not have specificity for E. coli adapted to the intestinal environment, at least in the conditions used. Additionally, we could only observe transient lysogens suggesting that the event of stable stx2-phage acquisition occurs rarely. PMID:24999453

Secular and seasonal trends of Neospora abortion in California dairy cows.

Science.gov (United States)

Thurmond, M C; Anderson, M L; Blanchard, P C

1995-06-01

This study was undertaken to determine if the proportion of dairy cow abortions attributable to Neospora sp. infection increased or occurred in a seasonal cycle during a 6-yr period. Abortions caused by Neospora sp. were tallied for all fetuses submitted to the Tulare branch of the California Veterinary Diagnostic Laboratory between January 1985 and December 1990. Regression analysis of 221 cases of Neospora among 762 fetuses submitted showed a weak increasing secular trend (P = 0.053, r2 = 0.05), with predicted monthly proportions at the beginning and end of the 6 yr of 0.16 and 0.33, respectively. Using a Kolmogorov-Smirnov-type statistic, comparison of the 12-mo distribution of Neospora sp. cases and a hypothetical distribution of cows at risk of aborting found about 16% of variation in cases was attributable to season (P fall. Results indicate that Neospora sp. abortion in California dairy cows is not new or recently emerging and that seasonally related factors influence some of the risk of abortion. Results suggest that Neospora sp. has contributed to the high dairy cow abortion rate for many years, and that seasonally varying exposures may predispose to transmission or recrudescence of infection.

Abortion patients' perceptions of abortion regulation.

Science.gov (United States)

Cockrill, Kate; Weitz, Tracy A

2010-01-01

Most states regulate abortion differently than other health care services. Examples of these regulations include mandating waiting periods and the provision of state-authored information, and prohibiting private and public insurance coverage for abortion. The primary purpose of this paper is to explore abortion patients' perspectives on these regulations. We recruited 20 participants from three abortion providing facilities located in two states in the U.S. South and Midwest. Using a survey and semistructured interview, we collected information about women's knowledge of abortion regulation and policy preferences. During the interviews, women weighed the pros and cons of abortion regulations. We used grounded theory analytical techniques and matrix analysis to organize and interpret the data. We discovered five themes in these women's considerations of regulation: responsibility, empathy, safe and accessible health care, privacy, and equity. Women in the study generally supported policies that they felt protected women or informed decisions. However, most women also opposed laws mandating two-day abortion appointments for women who were traveling long distances. Women tended to favor financial coverage of abortion, arguing that it could help poor women afford abortion or reduce state expenditures. Overall the study participants' opinions on abortion policy reflect key values for advocates and policy makers to consider: responsibility, empathy, safe and accessible health care, privacy, and equity. Future work should examine abortion regulations in light of these shared values. Laws that promote misinformation or prohibit accommodations of unique circumstances are not consistent the positions articulated by the subjects in our study. Copyright 2010 Jacobs Institute of Women

Genomic, proteomic, morphological, and phylogenetic analyses of vB_EcoP_SU10, a podoviridae phage with C3 morphology.

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Mohammadali Khan Mirzaei

Full Text Available A recently isolated phage, vB_EcoP_SU10 (SU10, with the unusual elongated C3 morphotype, can infect a wide range of Escherichia coli strains. We have sequenced the genome of this phage and characterized it further by mass spectrometry based proteomics, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and ultra-thin section electron microscopy. The genome size is 77,327 base pairs and its genes, and genome architecture, show high similarity to the phiEco32 phage genes and genome. The TEM images reveal that SU10 have a quite long tail for being a Podoviridae phage, and that the tail also changes conformation upon infection. The ultra-thin section electron microscopy images of phages at the stage of replication within the host cell show that the phages form a honeycomb-like structure under packaging of genomes and assembly of mature capsids. This implies a tight link between the replication and cutting of the concatemeric genome, genome packaging, and capsid assembly. We have also performed a phylogenetic analysis of the structural genes common between Podoviridae phages of the C1 and C3 morphotypes. The result shows that the structural genes have coevolved, and that they form two distinct groups linked to their morphotypes. The structural genes of C1 and C3 phages appear to have diverged around 280 million years ago applying a molecular clock calibrated according to the presumed split between the Escherichia - Salmonella genera.

The promise of bacteriophage therapy for Burkholderia cepacia complex respiratory infections.

Directory of Open Access Journals (Sweden)

Diana Dawn Semler

2012-01-01

Full Text Available In recent times, increased attention has been given to evaluating the efficacy of phage therapy, especially in scenarios where the bacterial infectious agent of interest is highly antibiotic resistant. In this regard, phage therapy is especially applicable to infections caused by the Burkholderia cepacia complex (BCC since members of the BCC are antibiotic pan-resistant. Current studies in BCC phage therapy are unique from many other avenues of phage therapy research in that the research is not only comprised of phage isolation, in vitro phage characterization and in vivo infection model efficacy, but also adapting aerosol drug delivery techniques to aerosol phage formulation delivery and storage.

Abortion-Related Mortality in the United States 1998–2010

Science.gov (United States)

Zane, Suzanne; Creanga, Andreea A.; Berg, Cynthia J.; Pazol, Karen; Suchdev, Danielle B.; Jamieson, Denise J.; Callaghan, William M.

2015-01-01

OBJECTIVE To examine characteristics and causes of legal induced abortion–related deaths in the United States between 1998 and 2010. METHODS Abortion-related deaths were identified through the national Pregnancy Mortality Surveillance System with enhanced case-finding. We calculated the abortion mortality rate by race, maternal age, and gestational age and the distribution of causes of death by gestational age and procedure. RESULTS During the period from 1998–2010, of approximately 16.1 million abortion procedures, 108 women died, for a mortality rate of 0.7 deaths per 100,000 procedures overall, 0.4 deaths for non-Hispanic white women, 0.5 deaths for Hispanic women, and 1.1 deaths for black women. The mortality rate increased with gestational age, from 0.3 to 6.7 deaths for procedures performed at 8 weeks or less and at 18 weeks or greater, respectively. A majority of abortion-related deaths at 13 weeks of gestation or less were associated with anesthesia complications and infection, whereas a majority of abortion-related deaths at more than 13 weeks of gestation were associated with infection and hemorrhage. In 20 of the 108 cases, the abortion was performed as a result of a severe medical condition where continuation of the pregnancy threatened the woman’s life. CONCLUSION Deaths associated with legal induced abortion continue to be rare events—less than 1 per 100,000 procedures. Primary prevention of unintended pregnancy, including those in women with serious pre-existing medical conditions, and increased access to abortion services at early gestational ages may help to further decrease abortion-related mortality in the United States. PMID:26241413

CRISPR-cas-mediated phage resistance enhances horizontal gene transfer by transduction

NARCIS (Netherlands)

Watson, Bridget N.J.; Staals, Raymond H.J.; Fineran, Peter C.

2018-01-01

A powerful contributor to prokaryotic evolution is horizontal gene transfer (HGT) through transformation, conjugation, and transduction, which can be advantageous, neutral, or detrimental to fitness. Bacteria and archaea control HGT and phage infection through CRISPR-Cas (clustered regularly

Hobi-Like Pestivirus in Aborted Bovine Fetuses

OpenAIRE

Decaro, Nicola; Lucente, Maria Stella; Mari, Viviana; Sciarretta, Rossana; Pinto, Pierfrancesco; Buonavoglia, Domenico; Martella, Vito; Buonavoglia, Canio

2012-01-01

An outbreak of abortion affecting multiparous cows was associated with Hobi-like pestivirus infection. Viral RNA and antigens were detected in the tissues of two aborted fetuses. Molecular assays for other common abortogenic agents tested negative. At the genetic level, the Hobi-like pestivirus displayed the closest relatedness to Italian, Australian, and South American viruses, whereas it diverged from the prototype Thai isolate. These findings may have important implications for the pestivi...

Pseudomonas aeruginosa adaptation to lungs of cystic fibrosis patients leads to lowered resistance to phage and protist enemies.

Directory of Open Access Journals (Sweden)

Ville-Petri Friman

Full Text Available Pathogenic life styles can lead to highly specialized interactions with host species, potentially resulting in fitness trade-offs in other ecological contexts. Here we studied how adaptation of the environmentally transmitted bacterial pathogen, Pseudomonas aeruginosa, to cystic fibrosis (CF patients affects its survival in the presence of natural phage (14/1, ΦKZ, PNM and PT7 and protist (Tetrahymena thermophila and Acanthamoebae polyphaga enemies. We found that most of the bacteria isolated from relatively recently intermittently colonised patients (1-25 months, were innately phage-resistant and highly toxic for protists. In contrast, bacteria isolated from long time chronically infected patients (2-23 years, were less efficient in both resisting phages and killing protists. Moreover, chronic isolates showed reduced killing of wax moth larvae (Galleria mellonella probably due to weaker in vitro growth and protease expression. These results suggest that P. aeruginosa long-term adaptation to CF-lungs could trade off with its survival in aquatic environmental reservoirs in the presence of microbial enemies, while lowered virulence could reduce pathogen opportunities to infect insect vectors; factors that are both likely to result in poorer environmental transmission. From an applied perspective, phage therapy could be useful against chronic P. aeruginosa lung infections that are often characterized by multidrug resistance: chronic isolates were least resistant to phages and their poor growth will likely slow down the emergence of beneficial resistance mutations.

Abortion in woman caused by caprine Chlamydophila abortus (Chlamydia psittaci serovar 1).

Science.gov (United States)

Pospischil, A; Thoma, R; Hilbe, M; Grest, P; Gebbers, J-O

2002-02-09

On a farm housing cattle and goats an abortion storm occurred affecting 50% of the goats during the lambing season 2000/2001. In one of three investigated caprine abortions Chlamydophila abortus could be identified as aetiology. During this time a pregnant woman (pregnancy week 19/20) had contact with aborting goats. She developed a severe generalized infection and aborted. The placenta contained Chlamydophila abortus shown by immunohistochemistry and PCR. The aim of the present case report is to alert medical doctors about the potential zoonotic risk of ovine/caprine abortions.

Transport of Escherichia coli phage through saturated porous media considering managed aquifer recharge.

Science.gov (United States)

Zhang, Wenjing; Li, Shuo; Wang, Shuang; Lei, Liancheng; Yu, Xipeng; Ma, Tianyi

2018-03-01

Virus is one of the most potentially harmful microorganisms in groundwater. In this paper, the effects of hydrodynamic and hydrogeochemical conditions on the transportation of the colloidal virus considering managed aquifer recharge were systematically investigated. Escherichia coli phage, vB_EcoM-ep3, has a broad host range and was able to lyse pathogenic Escherichia coli. Bacteriophage with low risk to infect human has been found extensively in the groundwater environment, so it is considered as a representative model of groundwater viruses. Laboratory studies were carried out to analyze the transport of the Escherichia coli phage under varying conditions of pH, ionic strength, cation valence, flow rate, porous media, and phosphate buffer concentration. The results indicated that decreasing the pH will increase the adsorption of Escherichia coli phage. Increasing the ionic strength, either Na + or Ca 2+ , will form negative condition for the migration of Escherichia coli phage. A comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca 2+ than monovalent Na + . As the flow rate increases, the release of Escherichia coli phage increases and the retention of Escherichia coli phage in the aquifer medium reduces. Changes in porous media had a significant effect on Escherichia coli phage migration. With increase of phosphate buffer concentration, the suspension stability and migration ability of Escherichia coli phage are both increased. Based on laboratory-scale column experiments, a one-dimensional transport model was established to quantitatively describe the virus transport in saturated porous medium.

Study of the phage production efficiency in the bacteria lysis processes; Estudio del rendimiento en fagos para los procesos de lisis bacteriana

Energy Technology Data Exchange (ETDEWEB)

Vidania Munoz, R de; Garces, F; Davila, C A

1979-07-01

In this work we present a search for the best production conditions of {lambda}vir and{lambda} clear phages In E coli K12 and E coli C{sub 6}00 infected cells respectively. By keeping fixed some parameters of the process as the bacterial and phage generation times and the bacterial burst side, we have found that the lysis yield is strongly dependent on the multiplicity and in a lesser degree on the infection time. It appears from the experimental results that other variables are important, as infection efficiency and approach time from phages to bacteria. We will try to describe the lysis phenomenon by a numerical model on the bases of the se experimental results. (Author) 11 refs.

Immune TB Antibody Phage Display Library as a Tool To Study B Cell Immunity in TB Infections.

Science.gov (United States)

Hamidon, Nurul Hamizah; Suraiya, Siti; Sarmiento, Maria E; Acosta, Armando; Norazmi, Mohd Nor; Lim, Theam Soon

2018-03-01

B cells and in particular antibodies has always played second fiddle to cellular immunity in regard to tuberculosis (TB). However, recent studies has helped position humoral immunity especially antibodies back into the foray in relation to TB immunity. Therefore, the ability to correlate the natural antibody responses of infected individuals toward TB antigens would help strengthen this concept. Phage display is an intriguing approach that can be utilized to study antibody-mediated responses against a particular infection via harvesting the B cell repertoire from infected individuals. The development of disease-specific antibody libraries or immune libraries is useful to better understand antibody-mediated immune responses against specific disease antigens. This study describes the generation of an immune single-chain variable fragment (scFv) library derived from TB-infected individuals. The immune library with an estimated diversity of 10 9 independent clones was then applied for the identification of monoclonal antibodies against Mycobacterium tuberculosis α-crystalline as a model antigen. Biopanning of the library isolated three monoclonal antibodies with unique gene usage. This strengthens the role of antibodies in TB immunity in addition to the role played by cellular immunity. The developed library can be applied against other TB antigens and aid antibody-derived TB immunity studies in the future.

Recombinant phage probes for Listeria monocytogenes

Science.gov (United States)

Carnazza, S.; Gioffrè, G.; Felici, F.; Guglielmino, S.

2007-10-01

Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 104 cells ml-1. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

Detection of bacteriophage-infected cells of Lactococcus lactis using flow cytometry

DEFF Research Database (Denmark)

Michelsen, Ole; Cuesta-Dominguez, Álvaro; Albrektsen, Bjarne

2007-01-01

Bacteriophage infection in dairy fermentation constitutes a serious problem worldwide. We have studied bacteriophage infection in Lactococcus lactis by using the flow cytometer. The first effect of the infection of the bacterium is a change from cells in chains toward single cells. We interpret...... describe a new method for detection of phage infection in Lactococcus lactis dairy cultures. The method is based on flow cytometric detection of cells with low-density cell walls. The method allows fast and early detection of phage-infected bacteria, independently of which phage has infected the culture...

Current insights into phage biodiversity and biogeography.

Science.gov (United States)

Thurber, Rebecca Vega

2009-10-01

Phages exert tremendous ecological and evolutionary forces directly on their bacterial hosts. Phage induced cell lysis also indirectly contributes to organic and inorganic nutrient recycling. Phage abundance, diversity, and distribution are therefore important parameters in ecosystem function. The assumption that phage consortia are ubiquitous and homogenous across habitats (everything is everywhere) is currently being re-evaluated. New studies on phage biogeography have found that some phages are globally distributed while others are unique and perhaps endemic to specific environments. Furthermore, advances in technology have allowed scientists to conduct experiments aimed at analyzing phage consortia over temporal scales, and surprisingly have found reoccurring patterns. This review discusses currents in the field of phage ecology with particular focus on efforts to characterize phage diversity and biogeography across various spatial and temporal scales.

Abortion.

Science.gov (United States)

1993-05-01

The Alan Guttmacher Institute's State Reproductive Health Monitor "Legislative Proposals and Actions" provides US legislative information on abortion. The listing contains information on pending bills: the state, the identifying legislative number, the sponsor, the committee, the date the bill was introduced, a description of the bill, and when available the bill's status. The bills cover: 1) clinic licensing, e.g., requiring outpatient health care facilities in which abortions are performed, to have malpractice liability insurance; 2) comprehensive statues, which require parental notification before minor may obtain abortions, mandate abortion counseling to all women 24 hours before the abortion can be performed and prohibit disciplining or discharging a state employee for refusing to provide abortion counseling; 3) fetal personhood and rights, e.g. providing that life is vested in each person at fertilization; 4) fetal research and remains; 5) gender of fetus, which regulate abortions relative to sex selection in pregnancies; 6) harassment regulation; 7) informed consent and waiting periods detailing the risks and alternatives to abortion, and the 24-hour waiting period; 8) insurance coverage, e.g., eliminating language banning the coverage of abortions for state workers, and prohibiting disclosure by a health insurance carrier to the employer of a claimant that the claimant had a surgical abortion; 9) legality of abortion, urging Congress to reject he Freedom of Choice Act; 10) parental consent and notification; 11) postviability requirements; 12) public funding; 13) reporting requirements; 14) reproductive rights, and 15) spousal and paternal consent and notification.

Recombinant phage probes for Listeria monocytogenes

Energy Technology Data Exchange (ETDEWEB)

Carnazza, S; Gioffre, G; Felici, F; Guglielmino, S [Department of Microbiological, Genetic and Molecular Sciences, University of Messina, Messina (Italy)

2007-10-03

Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 10{sup 4} cells ml{sup -1}. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

Hobi-like pestivirus in aborted bovine fetuses.

Science.gov (United States)

Decaro, Nicola; Lucente, Maria Stella; Mari, Viviana; Sciarretta, Rossana; Pinto, Pierfrancesco; Buonavoglia, Domenico; Martella, Vito; Buonavoglia, Canio

2012-02-01

An outbreak of abortion affecting multiparous cows was associated with Hobi-like pestivirus infection. Viral RNA and antigens were detected in the tissues of two aborted fetuses. Molecular assays for other common abortogenic agents tested negative. At the genetic level, the Hobi-like pestivirus displayed the closest relatedness to Italian, Australian, and South American viruses, whereas it diverged from the prototype Thai isolate. These findings may have important implications for the pestivirus control/eradication programs in cattle herds.

[Abortion and rights. Legal thinking about abortion].

Science.gov (United States)

Perez Duarte, A E

1991-01-01

Analysis of abortion in Mexico from a juridical perspective requires recognition that Mexico as a national community participates in a double system of values. Politically it is defined as a liberal, democratic, and secular state, but culturally the Judeo-Christian ideology is dominant in all social strata. This duality complicates all juridical-penal decisions regarding abortion. Public opinion on abortion is influenced on the 1 hand by extremely conservative groups who condemn abortion as homicide, and on the other hand by groups who demand legislative reform in congruence with characteristics that define the state: an attitude of tolerance toward the different ideological-moral positions that coexist in the country. The discussion concerns the rights of women to voluntary maternity, protection of health, and to making their own decisions regarding their bodies vs. the rights of the fetus to life. The type of analysis is not objective, and conclusions depend on the ideology of the analyst. Other elements must be examined for an objective consideration of the social problem of abortion. For example, aspects related to maternal morbidity and mortality and the demographic, economic, and physical and mental health of the population would all seem to support the democratic juridical doctrine that sees the clandestine nature of abortion as the principal problem. It is also observed that the illegality of abortion does not guarantee its elimination. Desperate women will seek abortion under any circumstances. The illegality of abortion also impedes health and educational policies that would lower abortion mortality. There are various problems from a strictly juridical perspective. A correct definition of the term abortion is needed that would coincide with the medical definition. The discussion must be clearly centered on the protected juridical right and the definition of reproductive and health rights and rights to their own bodies of women. The experiences of other

Abortion - medical

Science.gov (United States)

Therapeutic medical abortion; Elective medical abortion; Induced abortion; Nonsurgical abortion ... A medical, or nonsurgical, abortion can be done within 7 weeks from the first day of the woman's last ...

Corruption of phage-display libraries by target-unrelated clones: Diagnosis and countermeasures

Science.gov (United States)

Thomas, William D.; Golomb, Miriam; Smith, George P.

2010-01-01

Phage display is used to discover peptides or proteins with a desired target property—most often, affinity for a target selector molecule. Libraries of phage clones displaying diverse surface peptides are subject to a selection process designed to enrich for the target behavior, and subsequently propagated to restore phage numbers. A recurrent problem is enrichment of clones, called target-unrelated phage (TUPs), that lack the target behavior. Many TUPs are propagation-related; they have mutations conferring a growth advantage, and are enriched during the propagations accompanying selection. Unlike other filamentous phage libraries, fd-tet-based libraries are relatively resistant to propagation-related TUP corruption. Their minus strand origin is disrupted by a large cassette that simultaneously confers resistance to tetracycline and imposes a rate-limiting growth defect that cannot be bypassed with simple mutations. Nonetheless, a new type of propagation-related TUP emerged in the output of in vivo selections from an fd-tet library. The founding clone had a complex rearrangement that restored the minus strand origin while retaining tetracycline resistance. The rearrangement involved two recombination events, one with a contaminant having a wild-type minus strand origin. The founder’s infectivity advantage spread by simple recombination to clones displaying different peptides. We propose measures for minimizing TUP corruption. PMID:20692225

HostPhinder: A Phage Host Prediction Tool

Directory of Open Access Journals (Sweden)

Julia Villarroel

2016-05-01

Full Text Available The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2].

Induced abortion among Brazilian female sex workers: a qualitative study.

Science.gov (United States)

Madeiro, Alberto Pereira; Diniz, Debora

2015-02-01

Prostitutes are vulnerable to unplanned pregnancies and abortions. In Brazil, abortion is a crime and there is no data about unsafe abortions for this population. The study describes how prostitutes perform illegal abortions and the health consequences thereof. Semi-structured interviews with 39 prostitutes from three cities in Brazil with previous induced abortion experience were conducted. Sixty-six abortions, with between one and eight occurrences per woman, were recorded. The majority of the cases resulted from sexual activity with clients. The inconsistent use of condoms with regular clients and the consumption of alcohol during work were indicated as the main causes of unplanned pregnancies. The main method to perform abortion was the intravaginal and oral use of misoprostol, acquired in pharmacies or on the black market. Invasive measures were less frequently reported, however with more serious health complications. The fear of complaint to the police meant that most women do not inform the health team regarding induced abortion. The majority of prostitutes aborted with the use of illegally-acquired misoprostol, ending abortion in a public hospital with infection and hemorrhagic complications. The data indicate the need for a public policy focusing on the reproductive health of prostitutes.

Abundant and diverse clustered regularly interspaced short palindromic repeat spacers in Clostridium difficile strains and prophages target multiple phage types within this pathogen.

Science.gov (United States)

Hargreaves, Katherine R; Flores, Cesar O; Lawley, Trevor D; Clokie, Martha R J

2014-08-26

Clostridium difficile is an important human-pathogenic bacterium causing antibiotic-associated nosocomial infections worldwide. Mobile genetic elements and bacteriophages have helped shape C. difficile genome evolution. In many bacteria, phage infection may be controlled by a form of bacterial immunity called the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system. This uses acquired short nucleotide sequences (spacers) to target homologous sequences (protospacers) in phage genomes. C. difficile carries multiple CRISPR arrays, and in this paper we examine the relationships between the host- and phage-carried elements of the system. We detected multiple matches between spacers and regions in 31 C. difficile phage and prophage genomes. A subset of the spacers was located in prophage-carried CRISPR arrays. The CRISPR spacer profiles generated suggest that related phages would have similar host ranges. Furthermore, we show that C. difficile strains of the same ribotype could either have similar or divergent CRISPR contents. Both synonymous and nonsynonymous mutations in the protospacer sequences were identified, as well as differences in the protospacer adjacent motif (PAM), which could explain how phages escape this system. This paper illustrates how the distribution and diversity of CRISPR spacers in C. difficile, and its prophages, could modulate phage predation for this pathogen and impact upon its evolution and pathogenicity. Clostridium difficile is a significant bacterial human pathogen which undergoes continual genome evolution, resulting in the emergence of new virulent strains. Phages are major facilitators of genome evolution in other bacterial species, and we use sequence analysis-based approaches in order to examine whether the CRISPR/Cas system could control these interactions across divergent C. difficile strains. The presence of spacer sequences in prophages that are homologous to phage genomes raises an

Are Phage Lytic Proteins the Secret Weapon To Kill Staphylococcus aureus?

Science.gov (United States)

Gutiérrez, Diana; Fernández, Lucía; Rodríguez, Ana; García, Pilar

2018-01-23

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most threatening microorganisms for global human health. The current strategies to reduce the impact of S. aureus include a restrictive control of worldwide antibiotic use, prophylactic measures to hinder contamination, and the search for novel antimicrobials to treat human and animal infections caused by this bacterium. The last strategy is currently the focus of considerable research. In this regard, phage lytic proteins (endolysins and virion-associated peptidoglycan hydrolases [VAPGHs]) have been proposed as suitable candidates. Indeed, these proteins display narrow-spectrum antimicrobial activity and a virtual lack of bacterial-resistance development. Additionally, the therapeutic use of phage lytic proteins in S. aureus animal infection models is yielding promising results, showing good efficacy without apparent side effects. Nonetheless, human clinical trials are still in progress, and data are not available yet. This minireview also analyzes the main obstacles for introducing phage lytic proteins as human therapeutics against S. aureus infections. Besides the common technological problems derived from large-scale production of therapeutic proteins, a major setback is the lack of a proper legal framework regulating their use. In that sense, the relevant health authorities should urgently have a timely discussion about these new antimicrobials. On the other hand, the research community should provide data to dispel any doubts regarding their efficacy and safety. Overall, the appropriate scientific data and regulatory framework will encourage pharmaceutical companies to invest in these promising antimicrobials. Copyright © 2018 Gutiérrez et al.

Induced Abortion

Science.gov (United States)

... Education & Events Advocacy For Patients About ACOG Induced Abortion Home For Patients Search FAQs Induced Abortion Page ... Induced Abortion FAQ043, May 2015 PDF Format Induced Abortion Special Procedures What is an induced abortion? What ...

Assembling filamentous phage occlude pIV channels.

Science.gov (United States)

Marciano, D K; Russel, M; Simon, S M

2001-07-31

Filamentous phage f1 is exported from its Escherichia coli host without killing the bacterial cell. Phage-encoded protein pIV, which is required for phage assembly and secretion, forms large highly conductive channels in the outer membrane of E. coli. It has been proposed that the phage are extruded across the bacterial outer membrane through pIV channels. To test this prediction, we developed an in vivo assay by using a mutant pIV that functions in phage export but whose channel opens in the absence of phage extrusion. In E. coli lacking its native maltooligosacharride transporter LamB, this pIV variant allowed oligosaccharide transport across the outer membrane. This entry of oligosaccharide was decreased by phage production and still further decreased by production of phage that cannot be released from the cell surface. Thus, exiting phage block the pIV-dependent entry of oligosaccharide, suggesting that phage occupy the lumen of pIV channels. This study provides the first evidence, to our knowledge, for viral exit through a large aqueous channel.

Detection of porcine circovirus genotypes 2a and 2b in aborted foetuses from infected swine herds in the State of São Paulo, Brazil

Directory of Open Access Journals (Sweden)

de Castro Alessandra MMG

2012-05-01

Full Text Available Abstract Background Porcine circovirus type 2 (PCV2 has been associated with several disease complexes, including reproductive failure. The aim of this study was to identify the subtypes of PCV2 that are associated with reproductive failure in pigs from the State of São Paulo, Brazil and to investigate co-infections with other infectious organisms. Findings Samples of 168 aborted foetuses or mummified foetuses from five farrow-to-finish swine farms known to be infected with PCV2 and located in the State of São Paulo were tested for PCV2 by polymerase chain reaction (PCR. Positive samples were additionally tested for porcine parvovirus (PPV, Leptospira spp. and Brucella spp. by PCR. PCV2 was detected in 18 of the samples (10.7%. PPV, Brucella spp. and Leptospira spp were found in 2, 10 and 0 cases, respectively. Eleven PCV2 strains were sequenced and determined to be either genotype 2a (n = 1 or 2b (n = 10. Conclusions The findings indicate that the frequency of PCV2 infections in aborted porcine foetuses from the State of São Paulo is rather low (10.7% and that co-infection with other pathogens is common and may be involved in PCV2 associated reproductive failure. No repeatable, characteristic amino acid motifs for regions of the PCV2 capsid protein seemed to be associated with abortion in sows.

Q-feber som årsag til spontan abort

DEFF Research Database (Denmark)

Nielsen, Stine Yde; Mølbak, Kåre; Hjøllund, Niels Henrik

2011-01-01

the first weeks of her pregnancy, she handled birth by-products from cows with Q-fever. The Q-fever titres revealed that she was most likely infected in very early pregnancy. According to the literature, infection in the first trimester constitutes a specific risk of spontaneous abortion....

Temperate Streptococcus thermophilus phages expressing superinfection exclusion proteins of the Ltp type

Directory of Open Access Journals (Sweden)

Yahya eAli

2014-03-01

Full Text Available Lipoprotein Ltp encoded by temperate Streptococcus thermophilus phage TP-J34 is the prototype of the wide-spread family of host cell surface-exposed lipoproteins involved in superinfection exclusion. When screening for other S. thermophilus phages expressing this type of lipoprotein, three temperate phages - TP-EW, TP-DSM20617 and TP-778 - were isolated. In this communication we present the total nucleotide sequences of TP-J34 and TP-778L. For TP-EW, a phage almost identical to TP-J34, besides the ltp gene only the two regions of deviation from TP-J34 DNA were analyzed: the gene encoding the tail protein causing an assembly defect in TP-J34 and the gene encoding the lysin, which in TP-EW contains an intron. For TP-DSM20617 only the sequence of the lysogeny module containing the ltp gene was determined. The region showed high homology to the same region of TP-778. For TP-778 we could show that absence of the attR region resulted in aberrant excision of phage DNA. The amino acid sequence of mature LtpTP-EW was shown to be identical to that of mature LtpTP-J34, whereas the amino acid sequence of mature LtpTP-778 was shown to differ from mature LtpTP-J34 in eight amino acid positions. LtpTP-DSM20617 was shown to differ from LtpTP-778 in just one amino acid position. In contrast to LtpTP-J34, LtpTP-778 did not affect infection of lactococcal phage P008 instead increased activity against phage P001 was noticed.

Vaccines against a Major Cause of Abortion in Cattle, Neospora caninum Infection

Directory of Open Access Journals (Sweden)

Andrew Hemphill

2011-09-01

Full Text Available Neosporosis, caused by the apicomplexan parasite Neospora caninum, represents one of the economically most important causes of abortion in cattle. During pregnancy, the parasite infects the placental tissue and the fetus, which can lead to stillbirth, abortion, or birth of weak calves. Alternatively, calves are born without clinical symptoms, but they can carry over the parasite to the next generation. In addition, N. caninum causes neuromuscular disease in dogs. The economic importance of neosporosis has prompted researchers to invest in the development of measures to prevent infection of cattle by vaccination. A good vaccine must stimulate protective cellular immune responses as well as antibody responses at mucosal sites and, systemically, must activate T-helper cells to produce relevant cytokines, and must elicit specific antibodies that aid in limiting parasite proliferation, e.g., by interference with host cell invasion, activation of complement, and/or opsonization of parasites to have them killed by macrophages. Different types of vaccines have been investigated, either in bovines or in the mouse model. These include live vaccines such as naturally less virulent isolates of N. caninum, attenuated strains generated by irradiation or chemical means, or genetically modified transgenic strains. Live vaccines were shown to be very effective; however, there are serious disadvantages in terms of safety, costs of production, and stability of the final product. Subunit vaccines have been intensively studied, as they would have clear advantages such as reduced costs in production, processing and storage, increased stability and shelf life. The parasite antigens involved in adhesion and invasion of host cells, such as surface constituents, microneme-, rhoptry- and dense granule-components represent interesting targets. Subunit vaccines have been applied as bacterially expressed recombinant antigens or as DNA vaccines. Besides monovalent vaccines

Pseudomonas aeruginosa adaptation to lungs of cystic fibrosis patients leads to lowered resistance to phage and protist enemies

DEFF Research Database (Denmark)

Friman, Ville-Petri; Ghoul, Melanie; Molin, Søren

2013-01-01

) patients affects its survival in the presence of natural phage (14/1, ΦKZ, PNM and PT7) and protist (Tetrahymena thermophila and Acanthamoebae polyphaga) enemies. We found that most of the bacteria isolated from relatively recently intermittently colonised patients (1-25 months), were innately phage......-resistant and highly toxic for protists. In contrast, bacteria isolated from long time chronically infected patients (2-23 years), were less efficient in both resisting phages and killing protists. Moreover, chronic isolates showed reduced killing of wax moth larvae (Galleria mellonella) probably due to weaker...

Chlamydia pecorum: fetal and placental lesions in sporadic caprine abortion.

Science.gov (United States)

Giannitti, Federico; Anderson, Mark; Miller, Myrna; Rowe, Joan; Sverlow, Karen; Vasquez, Marce; Cantón, Germán

2016-03-01

Chlamydial abortion in small ruminants is usually associated with Chlamydia abortus infection. Although Chlamydia pecorum has been detected in aborted ruminants and epidemiological data suggests that C. pecorum is abortigenic in these species, published descriptions of lesions in fetuses are lacking. This work describes fetoplacental lesions in a caprine abortion with C. pecorum infection, and further supports the abortigenic role of C. pecorum in ruminants. A 16-month-old Boer goat aborted twin fetuses at ~130 days of gestation. Both fetuses (A and B) and the placenta of fetus A were submitted for postmortem examination and diagnostic workup. At autopsy, the fetuses had moderate anasarca, intermuscular edema in the hindquarters (A), and brachygnathia and palatoschisis (B). In the placenta, the cotyledons were covered by yellow fibrinosuppurative exudate that extended into the adjacent intercotyledonary areas. Histologically, there was severe suppurative and necrotizing placentitis with vasculitis (arteriolitis) and thrombosis, multifocal lymphohistiocytic and neutrophilic hepatitis (A), and fibrinosuppurative enteritis in both fetuses. Chlamydia antigen was detected in the placenta by the direct fluorescent antibody test and in fetal intestines by immunohistochemistry. Nested polymerase chain reaction of DNA extracted from formalin-fixed, paraffin-embedded sections of placenta and intestine amplified 400 bp of the Chlamydia 16S rRNA gene that was sequenced and found to be 99% identical to C. pecorum by BLAST analysis. Other known abortigenic infectious agents were ruled out by specific testing. It is concluded that C. pecorum infection is associated with fetoplacental lesions and sporadic abortion in goats. © 2015 The Author(s).

Efficacy and Safety of a Bovine-Associated Staphylococcus aureus Phage Cocktail in a Murine Model of Mastitis

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Koen Breyne

2017-11-01

Full Text Available Overuse of antibiotics is a major problem in the treatment of bovine mastitis, and antibiotic treatment is frequently non-curative, thus alternative treatments are necessary. The primary aim of this study was to evaluate the efficacy of a purified phage cocktail for treatment of bovine Staphylococcus aureus mastitis in a well-defined mouse model. Candidate phages were selected based on their in vitro performance and subsequently processed into an optimally composed phage cocktail. The highest scoring phages were further tested for efficacy and resistance suppression in broth and raw milk, with and without supplemental IgG. As these in vitro results displayed significant decreases in CFU, the cocktail was purified for testing in vivo. Lactating mice were intramammarily inoculated with S. aureus N305 (ATCC 29740, a clinical bovine mastitis isolate commonly used for experimental infection of dairy cows. The phage cocktail was applied via the same route 4 h post-inoculation. Treated mammary glands were graded for gross pathological appearance and excised for bacterial and phage load quantification as well as histopathology. Observation of gross macroscopic and histopathological changes and CFU quantification demonstrated that the phage cocktail treatment significantly improved mastitis pathology and decreased bacterial counts. Phage PFU quantification indicated that the tested phage cocktail treatment was able to maintain high intramammary phage titers without spreading systemically. The in vivo results complement the in vitro data and support our concept of phage therapy as an innovative alternative or supplementation therapy to antibiotics for the treatment of bovine mastitis.

Efficacy and Safety of a Bovine-Associated Staphylococcus aureus Phage Cocktail in a Murine Model of Mastitis.

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Breyne, Koen; Honaker, Ryan W; Hobbs, Zachary; Richter, Manuela; Żaczek, Maciej; Spangler, Taylor; Steenbrugge, Jonas; Lu, Rebecca; Kinkhabwala, Anika; Marchon, Bruno; Meyer, Evelyne; Mokres, Lucia

2017-01-01

Overuse of antibiotics is a major problem in the treatment of bovine mastitis, and antibiotic treatment is frequently non-curative, thus alternative treatments are necessary. The primary aim of this study was to evaluate the efficacy of a purified phage cocktail for treatment of bovine Staphylococcus aureus mastitis in a well-defined mouse model. Candidate phages were selected based on their in vitro performance and subsequently processed into an optimally composed phage cocktail. The highest scoring phages were further tested for efficacy and resistance suppression in broth and raw milk, with and without supplemental IgG. As these in vitro results displayed significant decreases in CFU, the cocktail was purified for testing in vivo . Lactating mice were intramammarily inoculated with S. aureus N305 (ATCC 29740), a clinical bovine mastitis isolate commonly used for experimental infection of dairy cows. The phage cocktail was applied via the same route 4 h post-inoculation. Treated mammary glands were graded for gross pathological appearance and excised for bacterial and phage load quantification as well as histopathology. Observation of gross macroscopic and histopathological changes and CFU quantification demonstrated that the phage cocktail treatment significantly improved mastitis pathology and decreased bacterial counts. Phage PFU quantification indicated that the tested phage cocktail treatment was able to maintain high intramammary phage titers without spreading systemically. The in vivo results complement the in vitro data and support our concept of phage therapy as an innovative alternative or supplementation therapy to antibiotics for the treatment of bovine mastitis.

Pyocin-sensitivity testing as a method of typing Pseudomonas aeruginosa: use of "phage-free" preparations of pyocin.

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Rampling, A; Whitby, J L; Wildy, P

1975-11-01

A method for pyocin-sensitivity typing by means of "phage-free" preparations of pyocin is described. The method was tested on 227 isolates of P. aeruginosa, collected from 34 different foci of infection in hospitals in the British Isles and the results were compared with those for combined serological and phage typing of all strains and pyocin production of 105 of the isolates. It is concluded that pyocin-sensitivity typing is a simple and reliable method giving a high degree of discrimination, comparable to that of combined serological and phage typing, and it is suitable for use in routine hospital laboratories.

Basics of Antibody Phage Display Technology.

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Ledsgaard, Line; Kilstrup, Mogens; Karatt-Vellatt, Aneesh; McCafferty, John; Laustsen, Andreas H

2018-06-09

Antibody discovery has become increasingly important in almost all areas of modern medicine. Different antibody discovery approaches exist, but one that has gained increasing interest in the field of toxinology and antivenom research is phage display technology. In this review, the lifecycle of the M13 phage and the basics of phage display technology are presented together with important factors influencing the success rates of phage display experiments. Moreover, the pros and cons of different antigen display methods and the use of naïve versus immunized phage display antibody libraries is discussed, and selected examples from the field of antivenom research are highlighted. This review thus provides in-depth knowledge on the principles and use of phage display technology with a special focus on discovery of antibodies that target animal toxins.

Induced abortion among Brazilian female sex workers: a qualitative study

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Alberto Pereira Madeiro

2015-02-01

Full Text Available Prostitutes are vulnerable to unplanned pregnancies and abortions. In Brazil, abortion is a crime and there is no data about unsafe abortions for this population. The study describes how prostitutes perform illegal abortions and the health consequences thereof. Semi-structured interviews with 39 prostitutes from three cities in Brazil with previous induced abortion experience were conducted. Sixty-six abortions, with between one and eight occurrences per woman, were recorded. The majority of the cases resulted from sexual activity with clients. The inconsistent use of condoms with regular clients and the consumption of alcohol during work were indicated as the main causes of unplanned pregnancies. The main method to perform abortion was the intravaginal and oral use of misoprostol, acquired in pharmacies or on the black market. Invasive measures were less frequently reported, however with more serious health complications. The fear of complaint to the police meant that most women do not inform the health team regarding induced abortion. The majority of prostitutes aborted with the use of illegally-acquired misoprostol, ending abortion in a public hospital with infection and hemorrhagic complications. The data indicate the need for a public policy focusing on the reproductive health of prostitutes.

Demand for abortion and post abortion care in Ibadan, Nigeria.

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Awoyemi, Bosede O; Novignon, Jacob

2014-01-01

While induced abortion is considered to be illegal and socially unacceptable in Nigeria, it is still practiced by many women in the country. Poor family planning and unsafe abortion practices have daunting effects on maternal health. For instance, Nigeria is on the verge of not meeting the Millennium development goals on maternal health due to high maternal mortality ratio, estimated to be about 630 maternal deaths per 100,000 live births. Recent evidences have shown that a major factor in this trend is the high incidence of abortion in the country. The objective of this paper is, therefore, to investigate the factors determining the demand for abortion and post-abortion care in Ibadan city of Nigeria. The study employed data from a hospital-based/exploratory survey carried out between March to September 2010. Closed ended questionnaires were administered to a sample of 384 women of reproductive age from three hospitals within the Ibadan metropolis in South West Nigeria. However, only 308 valid responses were received and analysed. A probit model was fitted to determine the socioeconomic factors that influence demand for abortion and post-abortion care. The results showed that 62% of respondents demanded for abortion while 52.3% of those that demanded for abortion received post-abortion care. The findings again showed that income was a significant determinant of abortion and post-abortion care demand. Women with higher income were more likely to demand abortion and post-abortion care. Married women were found to be less likely to demand for abortion and post-abortion care. Older women were significantly less likely to demand for abortion and post-abortion care. Mothers' education was only statistically significant in determining abortion demand but not post-abortion care demand. The findings suggest that while abortion is illegal in Nigeria, some women in the Ibadan city do abort unwanted pregnancies. The consequence of this in the absence of proper post-abortion

Demand for abortion and post abortion care in Ibadan, Nigeria

Science.gov (United States)

2014-01-01

Background While induced abortion is considered to be illegal and socially unacceptable in Nigeria, it is still practiced by many women in the country. Poor family planning and unsafe abortion practices have daunting effects on maternal health. For instance, Nigeria is on the verge of not meeting the Millennium development goals on maternal health due to high maternal mortality ratio, estimated to be about 630 maternal deaths per 100,000 live births. Recent evidences have shown that a major factor in this trend is the high incidence of abortion in the country. The objective of this paper is, therefore, to investigate the factors determining the demand for abortion and post-abortion care in Ibadan city of Nigeria. Methods The study employed data from a hospital-based/exploratory survey carried out between March to September 2010. Closed ended questionnaires were administered to a sample of 384 women of reproductive age from three hospitals within the Ibadan metropolis in South West Nigeria. However, only 308 valid responses were received and analysed. A probit model was fitted to determine the socioeconomic factors that influence demand for abortion and post-abortion care. Results The results showed that 62% of respondents demanded for abortion while 52.3% of those that demanded for abortion received post-abortion care. The findings again showed that income was a significant determinant of abortion and post-abortion care demand. Women with higher income were more likely to demand abortion and post-abortion care. Married women were found to be less likely to demand for abortion and post-abortion care. Older women were significantly less likely to demand for abortion and post-abortion care. Mothers’ education was only statistically significant in determining abortion demand but not post-abortion care demand. Conclusion The findings suggest that while abortion is illegal in Nigeria, some women in the Ibadan city do abort unwanted pregnancies. The consequence of this

[Peptide phage display in biotechnology and biomedicine].

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Kuzmicheva, G A; Belyavskaya, V A

2016-07-01

To date peptide phage display is one of the most common combinatorial methods used for identifying specific peptide ligands. Phage display peptide libraries containing billions different clones successfully used for selection of ligands with high affinity and selectivity toward wide range of targets including individual proteins, bacteria, viruses, spores, different kind of cancer cells and variety of nonorganic targets (metals, alloys, semiconductors etc.) Success of using filamentous phage in phage display technologies relays on the robustness of phage particles and a possibility to genetically modify its DNA to construct new phage variants with novel properties. In this review we are discussing characteristics of the most known non-commercial peptide phage display libraries of different formats (landscape libraries in particular) and their successful applications in several fields of biotechnology and biomedicine: discovery of peptides with diagnostic values against different pathogens, discovery and using of peptides recognizing cancer cells, trends in using of phage display technologies in human interactome studies, application of phage display technologies in construction of novel nano materials.

Membrane insertion and assembly of epitope-tagged gp9 at the tip of the M13 phage

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Kuhn Andreas

2011-09-01

Full Text Available Abstract Background Filamentous M13 phage extrude from infected Escherichia coli with a tip structure composed of gp7 and gp9. This tip structure is extended by the assembly of the filament composed of the major coat protein gp8. Finally, gp3 and gp6 terminate the phage structure at the proximal end. Up to now, gp3 has been the primary tool for phage display technology. However, gp7, gp8 and gp9 could also be used for phage display and these phage particles should bind to two different or more surfaces when the modified coat proteins are combined. Therefore, we tested here if the amino-terminal end of gp9 can be modified and whether the modified portion is exposed and detectable on the M13 phage particles. Results The amino-terminal region of gp9 was modified by inserting short sequences that encode antigenic epitopes. We show here that the modified gp9 proteins correctly integrate into the membrane using the membrane insertase YidC exposing the modified epitope into the periplasm. The proteins are then efficiently assembled onto the phage particles. Also extensions up to 36 amino acid residues at the amino-terminal end of gp9 did not interfere with membrane integration and phage assembly. The exposure of the antigenic tags on the phage was visualised with immunogold labelling by electron microscopy and verified by dot blotting with antibodies to the tags. Conclusions Our results suggest that gp9 at the phage tip is suitable for the phage display technology. The modified gp9 can be supplied in trans from a plasmid and fully complements M13 phage with an amber mutation in gene 9. The modified phage tip is very well accessible to antibodies.

Dual host specificity of phage SP6 is facilitated by tailspike rotation

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Tu, Jiagang [Department of Pathology and Laboratory Medicine, McGovern Medical School at UTHealth, Houston, TX 77030 (United States); Park, Taehyun [Center for Infectious Disease, Department of Molecular Biosciences, Institute for Cell and Molecular Biology, University of Texas at Austin, Austin, TX 78712 (United States); Morado, Dustin R. [Department of Pathology and Laboratory Medicine, McGovern Medical School at UTHealth, Houston, TX 77030 (United States); Hughes, Kelly T. [Department of Biology, University of Utah, Salt Lake City, UT 84112 (United States); Molineux, Ian J., E-mail: molineux@austin.utexas.edu [Center for Infectious Disease, Department of Molecular Biosciences, Institute for Cell and Molecular Biology, University of Texas at Austin, Austin, TX 78712 (United States); Liu, Jun, E-mail: Jun.Liu.1@uth.tmc.edu [Department of Pathology and Laboratory Medicine, McGovern Medical School at UTHealth, Houston, TX 77030 (United States)

2017-07-15

Bacteriophage SP6 exhibits dual-host adsorption specificity. The SP6 tailspikes are recognized as important in host range determination but the mechanisms underlying dual host specificity are unknown. Cryo-electron tomography and sub-tomogram classification were used to analyze the SP6 virion with a particular focus on the interaction of tailspikes with host membranes. The SP6 tail is surrounded by six V-shaped structures that interconnect in forming a hand-over-hand hexameric garland. Each V-shaped structure consists of two trimeric tailspike proteins: gp46 and gp47, connected through the adaptor protein gp37. SP6 infection of Salmonella enterica serovars Typhimurium and Newport results in distinguishable changes in tailspike orientation, providing the first direct demonstration how tailspikes can confer dual host adsorption specificity. SP6 also infects S. Typhimurium strains lacking O antigen; in these infections tailspikes have no apparent specific role and the phage tail must therefore interact with a distinct host receptor to allow infection. - Highlights: •Cryo-electron tomography reveals the structural basis for dual host specificity. •Sub-tomogram classification reveals distinct orientations of the tailspikes during infection of different hosts. •Tailspike-adaptor modules rotate as they bind different O antigens. •In the absence of any O antigen, tailspikes bind weakly and without specificity to LPS. •Interaction of the phage tail with LPS is essential for infection.

Abortion - surgical

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Suction curettage; Surgical abortion; Elective abortion - surgical; Therapeutic abortion - surgical ... Surgical abortion involves dilating the opening to the uterus (cervix) and placing a small suction tube into the uterus. ...

Bacteria between protists and phages: from antipredation strategies to the evolution of pathogenicity.

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Brüssow, Harald

2007-08-01

Bacteriophages and protists are major causes of bacterial mortality. Genomics suggests that phages evolved well before eukaryotic protists. Bacteria were thus initially only confronted with phage predators. When protists evolved, bacteria were caught between two types of predators. One successful antigrazing strategy of bacteria was the elaboration of toxins that would kill the grazer. The released cell content would feed bystander bacteria. I suggest here that, to fight grazing protists, bacteria teamed up with those phage predators that concluded at least a temporary truce with them in the form of lysogeny. Lysogeny was perhaps initially a resource management strategy of phages that could not maintain infection chains. Subsequently, lysogeny might have evolved into a bacterium-prophage coalition attacking protists, which became a food source for them. When protists evolved into multicellular animals, the lysogenic bacteria tracked their evolving food source. This hypothesis could explain why a frequent scheme of bacterial pathogenicity is the survival in phagocytes, why a significant fraction of bacterial pathogens have prophage-encoded virulence genes, and why some virulence factors of animal pathogens are active against unicellular eukaryotes. Bacterial pathogenicity might thus be one playing option of the stone-scissor-paper game played between phages-bacteria-protists, with humans getting into the crossfire.

Corruption of phage display libraries by target-unrelated clones: diagnosis and countermeasures.

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Thomas, William D; Golomb, Miriam; Smith, George P

2010-12-15

Phage display is used to discover peptides or proteins with a desired target property-most often, affinity for a target selector molecule. Libraries of phage clones displaying diverse surface peptides are subject to a selection process designed to enrich for the target behavior and subsequently propagated to restore phage numbers. A recurrent problem is enrichment of clones, called target-unrelated phages or peptides (TUPs), that lack the target behavior. Many TUPs are propagation related; they have mutations conferring a growth advantage and are enriched during the propagations accompanying selection. Unlike other filamentous phage libraries, fd-tet-based libraries are relatively resistant to propagation-related TUP corruption. Their minus-strand origin is disrupted by a large cassette that simultaneously confers resistance to tetracycline and imposes a rate-limiting growth defect that cannot be bypassed with simple mutations. Nonetheless, a new type of propagation-related TUP emerged in the output of in vivo selections from an fd-tet library. The founding clone had a complex rearrangement that restored the minus-strand origin while retaining tetracycline resistance. The rearrangement involved two recombination events, one with a contaminant having a wild-type minus-strand origin. The founder's infectivity advantage spread by simple recombination to clones displaying different peptides. We propose measures for minimizing TUP corruption. Copyright © 2010 Elsevier Inc. All rights reserved.

MVP: a microbe-phage interaction database.

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Gao, Na L; Zhang, Chengwei; Zhang, Zhanbing; Hu, Songnian; Lercher, Martin J; Zhao, Xing-Ming; Bork, Peer; Liu, Zhi; Chen, Wei-Hua

2018-01-04

Phages invade microbes, accomplish host lysis and are of vital importance in shaping the community structure of environmental microbiota. More importantly, most phages have very specific hosts; they are thus ideal tools to manipulate environmental microbiota at species-resolution. The main purpose of MVP (Microbe Versus Phage) is to provide a comprehensive catalog of phage-microbe interactions and assist users to select phage(s) that can target (and potentially to manipulate) specific microbes of interest. We first collected 50 782 viral sequences from various sources and clustered them into 33 097 unique viral clusters based on sequence similarity. We then identified 26 572 interactions between 18 608 viral clusters and 9245 prokaryotes (i.e. bacteria and archaea); we established these interactions based on 30 321 evidence entries that we collected from published datasets, public databases and re-analysis of genomic and metagenomic sequences. Based on these interactions, we calculated the host range for each of the phage clusters and accordingly grouped them into subgroups such as 'species-', 'genus-' and 'family-' specific phage clusters. MVP is equipped with a modern, responsive and intuitive interface, and is freely available at: http://mvp.medgenius.info. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Prevalence of parvovirus B19 specific antibody in pregnant women with spontaneous abortion.

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Rahbar, Nahid; Vali Zadeh, Saeid; Ghorbani, Raheb; Kheradmand, Pegah

2015-01-01

Human parvovirus B19 is a very common viral infection especially in school-aged children. The infection during pregnancy can affect the fetus due to lack of mother's immunity. Although, there is still no evidence of fetal teratogenic effects with parvovirus B19, but non-immune fetal hydrops and abortion may be caused by vertical transmission of the virus during pregnancy. This study was aimed to assess the prevalence of parvovirus B19-specific antibody (IgM) in pregnant women who had a spontaneous abortion. This cross-sectional study was carried out in all pregnant women who referred due to a spontaneous abortion. All demographic information such as age, occupation, and gestational age, last history of abortion, gravity, and presence of children below the age of six was recorded and a blood sample was provided for all the women. Then, the blood samples were tested to assay parvovirus B19-specific antibody (IgM) by EuroImmune ELISA kit. Among 94 pregnant women with the mean age of 28.4 years who had a spontaneous abortion, parvovirus B19 specific antibody (IgM) was detected in 17 participants (18.1%). Meanwhile, 14 women (14.9%) were suspected for presence of the antibody in their blood sample. There was no significant difference between the presence of antibody and age of pregnant women, occupation, gestational age, number of previous abortion, presence of children below the age of six and number of pregnancy. These findings revealed that a high percentage of pregnant women are probably non-immune against parvovirus B19, and also there might be a number of spontaneous abortions in which parvovirus infection caused fetal death.  However, more studies are needed to prove the absolute role of parvovirus B19 in these abortions.

Molecular insights on the recognition of a Lactococcus lactis cell wall pellicle by the phage 1358 receptor binding protein.

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Farenc, Carine; Spinelli, Silvia; Vinogradov, Evgeny; Tremblay, Denise; Blangy, Stéphanie; Sadovskaya, Irina; Moineau, Sylvain; Cambillau, Christian

2014-06-01

The Gram-positive bacterium Lactococcus lactis is used for the production of cheeses and other fermented dairy products. Accidental infection of L. lactis cells by virulent lactococcal tailed phages is one of the major risks of fermentation failures in industrial dairy factories. Lactococcal phage 1358 possesses a host range limited to a few L. lactis strains and strong genomic similarities to Listeria phages. We report here the X-ray structures of phage 1358 receptor binding protein (RBP) in complex with monosaccharides. Each monomer of its trimeric RBP is formed of two domains: a "shoulder" domain linking the RBP to the rest of the phage and a jelly roll fold "head/host recognition" domain. This domain harbors a saccharide binding crevice located in the middle of a monomer. Crystal structures identified two sites at the RBP surface, ∼8 Å from each other, one accommodating a GlcNAc monosaccharide and the other accommodating a GlcNAc or a glucose 1-phosphate (Glc1P) monosaccharide. GlcNAc and GlcNAc1P are components of the polysaccharide pellicle that we identified at the cell surface of L. lactis SMQ-388, the host of phage 1358. We therefore modeled a galactofuranose (Galf) sugar bridging the two GlcNAc saccharides, suggesting that the trisaccharidic motif GlcNAc-Galf-GlcNAc (or Glc1P) might be common to receptors of genetically distinct lactococcal phages p2, TP091-1, and 1358. Strain specificity might therefore be elicited by steric clashes induced by the remaining components of the pellicle hexasaccharide. Taken together, these results provide a first insight into the molecular mechanism of host receptor recognition by lactococcal phages. Siphophages infecting the Gram-positive bacterium Lactococcus lactis are sources of milk fermentation failures in the dairy industry. We report here the structure of the pellicle polysaccharide from L. lactis SMQ-388, the specific host strain of phage 1358. We determined the X-ray structures of the lytic lactococcal phage

Portrait of a viral infection: The infection cycle of Vibrio vulnificus phage VvAW1 visualized through plaque assay, electron microscopy, and proteomics

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Clah, K. E. Y.; Nigro, O. D.; Miranda, J.; Schvarcz, C.; Culley, A.; Saito, M. A.; Steward, G.

2016-02-01

The bacterium Vibrio vulnificus is an opportunistic human pathogen that thrives in warm brackish waters. Viral infection is one of several mechanisms influencing the population dynamics of this bacterium in the natural environment. V. vulnificus-specific viruses have been isolated; however, the details of their infection cycle have not been reported. As a result, our current understanding of the interaction between the bacterium and its viruses in the environment is limited. To better understand the infection process, a strain of V. vulnificus (V93D1V) and its bacteriophage, Vibrio phage VvAW1, were isolated from the estuarine waters of the Ala Wai Canal, HI. A time-series infection experiment was conducted with the virus-host pair in which samples were collected every ten minutes for eighty minutes post-infection for analysis by plaque assay, electron microscopy, and proteomics. Using electron microscopy, visibly infected bacteria were observed forty minutes after the introduction of the virus, signaling the end of the eclipse period. The peak of infection occurred at seventy minutes with an average viral load of 78 viruses per bacterium. The percentage of visibly infected bacteria reached a maximum just prior to a rise in free viruses in the culture, indicating the end of the latent period. The percentage of infected cells that lysed was low and there was little effect on the bacterial population growth rate. Analysis of the proteome revealed that protein expression patterns, in particular capsid and other structural proteins, closely follow the timing of the observed infection cycle. Together, these analyses provided the first detailed view of a viral infection in a highly lethal aquatic bacterium. The apparent temperate nature of this virus suggests that it can be a source of mortality to V. vulnificus, but has evolved to avoid total destruction of its host by complete lysis, a characteristic that helps ensure its replication in subsequent generations.

The genome and structural proteome of YuA, a new Pseudomonas aeruginosa phage resembling M6.

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Ceyssens, Pieter-Jan; Mesyanzhinov, Vadim; Sykilinda, Nina; Briers, Yves; Roucourt, Bart; Lavigne, Rob; Robben, Johan; Domashin, Artem; Miroshnikov, Konstantin; Volckaert, Guido; Hertveldt, Kirsten

2008-02-01

Pseudomonas aeruginosa phage YuA (Siphoviridae) was isolated from a pond near Moscow, Russia. It has an elongated head, encapsulating a circularly permuted genome of 58,663 bp, and a flexible, noncontractile tail, which is terminally and subterminally decorated with short fibers. The YuA genome is neither Mu- nor lambda-like and encodes 78 gene products that cluster in three major regions involved in (i) DNA metabolism and replication, (ii) host interaction, and (iii) phage particle formation and host lysis. At the protein level, YuA displays significant homology with phages M6, phiJL001, 73, B3, DMS3, and D3112. Eighteen YuA proteins were identified as part of the phage particle by mass spectrometry analysis. Five different bacterial promoters were experimentally identified using a promoter trap assay, three of which have a sigma54-specific binding site and regulate transcription in the genome region involved in phage particle formation and host lysis. The dependency of these promoters on the host sigma54 factor was confirmed by analysis of an rpoN mutant strain of P. aeruginosa PAO1. At the DNA level, YuA is 91% identical to the recently (July 2007) annotated phage M6 of the Lindberg typing set. Despite this level of DNA homology throughout the genome, both phages combined have 15 unique genes that do not occur in the other phage. The genome organization of both phages differs substantially from those of the other known Pseudomonas-infecting Siphoviridae, delineating them as a distinct genus within this family.

Control of Pierce's Disease by Phage.

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Mayukh Das

Full Text Available Pierce's Disease (PD of grapevines, caused by Xylella fastidiosa subsp. fastidiosa (Xf, is a limiting factor in the cultivation of grapevines in the US. There are presently no effective control methods to prevent or treat PD. The therapeutic and prophylactic efficacy of a phage cocktail composed of four virulent (lytic phages was evaluated for control of PD. Xf levels in grapevines were significantly reduced in therapeutically or prophylactically treated grapevines. PD symptoms ceased to progress one week post-therapeutic treatment and symptoms were not observed in prophylactically treated grapevines. Cocktail phage levels increased in grapevines in the presence of the host. No in planta phage-resistant Xf isolates were obtained. Moreover, Xf mutants selected for phage resistance in vitro did not cause PD symptoms. Our results indicate that phages have great potential for biocontrol of PD and other economically important diseases caused by Xylella.

Misperceptions about the risks of abortion in women presenting for abortion.

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Wiebe, Ellen R; Littman, Lisa; Kaczorowski, Janusz; Moshier, Erin L

2014-03-01

Misinformation about the risks and sequelae of abortion is widespread. The purpose of this study was to examine whether women having an abortion who believe that there should be restrictions to abortion (i.e., that some other women should not be allowed to have an abortion) also believe this misinformation about the health risks associated with abortion. We carried out a cross-sectional survey of women presenting consecutively for an abortion at an urban abortion clinic in Vancouver, British Columbia, between February and September 2012. Of 1008 women presenting for abortion, 978 completed questionnaires (97% response rate), and 333 of these (34%) favoured abortion restrictions. More women who favoured restrictions believed that the health risk of an abortion was the same as or greater than the health risk of childbirth (84.2% vs. 65.6%, P abortion caused mental health problems (39.1% vs. 28.3%, P abortion caused infertility (41.7% vs. 21.9%, P abortion should not be restricted was found to be a significantly correlated with correct answers about health risks, mental health problems, and infertility. Misinformed beliefs about the risks of abortion are common among women having an abortion. Women presenting for abortion who favoured restrictions to abortion have more misperceptions about abortion risks than women who favour no restrictions.

Reduced disease in black abalone following mass mortality: Phage therapy and natural selection

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VanBlaricom, Glenn R.

2014-01-01

Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS). Natural recovery on San Nicolas Island (SNI) of Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO) had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv) reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus) coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host–parasite relationships will better enable us to manage declining populations.

Reduced disease in black abalone following mass mortality: Phage therapy and natural selection

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Carolyn S Friedman

2014-03-01

Full Text Available Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS. Natural recovery on San Nicolas Island (SNI off Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point (CP in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host-parasite relationships will better enable us to manage declining populations.

Reduced disease in black abalone following mass mortality: phage therapy and natural selection.

Science.gov (United States)

Friedman, Carolyn S; Wight, Nathan; Crosson, Lisa M; Vanblaricom, Glenn R; Lafferty, Kevin D

2014-01-01

Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS). Natural recovery on San Nicolas Island (SNI) of Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO) had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv) reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus) coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host-parasite relationships will better enable us to manage declining populations.

Prevalence and epidemiological features of ovine enzootic abortion in Lithuania.

Science.gov (United States)

Bagdonas, J; Petkevicius, S; Russo, P; Pepin, M; Salomskas, A

2007-01-01

The aim of performed study was to determine the level of enzootic abortion (EA) in sheep breeding farms in different districts of Lithuania, to determine differences in clinical signs and infection frequency between various age groups, and to evaluate the sensitivity and specificity of complement fixation test for antibodies detection and indirect immunofluorescence for antigen detection in sheep chlamydiosis. The clinical, serological and immunological tests in sheep farms were performed in 2004 and 2005. Comparing different age groups of sheep revealed that the lowest number of infected sheep was registered in animals younger than 18 months (23.1%, antibodies titre 3.191 log2, Pabortus infection. The highest prevalence of chlamydia (66.7%) was registered in placentas of sheep which aborted.

Prevalence of Mycoplasma genitalium, Mycoplasma hominis and Chlamydia trachomatis among Danish patients requesting abortion

DEFF Research Database (Denmark)

Baczynska, Agata; Hvid, Malene; Lamy, P

2008-01-01

. There was no correlation between the presence of genital infection with C. trachomatis and genital mycoplasmas and no correlation between the presence of antibodies to these bacteria. In conclusion, in Danish patients it is not necessary to test for M. genitalium before abortion since less than 1% were found positive....... The prevalence of genital C. trachomatis infections was high among the abortion-seeking patients....

Differential infection properties of three inducible prophages from an epidemic strain of Pseudomonas aeruginosa

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James Chloe E

2012-09-01

Full Text Available Abstract Background Pseudomonas aeruginosa is the most common bacterial pathogen infecting the lungs of patients with cystic fibrosis (CF. The Liverpool Epidemic Strain (LES is transmissible, capable of superseding other P. aeruginosa populations and is associated with increased morbidity. Previously, multiple inducible prophages have been found to coexist in the LES chromosome and to constitute a major component of the accessory genome not found in other sequenced P. aerugionosa strains. LES phages confer a competitive advantage in a rat model of chronic lung infection and may, therefore underpin LES prevalence. Here the infective properties of three LES phages were characterised. Results This study focuses on three of the five active prophages (LESφ2, LESφ3 and LESφ4 that are members of the Siphoviridae. All were induced from LESB58 by norfloxacin. Lytic production of LESφ2 was considerably higher than that of LESφ3 and LESφ4. Each phage was capable of both lytic and lysogenic infection of the susceptible P. aeruginosa host, PAO1, producing phage-specific plaque morphologies. In the PAO1 host background, the LESφ2 prophage conferred immunity against LESφ3 infection and reduced susceptibility to LESφ4 infection. Each prophage was less stable in the PAO1 chromosome with substantially higher rates of spontaneous phage production than when residing in the native LESB58 host. We show that LES phages are capable of horizontal gene transfer by infecting P. aeruginosa strains from different sources and that type IV pili are required for infection by all three phages. Conclusions Multiple inducible prophages with diverse infection properties have been maintained in the LES genome. Our data suggest that LESφ2 is more sensitive to induction into the lytic cycle or has a more efficient replicative cycle than the other LES phages.

Phages of Lactobacillus casei/paracasei: response to environmental factors and interaction with collection and commercial strains.

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Capra, M L; Quiberoni, A; Reinheimer, J

2006-02-01

To investigate the influence of several environmental factors on the viability and cell-adsorption for two Lactobacillus casei/paracasei bacteriophages (PL-1 and J-1). Both phages showed a remarkably high specificity of species, sharing similar host spectra. Two phages and four sensitive strains were used to conform five phage/strain systems. Each showed a particular behaviour (burst size: ranging from 32 to 160 PFU/infective centre; burst time: 120-240 min and latent time: 5-90 min). For both phages, the viability was not significantly affected from pH 4 to 11 (room temperature) and from pH 5 to 10 (37 degrees C). Adsorption rates were not influenced by calcium ions, but decreased after the thermal inactivation of cells. Adsorption rates were high between 0 and 50 degrees C with maximum values at 30 degrees C and pH 6. System PL-1/Lact. paracasei A showed noticeable differences in comparison with the others, being times required to reach 90% of adsorption of 4 h and lower than 45 min, respectively. The data obtained in this work demonstrated that environmental parameters can influence the viability and cell adsorption rates of Lact. casei/paracasei phages. The extent of this influence was phage dependent. This work contributes to the enlargement of the currently scarce knowledge of phages of probiotic bacteria.

Access to abortion: what women want from abortion services.

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Wiebe, Ellen R; Sandhu, Supna

2008-04-01

Whether Canadian physicians can refuse to refer women for abortion and whether private clinics can charge for abortions are matters of controversy. We sought to identify barriers to access for women seeking therapeutic abortion and to have them identify what they considered to be most important about access to abortion services. Women presenting for abortion over a two-month period at two free-standing abortion clinics, one publicly funded and the other private, were invited to participate in the study. Phase I of the study involved administration of a questionnaire seeking information about demographics, perceived barriers to access to abortion, and what the women wanted from abortion services. Phase II involved semi-structured interviews of a convenience sample of women to record their responses to questions about access. Responses from Phase I questionnaires were compared between the two clinics, and qualitative analysis was performed on the interview responses. Of 423 eligible women, 402 completed questionnaires, and of 45 women approached, 39 completed interviews satisfactorily. Women received information about abortion services from their physicians (60.0%), the Internet (14.8%), a telephone directory (7.8%), friends or family (5.3%), or other sources (12.3%). Many had negative experiences in gaining access. The most important issue regarding access was the long wait time; the second most important issue was difficulty in making appointments. In the private clinic, 85% of the women said they were willing to pay for shorter wait times, compared with 43.5% in the public clinic. Physicians who failed to refer patients for abortion or provide information about obtaining an abortion caused distress and impeded access for a significant minority of women requesting an abortion. Management of abortion services should be prioritized to reflect what women want: particularly decreased wait times for abortion and greater ease and convenience in booking appointments

Incidence of Induced Abortion and Post-Abortion Care in Tanzania.

Science.gov (United States)

Keogh, Sarah C; Kimaro, Godfather; Muganyizi, Projestine; Philbin, Jesse; Kahwa, Amos; Ngadaya, Esther; Bankole, Akinrinola

2015-01-01

Tanzania has one of the highest maternal mortality ratios in the world, and unsafe abortion is one of its leading causes. Yet little is known about its incidence. To provide the first ever estimates of the incidence of unsafe abortion in Tanzania, at the national level and for each of the 8 geopolitical zones (7 in Mainland plus Zanzibar). A nationally representative survey of health facilities was conducted to determine the number of induced abortion complications treated in facilities. A survey of experts on abortion was conducted to estimate the likelihood of women experiencing complications and obtaining treatment. These surveys were complemented with population and fertility data to obtain abortion numbers, rates and ratios, using the Abortion Incidence Complications Methodology. In Tanzania, women obtained just over 405,000 induced abortions in 2013, for a national rate of 36 abortions per 1,000 women age 15-49 and a ratio of 21 abortions per 100 live births. For each woman treated in a facility for induced abortion complications, 6 times as many women had an abortion but did not receive care. Abortion rates vary widely by zone, from 10.7 in Zanzibar to 50.7 in the Lake zone. The abortion rate is similar to that of other countries in the region. Variations by zone are explained mainly by differences in fertility and contraceptive prevalence. Measures to reduce the incidence of unsafe abortion and associated maternal mortality include expanding access to post-abortion care and contraceptive services to prevent unintended pregnancies.

A study on relationship be tween genital chlamydia trachomatis and ureaplasma urealyticum infection and spontaneous abortion%生殖道沙眼衣原体和解脲支原体感染与自然流产的相关性研究

Institute of Scientific and Technical Information of China (English)

周萍

2015-01-01

目的：探讨生殖道沙眼衣原体和解脲支原体感染与自然流产的关系。方法选取我院自然流产患者（自然流产组）及人工流产患者（对照组），各60例。两组均采集宫颈分泌物及蜕膜组织进行沙眼衣原体和解脲支原体培养，分析结果。结果自然流产组宫颈分泌物及蜕膜组织中沙眼衣原体、解脲支原体、沙眼衣原体＋解脲支原体感染率均高于对照组（ P＜0．01）。结论生殖道沙眼衣原体和解脲支原体感染率与自然流产关系密切，可作为确定自然流产病因的指标。%Objective To explore the corelation of genital chlamydia trachomatis and ureaplasma urealyticum infection with spontaneous abortion,and provide clinical reference for the prevention and control of spontaneous abortion .Methods Patients with spontaneous abortion were selected as spontaneous abortion group ( n =60) and artificial abortion group ( n =60), and cervical se-cretions and decidual tissue of chlamydia trachomatis and ureaplasma urealyticum were cultured and the results were analyzed .Results Infection rate of chlamydia trachomatis in cervical secretion of the natural abortion group ,ureaplasma urealyticum,chlamydia trachom-atis infection +UU rates of the natural abortion group were higher than that of the control group ( P <0.01).Conclusion Infection rate of genital chlamydia trachomatis and ureaplasma urealyticum infection rate and spontaneous abortion have a close relationship , which may be one of the causes of spontaneous abortion .

Bacteriophages and their derivatives for the treatment and control of food-producing animal infections.

Science.gov (United States)

Carvalho, Carla; Costa, Ana Rita; Silva, Filipe; Oliveira, Ana

2017-09-01

Nowadays, the world is facing an increasing emergence of antibiotic resistant bacteria. Simultaneously, the banning of some existing antibiotics and the lack of development of new antimicrobials have created an urgent need to find new alternatives against animal infections. Bacteriophages (phages) are naturally occurring predators of bacteria, ubiquitous in the environment, with high host specificity and harmless to animals. For these reasons, phages and their derivatives are being considered valuable antimicrobial alternatives and an opportunity to reduce the current use of antibiotics in agri-food production, increasing animal productivity and providing environmental protection. Furthermore, the possibility of combining phage genetic material with foreign genes encoding peptides of interest has enabled their use as vaccine delivery tools. In this case, besides bacterial infections, they might be used to prevent viral infections. This review explores current data regarding advances on the use of phages and phage-encoded proteins, such as endolysins, exolysins and depolymerases, either for therapeutic or prophylactic applications, in animal husbandry. The use of recombinant phage-derived particles or genetically modified phages, including phage vaccines, will also be reviewed.

Phage or foe: an insight into the impact of viral predation on microbial communities.

Science.gov (United States)

Fernández, Lucía; Rodríguez, Ana; García, Pilar

2018-05-01

Since their discovery, bacteriophages have been traditionally regarded as the natural enemies of bacteria. However, recent advances in molecular biology techniques, especially data from "omics" analyses, have revealed that the interplay between bacterial viruses and their hosts is far more intricate than initially thought. On the one hand, we have become more aware of the impact of viral predation on the composition and genetic makeup of microbial communities thanks to genomic and metagenomic approaches. Moreover, data obtained from transcriptomic, proteomic, and metabolomic studies have shown that responses to phage predation are complex and diverse, varying greatly depending on the bacterial host, phage, and multiplicity of infection. Interestingly, phage exposure may alter different phenotypes, including virulence and biofilm formation. The complexity of the interactions between microbes and their viral predators is also evidenced by the link between quorum-sensing signaling pathways and bacteriophage resistance. Overall, new data increasingly suggests that both temperate and virulent phages have a positive effect on the evolution and adaptation of microbial populations. From this perspective, further research is still necessary to fully understand the interactions between phage and host under conditions that allow co-existence of both populations, reflecting more accurately the dynamics in natural microbial communities.

Large palindromes in the lambda phage genome are preserved in a rec/sup +/ host by inhibiting lambda DNA replication

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Shurvinton, C.E.; Stahl, M.M.; Stahl, F.W.

1987-03-01

A large palindrome carried by phage lambda has been shown to prevent growth of the phage on a rec/sup +/ strain of Escherichia coli. The phage do form plaques on recBC sbcB strains, but the palindrome is not stable - deletions that either destroy the palindrome or diminish its size overgrow the original engineered palindrome-containing phage. The authors have prepared stocks of lambda carrying a palindrome that is 2 x 4200 base pairs long. lambda phage were density labeled by UV induction of lysogens grown in minimal medium containing (/sup 13/C) glucose and /sup 15/NH/sub 4/Cl. These phage stocks are produced by induction of a lysogen in which the two halves of the palindrome are stored at opposite ends of the prophage and are of sufficient titer (10/sup 9/ phage per ml) to enable one-step growth experiments with replication-blocked phage. They find that the large palindrome as well as a lesser palindrome of 2 x 265 base pairs are recovered intact among particles carrying unreplicated chromosomes following such an infection of a rec/sup +/ host. they propose that DNA replication drives the extrusion of palindromic sequences in vivo, forming secondary structures that are substrates for the recBC and sbcB gene products.

Phages of life - the path to pharma.

Science.gov (United States)

Forde, Amanda; Hill, Colin

2018-02-01

Bacteriophage (phage) therapy has encountered both enthusiasm and scepticism in the past century. New antimicrobial strategies against lethal pathogens are now a top priority for the World Health Organization, and although compassionate use of phages recently met with significant success, regulated clinical interventions seem unlikely in the near future. The hundredth anniversary of their discovery seems an appropriate time for a revival of phage therapy, particularly as the dilemma of antibiotic resistance grows. Phages are ubiquitous in the environment, on our food and in and on our bodies. Their influence on human health is currently being evaluated, and in this mini-review, we examine data from recent metagenomic studies that propose a role for phages in the structure of the microbiome and in health and disease. We assess evidence for phages as vehicles for gene transfer in the context of antibiotic resistance and discuss challenges and opportunities along the critical path from phage discovery to a patient-focused pharmaceutical intervention. © 2017 The British Pharmacological Society.

TRANSDUCTION OF BACILLUS LICHENIFORMIS AND BACILLUS SUBTILIS BY EACH OF TWO PHAGES1

Science.gov (United States)

Taylor, Martha J.; Thorne, Curtis B.

1963-01-01

Taylor, Martha J. (U.S. Army Biological Laboratories, Fort Detrick, Frederick, Md.) and Curtis B. Thorne. Transduction of Bacillus licheniformis and Bacillus subtilis by each of two phages. J. Bacteriol. 86:452–461. 1963.—A second transducing bacteriophage, designated SP-15, was isolated from the same soil-sample culture filtrate that supplied the Bacillus subtilis transducing phage, SP-10, reported earlier from this laboratory. SP-10 and SP-15 differ serologically and in several other respects, but share the ability to propagate on B. subtilis W-23-Sr (streptomycin-resistant) and B. licheniformis ATCC 9945a, and to mediate general transduction in either species when propagated homologously. Attempts to transduce between the species have failed. SP-10 forms plaques readily on both W-23-Sr and 9945a; SP-15 forms minute plaques on W-23-Sr and has shown no evidence of any lytic activity on 9945a. Maximal recoveries of prototrophic colonies from mixtures of SP-10 with auxotrophs of either W-23-Sr or 9945a were obtained only when excess phage was neutralized by post-transduction treatment with specific phage antiserum. Such treatment was not necessary for maximal recovery of transductants effected by SP-15. Unlike SP-10, SP-15 propagated on W-23-Sr did not transduce B. subtilis 168 (indole−). SP-15 transduced B. licheniformis more efficiently than did SP-10. Neither phage was able to transduce B. licheniformis as efficiently as it transduced B. subtilis. The differing influences of multiplicity of infection were compared for the two phages in both species. PMID:14066421

The ltp gene of temperate Streptococcus thermophilus phage TP-J34 confers superinfection exclusion to Streptococcus thermophilus and Lactococcus lactis

International Nuclear Information System (INIS)

Sun Xingmin; Goehler, Andre; Heller, Knut J.; Neve, Horst

2006-01-01

The ltp gene, located within the lysogeny module of temperate Streptococcus thermophilus phage TP-J34, has been shown to be expressed in lysogenic strain S. thermophilus J34. It codes for a lipoprotein, as demonstrated by inhibition of cleavage of the signal sequence by globomycin. Exposure of Ltp on the surface of Lactococcus lactis protoplasts bearing a plasmid-encoded copy of ltp has been demonstrated by immunogold labeling and electron microscopy. Expression of ltp in prophage- and plasmid-cured S. thermophilus J34-6f interfered with TP-J34 infection. While plating efficiency was reduced by a factor of about 40 and lysis of strain J34-6f in liquid medium was delayed considerably, phage adsorption was not affected at all. Intracellular accumulation of phage DNA was shown to be inhibited by Ltp. This indicates interference of Ltp with infection at the stage of triggering DNA release and injection into the cell, indicating a role of Ltp in superinfection exclusion. Expression of ltp in L. lactis Bu2-60 showed that the same superinfection exclusion mechanism was strongly effective against phage P008, a member of the lactococcal 936 phage species: no plaque-formation was detectable with even 10 9 phage per ml applied, and lysis in liquid medium did not occur. In Lactococcus also, Ltp apparently inhibited phage DNA release and/or injection. Ltp appears to be a member of a family of small, secreted proteins with a 42 amino acids repeat structure encoded by genes of Gram-positive bacteria. Some of these homologous genes are part of the genomes of prophages

Pathogenic factors of Pseudomonas aeruginosa – the role of biofilm in pathogenicity and as a target for phage therapy

Directory of Open Access Journals (Sweden)

Fairoz Al-Wrafy

2017-02-01

Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen that can cause several acute and chronic infections in humans, and it has become an important cause of nosocomial infections and antibiotic resistance. Biofilm represents an important virulence factor for these bacteria, plays a role in P. aeruginosa infections and avoidance of immune defence mechanisms, and has the ability to protect the bacteria from antibiotics. Alginate, Psl and Pel, three exopolysaccharides, are the main components in biofilm matrix, with many biological functions attributed to them, especially with respect to the protection of the bacterial cell from antibiotics and the immune system. Pseudomonas infections, biofilm formation and development of resistance to antibiotics all require better understanding to achieve the best results using alternative treatment with phage therapy. This review describes the P. aeruginosa pathogenicity and virulence factors with a special focus on the biofilm and its role in infection and resistance to antibiotics and summarizes phage therapy as an alternative approach in treatment of P. aeruginosa infections.

Heat tolerance of dairy lactococcal c2 phages

DEFF Research Database (Denmark)

Nielsen, Cecilie Lykke Marvig; Basheer, Aideh; Neve, H.

2011-01-01

-order kinetics with correlation coefficients of 0.96–0.99. D70-values of 12 s and 16.6 min were calculated for the most sensitive and resistant phage, respectively. Release of phage DNA from capsids, and disintegration of phage heads and tails were among the first morphological changes observed for moderately...... thermal inactivated lysates (15% phage inactivation) of the heat tolerant phage P635....

Characterization of Bacillus phage-K2 isolated from chungkookjang, a fermented soybean foodstuff.

Science.gov (United States)

Kim, Eun Ju; Hong, Jeong Won; Yun, Na-Rae; Lee, Young Nam

2011-01-01

An investigation of a virulent Bacillus phage-K2 (named Bp-K2) isolated from chungkookjang (a fermented soybean foodstuff) was made. Bp-K2 differed in infectivity against a number of Bacillus subtilis strains including starter strains of chungkookjang and natto, being more infectious to Bacillus strains isolated from the chungkookjang, but much less active against a natto strain. Bp-K2 is a small DNA phage whose genome size is about 21 kb. Bp-K2 is a tailed bacteriophage with an isometric icosahedral head (50 nm long on the lateral side, 80 nm wide), a long contractile sheath (85-90 nm × 28 nm), a thin tail fiber (80-85 nm long, 10 nm wide), and a basal plate (29 nm long, 47 nm wide) with a number of spikes, but no collar. The details of the structures of Bp-K2 differ from natto phage ϕBN100 as well as other known Bacillus phages such as SPO1-like or ϕ 29-like viruses. These data suggest that Bp-K2 would be a new member of the Myoviridae family of Bacillus bacteriophages.

Thermal-Stability and Reconstitution Ability of Listeria Phages P100 and A511

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Hanie Ahmadi

2017-12-01

Full Text Available The study evaluated the thermal-stability of Listeria phages P100 and A511 at temperatures simulating the preparation of ready-to-eat meats. The phage infectivity after heating to 71°C and holding for a minimum of 30 s, before eventually cooling to 4°C were examined. Higher temperatures of 75, 80, and 85°C were also tested to evaluate their effect on phages thermal-stability. This study found that despite minor differences in the amino acid sequences of their structural proteins, the two phages responded differently to high temperatures. P100 activity declined at least 10 log (PFU mL-1 with exposure to 71°C (30 s and falling below the limit of detection (1 log PFU mL-1 while, A511 dropped from 108 to 105 PFU mL-1. Cooling resulted in partial reconstitution of P100 phage particles to 103 PFU mL-1. Exposure to 75°C (30 s abolished A511 activity (8 log PFU mL-1 and both phages showed reconstitution during cooling phase after exposure to 75°C. P100 exhibited reconstitution after treatment at 80°C (30 s, conversely A511 showed no reconstitution activity. Heating P100 to 85°C abolished the reconstitution potential. Substantial differences were found in thermal-stability and reconstitution of the examined phages showing A511 to be more thermo-stable than P100, while P100 exhibited reconstitution during cooling after treatment at 80°C which was absent in A511. The differences in predicted melting temperatures of structural proteins of P100 and A511 were consistent with the observed differences in thermal stability and morphological changes observed with transmission electron microscopy.

Recovery of the accumulation ability of thiomethyl-β-galactoside in Escherichia coli after bacteriophage T4 infection

International Nuclear Information System (INIS)

Saijo, N.; Okamoto, K.

1976-01-01

Effects of uv-irradiated and unirradiated T4 phage infection on the β-galactoside accumulation ability in Escherichia coli have been examined by the use of 14 C-labeled thiomethyl-β-galactoside (TMG). Under conditions where a synchronous adsorption of phage takes place, the cellular ability for TMG accumulation is found to be largely inhibited immediately after phage adsorption but it recovers with time to a new level, which is dependent on the multiplicity of infection. When cells are infected with uv-irradiated T4 at the same multiplicity as that of unirradiated phage, the cellular accumulation ability is more severely inhibited and there is no recovery from the inhibition. The recovery process in T4-infected cells is mostly sensitive to puromycin. These results suggest that the initial inhibition of the TMG accumulation ability is probably caused by the adsorption of phage coats, and the subsequent restoration occurs through the action of a phage-directed protein(s). In the recovery process, no new transport system appears to be involved. The restored ability of TMG accumulation is resistant to the action of superinfecting uv phage. However, different mechanisms appear to be operating in T4-infected cells for the establishment of resistance to ghosts and for the recovery from the phage coat-induced inhibition

The triviality of abortion in Greece.

Science.gov (United States)

Naziri, D

1991-09-01

In Greece modern contraceptive methods are used only in a very limited manner and abortion is the primary form of birth control. There are several social and psychological issues that are considered to be responsible. A 1985 study done for the Family Planning Center of Thessaloniki found that the ratio of live births is 1.3 and the ratio of abortion is 1.8/woman. 88% of women in the study had had an abortion while practicing coitus interruptus. 90% of the women never bought condoms. In a 1989 study only 6% of women had a positive attitude about condoms. Abortion is used as the primary method of birth control regardless of a woman's socioeconomic status. Further it was found that abortion did not correlate with other modern attitudes or the emancipation of women. The decision to abort was related to difficulties and constraints inherent in bring up a child. However positive attitudes toward contraception were related to educational and occupational levels. To complicate matters the information concerning contraceptives was problematic and related to the women's own lack of initiative to find out, and a lack of correct information offered from gynecologists. A 1990 study on knowledge, attitudes, beliefs and practices in relation to HIV infection indicated that the most favored method of contraception was condoms, but 60.8% of the men reported use versus 33.7% of the women. However these figures are not very representative because the survey was given in the context of HIV prevention and no attempt was made to distinguish between regular and irregular use patterns. Abortions is not a moral issue in Greece. It was legalized in 1986 only because it came to the attention of the government that the previous prohibition was being completely ignored. Abortion is strongly affected by social and psychological factors that are complex and result from cultural view points about fertility, maternal value, and life itself that are unique to the Greek culture.

Mental health consequences of abortion and refused abortion.

Science.gov (United States)

Watter, W W

1980-02-01

There is no scientific evidence to support the hypothesis put forth by Dr. Philip Ney in a recent article published in the Canadian Journal of Psychiatry that induced abortion is associated with an increase in child abuse. There are, however, numerous studies which support the contention that mandatory motherhood adversely affects the mental health of both the mother and the offspring. Studies conducted in Sweden, Scotland, and Czechoslovakia revealed that women who were refused abortions frequently experienced serious psychosocial difficulties for long periods of time following abortion refusal. Case controlled follow-up studies, conducted in Sweden and Czechoslovakia, of offspring born to women who were refused abortions demonstrated that a higher proportion of the unwanted children required psychiatric services, engaged in criminal behavior, and did less well in school than the controlled children. These studies have implications for the current Canadian law which permits a woman to obtain an abortion if pregnancy continuation will endanger her health. In view of the above statistical evidence, and the fact that mortality and morbidity are known to be lower for abortion than for childbirth, any person who denies a woman the right to have an abortion is increasing the risk that the health of the woman will be endangered. By law, therefore, all abortion requests should be honored.

Development of a phage typing system for Staphylococcus hyicus

DEFF Research Database (Denmark)

Wegener, Henrik Caspar

1993-01-01

Bacteriophages were released by 98% of 100 Staphylococcus hyicus strains studied after treatment with mitomycin C. Twenty-three phages with different lytic spectra were included in a phage typing system and used f or typing S. hyicus. On a test-set of 100 epidemiologically unrelated S. hyicus...... strains isolated from Danish pig herds, the phages were able to type 92% of the strains, producing 16 different phage types. Reproducibility of the phage typing system after subculture of the strains and using fresh phage stock was 96%. Typability ranged from 52 to 80% when typing porcine strains...... originating from other countries. Although phages were isolated from porcine skin strains exclusively, the system produced phage types in S. hyicus strains of bovine origin. Ten strains of S. aureus and S. chromogenes were not typable by these phages. Strains belonging to one phage type (A/B/C/W) were...

Blocking peptides against HBV: PreS1 protein selected from a phage display library

International Nuclear Information System (INIS)

Wang, Wei; Liu, Yang; Zu, Xiangyang; Jin, Rui; Xiao, Gengfu

2011-01-01

Highlights: → Successfully selected specific PreS1-interacting peptides by using phage displayed library. → Alignment of the positive phage clones revealed a consensus PreS1 binding motif. → A highly enriched peptide named P7 had a strong binding ability for PreS1. → P7 could block PreS1 attachment. -- Abstract: The PreS1 protein is present on the outermost part of the hepatitis B virus (HBV) surface and has been shown to have a pivotal function in viral infectivity and assembly. The development of reagents with high affinity and specificity for PreS1 is of great significance for early diagnosis and treatment of HBV infection. A phage display library of dodecapeptide was screened for interactions with purified PreS1 protein. Alignment of the positive phage clones revealed a putative consensus PreS1 binding motif of HX n HX m HP/R. Moreover, a peptide named P7 (KHMHWHPPALNT) was highly enriched and occurred with a surprisingly high frequency of 72%. A thermodynamic study revealed that P7 has a higher binding affinity to PreS1 than the other peptides. Furthermore, P7 was able to abrogate the binding of HBV virions to the PreS1 antibody, suggesting that P7 covers key functional sites on the native PreS1 protein. This newly isolated peptide may, therefore, be a new therapeutic candidate for the treatment of HBV. The consensus motif could be modified to deliver imaging, diagnostic, and therapeutic agents to tissues affected by HBV.

Blocking peptides against HBV: PreS1 protein selected from a phage display library

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Wang, Wei; Liu, Yang; Zu, Xiangyang; Jin, Rui [State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071 (China); Xiao, Gengfu, E-mail: xiaogf@wh.iov.cn [State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071 (China)

2011-09-09

Highlights: {yields} Successfully selected specific PreS1-interacting peptides by using phage displayed library. {yields} Alignment of the positive phage clones revealed a consensus PreS1 binding motif. {yields} A highly enriched peptide named P7 had a strong binding ability for PreS1. {yields} P7 could block PreS1 attachment. -- Abstract: The PreS1 protein is present on the outermost part of the hepatitis B virus (HBV) surface and has been shown to have a pivotal function in viral infectivity and assembly. The development of reagents with high affinity and specificity for PreS1 is of great significance for early diagnosis and treatment of HBV infection. A phage display library of dodecapeptide was screened for interactions with purified PreS1 protein. Alignment of the positive phage clones revealed a putative consensus PreS1 binding motif of HX{sub n}HX{sub m}HP/R. Moreover, a peptide named P7 (KHMHWHPPALNT) was highly enriched and occurred with a surprisingly high frequency of 72%. A thermodynamic study revealed that P7 has a higher binding affinity to PreS1 than the other peptides. Furthermore, P7 was able to abrogate the binding of HBV virions to the PreS1 antibody, suggesting that P7 covers key functional sites on the native PreS1 protein. This newly isolated peptide may, therefore, be a new therapeutic candidate for the treatment of HBV. The consensus motif could be modified to deliver imaging, diagnostic, and therapeutic agents to tissues affected by HBV.

[Screening serum response special antibodies of U251 cell line from surface display phage antibody library].

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Yu, Min; Tan, De-Yong; Qian, Wei; Lai, Jian-Hua; Sun, Gui-Lin

2004-05-01

U251 cell is a sensitive cell line to serum, which stops at G0 phase of cell cycle in no-serum medium, and recovers growth when the serum is added into no-serum medium. The cell can express corresponding proteins in different phase of cell cycle. Therefore it is very signification for the study of cell cycle regulation mechanism that explores these proteins. In this paper, the mouse antibody phage display library was added into the bottle in which the serum starvation U251 cells had been cultured, and the special antibody phages were absorbed. Then the absorbed antibody phages were amplified by adding E. coli TG1 and helper phage M13K07. Amplified antibody phages were added into bottle in which the serum cultured cell after serum starvation (follow named as serum recovered cells) were incubated, so that the cell absorbed the no-special antibody phages for the serum starvation cell and the special antibody phages were in supernatant. The remaining no-special antibody phages in the supernatant were discarded by repeating above program 3-4 times. The pure special antibody phages were gotten, and amplified by adding the host cell E. coli TG1 and helper phage M13K07. Then the host bacterium infected special antibody phage was spread on the plate medium with ampicillin, and the monoclonal antibody phages were gotten. Using same as above program, the monoclonal antibody phages absorbed specially for serum recovered U251 cells were obtained when the serum recovered cells instead of serum starvation cells and serum starvation cells instead of serum recovered cells. In this study, ninety-six positive monoclonal antibody phages that absorbed specially the serum starvation cells and eighty-two positive monoclonal antibody phages that absorbed specially the serum recovered cells were obtained. By using cell immunochemistry assay, two special signification antibodies were obtained. one (No.11) was the strong response in serum starvation cells, the other (No.2) was the strong

Outbreak of caprine abortion by Toxoplasma gondii in Midwest Brazil

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Flávio Henrique Bravim Caldeira

2011-11-01

Full Text Available An outbreak of abortion by Toxoplasma gondii in goats on a farm in the Brazilian Midwest is reported. Gross lesions were not observed in seven aborted fetuses submitted to the Veterinary Pathology Laboratory, Federal University of Mato Grosso, for necropsy investigation. The main histologic lesions were mononuclear cell pneumonia and necrotizing encephalitis in varying degrees of intensity. PCR for Brucella abortus and Neospora caninum and aerobic cultures were negative in all cases. Antibody titles against T. gondii varying from 1:1024 to 1:32.768 were detected in serum samples from four aborted goats. Nested-PCR assay for T. gondii were positive in brain samples of all cases submitted. These findings indicate that T. gondii infection should be considered in the diagnosis of abortion in goats in Midwest Brazil.

A novel Pseudomonas aeruginosa bacteriophage, Ab31, a chimera formed from temperate phage PAJU2 and P. putida lytic phage AF: characteristics and mechanism of bacterial resistance.

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Libera Latino

Full Text Available A novel temperate bacteriophage of Pseudomonas aeruginosa, phage vB_PaeP_Tr60_Ab31 (alias Ab31 is described. Its genome is composed of structural genes related to those of lytic P. putida phage AF, and regulatory genes similar to those of temperate phage PAJU2. The virion structure resembles that of phage AF and other lytic Podoviridae (S. enterica Epsilon 15 and E. coli phiv10 with similar tail spikes. Ab31 was able to infect P. aeruginosa strain PA14 and two genetically related strains called Tr60 and Tr162, out of 35 diverse strains from cystic fibrosis patients. Analysis of resistant host variants revealed different phenotypes, including induction of pigment and alginate overproduction. Whole genome sequencing of resistant variants highlighted the existence of a large deletion of 234 kbp in two strains, encompassing a cluster of genes required for the production of CupA fimbriae. Stable lysogens formed by Ab31 in strain Tr60, permitted the identification of the insertion site. During colonization of the lung in cystic fibrosis patients, P. aeruginosa adapts by modifying its genome. We suggest that bacteriophages such as Ab31 may play an important role in this adaptation by selecting for bacterial characteristics that favor persistence of bacteria in the lung.

Evaluating risk factors for endemic human Salmonella Enteritidis infections with different phage types in Ontario, Canada using multinomial logistic regression and a case-case study approach

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Varga Csaba

2012-10-01

Full Text Available Abstract Background Identifying risk factors for Salmonella Enteritidis (SE infections in Ontario will assist public health authorities to design effective control and prevention programs to reduce the burden of SE infections. Our research objective was to identify risk factors for acquiring SE infections with various phage types (PT in Ontario, Canada. We hypothesized that certain PTs (e.g., PT8 and PT13a have specific risk factors for infection. Methods Our study included endemic SE cases with various PTs whose isolates were submitted to the Public Health Laboratory-Toronto from January 20th to August 12th, 2011. Cases were interviewed using a standardized questionnaire that included questions pertaining to demographics, travel history, clinical symptoms, contact with animals, and food exposures. A multinomial logistic regression method using the Generalized Linear Latent and Mixed Model procedure and a case-case study design were used to identify risk factors for acquiring SE infections with various PTs in Ontario, Canada. In the multinomial logistic regression model, the outcome variable had three categories representing human infections caused by SE PT8, PT13a, and all other SE PTs (i.e., non-PT8/non-PT13a as a referent category to which the other two categories were compared. Results In the multivariable model, SE PT8 was positively associated with contact with dogs (OR=2.17, 95% CI 1.01-4.68 and negatively associated with pepper consumption (OR=0.35, 95% CI 0.13-0.94, after adjusting for age categories and gender, and using exposure periods and health regions as random effects to account for clustering. Conclusions Our study findings offer interesting hypotheses about the role of phage type-specific risk factors. Multinomial logistic regression analysis and the case-case study approach are novel methodologies to evaluate associations among SE infections with different PTs and various risk factors.

Isolation and characterization of φkm18p, a novel lytic phage with therapeutic potential against extensively drug resistant Acinetobacter baumannii.

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Gwan-Han Shen

Full Text Available AIMS: To isolate phages against extensively drug resistant Acinetobacter baumannii (XDRAB and characterize the highest lytic capability phage as a model to evaluate the potential on phage therapy. METHODS AND RESULTS: Eight phages were isolated from hospital sewage and showed narrow host spectrum. Phage φkm18p was able to effectively lyse the most XDRAB. It has a dsDNA genome of 45 kb in size and hexagonal head of about 59 nm in diameter and no tail. Bacterial population decreased quickly from 10(8 CFU ml(-1 to 10(3 CFU ml(-1 in 30 min by φkm18p. The 185 kDa lysis protein encoded by φkm18p genome was detected when the extracted protein did not boil before SDS-PAGE; it showed that the lysis protein is a complex rather than a monomer. Phage φkm18p improved human lung epithelial cells survival rates when they were incubated with A. baumannii. Combination of phages (φkm18p, φTZ1 and φ314 as a cocktail could lyse all genotype-varying XDRAB isolates. CONCLUSION: Infections with XDRAB are extremely difficult to treat and development of a phage cocktails therapy could be a therapeutic alternative in the future. Phage φkm18p is a good candidate for inclusion in phage cocktails.

Genome Sequences of Ilzat and Eleri, Two Phages Isolated Using Microbacterium foliorum NRRL B-24224

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Ali, Ilzat; Jones, Acacia Eleri; Mohamed, Aleem

2018-01-01

ABSTRACT Bacteriophages Ilzat and Eleri are newly isolated Siphoviridae infecting Microbacterium foliorum NRRL B-24224. The phage genomes are similar in length, G+C content, and architecture and share 62.9% nucleotide sequence identity. PMID:29650566

Identification of tumor associated single-chain Fv by panning and screening antibody phage library using tumor cells

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Nie, Yong-Zhan; He, Feng-Tian; Li, Zhi-Kui; Wu, Kai-Chun; Cao, Yun-Xin; Chen, Bao-Jun; Fan, Dai-Ming

2002-01-01

AIM: To study the feasibility of panning and screening phage-displaying recombinant single-chain variable fragment (ScFv) of anti-tumor monoclonal antibodies for fixed whole cells as the carriers of mAb-binding antigens. METHODS: The recombinant phage displaying libraries for anti-colorectal tumor mAb MC3Ab, MC5Ab and anti-gastric tumor mAb MGD1 was constructed. Panning and screening were carried out by means of modified fixation of colorectal and gastric tumor cells expressed the mAb-binding antigens. Concordance of binding specificity to tumor cells between phage clones and parent antibodies was analyzed. The phage of positive clones was identified with competitive ELISA, and infected by E. coli HB2151 to express soluble ScFv. RESULTS: The ratio of positive clones to MC3-ScF-MC5-ScFv and MGD1-ScFv were 60%, 24% and 30%. MC3-ScFv had Mr 32000 confirmed by Western blot. The specificity to antigen had no difference between 4 positive recombinant phage antibodies and MC3Ab. CONCLUSION: The modified process of fixing whole tumor cells is efficient, convenient and feasible to pan and screen the phage-displaying ScFv of anti-tumor monoclonal antibodies. PMID:12174367

Gene Expression Patterns during Light and Dark Infection of Prochlorococcus by Cyanophage.

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Luke R Thompson

Full Text Available Cyanophage infecting the marine cyanobacteria Prochlorococcus and Synechococcus require light and host photosystem activity for optimal reproduction. Many cyanophages encode multiple photosynthetic electron transport (PET proteins, which are presumed to maintain electron flow and produce ATP and NADPH for nucleotide biosynthesis and phage genome replication. However, evidence suggests phage augment NADPH production via the pentose phosphate pathway (PPP, thus calling into question the need for NADPH production by PET. Genes implicated in cyclic PET have since been identified in cyanophage genomes. It remains an open question which mode of PET, cyclic or linear, predominates in infected cyanobacteria, and thus whether the balance is towards producing ATP or NADPH. We sequenced transcriptomes of a cyanophage (P-HM2 and its host (Prochlorococcus MED4 throughout infection in the light or in the dark, and analyzed these data in the context of phage replication and metabolite measurements. Infection was robust in the light, but phage were not produced in the dark. Host gene transcripts encoding high-light inducible proteins and two terminal oxidases (plastoquinol terminal oxidase and cytochrome c oxidase-implicated in protecting the photosynthetic membrane from light stress-were the most enriched in light but not dark infection. Among the most diminished transcripts in both light and dark infection was ferredoxin-NADP+ reductase (FNR, which uses the electron acceptor NADP+ to generate NADPH in linear photosynthesis. The phage gene for CP12, which putatively inhibits the Calvin cycle enzyme that receives NADPH from FNR, was highly expressed in light infection. Therefore, both PET production of NADPH and its consumption by carbon fixation are putatively repressed during phage infection in light. Transcriptomic evidence is thus consistent with cyclic photophosphorylation using oxygen as the terminal electron acceptor as the dominant mode of PET under

Phage-Bacterial Dynamics with Spatial Structure: Self Organization around Phage Sinks Can Promote Increased Cell Densities.

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Bull, James J; Christensen, Kelly A; Scott, Carly; Jack, Benjamin R; Crandall, Cameron J; Krone, Stephen M

2018-01-29

Bacteria growing on surfaces appear to be profoundly more resistant to control by lytic bacteriophages than do the same cells grown in liquid. Here, we use simulation models to investigate whether spatial structure per se can account for this increased cell density in the presence of phages. A measure is derived for comparing cell densities between growth in spatially structured environments versus well mixed environments (known as mass action). Maintenance of sensitive cells requires some form of phage death; we invoke death mechanisms that are spatially fixed, as if produced by cells. Spatially structured phage death provides cells with a means of protection that can boost cell densities an order of magnitude above that attained under mass action, although the effect is sometimes in the opposite direction. Phage and bacteria self organize into separate refuges, and spatial structure operates so that the phage progeny from a single burst do not have independent fates (as they do with mass action). Phage incur a high loss when invading protected areas that have high cell densities, resulting in greater protection for the cells. By the same metric, mass action dynamics either show no sustained bacterial elevation or oscillate between states of low and high cell densities and an elevated average. The elevated cell densities observed in models with spatial structure do not approach the empirically observed increased density of cells in structured environments with phages (which can be many orders of magnitude), so the empirical phenomenon likely requires additional mechanisms than those analyzed here.

Isolation and characterization of polyvalent bacteriophages infecting multi drug resistant Salmonella serovars isolated from broilers in Egypt.

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Mahmoud, Mayada; Askora, Ahmed; Barakat, Ahmed Barakat; Rabie, Omar El-Farouk; Hassan, Sayed Emam

2018-02-02

In this study, we isolated and characterized three phages named as Salmacey1, Salmacey2 and Salmacey3, infecting multi drug resistant Salmonella serovars isolated from broilers in Egypt. The most prevalent Salmonella serovars were S. typhimurium, S. enteritidis, and S. kentucky. All these Salmonella serovars were found to be resistant to more than two of the ten antimicrobial agents tested. Only S. kentucky was found to be resistant to seven antimicrobial agents. Examination of these phage particles by transmission electron microscopy (TEM), demonstrated that two phages (Salmacey1, Salmacey2) were found to belong to family Siphoviridae, and Salmacey3 was assigned to the family Myoviridae. The results of host range assay revealed that these bacteriophages were polyvalent and thus capable of infecting four strains of Salmonella serovars and Citrobacter freundii. Moreover, the two phages (Salmacey1, Salmacey2) had a lytic effect on Enterobacter cloacae and Salmacey3 was able to infect E. coli. All phages could not infect S. para Typhi, Staphylococus aureus and Bacillus cereus. One-step growth curves of bacteriophages revealed that siphovirus phages (Salmacey1, Salmacey2) have burst size (80 and 90pfu per infected cell with latent period 35min and 40min respectively), and for the myovirus Salmacey3 had a burst size 110pfu per infected cell with latent period 60min. Molecular analyses indicated that these phages contained double-stranded DNA genomes. The lytic activity of the phages against the most multidrug resistant serovars S. kentucky as host strain was evaluated. The result showed that these bacteriophages were able to completely stop the growth of S. kentucky in vitro. These results suggest that phages have a high potential for phage application to control Salmonella serovars isolated from broilers in Egypt. Copyright © 2017. Published by Elsevier B.V.

Abortive Intestinal Infection With an Escherichia coli-Shigella flexneri Hybrid Strain

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Formal, Samuel B.; LaBrec, E. H.; Kent, T. H.; Falkow, S.

1965-01-01

Formal, Samuel B., (Walter Reed Army Institute of Research, Washington, D.C.), E. H. LaBrec, T. H. Kent, and S. Falkow. Abortive intestinal infection with an Escherichia coli-Shigella flexneri hybrid strain. J. Bacteriol. 89:1374–1382. 1965.—The mechanism of the apparent loss of virulence of an Escherichia coli-Shigella flexneri hybrid strain was studied. The parent Shigella strain caused a fatal enteric infection when fed to starved guinea pigs, and signs of dysentery followed its oral administration to monkeys. The hybrid strain failed to produce any apparent symptoms when fed to either of these species. The parent strain was shown to invade the intestinal mucosa of starved guinea pigs. This caused a severe inflammatory reaction in the lamina propria, which progressed to ulceration of the intestinal epithelium and resulted in death of the animal. The hybrid strain also invaded the intestinal mucosa and produced an inflammatory reaction. In this case, the inflammatory reaction subsided, the intestine returned to normal within 4 days after challenge, and the animal survived. Both fluorescent-antibody techniques and in vivo growth studies have shown that the hybrid strain can not maintain itself in the intestinal mucosa. Preliminary studies have indicated that a similar situation also exists in the monkey. It is concluded that the virulence of dysentery bacilli rests not only in the capacity to reach the lamina propria, but also in the ability to multiply in this region. Images PMID:14293011

Oral Phage Therapy of Acute Bacterial Diarrhea With Two Coliphage Preparations: A Randomized Trial in Children From Bangladesh

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Sarker, Shafiqul Alam; Sultana, Shamima; Reuteler, Gloria; Moine, Deborah; Descombes, Patrick; Charton, Florence; Bourdin, Gilles; McCallin, Shawna; Ngom-Bru, Catherine; Neville, Tara; Akter, Mahmuda; Huq, Sayeeda; Qadri, Firdausi; Talukdar, Kaisar; Kassam, Mohamed; Delley, Michèle; Loiseau, Chloe; Deng, Ying; El Aidy, Sahar; Berger, Bernard; Brüssow, Harald

2016-01-01

Background Antibiotic resistance is rising in important bacterial pathogens. Phage therapy (PT), the use of bacterial viruses infecting the pathogen in a species-specific way, is a potential alternative. Method T4-like coliphages or a commercial Russian coliphage product or placebo was orally given over 4 days to Bangladeshi children hospitalized with acute bacterial diarrhea. Safety of oral phage was assessed clinically and by functional tests; coliphage and Escherichia coli titers and enteropathogens were determined in stool and quantitative diarrhea parameters (stool output, stool frequency) were measured. Stool microbiota was studied by 16S rRNA gene sequencing; the genomes of four fecal Streptococcus isolates were sequenced. Findings No adverse events attributable to oral phage application were observed (primary safety outcome). Fecal coliphage was increased in treated over control children, but the titers did not show substantial intestinal phage replication (secondary microbiology outcome). 60% of the children suffered from a microbiologically proven E. coli diarrhea; the most frequent diagnosis was ETEC infections. Bacterial co-pathogens were also detected. Half of the patients contained phage-susceptible E. coli colonies in the stool. E. coli represented less than 5% of fecal bacteria. Stool ETEC titers showed only a short-lived peak and were otherwise close to the replication threshold determined for T4 phage in vitro. An interim analysis after the enrollment of 120 patients showed no amelioration in quantitative diarrhea parameter by PT over standard care (tertiary clinical outcome). Stool microbiota was characterized by an overgrowth with Streptococcus belonging to the Streptococcus gallolyticus and Streptococcus salivarius species groups, their abundance correlated with quantitative diarrhea outcome, but genome sequencing did not identify virulence genes. Interpretation Oral coliphages showed a safe gut transit in children, but failed to achieve

A Taxonomic Review of Clostridium difficile Phages and Proposal of a Novel Genus, “Phimmp04likevirus”

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Katherine R. Hargreaves

2015-05-01

Full Text Available Currently, only three phages that infect the medically important bacterium Clostridium difficile have been discussed by the International Committee of Viral Taxonomy (ICTV. They are all myoviruses, and have been assigned to the genus “phicd119likevirus”. An additional nine phages have since been described in the literature with their genome data available. The Phicd119likevirus is named after the type species: the myovirus ΦCD119 which was the first C. difficile phage to be sequenced. The two additional myoviruses, ϕCD27 and φC2, also fall into this genus based on the similarity of their genome and morphological characteristics. The other nine phages have not been assigned to this genus, and four of them do not fit the criteria for the current taxonomic grouping. We have applied protein clustering analysis to determine their phylogenetic relationships. From these results we propose an additional myoviridae genus, that we term “phiMMP04likevirus”.

Interaction between the genomes of Lactococcus lactis and phages of the P335 species

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Kelly, William J.; Altermann, Eric; Lambie, Suzanne C.; Leahy, Sinead C.

2013-01-01

Phages of the P335 species infect Lactococcus lactis and have been particularly studied because of their association with strains of L. lactis subsp. cremoris used as dairy starter cultures. Unlike other lactococcal phages, those of the P335 species may have a temperate or lytic lifestyle, and are believed to originate from the starter cultures themselves. We have sequenced the genome of L. lactis subsp. cremoris KW2 isolated from fermented corn and found that it contains an integrated P335 species prophage. This 41 kb prophage (Φ KW2) has a mosaic structure with functional modules that are highly similar to several other phages of the P335 species associated with dairy starter cultures. Comparison of the genomes of 26 phages of the P335 species, with either a lytic or temperate lifestyle, shows that they can be divided into three groups and that the morphogenesis gene region is the most conserved. Analysis of these phage genomes in conjunction with the genomes of several L. lactis strains shows that prophage insertion is site specific and occurs at seven different chromosomal locations. Exactly how induced or lytic phages of the P335 species interact with carbohydrate cell surface receptors in the host cell envelope remains to be determined. Genes for the biosynthesis of a variable cell surface polysaccharide and for lipoteichoic acids (LTAs) are found in L. lactis and are the main candidates for phage receptors, as the genes for other cell surface carbohydrates have been lost from dairy starter strains. Overall, phages of the P335 species appear to have had only a minor role in the adaptation of L. lactis subsp. cremoris strains to the dairy environment, and instead they appear to be an integral part of the L. lactis chromosome. There remains a great deal to be discovered about their role, and their contribution to the evolution of the bacterial genome. PMID:24009606

Provision of intrauterine contraception in association with first trimester induced abortion reduces the need of repeat abortion: first-year results of a randomized controlled trial.

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Pohjoranta, Elina; Mentula, Maarit; Gissler, Mika; Suhonen, Satu; Heikinheimo, Oskari

2015-11-01

Can the need of subsequent abortion be reduced by providing intrauterine contraception as a part of the abortion service? Provision of intrauterine devices (IUDs) in association with first trimester abortion more than halved the incidence of repeat abortion during the first year of follow-up. Following abortion, the incidence of subsequent abortion is high, up to 30-40%. In cohort studies, intrauterine contraception has reduced the need of repeat abortion by 60-70%. A randomized controlled trial. The main outcome measure was the incidence of subsequent induced abortions during the follow-up. Altogether 751 women seeking first trimester induced abortion were recruited and randomized into two groups. Randomization was accomplished by computer-assisted permuted-block randomization with random block sizes of four to six. The investigators did not participate in randomization, which was done before commencing the study. The participants were recruited between 18 October 2010 and 21 January 2013. The inclusion criteria were age ≥18 years, duration of pregnancy ≤12 weeks, accepting intrauterine contraception, residence in Helsinki and signing the informed consent form. Women with contraindications to intrauterine contraception, such as uterine anomaly, acute genital infection or pap-smear change requiring surgical treatment were ineligible to participate.This study was conducted in collaboration between the Department of Obstetrics and Gynaecology, University of Helsinki and Helsinki University Hospital, and Centralized family planning of the City of Helsinki.The intervention group (n = 375) was provided with intrauterine contraception (either the levonorgestrel-releasing intrauterine system or copper-releasing intrauterine device) immediately following surgical abortion (18.1%) or at a follow-up 2-4 weeks after medical abortion (81.9%). Women in the control group were prescribed oral contraceptives and advised to contact their primary healthcare unit for a follow

Provokeret abort

DEFF Research Database (Denmark)

Christiansen, Connie; Schmidt, Garbi; Christoffersen, Mogens

Gennem en række interview om kvinders oplevelse og erfaringer med provokert abort, samt ved at bruge data fra en stor forløbsundersøgelse af kvinder født i 1966, giver forfatterne bag denne rapport et præcist signalement af de kvinder, der vælger at få foretaget en provokeret abort og de eventuelle...... for sundhedspersonale og andre socialarbejdere. Den statistiske undersøgelse viser, at hver fjerde danske kvinde vil komme i den situation at skulle have en abort. Især kvinder med vanskelige opvækstvilkår er i risikogruppen. Tilgengæld er der næsten ingen langvarige fysiske og psykiske virkninger abort af abort, med...

Abortion legalized: challenges ahead.

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Singh, M; Jha, R

2007-01-01

To see whether advocacy for abortion law and comprehensive abortion care (CAC) sites after legalization of abortion in Nepal is adequate among educated people (above school leaving certificate). 150 participants were assigned randomly who agreed to be in the survey and were given structured questionnaires to find out their perception of abortion and CAC sites. Majority know abortion is legalized and majority have positive attitude about legalization of abortion, however majority are not aware of abortion service in CAC sites and none knew the cost of abortion service. Proper and adequate advocacy of the new abortion law and CAC service is essential.

The politicization of abortion and the evolution of abortion counseling.

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Joffe, Carole

2013-01-01

The field of abortion counseling originated in the abortion rights movement of the 1970s. During its evolution to the present day, it has faced significant challenges, primarily arising from the increasing politicization and stigmatization of abortion since legalization. Abortion counseling has been affected not only by the imposition of antiabortion statutes, but also by the changing needs of patients who have come of age in a very different era than when this occupation was first developed. One major innovation--head and heart counseling--departs in significant ways from previous conventions of the field and illustrates the complex and changing political meanings of abortion and therefore the challenges to abortion providers in the years following Roe v Wade.

Phage typing of Staphylococcus saprophyticus.

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Torres Pereira, A.; Melo Cristino, J. A.

1991-01-01

This study included 502 staphylococcus strains; Staphylococcus saprophyticus (297 strains) S. cohnii (47), S. xylosus (10), S. epidermidis (67) and S. aureus (81). Mitomycin C induction was performed on 100 isolates of S. saprophyticus and all induced strains were reacted with each other. Twenty-six strains proved to be lysogenic. Phages were propagated and titrated. With 12 of the phages there were three frequent associations, named lytic groups A, B and C, which included 75% of all typable strains. Typability of the system was 45% and reproducibility was between 94.2% and 100%. Phages did not lyse S. aureus and S. epidermidis strains, but they lysed S. saprophyticus and only rare strains of other novobiocin resistant species. Effective S. saprophyticus typing serves ecological purposes and tracing the origin of urinary strains from the skin or mucous membranes. Phage typing in association with plasmid profiling previously described, are anticipated as complementary methods with strong discriminatory power for differentiating among S. saprophyticus strains. PMID:1752305

Conceptualising abortion stigma

NARCIS (Netherlands)

Kumar, Anuradha; Hessini, Leila; Mitchell, Ellen M. H.

2009-01-01

Abortion stigma is widely acknowledged in many countries, but poorly theorised. Although media accounts often evoke abortion stigma as a universal social fact, we suggest that the social production of abortion stigma is profoundly local. Abortion stigma is neither natural nor 'essential' and relies

Abortion

Science.gov (United States)

An abortion is a procedure to end a pregnancy. It uses medicine or surgery to remove the embryo or ... personal. If you are thinking of having an abortion, most health care providers advise counseling.

Abortion denied--outcome of mothers and babies.

Science.gov (United States)

Del Campo, C

1984-02-15

A consistent argument favoring therapeutic abortions has been that mothers who are denied abortions will seek "illegal" help elsewhere, often in less than optimal conditions. Yet, a review of published reports on women who had been denied abortion and were followed up shows that 70.67% of the 6298 women completed their pregnancies and only 13.2% had an abortion elsewhere. Several studies have shown that the incidence of Complications of pregnancy is no greater in mothers denied abortion than in paired controls. The results of a prospective study by Laukaran and Van Den Berg showed a higher incidence of maternal accidental injury, a borderline increase of maternal accidental injury, a borderline increase in the prevalence of congenital anomalies, and a higher incidence of infection and hemorrhage during the puerperium in women who had been denied abortion. They concluded that maternal attitude and psychosocial stress had little effect on the progress of the pregnancy and labor. Published reports on the psychological effects on the children of women who had been denied abortion are few, mainly because longterm follow-up is required. In 1966 Forssman and Thuwe described the results of their study of 120 children whose mothers had been denied abortion. The children had been followed up until their 21st birthdays. The controls had been carefully paired. The proportion of children who had been placed in foster and children's homes was significantly higher among the "unwanted" children than among the controls (50% versus 18%). There was no statistically significant difference in the rates of drunken misconduct, crime, or "educational mental subnormality" between the 2 groups, but the incidence rates of delinquency and psychiatric consultation were 10% and 13% higher respectively among the unwanted children than among the controls. There have been virtually no objective studies on the psychologic and social well-being of women who have been denied abortion. The literature

Abortion: a history.

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Hovey, G

1985-01-01

This review of abortion history considers sacred and secular practice and traces abortion in the US, the legacy of the 19th century, and the change that occurred in the 20th century. Abortion has been practiced since ancient times, but its legality and availability have been threatened continuously by forces that would denigrate women's fundamental rights. Currently, while efforts to decrease the need for abortion through contraception and education continue, access to abortion remains crucial for the well-being of millions of women. That access will never be secure until profound changes occur in the whole society. Laws that prohibit absolutely the practice of abortion are a relatively recent development. In the early Roman Catholic church, abortion was permitted for male fetuses in the first 40 days of pregnancy and for female fetuses in the first 80-90 days. Not until 1588 did Pope Sixtus V declare all abortion murder, with excommunication as the punishment. Only 3 years later a new pope found the absolute sanction unworkable and again allowed early abortions. 300 years would pass before the Catholic church under Pius IX again declared all abortion murder. This standard, declared in 1869, remains the official position of the church, reaffirmed by the current pope. In 1920 the Soviet Union became the 1st modern state formally to legalize abortion. In the early period after the 1917 revolution, abortion was readily available in state operated facilities. These facilities were closed and abortion made illegal when it became clear that the Soviet Union would have to defend itself against Nazi Germany. After World War II women were encouraged to enter the labor force, and abortion once again became legal. The cases of the Catholic church and the Soviet Union illustrate the same point. Abortion legislation has never been in the hands of women. In the 20th century, state policy has been determined by the rhythms of economic and military expansion, the desire for cheap

Religion and attitudes toward abortion and abortion policy in Brazil.

Science.gov (United States)

Ogland, Curtis P; Verona, Ana Paula

2011-01-01

This study examines the association between religion and attitudes toward the practice of abortion and abortion policy in Brazil. Drawing upon data from the 2002 Brazilian Social Research Survey (BSRS), we test a number of hypotheses with regard to the role of religion on opposition to the practice of abortion and its legalization. Findings indicate that frequently attending Pentecostals demonstrate the strongest opposition to the practice of abortion and both frequently attending Pentecostals and Catholics demonstrate the strongest opposition to its legalization. Additional religious factors, such as a commitment to biblical literalism, were also found to be significantly associated with opposition to both abortion issues. Ultimately, the findings have implications for the future of public policy on abortion and other contentious social issues in Brazil.

Use of phages against antibiotic-resistant Staphylococcus aureus isolated from bovine mastitis.

Science.gov (United States)

Dias, R S; Eller, M R; Duarte, V S; Pereira, Â L; Silva, C C; Mantovani, H C; Oliveira, L L; Silva, E de A M; De Paula, S O

2013-08-01

Bovine mastitis is the primary disease of dairy cattle worldwide and it causes large economic losses. Among several microorganisms that are the causative agents of this disease, Staphylococcus aureus is the most prevalent. Although antibiotic therapy is still the most widely used procedure for the treatment of bovine mastitis, alternative means of treatment are necessary due to the presence of antibiotic residues in milk, which is a growing concern because of its interference with the production of milk derivatives and the selection of resistant bacterial strains. The use of bacteriophages as a tool for the control of pathogens is an alternative treatment to antibiotic therapy. In this work, to obtain phages with the potential for use in phage therapy as a treatment for mastitis, we isolated and identified the bacteria from the milk of mastitis-positive cows. A total of 19% of the animals from small and medium farms of the Zona da Mata Mineira, Brazil, was positive for bovine mastitis, and bacteria of the genus Staphylococcus were the most prevalent pathogens. The majority of the S. aureus isolates tested was resistant to penicillin and ampicillin. In parallel, we isolated 10 bacteriophages able to infect some of these S. aureus isolates. We determined that these phages contained DNA genomes of approximately 175 kb in length, and the protein profiles indicated the presence of 4 major proteins. Electron microscopy revealed that the phages are caudate and belong to the Myoviridae family. The isolates exhibited interesting features for their use in phage therapy such as a high lytic potential, a wide range of hosts, and thermostability, all of which favor their use in the field.

Characterization of bacteriophages infecting clinical isolates of Pseudomonas aeruginosa stored in a culture collection

Directory of Open Access Journals (Sweden)

C.C.S. Zanetti

2013-08-01

Full Text Available Some clinical isolates of Pseudomonas aeruginosa stored in our culture collection did not grow or grew poorly and showed lysis on the culture plates when removed from the collection and inoculated on MacConkey agar. One hypothesis was that bacteriophages had infected and killed those clinical isolates. To check the best storage conditions to maintain viable P. aeruginosa for a longer time, clinical isolates were stored at various temperatures and were grown monthly. We investigated the presence of phage in 10 clinical isolates of P. aeruginosa stored in our culture collection. Four strains of P. aeruginosa were infected by phages that were characterized by electron microscopy and isolated to assess their ability to infect. The best condition to maintain the viability of the strains during storage was in water at room temperature. Three Siphoviridae and two Myoviridae phages were visualized and characterized by morphology. We confirmed the presence of bacteriophages infecting clinical isolates, and their ability to infect and lyse alternative hosts. Strain PAO1, however, did not show lysis to any phage. Mucoid and multidrug resistant strains of P. aeruginosa showed lysis to 50% of the phages tested.

Abortion trends from 1996 to 2011 in Estonia: special emphasis on repeat abortion

Science.gov (United States)

2014-01-01

Background The study aimed to describe the overall and age-specific trends of induced abortions from 1996 to 2011 with an emphasis on socio-demographic characteristics and contraceptive use of women having had repeat abortions in Estonia. Methods Data were retrieved from the Estonian Medical Birth and Abortion Registry and Statistics Estonia. Total induced abortion numbers, rates, ratios and age-specific rates are presented for 1996–2011. The percentage change in the number of repeat abortions within selected socio-demographic subgroups, contraception use and distribution of induced abortions among Estonians and non-Estonians for the first, second, third, fourth and subsequent abortions were calculated for the periods 1996–2003 and 2004–2011. Results Observed trends over the 16-year study period indicated a considerable decline in induced abortions with a reduction in abortion rate of 57.1%, which was mainly attributed to younger cohorts. The percentage of women undergoing repeat abortions fell steadily from 63.8% during 1996–2003 to 58.0% during 2004–2011. The percentage of women undergoing repeat abortions significantly decreased over the 16 years within all selected socio-demographic subgroups except among women with low educational attainment and students. Within each time period, a greater percentage of non-Estonians than Estonians underwent repeat abortions and obtained third and subsequent abortions. Most women did not use any contraceptive method prior to their first or subsequent abortion. Conclusion A high percentage of women obtaining repeat abortions reflects a high historical abortion rate. If current trends continue, a rapid decline in repeat abortions may be predicted. To decrease the burden of sexual ill health, routine contraceptive counselling, as standard care in the abortion process, should be seriously addressed with an emphasis on those groups - non-Estonians, women with lower educational attainment, students and women with children

The tripartite capsid gene of Salmonella phage Gifsy-2 yields a capsid assembly pathway engaging features from HK97 and λ

International Nuclear Information System (INIS)

Effantin, Gregory; Figueroa-Bossi, Nara; Schoehn, Guy; Bossi, Lionello; Conway, James F.

2010-01-01

Phage Gifsy-2, a lambdoid phage infecting Salmonella, has an unusually large composite gene coding for its major capsid protein (mcp) at the C-terminal end, a ClpP-like protease at the N-terminus, and a ∼ 200 residue central domain of unknown function but which may have a scaffolding role. This combination of functions on a single coding region is more extensive than those observed in other phages such as HK97 (scaffold-capsid fusion) and λ (protease-scaffold fusion). To study the structural phenotype of the unique Gifsy-2 capsid gene, we have purified Gifsy-2 particles and visualized capsids and procapsids by cryoelectron microscopy, determining structures to resolutions up to 12 A. The capsids have lambdoid T = 7 geometry and are well modeled with the atomic structures of HK97 mcp and phage λ gpD decoration protein. Thus, the unique Gifsy-2 capsid protein gene yields a capsid maturation pathway engaging features from both phages HK97 and λ.

Misinformation on abortion.

Science.gov (United States)

Rowlands, Sam

2011-08-01

To find the latest and most accurate information on aspects of induced abortion. A literature survey was carried out in which five aspects of abortion were scrutinised: risk to life, risk of breast cancer, risk to mental health, risk to future fertility, and fetal pain. Abortion is clearly safer than childbirth. There is no evidence of an association between abortion and breast cancer. Women who have abortions are not at increased risk of mental health problems over and above women who deliver an unwanted pregnancy. There is no negative effect of abortion on a woman's subsequent fertility. It is not possible for a fetus to perceive pain before 24 weeks' gestation. Misinformation on abortion is widespread. Literature and websites are cited to demonstrate how data have been manipulated and misquoted or just ignored. Citation of non-peer reviewed articles is also common. Mandates insisting on provision of inaccurate information in some US State laws are presented. Attention is drawn to how women can be misled by Crisis Pregnancy Centres. There is extensive promulgation of misinformation on abortion by those who oppose abortion. Much of this misinformation is based on distorted interpretation of the scientific literature.

Morbidity and mortality following induced abortion in Nnewi, Nigeria.

Science.gov (United States)

Ikechebelu, J I; Okoli, C C

2003-07-01

We present a study of the maternal morbidity and mortality among 76 patients treated at the Nnamdi Azikiwe University Teaching Hospital, Nnewi for complications of induced abortion from January 1996 to December 2000. The total number of maternal admissions over this period was 5750, and illegal induced abortion was responsible for 1.3% of the admissions, with a mortality rate of 5.3% (n = 4) for induced abortion. This accounted for 21.1% of the total maternal deaths (n = 19) for the period. The mean age of the women was 20.6 years (range 15-34 years), 94.7% (n = 72) were unmarried, 93.5% (n = 71) were nulliparous and 76.5% (n = 58) were unemployed, 67.1% (n = 51) had had a mid-trimester termination at > 13 weeks gestational age. It is significant that 55.3% of the patients were teenagers and 45.1% of the mid-trimester abortions occurred in this group. Genital sepsis, haemorrhage, pelvic infection with peritonitis and abscess formation, uterine perforation, and gut injury were the major complications encountered. This study demonstrates that induced abortion is still a major cause of maternal mortality in Nigeria. Integrated family health education, planned parenthood and contraceptive education, a mass literacy campaign and improvement of the existing national health services are recommended in order to ameliorate the problems of illegally induced abortion in Nigeria.

Population Group Abortion Rates and Lifetime Incidence of Abortion: United States, 2008-2014.

Science.gov (United States)

Jones, Rachel K; Jerman, Jenna

2017-12-01

To assess the prevalence of abortion among population groups and changes in rates between 2008 and 2014. We used secondary data from the Abortion Patient Survey, the American Community Survey, and the National Survey of Family Growth to estimate abortion rates. We used information from the Abortion Patient Survey to estimate the lifetime incidence of abortion. Between 2008 and 2014, the abortion rate declined 25%, from 19.4 to 14.6 per 1000 women aged 15 to 44 years. The abortion rate for adolescents aged 15 to 19 years declined 46%, the largest of any group. Abortion rates declined for all racial and ethnic groups but were larger for non-White women than for non-Hispanic White women. Although the abortion rate decreased 26% for women with incomes less than 100% of the federal poverty level, this population had the highest abortion rate of all the groups examined: 36.6. If the 2014 age-specific abortion rates prevail, 24% of women aged 15 to 44 years in that year will have an abortion by age 45 years. The decline in abortion was not uniform across all population groups.

[Demand for abortion. Pre-abortion discussion].

Science.gov (United States)

Guiol, L

1994-03-01

The preabortion interview required by French law takes place between the medical consultation and the aspiration or administration of RU-486. The three marriage counselors at the Center for Social Gynecology in Marseilles have each undertaken a course of personal therapy to enable them to understand their own reactions and motivations as a way of improving their effectiveness with clients. The preabortion interview is an opportunity to listen to and support women who may be experiencing anguish, sadness, ambivalence, or aggressivity. Each client determines the content of the interview. Often the reason for the abortion is given, frequently in terms of economic problems, unemployment, or other justification. The women almost always state that they "cannot", not that they "do not want", to continue the pregnancy, as if external circumstances had made their decision. The decision is usually made with little discussion. Young adolescents are often astounded to find themselves pregnant. Among young girls, the pregnancy may represent an appeal to the parents for attention or understanding. Sometimes the abortion represents a repetition or a reminder of some difficult event in the past, such as a previous abortion or the death of a child. Often the abortion exacerbates problems in the couple's relationship. The mother often experiences rejection of the pregnancy by the father as rejection of herself. Repeat abortions raise questions about whether some aspect of counseling was neglected. The abortion request always occasions a great feeling of guilt, both for being pregnant and for refusing the pregnancy. The interview permits the client to express her feelings and may help her make sense of the experience.

Disparities in abortion experience and access to safe abortion ...

African Journals Online (AJOL)

In Ghana, abortion mortality constitutes 11% of maternal mortality. Empirical studies on possible disparities in abortion experience and access to safe abortion services are however lacking. Based on a retrospective survey of 1,370 women aged 15-49 years in two districts in Ghana, this paper examines disparities in ...

Update on abortion policy.

Science.gov (United States)

Conti, Jennifer A; Brant, Ashley R; Shumaker, Heather D; Reeves, Matthew F

2016-12-01

To review the status of antiabortion restrictions enacted over the last 5 years in the United States and their impact on abortion services. In recent years, there has been an alarming rise in the number of antiabortion laws enacted across the United States. In total, various states in the union enacted 334 abortion restrictions from 2011 to July 2016, accounting for 30% of all abortion restrictions since the legalization of abortion in 1973. Data confirm, however, that more liberal abortion laws do not increase the number of abortions, but instead greatly decrease the number of abortion-related deaths. Several countries including Romania, South Africa and Nepal have seen dramatic decreases in maternal mortality after liberalization of abortion laws, without an increase in the total number of abortions. In the United States, abortions are incredibly safe with very low rates of complications and a mortality rate of 0.7 per 100 000 women. With increasing abortion restrictions, maternal mortality in the United States can be expected to rise over the coming years, as has been observed in Texas recently. Liberalization of abortion laws saves women's lives. The rising number of antiabortion restrictions will ultimately harm women and their families.

Public funding of abortions and abortion counseling for poor women.

Science.gov (United States)

Edwards, R B

1997-01-01

This essay seeks to reveal the weakness in arguments against public funding of abortions and abortion counseling in the US based on economic, ethico-religious, anti-racist, and logical-consistency objections and to show that public funding of abortion is strongly supported by appeals to basic human rights, to freedom of speech, to informed consent, to protection from great harm, to justice, and to equal protection under the law. The first part of the article presents the case against public funding with detailed considerations of the economic argument, the ethico/religious argument, the argument that such funding supports racist genocide or eugenic quality control, and arguments that a logical inconsistency exists between the principles used to justify the legalization of abortions and arguments for public funding. The second part of the article presents the case for public funding by discussing the spending of public funds on morally offensive programs, arguments for public funding of abortion counseling for the poor, and arguments for public funding of abortions for the poor. It is concluded that it is morally unacceptable and rationally unjustifiable to refuse to expend public funds for abortions for low income women, because after all most money for legal abortions for the poor comes from welfare payments made to women. If conservative forces want to insure that no public funds pay for abortions, they must stop all welfare payments to pregnant women.

Accounting for abortion: Accomplishing transnational reproductive governance through post-abortion care in Senegal.

Science.gov (United States)

Suh, Siri

2018-06-01

Reproductive governance operates through calculating demographic statistics that offer selective truths about reproductive practices, bodies, and subjectivities. Post-abortion care, a global reproductive health intervention, represents a transnational reproductive regime that establishes motherhood as women's primary legitimate reproductive status. Drawing on ethnographic fieldwork conducted in Senegal between 2010 and 2011, I illustrate how post-abortion care accomplishes reproductive governance in a context where abortion is prohibited altogether and the US is the primary bilateral donor of population aid. Reproductive governance unfolds in hospital gynecological wards and the national health information system through the mobilization and interpretation of post-abortion care data. Although health workers search women's bodies and behavior for signs of illegal abortion, they minimize police intervention in the hospital by classifying most post-abortion care cases as miscarriage. Health authorities deploy this account of post-abortion care to align the intervention with national and global maternal health policies that valorize motherhood. Although post-abortion care offers life-saving care to women with complications of illegal abortion, it institutionalizes abortion stigma by scrutinizing women's bodies and masking induced abortion within and beyond the hospital. Post-abortion care reinforces reproductive inequities by withholding safe, affordable obstetric care from women until after they have resorted to unsafe abortion.

Efficient identification of phosphatidylserine-binding proteins by ORF phage display

International Nuclear Information System (INIS)

Caberoy, Nora B.; Zhou, Yixiong; Alvarado, Gabriela; Fan, Xianqun; Li, Wei

2009-01-01

To efficiently elucidate the biological roles of phosphatidylserine (PS), we developed open-reading-frame (ORF) phage display to identify PS-binding proteins. The procedure of phage panning was optimized with a phage clone expressing MFG-E8, a well-known PS-binding protein. Three rounds of phage panning with ORF phage display cDNA library resulted in ∼300-fold enrichment in PS-binding activity. A total of 17 PS-binding phage clones were identified. Unlike phage display with conventional cDNA libraries, all 17 PS-binding clones were ORFs encoding 13 real proteins. Sequence analysis revealed that all identified PS-specific phage clones had dimeric basic amino acid residues. GST fusion proteins were expressed for 3 PS-binding proteins and verified for their binding activity to PS liposomes, but not phosphatidylcholine liposomes. These results elucidated previously unknown PS-binding proteins and demonstrated that ORF phage display is a versatile technology capable of efficiently identifying binding proteins for non-protein molecules like PS.

The genomes and comparative genomics of Lactobacillus delbrueckii phages.

Science.gov (United States)

Riipinen, Katja-Anneli; Forsman, Päivi; Alatossava, Tapani

2011-07-01

Lactobacillus delbrueckii phages are a great source of genetic diversity. Here, the genome sequences of Lb. delbrueckii phages LL-Ku, c5 and JCL1032 were analyzed in detail, and the genetic diversity of Lb. delbrueckii phages belonging to different taxonomic groups was explored. The lytic isometric group b phages LL-Ku (31,080 bp) and c5 (31,841 bp) showed a minimum nucleotide sequence identity of 90% over about three-fourths of their genomes. The genomic locations of their lysis modules were unique, and the genomes featured several putative overlapping transcription units of genes. LL-Ku and c5 virions displayed peptidoglycan hydrolytic activity associated with a ~36-kDa protein similar in size to the endolysin. Unexpectedly, the 49,433-bp genome of the prolate phage JCL1032 (temperate, group c) revealed a conserved gene order within its structural genes. Lb. delbrueckii phages representing groups a (a phage LL-H), b and c possessed only limited protein sequence homology. Genomic comparison of LL-Ku and c5 suggested that diversification of Lb. delbrueckii phages is mainly due to insertions, deletions and recombination. For the first time, the complete genome sequences of group b and c Lb. delbrueckii phages are reported.

Phage exposure causes dynamic shifts in the expression states of specific phase-variable genes of Campylobacter jejuni

DEFF Research Database (Denmark)

Aidley, Jack; Holst Sørensen, Martine C.; Bayliss, Christopher D.

2017-01-01

Phase variation (PV) creates phenotypic heterogeneity at high frequencies and in a reversible manner. This phenomenon allows bacteria to adapt to a variety of different environments and selective pressures. In Campylobacter jejuni this reversible adaptive process is mediated by mutations in homop......Phase variation (PV) creates phenotypic heterogeneity at high frequencies and in a reversible manner. This phenomenon allows bacteria to adapt to a variety of different environments and selective pressures. In Campylobacter jejuni this reversible adaptive process is mediated by mutations...... in homopolymeric G/C tracts. Many C. jejuni-specific phages are dependent on phase-variable surface structures for successful infection. We previously identified the capsular polysaccharide (CPS) moiety, MeOPN-GalfNAc, as a receptor for phage F336 and showed that phase-variable expression of the transferase...... for this CPS modification, cj1421, and two other phase-variable CPS genes generated phage resistance in C. jejuni. Here we investigate the population dynamics of C. jejuni NCTC11168 when exposed to phage F336 in vitro using a newly described method - the 28-locus-CJ11168 PV analysis. Dynamic switching...

Consumer attitudes and behaviours--key risk factors in an outbreak of Salmonella typhimurium phage type 12 infection sourced to chicken nuggets.

Science.gov (United States)

Kenny, B; Hall, R; Cameron, S

1999-04-01

To identify the source and intervention methods for an outbreak of Salmonella Typhimurium phage type 12 in South Australia. Ten cases of S. Typhimurium phage type (PT) 12 infection were notified in South Australia in a four-week period from 7 May 1998. Nine cases and 27 controls were included in a case control study to test the hypothesis that illness was associated with the consumption of chicken nuggets. A significant association between illness and the consumption of one brand of chicken nuggets was determined, odds ratio undefined (95% CI undefined; p = undefined). Nine of nine cases and one of 27 controls reported eating these chicken nuggets. S. Typhimurium PT 12 was isolated from an opened sample of this particular brand of nuggets which had been retrieved from the home of one case. The implicated nuggets were essentially a raw product which had been 'flash fried' in contrast with other brands which were fully cooked. The investigation highlighted issues of inadequate labelling and consumer responses to labelling information which affect food safety. A media release to highlight to the consumer the need to cook frozen food properly and a voluntary recall of the 'flash fried' product was instigated as a result of these conclusions. Further action is needed to eliminate the potential hazard that consumers will perceive and handle 'flash fried' nuggets as if they are a cooked chicken product.

Trying to prevent abortion.

Science.gov (United States)

Bromham, D R; Oloto, E J

1997-06-01

It is known that, since antiquity, women confronted with an unwanted pregnancy have used abortion as a means of resolving their dilemma. Although undoubtedly widely used in all historical ages, abortion has come to be regarded as an event preferably avoided because of the impact on the women concerned as well as considerations for fetal life. Policies to reduce numbers and rates of abortion must acknowledge certain observations. Criminalization does not prevent abortion but increases maternal risks. A society's 'openness' in discussing sexual matters inversely correlates with abortion rates. Correlation between contraceptive use and abortion is also inverse but relates most closely to the efficacy of contraceptive methods used. 'Revolution' in the range of contraceptive methods used will have an equivalent impact on abortion rates. Secondary or emergency contraceptive methods have a considerable role to play in the reduction of abortion numbers. Good sex (and 'relationships') education programs may delay sexual debut, increase contraceptive usage and be associated with reduced abortion. Finally, interaction between socioeconomic factors and the choice between abortion and ongoing pregnancy are complex. Abortion is not necessarily chosen by those least able to support a child financially.

Morphological evidence for phages in Xylella fastidiosa

Directory of Open Access Journals (Sweden)

Civerolo Edwin L

2008-06-01

Full Text Available Abstract Presumptive phage particles associated with Xylella fastidiosa strain Temecula-1 grown in PW broth were observed by transmission electron microscopy (TEM in ultrathin sections of bacterial cell-containing low speed centrifugation pellets and in partially purified preparations from CsCl equilibrium centrifugation density gradients. Ultrathin-sectioned cell pellets contained icosahedral particles of about 45 nm in diameter. Samples collected from CsCl density gradients revealed mostly non-tailed icosahedral but also tailed particles. The icosahedral particles could be divided into two types: a large type (about 45 nm and a small type (about 30 nm. Filamentous phage-like particles (17 × 120 to 6,300 nm were also observed. The presence of different types of phage-like particles resembling to those in several bacteriophage families provides new physical evidence, in addition to X. fastidiosa genomic information, that X. fastidiosa possesses active phages. This is the first report of phage particles released in X. fastidiosa cultures.

Structural Conservation of the Myoviridae Phage Tail Sheath Protein Fold

Energy Technology Data Exchange (ETDEWEB)

Aksyuk, Anastasia A.; Kurochkina, Lidia P.; Fokine, Andrei; Forouhar, Farhad; Mesyanzhinov, Vadim V.; Tong, Liang; Rossmann, Michael G. (SOIBC); (Purdue); (Columbia)

2012-02-21

Bacteriophage phiKZ is a giant phage that infects Pseudomonas aeruginosa, a human pathogen. The phiKZ virion consists of a 1450 {angstrom} diameter icosahedral head and a 2000 {angstrom}-long contractile tail. The structure of the whole virus was previously reported, showing that its tail organization in the extended state is similar to the well-studied Myovirus bacteriophage T4 tail. The crystal structure of a tail sheath protein fragment of phiKZ was determined to 2.4 {angstrom} resolution. Furthermore, crystal structures of two prophage tail sheath proteins were determined to 1.9 and 3.3 {angstrom} resolution. Despite low sequence identity between these proteins, all of these structures have a similar fold. The crystal structure of the phiKZ tail sheath protein has been fitted into cryo-electron-microscopy reconstructions of the extended tail sheath and of a polysheath. The structural rearrangement of the phiKZ tail sheath contraction was found to be similar to that of phage T4.

Supersize me: Cronobacter sakazakii phage GAP32

Energy Technology Data Exchange (ETDEWEB)

Abbasifar, Reza; Griffiths, Mansel W. [Canadian Research Institute for Food Safety, University of Guelph, Guelph, ON, Canada N1G 2W1 (Canada); Sabour, Parviz M. [Agriculture and Agri-Food Canada, Guelph Food Research Centre, Guelph, ON, Canada N1G 5C9 (Canada); Ackermann, Hans-Wolfgang [Department of Microbiology-Infectiology and Immunology, Faculty of Medicine, Université Laval, Quebec, QC (Canada); Vandersteegen, Katrien; Lavigne, Rob [Laboratory of Gene Technology, Katholieke Universiteit Leuven, Leuven (Belgium); Noben, Jean-Paul [Biomedical Research Institute and Transnational University Limburg, School of Life Sciences, Hasselt University, Diepenbeek (Belgium); Alanis Villa, Argentina; Abbasifar, Arash [Canadian Research Institute for Food Safety, University of Guelph, Guelph, ON, Canada N1G 2W1 (Canada); Nash, John H.E. [Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, ON, Canada N1G 3W4 (Canada); Kropinski, Andrew M., E-mail: akropins@uoguelph.ca [Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, ON, Canada N1G 3W4 (Canada); Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1 (Canada)

2014-07-15

Cronobacter sakazakii is a Gram-negative pathogen found in milk-based formulae that causes infant meningitis. Bacteriophages have been proposed to control bacterial pathogens; however, comprehensive knowledge about a phage is required to ensure its safety before clinical application. We have characterized C. sakazakii phage vB{sub C}saM{sub G}AP32 (GAP32), which possesses the second largest sequenced phage genome (358,663 bp). A total of 571 genes including 545 protein coding sequences and 26 tRNAs were identified, thus more genes than in the smallest bacterium, Mycoplasma genitalium G37. BLASTP and HHpred searches, together with proteomic analyses reveal that only 23.9% of the putative proteins have defined functions. Some of the unique features of this phage include: a chromosome condensation protein, two copies of the large subunit terminase, a predicted signal-arrest-release lysin; and an RpoD-like protein, which is possibly involved in the switch from immediate early to delayed early transcription. Its closest relatives are all extremely large myoviruses, namely coliphage PBECO4 and Klebsiella phage vB{sub K}leM-RaK2, with whom it shares approximately 44% homologous proteins. Since the homologs are not evenly distributed, we propose that these three phages belong to a new subfamily. - Highlights: • Cronobacter sakazakii phage vB{sub C}saM{sub G}AP32 has a genome of 358,663 bp. • It encodes 545 proteins which is more than Mycoplasma genitalium G37. • It is a member of the Myoviridae. • It is peripherally related to coliphage PBECO4 and Klebsiella phage vB{sub K}leM-RaK2. • GAP32 encodes a chromosome condensation protein.

[Abortion].

Science.gov (United States)

Nunes, J P

1998-01-01

Abortion is the interruption of a dynamic process in a final and irreversible form. The legalization of abortion is applied to human ontogenesis, that is, the development of the human being. However, the embryo that is growing in the uterus is not a human being because a human being is a complex organism with differentiated systems, its own identity and intrinsic autonomy in its process of development. There are basically four levels of the analysis of the problem of abortion: 1) fundamental emotional arguments; 2) profound ignorance of technical and scientific facts; 3) rational positions obfuscated by the dramatic intensity of everyday situations; and 4) the conjunction of deliberated position where culpability is avoided with solidarity for all subjects of the process with a socially oriented view. The phenomenon of abortion from an epidemiological point of view summons the facts with which it is associated: poverty, illiteracy, shortage or lack of community health resources, absence of centers for adolescents, degradation of the environment, and precariousness of employment.

[Use of contraception and reasons for choosing abortion among abortion applicants].

Science.gov (United States)

Hansen, S K; Birkebaek, J S; Husfeldt, C; Munck, C B; Nøddebo, S M; Petersson, B H

1996-10-07

The object of this study was to describe a group of women applying for legal abortion in relation to their use of contraception and reasons for choosing an abortion. During a period of 13 months (1991-92) a questionnaire was distributed to women applying for legal abortion at Hillerød Hospital in Denmark. Three hundred and thirty-nine women participated. Fifty-nine percent of the women had become pregnant although they had used contraception. As seen in other studies, women still state demographic factors as their most important reasons for choosing an abortion. Women with two or more children do not want to have more children. Single women do not want children without being in a stable relationship. Furthermore occupation and education were frequently stated as important reasons for having an abortion. Economy and housing were not main reasons but contributory factors. Thirty percent of the women expressed ambivalence about the choice of abortion at the time when the abort was due.

Post-abortion and induced abortion services in two public hospitals in Colombia.

Science.gov (United States)

Darney, Blair G; Simancas-Mendoza, Willis; Edelman, Alison B; Guerra-Palacio, Camilo; Tolosa, Jorge E; Rodriguez, Maria I

2014-07-01

Until 2006, legal induced abortion was completely banned in Colombia. Few facilities are equipped or willing to offer abortion services; often adolescents experience even greater barriers of access in this context. We examined post abortion care (PAC) and legal induced abortion in two large public hospitals. We tested the association of hospital site, procedure type (manual vacuum aspiration vs. sharp curettage), and age (adolescents vs. women 20 years and over) with service type (PAC or legal induced abortion). Retrospective cohort study using 2010 billing data routinely collected for reimbursement (N=1353 procedures). We utilized descriptive statistics, multivariable logistic regression and predicted probabilities. Adolescents made up 22% of the overall sample (300/1353). Manual vacuum aspiration was used in one-third of cases (vs. sharp curettage). Adolescents had lower odds of documented PAC (vs. induced abortion) compared with women over age 20 (OR=0.42; 95% CI=0.21-0.86). The absolute difference of service type by age, however, is very small, controlling for hospital site and procedure type (.97 probability of PAC for adolescents compared with .99 for women 20 and over). Regardless of age, PAC via sharp curettage is the current standard in these two public hospitals. Both adolescents and women over 20 are in need of access to legal abortion services utilizing modern technologies in the public sector in Colombia. Documentation of abortion care is an essential first step to determining barriers to access and opportunities for quality improvement and better health outcomes for women. Following partial decriminalization of abortion in Colombia, in public hospitals nearly all abortion services are post-abortion care, not induced abortion. Sharp curettage is the dominant treatment for both adolescents and women over 20. Women seek care in the public sector for abortion, and must have access to safe, quality services. Copyright © 2014. Published by Elsevier Inc.

[Bioethics and abortion. Debate].

Science.gov (United States)

Diniz, D; Gonzalez Velez, A C

1998-06-01

Although abortion has been the most debated of all issues analyzed in bioethics, no moral consensus has been achieved. The problem of abortion exemplifies the difficulty of establishing social dialogue in the face of distinct moral positions, and of creating an independent academic discussion based on writings that are passionately argumentative. The greatest difficulty posed by the abortion literature is to identify consistent philosophical and scientific arguments amid the rhetorical manipulation. A few illustrative texts were selected to characterize the contemporary debate. The terms used to describe abortion are full of moral meaning and must be analyzed for their underlying assumptions. Of the four main types of abortion, only 'eugenic abortion', as exemplified by the Nazis, does not consider the wishes of the woman or couple--a fundamental difference for most bioethicists. The terms 'selective abortion' and 'therapeutic abortion' are often confused, and selective abortion is often called eugenic abortion by opponents. The terms used to describe abortion practitioners, abortion opponents, and the 'product' are also of interest in determining the style of the article. The video entitled "The Silent Scream" was a classic example of violent and seductive rhetoric. Its type of discourse, freely mixing scientific arguments and moral beliefs, hinders analysis. Within writings about abortion three extreme positions may be identified: heteronomy (the belief that life is a gift that does not belong to one) versus reproductive autonomy; sanctity of life versus tangibility of life; and abortion as a crime versus abortion as morally neutral. Most individuals show an inconsistent array of beliefs, and few groups or individuals identify with the extreme positions. The principal argument of proponents of legalization is respect for the reproductive autonomy of the woman or couple based on the principle of individual liberty, while heteronomy is the main principle of

A novel lineage of myoviruses infecting cyanobacteria is widespread in the oceans.

Science.gov (United States)

Sabehi, Gazalah; Shaulov, Lihi; Silver, David H; Yanai, Itai; Harel, Amnon; Lindell, Debbie

2012-02-07

Viruses infecting bacteria (phages) are thought to greatly impact microbial population dynamics as well as the genome diversity and evolution of their hosts. Here we report on the discovery of a novel lineage of tailed dsDNA phages belonging to the family Myoviridae and describe its first representative, S-TIM5, that infects the ubiquitous marine cyanobacterium, Synechococcus. The genome of this phage encodes an entirely unique set of structural proteins not found in any currently known phage, indicating that it uses lineage-specific genes for virion morphogenesis and represents a previously unknown lineage of myoviruses. Furthermore, among its distinctive collection of replication and DNA metabolism genes, it carries a mitochondrial-like DNA polymerase gene, providing strong evidence for the bacteriophage origin of the mitochondrial DNA polymerase. S-TIM5 also encodes an array of bacterial-like metabolism genes commonly found in phages infecting cyanobacteria including photosynthesis, carbon metabolism and phosphorus acquisition genes. This suggests a common gene pool and gene swapping of cyanophage-specific genes among different phage lineages despite distinct sets of structural and replication genes. All cytosines following purine nucleotides are methylated in the S-TIM5 genome, constituting a unique methylation pattern that likely protects the genome from nuclease degradation. This phage is abundant in the Red Sea and S-TIM5 gene homologs are widespread in the oceans. This unusual phage type is thus likely to be an important player in the oceans, impacting the population dynamics and evolution of their primary producing cyanobacterial hosts.

Complete Genome Sequence of the Novel Bacteriophage pSco-10 Infecting Staphylococcus cohnii

OpenAIRE

Jun, Jin Woo; Giri, Sib Sankar; Kim, Hyoun Joong; Chi, Cheng; Yun, Saekil; Kim, Sang Guen; Kim, Sang Wha; Kang, Jeong Woo; Park, Se Chang

2017-01-01

ABSTRACT Herein, we report the complete genome sequence of the Staphylococcus Myoviridae phage pSco-10 infecting Staphylococcus cohnii. The phage pSco-10 was isolated from duck feces collected from four farms in South Korea. The current report provides valuable information for genomic study of phages.

Abortion Before & After Roe

Science.gov (United States)

Joyce, Ted; Tan, Ruoding; Zhang, Yuxiu

2013-01-01

We use unique data on abortions performed in New York State from 1971–1975 to demonstrate that women travelled hundreds of miles for a legal abortion before Roe. A100- mile increase in distance for women who live approximately 183 miles from New York was associated with a decline in abortion rates of 12.2 percent whereas the same change for women who lived 830 miles from New York lowered abortion rates by 3.3 percent. The abortion rates of nonwhites were more sensitive to distance than those of whites. We found a positive and robust association between distance to the nearest abortion provider and teen birth rates but less consistent estimates for other ages. Our results suggest that even if some states lost all abortion providers due to legislative policies, the impact on population measures of birth and abortion rates would be small as most women would travel to states with abortion services. PMID:23811233

Trends of abortion complications in a transition of abortion law revisions in Ethiopia.

Science.gov (United States)

Gebrehiwot, Yirgu; Liabsuetrakul, Tippawan

2009-03-01

Evidence from developed countries has shown that abortion-related mortality and morbidity has decreased with the liberalization of the abortion law. This study aimed to assess the trend of hospital-based abortion complications during the transition of legalization in Ethiopia in May 2005. Medical records of women with abortion complications from 2003 to 2007 were reviewed (n = 773). Abortion and its complications with regard to legalization were described by rates and ratios, and predictors of fatal outcomes were analyzed by logistic regression. The overall and abortion-related maternal mortality ratios (AMMRs) showed a non-statistically significant downward trend over the 5-year period. However, the case fatality rate of abortion increased from 1.1% in 2003 to 3.6% in 2007. Late gestational age, history of interference and presenting after new abortion legislation passed have been found to be significant predictors of mortality. Decreased trends of abortion ratio and the AMMR were identified, but the severity of abortion complications and the case fatality rate increased during the transition of legal revision.

[Construction of a phage antibody library and screening of anti-epidermal growth factor receptor variant III single chain antibody].

Science.gov (United States)

Han, Dong-gang; Duan, Xiao-yi; Guo, You-min; Zhou, Qi; Wang, Quan-ying; Yang, Guang-xiao

2010-01-01

To obtain specific anti-epidermal growth factor receptor variant III (EGFRvIII) single chain antibody (ScFv) by phage antibody library display system. The total RNA was extracted from the spleen B cells of BALB/c mice immunized with pep-3-OVA protein, and the first-strand cDNA was synthesized by reverse transcription. Antibody VH and VL gene fragments were amplified and joined to a ScFv gene with the linker. The ScFv gene was ligated into the phagemid vector pCANTAB5E, which was transformed into competent E. coli TG1. The transformed cells were then infected with M13KO7 helper phage to yield the recombinant phage to construct the phage ScFv library. Pep-3-BSA protein was used to screen the phage antibody library and ELISA carried out to characterize the activity of the antibody. The VH and VL gene fragments of the antibody were about 350 bp and 320 bp in length as analyzed by agarose gel electrophoresis. The ScFv gene was 780 bp, consistent with the expected length. The recombinant phagemid with ScFv gene insert was rescued, and an immune phage ScFv library with the content of 5.0x10(6) was constructed. The recombinant ScFv phage had a titer of 3.0x10(4) cfu/ml, and the fourth phage harvest yielded 56 times as much as that of the first one. SDS-PAGE demonstrated a molecular mass of the soluble ScFv of about 28 kD. ELISA results indicated good specificity of the ScFv to bind EGFRvIII. An immune phage ScFv library is successfully constructed, and the ScFv antibody fragment is capable of specific binding to EGFRvIII.

The incidence of abortion worldwide.

Science.gov (United States)

Henshaw, S K; Singh, S; Haas, T

1999-01-01

Accurate measurement of induced abortion levels has proven difficult in many parts of the world. Health care workers and policymakers need information on the incidence of both legal and illegal induced abortion to provide the needed services and to reduce the negative impact of unsafe abortion on women's health. Numbers and rates of induced abortions were estimated from four sources: official statistics or other national data on legal abortions in 57 countries; estimates based on population surveys for two countries without official statistics; special studies for 10 countries where abortion is highly restricted; and worldwide and regional estimates of unsafe abortion from the World Health Organization. Approximately 26 million legal and 20 million illegal abortions were performed worldwide in 1995, resulting in a worldwide abortion rate of 35 per 1,000 women aged 15-44. Among the subregions of the world, Eastern Europe had the highest abortion rate (90 per 1,000) and Western Europe to the lowest rate (11 per 1,000). Among countries where abortion is legal without restriction as to reason, the highest abortion rate, 83 per 1,000, was reported for Vietnam and the lowest, seven per 1,000, for Belgium and the Netherlands. Abortion rates are no lower overall in areas where abortion is generally restricted by law (and where many abortions are performed under unsafe conditions) than in areas where abortion is legally permitted. Both developed and developing countries can have low abortion rates. Most countries, however, have moderate to high abortion rates, reflecting lower prevalence and effectiveness of contraceptive use. Stringent legal restrictions do not guarantee a low abortion rate.

Characterisation of a novel enterobacteria phage, CAjan, isolated from rat faeces.

Science.gov (United States)

Carstens, Alexander B; Kot, Witold; Lametsch, Rene; Neve, Horst; Hansen, Lars H

2016-08-01

In this study, we describe the isolation and characterisation of the novel enterobacteria phage CAjan. This phage belongs to the order Caudovirales and the family Siphoviridae. The phage possesses a linear, double-stranded DNA genome consisting of 59,670 bp with a G+C content of 44.7 % and 91 predicted open reading frames (ORFs). Putative functions were assigned to 39 of the ORFs (37.4 %). The phage structural genes were furthermore functionally characterised by LC MS/MS. CAjan, together with Escherichia phage Seurat and Escherichia phage slur01, represent a novel and genetically distinct clade of Siphoviridae phages that could be considered to constitute a new phage genus. Despite limited sequence similarity, the phages in this group share a number of other common features, including genome structure and the presence of queuosine biosynthesis genes.

[[Abortion: An Unforgivable Sin?].

Science.gov (United States)

Lalli, Chiara

Abortion has become something to hide, something you can't tell other people, something you have to expiate forever. Besides, abortion is more and more difficult to achieve because of the raising average of consciencious objection (from 70 to 90% of health care providers are conscientious objectors, 2014 data, Ministero della Salute) and illegal abortion is "coming back"from the 70s, when abortion was a crime (Italian law n. 194/1978). Abortion is often blamed as a murder, an unforgivenable sin, even as genocide. Silence against shouting "killers!" to women who are going to have an abortion: this is a common actual scenario. Why is it so difficult to discuss and even to mention abortion?

Misoprostol for treatment of incomplete abortion- providers practice ...

African Journals Online (AJOL)

Remnant products of conception in the uterine cavity following a miscarriage or induced abortion presents a serious threat to a woman because it increases the risk of infection or continued bleeding and therefore uterine evacuation in such cases is imperative. Surgical and medical methods using drugs like misoprostol may ...

Advanced Analysis to Distinguish between Physical Decrease and Inactivation of Viable Phages in Aerosol by Quantitating Phage-Specific Particles.

Science.gov (United States)

Shimasaki, Noriko; Nojima, Yasuhiro; Sakakibara, Masaya; Kikuno, Ritsuko; Iizuka, Chiori; Okaue, Akira; Okuda, Shunji; Shinohara, Katsuaki

2018-01-01

　Recent studies have investigated the efficacy of air-cleaning products against pathogens in the air. A standard method to evaluate the reduction in airborne viruses caused by an air cleaner has been established using a safe bacteriophage instead of pathogenic viruses; the reduction in airborne viruses is determined by counting the number of viable airborne phages by culture, after operating the air cleaner. The reduction in the number of viable airborne phages could be because of "physical decrease" or "inactivation". Therefore, to understand the mechanism of reduction correctly, an analysis is required to distinguish between physical decrease and inactivation. The purpose of this study was to design an analysis to distinguish between the physical decrease and inactivation of viable phi-X174 phages in aerosols. We established a suitable polymerase chain reaction (PCR) system by selecting an appropriate primer-probe set for PCR and validating the sensitivity, linearity, and specificity of the primer-probe set to robustly quantify phi-X174-specific airborne particles. Using this quantitative PCR system and culture assay, we performed a behavior analysis of the phage aerosol in a small chamber (1 m 3 ) at different levels of humidity, as humidity is known to affect the number of viable airborne phages. The results revealed that the reduction in the number of viable airborne phages was caused not only by physical decrease but also by inactivation under particular levels of humidity. Our study could provide an advanced analysis to differentiate between the physical decrease and inactivation of viable airborne phages.

Therapeutic use of chimeric bacteriophage (phage) lysins in staphylococcal endophthalmitis

Science.gov (United States)

Purpose: Phage endolysins are peptidoglycan hydrolases that are produced at the end of the phage lytic cycle to digest the host bacterial cell wall, facilitating the release of mature phage progeny. The aim of this study is to determine the antimicrobial activity of chimeric phage lysins against cli...

Challenges and Future Prospects of Antibiotic Therapy: From Peptides to Phages Utilization

Directory of Open Access Journals (Sweden)

Santi M. Mandal

2014-05-01

Full Text Available Bacterial infections are raising serious concern across the globe. The effectiveness of conventional antibiotics is decreasing due to global emergence of multi-drug-resistant (MDR bacterial pathogens. This process seems to be primarily caused by an indiscriminate and inappropriate use of antibiotics in non-infected patients and in the food industry. New classes of antibiotics with different actions against MDR pathogens need to be developed urgently. In this context, this review focuses on several ways and future directions to search for the next generation of safe and effective antibiotics compounds including antimicrobial peptides, phage therapy, phytochemicals, metalloantibiotics, LPS and efflux pump inhibitors to control the infections caused by MDR pathogens.

Isolation and characterization of numerous novel phages targeting diverse strains of the ubiquitous and opportunistic pathogen Achromobacter xylosoxidans.

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Johannes Wittmann

Full Text Available The clinical relevance of nosocomially acquired infections caused by multi-resistant Achromobacter strains is rapidly increasing. Here, a diverse set of 61 Achromobacter xylosoxidans strains was characterized by MultiLocus Sequence Typing and Phenotype MicroArray technology. The strains were further analyzed in regard to their susceptibility to 35 antibiotics and to 34 different and newly isolated bacteriophages from the environment. A large proportion of strains were resistant against numerous antibiotics such as cephalosporines, aminoglycosides and quinolones, whereas piperacillin-tazobactam, ticarcillin, mezlocillin and imipenem were still inhibitory. We also present the first expanded study on bacteriophages of the genus Achromobacter that has been so far a blank slate with respect to phage research. The phages were isolated mainly from several waste water treatment plants in Germany. Morphological analysis of all of these phages by electron microscopy revealed a broad diversity with different members of the order Caudovirales, including the families Siphoviridae, Myoviridae, and Podoviridae. A broad spectrum of different host ranges could be determined for several phages that lysed up to 24 different and in part highly antibiotic resistant strains. Molecular characterisation by DNA restriction analysis revealed that all phages contain linear double-stranded DNA. Their restriction patterns display distinct differences underlining their broad diversity.

Pattern of Microbial Flora in Septic Incomplete Abortion in Port ...

African Journals Online (AJOL)

Alasia Datonye

organisms present in the endocervix and posterior vaginal fornix in 150 women with ... cultured in septic abortion in this environment. The infections are usually ... These are both major hospitals offering tertiary care in Port. Harcourt the capital ...

Outbreak of Salmonella Dublin-associated abortion in Danish fur farms

DEFF Research Database (Denmark)

Dietz, Hans Henrich; Chriél, Mariann; Andersen, Thomas Holmen

2006-01-01

Outbreaks of Salmonella Dublin infections were recorded in 25 Danish mink and fox farms. All farms suffered extensive disease problems; clinical and pathological observations included abortion, stillbirths, necrotizing endometritis, and increased mortality. By genotyping with pulsed-field gel...

Typing of Panton-Valentine leukocidin-encoding phages carried by methicillin-susceptible and methicillin-resistant Staphylococcus aureus from Italy.

Science.gov (United States)

Sanchini, A; Del Grosso, M; Villa, L; Ammendolia, M G; Superti, F; Monaco, M; Pantosti, A

2014-11-01

Panton-Valentine leukocidin (PVL) is the hallmark of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) but can also be found in methicillin-susceptible S. aureus (MSSA) sharing pathogenic and epidemiological characteristics of CA-MRSA. PVL is encoded by two co-transcribed genes that are carried by different staphylococcal bacteriophages. We applied an extended PCR-based typing scheme for the identification of two morphological groups (elongated-head group and icosahedral-head group I phages) and specific PVL phage types in S. aureus isolates recovered in Italy. We examined 48 PVL-positive isolates (25 MSSA and 23 MRSA) collected from different hospital laboratories from April 2005 to May 2011. spa typing, multilocus sequence typing and staphylococcal cassette chromosome mec typing were applied to categorize the isolates. Phage typeability was 48.0% in MSSA and 91.3% in MRSA, highlighting the limitation of the PCR typing scheme when applied to PVL-positive MSSA. Five different PVL phages and two variants of a known phage were detected, the most prevalent being ΦSa2usa, recovered in 15 out of 48 (31.2%) isolates, and carried by both MSSA and MRSA belonging to CC8 and CC5. The recently described ΦTCH60 was recovered in four isolates. A PVL phage (ΦSa119) from an ST772 MRSA, that was not detected using the previous typing scheme, was sequenced, and new primers were designed for the identification of the icosahedral-head group II PVL phages present in ST772 and ST59 MRSA. A comprehensive PVL-phage typing can contribute to the understanding of the epidemiology and evolution of PVL-positive MSSA and MRSA. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

In Vivo Imaging of Molecularly Targeted Phage

Directory of Open Access Journals (Sweden)

Kimberly A. Kelly

2006-12-01

Full Text Available Rapid identification of in vivo affinity ligands would have far-reaching applications for imaging specific molecular targets, in vivo systems imaging, and medical use. We have developed a high-throughput method for identifying and optimizing ligands to map and image biologic targets of interest in vivo. We directly labeled viable phage clones with far-red fluorochromes and comparatively imaged them in vivo by multichannel fluorescence ratio imaging. Using Secreted Protein Acidic and Rich in Cysteine (osteonectin and vascular cell adhesion molecule-1 as model targets, we show that: 1 fluorescently labeled phage retains target specificity on labeling; 2 in vivo distribution can be quantitated (detection thresholds of ~ 300 phage/mm3 tissue throughout the entire depth of the tumor using fluorescent tomographic imaging; and 3 fluorescently labeled phage itself can serve as a replenishable molecular imaging agent. The described method should find widespread application in the rapid in vivo discovery and validation of affinity ligands and, importantly, in the use of fluorochrome-labeled phage clones as in vivo imaging agents.

Detection of cytomegalovirus, human parvovirus B19, and herpes simplex virus-1/2 in women with first-trimester spontaneous abortions.

Science.gov (United States)

Zhou, Ya; Bian, Guohui; Zhou, Qiongxiu; Gao, Zhan; Liao, Pu; Liu, Yu; He, Miao

2015-10-01

The relationship between viral infections and first-trimester spontaneous abortions is not well-understood. The study aim was to investigate the prevalence of cytomegalovirus (CMV), human parvovirus B19 (B19V), and herpes simplex virus-1/2 (HSV-1/2) infection by molecular and serological techniques in women experiencing spontaneous miscarriage in the first trimester of pregnancy. Plasma samples were examined for CMV, B19V, and HSV-1/2 DNA using real-time quantitative polymerase chain reaction (Real-time qPCR), and for specific IgG antibodies against B19V, CMV, and HSV-1/2 using serological assays. The abortion group consisted of women (n = 1,716) with a history of two or more first-trimester spontaneous abortions. Women younger than 30 years possess higher portion to experience spontaneous abortion. No specimens were positive for B19V or CMV DNA. Seven out of the 1,716 specimens were positive for HSV-1/2 DNA. By serology, 47.24% of patients were positive for B19V IgG, 39.66% for HSV IgG, 79.31% for CMV IgG, and 9.31% for B19V IgM. The high rate of positivity for CMV IgG suggests that the majority of women with first-trimester spontaneous abortions are not susceptible to primary CMV infection. The lack of virus DNA in the majority of cases indicates that B19V, CMV, and HSV-1/2 infection is not commonly associated with first-trimester spontaneous abortion. © 2015 Wiley Periodicals, Inc.

Telling stories about abortion: abortion-related plots in American film and television, 1916-2013.

Science.gov (United States)

Sisson, Gretchen; Kimport, Katrina

2014-05-01

Popular discourse on abortion in film and television assumes that abortions are under- and misrepresented. Research indicates that such representations influence public perception of abortion care and may play a role in the production of social myths around abortion, with consequences for women's experience of abortion. To date, abortion plotlines in American film and television have not been systematically tracked and analyzed. A comprehensive online search was conducted to identify all representations of pregnancy decision making and abortion in American film and television through January 2013. Search results were coded for year, pregnancy decision and mortality outcome. A total of 310 plotlines were identified, with an overall upward trend over time in the number of representations of abortion decision making. Of these plotlines, 173 (55.8%) resulted in abortion, 80 (25.8%) in parenting, 13 (4.2%) in adoption and 21 (6.7%) in pregnancy loss, and 16 (5.1%) were unresolved. A total of 13.5% (n=42) of stories ended with the death of the woman who considered an abortion, whether or not she obtained one. Abortion-related plotlines occur more frequently than popular discourse assumes. Year-to-year variation in frequency suggests an interactive relationship between media representations, cultural attitudes and policies around abortion regulation, consistent with cultural theory of the relationship between media products and social beliefs. Patterns of outcomes and rates of mortality are not representative of real experience and may contribute to social myths around abortion. The narrative linking of pregnancy termination with mortality is of particular note, supporting the social myth associating abortion with death. This analysis empirically describes the number of abortion-related plotlines in American film and television. It contributes to the systematic evaluation of the portrayal of abortion in popular culture and provides abortion care professionals and

How to Name and Classify Your Phage: An Informal Guide

Directory of Open Access Journals (Sweden)

Evelien Adriaenssens

2017-04-01

Full Text Available With this informal guide, we try to assist both new and experienced phage researchers through two important stages that follow phage discovery; that is, naming and classification. Providing an appropriate name for a bacteriophage is not as trivial as it sounds, and the effects might be long-lasting in databases and in official taxon names. Phage classification is the responsibility of the Bacterial and Archaeal Viruses Subcommittee (BAVS of the International Committee on the Taxonomy of Viruses (ICTV. While the BAVS aims at providing a holistic approach to phage taxonomy, for individual researchers who have isolated and sequenced a new phage, this can be a little overwhelming. We are now providing these researchers with an informal guide to phage naming and classification, taking a “bottom-up” approach from the phage isolate level.

A prospective self-controlled study of fertility after second-trimester prostaglandin-induced abortion.

Science.gov (United States)

MacKenzie, I Z; Fry, A

1988-05-01

One hundred forty women whose pregnancies were terminated in the second trimester with prostaglandins because of suspected fetal disease have been prospectively followed to assess their subsequent fertility. In six instances difficulties had been experienced in conceiving the pregnancy that was terminated. Since abortion 104 women have conceived, 97% within 24 months of abortion but in five instances after some delay. Only one woman had not succeeded in conceiving a wished-for pregnancy. There were no apparent differences in abortion management between those women readily conceiving and those in whom there was some delay, although termination because of chromosomal reasons or anatomic abnormalities was less commonly followed by another pregnancy as compared with those terminated for rubella or other viral infections. Reduced fertility after a late prostaglandin-induced abortion thus appears to be very infrequent.

Bowel injuries secondary to induced abortion: a dilemma

International Nuclear Information System (INIS)

Rehman, A.; Fatima, S.; Soomro, N.

2006-01-01

To study the pattern of bowel injuries incurred by induced abortion, and the morbidity and mortality associated with them. All patients with bowel injuries due to induced abortion. Detailed data of all the patients was collected and analyzed. A total of 22 patients, mostly young with an average age of 26.86 years, presented with bowel injuries following induced abortion. Severe hemorrhage occurred in 8(36.4%) patients while 11(50%) had ileal perforation; 9(40.9%) underwent primary repair and 2(9.1%) ileostomy formation. Two (9.1%) patients with jejunal perforation had primary repair, whereas two with both jejunal and ileal perforations underwent resections with anastomosis in one and ileostomy in another. Seven (31.8%) with large gut involvement had colostomy formation. Septicemia and wound infection occurred in 7(31.8%) patients each, faecal fistula and abdominal wound dehiscence in 3(13.6%), and pelvic abscess in 1(4.6%) patient. The total mortality in this series was 6(27.3%) patients. Iatrogenic injuries during induced abortion, most commonly caused by quacks, can be minimized substantially if the procedure is performed by qualified medical personnel in proper health care facilities. There is a need for radical overhauling of the mind set in our society together with legislation. (author)

Mutagenesis of lambda phage by tif-expression or host-irradiation functions is largely independent of damage in the phage DNA

International Nuclear Information System (INIS)

Von Wright, A.; Bridges, B.A.

1980-01-01

The survival and mutagenesis of UV-irradiated phage lambda, as well as bacterial mutagenesis, are enhanced in tif mutants of Escherichia coli when these strains are grown at 43 0 C (Castellazzi et al., 1972). This was interpreted on the basis of a hypothesis (the SOS hypothesis) according to which the UV-inducible phenomena connected with reactivation and mutagenesis of UV-irradiated bacteriophages (Weigle, 1953; Radman, 1975) are constitutively expressed in tif-bacteria at high temperature (Witkin, 1974). In unpublished experiments with phage T3 we found that the survival of UV-irradiated phage is also better at 43 0 C than at 32 0 C in tif + cells and this made us reexamine the significance and nature of tif expression and examine its effects on both unirradiated and UV-irradiated phage lambda. Our results indicate that tif-induced mutagenesis and possibly reactivation of UV-irradiated phage lambda should be reinterpreted. (orig./AJ)

Estimates of the Incidence of Induced Abortion And Consequences of Unsafe Abortion in Senegal

Science.gov (United States)

Sedgh, Gilda; Sylla, Amadou Hassane; Philbin, Jesse; Keogh, Sarah; Ndiaye, Salif

2015-01-01

CONTEXT Abortion is highly restricted by law in Senegal. Although women seek care for abortion complications, no national estimate of abortion incidence exists. METHODS Data on postabortion care and abortion in Senegal were collected in 2013 using surveys of a nationally representative sample of 168 health facilities that provide postabortion care and of 110 professionals knowledgeable about abortion service provision. Indirect estimation techniques were applied to the data to estimate the incidence of induced abortion in the country. Abortion rates and ratios were calculated for the nation and separately for the Dakar region and the rest of the country. The distribution of pregnancies by planning status and by outcome was estimated. RESULTS In 2012, an estimated 51,500 induced abortions were performed in Senegal, and 16,700 (32%) resulted in complications that were treated at health facilities. The estimated abortion rate was 17 per 1,000 women aged 15–44 and the abortion ratio was 10 per 100 live births. The rate was higher in Dakar (21 per 1,000) than in the rest of the country (16 per 1,000). Poor women were far more likely to experience abortion complications, and less likely to receive treatment for complications, than nonpoor women. About 31% of pregnancies were unintended, and 24% of unintended pregnancies (8% of all pregnancies) ended in abortion. CONCLUSIONS Unsafe abortion exacts a heavy toll on women in Senegal. Reducing the barriers to effective contraceptive use and ensuring access to postabortion care without the risk of legal consequences may reduce the incidence of and complications from unsafe abortion. PMID:25856233

Estimates of the incidence of induced abortion and consequences of unsafe abortion in Senegal.

Science.gov (United States)

Sedgh, Gilda; Sylla, Amadou Hassane; Philbin, Jesse; Keogh, Sarah; Ndiaye, Salif

2015-03-01

Abortion is highly restricted by law in Senegal. Although women seek care for abortion complications, no national estimate of abortion incidence exists. Data on postabortion care and abortion in Senegal were collected in 2013 using surveys of a nationally representative sample of 168 health facilities that provide postabortion care and of 110 professionals knowledgeable about abortion service provision. Indirect estimation techniques were applied to the data to estimate the incidence of induced abortion in the country. Abortion rates and ratios were calculated for the nation and separately for the Dakar region and the rest of the country. The distribution of pregnancies by planning status and by outcome was estimated. In 2012, an estimated 51,500 induced abortions were performed in Senegal, and 16,700 (32%) resulted in complications that were treated at health facilities. The estimated abortion rate was 17 per 1,000 women aged 15-44 and the abortion ratio was 10 per 100 live births. The rate was higher in Dakar (21 per 1,000) than in the rest of the country (16 per 1,000). Poor women were far more likely to experience abortion complications, and less likely to receive treatment for complications, than nonpoor women. About 31% of pregnancies were unintended, and 24% of unintended pregnancies (8% of all pregnancies) ended in abortion. Unsafe abortion exacts a heavy toll on women in Senegal. Reducing the barriers to effective contraceptive use and ensuring access to postabortion care without the risk of legal consequences may reduce the incidence of and complications from unsafe abortion.

Framing a 'social problem': Emotion in anti-abortion activists' depiction of the abortion debate.

Science.gov (United States)

Ntontis, Evangelos; Hopkins, Nick

2018-02-27

Social psychological research on activism typically focuses on individuals' social identifications. We complement such research through exploring how activists frame an issue as a social problem. Specifically, we explore anti-abortion activists' representation of abortion and the abortion debate's protagonists so as to recruit support for the anti-abortion cause. Using interview data obtained with UK-based anti-abortion activists (N = 15), we consider how activists characterized women having abortions, pro-abortion campaigners, and anti-abortion campaigners. In particular, we consider the varied ways in which emotion featured in the representation of these social actors. Emotion featured in different ways. Sometimes, it was depicted as constituting embodied testament to the nature of reality. Sometimes, it was depicted as blocking the rational appraisal of reality. Our analysis considers how such varied meanings of emotion shaped the characterization of abortion and the abortion debate's protagonists such that anti-abortion activists were construed as speaking for women and their interests. We discuss how our analysis of the framing of issues as social problems complements and extends social psychological analyses of activism. © 2018 The British Psychological Society.

Temperate phages TP901-1 and phi LC3, belonging to the P335 species, apparently use different pathways for DNA injection in Lactococcus lactis subsp cremoris 3107

DEFF Research Database (Denmark)

Breum, Solvej Østergaard; Neve, Horst; Heller, Knut J.

2007-01-01

Five mutants of Lactococcus lactis subsp. cremoris 3107 resistant to phage TP901-1 were obtained after treatment with ethyl methanesulfonate. Two of the mutants were also resistant to phage phi LC3. The remaining three mutants were as sensitive as 3107. Mutants E46 and E100 did not adsorb the two...... phages. Mutants E119, E121 and E126 adsorbed phage phi LC3 as well as 3107 but phage TP901-1 with significantly reduced efficiency. All, except E46, could be lysogenized with phage TP901-BC1034, a derivative of TP901-1 harboring an erythromycin-resistance marker. However, the lysogenization frequency......-1. As such impairment was not seen when infecting E119, E121 and E126 with phi LC3, we conclude that TP901-1 and phi LC3 either are differently triggered by their receptor or utilize different pathways of injection....

Lysis to Kill: Evaluation of the Lytic Abilities, and Genomics of Nine Bacteriophages Infective for Gordonia spp. and Their Potential Use in Activated Sludge Foam Biocontrol.

Directory of Open Access Journals (Sweden)

Zoe A Dyson

Full Text Available Nine bacteriophages (phages infective for members of the genus Gordonia were isolated from wastewater and other natural water environments using standard enrichment techniques. The majority were broad host range phages targeting more than one Gordonia species. When their genomes were sequenced, they all emerged as double stranded DNA Siphoviridae phages, ranging from 17,562 to 103,424 bp in size, and containing between 27 and 127 genes, many of which were detailed for the first time. Many of these phage genomes diverged from the expected modular genome architecture of other characterized Siphoviridae phages and contained unusual lysis gene arrangements. Whole genome sequencing also revealed that infection with lytic phages does not appear to prevent spontaneous prophage induction in Gordonia malaquae lysogen strain BEN700. TEM sample preparation techniques were developed to view both attachment and replication stages of phage infection.

Abortion among Adolescents.

Science.gov (United States)

Adler, Nancy E.; Ozer, Emily J.; Tschann, Jeanne

2003-01-01

Reviews the current status of abortion laws pertaining to adolescents worldwide, examining questions raised by parental consent laws in the United States and by the relevant psychological research (risk of harm from abortion, informed consent, consequences of parental involvement in the abortion decision, and current debate). Discusses issues…

Complete Genome Sequence of the Novel Bacteriophage pSco-10 Infecting Staphylococcus cohnii.

Science.gov (United States)

Jun, Jin Woo; Giri, Sib Sankar; Kim, Hyoun Joong; Chi, Cheng; Yun, Saekil; Kim, Sang Guen; Kim, Sang Wha; Kang, Jeong Woo; Park, Se Chang

2017-11-22

Herein, we report the complete genome sequence of the Staphylococcus Myoviridae phage pSco-10 infecting Staphylococcus cohnii The phage pSco-10 was isolated from duck feces collected from four farms in South Korea. The current report provides valuable information for genomic study of phages. Copyright © 2017 Jun et al.

Phage-mediated Shiga toxin (Stx) horizontal gene transfer and expression in non-Shiga toxigenic Enterobacter and Escherichia coli strains.

Science.gov (United States)

Khalil, Rowaida K S; Skinner, Craig; Patfield, Stephanie; He, Xiaohua

2016-07-01

Enterobacter cloacae M12X01451 strain recently identified from a clinical specimen produces a new Stx1 subtype (Stx1e) that was not neutralized by existing anti-Stx1 monoclonal antibodies. Acquisition of stx by Ent. cloacae is rare and origin/stability of stx1e in M12X01451 is not known. In this study, we confirmed the ability of Stx1a- and Stx1e-converting phages from an Escherichia coli O157:H7 strain RM8530 and M12X01451 respectively to infect several E. coli and Ent. cloacae strains. stx1e was detected in 97.5% and 72.5% of progenies of strains lysogenized by stx1e phage after 10 (T10) and 20 (T20) subcultures, versus 65% and 17.5% for stx1a gene. Infection of M12X01451 and RM8530 with each other's phages generated double lysogens containing both phages. stx1a was lost after T10, whereas the stx1e was maintained even after T20 in M12X01451 lysogens. In RM8530 lysogens, the acquired stx1e was retained with no mutations, but 20% of stx1a was lost after T20 ELISA and western blot analyses demonstrated that Stx1e was produced in all strains lysogenized by stx1e phage; however, Stx1a was not detected in any lysogenized strain. The study results highlight the potential risks of emerging Stx-producing strains via bacteriophages either in the human gastrointestinal tract or in food production environments, which are matters of great concern and may have serious impacts on human health. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

No. 360-Induced Abortion: Surgical Abortion and Second Trimester Medical Methods.

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Costescu, Dustin; Guilbert, Édith

2018-06-01

This guideline reviews evidence relating to the provision of surgical induced abortion (IA) and second trimester medical abortion, including pre- and post-procedural care. Gynaecologists, family physicians, nurses, midwives, residents, and other health care providers who currently or intend to provide and/or teach IAs. Women with an unintended or abnormal first or second trimester pregnancy. PubMed, Medline, and the Cochrane Database were searched using the key words: first-trimester surgical abortion, second-trimester surgical abortion, second-trimester medical abortion, dilation and evacuation, induction abortion, feticide, cervical preparation, cervical dilation, abortion complications. Results were restricted to English or French systematic reviews, randomized controlled trials, clinical trials, and observational studies published from 1979 to July 2017. National and international clinical practice guidelines were consulted for review. Grey literature was not searched. The quality of evidence in this document was rated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology framework. The summary of findings is available upon request. IA is safe and effective. The benefits of IA outweigh the potential harms or costs. No new direct harms or costs identified with these guidelines. Copyright © 2018 Society of Obstetricians and Gynaecologists of Canada. All rights reserved.

[Inventory building of phages against extensively drug-resistant Acinetobacter baumannii isolated from wounds of patients with severe burn and related characteristic analysis].

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Yang, Z C; Deng, L Y; Gong, Y L; Yin, S P; Jiang, B; Huang, G T; Peng, Y Z; Hu, F Q

2016-09-20

To build inventory of phages against extensively drug-resistant Acinetobacter Baumannii isolated from wounds of inpatients of burn ICU and analyze related characteristics. In 2014 and 2015, 131 strains of extensively drug-resistant Acinetobacter Baumannii were isolated from wounds of inpatients of burn ICU from one hospital in Chongqing. In 2015, 98 strains of extensively drug-resistant Acinetobacter Baumannii were isolated from wounds of inpatients of burn ICU from 6 hospitals in Guangdong province. Above-mentioned 229 strains were collected for conducting experiments as follows: (1) Multilocus sequence typing (MLST) of strains isolated from Chongqing and Guangdong province was analyzed. (2) Sewage co-culture method was applied for isolation of phages with above-mentioned strains and sewage from Chongqing and Guangdong province. Numbers of isolated phages and times of successful isolation and unsuccessful isolation were recorded. (3) The most prevalent subtypes of strains from Chongqing and Guangdong province in 2015 were collected, and their phages respectively underwent cross infection with all strains from Chongqing and those from Guangdong province. The lysis ability of phage was observed when phage underwent cross infection with the same subtype of strain or not the same, and the lytic ratio was calculated. (4) Fluid of phage in one type was randomly selected and equally divided into 3 parts, and its titer was determined by double dilution method. Then each part of phage fluid was subdivided into 3 small parts, which were cultured with LB fluid medium and respectively stored under the condition of -20 ℃, 4 ℃, and room temperature. After being stored for 1 month and 2 months, the titer of phage was determined for evaluating stability of phage. Data were processed with Fisher's exact test, chi-square test, and one-way analysis of variance. (1) The major type of strains from Chongqing in 2014 was ST368 (45%, 31/69), and major types of strains from Chongqing

Induced abortion in Taiwan.

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Wang, P D; Lin, R S

1995-04-01

Induced abortion is widely practised in Taiwan; however, it had been illegal until 1985. It was of interest to investigate induced abortion practices in Taiwan after its legalization in 1985 in order to calculate the prevalence rate and ratio of induced abortion to live births and to pregnancies in Taiwan. A study using questionnaires through personal interviews was conducted on more than seventeen thousand women who attended a family planning service in Taipei metropolitan areas between 1991 and 1992. The reproductive history and sexual behaviour of the subjects were especially focused on during the interviews. Preliminary findings showed that 46% of the women had a history of having had an induced abortion. Among them, 54.8% had had one abortion, 29.7% had had two, and 15.5% had had three or more. The abortion ratio was 379 induced abortions per 1,000 live births and 255 per 1,000 pregnancies. The abortion ratio was highest for women younger than 20 years of age, for aboriginal women and for nulliparous women. When logistic regression was used to control for confounding variables, we found that the number of previous live births is the strongest predictor relating to women seeking induced abortion. In addition, a significant positive association exists between increasing number of induced abortions and cervical dysplasia.

Abortion Stigma Among Low-Income Women Obtaining Abortions in Western Pennsylvania: A Qualitative Assessment.

Science.gov (United States)

Gelman, Amanda; Rosenfeld, Elian A; Nikolajski, Cara; Freedman, Lori R; Steinberg, Julia R; Borrero, Sonya

2017-03-01

Abortion stigma may cause psychological distress in women who are considering having an abortion or have had one. This phenomenon has been relatively underexplored in low-income women, who may already be at an increased risk for poor abortion-related outcomes because of difficulties accessing timely and safe abortion services. A qualitative study conducted between 2010 and 2013 used semistructured interviews to explore pregnancy intentions among low-income women recruited from six reproductive health clinics in Western Pennsylvania. Transcripts from interviews with 19 participants who were planning to terminate a pregnancy or had had an abortion in the last two weeks were examined through content analysis to identify the range of attitudes they encountered that could contribute to or reflect abortion stigma, the sources of these attitudes and women's responses to them. Women commonly reported that partners, family members and they themselves held antiabortion attitudes. Such attitudes communicated that abortion is morally reprehensible, a rejection of motherhood, rare and thus potentially deviant, detrimental to future fertility and an irresponsible choice. Women reacted to external and internal negative attitudes by distinguishing themselves from other women who obtain abortions, experiencing negative emotions, and concealing or delaying their abortions. Women's reactions to antiabortion attitudes may perpetuate abortion stigma. Further research is needed to inform interventions to address abortion stigma and improve women's abortion experiences. Copyright © 2016 by the Guttmacher Institute.