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Microbial Ecology Jan 2018Honeybees are prone to parasite and pathogen infestations/infections due to their social colony life. Bacterial pathogens in particular lead to destructive infections of... (Review)
Review
Honeybees are prone to parasite and pathogen infestations/infections due to their social colony life. Bacterial pathogens in particular lead to destructive infections of the brood. European foulbrood is caused by the bacterium Melissococcus plutonius in combination with several other Gram-positive bacteria (Achromobacter eurydice, Bacillus pumilus, Brevibacillus laterosporus, Enterococcus faecalis, Paenibacillus alvei, Paenibacillus dendritiformis) involved as secondary invaders following the initial infection. More than a century ago, A. eurydice was discovered to be associated with European foulbrood and morphologically and biochemically characterized. However, since the 1950s-1960s, only a few studies are known covering the biological relevance of this bacterium. Here, we review the biology, ecology, morphology, and biochemistry and discuss the still unclear systematic classification of A. eurydice.
Topics: Achromobacter; Animals; Bees; Europe; Larva
PubMed: 28634639
DOI: 10.1007/s00248-017-1007-x -
Viruses Oct 2020Bacteriophages (phages), viruses that infect bacteria, are considered to be highly host-specific. To add to the knowledge about the evolution and development of...
Bacteriophages (phages), viruses that infect bacteria, are considered to be highly host-specific. To add to the knowledge about the evolution and development of bacteriophage speciation toward its host, we conducted a 21-day experiment with the broad host-range bacteriophage phage P14. We incubated the phage, which was previously isolated and enriched with the Alphaproteobacteria H14, with the Betaproteobacteria H5. During the experiment, we observed an increase in the phage's predation efficacy towards H5. Furthermore, genome analysis and the comparison of the bacteriophage's whole genome indicated that rather than being scattered evenly along the genome, mutations occur in specific regions. In total, 67% of the mutations with a frequency higher than 30% were located in genes that encode tail proteins, which are essential for host recognition and attachment. As control, we incubated the phage with the Alphaproteobacteria H8. In both experiments, most of the mutations appeared in the gene encoding the tail fiber protein. However, mutations in the gene encoding the tail tubular protein B were only observed when the phage was incubated with H5. This highlights the phage's tail as a key player in its adaptation to different hosts. We conclude that mutations in the phage's genome were mainly located in tail-related regions. Further investigation is needed to fully characterize the adaptation mechanisms of the phage P14.
Topics: Adaptation, Biological; Alcaligenaceae; Amino Acid Sequence; Bacteriophages; Evolution, Molecular; Genetic Variation; Genome, Viral; Host Specificity; Mutation; Phyllobacteriaceae; Viral Tail Proteins
PubMed: 33036277
DOI: 10.3390/v12101132 -
BMC Microbiology Jun 2016Achromobacter xylosoxidans is increasingly being recognized as an emerging pathogen in cystic fibrosis. Recent severe infections with A. xylosoxidans in some of our... (Review)
Review
BACKGROUND
Achromobacter xylosoxidans is increasingly being recognized as an emerging pathogen in cystic fibrosis. Recent severe infections with A. xylosoxidans in some of our cystic fibrosis (CF) patients led to a re-evaluation of the epidemiology of CF-associated A. xylosoxidans infections in two Belgian reference centres (Antwerp and Ghent). Several of these patients also stayed at the Rehabilitation Centre De Haan (RHC). In total, 59 A. xylosoxidans isolates from 31 patients (including 26 CF patients), collected between 2001 and 2014, were studied. We evaluated Matrix Assisted Laser Desorption Ionisation -Time of Flight mass spectrometry (MALDI-TOF) as an alternative for McRAPD typing.
RESULTS
Both typing approaches established the presence of a major cluster, comprising isolates, all from 21 CF patients, including from two patients sampled when staying at the RHC a decade ago. This major cluster was the same as the cluster established already a decade ago at the RHC. A minor cluster consisted of 13 isolates from miscellaneous origin. A further seven isolates, including one from a non-CF patient who had stayed recently at the RHC, were singletons.
CONCLUSIONS
Typing results of both methods were similar, indicating transmission of a single clone of A. xylosoxidans among several CF patients from at least two reference centres. Isolates of the same clone were already observed at the RHC, a decade ago. It is difficult to establish to what extent the RHC is the source of transmission, because the epidemic strain was already present when the first epidemiological study in the RHC was carried out. This study also documents the applicability of MALDI-TOF for typing of strains within the species A. xylosoxidans and the need to use the dynamic cutoff algorithm of the BioNumerics® software for correct clustering of the fingerprints.
Topics: Achromobacter denitrificans; Bacterial Typing Techniques; Belgium; Cystic Fibrosis; Gram-Negative Bacterial Infections; Humans
PubMed: 27342812
DOI: 10.1186/s12866-016-0736-1 -
Current Microbiology Sep 2022Pertussis also known as whooping cough is a respiratory infection in humans particularly with severe symptoms in infants and usually caused by Bordetella pertussis....
Pertussis also known as whooping cough is a respiratory infection in humans particularly with severe symptoms in infants and usually caused by Bordetella pertussis. However, Bordetella parapertussis can also cause a similar clinical syndrome. During 2012 to 2015, from nasal swabs sent from different provinces to the pertussis reference laboratory of Pasture Institute of Iran for pertussis confirmation, seven B. parapertussis isolates were identified by bacterial culture, biochemical tests, and the presence of IS1001 insertion in the genome. The expression of pertactin (Prn) as one the major virulence factor for bacterial adhesion was investigated using western blot. Moreover, the genomic characteristic of one recently collected isolate, IRBP134, from a seven-month infant was investigated using Illumina NextSeq sequencing protocol. The results revealed the genome with G+C content 65% and genome size 4.7 Mbp. A total of 81 single nucleotide polymorphisms and 13 short insertions and deletions were found in the genome compared to the B. parapertussis 12822 as a reference genome showing ongoing evolutionary changes. A phylogeny relationship of IRBP134 was also investigated using global B. parapertussis available genomes.
Topics: Bordetella parapertussis; Bordetella pertussis; Humans; Infant; Iran; Virulence Factors; Whooping Cough
PubMed: 36088519
DOI: 10.1007/s00284-022-03009-x -
Expert Review of Molecular Diagnostics Sep 2020Pertussis is a highly contagious respiratory infection caused by and to minor extent . Despite high vaccination coverage, epidemics persist worldwide. Laboratory... (Review)
Review
INTRODUCTION
Pertussis is a highly contagious respiratory infection caused by and to minor extent . Despite high vaccination coverage, epidemics persist worldwide. Laboratory testing with the capacity to support increasing demand and generate fast and accurate results is needed to promptly provide treatment to mitigate symptoms, prevent transmission, and thus impact infection control and disease surveillance.
AREAS COVERED
This review will describe the features of the Simplexa™ Bordetella Direct Assay and compare this technology with other existing assays. Unmet needs and future directions will be discussed.
EXPERT COMMENTARY
Resurgence of pertussis highlights the importance of reliable and accurate diagnosis. The Simplexa™ Bordetella Direct Assay provides an easy workflow, reduced hand-on time, less risk of contamination, and rapid turnaround time. The use of efficient molecular assays in routine clinical laboratory is valuable for increasing demand, improvement of infection control, and surveillance.
Topics: Bacterial Typing Techniques; Bordetella parapertussis; Bordetella pertussis; Diagnostic Tests, Routine; Humans; Nasopharynx; Whooping Cough
PubMed: 32885709
DOI: 10.1080/14737159.2020.1819240 -
Applied and Environmental Microbiology Nov 2021In this study, comprehensive analyses were performed to determine the function of an atypical MarR homolog in sp. strain As-55. Genomic analyses of sp. As-55 showed...
In this study, comprehensive analyses were performed to determine the function of an atypical MarR homolog in sp. strain As-55. Genomic analyses of sp. As-55 showed that this is located adjacent to an gene. ArsV is a flavin-dependent monooxygenase that confers resistance to the antibiotic methylarsenite [MAs(III)], the organoarsenic compound roxarsone(III) [Rox(III)], and the inorganic antimonite [Sb(III)]. Similar genes are widely distributed in arsenic-resistant bacteria. Phylogenetic analyses showed that these MarRs are found in operons predicted to be involved in resistance to inorganic and organic arsenic species, so the subfamily was named MarR. MarR orthologs have three conserved cysteine residues, which are Cys36, Cys37, and Cys157 in sp. As-55, mutation of which compromises the response to MAs(III)/Sb(III). GFP-fluorescent biosensor assays show that AdMarR (MarR protein of Achromobacter deleyi As-55) responds to trivalent As(III) and Sb(III) but not to pentavalent As(V) or Sb(V). The results of RT-qPCR assays show that is expressed constitutively in a deletion mutant, indicating that represses transcription of . Moreover, electrophoretic mobility shift assays (EMSAs) demonstrate that AdMarR binds to the promoters of both and in the absence of ligands and that DNA binding is relieved upon binding of As(III) and Sb(III). Our results demonstrate that AdMarR is a novel As(III)/Sb(III)-responsive transcriptional repressor that controls expression of which confers resistance to MAs(III), Rox(III), and Sb(III). AdMarR and its orthologs form a subfamily of MarR proteins that regulate genes conferring resistance to arsenic-containing antibiotics. In this study, a MarR family member, AdMarR was shown to regulate the gene, which confers resistance to arsenic-containing antibiotics. It is a founding member of a distinct subfamily that we refer to as MarR, regulating genes conferring resistance to arsenic and antimony antibiotic compounds. AdMarR was shown to be a repressor containing conserved cysteine residues that are required to bind As(III) and Sb(III), leading to a conformational change and subsequent derepression. Here we show that members of the MarR family are involved in regulating arsenic-containing compounds.
Topics: Achromobacter; Anti-Bacterial Agents; Arsenic; Arsenicals; Cysteine; Drug Resistance, Bacterial; Genes, Bacterial; Multigene Family; Phylogeny; Roxarsone
PubMed: 34613763
DOI: 10.1128/AEM.01588-21 -
Revista Da Sociedade Brasileira de... Jul 2023
Topics: Humans; Achromobacter denitrificans; Ecthyma; Bacteremia; Gram-Negative Bacterial Infections
PubMed: 37493732
DOI: 10.1590/0037-8682-0071-2023 -
Biotechnology Progress 2023A mathematical model is proposed for Bordetella pertussis with the main goal to better understand and describe the relation between cell growth, oxidative stress and...
A mathematical model is proposed for Bordetella pertussis with the main goal to better understand and describe the relation between cell growth, oxidative stress and NADPH levels under different oxidative conditions. The model is validated with flask experiments conducted under different conditions of oxidative stress induced by high initial glutamate concentrations, low initial inoculum and secondary culturing following exposure to starvation. The model exhibited good accuracy when calibrated and validated for the different experimental conditions. From comparisons of model predictions to data with different model mechanisms, it was concluded that intracellular reactive oxidative species only have an indirect effect on growth rate by reacting with NADPH and thereby reducing the amount of NADPH that is available for growth.
Topics: Bordetella pertussis; Fermentation; Glutamic Acid; Kinetics; Models, Biological; NADP; Oxidative Stress; Reactive Oxygen Species; Reproducibility of Results
PubMed: 36799126
DOI: 10.1002/btpr.3335 -
ELife Nov 2022Co-infected hosts, individuals that carry more than one infectious agent at any one time, have been suggested to facilitate pathogen transmission, including the...
Co-infected hosts, individuals that carry more than one infectious agent at any one time, have been suggested to facilitate pathogen transmission, including the emergence of supershedding events. However, how the host immune response mediates the interactions between co-infecting pathogens and how these affect the dynamics of shedding remains largely unclear. We used laboratory experiments and a modeling approach to examine temporal changes in the shedding of the respiratory bacterium in rabbits with one or two gastrointestinal helminth species. Experimental data showed that rabbits co-infected with one or both helminths shed significantly more , by direct contact with an agar petri dish, than rabbits with bacteria alone. Co-infected hosts generated supershedding events of higher intensity and more frequently than hosts with no helminths. To explain this variation in shedding an infection-immune model was developed and fitted to rabbits of each group. Simulations suggested that differences in the magnitude and duration of shedding could be explained by the effect of the two helminths on the relative contribution of neutrophils and specific IgA and IgG to neutralization in the respiratory tract. However, the interactions between infection and immune response at the scale of analysis that we used could not capture the rapid variation in the intensity of shedding of every rabbit. We suggest that fast and local changes at the level of respiratory tissue probably played a more important role. This study indicates that co-infected hosts are important source of variation in shedding, and provides a quantitative explanation into the role of helminths to the dynamics of respiratory bacterial infections.
Topics: Animals; Rabbits; Bordetella bronchiseptica; Bordetella Infections; Helminths; Respiratory Tract Infections; Respiratory System
PubMed: 36346138
DOI: 10.7554/eLife.70347 -
Preparative Biochemistry & Biotechnology Oct 2023This study reported physicochemical properties of purified endo-1,4-β-mannanase from the wild type, sp. and its most promising chemical mutant. The crude enzymes from...
This study reported physicochemical properties of purified endo-1,4-β-mannanase from the wild type, sp. and its most promising chemical mutant. The crude enzymes from fermentation of wild and mutant bacteria were purified by ammonium sulfate precipitation, ion exchange and gel-filtration chromatography followed by an investigation of the physicochemical properties of purified wild and mutant enzymes. β-mannanase from wild and mutant sp. exhibited 1.75 and 1.6 purification-folds with percentage recoveries of 2.6 and 2.5% and molecular weights of 61.6 and 80 kDa respectively. The wild and mutant β-mannanase were most active at 40 and 50 °C with optimum pH 6.0 for both and were thermostable with very high percentage activity but the wild-type β-mannanase showed better stability over a broad pH activity. The β-mannanase activity from the parent strain was stimulated in the presence of Mn, Co, Zn, Mg and Na. and for the wild type and its mutant were found to be 0.747 U//mL/min and 5.2 × 10mg/mL, and 0.247 U/mL/min and 2.47 × 10mg/mL, respectively. Changes that occurred in the nucleotide sequences of the most improved mutant may be attributed to its thermo-stability, thermo-tolerant and high substrate affinity- desired properties for improved bioprocesses.
Topics: beta-Mannosidase; Mutagens; Alcaligenes; Hydrogen-Ion Concentration; Enzyme Stability
PubMed: 36752611
DOI: 10.1080/10826068.2023.2172038