scholarly journals Bacteriophage PBC1 and Its Endolysin as an Antimicrobial Agent against Bacillus cereus

2015 ◽  
Vol 81 (7) ◽  
pp. 2274-2283 ◽  
Author(s):  
Minsuk Kong ◽  
Sangryeol Ryu
Keyword(s):  
Bacillus Cereus ◽  
Host Range ◽  
Catalytic Domain ◽  
Food Poisoning ◽  
Genome Comparison ◽  
Lytic Enzymes ◽  
Content Type ◽  
Virulent Phage ◽  
Narrow Host Range ◽  
Bacillus Clarkii

ABSTRACTBacillus cereusis an opportunistic human pathogen responsible for food poisoning and other, nongastrointestinal infections. Due to the emergence of multidrug-resistantB. cereusstrains, the demand for alternative therapeutic options is increasing. To address these problems, we isolated and characterized aSiphoviridaevirulent phage, PBC1, and its lytic enzymes. PBC1 showed a very narrow host range, infecting only 1 of 22B. cereusstrains. Phylogenetic analysis based on the major capsid protein revealed that PBC1 is more closely related to theBacillus clarkiiphage BCJA1c and phages of lactic acid bacteria than to the phages infectingB. cereus. Whole-genome comparison showed that the late-gene region, including the terminase gene, structural genes, and holin gene of PBC1, is similar to that fromB. cereustemperate phage 250, whereas their endolysins are different. Compared to the extreme host specificity of PBC1, its endolysin, LysPBC1, showed a much broader lytic spectrum, albeit limited to the genusBacillus. The catalytic domain of LysPBC1 when expressed alone also showedBacillus-specific lytic activity, which was lower against theB. cereusgroup but higher against theBacillus subtilisgroup than the full-length protein. Taken together, these results suggest that the virulent phage PBC1 is a useful component of a phage cocktail to controlB. cereus, even with its exceptionally narrow host range, as it can kill a strain ofB. cereusthat is not killed by other phages, and that LysPBC1 is an alternative biocontrol agent againstB. cereus.

scholarly journals The CasKR Two-Component System Is Required for the Growth of Mesophilic and Psychrotolerant Bacillus cereus Strains at Low Temperatures

2014 ◽  
Vol 80 (8) ◽  
pp. 2493-2503 ◽  
Author(s):  
Sara Esther Diomandé ◽  
Stéphanie Chamot ◽  
Vera Antolinos ◽  
Florian Vasai ◽  
Marie-Hélène Guinebretière ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Two Component System ◽  
Diverse Range ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Temperature Ranges ◽  
Different Strains

ABSTRACTThe different strains ofBacillus cereuscan grow at temperatures covering a very diverse range. SomeB. cereusstrains can grow in chilled food and consequently cause food poisoning. We have identified a new sensor/regulator mechanism involved in low-temperatureB. cereusgrowth. Construction of a mutant of this two-component system enabled us to show that this system, called CasKR, is required for growth at the minimal temperature (Tmin). CasKR was also involved in optimal cold growth aboveTminand in cell survival belowTmin. Microscopic observation showed that CasKR plays a key role in cell shape during cold growth. Introducing thecasKRgenes in a ΔcasKRmutant restored its ability to grow atTmin. Although it was first identified in the ATCC 14579 model strain, this mechanism has been conserved in most strains of theB. cereusgroup. We show that the role of CasKR in cold growth is similar in otherB. cereus sensu latostrains with different growth temperature ranges, including psychrotolerant strains.

scholarly journals Bacillus cereus NVH 0500/00 Can Adhere to Mucin but Cannot Produce Enterotoxins during Gastrointestinal Simulation

2015 ◽  
Vol 82 (1) ◽  
pp. 289-296 ◽  
Author(s):  
Varvara Tsilia ◽  
Frederiek-Maarten Kerckhof ◽  
Andreja Rajkovic ◽  
Marc Heyndrickx ◽  
Tom Van de Wiele
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Intestinal Bacteria ◽  
Low Ph ◽  
Final Concentration ◽  
Adhesion Assay ◽  
Content Type ◽  
The Stability ◽  
Bacterial Concentrations

ABSTRACTAdhesion to the intestinal epithelium could constitute an essential mechanism ofBacillus cereuspathogenesis. However, the enterocytes are protected by mucus, a secretion composed mainly of mucin glycoproteins. These may serve as nutrients and sites of adhesion for intestinal bacteria. In this study, the food poisoning bacteriumB. cereusNVH 0500/00 was exposedin vitroto gastrointestinal hurdles prior to evaluation of its attachment to mucin microcosms and its ability to produce nonhemolytic enterotoxin (Nhe). The persistence of mucin-adherentB. cereusafter simulated gut emptying was determined using a mucin adhesion assay. The stability of Nhe toward bile and pancreatin (intestinal components) in the presence of mucin agar was also investigated.B. cereuscould grow and simultaneously adhere to mucin duringin vitroileal incubation, despite the adverse effect of prior exposure to a low pH or intestinal components. The final concentration ofB. cereusin the simulated lumen at 8 h of incubation was 6.62 ± 0.87 log CFU ml−1. At that point, the percentage of adhesion was approximately 6%. No enterotoxin was detected in the ileum, due to either insufficient bacterial concentrations or Nhe degradation. Nevertheless, mucin appears to retainB. cereusand to supply it to the small intestine after simulated gut emptying. Additionally, mucin may play a role in the protection of enterotoxins from degradation by intestinal components.

scholarly journals Identification of Bacteriophages for Biocontrol of the Kiwifruit Canker Phytopathogen Pseudomonas syringae pv. actinidiae

2014 ◽  
Vol 80 (7) ◽  
pp. 2216-2228 ◽  
Author(s):  
Rebekah A. Frampton ◽  
Corinda Taylor ◽  
Angela V. Holguín Moreno ◽  
Sandra B. Visnovsky ◽  
Nicola K. Petty ◽  
...  
Keyword(s):  
Host Range ◽  
Pseudomonas Syringae ◽  
Management Strategies ◽  
Pulse Field ◽  
Resistant Bacteria ◽  
Bacterial Canker ◽  
Content Type ◽  
Narrow Host Range ◽  
Pulse Field Gel Electrophoresis ◽  
Isolation And Characterization

ABSTRACTPseudomonas syringaepv. actinidiae is a reemerging pathogen which causes bacterial canker of kiwifruit (Actinidiasp.). Since 2008, a global outbreak ofP. syringaepv. actinidiae has occurred, and in 2010 this pathogen was detected in New Zealand. The economic impact and the development of resistance inP. syringaepv. actinidiae and other pathovars against antibiotics and copper sprays have led to a search for alternative management strategies. We isolated 275 phages, 258 of which were active againstP. syringaepv. actinidiae. Extensive host range testing onP. syringaepv. actinidiae, other pseudomonads, and bacteria isolated from kiwifruit orchards showed that most phages have a narrow host range. Twenty-four were analyzed by electron microscopy, pulse-field gel electrophoresis, and restriction digestion. Their suitability for biocontrol was tested by assessing stability and the absence of lysogeny and transduction. A detailed host range was performed, phage-resistant bacteria were isolated, and resistance to other phages was examined. The phages belonged to theCaudoviralesand were analyzed based on morphology and genome size, which showed them to be representatives ofMyoviridae,Podoviridae, andSiphoviridae. Twenty-oneMyoviridaemembers have similar morphologies and genome sizes yet differ in restriction patterns, host range, and resistance, indicating a closely related group. Nine of theseMyoviridaemembers were sequenced, and each was unique. The most closely related sequenced phages were a group infectingPseudomonas aeruginosaand characterized by phages JG004 and PAK_P1. In summary, this study reports the isolation and characterization ofP. syringaepv. actinidiae phages and provides a framework for the intelligent formulation of phage biocontrol agents against kiwifruit bacterial canker.

scholarly journals Narrow-Host-Range Bacteriophages That Infect Rhizobium etli Associate with Distinct Genomic Types

2013 ◽  
Vol 80 (2) ◽  
pp. 446-454 ◽  
Author(s):  
Rosa Isela Santamaría ◽  
Patricia Bustos ◽  
Omar Sepúlveda-Robles ◽  
Luis Lozano ◽  
César Rodríguez ◽  
...  
Keyword(s):  
Host Range ◽  
Restriction Enzymes ◽  
Open Reading Frames ◽  
Rhizobium Etli ◽  
Content Type ◽  
Narrow Host Range ◽  
Bean Plants ◽  
Synthesis And Processing ◽  
A Minor

ABSTRACTIn this work, we isolated and characterized 14 bacteriophages that infectRhizobium etli. They were obtained from rhizosphere soil of bean plants from agricultural lands in Mexico using an enrichment method. The host range of these phages was narrow but variable within a collection of 48R. etlistrains. We obtained the complete genome sequence of nine phages. Four phages were resistant to several restriction enzymes andin vivocloning, probably due to nucleotide modifications. The genome size of the sequenced phages varied from 43 kb to 115 kb, with a median size of ∼45 to 50 kb. A large proportion of open reading frames of these phage genomes (65 to 70%) consisted of hypothetical and orphan genes. The remainder encoded proteins needed for phage morphogenesis and DNA synthesis and processing, among other functions, and a minor percentage represented genes of bacterial origin. We classified these phages into four genomic types on the basis of their genomic similarity, gene content, and host range. Since there are no reports of similar sequences, we propose that these bacteriophages correspond to novel species.

scholarly journals Evidence of an American Origin for Symbiosis-Related Genes in Rhizobium lusitanum

2011 ◽  
Vol 77 (16) ◽  
pp. 5665-5670 ◽  
Author(s):  
Angel Valverde ◽  
Encarna Velázquez ◽  
Emilio Cervantes ◽  
José M. Igual ◽  
Peter van Berkum
Keyword(s):  
Host Range ◽  
Leucaena Leucocephala ◽  
Sequence Data ◽  
Rapd Analysis ◽  
The Other ◽  
Randomly Amplified Polymorphic Dna ◽  
Nitrogen Fixing ◽  
Chromosomal Dna ◽  
Content Type ◽  
Narrow Host Range

ABSTRACTRandomly amplified polymorphic DNA (RAPD) analysis was used to investigate the diversity of 179 bean isolates recovered from six field sites in the Arcos de Valdevez region of northwestern Portugal. The isolates were divided into 6 groups based on the fingerprint patterns that were obtained. Representatives for each group were selected for sequence analysis of 4 chromosomal DNA regions. Five of the groups were placed withinRhizobium lusitanum, and the other group was placed withinR. tropicitype IIA. Therefore, the collection of Portuguese bean isolates was shown to include the two speciesR. lusitanumandR. tropici. In plant tests, the strains P1-7, P1-1, P1-2, and P1-16 ofR. lusitanumnodulated and formed nitrogen-fixing symbioses both withPhaseolus vulgarisandLeucaena leucocephala. A methyltransferase-encodingnodSgene identical with theR. tropicilocus that confers wide host range was detected in the strain P1-7 as well as 24 others identified asR. lusitanum. A methyltransferase-encodingnodSgene also was detected in the remaining isolates ofR. lusitanum, but in this case the locus was that identified with the narrow-host-rangeR. etli. Representatives of isolates with thenodSofR. etliformed effective nitrogen-fixing symbioses withP. vulgarisand did not nodulateL. leucocephala. From sequence data ofnodS, theR. lusitanumgenes for symbiosis were placed within those of eitherR. tropiciorR. etli. These results would support the suggestion thatR. lusitanumwas the recipient of the genes for symbiosis with beans from bothR. tropiciandR. etli.

scholarly journals Isolation of Polyvalent Bacteriophages by Sequential Multiple-Host Approaches

2015 ◽  
Vol 82 (3) ◽  
pp. 808-815 ◽  
Author(s):  
Pingfeng Yu ◽  
Jacques Mathieu ◽  
Mengyan Li ◽  
Zhaoyi Dai ◽  
Pedro J. J. Alvarez
Keyword(s):  
Host Range ◽  
Pseudomonas Syringae ◽  
Burst Size ◽  
Broad Host Range ◽  
Ecological Significance ◽  
Content Type ◽  
Narrow Host Range ◽  
Isolation Methods ◽  
Culture Independent ◽  
K 12

ABSTRACTMany studies on phage biology are based on isolation methods that may inadvertently select for narrow-host-range phages. Consequently, broad-host-range phages, whose ecological significance is largely unexplored, are consistently overlooked. To enhance research on such polyvalent phages, we developed two sequential multihost isolation methods and tested both culture-dependent and culture-independent phage libraries for broad infectivity. Lytic phages isolated from activated sludge were capable of interspecies or even interorder infectivity without a significant reduction in the efficiency of plating (0.45 to 1.15). Two polyvalent phages (PX1 of thePodoviridaefamily and PEf1 of theSiphoviridaefamily) were characterized in terms of adsorption rate (3.54 × 10−10to 8.53 × 10−10ml/min), latent time (40 to 55 min), and burst size (45 to 99 PFU/cell), using different hosts. These phages were enriched with a nonpathogenic host (Pseudomonas putidaF1 orEscherichia coliK-12) and subsequently used to infect model problematic bacteria. By using a multiplicity of infection of 10 in bacterial challenge tests, >60% lethality was observed forPseudomonas aeruginosarelative to uninfected controls. The corresponding lethality forPseudomonas syringaewas ∼50%. Overall, this work suggests that polyvalent phages may be readily isolated from the environment by using different sequential hosts, and this approach should facilitate the study of their ecological significance as well as enable novel applications.

scholarly journals Prevalence, Genetic Diversity, and Host Range of Tectiviruses among Members of the Bacillus cereus Group

2014 ◽  
Vol 80 (14) ◽  
pp. 4138-4152 ◽  
Author(s):  
Annika Gillis ◽  
Jacques Mahillon
Keyword(s):  
Genetic Diversity ◽  
Bacillus Cereus ◽  
Host Range ◽  
Simple Relationship ◽  
Biological Processes ◽  
Bacillus Cereus Group ◽  
Variable Regions ◽  
Content Type ◽  
The Family ◽  
Group Members

ABSTRACTGIL01, Bam35, GIL16, AP50, and Wip1 are tectiviruses preying on theBacillus cereusgroup. Despite the significant contributions of phages in different biological processes, little is known about the dealings taking place between tectiviruses and their Gram-positive bacterial hosts. Therefore, this work focuses on characterizing the interactions between tectiviruses and theB. cereusgroup by assessing their occurrence and genetic diversity and evaluating their host range. To study the occurrence of tectiviruses in theB. cereusgroup, 2,000 isolates were evaluated using primers designed to be specific to two variable regions detected in previously described elements. PCR and propagation tests revealed that tectivirus-like elements occurred in less than 3% of the isolates. Regardless of this limited distribution, several novel tectiviruses were found, and partial DNA sequencing indicated that a greater diversity exists within the familyTectiviridae. Analyses of the selected variable regions, along with their host range, showed that tectiviruses in theB. cereusgroup can be clustered mainly into two different groups: the ones infectingB. anthracisand those isolated from otherB. cereusgroup members. In order to address the host range of some novel tectiviruses, 120 strains were tested for sensitivity. The results showed that all the tested tectiviruses produced lysis in at least oneB. cereus sensu latostrain. Moreover, no simple relationship between the infection patterns of the tectiviruses and their diversity was found.

scholarly journals Silage Collected from Dairy Farms Harbors an Abundance of Listeriaphages with Considerable Host Range and Genome Size Diversity

2012 ◽  
Vol 78 (24) ◽  
pp. 8666-8675 ◽  
Author(s):  
Kitiya Vongkamjan ◽  
Andrea Moreno Switt ◽  
Henk C. den Bakker ◽  
Esther D. Fortes ◽  
Martin Wiedmann
Keyword(s):  
Host Range ◽  
Dairy Farm ◽  
Dairy Farms ◽  
Genomic Diversity ◽  
Broad Host Range ◽  
Content Type ◽  
Narrow Host Range ◽  
Food Borne ◽  
Size Diversity ◽  
Range Characterization

ABSTRACTSince the food-borne pathogenListeria monocytogenesis common in dairy farm environments, it is likely that phages infecting this bacterium (“listeriaphages”) are abundant on dairy farms. To better understand the ecology and diversity of listeriaphages on dairy farms and to develop a diverse phage collection for further studies, silage samples collected on two dairy farms were screened forL. monocytogenesand listeriaphages. While only 4.5% of silage samples tested positive forL. monocytogenes, 47.8% of samples were positive for listeriaphages, containing up to >1.5 × 104PFU/g. Host range characterization of the 114 phage isolates obtained, with a reference set of 13L. monocytogenesstrains representing the nine major serotypes and four lineages, revealed considerable host range diversity; phage isolates were classified into nine lysis groups. While one serotype 3c strain was not lysed by any phage isolates, serotype 4 strains were highly susceptible to phages and were lysed by 63.2 to 88.6% of phages tested. Overall, 12.3% of phage isolates showed a narrow host range (lysing 1 to 5 strains), while 28.9% of phages represented broad host range (lysing ≥11 strains). Genome sizes of the phage isolates were estimated to range from approximately 26 to 140 kb. The extensive host range and genomic diversity of phages observed here suggest an important role of phages in the ecology ofL. monocytogeneson dairy farms. In addition, the phage collection developed here has the potential to facilitate further development of phage-based biocontrol strategies (e.g., in silage) and other phage-based tools.

scholarly journals Cooccurrence of Broad- and Narrow-Host-Range Viruses Infecting the Bloom-Forming Toxic Cyanobacterium Microcystis aeruginosa

2019 ◽  
Vol 85 (18) ◽  
Author(s):  
Daichi Morimoto ◽  
Kento Tominaga ◽  
Yosuke Nishimura ◽  
Naohiro Yoshida ◽  
Shigeko Kimura ◽  
...  
Keyword(s):  
Host Range ◽  
Microcystis Aeruginosa ◽  
Current Knowledge ◽  
Broad Host Range ◽  
Antiviral Defense ◽  
Content Type ◽  
Narrow Host Range ◽  
Toxic Cyanobacterium ◽  
Antiviral Responses ◽  
Group Ii

ABSTRACT Viruses play important roles in regulating the abundance and composition of bacterial populations in aquatic ecosystems. The bloom-forming toxic cyanobacterium Microcystis aeruginosa is predicted to interact with diverse cyanoviruses, resulting in Microcystis population diversification. However, current knowledge of the genomes from these viruses and their infection programs is limited to those of Microcystis virus Ma-LMM01. Here, we performed a time series sampling at a small pond in Japan during a Microcystis bloom and then investigated the genomic information and transcriptional dynamics of Microcystis-interacting viruses using metagenomic and metatranscriptomic approaches. We identified 15 viral genomic fragments classified into three groups, groups I (including Ma-LMM01), II (high abundance and transcriptional activity), and III (new lineages). According to the phylogenetic distribution of Microcystis strains possessing spacers against each viral group, the group II-original viruses interacted with all three phylogenetically distinct Microcystis population types (phylotypes), whereas the groups I and III-original viruses interacted with only one or two phylotypes, indicating the cooccurrence of broad- (group II) and narrow (groups I and III)-host-range viruses in the bloom. These viral fragments showed the highest transcriptional levels during daytime regardless of their genomic differences. Interestingly, M. aeruginosa expressed antiviral defense genes in the environment, unlike what was seen with an Ma-LMM01 infection in a previous culture experiment. Given that broad-host-range viruses often induce antiviral responses within alternative hosts, our findings suggest that such antiviral responses might inhibit viral multiplication, mainly that of broad-host-range viruses like those in group II. IMPORTANCE The bloom-forming toxic cyanobacterium Microcystis aeruginosa is thought to have diversified its population through the interactions between host and viruses in antiviral defense systems. However, current knowledge of viral genomes and infection programs is limited to those of Microcystis virus Ma-LMM01, which was a narrow host range in which it can escape from the highly abundant host defense systems. Our metagenomic approaches unveiled the cooccurrence of narrow- and broad-host-range Microcystis viruses, which included fifteen viral genomic fragments from Microcystis blooms that were classified into three groups. Interestingly, Microcystis antiviral defense genes were expressed against viral infection in the environment, unlike what was seen in a culture experiment with Ma-LMM01. Given that viruses with a broad host range often induce antiviral responses within alternative hosts, our findings suggest that antiviral responses inhibit viral reproduction, especially that of broad-range viruses like those in group II. This paper augments our understanding of the interactions between M. aeruginosa and its viruses and fills an important knowledge gap.

scholarly journals Survival and Germination of Bacillus cereus Spores without Outgrowth or Enterotoxin Production duringIn VitroSimulation of Gastrointestinal Transit

2012 ◽  
Vol 78 (21) ◽  
pp. 7698-7705 ◽  
Author(s):  
Siele Ceuppens ◽  
Mieke Uyttendaele ◽  
Katrien Drieskens ◽  
Marc Heyndrickx ◽  
Andreja Rajkovic ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Gastrointestinal Transit ◽  
Intestinal Bacteria ◽  
Content Type ◽  
Enterotoxin Production ◽  
Food Isolate ◽  
High Concentrations ◽  
Ph Decrease

ABSTRACTTo study the gastrointestinal survival and enterotoxin production of the food-borne pathogenBacillus cereus, anin vitrosimulation experiment was developed to mimic gastrointestinal passage in 5 phases: (i) the mouth, (ii) the stomach, with gradual pH decrease and fractional emptying, (iii) the duodenum, with high concentrations of bile and digestive enzymes, (iv) dialysis to ensure bile reabsorption, and (v) the ileum, with competing human intestinal bacteria. Four differentB. cereusstrains were cultivated and sporulated in mashed potato medium to obtain an inoculum of 7.0 log spores/ml. The spores showed survival and germination during thein vitrosimulation of gastrointestinal passage, but vegetative outgrowth of the spores was suppressed by the intestinal bacteria during the final ileum phase. No bacterial proliferation or enterotoxin production was observed, despite the high inoculum levels. Little strain variability was observed: except for the psychrotrophic food isolate, the spores of all strains survived well throughout the gastrointestinal passage. Thein vitrosimulation experiments investigated the survival and enterotoxin production ofB. cereusin the gastrointestinal lumen. The results obtained support the hypothesis that localized interaction ofB. cereuswith the host's epithelium is required for diarrheal food poisoning.

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