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Sample records for pathogenic staphylococcal species

  1. Moonlighting bacteriophage proteins derepress staphylococcal pathogenicity islands.

    PubMed

    Tormo-Más, María Angeles; Mir, Ignacio; Shrestha, Archana; Tallent, Sandra M; Campoy, Susana; Lasa, Iñigo; Barbé, Jordi; Novick, Richard P; Christie, Gail E; Penadés, José R

    2010-06-10

    Staphylococcal superantigen-carrying pathogenicity islands (SaPIs) are discrete, chromosomally integrated units of approximately 15 kilobases that are induced by helper phages to excise and replicate. SaPI DNA is then efficiently encapsidated in phage-like infectious particles, leading to extremely high frequencies of intra- as well as intergeneric transfer. In the absence of helper phage lytic growth, the island is maintained in a quiescent prophage-like state by a global repressor, Stl, which controls expression of most of the SaPI genes. Here we show that SaPI derepression is effected by a specific, non-essential phage protein that binds to Stl, disrupting the Stl-DNA complex and thereby initiating the excision-replication-packaging cycle of the island. Because SaPIs require phage proteins to be packaged, this strategy assures that SaPIs will be transferred once induced. Several different SaPIs are induced by helper phage 80alpha and, in each case, the SaPI commandeers a different non-essential phage protein for its derepression. The highly specific interactions between different SaPI repressors and helper-phage-encoded antirepressors represent a remarkable evolutionary adaptation involved in pathogenicity island mobilization.

  2. Cross-Talk between Staphylococcus aureus and Other Staphylococcal Species via the agr Quorum Sensing System

    PubMed Central

    Canovas, Jaime; Baldry, Mara; Bojer, Martin S.; Andersen, Paal S.; Grzeskowiak, Piotr K.; Stegger, Marc; Damborg, Peter; Olsen, Christian A.; Ingmer, Hanne

    2016-01-01

    Staphylococci are associated with both humans and animals. While most are non-pathogenic colonizers, Staphylococcus aureus is an opportunistic pathogen capable of causing severe infections. S. aureus virulence is controlled by the agr quorum sensing system responding to secreted auto-inducing peptides (AIPs) sensed by AgrC, a two component histidine kinase. agr loci are found also in other staphylococcal species and for Staphylococcus epidermidis, the encoded AIP represses expression of agr regulated virulence genes in S. aureus. In this study we aimed to better understand the interaction between staphylococci and S. aureus, and show that this interaction may eventually lead to the identification of new anti-virulence candidates to target S. aureus infections. Here we show that culture supernatants of 37 out of 52 staphylococcal isolates representing 17 different species inhibit S. aureus agr. The dog pathogen, Staphylococcus schleiferi, expressed the most potent inhibitory activity and was active against all four agr classes found in S. aureus. By employing a S. aureus strain encoding a constitutively active AIP receptor we show that the activity is mediated via agr. Subsequent cloning and heterologous expression of the S. schleiferi AIP in S. aureus demonstrated that this molecule was likely responsible for the inhibitory activity, and further proof was provided when pure synthetic S. schleiferi AIP was able to completely abolish agr induction of an S. aureus reporter strain. To assess impact on S. aureus virulence, we co-inoculated S. aureus and S. schleiferi in vivo in the Galleria mellonella wax moth larva, and found that expression of key S. aureus virulence factors was abrogated. Our data show that the S. aureus agr locus is highly responsive to other staphylococcal species suggesting that agr is an inter-species communication system. Based on these results we speculate that interactions between S. aureus and other colonizing staphylococci will significantly

  3. Cross-Talk between Staphylococcus aureus and Other Staphylococcal Species via the agr Quorum Sensing System.

    PubMed

    Canovas, Jaime; Baldry, Mara; Bojer, Martin S; Andersen, Paal S; Grzeskowiak, Piotr K; Stegger, Marc; Damborg, Peter; Olsen, Christian A; Ingmer, Hanne

    2016-01-01

    Staphylococci are associated with both humans and animals. While most are non-pathogenic colonizers, Staphylococcus aureus is an opportunistic pathogen capable of causing severe infections. S. aureus virulence is controlled by the agr quorum sensing system responding to secreted auto-inducing peptides (AIPs) sensed by AgrC, a two component histidine kinase. agr loci are found also in other staphylococcal species and for Staphylococcus epidermidis, the encoded AIP represses expression of agr regulated virulence genes in S. aureus. In this study we aimed to better understand the interaction between staphylococci and S. aureus, and show that this interaction may eventually lead to the identification of new anti-virulence candidates to target S. aureus infections. Here we show that culture supernatants of 37 out of 52 staphylococcal isolates representing 17 different species inhibit S. aureus agr. The dog pathogen, Staphylococcus schleiferi, expressed the most potent inhibitory activity and was active against all four agr classes found in S. aureus. By employing a S. aureus strain encoding a constitutively active AIP receptor we show that the activity is mediated via agr. Subsequent cloning and heterologous expression of the S. schleiferi AIP in S. aureus demonstrated that this molecule was likely responsible for the inhibitory activity, and further proof was provided when pure synthetic S. schleiferi AIP was able to completely abolish agr induction of an S. aureus reporter strain. To assess impact on S. aureus virulence, we co-inoculated S. aureus and S. schleiferi in vivo in the Galleria mellonella wax moth larva, and found that expression of key S. aureus virulence factors was abrogated. Our data show that the S. aureus agr locus is highly responsive to other staphylococcal species suggesting that agr is an inter-species communication system. Based on these results we speculate that interactions between S. aureus and other colonizing staphylococci will significantly

  4. Genetic engineering of untransformable coagulase-negative staphylococcal pathogens.

    PubMed

    Winstel, Volker; Kühner, Petra; Rohde, Holger; Peschel, Andreas

    2016-05-01

    Coagulase-negative staphylococci (CoNS) are recognized as significant opportunistic pathogens. However, current knowledge of virulence mechanisms is very limited because a significant proportion of CoNS are refractory to available techniques for DNA transformation. We describe an efficient protocol for plasmid transfer using bacteriophage Φ187, which can transduce plasmid DNA to a wide range of CoNS from a unique, engineered Staphylococcus aureus strain. The use of a restriction-deficient, modification-proficient S. aureus PS187 mutant, which has a CoNS-type bacteriophage surface receptor, allows plasmid transfer to CoNS even when they are refractory to electroporation. Once the Φ187 titer reaches 10(9) plaque-forming units per milliliter, plasmid transfer can be accomplished within 1-2 d. Thus, our protocol is a major technical advance offering attractive opportunities for research on CoNS-mediated infections.

  5. [The significance of some potentially pathogenic microorganisms in occurrence of food toxicosis. Part 1. S. aureus and staphylococcal enterotoxins].

    PubMed

    Efimochkina, N R; Kuvaeva, I B; Fluer, F S

    2011-01-01

    The data on the nomenclature, classification and properties of staphylococci and staphylococcal enterotoxins produced by them are presented. The analysis of cultural and biochemical properties of 137 strains of staphylococci isolated from raw milk and "Russian" cheese was performed. The high degree of correlation between the ability of S. aureus produce enterotoxins and the presence of enzymes coagulase, thermostable DNase, and other factors of pathogenicity is established.

  6. Staphylococcal pathogenicity island interference with helper phage reproduction is a paradigm of molecular parasitism.

    PubMed

    Ram, Geeta; Chen, John; Kumar, Krishan; Ross, Hope F; Ubeda, Carles; Damle, Priyadarshan K; Lane, Kristin D; Penadés, José R; Christie, Gail E; Novick, Richard P

    2012-10-02

    Staphylococcal pathogenicity islands (SaPIs) carry superantigen and resistance genes and are extremely widespread in Staphylococcus aureus and in other Gram-positive bacteria. SaPIs represent a major source of intrageneric horizontal gene transfer and a stealth conduit for intergeneric gene transfer; they are phage satellites that exploit the life cycle of their temperate helper phages with elegant precision to enable their rapid replication and promiscuous spread. SaPIs also interfere with helper phage reproduction, blocking plaque formation, sharply reducing burst size and enhancing the survival of host cells following phage infection. Here, we show that SaPIs use several different strategies for phage interference, presumably the result of convergent evolution. One strategy, not described previously in the bacteriophage microcosm, involves a SaPI-encoded protein that directly and specifically interferes with phage DNA packaging by blocking the phage terminase small subunit. Another strategy involves interference with phage reproduction by diversion of the vast majority of virion proteins to the formation of SaPI-specific small infectious particles. Several SaPIs use both of these strategies, and at least one uses neither but possesses a third. Our studies illuminate a key feature of the evolutionary strategy of these mobile genetic elements, in addition to their carriage of important genes-interference with helper phage reproduction, which could ensure their transferability and long-term persistence.

  7. Temporal study of staphylococcal species on healthy dogs.

    PubMed

    Cox, H U; Hoskins, J D; Newman, S S; Foil, C S; Turnwald, G H; Roy, A F

    1988-06-01

    During a 1-year period, specimens were obtained monthly from 5 hair coat and 7 mucous membrane sites of 11 healthy dogs. Among 804 isolates of staphylococci, 13 species were identified. Staphylococcus intermedius was the most frequently isolated (40.2% of total isolates) coagulase-positive species, and S xylosus was the most frequently isolated (17.3%) coagulase-negative species. Moreover, S intermedius was the most frequently isolated species from the 12 sites evaluated and was isolated persistently from 8 of the 9 dogs that completed the 1-year study. On the basis of a commercial identification system, 14 profile numbers were identified for isolates of S intermedius. However, 2 profile numbers accounted for a majority (70.9%) of the isolates. Specific S intermedius biotypes identified on the basis of hemolysis, coagulase production, beta-lactamase activity, and antimicrobial susceptibility patterns were found repeatedly in 3 dogs. Seemingly, S intermedius was a resident of the normal bacterial microflora of these dogs; however, the inability to isolate S intermedius from 1 dog during the study year indicated that not all dogs harbor S intermedius as a resident microorganism.

  8. A novel approach to eliminate detection of contaminating Staphylococcal species introduced during clinical testing

    PubMed Central

    Ao, Wanyuan; Clifford, Adrianne; Corpuz, Maylene; Jenison, Robert

    2017-01-01

    We describe here a strategy that can distinguish between Staphylococcus species truly present in a clinical sample from contaminating Staphylococcus species introduced during the testing process. Contaminating Staphylococcus species are present at low levels in PCR reagents and colonize lab personnel. To eliminate detection of contaminants, we describe an approach that utilizes addition of sufficient quantities of either non-target Staphylococcal cells (Staphylococcus succinus or Staphylococcus muscae) or synthetic oligonucleotide templates to helicase dependent isothermal amplification reactions to consume Staphylococcus-specific tuf and mecA gene primers such that contaminating Staphylococcus amplification is suppressed to below assay limits of detection. The suppressor template DNA is designed with perfect homology to the primers used in the assay but an internal sequence that is unrelated to the Staphylococcal species targeted for detection. Input amount of the suppressor is determined by a mathematical model described herein and is demonstrated to completely suppress contaminating levels of Staphylococcus while not negatively impacting the appropriate clinical assay limit of detection. We have applied this approach to improve the specificity of detection of Staphylococcus species present in positive blood cultures using a chip-based array that produces results visible to the unaided eye. PMID:28225823

  9. Identification of staphylococcal species based on variations in protein sequences (mass spectrometry) and DNA sequence (sodA microarray).

    PubMed

    Kooken, Jennifer; Fox, Karen; Fox, Alvin; Altomare, Diego; Creek, Kim; Wunschel, David; Pajares-Merino, Sara; Martínez-Ballesteros, Ilargi; Garaizar, Javier; Oyarzabal, Omar; Samadpour, Mansour

    2014-02-01

    This report is among the first using sequence variation in newly discovered protein markers for staphylococcal (or indeed any other bacterial) speciation. Variation, at the DNA sequence level, in the sodA gene (commonly used for staphylococcal speciation) provided excellent correlation. Relatedness among strains was also assessed using protein profiling using microcapillary electrophoresis and pulsed field electrophoresis. A total of 64 strains were analyzed including reference strains representing the 11 staphylococcal species most commonly isolated from man (Staphylococcus aureus and 10 coagulase negative species [CoNS]). Matrix assisted time of flight ionization/ionization mass spectrometry (MALDI TOF MS) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC ESI MS/MS) were used for peptide analysis of proteins isolated from gel bands. Comparison of experimental spectra of unknowns versus spectra of peptides derived from reference strains allowed bacterial identification after MALDI TOF MS analysis. After LC-MS/MS analysis of gel bands bacterial speciation was performed by comparing experimental spectra versus virtual spectra using the software X!Tandem. Finally LC-MS/MS was performed on whole proteomes and data analysis also employing X!tandem. Aconitate hydratase and oxoglutarate dehydrogenase served as marker proteins on focused analysis after gel separation. Alternatively on full proteomics analysis elongation factor Tu generally provided the highest confidence in staphylococcal speciation.

  10. Staphylococcus jettensis sp. nov., a coagulase-negative staphylococcal species isolated from human clinical specimens.

    PubMed

    De Bel, Annelies; Van Hoorde, Koenraad; Wybo, Ingrid; Vandoorslaer, Kristof; Echahidi, Fedoua; De Brandt, Evie; Schumann, Peter; Ieven, Margareta; Soetens, Oriane; Piérard, Denis; Vandamme, Peter

    2013-09-01

    Eight coagulase-negative, novobiocin-susceptible staphylococcal strains were isolated from human clinical specimens at two different Belgian medical facilities. All strains were non-motile, Gram-stain-positive, catalase-positive cocci. DNA G+C content, peptidoglycan type, menaquinone pattern, the presence of teichoic acid and cellular fatty acid composition were in agreement with the characteristics of species of the genus Staphylococcus. Sequencing of the 16S rRNA gene and four housekeeping genes (dnaJ, tuf, gap and rpoB) demonstrated that these strains constitute a separate taxon within the genus Staphylococcus. Less than 41% DNA-DNA hybridization with the most closely related species of the genus Staphylococcus (Staphylococcus haemolyticus, Staphylococcus hominis and Staphlococcus lugdunensis) was observed. Key biochemical characteristics that allowed these bacteria to be distinguished from their nearest phylogenetic neighbours are arginine dihydrolase positivity, ornithine decarboxylase negativity and inability to produce acid aerobically from D-mannose, α-lactose and turanose. Acid is produced aerobically from trehalose. Based on these results, a novel species of the genus Staphylococcus is described and named Staphylococcus jettensis sp. nov. The type strain is SEQ110(T) ( =LMG 26879(T) =CCUG 62657(T) =DSM 26618(T)).

  11. Inhibition of exotoxin production by mobile genetic element SCCmec-encoded psm-mec RNA is conserved in staphylococcal species.

    PubMed

    Ikuo, Mariko; Nagano, Gentaro; Saito, Yuki; Mao, Han; Sekimizu, Kazuhisa; Kaito, Chikara

    2014-01-01

    Staphylococcal species acquire antibiotic resistance by incorporating the mobile-genetic element SCCmec. We previously found that SCCmec-encoded psm-mec RNA suppresses exotoxin production as a regulatory RNA, and the psm-mec translation product increases biofilm formation in Staphylococcus aureus. Here, we examined whether the regulatory role of psm-mec on host bacterial virulence properties is conserved among other staphylococcal species, S. epidermidis and S. haemolyticus, both of which are important causes of nosocomial infections. In S. epidermidis, introduction of psm-mec decreased the production of cytolytic toxins called phenol-soluble modulins (PSMs) and increased biofilm formation. Introduction of psm-mec with a stop-codon mutation that did not express PSM-mec protein but did express psm-mec RNA also decreased PSM production, but did not increase biofilm formation. Thus, the psm-mec RNA inhibits PSM production, whereas the PSM-mec protein increases biofilm formation in S. epidermidis. In S. haemolyticus, introduction of psm-mec decreased PSM production, but did not affect biofilm formation. The mutated psm-mec with a stop-codon also caused the same effect. Thus, the psm-mec RNA also inhibits PSM production in S. haemolyticus. These findings suggest that the inhibitory role of psm-mec RNA on exotoxin production is conserved among staphylococcal species, although the stimulating effect of the psm-mec gene on biofilm formation is not conserved.

  12. Transcriptomic analysis of staphylococcal sRNAs: insights into species-specific adaption and the evolution of pathogenesis

    PubMed Central

    2016-01-01

    Next-generation sequencing technologies have dramatically increased the rate at which new genomes are sequenced. Accordingly, automated annotation programs have become adept at identifying and annotating protein coding regions, as well as common and conserved RNAs. Additionally, RNAseq techniques have advanced our ability to identify and annotate regulatory RNAs (sRNAs), which remain significantly understudied. Recently, our group catalogued and annotated all previously known and newly identified sRNAs in several Staphylococcus aureus strains. These complete annotation files now serve as tools to compare the sRNA content of S. aureus with other bacterial strains to investigate the conservation of their sRNomes. Accordingly, in this study we performed RNAseq on two staphylococcal species, Staphylococcus epidermidis and Staphylococcus carnosus, identifying 118 and 89 sRNAs in these organisms, respectively. The sRNA contents of all three species were then compared to elucidate their common and species-specific sRNA content, identifying a core set of between 53 and 36 sRNAs encoded in each organism. In addition, we determined that S. aureus has the largest set of unique sRNAs (137) while S. epidermidishas the fewest (25). Finally, we identify a highly conserved sequence and structural motif differentially represented within, yet common to, both S. aureus and S. epidermidis. Collectively, in this study, we uncover the sRNome common to three staphylococcal species, shedding light on sRNAs that are likely to be involved in basic physiological processes common to the genus. More significantly, we have identified species-specific sRNAs that are likely to influence the individual lifestyle and behaviour of these diverse staphylococcal strains. PMID:28348860

  13. Transfer of plasmid DNA to clinical coagulase-negative staphylococcal pathogens by using a unique bacteriophage.

    PubMed

    Winstel, Volker; Kühner, Petra; Krismer, Bernhard; Peschel, Andreas; Rohde, Holger

    2015-04-01

    Genetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a unique Staphylococcus aureus strain via a specific S. aureus bacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinical Staphylococcus epidermidis isolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion.

  14. Meningitis - staphylococcal

    MedlinePlus

    ... causes meningitis. Causes Staphylococcal meningitis is caused by staphylococcus bacteria. When it is caused by Staphylococcus aureus or Staphylococcus epidermidis bacteria, it usually develops ...

  15. Staphylococcal pathogenicity island DNA packaging system involving cos-site packaging and phage-encoded HNH endonucleases

    PubMed Central

    Quiles-Puchalt, Nuria; Carpena, Nuria; Alonso, Juan C.; Novick, Richard P.; Marina, Alberto; Penadés, José R.

    2014-01-01

    Staphylococcal pathogenicity islands (SaPIs) are the prototypical members of a widespread family of chromosomally located mobile genetic elements that contribute substantially to intra- and interspecies gene transfer, host adaptation, and virulence. The key feature of their mobility is the induction of SaPI excision and replication by certain helper phages and their efficient encapsidation into phage-like infectious particles. Most SaPIs use the headful packaging mechanism and encode small terminase subunit (TerS) homologs that recognize the SaPI-specific pac site and determine SaPI packaging specificity. Several of the known SaPIs do not encode a recognizable TerS homolog but are nevertheless packaged efficiently by helper phages and transferred at high frequencies. In this report, we have characterized one of the non–terS-coding SaPIs, SaPIbov5, and found that it uses two different, undescribed packaging strategies. SaPIbov5 is packaged in full-sized phage-like particles either by typical pac-type helper phages, or by cos-type phages—i.e., it has both pac and cos sites—a configuration that has not hitherto been described for any mobile element, phages included—and uses the two different phage-coded TerSs. To our knowledge, this is the first example of SaPI packaging by a cos phage, and in this, it resembles the P4 plasmid of Escherichia coli. Cos-site packaging in Staphylococcus aureus is additionally unique in that it requires the HNH nuclease, carried only by cos phages, in addition to the large terminase subunit, for cos-site cleavage and melting. PMID:24711396

  16. Staphylococcal acid phosphatase binds to endothelial cells via charge interaction; a pathogenic role in Wegener’s granulomatosis?

    PubMed Central

    Brons, R H; Bakker, H I; Van Wijk, R T; Van Dijk, N W; Muller Kobold, A C; Limburg, P C; Manson, W L; Kallenberg, C G M; Cohen Tervaert, J W

    2000-01-01

    The majority of patients with Wegener’s granulomatosis (WG) are chronic nasal carriers of Staphylococcus aureus. Chronic nasal carriage of S. aureus is associated with an increased risk of developing a relapse of the disease. The mechanism by which this occurs is still unknown. We hypothesized that a cationic protein of S. aureus, staphylococcal acid phosphatase (SAcP), acts as a planted antigen and initiates glomerulonephritis and vasculitis in patients with WG. In order to test the hypothesis that SAcP can act as a planted antigen in WG, we studied the ability of SAcP to bind to human umbilical vein endothelial cells (HUVEC) and human glomerular endothelial cells. We also studied whether this binding can be prevented by preincubation with an anionic protein, and whether binding of SAcP activates endothelial cells. We also evaluated whether antibodies in sera of patients with WG are able to bind to endothelial cell-bound SAcP. The results show that SAcP can act as a planted antigen by binding to both types of endothelial cells in a concentration-dependent manner. Binding of concentrations as low as 4 μ g/ml can be detected on HUVEC within 5 min of incubation. Binding of SAcP to endothelial cells was charge-dependent but did not activate endothelial cells. Finally, endothelial cell-bound SAcP was recognized by sera of patients with WG. The data suggest a possible pathogenic role for SAcP by acting as a planted antigen thereby initiating glomerulonephritis and vasculitis in patients with WG. PMID:10691932

  17. Staphylococcal pathogenicity island DNA packaging system involving cos-site packaging and phage-encoded HNH endonucleases.

    PubMed

    Quiles-Puchalt, Nuria; Carpena, Nuria; Alonso, Juan C; Novick, Richard P; Marina, Alberto; Penadés, José R

    2014-04-22

    Staphylococcal pathogenicity islands (SaPIs) are the prototypical members of a widespread family of chromosomally located mobile genetic elements that contribute substantially to intra- and interspecies gene transfer, host adaptation, and virulence. The key feature of their mobility is the induction of SaPI excision and replication by certain helper phages and their efficient encapsidation into phage-like infectious particles. Most SaPIs use the headful packaging mechanism and encode small terminase subunit (TerS) homologs that recognize the SaPI-specific pac site and determine SaPI packaging specificity. Several of the known SaPIs do not encode a recognizable TerS homolog but are nevertheless packaged efficiently by helper phages and transferred at high frequencies. In this report, we have characterized one of the non-terS-coding SaPIs, SaPIbov5, and found that it uses two different, undescribed packaging strategies. SaPIbov5 is packaged in full-sized phage-like particles either by typical pac-type helper phages, or by cos-type phages--i.e., it has both pac and cos sites--a configuration that has not hitherto been described for any mobile element, phages included--and uses the two different phage-coded TerSs. To our knowledge, this is the first example of SaPI packaging by a cos phage, and in this, it resembles the P4 plasmid of Escherichia coli. Cos-site packaging in Staphylococcus aureus is additionally unique in that it requires the HNH nuclease, carried only by cos phages, in addition to the large terminase subunit, for cos-site cleavage and melting.

  18. Phenol-soluble modulins – critical determinants of staphylococcal virulence

    PubMed Central

    Cheung, Gordon Y. C.; Joo, Hwang-Soo; Chatterjee, Som S.; Otto, Michael

    2014-01-01

    Phenol-soluble modulins (PSMs) are a recently discovered family of amphipathic, alpha-helical peptides that have multiple roles in staphylococcal pathogenesis and contribute to a large extent to the pathogenic success of virulent staphylococci, such as Staphylococcus aureus. PSMs may cause lysis of many human cell types including leukocytes and erythrocytes, stimulate inflammatory responses, and contribute to biofilm development. PSMs appear to have an original role in the commensal lifestyle of staphylococci, where they facilitate growth and spreading on epithelial surfaces. Aggressive, cytolytic PSMs seem to have evolved from that original role and are mainly expressed in highly virulent S. aureus. Here we will review the biochemistry, genetics and role of PSMs in the commensal and pathogenic lifestyles of staphylococci, discuss how diversification of PSMs defines the aggressiveness of staphylococcal species, and evaluate potential avenues to target PSMs for drug development against staphylococcal infections. PMID:24372362

  19. Genomics of Pathogenic Vibrio Species

    NASA Astrophysics Data System (ADS)

    Dziejman, Michelle; Yildiz, Fitnat H.

    Members of the heterotrophic bacterial family Vibrionaceae are native inhabitants of aquatic environments worldwide, constituting a diverse and abundant component of marine microbial organisms. Over 60 species of the genus Vibrio have been identified (Thompson et al., 2004) and their phenotypic heterogeneity is well documented. The ecology of the genus remains less well understood, however, despite reports that vibrios are the dominant microorganisms inhabiting the superficial water layer and colonizing the chitinous exoskeleton of zooplankton (e.g., copepods, Thompson et al., 2004). Although some species were originally isolated from seawater as free living organisms, most were isolated in association with marine life such as bivalves, fish, eels, or shrimp.

  20. Staphylococcal Infections

    MedlinePlus

    ... Page Content Article Body Infections caused by staphylococcal organisms can lead to a variety of diseases, including ... blood tests may be ordered to identify the organism involved. Antibiotics taken by mouth are usually prescribed ...

  1. Reprint of "Identification of staphylococcal species based on variations in protein sequences (mass spectrometry) and DNA sequence (sodA microarray)".

    PubMed

    Kooken, Jennifer; Fox, Karen; Fox, Alvin; Altomare, Diego; Creek, Kim; Wunschel, David; Pajares-Merino, Sara; Martínez-Ballesteros, Ilargi; Garaizar, Javier; Oyarzabal, Omar; Samadpour, Mansour

    2014-01-01

    This report is among the first using sequence variation in newly discovered protein markers for staphylococcal (or indeed any other bacterial) speciation. Variation, at the DNA sequence level, in the sodA gene (commonly used for staphylococcal speciation) provided excellent correlation. Relatedness among strains was also assessed using protein profiling using microcapillary electrophoresis and pulsed field electrophoresis. A total of 64 strains were analyzed including reference strains representing the 11 staphylococcal species most commonly isolated from man (Staphylococcus aureus and 10 coagulase negative species [CoNS]). Matrix assisted time of flight ionization/ionization mass spectrometry (MALDI TOF MS) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC ESI MS/MS) were used for peptide analysis of proteins isolated from gel bands. Comparison of experimental spectra of unknowns versus spectra of peptides derived from reference strains allowed bacterial identification after MALDI TOF MS analysis. After LC-MS/MS analysis of gel bands bacterial speciation was performed by comparing experimental spectra versus virtual spectra using the software X!Tandem. Finally LC-MS/MS was performed on whole proteomes and data analysis also employing X!tandem. Aconitate hydratase and oxoglutarate dehydrogenase served as marker proteins on focused analysis after gel separation. Alternatively on full proteomics analysis elongation factor Tu generally provided the highest confidence in staphylococcal speciation.

  2. Staphylococcal carriage in man

    PubMed Central

    Munch-Petersen, E.

    1961-01-01

    The author reviews the published findings on the carriage of Staphylococcus pyogenes var. aureus during the last two decades, dealing mainly with observations made in British Commonwealth countries, Scandinavia and the USA. The importance of the role played by staphylococcal carriers in the spread of infection both in hospitals and among adults and children in the general population is clearly brought out and is of particular interest in view of the current increase in resistance of staphylococcal strains to antibiotics. There does not appear to have been any well-defined trend towards either an increase or a decrease in staphylococcal carriage in the past twenty years; annual variations have been quite considerable and the precipitate drop in the carriage rate in hospitals in 1949 (perhaps due to the extensive use of penicillin) has since been made up. A particularly high carriage rate was found among hospital staff and twice as high a rate among children born in hospitals as among those delivered at home. Closer study and better control of staphylococcal infections in hospital wards are clearly necessary. It is appreciated, however, that, before more effective control measures can be taken, there must be improvements in the present methods of sampling, in the testing of strains for pathogenicity and in other techniques. PMID:13726780

  3. Comparative Phylogenomics of Pathogenic and Nonpathogenic Species

    PubMed Central

    Whiston, Emily; Taylor, John W.

    2015-01-01

    The Ascomycete Onygenales order embraces a diverse group of mammalian pathogens, including the yeast-forming dimorphic fungal pathogens Histoplasma capsulatum, Paracoccidioides spp. and Blastomyces dermatitidis, the dermatophytes Microsporum spp. and Trichopyton spp., the spherule-forming dimorphic fungal pathogens in the genus Coccidioides, and many nonpathogens. Although genomes for all of the aforementioned pathogenic species are available, only one nonpathogen had been sequenced. Here, we enhance comparative phylogenomics in Onygenales by adding genomes for Amauroascus mutatus, Amauroascus niger, Byssoonygena ceratinophila, and Chrysosporium queenslandicum—four nonpathogenic Onygenales species, all of which are more closely related to Coccidioides spp. than any other known Onygenales species. Phylogenomic detection of gene family expansion and contraction can provide clues to fungal function but is sensitive to taxon sampling. By adding additional nonpathogens, we show that LysM domain-containing proteins, previously thought to be expanding in some Onygenales, are contracting in the Coccidioides-Uncinocarpus clade, as are the self-nonself recognition Het loci. The denser genome sampling presented here highlights nearly 800 genes unique to Coccidiodes, which have significantly fewer known protein domains and show increased expression in the endosporulating spherule, the parasitic phase unique to Coccidioides spp. These genomes provide insight to gene family expansion/contraction and patterns of individual gene gain/loss in this diverse order—both major drivers of evolutionary change. Our results suggest that gene family expansion/contraction can lead to adaptive radiations that create taxonomic orders, while individual gene gain/loss likely plays a more significant role in branch-specific phenotypic changes that lead to adaptation for species or genera. PMID:26613950

  4. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... consisting of a bacterial virus intended for medical purposes to identify pathogenic staphylococcal bacteria through use of the bacteria's susceptibility to destruction by the virus. Test results are...

  5. Molecular Diagnosis of Pathogenic Sporothrix Species

    PubMed Central

    Rodrigues, Anderson Messias; de Hoog, G. Sybren; de Camargo, Zoilo Pires

    2015-01-01

    Background Sporotrichosis is a chronic (sub)cutaneous infection caused by thermodimorphic fungi in the order, Ophiostomatales. These fungi are characterized by major differences in routes of transmission, host predilections, species virulence, and susceptibilities to antifungals. Sporothrix species emerge in the form of outbreaks. Large zoonoses and sapronoses are ongoing in Brazil and China, respectively. Current diagnostic methods based on morphology and physiology are inaccurate due to closely related phenotypes with overlapping components between pathogenic and non-pathogenic Sporothrix. There is a critical need for new diagnostic tools that are specific, sensitive, and cost-effective. Methodology We developed a panel of novel markers, based on calmodulin (CAL) gene sequences, for the large-scale diagnosis and epidemiology of clinically relevant members of the Sporothrix genus, and its relative, Ophiostoma. We identified specific PCR-based markers for S. brasiliensis, S. schenckii, S. globosa, S. mexicana, S. pallida, and O. stenoceras. We employed a murine model of disseminated sporotrichosis to optimize a PCR assay for detecting Sporothrix in clinical specimens. Results Primer-BLAST searches revealed candidate sequences that were conserved within a single species. Species-specific primers showed no significant homology with human, mouse, or microorganisms outside the Sporothrix genus. The detection limit was 10–100 fg of DNA in a single round of PCR for identifying S. brasiliensis, S. schenckii, S. globosa, S. mexicana, and S. pallida. A simple, direct PCR assay, with conidia as a source of DNA, was effective for rapid, low-cost genotyping. Samples from a murine model of disseminated sporotrichosis confirmed the feasibility of detecting S. brasiliensis and S. schenckii DNA in spleen, liver, lungs, heart, brain, kidney, tail, and feces of infected animals. Conclusions This PCR-based method could successfully detect and identify a single species in samples

  6. Staphylococcus argensis sp. nov., a novel staphylococcal species isolated from an aquatic environment.

    PubMed

    Heß, Stefanie; Gallert, Claudia

    2015-08-01

    A staphylocoagulase-negative, novobiocin-susceptible strain (M4S-6T) of a species of the genus Staphylococcus was isolated from the river Argen in Southern Germany. It was assigned to the genus Staphylococcus due to the presence of the fatty acids, ai-C15 : 0, i-C15 : 0, i-C17 : 0, ai-C17 : 0, and of menaquinone (MK-7) in the cytoplasmic membrane, which are typical of coagulase-negative staphylococci. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, an unknown phospholipid and an unknown glycolipid. Although the 16S gene sequence of strain M4S-6T revealed a 98% similarity with its closest relative, Staphylococcus pettenkoferi, it could be distinguished by several phenotypical and physiological markers. In contrast to S. pettenkoferi, M4S-6T was ornithine decarboxylase-positive, urease-negative and could use formiate and l-histidine as carbon-sources; nitrate was not reduced. Whereas S. pettenkoferi could grow with d(-)-mannitol, d-sorbitol, gluconic acid, l-proline, carboxymethylcellulose and lignosulfonate, M4S-6T was not able to grow with these substances. The results of 16S rRNA gene sequence analysis and of phenotypic testing indicated that M4S-6T was a representative of a novel species for which the name Staphylococcus argensis sp. nov., is proposed with the type strain M4S-6T (DSM 29875T = CIP 110904T).

  7. Emergence and accumulation of novel pathogens suppress an invasive species.

    PubMed

    Stricker, Kerry Bohl; Harmon, Philip F; Goss, Erica M; Clay, Keith; Luke Flory, S

    2016-04-01

    Emerging pathogens are a growing threat to human health, agriculture and the diversity of ecological communities but may also help control problematic species. Here we investigated the diversity, distribution and consequences of emerging fungal pathogens infecting an aggressive invasive grass that is rapidly colonising habitats throughout the eastern USA. We document the recent emergence and accumulation over time of diverse pathogens that are members of a single fungal genus and represent multiple, recently described or undescribed species. We also show that experimental suppression of these pathogens increased host performance in the field, demonstrating the negative effects of emerging pathogens on invasive plants. Our results suggest that invasive species can facilitate pathogen emergence and amplification, raising concerns about movement of pathogens among agricultural, horticultural, and wild grasses. However, one possible benefit of pathogen accumulation is suppression of aggressive invaders over the long term, potentially abating their negative impacts on native communities.

  8. Ring Infiltrate in Staphylococcal Keratitis

    PubMed Central

    Wallang, Batriti S.; Sharma, Savitri; Sahu, Srikant K.; Mittal, Ruchi

    2013-01-01

    Smear and culture tests of corneal scrapings from a patient with a ring infiltrate confirmed significant growth of a Staphylococcus species resistant to fluoroquinolones. Because of nonresponse to medical management, the patient underwent therapeutic penetrating keratoplasty. Staphylococcal infection of the cornea may appear as a ring-like infiltrate that is recalcitrant to medical management. PMID:23100354

  9. Usefulness of Multiplex Real-Time PCR for Simultaneous Pathogen Detection and Resistance Profiling of Staphylococcal Bacteremia

    PubMed Central

    Chung, Yousun; Kim, Taek Soo; Min, Young Gi; Hong, Yun Ji; Park, Jeong Su; Hwang, Sang Mee; Song, Kyoung-Ho; Kim, Eu Suk; Kim, Hong Bin; Song, Junghan; Kim, Eui-Chong

    2016-01-01

    Staphylococci are the leading cause of nosocomial blood stream infections. Fast and accurate identification of staphylococci and confirmation of their methicillin resistance are crucial for immediate treatment with effective antibiotics. A multiplex real-time PCR assay that targets mecA, femA specific for S. aureus, femA specific for S. epidermidis, 16S rRNA for universal bacteria, and 16S rRNA specific for staphylococci was developed and evaluated with 290 clinical blood culture samples containing Gram-positive cocci in clusters (GPCC). For the 262 blood cultures identified to the species level with the MicroScan WalkAway system (Siemens Healthcare Diagnostics, USA), the direct real-time PCR assay of positive blood cultures showed very good agreement for the categorization of staphylococci into methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. epidermidis (MRSE), methicillin-susceptible S. epidermidis (MSSE), methicillin-resistant non-S. epidermidis CoNS (MRCoNS), and methicillin-susceptible non-S. epidermidis CoNS (MSCoNS) (κ = 0.9313). The direct multiplex real-time PCR assay of positive blood cultures containing GPCC can provide essential information at the critical point of infection with a turnaround time of no more than 4 h. Further studies should evaluate the clinical outcome of using this rapid real-time PCR assay in glycopeptide antibiotic therapy in clinical settings. PMID:27403436

  10. Phytotoxins produced by plant pathogenic Streptomyces species.

    PubMed

    Bignell, D R D; Fyans, J K; Cheng, Z

    2014-02-01

    Streptomyces is a large genus consisting of soil-dwelling, filamentous bacteria that are best known for their capability of producing a vast array of medically and agriculturally useful secondary metabolites. In addition, a small number of Streptomyces spp. are capable of colonizing and infecting the underground portions of living plants and causing economically important crop diseases such as potato common scab (CS). Research into the mechanisms of Streptomyces plant pathogenicity has led to the identification and characterization of several phytotoxic secondary metabolites that are known or suspected of contributing to diseases in various plants. The best characterized are the thaxtomin phytotoxins, which play a critical role in the development of CS, acid scab and soil rot of sweet potato. In addition, the best-characterized CS-causing pathogen, Streptomyces scabies, produces a molecule that is predicted to resemble the Pseudomonas syringae coronatine phytotoxin and which contributes to seedling disease symptom development. Other Streptomyces phytotoxic secondary metabolites that have been identified include concanamycins, FD-891 and borrelidin. Furthermore, there is evidence that additional, unknown metabolites may participate in Streptomyces plant pathogenicity. Such revelations have implications for the rational development of better management procedures for controlling CS and other Streptomyces plant diseases.

  11. A large, mobile pathogenicity island confers plant pathogenicity on Streptomyces species.

    PubMed

    Kers, Johan A; Cameron, Kimberly D; Joshi, Madhumita V; Bukhalid, Raghida A; Morello, Joanne E; Wach, Michael J; Gibson, Donna M; Loria, Rosemary

    2005-02-01

    Potato scab is a globally important disease caused by polyphyletic plant pathogenic Streptomyces species. Streptomyces acidiscabies, Streptomyces scabies and Streptomyces turgidiscabies possess a conserved biosynthetic pathway for the nitrated dipeptide phytotoxin thaxtomin. These pathogens also possess the nec1 gene which encodes a necrogenic protein that is an independent virulence factor. In this article we describe a large (325-660 kb) pathogenicity island (PAI) conserved among these three plant pathogenic Streptomyces species. A partial DNA sequence of this PAI revealed the thaxtomin biosynthetic pathway, nec1, a putative tomatinase gene, and many mobile genetic elements. In addition, the PAI from S. turgidiscabies contains a plant fasciation (fas) operon homologous to and colinear with the fas operon in the plant pathogen Rhodococcus fascians. The PAI was mobilized during mating from S. turgidiscabies to the non-pathogens Streptomyces coelicolor and Streptomyces diastatochromogenes on a 660 kb DNA element and integrated site-specifically into a putative integral membrane lipid kinase. Acquisition of the PAI conferred a pathogenic phenotype on S. diastatochromogenes but not on S. coelicolor. This PAI is the first to be described in a Gram-positive plant pathogenic bacterium and is responsible for the emergence of new plant pathogenic Streptomyces species in agricultural systems.

  12. Development of a microarray for identification of pathogenic Clostridium species

    PubMed Central

    Janvilisri, Tavan; Scaria, Joy; Gleed, Robin; Fubini, Susan; Bonkosky, Michelle M.; Gröhn, Yrjö T.; Chang, Yung-Fu

    2009-01-01

    In recent years, Clostridium species have rapidly reemerged as human and animal pathogens. The detection and identification of pathogenic Clostridium species is therefore critical for clinical diagnosis and antimicrobial therapy. Traditional diagnostic techniques for clostridia are laborious, time-consuming and may adversely affect the therapeutic outcome. In this study, we developed an oligonucleotide diagnostic microarray for pathogenic Clostridium species. The microarray specificity was tested against 65 Clostridium isolates. The applicability of this microarray in a clinical setting was assessed with the use of mock stool samples. The microarray was successful in discriminating at least four species with the limit of detection as low as 104 CFU/ml. In addition, the pattern of virulence and antibiotic resistance genes of tested strains were determined through the microarrays. This approach demonstrates the high-throughput detection and identification of Clostridium species and provides advantages over traditional methods. Microarray-based techniques are promising applications for clinical diagnosis and epidemiological investigations. PMID:19879710

  13. Two Phages, phiIPLA-RODI and phiIPLA-C1C, Lyse Mono- and Dual-Species Staphylococcal Biofilms

    PubMed Central

    Gutiérrez, Diana; Vandenheuvel, Dieter; Martínez, Beatriz; Rodríguez, Ana; Lavigne, Rob

    2015-01-01

    Phage therapy is a promising option for fighting against staphylococcal infections. Two lytic phages, vB_SauM_phiIPLA-RODI (phiIPLA-RODI) and vB_SepM_phiIPLA-C1C (phiIPLA-C1C), belonging to the Myoviridae family and exhibiting wide host ranges, were characterized in this study. The complete genome sequences comprised 142,348 bp and 140,961 bp and contained 213 and 203 open reading frames, respectively. The gene organization was typical of Spounavirinae members, with long direct terminal repeats (LTRs), genes grouped into modules not clearly separated from each other, and several group I introns. In addition, four genes encoding tRNAs were identified in phiIPLA-RODI. Comparative DNA sequence analysis showed high similarities with two phages, GH15 and 676Z, belonging to the Twort-like virus genus (nucleotide identities of >84%); for phiIPLA-C1C, a high similarity with phage phiIBB-SEP1 was observed (identity of 80%). Challenge assays of phages phiIPLA-RODI and phiIPLA-C1C against planktonic staphylococcal cells confirmed their lytic ability, as they were able to remove 5 log units in 8 h. Exposure of biofilms to phages phiIPLA-RODI and phiIPLA-C1C reduced the amount of adhered bacteria to about 2 log units in both monospecies and dual-species biofilms, but phiIPLA-RODI turned out to be as effective as the mixture of both phages. Moreover, the frequencies of bacteriophage-insensitive mutants (BIMs) of Staphylococcus aureus and S. epidermidis with resistance to phiIPLA-RODI and phiIPLA-C1C were low, at 4.05 × 10−7 ± 2.34 × 10−9 and 1.1 × 10−7 ± 2.08 × 10−9, respectively. Overall, a generally reduced fitness in the absence of phages was observed for BIMs, which showed a restored phage-sensitive phenotype in a few generations. These results confirm that lytic bacteriophages can be efficient biofilm-disrupting agents, supporting their potential as antimicrobials against staphylococcal infections. PMID:25746992

  14. Genetic islands in pome fruit pathogenic and non-pathogenic Erwinia species and related plasmids

    PubMed Central

    Llop, Pablo

    2015-01-01

    New pathogenic bacteria belonging to the genus Erwinia associated with pome fruit trees (Erwinia, E. piriflorinigrans, E. uzenensis) have been increasingly described in the last years, and comparative analyses have found that all these species share several genetic characteristics. Studies at different level (whole genome comparison, virulence genes, plasmid content, etc.) show a high intraspecies homogeneity (i.e., among E. amylovora strains) and also abundant similarities appear between the different Erwinia species: presence of plasmids of similar size in the pathogenic species; high similarity in several genes associated with exopolysaccharide production and hence, with virulence, as well as in some other genes, in the chromosomes. Many genetic similarities have been observed also among some of the plasmids (and genomes) from the pathogenic species and E. tasmaniensis or E. billingiae, two epiphytic species on the same hosts. The amount of genetic material shared in this genus varies from individual genes to clusters, genomic islands and genetic material that even may constitute a whole plasmid. Recent research on evolution of erwinias point out the horizontal transfer acquisition of some genomic islands that were subsequently lost in some species and several pathogenic traits that are still present. How this common material has been obtained and is efficiently maintained in different species belonging to the same genus sharing a common ecological niche provides an idea of the origin and evolution of the pathogenic Erwinia and the interaction with non-pathogenic species present in the same niche, and the role of the genes that are conserved in all of them. PMID:26379649

  15. Genetic islands in pome fruit pathogenic and non-pathogenic Erwinia species and related plasmids.

    PubMed

    Llop, Pablo

    2015-01-01

    New pathogenic bacteria belonging to the genus Erwinia associated with pome fruit trees (Erwinia, E. piriflorinigrans, E. uzenensis) have been increasingly described in the last years, and comparative analyses have found that all these species share several genetic characteristics. Studies at different level (whole genome comparison, virulence genes, plasmid content, etc.) show a high intraspecies homogeneity (i.e., among E. amylovora strains) and also abundant similarities appear between the different Erwinia species: presence of plasmids of similar size in the pathogenic species; high similarity in several genes associated with exopolysaccharide production and hence, with virulence, as well as in some other genes, in the chromosomes. Many genetic similarities have been observed also among some of the plasmids (and genomes) from the pathogenic species and E. tasmaniensis or E. billingiae, two epiphytic species on the same hosts. The amount of genetic material shared in this genus varies from individual genes to clusters, genomic islands and genetic material that even may constitute a whole plasmid. Recent research on evolution of erwinias point out the horizontal transfer acquisition of some genomic islands that were subsequently lost in some species and several pathogenic traits that are still present. How this common material has been obtained and is efficiently maintained in different species belonging to the same genus sharing a common ecological niche provides an idea of the origin and evolution of the pathogenic Erwinia and the interaction with non-pathogenic species present in the same niche, and the role of the genes that are conserved in all of them.

  16. A New Family of Secreted Toxins in Pathogenic Neisseria Species

    PubMed Central

    Jamet, Anne; Jousset, Agnès B.; Euphrasie, Daniel; Mukorako, Paulette; Boucharlat, Alix; Ducousso, Alexia; Charbit, Alain; Nassif, Xavier

    2015-01-01

    The genus Neisseria includes both commensal and pathogenic species which are genetically closely related. However, only meningococcus and gonococcus are important human pathogens. Very few toxins are known to be secreted by pathogenic Neisseria species. Recently, toxins secreted via type V secretion system and belonging to the widespread family of contact-dependent inhibition (CDI) toxins have been described in numerous species including meningococcus. In this study, we analyzed loci containing the maf genes in N. meningitidis and N. gonorrhoeae and proposed a novel uniform nomenclature for maf genomic islands (MGIs). We demonstrated that mafB genes encode secreted polymorphic toxins and that genes immediately downstream of mafB encode a specific immunity protein (MafI). We focused on a MafB toxin found in meningococcal strain NEM8013 and characterized its EndoU ribonuclease activity. maf genes represent 2% of the genome of pathogenic Neisseria, and are virtually absent from non-pathogenic species, thus arguing for an important biological role. Indeed, we showed that overexpression of one of the four MafB toxins of strain NEM8013 provides an advantage in competition assays, suggesting a role of maf loci in niche adaptation. PMID:25569427

  17. Distribution of Plasmids in Distinct Leptospira Pathogenic Species

    PubMed Central

    Wang, Yanzhuo; Zhuang, Xuran; Zhong, Yi; Zhang, Cuicai; Zhang, Yan; Zeng, Lingbing; Zhu, Yongzhang; He, Ping; Dong, Ke; Pal, Utpal; Guo, Xiaokui; Qin, Jinhong

    2015-01-01

    Leptospirosis, caused by pathogenic Leptospira, is a worldwide zoonotic infection. The genus Leptospira includes at least 21 species clustered into three groups—pathogens, non-pathogens, and intermediates—based on 16S rRNA phylogeny. Research on Leptospira is difficult due to slow growth and poor transformability of the pathogens. Recent identification of extrachromosomal elements besides the two chromosomes in L. interrogans has provided new insight into genome complexity of the genus Leptospira. The large size, low copy number, and high similarity of the sequence of these extrachromosomal elements with the chromosomes present challenges in isolating and detecting them without careful genome assembly. In this study, two extrachromosomal elements were identified in L. borgpetersenii serovar Ballum strain 56604 through whole genome assembly combined with S1 nuclease digestion following pulsed-field gel electrophoresis (S1-PFGE) analysis. Further, extrachromosomal elements in additional 15 Chinese epidemic strains of Leptospira, comprising L. borgpetersenii, L. weilii, and L. interrogans, were successfully separated and identified, independent of genome sequence data. Southern blot hybridization with extrachromosomal element-specific probes, designated as lcp1, lcp2 and lcp3-rep, further confirmed their occurrences as extrachromosomal elements. In total, 24 plasmids were detected in 13 out of 15 tested strains, among which 11 can hybridize with the lcp1-rep probe and 11 with the lcp2-rep probe, whereas two can hybridize with the lcp3-rep probe. None of them are likely to be species-specific. Blastp search of the lcp1, lcp2, and lcp3-rep genes with a nonredundant protein database of Leptospira species genomes showed that their homologous sequences are widely distributed among clades of pathogens but not non-pathogens or intermediates. These results suggest that the plasmids are widely distributed in Leptospira species, and further elucidation of their biological

  18. Reactive oxygen species, essential molecules, during plant-pathogen interactions.

    PubMed

    Camejo, Daymi; Guzmán-Cedeño, Ángel; Moreno, Alexander

    2016-06-01

    Reactive oxygen species (ROS) are continually generated as a consequence of the normal metabolism in aerobic organisms. Accumulation and release of ROS into cell take place in response to a wide variety of adverse environmental conditions including salt, temperature, cold stresses and pathogen attack, among others. In plants, peroxidases class III, NADPH oxidase (NOX) locates in cell wall and plasma membrane, respectively, may be mainly enzymatic systems involving ROS generation. It is well documented that ROS play a dual role into cells, acting as important signal transduction molecules and as toxic molecules with strong oxidant power, however some aspects related to its function during plant-pathogen interactions remain unclear. This review focuses on the principal enzymatic systems involving ROS generation addressing the role of ROS as signal molecules during plant-pathogen interactions. We described how the chloroplasts, mitochondria and peroxisomes perceive the external stimuli as pathogen invasion, and trigger resistance response using ROS as signal molecule.

  19. Staphylococcal epidemiology in Antarctica.

    PubMed

    Cameron, A S

    1970-03-01

    An investigation of staphylococcal epidemiology was undertaken at an Australian National Antarctic Research Expedition station during 1965-1966. It concerned the carriage of staphylococci by the men and their dogs, and the occurrence of staphylococci in the station environment. The year-long study indicated that coagulase-negative strains survived better in the Antarctic environment than coagulase-positive strains. It was demonstrated that naturally acquired coagulase-positive strains could not maintain colonization on forearm skin under the usual cold exposure experienced at Mawson station, though coagulase-negative skin strains appeared to thrive during the winter. Staphylococcus albus and S. aureus were able to persist in the anterior nares, despite the sometimes lower temperatures recorded in this micro-climate, probably because of the greater humidity and denser populations found there. The majority of the nasal carriers of S. aureus were persistent carriers, only two men in 27 being found to be occasional carriers of nasal strains, which was consistent with the observation that transfer of this pathogen from man to man is not common under Antarctic conditions. Half of the 27 sledge dogs at the station were found to carry coagulase-positive staphylococci but this did not appear to be of pathological significance to their human handlers. The local inanimate environment, including mess hut, sleeping huts and sleeping bags used on expeditions, was searched for contamination by S. aureus but none was detected.

  20. Are Reactive Oxygen Species Always Detrimental to Pathogens?

    PubMed Central

    Bozza, Marcelo T.

    2014-01-01

    Abstract Reactive oxygen species (ROS) are deadly weapons used by phagocytes and other cell types, such as lung epithelial cells, against pathogens. ROS can kill pathogens directly by causing oxidative damage to biocompounds or indirectly by stimulating pathogen elimination by various nonoxidative mechanisms, including pattern recognition receptors signaling, autophagy, neutrophil extracellular trap formation, and T-lymphocyte responses. Thus, one should expect that the inhibition of ROS production promote infection. Increasing evidences support that in certain particular infections, antioxidants decrease and prooxidants increase pathogen burden. In this study, we review the classic infections that are controlled by ROS and the cases in which ROS appear as promoters of infection, challenging the paradigm. We discuss the possible mechanisms by which ROS could promote particular infections. These mechanisms are still not completely clear but include the metabolic effects of ROS on pathogen physiology, ROS-induced damage to the immune system, and ROS-induced activation of immune defense mechanisms that are subsequently hijacked by particular pathogens to act against more effective microbicidal mechanisms of the immune system. The effective use of antioxidants as therapeutic agents against certain infections is a realistic possibility that is beginning to be applied against viruses. Antioxid. Redox Signal. 20, 1000–1037. PMID:23992156

  1. Novel organisms: comparing invasive species, GMOs, and emerging pathogens.

    PubMed

    Jeschke, Jonathan M; Keesing, Felicia; Ostfeld, Richard S

    2013-09-01

    Invasive species, range-expanding species, genetically modified organisms (GMOs), synthetic organisms, and emerging pathogens increasingly affect the human environment. We propose a framework that allows comparison of consecutive stages that such novel organisms go through. The framework provides a common terminology for novel organisms, facilitating knowledge exchange among researchers, managers, and policy makers that work on, or have to make effective decisions about, novel organisms. The framework also indicates that knowledge about the causes and consequences of stage transitions for the better studied novel organisms, such as invasive species, can be transferred to more poorly studied ones, such as GMOs and emerging pathogens. Finally, the framework advances understanding of how climate change can affect the establishment, spread, and impacts of novel organisms, and how biodiversity affects, and is affected by, novel organisms.

  2. Comparative Pathogenicity of United Kingdom Isolates of the Emerging Pathogen Candida auris and Other Key Pathogenic Candida Species

    PubMed Central

    Szekely, Adrien; Johnson, Elizabeth M.

    2016-01-01

    ABSTRACT Candida auris, first described in 2009, has since emerged as an important, multidrug-resistant, nosocomial agent of candidemia, with large outbreaks reported worldwide and high mortality rates associated with therapeutic failure. The current study employed C. auris isolates from a variety of centers in the United Kingdom to evaluate the pathogenicity of this emerging pathogen compared to that of other common pathogenic yeast species in the invertebrate Galleria mellonella infection model. We showed that C. auris isolates differ in their growth characteristics in vitro, with a proportion of isolates failing to release daughter cells after budding, resulting in the formation of large aggregates of cells that cannot be physically disrupted. Our results also demonstrate strain-specific differences in the behavior of C. auris in G. mellonella, with the aggregate-forming isolates exhibiting significantly less pathogenicity than their nonaggregating counterparts. Importantly, the nonaggregating isolates exhibited pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus, despite the fact that C. auris isolates do not produce hyphae and produce only rudimentary pseudohyphae either in vitro or in G. mellonella. IMPORTANCE The incidence of invasive candidiasis, which includes candidemia and deep tissue infections, continues to rise and is associated with considerable mortality rates. Candida albicans remains the most common cause of invasive candidiasis, although the prevalence of non-albicans species has increased over recent years. Since its first description in 2009, Candida auris has emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide. However, despite receiving considerable attention, little is known concerning the pathogenicity of this emerging fungal pathogen. Here, using the Galleria mellonella insect systemic infection model, we show

  3. Intra- and inter-generic transfer of pathogenicity island-encoded virulence genes by cos phages.

    PubMed

    Chen, John; Carpena, Nuria; Quiles-Puchalt, Nuria; Ram, Geeta; Novick, Richard P; Penadés, José R

    2015-05-01

    Bacteriophage-mediated horizontal gene transfer is one of the primary driving forces of bacterial evolution. The pac-type phages are generally thought to facilitate most of the phage-mediated gene transfer between closely related bacteria, including that of mobile genetic elements-encoded virulence genes. In this study, we report that staphylococcal cos-type phages transferred the Staphylococcus aureus pathogenicity island SaPIbov5 to non-aureus staphylococcal species and also to different genera. Our results describe the first intra- and intergeneric transfer of a pathogenicity island by a cos phage, and highlight a gene transfer mechanism that may have important implications for pathogen evolution.

  4. Identifying and subtyping species of dangerous pathogens by automated ribotyping.

    PubMed

    Grif, Katharina; Dierich, Manfred P; Much, Peter; Hofer, Erwin; Allerberger, Franz

    2003-09-01

    An investigation of dangerous bacterial pathogens was conducted to determine the usefulness of automated rRNA operon ribotyping (RiboPrinter system) to identify species. A total of 26 isolates comprising Bacillus anthracis, Brucella spp., Burkholderia mallei, Francisella tularensis, and Yersinia pestis were tested using restriction endonucleases EcoRI, PstI, PvuII and AseI. The main problem was that the system's database-relying on EcoRI as restriction enzyme-does not contain the essential dangerous pathogens. B. anthracis was misidentified as B. cereus and Y. pestis as Y. pseudotuberculosis. Two isolates of F. tularensis ssp. holarctica were falsely identified as Vibrio cholerae. This study underscores that riboprint patterns generated with a single restriction enzyme are not always unique for each of the species tested. Using more than one enzyme, the RiboPrinter proved to be a valuable primary typing method. Databases of commercially available systems for the identification of bacteria should include the most important dangerous pathogens.

  5. Evaluation of Staf-Sistem 18-R for identification of staphylococcal clinical isolates to the species level.

    PubMed Central

    Piccolomini, R; Catamo, G; Picciani, C; D'Antonio, D

    1994-01-01

    The accuracy and efficiency of Staf-Sistem 18-R (Liofilchem s.r.l., Roseto degli Abruzzi, Teramo, Italy) were compared with those of conventional biochemical methods to identify 523 strains belonging to 16 different human Staphylococcus species. Overall, 491 strains (93.9%) were correctly identified (percentage of identification, > or = 90.0), with 28 (5.4%) requiring supplementary tests for complete identification. For 14 isolates (2.8%), the strains did not correspond to any key in the codebook and could not be identified by the manufacturer's computer service. Only 18 isolates (3.4%) were misidentified. The system is simple to use, is easy to handle, gives highly reproducible results, and is inexpensive. With the inclusion of more discriminating tests and adjustment in supplementary code numbers for some species, such as Staphylococcus lugdunensis and Staphylococcus schleiferi, Staf-Sistem 18-R is a suitable alternative for identification of human coagulase-positive and coagulase-negative Staphylococcus species in microbiological laboratories. Images PMID:8195373

  6. The Staphylococcal Biofilm: Adhesins, regulation, and host response

    PubMed Central

    Paharik, Alexandra E.; Horswill, Alexander R.

    2015-01-01

    The Staphylococci comprise a diverse genus of Gram-positive, non-motile commensal organisms that inhabit the skin and mucous membranes of humans and other mammals. In general, Staphylococci are benign members of the natural flora, but many species have the capacity to be opportunistic pathogens, mainly infecting individuals who have medical device implants or are otherwise immunocompromised. S. aureus and S. epidermidis are a major source of hospital-acquired infections and are the most common causes of surgical site infections and central line-associated bloodstream infections. The ability of Staphylococci to form biofilms in vivo makes them highly resistant to chemotherapeutics and leads to chronic diseases. These biofilm infections include osteomyelitis, endocarditis, medical device implants, and persistence in the cystic fibrosis lung. Here, we provide a comprehensive analysis of our current understanding of Staphylococcal biofilm formation, with an emphasis on adhesins and regulation, while also addressing how Staphylococcal biofilms interact with the immune system. On the whole, this review will provide a thorough picture of biofilm formation of the Staphylococcus genus and how this mode of growth impacts the host. PMID:27227309

  7. The function of TLR2 during staphylococcal diseases.

    PubMed

    Fournier, Bénédicte

    2012-01-01

    Staphylococcus aureus is a versatile pathogen causing a wide range of infections. It has been a major threat both in hospitals and in the community for decades. S. aureus is a pyogenic bacterium that elicits recruitment of polymorphonuclear leukocytes (neutrophils) to the site of infection. Neutrophils are among the first immune cells to migrate to an infection site attracted by chemoattractant gradients, usually initiated in response to inflammation. Neutrophil recruitment to an inflammation and/or infection site is a sophisticated process involving their interaction with endothelial and epithelial cells through adhesion molecules. Phagocytes have various receptors to detect pathogens, and they include Toll-like receptors (TLRs). TLRs have been extensively studied over the last 10 years and it is now established that they are critical during bacterial infections. However, the function of TLRs, and more particularly TLR2, during staphylococcal infections is still debated. In this review we will consider recent findings concerning the staphylococcal ligands sensed by TLR2 and more specifically the role of staphylococcal lipoproteins in TLR2 recognition. A new concept to emerge in recent years is that staphylococcal components must be phagocytosed and digested in the phagosome to be efficiently detected by the TLR2 of professional phagocytes. Neutrophils are an essential part of the immune response to staphylococcal infections, and in the second part of this review we will therefore describe the role of TLR2 in PMN recruitment in response to staphylococcal infections.

  8. Evolutionary origin of the staphylococcal cassette chromosome mec (SCCmec).

    PubMed

    Rolo, Joana; Worning, Peder; Nielsen, Jesper Boye; Bowden, Rory; Bouchami, Ons; Damborg, Peter; Guardabassi, Luca; Perreten, Vincent; Tomasz, Alexander; Westh, Henrik; de Lencastre, Hermínia; Miragaia, Maria

    2017-04-03

    Several lines of evidence indicate that the most primitive staphylococcal species, the Staphylococcus sciuri group, were involved in the first stages of evolution of SCCmec - the genetic element carrying the β-lactam resistance gene mecA. However, many steps are still missing from this evolutionary history. In particular, it is not known how mecA was incorporated into the mobile element SCC prior to dissemination among Staphylococcus aureus and other pathogenic staphylococcal species.To gain insights into the possible contribution of several species of the Staphylococcussciuri group to the assembly of SCCmec, we sequenced the genomes of 106 isolates, comprising S. sciuri (n=76), Staphylococcus vitulinus (n=18) and Staphylococcus fleurettii (n=12) from animal and human sources, and characterized the native location of mecA and the SCC insertion site using a variety of comparative genomic approaches. Moreover, we performed a SNP analysis of the genomes, in order to understand SCCmec evolution in relation to phylogeny.We found that each of three species of the S. sciuri group contributed to the evolution of SCCmec: S. vitulinus and S. fleurettii to the assembly of the mec complex, and S. sciuri most likely provided the mobile element in which mecA was later incorporated. We hypothesize that an ancestral SCCmec III cassette (an element carried by one of the most epidemic methicillin-resistant S. aureus clones), originated in S. sciuri possibly by a recombination event in a human host or a human-created environment and later was transferred to S. aureus.

  9. Immunotherapeutic strategies to combat staphylococcal infections.

    PubMed

    Ohlsen, Knut; Lorenz, Udo

    2010-08-01

    Antibiotic-resistant staphylococci are the leading cause of nosocomial infections in many hospitals around the world. Meanwhile, methicillin-resistant Staphylococcus aureus (MRSA) spread also in the community where highly virulent strains infect healthy adults that have no predisposing risk factors. Although a few novel antibiotics have been recently introduced into clinical practice, the search for alternative strategies to efficiently combat staphylococcal infections is urgently demanded to decrease the enormous burden caused by pathogenic staphylococci. In particular, immunological strategies based on vaccine development or therapeutic antibodies may significantly enhance the efficiency of anti-staphylococcal therapy. Most approaches are directed against surface components of staphylococci such as cell wall-linked adhesins, teichoic acids, capsule, the biofilm component PIA/PNAG, or soluble virulence determinants such as alpha-toxin, Panton-Valentine leukocidin, or superantigenic enterotoxins. Although 2 recent clinical trials have failed, several novel promising vaccines and therapeutic antibodies are currently in preclinical and clinical development.

  10. Direct, Specific and Rapid Detection of Staphylococcal Proteins and Exotoxins Using a Multiplex Antibody Microarray

    PubMed Central

    Stieber, Bettina; Monecke, Stefan; Müller, Elke; Büchler, Joseph; Ehricht, Ralf

    2015-01-01

    Background S. aureus is a pathogen in humans and animals that harbors a wide variety of virulence factors and resistance genes. This bacterium can cause a wide range of mild to life-threatening diseases. In the latter case, fast diagnostic procedures are important. In routine diagnostic laboratories, several genotypic and phenotypic methods are available to identify S. aureus strains and determine their resistances. However, there is a demand for multiplex routine diagnostic tests to directly detect staphylococcal toxins and proteins. Methods In this study, an antibody microarray based assay was established and validated for the rapid detection of staphylococcal markers and exotoxins. The following targets were included: staphylococcal protein A, penicillin binding protein 2a, alpha- and beta-hemolysins, Panton Valentine leukocidin, toxic shock syndrome toxin, enterotoxins A and B as well as staphylokinase. All were detected simultaneously within a single experiment, starting from a clonal culture on standard media. The detection of bound proteins was performed using a new fluorescence reading device for microarrays. Results 110 reference strains and clinical isolates were analyzed using this assay, with a DNA microarray for genotypic characterization performed in parallel. The results showed a general high concordance of genotypic and phenotypic data. However, genotypic analysis found the hla gene present in all S. aureus isolates but its expression under given conditions depended on the clonal complex affiliation of the actual isolate. Conclusions The multiplex antibody assay described herein allowed a rapid and reliable detection of clinically relevant staphylococcal toxins as well as resistance- and species-specific markers. PMID:26624622

  11. Staphylococcal Hyaluronate Lyase: Purification and Characterization Studies

    PubMed Central

    Abramson, Carl; Friedman, Herman

    1968-01-01

    Staphylococcal hyaluronate lyase (hyaluronidase) derived from a pathogenic strain of staphylococcus was purified by means of salt fractionation with ammonium sulfate and gel filtration through Sephadex G-100. Most of the enzyme activity from concentrated culture supernatant fluids of staphylococci was obtained in a fraction precipitated by 90 to 100% saturation with ammonium sulfate. A small amount of enzyme was also precipitated by 80 to 90% saturation with the salt. The hyaluronidase-rich fractions did not contain other staphylococcal enzymes, such as coagulase, protease, lipase, and staphylokinase. These enzymes were present in the original concentrates. Molecular sieving chromatography of the partially purified enzyme by filtration through Sephadex G-100 resulted in a further increase in specific enzyme activity. However, more than one active peak was obtained after gel filtration, thus suggesting that there may be more than one molecular form of the enzyme. Immunodiffusion in agar gel of the chromatographically purified enzyme fraction, with immune serum from rabbits injected with concentrated staphylococcal culture supernatant fluids, indicated that there was one major antigen. A similar antigen, giving reactions of identity with the purified material, was present in the original culture supernatant fluid. Images PMID:4301047

  12. Host antioxidant enzymes and TLR-2 neutralization modulate intracellular survival of Staphylococcus aureus: Evidence of the effect of redox balance on host pathogen relationship during acute staphylococcal infection.

    PubMed

    Nandi, Ajeya; Bishayi, Biswadev

    2015-12-01

    Staphylococcus aureus is an important pathogen in bone disease and innate immune recognition receptor, TLR-2 is reported to be crucial for inflammatory bone loss. Role of TLR-2 in bacterial clearance and cytokine response to S. aureus infection in murine bone marrow macrophages has been reported but the role of host derived ROS in host-pathogen relationship still remains an obvious question. In the present study, blocking of SOD and catalase in TLR-2 neutralized fresh bone marrow cells (FBMC) with Diethyldithiocarbamic acid (DDC) and 3-Amino-1,2,4-triazole (ATZ), separately, during acute S. aureus infection, produces moderate level of ROS and limits inflammation as compared with only TLR-2 non-neutralized condition and leads to decreased bacterial count compared with only TLR-2 neutralized condition. In summary, host SOD and catalase modulates ROS generation, cytokine levels and TLR-2 expression in FBMCs during acute S. aureus infection which might be useful in the alleviation of S. aureus infection and bone loss.

  13. Lincomycin and Staphylococcal Infections

    PubMed Central

    Grondin, Carrol; St-Martin, M.; Potvin, Andre

    1965-01-01

    Lincomycin, a chemically new antibiotic effective against Gram-positive organisms, was evaluated in vitro and tested clinically. In vitro testing indicated that lincomycin is especially effective against Staphylococcus aureus. Clinical testing showed that lincomycin was free of toxicity in a series of 18 cases of staphylococcal infection. Of particular interest was its pronounced effectiveness in nine cases of chronic osteomyelitis, one of which was of 15 years' duration and unresponsive to all other forms of antibiotic and surgical treatment. The only side effect noted was loose stools in the occasional patient. PMID:14281088

  14. Database of host-pathogen and related species interactions, and their global distribution.

    PubMed

    Wardeh, Maya; Risley, Claire; McIntyre, Marie Kirsty; Setzkorn, Christian; Baylis, Matthew

    2015-01-01

    Interactions between species, particularly where one is likely to be a pathogen of the other, as well as the geographical distribution of species, have been systematically extracted from various web-based, free-access sources, and assembled with the accompanying evidence into a single database. The database attempts to answer questions such as what are all the pathogens of a host, and what are all the hosts of a pathogen, what are all the countries where a pathogen was found, and what are all the pathogens found in a country. Two datasets were extracted from the database, focussing on species interactions and species distribution, based on evidence published between 1950-2012. The quality of their evidence was checked and verified against well-known, alternative, datasets of pathogens infecting humans, domestic animals and wild mammals. The presented datasets provide a valuable resource for researchers of infectious diseases of humans and animals, including zoonoses.

  15. Database of host-pathogen and related species interactions, and their global distribution

    PubMed Central

    Wardeh, Maya; Risley, Claire; McIntyre, Marie Kirsty; Setzkorn, Christian; Baylis, Matthew

    2015-01-01

    Interactions between species, particularly where one is likely to be a pathogen of the other, as well as the geographical distribution of species, have been systematically extracted from various web-based, free-access sources, and assembled with the accompanying evidence into a single database. The database attempts to answer questions such as what are all the pathogens of a host, and what are all the hosts of a pathogen, what are all the countries where a pathogen was found, and what are all the pathogens found in a country. Two datasets were extracted from the database, focussing on species interactions and species distribution, based on evidence published between 1950–2012. The quality of their evidence was checked and verified against well-known, alternative, datasets of pathogens infecting humans, domestic animals and wild mammals. The presented datasets provide a valuable resource for researchers of infectious diseases of humans and animals, including zoonoses. PMID:26401317

  16. Identification of Clinical Staphylococcal Isolates from Humans by Internal Transcribed Spacer PCR

    PubMed Central

    Couto, Isabel; Pereira, Sandro; Miragaia, Maria; Sanches, Ilda Santos; de Lencastre, Hermínia

    2001-01-01

    The emergence of coagulase-negative staphylococci not only as human pathogens but also as reservoirs of antibiotic resistance determinants requires the deployment and development of methods for their rapid and reliable identification. Internal transcribed spacer-PCR (ITS-PCR) was used to identify a collection of 617 clinical staphylococcal isolates. The amplicons were resolved in high-resolution agarose gels and visually compared with the patterns obtained for the control strains of 29 staphylococcal species. Of the 617 isolates studied, 592 (95.95%) were identified by ITS-PCR and included 11 species: 302 isolates of Staphylococcus epidermidis, 157 of S. haemolyticus, 79 of S. aureus, 21 of S. hominis, 14 of S. saprophyticus, 8 of S. warneri, 6 of S. simulans, 2 of S. lugdunensis, and 1 each of S. caprae, S. carnosus, and S. cohnii. All species analyzed had unique ITS-PCR patterns, although some were very similar, namely, the group S. saprophyticus, S. cohnii, S. gallinarum, S. xylosus, S. lentus, S. equorum, and S. chromogenes, the pair S. schleiferi and S. vitulus, and the pair S. piscifermentans and S. carnosus. Four species, S. aureus, S. caprae, S. haemolyticus, and S. lugdunensis, showed polymorphisms on their ITS-PCR patterns. ITS-PCR proved to be a valuable alternative for the identification of staphylococci, offering, within the same response time and at lower cost, higher reliability than the currently available commercial systems. PMID:11526135

  17. The pathogen biology, identification and management of Rhizoctonia species with emphasis on isolates infecting turfgrasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    R. solani is an economically important soilborne basidiomycetous pathogen of worldwide distribution and it is known to attack at least 188 species of higher plants, including crops, vegetables, ornamentals, forest trees and turfgrasses. The pathogenic isolates may belong to multiple genera and speci...

  18. Analyzing the Differences and Preferences of Pathogenic and Nonpathogenic Prokaryote Species

    NASA Astrophysics Data System (ADS)

    Nolen, L.; Duong, K.; Heim, N. A.; Payne, J.

    2015-12-01

    A limited amount of knowledge exists on the large-scale characteristics and differences of pathogenic species in comparison to all prokaryotes. Pathogenic species, like other prokaryotes, have attributes specific to their environment and lifestyles. However, because they have evolved to coexist inside their hosts, the conditions they occupy may be more limited than those of non-pathogenic species. In this study we investigate the possibility of divergent evolution between pathogenic and non-pathogenic species by examining differences that may have evolved as a result of the need to adapt to their host. For this research we analyzed data collected from over 1900 prokaryotic species and performed t-tests using R to quantify potential differences in preferences. To examine the possible divergences from nonpathogenic bacteria, we focused on three variables: cell biovolume, preferred environmental pH, and preferred environmental temperature. We also looked at differences between pathogenic and nonpathogenic species belonging to the same phylum. Our results suggest a strong divergence in abiotic preferences between the two groups, with pathogens occupying a much smaller range of temperatures and pHs than their non-pathogenic counterparts. However, while the median biovolume is different when comparing pathogens and nonpathogens, we cannot conclude that the mean values are significantly different from each other. In addition, we found evidence of convergent evolution, as the temperature and pH preferences of pathogenic bacteria species from different phlya all approach the same values. Pathogenic species do not, however, all approach the same biovolume values, suggesting that specific pH and temperature preferences are more characteristic of pathogens than certain biovolumes.

  19. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira

    PubMed Central

    Fouts, Derrick E.; Matthias, Michael A.; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E.; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L.; Haake, David A.; Haft, Daniel H.; Hartskeerl, Rudy; Ko, Albert I.; Levett, Paul N.; Matsunaga, James; Mechaly, Ariel E.; Monk, Jonathan M.; Nascimento, Ana L. T.; Nelson, Karen E.; Palsson, Bernhard; Peacock, Sharon J.; Picardeau, Mathieu; Ricaldi, Jessica N.; Thaipandungpanit, Janjira; Wunder, Elsio A.; Yang, X. Frank; Zhang, Jun-Jie; Vinetz, Joseph M.

    2016-01-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade’s refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  20. Cello-oligosaccharides released from host plants induce pathogenicity in scab-causing Streptomyces species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thaxtomin, a phytotoxic dipeptide that inhibits cellulose synthesis in expanding plant cells, is a pathogenicity determinant in scab-causing Streptomyces species. Cellobiose and cellotriose, the smallest subunits of cellulose, stimulated thaxtomin production in a defined medium, while other oligosa...

  1. Species interactions in occurrence data for a community of tick-transmitted pathogens

    PubMed Central

    Estrada-Peña, Agustín; de la Fuente, José

    2016-01-01

    Interactions between tick species, their realized range of hosts, the pathogens they carry and transmit, and the geographic distribution of species in the Western Palearctic were determined based on evidence published between 1970–2014. These relationships were linked to remotely sensed features of temperature and vegetation and used to extract the network of interactions among the organisms. The resulting datasets focused on niche overlap among ticks and hosts, species interactions, and the fraction of the environmental niche in which tick-borne pathogens may circulate as a result of interactions and overlapping environmental traits. The resulting datasets provide a valuable resource for researchers interested in tick-borne pathogens, as they conciliate the abiotic and biotic sides of their niche, allowing exploration of the importance of each host species acting as a vertebrate reservoir in the circulation of tick-transmitted pathogens in the environmental niche. PMID:27479213

  2. REAL-TIME PCR DETECTION OF THREE HUMAN-PATHOGENIC SPECIES FROM THE MICROSPORIDIAL GENUS ENCEPHALITOZOON

    EPA Science Inventory

    Three microsporidial species from the genus Encephalitozoon, E. hellem, E. cuniculi and E. intestinalis, have emerged as important opportunistic pathogens of humans affecting organ transplant recipients, AIDS patients, and other immunocompromised patients. Even though these thre...

  3. Extrolites of Aspergillus fumigatus and Other Pathogenic Species in Aspergillus Section Fumigati

    PubMed Central

    Frisvad, Jens C.; Larsen, Thomas O.

    2016-01-01

    Aspergillus fumigatus is an important opportunistic human pathogen known for its production of a large array of extrolites. Up to 63 species have been described in Aspergillus section Fumigati, some of which have also been reliably reported to be pathogenic, including A. felis, A. fischeri, A. fumigatiaffinis, A. fumisynnematus, A. hiratsukae, A. laciniosus, A. lentulus, A. novofumigatus, A. parafelis, A. pseudofelis, A. pseudoviridinutans, A. spinosus, A. thermomutatus, and A. udagawae. These species share the production of hydrophobins, melanins, and siderophores and ability to grow well at 37°C, but they only share some small molecule extrolites, that could be important factors in pathogenicity. According to the literature gliotoxin and other exometabolites can be contributing factors to pathogenicity, but these exometabolites are apparently not produced by all pathogenic species. It is our hypothesis that species unable to produce some of these metabolites can produce proxy-exometabolites that may serve the same function. We tabulate all exometabolites reported from species in Aspergillus section Fumigati and by comparing the profile of those extrolites, suggest that those producing many different kinds of exometabolites are potential opportunistic pathogens. The exometabolite data also suggest that the profile of exometabolites are highly specific and can be used for identification of these closely related species. PMID:26779142

  4. Mechanisms of staphylococcal enterotoxin-induced emesis.

    PubMed

    Hu, Dong-Liang; Nakane, Akio

    2014-01-05

    Pathogenic bacteria use various strategies to interact with the host organisms. Among them, toxin production constitutes an efficient way to alter specific functions of target cells. Various enterotoxins interact with the enteric nervous system, by stimulating afferent neurons or inducing neurotransmitter release from enterochromaffin cells which result either in vomiting, diarrhea, or in the intestinal inflammation process. Staphylococcus aureus produces a wide variety of toxins including staphylococcal enterotoxins (SEs) with demonstrated emetic activity; and staphylococcal enterotoxin-like (SEl) proteins, which are not emetic in a primate model or have yet to be tested. SEs and SEls have been traditionally subdivided into classical (SEA to SEE) and new (SEG to SElX) types. These toxins possess superantigenic activity and are highly resistant to denaturation which allows them to remain intact in contaminated foods and trigger food poisoning outbreaks. Symptoms are of rapid onset, and include nausea and violent vomiting. SEA is the most recognizable toxin causing food poisoning in humans throughout the world. However, it remains unclear how SEs induce emesis and via which signal pathway. This review is divided into four parts, and will focus on the following: (1) how bacterial toxins interact with the nervous system, (2) biological characteristics of SEs and SEls, (3) mechanisms of SE-induced emesis, and (4) use of a vaccine for the prevention of SE-induced emesis.

  5. Emerging agents of phaeohyphomycosis: pathogenic species of Bipolaris and Exserohilum.

    PubMed Central

    McGinnis, M R; Rinaldi, M G; Winn, R E

    1986-01-01

    Study of numerous living isolates of Bipolaris, Drechslera, Exserohilum, and Helminthosporium spp., as well as a mycological assessment of published case reports of phaeohyphomycosis attributed to these fungi, showed that Bipolaris australiensis, B. hawaiiensis, B. spicifera, Exserohilum longirostratum, E. mcginnisii, and E. rostratum are well-documented pathogens. Conidial shape, septation, and size, hilar characteristics, the origin of the germ tube from the basal cell and, to a lesser extent, from other conidial cells, and the sequence and location of the conidial septa are useful criteria for distinguishing these taxa. Images PMID:3745423

  6. Antibiotic Therapy of Staphylococcal Infections

    PubMed Central

    Hawks, Gordon H.

    1965-01-01

    The antibiotic treatment of staphylococcal infections remains a problem. Isolation of the organism and sensitivity testing are necessary in the choice of antibiotic. Penicillin G is the most effective penicillin against non-penicillinase-producing staphy-lococci; for the penicillinase producers there is very little to choose between the semisynthetic penicillins, methicillin, cloxacillin, nafcillin and oxacillin. For patients who are hypersensitive to penicillin, the bacteriostatic drugs (erythromycin, novobiocin, tetracycline, chloramphenicol, oleandomycin) are useful for mild infections, while for more severe illness the bactericidal drugs (vancomycin, ristocetin, kanamycin, bacitracin, neomycin) have been used successfully. Acute staphylococcal enterocolitis is probably best treated by a semisynthetic penicillin. Other antibiotics which have been found useful, with clinical trials, for staphylococcal infections are cephalosporin, fucidin, cephaloridine and lincomycin. The latter drug has been reported of value in the treatment of osteomyelitis. There is little justification for the prophylactic use of antibiotics to prevent staphylococcal infection. Surgical drainage is still an important adjunct in the treatment of many staphylococcal infections. PMID:5318575

  7. Pathogenicity of the Korean H5N8 highly pathogenic avian influenza virus in commercial domestic poultry species.

    PubMed

    Lee, Dong-Hun; Kwon, Jung-Hoon; Noh, Jin-Yong; Park, Jae-Keun; Yuk, Seong-Su; Erdene-Ochir, Tseren-Ochir; Lee, Joong-Bok; Park, Seung-Yong; Choi, In-Soo; Lee, Sang-Won; Song, Chang-Seon

    2016-01-01

    In 2014, the highly pathogenic avian influenza (HPAI) virus H5N8 triggered outbreaks in wild birds and poultry farms in South Korea. In the present study, we investigated the pathogenicity of the H5N8 HPAI virus, belonging to the clade 2.3.4.4, in different species of poultry. For this, we examined clinical signs and viral shedding levels following intranasal inoculation of the virus in 3-week-old commercial layer chickens and quails, 10-week-old Korean native chickens, and 8-week-old Muscovy ducks. Intranasal inoculation with 10(6.0) viruses at 50% egg-infective dose resulted in 100% mortality in the layer chickens (8/8) and quails (4/4), but 60% and 0% deaths in the Korean native chickens (3/5) and Muscovy ducks (0/4), respectively. In addition, transmission of the inoculated virus to contact-exposed birds was evident in all the species used in this study. Based on our results, we conclude that the H5N8 HPAI virus has lower pathogenicity and transmissibility in poultry species compared with previously reported H5N1 HPAI viruses.

  8. Controls on pathogen species richness in plants introduced and native ranges: roles of residence time, range size and host traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction of hosts to new geographic regions allows them to escape many pathogens, raising two questions. How quickly do introduced hosts accumulate pathogens? Do the same factors control pathogen accumulation as in the native range? We analyzed fungal and viral pathogen species richness on 124 p...

  9. The effect of soil-borne pathogens depends on the abundance of host tree species

    PubMed Central

    Liu, Yu; Fang, Suqin; Chesson, Peter; He, Fangliang

    2015-01-01

    The overarching issue for understanding biodiversity maintenance is how fitness advantages accrue to a species as it becomes rare, as this is the defining feature of stable coexistence mechanisms. Without these fitness advantages, average fitness differences between species will lead to exclusion. However, empirical evidence is lacking, especially for forests, due to the difficulty of manipulating density on a large-enough scale. Here we took advantage of naturally occurring contrasts in abundance between sites of a subtropical tree species, Ormosia glaberrima, to demonstrate how low-density fitness advantages accrue by the Janzen–Connell mechanism. The results showed that soil pathogens suppressed seedling recruitment of O. glaberrima when it is abundant but had little effect on the seedlings when it is at low density due to the lack of pathogens. The difference in seedling survival between abundant and low-density sites demonstrates strong dependence of pathogenic effect on the abundance of host species. PMID:26632594

  10. Mycobacterium mantenii sp. nov., a pathogenic, slowly growing, scotochromogenic species.

    PubMed

    van Ingen, Jakko; Lindeboom, Jerome A; Hartwig, Nico G; de Zwaan, Rina; Tortoli, Enrico; Dekhuijzen, P N Richard; Boeree, Martin J; van Soolingen, Dick

    2009-11-01

    Slowly growing, scotochromogenic bacteria of a novel Mycobacterium species were isolated from lymph node samples in two children and pulmonary samples in two elderly patients from different regions in the Netherlands as well as from a surface water sample in Zambia. Its 16S rRNA gene, 16S-23S internal transcribed spacer (ITS), hsp65 and rpoB gene sequences are unique in comparison with other mycobacteria. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that these micro-organisms are most closely related to Mycobacterium scrofulaceum ATCC 19981(T) (8 differences; 0.6 % divergence). The hsp65 sequence shows 96 % similarity to that of Mycobacterium saskatchewanense MB54784 and the rpoB sequence shows 95 % similarity to that of Mycobacterium chimaera CIP 107892(T). The 16S-23S ITS sequence places these micro-organisms within the Mycobacterium avium complex, as a novel ITS sequevar. This is not supported by analysis of the 16S rRNA, hsp65 or rpoB gene sequences. Their scotochromogenicity, combined with mostly positive urease, positive semiquantitative catalase and negative tellurite reduction tests, set these isolates apart from related species. The mycolic acid patterns, obtained by HPLC, are similar to that of Mycobacterium scrofulaceum, though the peak heights and distribution present minor differences. We propose the name Mycobacterium mantenii sp. nov. for this novel species. The type strain, isolated from a lymph node biopsy sample, is strain 04-1474(T) (=NLA000401474(T) =CIP 109863(T) =DSM 45255(T)).

  11. Gene Loss Dominates As a Source of Genetic Variation within Clonal Pathogenic Bacterial Species.

    PubMed

    Bolotin, Evgeni; Hershberg, Ruth

    2015-07-10

    Some of the most dangerous pathogens such as Mycobacterium tuberculosis and Yersinia pestis evolve clonally. This means that little or no recombination occurs between strains belonging to these species. Paradoxically, although different members of these species show extreme sequence similarity of orthologous genes, some show considerable intraspecies phenotypic variation, the source of which remains elusive. To examine the possible sources of phenotypic variation within clonal pathogenic bacterial species, we carried out an extensive genomic and pan-genomic analysis of the sources of genetic variation available to a large collection of clonal and nonclonal pathogenic bacterial species. We show that while nonclonal species diversify through a combination of changes to gene sequences, gene loss and gene gain, gene loss completely dominates as a source of genetic variation within clonal species. Indeed, gene loss is so prevalent within clonal species as to lead to levels of gene content variation comparable to those found in some nonclonal species that are much more diverged in their gene sequences and that acquire a substantial number of genes horizontally. Gene loss therefore needs to be taken into account as a potential dominant source of phenotypic variation within clonal bacterial species.

  12. Chlamydial infections of fish: diverse pathogens and emerging causes of disease in aquaculture species.

    PubMed

    Stride, M C; Polkinghorne, A; Nowak, B F

    2014-05-14

    Chlamydial infections of fish are emerging as an important cause of disease in new and established aquaculture industries. To date, epitheliocystis, a skin and gill disease associated with infection by these obligate intracellular pathogens, has been described in over 90 fish species, including hosts from marine and fresh water environments. Aided by advances in molecular detection and typing, recent years have seen an explosion in the description of these epitheliocystis-related chlamydial pathogens of fish, significantly broadening our knowledge of the genetic diversity of the order Chlamydiales. Remarkably, in most cases, it seems that each new piscine host studied has revealed the presence of a phylogenetically unique and novel chlamydial pathogen, providing researchers with a fascinating opportunity to understand the origin, evolution and adaptation of their traditional terrestrial chlamydial relatives. Despite the advances in this area, much still needs to be learnt about the epidemiology of chlamydial infections in fish if these pathogens are to be controlled in farmed environments. The lack of in vitro methods for culturing of chlamydial pathogens of fish is a major hindrance to this field. This review provides an update on our current knowledge of the taxonomy and diversity of chlamydial pathogens of fish, discusses the impact of these infections on the health, and highlights further areas of research required to understand the biology and epidemiology of this important emerging group of fish pathogens of aquaculture species.

  13. Chlamydial infections of fish: diverse pathogens and emerging causes of disease in aquaculture species.

    PubMed

    Stride, M C; Polkinghome, A; Nowak, B F

    2014-06-25

    Chlamydial infections of fish are emerging as an important cause of disease in new and established aquaculture industries. To date, epitheliocystis, a skin and gill disease associated with infection by these obligate intracellular pathogens, has been described in over 90 fish species, including hosts from marine and fresh water environments. Aided by advances in molecular detection and typing, recent years have seen an explosion in the description of these epitheliocystis-related chlamydial pathogens of fish, significantly broadening our knowledge of the genetic diversity of the order Chlamydiales. Remarkably, in most cases, it seems that each new piscine host studied has revealed the presence of a phylogenetically unique and novel chlamydial pathogen, providing researchers with a fascinating opportunity to understand the origin, evolution and adaptation of their traditional terrestrial chlamydial relatives. Despite the advances in this area, much still needs to be learnt about the epidemiology of chlamydial infections in fish if these pathogens are to be controlled in farmed environments. The lack of in vitro methods for culturing of chlamydial pathogens of fish is a major hindrance to this field. This review provides an update on our current knowledge of the taxonomy and diversity of chlamydial pathogens of fish, discusses the impact of these infections on the health, and highlights further areas of research required to understand the biology and epidemiology of this important emerging group of fish pathogens of aquaculture species.

  14. Turbidimetric Assay of Staphylococcal Nuclease

    PubMed Central

    Erickson, Alan; Deibel, R. H.

    1973-01-01

    A simplified turbidimetric procedure was developed to assay staphylococcal nuclease activity. The ease of performance and sensitivity to nanogram quantities enhance the utilization of the method for the quantitative or qualitative estimation of the enzyme. Unlike plating methods, the turbidimetric procedure affords the differentiation between heat-stable and heat-labile nuclease activity. PMID:4735446

  15. Staphylococcal food poisoning and botulism

    PubMed Central

    Gilbert, R. J.

    1974-01-01

    Staphylococcal food poisoning and botulism are caused by the ingestion of food containing exotoxins. Outbreaks of both are still a problem in many countries. This paper attempts to summarize information relating to these illnesses, together with advice on how their incidence may be reduced, or better still prevented. PMID:4619651

  16. Saprophytic and Potentially Pathogenic Fusarium Species from Peat Soil in Perak and Pahang

    PubMed Central

    Karim, Nurul Farah Abdul; Mohd, Masratulhawa; Nor, Nik Mohd Izham Mohd; Zakaria, Latiffah

    2016-01-01

    Isolates of Fusarium were discovered in peat soil samples collected from peat swamp forest, waterlogged peat soil, and peat soil from oil palm plantations. Morphological characteristics were used to tentatively identify the isolates, and species confirmation was based on the sequence of translation elongation factor-1α (TEF-1α) and phylogenetic analysis. Based on the closest match of Basic Local Alignment Search Tool (BLAST) searches against the GenBank and Fusarium-ID databases, five Fusarium species were identified, namely F. oxysporum (60%), F. solani (23%), F. proliferatum (14%), F. semitectum (1%), and F. verticillioides (1%). From a neighbour-joining tree of combined TEF-1α and β-tubulin sequences, isolates from the same species were clustered in the same clade, though intraspecies variations were observed from the phylogenetic analysis. The Fusarium species isolated in the present study are soil inhabitants and are widely distributed worldwide. These species can act as saprophytes and decomposers as well as plant pathogens. The presence of Fusarium species in peat soils suggested that peat soils could be a reservoir of plant pathogens, as well-known plant pathogenic species such F. oxysporum, F. solani, F. proliferatum, and F. verticillioides were identified. The results of the present study provide knowledge on the survival and distribution of Fusarium species. PMID:27019679

  17. Saprophytic and Potentially Pathogenic Fusarium Species from Peat Soil in Perak and Pahang.

    PubMed

    Karim, Nurul Farah Abdul; Mohd, Masratulhawa; Nor, Nik Mohd Izham Mohd; Zakaria, Latiffah

    2016-02-01

    Isolates of Fusarium were discovered in peat soil samples collected from peat swamp forest, waterlogged peat soil, and peat soil from oil palm plantations. Morphological characteristics were used to tentatively identify the isolates, and species confirmation was based on the sequence of translation elongation factor-1α (TEF-1α) and phylogenetic analysis. Based on the closest match of Basic Local Alignment Search Tool (BLAST) searches against the GenBank and Fusarium-ID databases, five Fusarium species were identified, namely F. oxysporum (60%), F. solani (23%), F. proliferatum (14%), F. semitectum (1%), and F. verticillioides (1%). From a neighbour-joining tree of combined TEF-1α and β-tubulin sequences, isolates from the same species were clustered in the same clade, though intraspecies variations were observed from the phylogenetic analysis. The Fusarium species isolated in the present study are soil inhabitants and are widely distributed worldwide. These species can act as saprophytes and decomposers as well as plant pathogens. The presence of Fusarium species in peat soils suggested that peat soils could be a reservoir of plant pathogens, as well-known plant pathogenic species such F. oxysporum, F. solani, F. proliferatum, and F. verticillioides were identified. The results of the present study provide knowledge on the survival and distribution of Fusarium species.

  18. Non-diphtheriae Corynebacterium species: an emerging respiratory pathogen.

    PubMed

    Díez-Aguilar, M; Ruiz-Garbajosa, P; Fernández-Olmos, A; Guisado, P; Del Campo, R; Quereda, C; Cantón, R; Meseguer, M A

    2013-06-01

    The purpose of the study was to describe the microbiological and clinical features of ten cases of lower respiratory tract infection due to Corynebacterium striatum, Corynebacterium propinquum and Corynebacterium pseudodiphtheriticum. Respiratory samples were recovered from hospitalised patients who were diagnosed of pneumonia and exacerbations of chronic respiratory infections. The samples were Gram-stained and seeded on conventional bacterial growing media. Bacteria were identified by matrix-assisted linear desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility was tested by the disk diffusion method. All patients presented an acute respiratory onset, most of them in the context of an underlying disease and/or immunosuppression. In all patients, the microscopical examination of Gram-stained respiratory samples showed numerous polymorphonuclear cells and Gram-positive bacilli, suggestive of the Corynebacterium morphotype. A pure culture growth of Corynebacterium was obtained in the majority (72 %) of samples. The conclusions are that non-diphtheriae Corynebacterium species are an emerging cause of respiratory infection among patients with chronic respiratory disease and/or immunosuppression, and cannot always be considered as mere colonisers. The microorganism's predominance in Gram-stained purulent respiratory samples together with abundant growth in the culture is the key for the microbiological diagnosis.

  19. Anatomical patterns of colonization of pets with staphylococcal species in homes of people with methicillin-resistant Staphylococcus aureus (MRSA) skin or soft tissue infection (SSTI).

    PubMed

    Iverson, S A; Brazil, A M; Ferguson, J M; Nelson, K; Lautenbach, E; Rankin, S C; Morris, D O; Davis, M F

    2015-03-23

    Methicillin-resistant strains of Staphylococcus aureus (MRSA), Staphylococcus pseudintermedius (MRSP), and other pathogenic staphylococci can cause infections in companion animals and humans. Identification of colonized animals is fundamental to research and practice needs, but harmonized methods have not yet been established. To establish the optimal anatomic site for the recovery of methicillin-resistant coagulase positive staphylococci (CPS), survey data and swabs were collected from 196 pets (dogs, cats, reptiles, birds, fish and pocket pets) that lived in households with an MRSA-infected person. Using broth-enrichment culture and PCR for speciation, S. aureus was identified in 27 of 179 (15%) pets sampled at baseline and 19 of 125 (15%) pets sampled at a three-month follow-up home visit. S. pseudintermedius was isolated from 33 of 179 (18%) pets sampled at baseline and 21 of 125 (17%) of pets sampled at follow-up. The baseline MRSA and MRSP prevalence was 8% and 1% respectively from 145 mammalian pets. The follow-up MRSA and MRSP prevalence was 7% and <1% respectively from 95 mammalian pets. The mouth was the most sensitive single site sampled for isolation of S. aureus and S. pseudintermedius in mammals. In a subset of pets, from which all available isolates were identified, dual carriage of S. aureus and S. pseudintermedius was 22% at baseline and 11% at follow-up. These results identify the mouth as the most sensitive site to screen for pathogenic staphylococci and suggest that it should be included in sampling protocols.

  20. Genomic Characterization Reveals Insights Into Patulin Biosynthesis and Pathogenicity in Penicillium Species.

    PubMed

    Li, Boqiang; Zong, Yuanyuan; Du, Zhenglin; Chen, Yong; Zhang, Zhanquan; Qin, Guozheng; Zhao, Wenming; Tian, Shiping

    2015-06-01

    Penicillium species are fungal pathogens that infect crop plants worldwide. P. expansum differs from P. italicum and P. digitatum, all major postharvest pathogens of pome and citrus, in that the former is able to produce the mycotoxin patulin and has a broader host range. The molecular basis of host-specificity of fungal pathogens has now become the focus of recent research. The present report provides the whole genome sequence of P. expansum (33.52 Mb) and P. italicum (28.99 Mb) and identifies differences in genome structure, important pathogenic characters, and secondary metabolite (SM) gene clusters in Penicillium species. We identified a total of 55 gene clusters potentially related to secondary metabolism, including a cluster of 15 genes (named PePatA to PePatO), that may be involved in patulin biosynthesis in P. expansum. Functional studies confirmed that PePatL and PePatK play crucial roles in the biosynthesis of patulin and that patulin production is not related to virulence of P. expansum. Collectively, P. expansum contains more pathogenic genes and SM gene clusters, in particular, an intact patulin cluster, than P. italicum or P. digitatum. These findings provide important information relevant to understanding the molecular network of patulin biosynthesis and mechanisms of host-specificity in Penicillium species.

  1. Forest species diversity reduces disease risk in a generalist plant pathogen invasion

    USGS Publications Warehouse

    Haas, Sarah E.; Hooten, Mevin B.; Rizzo, David M.; Meentemeyer, Ross K.

    2011-01-01

    Empirical evidence suggests that biodiversity loss can increase disease transmission, yet our understanding of the 'diversity-disease hypothesis' for generalist pathogens in natural ecosystems is limited. We used a landscape epidemiological approach to examine two scenarios regarding diversity effects on the emerging plant pathogen Phytophthora ramorum across a broad, heterogeneous ecoregion: (1) an amplification effect exists where disease risk is greater in areas with higher plant diversity due to the pathogen's wide host range, or (2) a dilution effect where risk is reduced with increasing diversity due to lower competency of alternative hosts. We found evidence for pathogen dilution, whereby disease risk was lower in sites with higher species diversity, after accounting for potentially confounding effects of host density and landscape heterogeneity. Our results suggest that although nearly all plants in the ecosystem are hosts, alternative hosts may dilute disease transmission by competent hosts, thereby buffering forest health from infectious disease.

  2. Role of Intraspecies Recombination in the Spread of Pathogenicity Islands within the Escherichia coli Species

    PubMed Central

    Schubert, Sören; Darlu, Pierre; Clermont, Olivier; Wieser, Andreas; Magistro, Giuseppe; Hoffmann, Christiane; Weinert, Kirsten; Tenaillon, Olivier; Matic, Ivan; Denamur, Erick

    2009-01-01

    Horizontal gene transfer is a key step in the evolution of bacterial pathogens. Besides phages and plasmids, pathogenicity islands (PAIs) are subjected to horizontal transfer. The transfer mechanisms of PAIs within a certain bacterial species or between different species are still not well understood. This study is focused on the High-Pathogenicity Island (HPI), which is a PAI widely spread among extraintestinal pathogenic Escherichia coli and serves as a model for horizontal transfer of PAIs in general. We applied a phylogenetic approach using multilocus sequence typing on HPI-positive and -negative natural E. coli isolates representative of the species diversity to infer the mechanism of horizontal HPI transfer within the E. coli species. In each strain, the partial nucleotide sequences of 6 HPI–encoded genes and 6 housekeeping genes of the genomic backbone, as well as DNA fragments immediately upstream and downstream of the HPI were compared. This revealed that the HPI is not solely vertically transmitted, but that recombination of large DNA fragments beyond the HPI plays a major role in the spread of the HPI within E. coli species. In support of the results of the phylogenetic analyses, we experimentally demonstrated that HPI can be transferred between different E. coli strains by F-plasmid mediated mobilization. Sequencing of the chromosomal DNA regions immediately upstream and downstream of the HPI in the recipient strain indicated that the HPI was transferred and integrated together with HPI–flanking DNA regions of the donor strain. The results of this study demonstrate for the first time that conjugative transfer and homologous DNA recombination play a major role in horizontal transfer of a pathogenicity island within the species E. coli. PMID:19132082

  3. Serologic survey for cross-species pathogens in urban coyotes (Canis latrans), Colorado, USA.

    PubMed

    Malmlov, Ashley; Breck, Stewart; Fry, Tricia; Duncan, Colleen

    2014-10-01

    Abstract As coyotes (Canis latrans) adapt to living in urban environments, the opportunity for cross-species transmission of pathogens may increase. We investigated the prevalence of antibodies to pathogens that are either zoonotic or affect multiple animal species in urban coyotes in the Denver metropolitan area, Colorado, USA, in 2012. We assayed for antibodies to canine parvovirus-2, canine distemper virus, rabies virus, Toxoplasma gondii, Yersinia pestis, and serotypes of Leptospira interrogans. Overall, 84% of the animals had antibodies to canine parvovirus-2, 44% for canine distemper virus, 20% for T. gondii (IgG), 28% for Y. pestis, and 4% for L. interrogans serotype Grippotyphosa. No neutralizing antibodies were detected to rabies virus, T. gondii (IgM), or L. interrogans serotypes other than Grippotyphosa. With 88% of animals exposed to at least one pathogen, our results suggest that coyotes may serve as important reservoirs and sentinels for etiologic agents.

  4. Cadophora species as trunk pathogens and wood-infecting fungi of grapevine in North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cadophora species, in particular Cadophora luteo-olivacea, are reported from grapevine (Vitis vinifera L.) in California, South Africa, Spain, Uruguay, and Canada. Frequent isolation from vines co-infected with the Esca pathogens (Togninia minima, Phaeomoniella chlamydospora), and confirmation of it...

  5. Occurrence of putative pathogenicity islands in enterococci from distinct species and of differing origins.

    PubMed

    Semedo-Lemsaddek, Teresa; Barreto-Crespo, Maria Teresa; Tenreiro, Rogério

    2009-11-01

    Enterococci isolated from ewe's milk and cheese, clinical isolates of human and veterinary origins, and reference strains obtained from culture collections were screened for the occurrence of putative pathogenicity island (PAIs). Results obtained after PCR amplification and hybridization point toward PAI dissemination among enterococci of diverse origins (food/clinical) and species (Enterococcus faecalis/non-E. faecalis).

  6. The wild tomato species Solanum chilense shows variation in pathogen resistance between geographically distinct populations

    PubMed Central

    Scheikl, Daniela; Tellier, Aurélien

    2017-01-01

    Wild tomatoes are a valuable source of disease resistance germplasm for tomato (Solanum lycopersicum) breeders. Many species are known to possess a certain degree of resistance against certain pathogens; however, evolution of resistance traits is yet poorly understood. For some species, like Solanum chilense, both differences in habitat and within species genetic diversity are very large. Here we aim to investigate the occurrence of spatially heterogeneous coevolutionary pressures between populations of S. chilense. We investigate the phenotypic differences in disease resistance within S. chilense against three common tomato pathogens (Alternaria solani, Phytophthora infestans and a Fusarium sp.) and confirm high degrees of variability in resistance properties between selected populations. Using generalised linear mixed models, we show that disease resistance does not follow the known demographic patterns of the species. Models with up to five available climatic and geographic variables are required to best describe resistance differences, confirming the complexity of factors involved in local resistance variation. We confirm that within S. chilense, resistance properties against various pathogens show a mosaic pattern and do not follow environmental patterns, indicating the strength of local pathogen pressures. Our study can form the basis for further investigations of the genetic traits involved. PMID:28133579

  7. Evolutionary study of Yersinia genomes deciphers emergence of human pathogenic species

    PubMed Central

    Tan, Shi Yang; Tan, Irene Kit Ping; Tan, Mui Fern; Dutta, Avirup; Choo, Siew Woh

    2016-01-01

    On record, there are 17 species in the Yersinia genus, of which three are known to be pathogenic to human. While the chromosomal and pYV (or pCD1) plasmid-borne virulence genes as well as pathogenesis of these three species are well studied, their genomic evolution is poorly understood. Our study aims to predict the key evolutionary events that led to the emergence of pathogenic Yersinia species by analyzing gene gain-and-loss, virulence genes, and “Clustered regularly-interspaced short palindromic repeats”. Our results suggest that the most recent ancestor shared by the human pathogenic Yersinia was most probably an environmental species that had adapted to the human body. This might have led to ecological specialization that diverged Yersinia into ecotypes and distinct lineages based on differential gene gain-and-loss in different niches. Our data also suggest that Y. pseudotuberculosis group might be the donor of the ail virulence gene to Y. enterocolitica. Hence, we postulate that evolution of human pathogenic Yersinia might not be totally in parallel, but instead, there were lateral gene transfer events. Furthermore, the presence of virulence genes seems to be important for the positive selection of virulence plasmid. Our studies provide better insights into the evolutionary biology of these bacteria. PMID:27796355

  8. Integrative conjugative elements are widespread in field isolates of Mycoplasma species pathogenic for ruminants.

    PubMed

    Tardy, Florence; Mick, Virginie; Dordet-Frisoni, Emilie; Marenda, Marc Serge; Sirand-Pugnet, Pascal; Blanchard, Alain; Citti, Christine

    2015-03-01

    Comparative genomics have revealed massive horizontal gene transfer (HGT) between Mycoplasma species sharing common ruminant hosts. Further results pointed toward an integrative conjugative element (ICE) as an important contributor of HGT in the small-ruminant-pathogen Mycoplasma agalactiae. To estimate the prevalence of ICEs in ruminant mycoplasmas, we surveyed their occurrence in a collection of 166 field strains representing 4 (sub)species that are recognized as major pathogens. Based on available sequenced genomes, we first defined the conserved, minimal ICE backbone as composed of 4 coding sequences (CDSs) that are evenly distributed and predicted to be essential for ICE chromosomal integration-excision and horizontal transfer. Screening of the strain collection revealed that these 4 CDSs are well represented in ruminant Mycoplasma species, suggesting widespread occurrence of ICEs. Yet their prevalence varies within and among species, with no correlation found with the individual strain history. Extrachromosomal ICE forms were also often detected, suggesting that ICEs are able to circularize in all species, a first and essential step in ICE horizontal transfer. Examination of the junction of the circular forms and comparative sequence analysis of conserved CDSs clearly pointed toward two types of ICE, the hominis and spiroplasma types, most likely differing in their mechanism of excision-integration. Overall, our data indicate the occurrence and maintenance of functional ICEs in a large number of field isolates of ruminant mycoplasmas. These may contribute to genome plasticity and gene exchanges and, presumably, to the emergence of diverse genotypes within pathogenic mycoplasmas of veterinary importance.

  9. Antibodies to some pathogenic agents in free-living wild species in Tanzania.

    PubMed

    Hamblin, C; Anderson, E C; Jago, M; Mlengeya, T; Hipji, K

    1990-12-01

    A total of 535 sera from eight species of wildlife were collected from different game areas in Tanzania between 1987 and 1989. These sera were tested for antibodies against foot-and-mouth disease, bovine herpes virus types 1 and 2, lumpy skin disease, bovine viral diarrhoea, Akabane, bovine ephemeral fever, bluetongue, enzootic bovine leucosis, African horse sickness and African swine fever viruses and Brucella abortus based on the expected species susceptibility. Sera from buffalo Syncerus caffer, wildebeest Connochaetes taurinus and topi Damaliscus korrigum contained antibodies against the majority of the pathogens tested. Antibodies to fewer pathogens were detected in sera from the other species. No antibodies to lumpy skin disease virus were detected in any of the sera examined. African horse sickness antibodies were detected in sera from Zebra and African swine fever antibodies were detected in wart hog. The occurrence of antibodies to these agents suggests that wild species act as reservoirs of infection for some of these pathogens. However, until the susceptibility of individual species is proven by isolation of the aetiological agents their role must remain speculative.

  10. Development of a DNA-based microarray for the detection of zoonotic pathogens in rodent species.

    PubMed

    Giles, Timothy; Yon, Lisa; Hannant, Duncan; Barrow, Paul; Abu-Median, Abu-Bakr

    2015-12-01

    The demand for diagnostic tools that allow simultaneous screening of samples for multiple pathogens is increasing because they overcome the limitations of other methods, which can only screen for a single or a few pathogens at a time. Microarrays offer the advantages of being capable to test a large number of samples simultaneously, screening for multiple pathogen types per sample and having comparable sensitivity to existing methods such as PCR. Array design is often considered the most important process in any microarray experiment and can be the deciding factor in the success of a study. There are currently no microarrays for simultaneous detection of rodent-borne pathogens. The aim of this report is to explicate the design, development and evaluation of a microarray platform for use as a screening tool that combines ease of use and rapid identification of a number of rodent-borne pathogens of zoonotic importance. Nucleic acid was amplified by multiplex biotinylation PCR prior to hybridisation onto microarrays. The array sensitivity was comparable to standard PCR, though less sensitive than real-time PCR. The array presented here is a prototype microarray identification system for zoonotic pathogens that can infect rodent species.

  11. Comparative Genomic Analysis Reveals a Possible Novel Non-Tuberculous Mycobacterium Species with High Pathogenic Potential

    PubMed Central

    Choo, Siew Woh; Dutta, Avirup; Wong, Guat Jah; Wee, Wei Yee; Ang, Mia Yang; Siow, Cheuk Chuen

    2016-01-01

    Mycobacteria have been reported to cause a wide range of human diseases. We present the first whole-genome study of a Non-Tuberculous Mycobacterium, Mycobacterium sp. UM_CSW (referred to hereafter as UM_CSW), isolated from a patient diagnosed with bronchiectasis. Our data suggest that this clinical isolate is likely a novel mycobacterial species, supported by clear evidence from molecular phylogenetic, comparative genomic, ANI and AAI analyses. UM_CSW is closely related to the Mycobacterium avium complex. While it has characteristic features of an environmental bacterium, it also shows a high pathogenic potential with the presence of a wide variety of putative genes related to bacterial virulence and shares very similar pathogenomic profiles with the known pathogenic mycobacterial species. Thus, we conclude that this possible novel Mycobacterium species should be tightly monitored for its possible causative role in human infections. PMID:27035710

  12. Mechanisms of Disease: Host-Pathogen Interactions between Burkholderia Species and Lung Epithelial Cells

    PubMed Central

    David, Jonathan; Bell, Rachel E.; Clark, Graeme C.

    2015-01-01

    Members of the Burkholderia species can cause a range of severe, often fatal, respiratory diseases. A variety of in vitro models of infection have been developed in an attempt to elucidate the mechanism by which Burkholderia spp. gain entry to and interact with the body. The majority of studies have tended to focus on the interaction of bacteria with phagocytic cells with a paucity of information available with regard to the lung epithelium. However, the lung epithelium is becoming more widely recognized as an important player in innate immunity and the early response to infections. Here we review the complex relationship between Burkholderia species and epithelial cells with an emphasis on the most pathogenic species, Burkholderia pseudomallei and Burkholderia mallei. The current gaps in knowledge in our understanding are highlighted along with the epithelial host-pathogen interactions that offer potential opportunities for therapeutic intervention. PMID:26636042

  13. Antigenic relationship between the animal and human pathogen Pythium insidiosum and nonpathogenic Pythium species.

    PubMed Central

    Mendoza, L; Kaufman, L; Standard, P

    1987-01-01

    Identification of the newly named pathogenic oomycete Pythium insidiosum and its differentiation from other Pythium species by morphologic criteria alone can be difficult and time-consuming. Antigenic analysis by fluorescent-antibody and immunodiffusion precipitin techniques demonstrated that the P. insidiosum isolates that cause pythiosis in dogs, horses, and humans are identical and that they were distinguishable from other Pythium species by these means. The immunologic data agreed with the morphologic data. This indicated that the animal and human isolates belonged to a single species, P. insidiosum. Fluorescent-antibody and immunodiffusion reagents were developed for the specific identification of P. insidiosum. PMID:3121666

  14. Pathogenic Acinetobacter Species have a Functional Type I Secretion System and Contact-Dependent Inhibition Systems.

    PubMed

    Harding, Christian M; Pulido, Marina R; Di Venanzio, Gisela; Kinsella, Rachel L; Webb, Andrew I; Scott, Nichollas E; Pachón, Jerónimo; Feldman, Mario F

    2017-04-03

    Pathogenic Acinetobacter species, including A. baumannii and A. nosocomialis, are opportunistic human pathogens of increasing relevance worldwide. Although their mechanisms of drug resistance are well studied, the virulence factors that govern Acinetobacter pathogenesis are incompletely characterized. Here we define the complete secretome of A. nosocomialis strain M2 in minimal media and demonstrate that pathogenic Acinetobacter species produce both a functional type I secretion system (T1SS) and a contact dependent inhibition (CDI) system. Using bioinformatics, quantitative proteomics, and mutational analyses we show that Acinetobacter uses its T1SS for exporting two putative T1SS effectors, an RTX-Serralysin-like toxin and the biofilm associated protein (Bap). Moreover, we found that mutation of any component of the T1SS system abrogated type VI secretion activity under nutrient-limited conditions, indicating a previously unrecognized crosstalk between these two systems. We also demonstrate that the Acinetobacter T1SS is required for biofilm formation. Lastly, we show that both A. nosocomialis and A. baumannii produce functioning CDI systems that mediate growth inhibition of sister cells lacking the cognate immunity protein. The Acinetobacter CDI systems are widely distributed across pathogenic Acinetobacter species, with many A. baumannii isolates harboring two distinct CDI systems. Collectively, these data demonstrate the power of differential, quantitative proteomics approaches to study secreted proteins, define the role of previously uncharacterized protein export systems, and observe crosstalk between secretion systems in the pathobiology of medically relevant Acinetobacter The data are available via ProteomeXchange with identifier PXD005881.

  15. The Use of Laser-Induced Breakdown Spectroscopy for Distinguishing Between Bacterial Pathogen Species and Strains

    PubMed Central

    Multari, Rosalie A.; Cremers, David A.; Dupre, Joanne M.; Gustafson, John E.

    2013-01-01

    Laser-induced breakdown spectroscopy (LIBS) was used in a blind study to successfully differentiate bacterial pathogens, both species and strain. The pathogens used for the study were chosen and prepared by one set of researchers. The LIBS data were collected and analyzed by another set of researchers. The latter researchers had no knowledge of the sample identities other than that (1) the first five of fifteen samples were unique (not replicates) and (2) the remaining ten samples consisted of two replicates of each of the first five samples. Using only chemometric analysis of the LIBS data, the ten replicate bacterial samples were successfully matched to each of the first five samples. The results of this blind study show it is possible to differentiate the bacterial pathogens Escherichia coli, three clonal methicillin-resistant Staphylococcus aureus (MRSA) strains, and one unrelated MRSA strain using LIBS. This is an important finding because it demonstrates that LIBS can be used to determine bacterial pathogen species within a defined sample set and can be used to differentiate between clonal relationships among strains of a single multiple-antibiotic-resistant bacterial species. Such a capability is important for the development of LIBS instruments for use in medical, water, and food safety applications. PMID:20615288

  16. Prevalence of Cyclospora species and other enteric pathogens among children less than 5 years of age in Nepal.

    PubMed Central

    Hoge, C W; Echeverria, P; Rajah, R; Jacobs, J; Malthouse, S; Chapman, E; Jimenez, L M; Shlim, D R

    1995-01-01

    Stools from 124 Nepalese children aged 6 to 60 months with diarrhea were examined for organisms of the coccidian genus Cyclospora and for other enteric pathogens. Enterotoxigenic Escherichia coli, Giardia Lamblia, Campylobacter species, Cyclospora species, and Cryptosporidium species were the most common pathogens identified. Cyclospora species were detected in none of 74 children < 18 months of age compared with 6 (12%) of 50 children > or = 18 months of age (P = 0.004). PMID:8576377

  17. The olive compound 4-hydroxytyrosol inactivates Staphyloccoccus aureus bacteria and Staphylococcal enterotoxin A (SEA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal enterotoxin A (SEA), a single chain protein which consists of 233 amino acid residues with a molecular weight of 27,078 Da. SEA is a superantigen that is reported to contribute to animal (mastitis) and human (emesis, ...

  18. Inhibition of Biological Activity of Staphylococcal Enterotoxin A (SEA) by Apple Juice and Apple Polyphenols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal entertoxin A (SEA), a single-chain protein that consists of 233 amino acid residues with a molecular weight of 27 078 Da. SEA is a superantigen that is reported to contribute to animal (mastitis) and human (emesis, dia...

  19. Species or Genotypes? Reassessment of Four Recently Described Species of the Ceratocystis Wilt Pathogen, Ceratocystis fimbriata, on Mangifera indica.

    PubMed

    Oliveira, Leonardo S S; Harrington, Thomas C; Ferreira, Maria A; Damacena, Michelle B; Al-Sadi, Abdullah M; Al-Mahmooli, Issa H S; Alfenas, Acelino C

    2015-09-01

    Ceratocystis wilt is among the most important diseases on mango (Mangifera indica) in Brazil, Oman, and Pakistan. The causal agent was originally identified in Brazil as Ceratocystis fimbriata, which is considered by some as a complex of many cryptic species, and four new species on mango trees were distinguished from C. fimbriata based on variation in internal transcribed spacer sequences. In the present study, phylogenetic analyses using DNA sequences of mating type genes, TEF-1α, and β-tubulin failed to identify lineages corresponding to the four new species names. Further, mating experiments found that the mango isolates representing the new species were interfertile with each other and a tester strain from sweet potato (Ipomoea batatas), on which the name C. fimbriata is based, and there was little morphological variation among the mango isolates. Microsatellite markers found substantial differentiation among mango isolates at the regional and population levels, but certain microsatellite genotypes were commonly found in multiple populations, suggesting that these genotypes had been disseminated in infected nursery stock. The most common microsatellite genotypes corresponded to the four recently named species (C. manginecans, C. acaciivora, C. mangicola, and C. mangivora), which are considered synonyms of C. fimbriata. This study points to the potential problems of naming new species based on introduced genotypes of a pathogen, the value of an understanding of natural variation within and among populations, and the importance of phenotype in delimiting species.

  20. Brucellosis, botflies, and brainworms: the impact of edge habitats on pathogen transmission and species extinction.

    PubMed

    Cantrell, R S; Cosner, C; Fagan, W F

    2001-02-01

    Ecological interactions between species that prefer different habitat types but come into contact in edge regions at the interfaces between habitat types are modeled via reaction-diffusion systems. The primary sort of interaction described by the models is competition mediated by pathogen transmission. The models are somewhat novel because the spatial domains for the variables describing the population densities of the interacting species overlap but do not coincide. Conditions implying coexistence of the two species or the extinction of one species are derived. The conditions involve the principal eigenvalues of elliptic operators arising from linearizations of the model system around equilibria with only one species present. The conditions for persistence or extinction are made explicit in terms of the parameters of the system and the geometry of the underlying spatial domains via estimates of the principal eigenvalues. The implications of the models with respect to conservation and refuge design are discussed.

  1. Leptospira wolffii, a potential new pathogenic Leptospira species detected in human, sheep and dog.

    PubMed

    Zakeri, Sedigheh; Khorami, Nargess; Ganji, Zahra F; Sepahian, Neda; Malmasi, Abdol-Ali; Gouya, Mohammad Mehdi; Djadid, Navid D

    2010-03-01

    Leptospirosis is the most common zoonotic disease, which is transmitted to humans through contaminated water or direct exposure to the urine of infected animals. In this study, the presence and prevalence of Leptospira species in the infected samples of human (n=369) and sheep (n=75) sera and also dogs' urine (n=150), collected from four provinces of Iran, were investigated by using nested-PCR/RFLP assay followed by sequencing analysis. Nested-PCR assay detected that 98/369 (26.5%) human, 13/75 (17.33%) of sheep's sera and 33/150 (22%) dogs' urine samples were positive for Leptospira DNA. RFLP assay detected that all positive cases had either pathogenic or intermediate Leptospira species. By sequence analysis, Leptospira interrogans was the most prevalent species among the examined samples of human (53/82, 64.6%) and sheep (11/13, 84.6%). However, in dog samples, Leptospira wolffii (27/29, 93.1%) was detected for the first time and was the dominant species. The presence of L. wolffii with 100% identity in clinical human samples and animals suspected with Leptospira may provide evidence for circulation of L. wolffii and its role in transmission cycle within human and animal hosts. In addition, this species can be potentially pathogenic to human and probably animal hosts. A large epidemiology survey would be needed to define the presence and the prevalence of this species in global endemic regions.

  2. Evaluation of two novel barcodes for species recognition of opportunistic pathogens in Fusarium.

    PubMed

    Al-Hatmi, Abdullah M S; Van Den Ende, A H G Gerrits; Stielow, J Benjamin; Van Diepeningen, Anne D; Seifert, Keith A; McCormick, Wayne; Assabgui, Rafik; Gräfenhan, Tom; De Hoog, G Sybren; Levesque, C André

    2016-02-01

    The genus Fusarium includes more than 200 species of which 73 have been isolated from human infections. Fusarium species are opportunistic human pathogens with variable aetiology. Species determination is best made with the combined phylogeny of protein-coding genes such as elongation factor (TEF1), RNA polymerase (RPB2) and the partial β-tubulin (BT2) gene. The internal transcribed spacers 1, 2 and 5.8S rRNA gene (ITS) have also been used, however, ITS cannot discriminate several closely related species and has nonorthologous copies in Fusarium. Currently, morphological approaches and tree-building methods are in use to define species and to discover hitherto undescribed species. Aftter a species is defined, DNA barcoding approaches can be used to identify species by the presence or absence of discrete nucleotide characters. We demonstrate the potential of two recently discovered DNA barcode loci, topoisomerase I (TOP1) and phosphoglycerate kinase (PGK), in combination with other routinely used markers such as TEF1, in an analysis of 144 Fusarium strains belonging to 52 species. Our barcoding study using TOP1 and PKG provided concordance of molecular data with TEF1. The currently accepted Fusarium species sampled were well supported in phylogenetic trees of both new markers.

  3. Cryptic species, native populations and biological invasions by a eucalypt forest pathogen.

    PubMed

    Pérez, Guillermo; Slippers, Bernard; Wingfield, Michael J; Wingfield, Brenda D; Carnegie, Angus J; Burgess, Treena I

    2012-09-01

    Human-associated introduction of pathogens and consequent invasions is very evident in areas where no related organisms existed before. In areas where related but distinct populations or closely related cryptic species already exist, the invasion process is much harder to unravel. In this study, the population structure of the Eucalyptus leaf pathogen Teratosphaeria nubilosa was studied within its native range in Australia, including both commercial plantations and native forests. A collection of 521 isolates from across its distribution was characterized using eight microsatellite loci, resulting in 112 multilocus haplotypes (MLHs). Multivariate and Bayesian analyses of the population conducted in structure revealed three genetically isolated groups (A, B and C), with no evidence for recombination or hybridization among groups, even when they co-occur in the same plantation. DNA sequence data of the ITS (n = 32), β-tubulin (n = 32) and 27 anonymous loci (n = 16) were consistent with microsatellite data in suggesting that T. nubilosa should be considered as a species complex. Patterns of genetic diversity provided evidence of biological invasions by the pathogen within Australia in the states of Western Australia and New South Wales and helped unravel the pattern of invasion beyond Australia into New Zealand, Brazil and Uruguay. No significant genetic differences in pathogen populations collected in native forests and commercial plantations were observed. This emphasizes the importance of sanitation in the acquisition of nursery stock for the establishment of commercial plantations.

  4. The plant pathogen Phytophthora andina emerged via hybridization of an unknown Phytophthora species and the Irish famine pathogen, P. infestans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The global movement of plant pathogens threatens natural ecosystems, food security, and commercial interests. Introduction of a plant pathogen to new geographic regions has been the primary mechanism by which new pathogens have emerged. Another documented mechanism for the emergence of plant pathoge...

  5. DNA Barcoding for Efficient Species- and Pathovar-Level Identification of the Quarantine Plant Pathogen Xanthomonas

    PubMed Central

    Tian, Qian; Zhao, Wenjun; Lu, Songyu; Zhu, Shuifang; Li, Shidong

    2016-01-01

    Genus Xanthomonas comprises many economically important plant pathogens that affect a wide range of hosts. Indeed, fourteen Xanthomonas species/pathovars have been regarded as official quarantine bacteria for imports in China. To date, however, a rapid and accurate method capable of identifying all of the quarantine species/pathovars has yet to be developed. In this study, we therefore evaluated the capacity of DNA barcoding as a digital identification method for discriminating quarantine species/pathovars of Xanthomonas. For these analyses, 327 isolates, representing 45 Xanthomonas species/pathovars, as well as five additional species/pathovars from GenBank (50 species/pathovars total), were utilized to test the efficacy of four DNA barcode candidate genes (16S rRNA gene, cpn60, gyrB, and avrBs2). Of these candidate genes, cpn60 displayed the highest rate of PCR amplification and sequencing success. The tree-building (Neighbor-joining), ‘best close match’, and barcode gap methods were subsequently employed to assess the species- and pathovar-level resolution of each gene. Notably, all isolates of each quarantine species/pathovars formed a monophyletic group in the neighbor-joining tree constructed using the cpn60 sequences. Moreover, cpn60 also demonstrated the most satisfactory results in both barcoding gap analysis and the ‘best close match’ test. Thus, compared with the other markers tested, cpn60 proved to be a powerful DNA barcode, providing a reliable and effective means for the species- and pathovar-level identification of the quarantine plant pathogen Xanthomonas. PMID:27861494

  6. Oomycete Species Associated with Soybean Seedlings in North America-Part I: Identification and Pathogenicity Characterization.

    PubMed

    Alejandro Rojas, J; Jacobs, Janette L; Napieralski, Stephanie; Karaj, Behirda; Bradley, Carl A; Chase, Thomas; Esker, Paul D; Giesler, Loren J; Jardine, Doug J; Malvick, Dean K; Markell, Samuel G; Nelson, Berlin D; Robertson, Alison E; Rupe, John C; Smith, Damon L; Sweets, Laura E; Tenuta, Albert U; Wise, Kiersten A; Chilvers, Martin I

    2017-03-01

    Oomycete pathogens are commonly associated with soybean root rot and have been estimated to reduce soybean yields in the United States by 1.5 million tons on an annual basis. Limited information exists regarding the frequency and diversity of oomycete species across the major soybean-producing regions in North America. A survey was conducted across 11 major soybean-producing states in the United States and the province of Ontario, Canada. In 2011, 2,378 oomycete cultures were isolated from soybean seedling roots on a semiselective medium (CMA-PARPB) and were identified by sequencing of the internal transcribed spacer region of rDNA. Sequence results distinguished a total of 51 Pythium spp., three Phytophthora spp., three Phytopythium spp., and one Aphanomyces sp. in 2011, with Pythium sylvaticum (16%) and P. oopapillum (13%) being the most prevalent. In 2012, the survey was repeated, but, due to drought conditions across the sampling area, fewer total isolates (n = 1,038) were collected. Additionally, in 2012, a second semiselective medium (V8-RPBH) was included, which increased the Phytophthora spp. isolated from 0.7 to 7% of the total isolates. In 2012, 54 Pythium spp., seven Phytophthora spp., six Phytopythium spp., and one Pythiogeton sp. were recovered, with P. sylvaticum (14%) and P. heterothallicum (12%) being recovered most frequently. Pathogenicity and virulence were evaluated with representative isolates of each of the 84 species on soybean cv. Sloan. A seed-rot assay identified 13 and 11 pathogenic species, respectively, at 13 and 20°C. A seedling-root assay conducted at 20°C identified 43 species as pathogenic, having a significantly detrimental effect on the seedling roots as compared with the noninoculated control. A total of 15 species were pathogenic in both the seed and seedling assays. This study provides a comprehensive characterization of oomycete species present in soybean seedling roots in the major production areas in the United States and

  7. Multiplex characterization of human pathogens including species and antibiotic-resistance gene identification.

    PubMed

    Barisˇ ić, Ivan; Petzka, Josefine; Schoenthaler, Silvia; Vierlinger, Klemens; Noehammer, Christa; Wiesinger-Mayr, Herbert

    2016-01-01

    The efficient medical treatment of infections requires detailed information about the pathogens involved and potential antibiotic-resistance mechanisms. The dramatically increasing incidence of multidrug-resistant bacteria especially highlights the importance of sophisticated diagnostic tests enabling a fast patient-customized therapy. However, the current molecular detection methods are limited to either the detection of species or only a few antibiotic-resistance genes.In this work, we present a human pathogen characterization assay using a rRNA gene microarray identifying 75 species comprising bacteria and fungi. A statistical classifier was developed to facilitate the automated species identification. Additionally, the clinically most important β-lactamases were identified simultaneously in a 100-plex reaction using padlock probes and the same microarray. The specificity and sensitivity of the combined assay was determined using clinical isolates. The detection limit was 10(5) c.f.u. ml(-1), recovering 89 % of the detectable β-lactamase-encoding genes specifically. The total assay time was less than 7 hand the modular character of the antibiotic-resistance detection allows the easy integration of further genetic targets. In summary, we present a fast, highly specific and sensitive multiplex pathogen characterization assay.

  8. Multiple Origins of the Pathogenic Yeast Candida orthopsilosis by Separate Hybridizations between Two Parental Species

    PubMed Central

    Hammel, Stephen; Higgins, Desmond G.; Bagagli, Eduardo

    2016-01-01

    Mating between different species produces hybrids that are usually asexual and stuck as diploids, but can also lead to the formation of new species. Here, we report the genome sequences of 27 isolates of the pathogenic yeast Candida orthopsilosis. We find that most isolates are diploid hybrids, products of mating between two unknown parental species (A and B) that are 5% divergent in sequence. Isolates vary greatly in the extent of homogenization between A and B, making their genomes a mosaic of highly heterozygous regions interspersed with homozygous regions. Separate phylogenetic analyses of SNPs in the A- and B-derived portions of the genome produces almost identical trees of the isolates with four major clades. However, the presence of two mutually exclusive genotype combinations at the mating type locus, and recombinant mitochondrial genomes diagnostic of inter-clade mating, shows that the species C. orthopsilosis does not have a single evolutionary origin but was created at least four times by separate interspecies hybridizations between parents A and B. Older hybrids have lost more heterozygosity. We also identify two isolates with homozygous genomes derived exclusively from parent A, which are pure non-hybrid strains. The parallel emergence of the same hybrid species from multiple independent hybridization events is common in plant evolution, but is much less documented in pathogenic fungi. PMID:27806045

  9. The Colletotrichum destructivum species complex – hemibiotrophic pathogens of forage and field crops

    PubMed Central

    Damm, U.; O'Connell, R.J.; Groenewald, J.Z.; Crous, P.W.

    2014-01-01

    Colletotrichum destructivum is an important plant pathogen, mainly of forage and grain legumes including clover, alfalfa, cowpea and lentil, but has also been reported as an anthracnose pathogen of many other plants worldwide. Several Colletotrichum isolates, previously reported as closely related to C. destructivum, are known to establish hemibiotrophic infections in different hosts. The inconsistent application of names to those isolates based on outdated species concepts has caused much taxonomic confusion, particularly in the plant pathology literature. A multilocus DNA sequence analysis (ITS, GAPDH, CHS-1, HIS3, ACT, TUB2) of 83 isolates of C. destructivum and related species revealed 16 clades that are recognised as separate species in the C. destructivum complex, which includes C. destructivum, C. fuscum, C. higginsianum, C. lini and C. tabacum. Each of these species is lecto-, epi- or neotypified in this study. Additionally, eight species, namely C. americae-borealis, C. antirrhinicola, C. bryoniicola, C. lentis, C. ocimi, C. pisicola, C. utrechtense and C. vignae are newly described. PMID:25492986

  10. Metabolomics Analysis Reveals Specific Novel Tetrapeptide and Potential Anti-Inflammatory Metabolites in Pathogenic Aspergillus species

    PubMed Central

    Lee, Kim-Chung; Tam, Emily W. T.; Lo, Ka-Ching; Tsang, Alan K. L.; Lau, Candy C. Y.; To, Kelvin K. W.; Chan, Jasper F. W.; Lam, Ching-Wan; Yuen, Kwok-Yung; Lau, Susanna K. P.; Woo, Patrick C. Y.

    2015-01-01

    Infections related to Aspergillus species have emerged to become an important focus in infectious diseases, as a result of the increasing use of immunosuppressive agents and high fatality associated with invasive aspergillosis. However, laboratory diagnosis of Aspergillus infections remains difficult. In this study, by comparing the metabolomic profiles of the culture supernatants of 30 strains of six pathogenic Aspergillus species (A. fumigatus, A. flavus, A. niger, A. terreus, A. nomius and A. tamarii) and 31 strains of 10 non-Aspergillus fungi, eight compounds present in all strains of the six Aspergillus species but not in any strain of the non-Aspergillus fungi were observed. One of the eight compounds, Leu–Glu–Leu–Glu, is a novel tetrapeptide and represents the first linear tetrapeptide observed in Aspergillus species, which we propose to be named aspergitide. Two other closely related Aspergillus-specific compounds, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid, may possess anti-inflammatory properties, as 2-(sulfooxy)benzoic acid possesses a structure similar to those of aspirin [2-(acetoxy)benzoic acid] and salicylic acid (2-hydroxybenzoic acid). Further studies to examine the potentials of these Aspergillus-specific compounds for laboratory diagnosis of aspergillosis are warranted and further experiments will reveal whether Leu–Glu–Leu–Glu, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid are virulent factors of the pathogenic Aspergillus species. PMID:26090713

  11. Draft Genome Sequences of Two Pathogenic Corynebacterial Species Isolated from Cows

    PubMed Central

    Guimarães, Luis Carlos; Lopes, Thiago; Ramos, Rommel Thiago Jucá; Carneiro, Adriana Ribeiro; Cavalcante, Ana Lídia Queiroz; Barreto, Diego; de Sá, Pablo Caracciolo Gomes; Veras, Adonney Allan Oliveira; Rocha, Flávia Souza; Bagano, Priscilla; Pereira, Felipe Luiz; Dorella, Fernanda Alves; Leal, Carlos Augusto; Carvalho, Alex Fiorini; Bizet, Chantal; Guiso, Nicole; Badell, Edgar; Figueiredo, Henrique César Pereira; Azevedo, Vasco; Silva, Artur

    2016-01-01

    The species Corynebacterium renale, Corynebacterium pilosum, and Corynebacterium cystitidis were initially thought to be the same species C. renale, but with different immunological types. These bacteria are the causative agent of cystitis, urethritis and pyelonephritis and are found usually as constituents of the normal flora in the lower urogenital tract of cattle. Therefore, we present the draft genome sequences of two pathogenic Corynebacterium species: C. renale CIP 52.96 and C. pilosum CIP 103422. The genome sequences of these species have 2,322,762 bp with 2,218 protein encoding genes and 2,548,014 bp with 2,428 protein encoding genes, respectively. These genomes can help clarify the virulence mechanisms of these unknown bacteria and enable the development of more effective methods for control. PMID:26958092

  12. Virulence of oomycete pathogens from Phragmites australis-invaded and noninvaded soils to seedlings of wetland plant species.

    PubMed

    Crocker, Ellen V; Karp, Mary Ann; Nelson, Eric B

    2015-06-01

    Soil pathogens affect plant community structure and function through negative plant-soil feedbacks that may contribute to the invasiveness of non-native plant species. Our understanding of these pathogen-induced soil feedbacks has relied largely on observations of the collective impact of the soil biota on plant populations, with few observations of accompanying changes in populations of specific soil pathogens and their impacts on invasive and noninvasive species. As a result, the roles of specific soil pathogens in plant invasions remain unknown. In this study, we examine the diversity and virulence of soil oomycete pathogens in freshwater wetland soils invaded by non-native Phragmites australis (European common reed) to better understand the potential for soil pathogen communities to impact a range of native and non-native species and influence invasiveness. We isolated oomycetes from four sites over a 2-year period, collecting nearly 500 isolates belonging to 36 different species. These sites were dominated by species of Pythium, many of which decreased seedling survival of a range of native and invasive plants. Despite any clear host specialization, many of the Pythium species were differentially virulent to the native and non-native plant species tested. Isolates from invaded and noninvaded soils were equally virulent to given individual plant species, and no apparent differences in susceptibility were observed between the collective groups of native and non-native plant species.

  13. Genomes of three tomato pathogens within the Ralstonia solanacearum species complex reveal significant evolutionary divergence

    PubMed Central

    2010-01-01

    Background The Ralstonia solanacearum species complex includes thousands of strains pathogenic to an unusually wide range of plant species. These globally dispersed and heterogeneous strains cause bacterial wilt diseases, which have major socio-economic impacts. Pathogenicity is an ancestral trait in R. solanacearum and strains with high genetic variation can be subdivided into four phylotypes, correlating to isolates from Asia (phylotype I), the Americas (phylotype IIA and IIB), Africa (phylotype III) and Indonesia (phylotype IV). Comparison of genome sequences strains representative of this phylogenetic diversity can help determine which traits allow this bacterium to be such a pathogen of so many different plant species and how the bacteria survive in many different habitats. Results The genomes of three tomato bacterial wilt pathogens, CFBP2957 (phy. IIA), CMR15 (phy. III) and PSI07 (phy. IV) were sequenced and manually annotated. These genomes were compared with those of three previously sequenced R. solanacearum strains: GMI1000 (tomato, phy. I), IPO1609 (potato, phy. IIB), and Molk2 (banana, phy. IIB). The major genomic features (size, G+C content, number of genes) were conserved across all of the six sequenced strains. Despite relatively high genetic distances (calculated from average nucleotide identity) and many genomic rearrangements, more than 60% of the genes of the megaplasmid and 70% of those on the chromosome are syntenic. The three new genomic sequences revealed the presence of several previously unknown traits, probably acquired by horizontal transfers, within the genomes of R. solanacearum, including a type IV secretion system, a rhi-type anti-mitotic toxin and two small plasmids. Genes involved in virulence appear to be evolving at a faster rate than the genome as a whole. Conclusions Comparative analysis of genome sequences and gene content confirmed the differentiation of R. solanacearum species complex strains into four phylotypes. Genetic

  14. Molecular characterization of pathogenic Fusarium species in cucurbit plants from Kermanshah province, Iran

    PubMed Central

    Chehri, K.; Salleh, B.; Yli-Mattila, T.; Reddy, K.R.N.; Abbasi, S.

    2011-01-01

    Fusarium is one of the important phytopathogenic genera of microfungi causing serious losses on cucurbit plants in Kermanshah province, the largest area of cucurbits plantation in Iran. Therefore, the objectives in this study were to isolate and identify disease-causing Fusarium spp. from infected cucurbit plants, to ascertain their pathogenicity, and to determine their phylogenetic relationships. A total of 100 Fusarium isolates were obtained from diseased cucurbit plants collected from fields in different geographic regions in Kermanshah province, Iran. According to morphological characters, all isolates were identified as Fusarium oxysporum, Fusarium proliferatum, Fusarium equiseti, Fusarium semitectum and Fusarium solani. All isolates of the five Fusarium spp. were evaluated for their pathogenicity on healthy cucumber (Cucumis sativus) and honeydew melon (Cucumis melo) seedlings in the glasshouse. F. oxysporum caused damping-off in 20–35 days on both cucurbit seedlings tested. Typical stem rot symptoms were observed within 15 days after inoculation with F. solani on both seedlings. Based on the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA) restriction fragment length polymorphism (RFLP) analysis, the five Fusarium species were divided into two major groups. In particular, isolates belonging to the F. solani species complex (FSSC) were separated into two RFLP types. Grouping among Fusarium strains derived from restriction analysis was in agreement with criteria used in morphological classification. Therefore, the PCR-ITS-RFLP method provides a simple and rapid procedure for the differentiation of Fusarium strains at species level. This is the first report on identification and pathogenicity of major plant pathogenic Fusarium spp. causing root and stem rot on cucurbits in Iran. PMID:23961146

  15. Phylogeny and Phenotypic Characterization of Pathogenic Cryptococcus Species and Closely Related Saprobic Taxa in the Tremellales ▿ †

    PubMed Central

    Findley, Keisha; Rodriguez-Carres, Marianela; Metin, Banu; Kroiss, Johannes; Fonseca, Álvaro; Vilgalys, Rytas; Heitman, Joseph

    2009-01-01

    The basidiomycetous yeasts Cryptococcus neoformans and Cryptococcus gattii are closely related sibling species that cause respiratory and neurological disease in humans and animals. Within these two recognized species, phylogenetic analysis reveals at least six cryptic species defined as molecular types (VNI/II/B, VNIV, VGI, VGII, VGIII, and VGIV) that comprise the pathogenic Cryptococcus species complex. These pathogenic species are clustered in the Filobasidiella clade within the order Tremellales. Previous studies have shown that the Filobasidiella clade also includes several saprobic fungi isolated from insect frass, but information evaluating the relatedness of the saprobes and pathogens within this cluster is limited. Here, the phylogeny encompassing a subset of species in the Tremellales lineage that clusters closely with the pathogenic Cryptococcus species complex was resolved by employing a multilocus sequencing approach for phylogenetic analysis. Six highly conserved genomic loci from 15 related basidiomycete species were sequenced, and the alignments from the concatenated gene sequences were evaluated with different tree-building criteria. Furthermore, these 15 species were subjected to virulence and phenotype assays to evaluate their pathogenic potential. These studies revealed that Cryptococcus amylolentus and Tsuchiyaea wingfieldii, two nonpathogenic sibling species, are the taxa most closely related to the pathogens C. neoformans and C. gattii and together with Filobasidiella depauperata form a Cryptococcus sensu stricto group. Five other saprobic yeast species form the Kwoniella clade, which appears to be a part of a more distantly related sensu lato group. This study establishes a foundation for future comparative genomic approaches that will provide insight into the structure, function, and evolution of the mating type locus, the transitions in modes of sexual reproduction, and the emergence of human pathogenic species from related or ancestral

  16. A Natural Mutation Involving both Pathogenicity and Perithecium Formation in the Fusarium graminearum Species Complex

    PubMed Central

    Suga, Haruhisha; Kageyama, Koji; Shimizu, Masafumi; Hyakumachi, Misturo

    2016-01-01

    Members of the Fusarium graminearum species complex (Fg complex or FGSC) are the primary pathogens causing Fusarium head blight in wheat and barley worldwide. A natural pathogenicity mutant (strain 0225022) was found in a sample of the Fg complex collected in Japan. The mutant strain did not induce symptoms in wheat spikes beyond the point of inoculation, and did not form perithecia. No segregation of phenotypic deficiencies occurred in the progenies of a cross between the mutant and a fully pathogenic wild-type strain, which suggested that a single genetic locus controlled both traits. The locus was mapped to chromosome 2 by using sequence-tagged markers; and a deletion of ∼3 kb was detected in the mapped region of the mutant strain. The wild-type strain contains the FGSG_02810 gene, encoding a putative glycosylphosphatidylinositol anchor protein, in this region. The contribution of FGSG_02810 to pathogenicity and perithecium formation was confirmed by complementation in the mutant strain using gene transfer, and by gene disruption in the wild-type strain. PMID:27678518

  17. Species tree estimation for the late blight pathogen, Phytophthora infestans, and close relatives.

    PubMed

    Blair, Jaime E; Coffey, Michael D; Martin, Frank N

    2012-01-01

    To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary processes. Discordances among gene trees and between the gene trees and the species tree are also expected in closely related species that have rapidly diverged, due to processes such as the incomplete sorting of ancestral polymorphisms. Recently, methods have been developed for the explicit estimation of species trees, using information from multilocus gene trees while accommodating heterogeneity among them. Here we have used three distinct approaches to estimate the species tree for five Phytophthora pathogens, including P. infestans, the causal agent of late blight disease in potato and tomato. Our concatenation-based "supergene" approach was unable to resolve relationships even with data from both the nuclear and mitochondrial genomes, and from multiple isolates per species. Our multispecies coalescent approach using both Bayesian and maximum likelihood methods was able to estimate a moderately supported species tree showing a close relationship among P. infestans, P. andina, and P. ipomoeae. The topology of the species tree was also identical to the dominant phylogenetic history estimated in our third approach, Bayesian concordance analysis. Our results support previous suggestions that P. andina is a hybrid species, with P. infestans representing one parental lineage. The other parental lineage is not known, but represents an independent evolutionary lineage more closely related to P. ipomoeae. While all five species likely originated in the New World, further study is needed to determine when and under what conditions this hybridization event may have occurred.

  18. Species Tree Estimation for the Late Blight Pathogen, Phytophthora infestans, and Close Relatives

    PubMed Central

    Blair, Jaime E.; Coffey, Michael D.; Martin, Frank N.

    2012-01-01

    To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary processes. Discordances among gene trees and between the gene trees and the species tree are also expected in closely related species that have rapidly diverged, due to processes such as the incomplete sorting of ancestral polymorphisms. Recently, methods have been developed for the explicit estimation of species trees, using information from multilocus gene trees while accommodating heterogeneity among them. Here we have used three distinct approaches to estimate the species tree for five Phytophthora pathogens, including P. infestans, the causal agent of late blight disease in potato and tomato. Our concatenation-based “supergene” approach was unable to resolve relationships even with data from both the nuclear and mitochondrial genomes, and from multiple isolates per species. Our multispecies coalescent approach using both Bayesian and maximum likelihood methods was able to estimate a moderately supported species tree showing a close relationship among P. infestans, P. andina, and P. ipomoeae. The topology of the species tree was also identical to the dominant phylogenetic history estimated in our third approach, Bayesian concordance analysis. Our results support previous suggestions that P. andina is a hybrid species, with P. infestans representing one parental lineage. The other parental lineage is not known, but represents an independent evolutionary lineage more closely related to P. ipomoeae. While all five species likely originated in the New World, further study is needed to determine when and under what conditions this hybridization event may have occurred. PMID:22615869

  19. Intra- and inter-species interactions within biofilms of important foodborne bacterial pathogens

    PubMed Central

    Giaouris, Efstathios; Heir, Even; Desvaux, Mickaël; Hébraud, Michel; Møretrø, Trond; Langsrud, Solveig; Doulgeraki, Agapi; Nychas, George-John; Kačániová, Miroslava; Czaczyk, Katarzyna; Ölmez, Hülya; Simões, Manuel

    2015-01-01

    A community-based sessile life style is the normal mode of growth and survival for many bacterial species. Under such conditions, cell-to-cell interactions are inevitable and ultimately lead to the establishment of dense, complex and highly structured biofilm populations encapsulated in a self-produced extracellular matrix and capable of coordinated and collective behavior. Remarkably, in food processing environments, a variety of different bacteria may attach to surfaces, survive, grow, and form biofilms. Salmonella enterica, Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus are important bacterial pathogens commonly implicated in outbreaks of foodborne diseases, while all are known to be able to create biofilms on both abiotic and biotic surfaces. Particularly challenging is the attempt to understand the complexity of inter-bacterial interactions that can be encountered in such unwanted consortia, such as competitive and cooperative ones, together with their impact on the final outcome of these communities (e.g., maturation, physiology, antimicrobial resistance, virulence, dispersal). In this review, up-to-date data on both the intra- and inter-species interactions encountered in biofilms of these pathogens are presented. A better understanding of these interactions, both at molecular and biophysical levels, could lead to novel intervention strategies for controlling pathogenic biofilm formation in food processing environments and thus improve food safety. PMID:26347727

  20. Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex

    PubMed Central

    Rodriguez-Carres, Marianela; Findley, Keisha; Sun, Sheng; Dietrich, Fred S.; Heitman, Joseph

    2010-01-01

    The fungal species Cryptococcus neoformans and Cryptococcus gattii cause respiratory and neurological disease in animals and humans following inhalation of basidiospores or desiccated yeast cells from the environment. Sexual reproduction in C. neoformans and C. gattii is controlled by a bipolar system in which a single mating type locus (MAT) specifies compatibility. These two species are dimorphic, growing as yeast in the asexual stage, and producing hyphae, basidia, and basidiospores during the sexual stage. In contrast, Filobasidiella depauperata, one of the closest related species, grows exclusively as hyphae and it is found in association with decaying insects. Examination of two available strains of F. depauperata showed that the life cycle of this fungal species shares features associated with the unisexual or same-sex mating cycle in C. neoformans. Therefore, F. depauperata may represent a homothallic and possibly an obligately sexual fungal species. RAPD genotyping of 39 randomly isolated progeny from isolate CBS7855 revealed a new genotype pattern in one of the isolated basidiospores progeny, therefore suggesting that the homothallic cycle in F. depauperata could lead to the emergence of new genotypes. Phylogenetic analyses of genes linked to MAT in C. neoformans indicated that two of these genes in F. depauperata, MYO2 and STE20, appear to form a monophyletic clade with the MATa alleles of C. neoformans and C. gattii, and thus these genes may have been recruited to the MAT locus before F. depauperata diverged. Furthermore, the ancestral MATa locus may have undergone accelerated evolution prior to the divergence of the pathogenic Cryptococcus species since several of the genes linked to the MATa locus appear to have a higher number of changes and substitutions than their MATα counterparts. Synteny analyses between C. neoformans and F. depauperata showed that genomic regions on other chromosomes displayed conserved gene order. In contrast, the genes

  1. The plant pathogen Phytophthora andina emerged via hybridization of an unknown Phytophthora species and the Irish potato famine pathogen, P. infestans.

    PubMed

    Goss, Erica M; Cardenas, Martha E; Myers, Kevin; Forbes, Gregory A; Fry, William E; Restrepo, Silvia; Grünwald, Niklaus J

    2011-01-01

    Emerging plant pathogens have largely been a consequence of the movement of pathogens to new geographic regions. Another documented mechanism for the emergence of plant pathogens is hybridization between individuals of different species or subspecies, which may allow rapid evolution and adaptation to new hosts or environments. Hybrid plant pathogens have traditionally been difficult to detect or confirm, but the increasing ease of cloning and sequencing PCR products now makes the identification of species that consistently have genes or alleles with phylogenetically divergent origins relatively straightforward. We investigated the genetic origin of Phytophthora andina, an increasingly common pathogen of Andean crops Solanum betaceum, S. muricatum, S. quitoense, and several wild Solanum spp. It has been hypothesized that P. andina is a hybrid between the potato late blight pathogen P. infestans and another Phytophthora species. We tested this hypothesis by cloning four nuclear loci to obtain haplotypes and using these loci to infer the phylogenetic relationships of P. andina to P. infestans and other related species. Sequencing of cloned PCR products in every case revealed two distinct haplotypes for each locus in P. andina, such that each isolate had one allele derived from a P. infestans parent and a second divergent allele derived from an unknown species that is closely related but distinct from P. infestans, P. mirabilis, and P. ipomoeae. To the best of our knowledge, the unknown parent has not yet been collected. We also observed sequence polymorphism among P. andina isolates at three of the four loci, many of which segregate between previously described P. andina clonal lineages. These results provide strong support that P. andina emerged via hybridization between P. infestans and another unknown Phytophthora species also belonging to Phytophthora clade 1c.

  2. Tree diversity and the role of non-host neighbour tree species in reducing fungal pathogen infestation.

    PubMed

    Hantsch, Lydia; Bien, Steffen; Radatz, Stine; Braun, Uwe; Auge, Harald; Bruelheide, Helge

    2014-11-01

    The degree to which plant pathogen infestation occurs in a host plant is expected to be strongly influenced by the level of species diversity among neighbouring host and non-host plant species. Since pathogen infestation can negatively affect host plant performance, it can mediate the effects of local biodiversity on ecosystem functioning.We tested the effects of tree diversity and the proportion of neighbouring host and non-host species with respect to the foliar fungal pathogens of Tilia cordata and Quercus petraea in the Kreinitz tree diversity experiment in Germany. We hypothesized that fungal pathogen richness increases while infestation decreases with increasing local tree diversity. In addition, we tested whether fungal pathogen richness and infestation are dependent on the proportion of host plant species present or on the proportion of particular non-host neighbouring tree species.Leaves of the two target species were sampled across three consecutive years with visible foliar fungal pathogens on the leaf surface being identified macro- and microscopically. Effects of diversity among neighbouring trees were analysed: (i) for total fungal species richness and fungal infestation on host trees and (ii) for infestation by individual fungal species.We detected four and five fungal species on T. cordata and Q. petraea, respectively. High local tree diversity reduced (i) total fungal species richness and infestation of T. cordata and fungal infestation of Q. petraea and (ii) infestation by three host-specialized fungal pathogen species. These effects were brought about by local tree diversity and were independent of host species proportion. In general, host species proportion had almost no effect on fungal species richness and infestation. Strong effects associated with the proportion of particular non-host neighbouring tree species on fungal species richness and infestation were, however, recorded.Synthesis. For the first time, we experimentally demonstrated

  3. Tree diversity and the role of non-host neighbour tree species in reducing fungal pathogen infestation

    PubMed Central

    Hantsch, Lydia; Bien, Steffen; Radatz, Stine; Braun, Uwe; Auge, Harald; Bruelheide, Helge

    2014-01-01

    The degree to which plant pathogen infestation occurs in a host plant is expected to be strongly influenced by the level of species diversity among neighbouring host and non-host plant species. Since pathogen infestation can negatively affect host plant performance, it can mediate the effects of local biodiversity on ecosystem functioning. We tested the effects of tree diversity and the proportion of neighbouring host and non-host species with respect to the foliar fungal pathogens of Tilia cordata and Quercus petraea in the Kreinitz tree diversity experiment in Germany. We hypothesized that fungal pathogen richness increases while infestation decreases with increasing local tree diversity. In addition, we tested whether fungal pathogen richness and infestation are dependent on the proportion of host plant species present or on the proportion of particular non-host neighbouring tree species. Leaves of the two target species were sampled across three consecutive years with visible foliar fungal pathogens on the leaf surface being identified macro- and microscopically. Effects of diversity among neighbouring trees were analysed: (i) for total fungal species richness and fungal infestation on host trees and (ii) for infestation by individual fungal species. We detected four and five fungal species on T. cordata and Q. petraea, respectively. High local tree diversity reduced (i) total fungal species richness and infestation of T. cordata and fungal infestation of Q. petraea and (ii) infestation by three host-specialized fungal pathogen species. These effects were brought about by local tree diversity and were independent of host species proportion. In general, host species proportion had almost no effect on fungal species richness and infestation. Strong effects associated with the proportion of particular non-host neighbouring tree species on fungal species richness and infestation were, however, recorded. Synthesis. For the first time, we experimentally

  4. Staphylococcal response to oxidative stress

    PubMed Central

    Gaupp, Rosmarie; Ledala, Nagender; Somerville, Greg A.

    2012-01-01

    Staphylococci are a versatile genus of bacteria that are capable of causing acute and chronic infections in diverse host species. The success of staphylococci as pathogens is due in part to their ability to mitigate endogenous and exogenous oxidative and nitrosative stress. Endogenous oxidative stress is a consequence of life in an aerobic environment; whereas, exogenous oxidative and nitrosative stress are often due to the bacteria's interaction with host immune systems. To overcome the deleterious effects of oxidative and nitrosative stress, staphylococci have evolved protection, detoxification, and repair mechanisms that are controlled by a network of regulators. In this review, we summarize the cellular targets of oxidative stress, the mechanisms by which staphylococci sense oxidative stress and damage, oxidative stress protection and repair mechanisms, and regulation of the oxidative stress response. When possible, special attention is given to how the oxidative stress defense mechanisms help staphylococci control oxidative stress in the host. PMID:22919625

  5. Multiple Pathogens Including Potential New Species in Tick Vectors in Côte d’Ivoire

    PubMed Central

    Ehounoud, Cyrille Bilé; Yao, Kouassi Patrick; Dahmani, Mustapha; Achi, Yaba Louise; Amanzougaghene, Nadia; Kacou N’Douba, Adèle; N’Guessan, Jean David; Raoult, Didier; Fenollar, Florence; Mediannikov, Oleg

    2016-01-01

    Background Our study aimed to assess the presence of different pathogens in ticks collected in two regions in Côte d’Ivoire. Methodology/Principal Findings Real-time PCR and standard PCR assays coupled to sequencing were used. Three hundred and seventy eight (378) ticks (170 Amblyomma variegatum, 161 Rhipicepalus microplus, 3 Rhipicephalus senegalensis, 27 Hyalomma truncatum, 16 Hyalomma marginatum rufipes, and 1 Hyalomma impressum) were identified and analyzed. We identified as pathogenic bacteria, Rickettsia africae in Am. variegatum (90%), Rh. microplus (10%) and Hyalomma spp. (9%), Rickettsia aeschlimannii in Hyalomma spp. (23%), Rickettsia massiliae in Rh. senegalensis (33%) as well as Coxiella burnetii in 0.2%, Borrelia sp. in 0.2%, Anaplasma centrale in 0.2%, Anaplasma marginale in 0.5%, and Ehrlichia ruminantium in 0.5% of all ticks. Potential new species of Borrelia, Anaplasma, and Wolbachia were detected. Candidatus Borrelia africana and Candidatus Borrelia ivorensis (detected in three ticks) are phylogenetically distant from both the relapsing fever group and Lyme disease group borreliae; both were detected in Am. variegatum. Four new genotypes of bacteria from the Anaplasmataceae family were identified, namely Candidatus Anaplasma ivorensis (detected in three ticks), Candidatus Ehrlichia urmitei (in nine ticks), Candidatus Ehrlichia rustica (in four ticks), and Candidatus Wolbachia ivorensis (in one tick). Conclusions/Significance For the first time, we demonstrate the presence of different pathogens such as R. aeschlimannii, C. burnetii, Borrelia sp., A. centrale, A. marginale, and E. ruminantium in ticks in Côte d’Ivoire as well as potential new species of unknown pathogenicity. PMID:26771308

  6. Synergistic fungicidal activity of the lipopeptide bacillomycin D with amphotericin B against pathogenic Candida species.

    PubMed

    Tabbene, Olfa; Di Grazia, Antonio; Azaiez, Sana; Ben Slimene, Imen; Elkahoui, Salem; Alfeddy, Mohamed Najib; Casciaro, Bruno; Luca, Vincenzo; Limam, Ferid; Mangoni, Maria Luisa

    2015-06-01

    In the present study, the synergism of the lipopeptide bacillomycin D in combination with the polyene amphotericin B against pathogenic Candida species is described along with their potential cytotoxicity against mammalian cells. Bacillomycin D inhibited the growth of various Candida species at minimal concentrations from 12.5 to 25 μg ml(-1). Furthermore, it showed a synergistic effect with the antifungal drug amphotericin B in inhibiting the growth of Candida strains, with fractional inhibitory concentration indices ranging from 0.28 to 0.5. Time killing studies revealed a >2-log reduction in the viability of Candida albicans ATCC 10231 cells after 3 h incubation with the combination amphotericin B plus bacillomycin D, at their subinhibitory concentration. Interestingly, when the two drugs were used together at those dosages displaying a synergism in the anti-Candida activity, no cytotoxic effect was observed against mammalian cells. Therefore, the combination bacillomycin D/amphotericin B may represent a valid alternative to conventional antifungals for topical treatment of C. albicans infections. To the best of our knowledge, this is the first report describing the in vitro interaction between the antifungal drug amphotericin B and bacillomycin D against pathogenic Candida species.

  7. Proteomic analysis of cell wall in four pathogenic species of Candida exposed to oxidative stress.

    PubMed

    Ramírez-Quijas, Mayra Denisse; López-Romero, Everardo; Cuéllar-Cruz, Mayra

    2015-10-01

    In order for Candida species to adhere and colonize human host cells they must express cell wall proteins (CWP) and adapt to reactive oxygen species (ROS) generated by phagocytic cells of the human host during the respiratory burst. However, how these pathogens change the expression of CWP in response to oxidative stress (OSR) is not known. Here, fifteen moonlight-like CWP were identified that expressed differentially in four species of Candida after they were exposed to H2O2 or menadione (O2(-)). These proteins included: (i) glycolytic enzymes, such as glyceraldehyde-3-phosphate dehydrogenase (Gapdh), fructose-bisphosphate aldolase (Fba1), phosphoglycerate mutase (Gpm1), phosphoglycerate kinase (Pgk), pyruvate kinase (Pk) and enolase (Eno1); (ii) the heat shock proteins Ssb1 and Ssa2; (iii) OSR proteins such as peroxyredoxin (Tsa1), the stress protein Ddr48 (Ddr48) and glutathione reductase (Glr1); (iv) other metabolic enzymes such as ketol-acid reductoisomerase (Ilv5) and pyruvate decarboxylase (Pdc1); and (v) other proteins such as elongation factor 1-beta (Efb1) and the 14-3-3 protein homolog. RT-PCR revealed that transcription of the genes coding for some of the identified CWP are differentially regulated. To our knowledge this is the first report showing that moonlight-like CWP are the first line of defense of Candida against ROS, and that they are differentially regulated in each of these pathogens.

  8. Hybridization of powdery mildew strains gives rise to pathogens on novel agricultural crop species.

    PubMed

    Menardo, Fabrizio; Praz, Coraline R; Wyder, Stefan; Ben-David, Roi; Bourras, Salim; Matsumae, Hiromi; McNally, Kaitlin E; Parlange, Francis; Riba, Andrea; Roffler, Stefan; Schaefer, Luisa K; Shimizu, Kentaro K; Valenti, Luca; Zbinden, Helen; Wicker, Thomas; Keller, Beat

    2016-02-01

    Throughout the history of agriculture, many new crop species (polyploids or artificial hybrids) have been introduced to diversify products or to increase yield. However, little is known about how these new crops influence the evolution of new pathogens and diseases. Triticale is an artificial hybrid of wheat and rye, and it was resistant to the fungal pathogen powdery mildew (Blumeria graminis) until 2001 (refs. 1,2,3). We sequenced and compared the genomes of 46 powdery mildew isolates covering several formae speciales. We found that B. graminis f. sp. triticale, which grows on triticale and wheat, is a hybrid between wheat powdery mildew (B. graminis f. sp. tritici) and mildew specialized on rye (B. graminis f. sp. secalis). Our data show that the hybrid of the two mildews specialized on two different hosts can infect the hybrid plant species originating from those two hosts. We conclude that hybridization between mildews specialized on different species is a mechanism of adaptation to new crops introduced by agriculture.

  9. Phylogenetic, Morphological, and Pathogenic Characterization of Alternaria Species Associated with Fruit Rot of Blueberry in California.

    PubMed

    Zhu, X Q; Xiao, C L

    2015-12-01

    Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruit. The aims of this study were to characterize Alternaria isolates using morphological and molecular approaches and test their pathogenicity to blueberry fruit. Alternaria spp. isolates were collected from decayed blueberry fruit in the Central Valley of California during 2012 and 2013. In total, 283 isolates were obtained and five species of Alternaria, including Alternaria alternata, A. tenuissima, A. arborescens, A. infectoria, and A. rosae, were identified based on DNA sequences of the plasma membrane ATPase, Alt a1 and Calmodulin gene regions in combination with morphological characters of the culture and sporulation. Of the 283 isolates, 61.5% were identified as A. alternata, 32.9% were A. arborescens, 5.0% were A. tenuissima, and only one isolate of A. infectoria and one isolate of A. rosae were found. These fungi were able to grow at temperatures from 0 to 35°C, and mycelial growth was arrested at 40°C. Optimal radial growth occurred between 20 to 30°C. Pathogenicity tests showed that all five Alternaria spp. were pathogenic on blueberry fruit at 0, 4, and 20°C, with A. alternata, A. arborescens, and A. tenuissima being the most virulent species, followed by A. infectoria and A. rosae. Previously A. tenuissima has been reported to be the primary cause of Alternaria fruit rot of blueberry worldwide. Our results indicated that the species composition of Alternaria responsible for Alternaria fruit rot in blueberry can be dependent on geographical region. A. alternata, A. arborescens, A. infectoria, and A. rosae are reported for the first time on blueberry in California. This is also the first report of A. infectoria and A. rosae infecting blueberry fruit.

  10. Microbial conversion of tomato by a plant pathogenic bacterium Pectobacterium atrosepticum: a plant-microbial approach to control pathogenic Candida species.

    PubMed

    Bajpai, Vivek K; Kang, Sun Chul; Lee, Soon-Gu; Baek, Kwang-Hyun

    2012-01-01

    This study was carried out to produce bioconverted products by microbial fermentation of tomato using a plant pathogenic bacterium Pectobacterium atrosepticum and to evaluate their in vitro antimycotic effect against pathogenic Candida species. The bioconverted products (500 microg/disc) provoked promising antimycotic effects against pathogenic isolates of Candida species as shown by the diameters of zones of inhibition (9 +/- 0.6 to 14 +/- 0.4 mm), along with their respective minimum inhibitory and minimum fungicidal concentration values, which increased from 250 to 1000 and 250 to 2000 microg/mL, respectively. With the viable counts of the tested fungal pathogens, exposure of the bioconverted products revealed a remarkable antimycotic effect. In addition, the morphology of a clinical isolate of C. glabrata KBN06P00368, visualized by scanning electron microscopy, showed a severe detrimental effect produced by the bioconverted products at the minimum inhibitory concentration (250 microg/mL). The bioconverted products significantly inhibited the in vitro growth of all the tested clinical and pathogenic laboratory isolates of Candida species. This study confirmed the potent antimycotic efficacy of the bioconverted products of tomato, hence justifying the therapeutic uses of bioconverted products in pharmaceutical preparations as an alternative approach to support the antifungal activity of conventional antimycotics.

  11. The Janus face of reactive oxygen species in resistance and susceptibility of plants to necrotrophic and biotrophic pathogens.

    PubMed

    Barna, B; Fodor, J; Harrach, B D; Pogány, M; Király, Z

    2012-10-01

    Plant pathogens can be divided into biotrophs and necrotrophs according to their different life styles; biotrophs prefer living, while necrotrophs prefer dead cells for nutritional purposes. Therefore tissue necrosis caused by reactive oxygen species (ROS) during pathogen infection increases host susceptibility to necrotrophic, but resistance to biotrophic pathogen. Consequently, elevation of antioxidant capacity of plants enhances their tolerance to development of necroses caused by necrotrophic pathogens. Plant hormones can strongly influence induction of ROS and antioxidants, thereby influencing susceptibility or resistance of plants to pathogens. Pathogen-induced ROS themselves are considered as signaling molecules. Generally, salicylic acid (SA) signaling induces defense against biotrophic pathogens, whereas jasmonic acid (JA) against necrotrophic pathogens. Furthermore pathogens can modify plant's defense signaling network for their own benefit by changing phytohormone homeostasis. On the other hand, ROS are harmful also to the pathogens, consequently they try to defend themselves by elevating antioxidant activity and secreting ROS scavengers in the infected tissue. The Janus face nature of ROS and plant cell death on biotrophic and on necrotrophic pathogens is also supported by the experiments with BAX inhibitor-1 and the mlo mutation of Mlo gene in barley. It was found that ROS and elevated plant antioxidant activity play an important role in systemic acquired resistance (SAR) and induced systemic resistance (ISR), as well as in mycorrhiza induced abiotic and biotic stress tolerance of plants.

  12. Antifungal Activity of Decyl Gallate against Several Species of Pathogenic Fungi

    PubMed Central

    de Paula e Silva, Ana Carolina Alves; Costa-Orlandi, Caroline Barcelos; Gullo, Fernanda Patrícia; Sangalli-Leite, Fernanda; de Oliveira, Haroldo Cesar; da Silva, Julhiany de Fátima; Rossi, Suélen Andrea; Benaducci, Tatiane; Wolf, Vanessa Gonçalves; Regasini, Luis Octávio; Petrônio, Maicon Segalla; Silva, Dulce Helena Siqueira; Bolzani, Vanderlan S.; Mendes-Giannini, Maria José Soares

    2014-01-01

    This work aims to demonstrate that the gallic acid structure modification to the decyl gallate (G14) compound contributed to increase the antifungal activity against several species of pathogenic fungi, mainly, Candida spp., Cryptococcus spp., Paracoccidioides spp., and Histoplasma capsulatum, according to standardized microdilution method described by Clinical Laboratory Standard Institute (CLSI) documents. Moreover this compound has a particularly good selectivity index value, which makes it an excellent candidate for broad-spectrum antifungal prototype and encourages the continuation of subsequent studies for the discovery of its mechanism of action. PMID:25505923

  13. Hedgehogs and Mustelid Species: Major Carriers of Pathogenic Leptospira, a Survey in 28 Animal Species in France (20122015)

    PubMed Central

    Raton, Vincent; Zilber, Anne-Laure; Gasqui, Patrick; Faure, Eva; Baurier, Florence; Vourc’h, Gwenaël; Kodjo, Angeli; Combes, Benoît

    2016-01-01

    Human leptospirosis is a zoonotic and potentially fatal disease that has increasingly been reported in both developing and developed countries, including France. However, our understanding of the basic aspects of the epidemiology of this disease, including the source of Leptospira serogroup Australis infections in humans and domestic animals, remains incomplete. We investigated the genetic diversity of Leptospira in 28 species of wildlife other than rats using variable number tandem repeat (VNTR) and multispacer sequence typing (MST). The DNA of pathogenic Leptospira was detected in the kidney tissues of 201 individuals out of 3,738 tested individuals. A wide diversity, including 50 VNTR profiles and 8 MST profiles, was observed. Hedgehogs and mustelid species had the highest risk of being infected (logistic regression, OR = 66.8, CI95% = 30.9–144 and OR = 16.7, CI95% = 8.7–31.8, respectively). Almost all genetic profiles obtained from the hedgehogs were related to Leptospira interrogans Australis, suggesting the latter as a host-adapted bacterium, whereas mustelid species were infected by various genotypes, suggesting their interaction with Leptospira was different. By providing an inventory of the circulating strains of Leptospira and by pointing to hedgehogs as a potential reservoir of L. interrogans Australis, our study advances current knowledge on Leptospira animal carriers, and this information could serve to enhance epidemiological investigations in the future. PMID:27680672

  14. Hedgehogs and Mustelid Species: Major Carriers of Pathogenic Leptospira, a Survey in 28 Animal Species in France (20122015).

    PubMed

    Ayral, Florence; Djelouadji, Zoheira; Raton, Vincent; Zilber, Anne-Laure; Gasqui, Patrick; Faure, Eva; Baurier, Florence; Vourc'h, Gwenaël; Kodjo, Angeli; Combes, Benoît

    Human leptospirosis is a zoonotic and potentially fatal disease that has increasingly been reported in both developing and developed countries, including France. However, our understanding of the basic aspects of the epidemiology of this disease, including the source of Leptospira serogroup Australis infections in humans and domestic animals, remains incomplete. We investigated the genetic diversity of Leptospira in 28 species of wildlife other than rats using variable number tandem repeat (VNTR) and multispacer sequence typing (MST). The DNA of pathogenic Leptospira was detected in the kidney tissues of 201 individuals out of 3,738 tested individuals. A wide diversity, including 50 VNTR profiles and 8 MST profiles, was observed. Hedgehogs and mustelid species had the highest risk of being infected (logistic regression, OR = 66.8, CI95% = 30.9-144 and OR = 16.7, CI95% = 8.7-31.8, respectively). Almost all genetic profiles obtained from the hedgehogs were related to Leptospira interrogans Australis, suggesting the latter as a host-adapted bacterium, whereas mustelid species were infected by various genotypes, suggesting their interaction with Leptospira was different. By providing an inventory of the circulating strains of Leptospira and by pointing to hedgehogs as a potential reservoir of L. interrogans Australis, our study advances current knowledge on Leptospira animal carriers, and this information could serve to enhance epidemiological investigations in the future.

  15. Brevibacillus laterosporus, a Pathogen of Invertebrates and a Broad-Spectrum Antimicrobial Species

    PubMed Central

    Ruiu, Luca

    2013-01-01

    Brevibacillus laterosporus, a bacterium characterized by the production of a unique canoe-shaped lamellar body attached to one side of the spore, is a natural inhabitant of water, soil and insects. Its biopesticidal potential has been reported against insects in different orders including Coleoptera, Lepidoptera, Diptera and against nematodes and mollusks. In addition to its pathogenicity against invertebrates, different B. laterosporus strains show a broad-spectrum antimicrobial activity including activity against phytopathogenic bacteria and fungi. A wide variety of molecules, including proteins and antibiotics, have been associated with the observed pathogenicity and mode of action. Before being considered as a biological control agent against plant pathogens, the antifungal and antibacterial properties of certain B. laterosporus strains have found medical interest, associated with the production of antibiotics with therapeutic effects. The recent whole genome sequencing of this species revealed its potential to produce polyketides, nonribosomal peptides, and toxins. Another field of growing interest is the use of this bacterium for bioremediation of contaminated sites by exploiting its biodegradation properties. The aim of the present review is to gather and discuss all recent findings on this emerging entomopathogen, giving a wider picture of its complex and broad-spectrum biocontrol activity. PMID:26462431

  16. Brevibacillus laterosporus, a Pathogen of Invertebrates and a Broad-Spectrum Antimicrobial Species.

    PubMed

    Ruiu, Luca

    2013-09-05

    Brevibacillus laterosporus, a bacterium characterized by the production of a unique canoe-shaped lamellar body attached to one side of the spore, is a natural inhabitant of water, soil and insects. Its biopesticidal potential has been reported against insects in different orders including Coleoptera, Lepidoptera, Diptera and against nematodes and mollusks. In addition to its pathogenicity against invertebrates, different B. laterosporus strains show a broad-spectrum antimicrobial activity including activity against phytopathogenic bacteria and fungi. A wide variety of molecules, including proteins and antibiotics, have been associated with the observed pathogenicity and mode of action. Before being considered as a biological control agent against plant pathogens, the antifungal and antibacterial properties of certain B. laterosporus strains have found medical interest, associated with the production of antibiotics with therapeutic effects. The recent whole genome sequencing of this species revealed its potential to produce polyketides, nonribosomal peptides, and toxins. Another field of growing interest is the use of this bacterium for bioremediation of contaminated sites by exploiting its biodegradation properties. The aim of the present review is to gather and discuss all recent findings on this emerging entomopathogen, giving a wider picture of its complex and broad-spectrum biocontrol activity.

  17. Deep-sea hydrothermal vent bacteria related to human pathogenic Vibrio species

    PubMed Central

    Hasan, Nur A.; Grim, Christopher J.; Lipp, Erin K.; Rivera, Irma N. G.; Chun, Jongsik; Haley, Bradd J.; Taviani, Elisa; Choi, Seon Young; Hoq, Mozammel; Munk, A. Christine; Brettin, Thomas S.; Bruce, David; Challacombe, Jean F.; Detter, J. Chris; Han, Cliff S.; Eisen, Jonathan A.; Huq, Anwar; Colwell, Rita R.

    2015-01-01

    Vibrio species are both ubiquitous and abundant in marine coastal waters, estuaries, ocean sediment, and aquaculture settings worldwide. We report here the isolation, characterization, and genome sequence of a novel Vibrio species, Vibrio antiquarius, isolated from a mesophilic bacterial community associated with hydrothermal vents located along the East Pacific Rise, near the southwest coast of Mexico. Genomic and phenotypic analysis revealed V. antiquarius is closely related to pathogenic Vibrio species, namely Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi, and Vibrio vulnificus, but sufficiently divergent to warrant a separate species status. The V. antiquarius genome encodes genes and operons with ecological functions relevant to the environment conditions of the deep sea and also harbors factors known to be involved in human disease caused by freshwater, coastal, and brackish water vibrios. The presence of virulence factors in this deep-sea Vibrio species suggests a far more fundamental role of these factors for their bacterial host. Comparative genomics revealed a variety of genomic events that may have provided an important driving force in V. antiquarius evolution, facilitating response to environmental conditions of the deep sea. PMID:25964331

  18. Phylogenomics and molecular signatures for species from the plant pathogen-containing order xanthomonadales.

    PubMed

    Naushad, Hafiz Sohail; Gupta, Radhey S

    2013-01-01

    The species from the order Xanthomonadales, which harbors many important plant pathogens and some human pathogens, are currently distinguished primarily on the basis of their branching in the 16S rRNA tree. No molecular or biochemical characteristic is known that is specific for these bacteria. Phylogenetic and comparative analyses were conducted on 26 sequenced Xanthomonadales genomes to delineate their branching order and to identify molecular signatures consisting of conserved signature indels (CSIs) in protein sequences that are specific for these bacteria. In a phylogenetic tree based upon sequences for 28 proteins, Xanthomonadales species formed a strongly supported clade with Rhodanobacter sp. 2APBS1 as its deepest branch. Comparative analyses of protein sequences have identified 13 CSIs in widely distributed proteins such as GlnRS, TypA, MscL, LysRS, LipA, Tgt, LpxA, TolQ, ParE, PolA and TyrB that are unique to all species/strains from this order, but not found in any other bacteria. Fifteen additional CSIs in proteins (viz. CoxD, DnaE, PolA, SucA, AsnB, RecA, PyrG, LigA, MutS and TrmD) are uniquely shared by different Xanthomonadales except Rhodanobacter and in a few cases by Pseudoxanthomonas species, providing further support for the deep branching of these two genera. Five other CSIs are commonly shared by Xanthomonadales and 1-3 species from the orders Chromatiales, Methylococcales and Cardiobacteriales suggesting that these deep branching orders of Gammaproteobacteria might be specifically related. Lastly, 7 CSIs in ValRS, CarB, PyrE, GlyS, RnhB, MinD and X001065 are commonly shared by Xanthomonadales and a limited number of Beta- or Gamma-proteobacteria. Our analysis indicates that these CSIs have likely originated independently and they are not due to lateral gene transfers. The Xanthomonadales-specific CSIs reported here provide novel molecular markers for the identification of these important plant and human pathogens and also as potential targets

  19. Phylogenomics and Molecular Signatures for Species from the Plant Pathogen-Containing Order Xanthomonadales

    PubMed Central

    Naushad, Hafiz Sohail; Gupta, Radhey S.

    2013-01-01

    The species from the order Xanthomonadales, which harbors many important plant pathogens and some human pathogens, are currently distinguished primarily on the basis of their branching in the 16S rRNA tree. No molecular or biochemical characteristic is known that is specific for these bacteria. Phylogenetic and comparative analyses were conducted on 26 sequenced Xanthomonadales genomes to delineate their branching order and to identify molecular signatures consisting of conserved signature indels (CSIs) in protein sequences that are specific for these bacteria. In a phylogenetic tree based upon sequences for 28 proteins, Xanthomonadales species formed a strongly supported clade with Rhodanobacter sp. 2APBS1 as its deepest branch. Comparative analyses of protein sequences have identified 13 CSIs in widely distributed proteins such as GlnRS, TypA, MscL, LysRS, LipA, Tgt, LpxA, TolQ, ParE, PolA and TyrB that are unique to all species/strains from this order, but not found in any other bacteria. Fifteen additional CSIs in proteins (viz. CoxD, DnaE, PolA, SucA, AsnB, RecA, PyrG, LigA, MutS and TrmD) are uniquely shared by different Xanthomonadales except Rhodanobacter and in a few cases by Pseudoxanthomonas species, providing further support for the deep branching of these two genera. Five other CSIs are commonly shared by Xanthomonadales and 1–3 species from the orders Chromatiales, Methylococcales and Cardiobacteriales suggesting that these deep branching orders of Gammaproteobacteria might be specifically related. Lastly, 7 CSIs in ValRS, CarB, PyrE, GlyS, RnhB, MinD and X001065 are commonly shared by Xanthomonadales and a limited number of Beta- or Gamma-proteobacteria. Our analysis indicates that these CSIs have likely originated independently and they are not due to lateral gene transfers. The Xanthomonadales-specific CSIs reported here provide novel molecular markers for the identification of these important plant and human pathogens and also as potential

  20. Pathogenic Leptospira species express surface-exposed proteins belonging to the bacterial immunoglobulin superfamily

    PubMed Central

    Matsunaga, James; Barocchi, Michele A.; Croda, Julio; Young, Tracy A.; Sanchez, Yolanda; Siqueira, Isadora; Bolin, Carole A.; Reis, Mitermayer G.; Riley, Lee W.; Haake, David A.; Ko, Albert I.

    2005-01-01

    Summary Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L. interrogans and L. kirschneri expression libraries with sera from leptospirosis patients identified 13 lambda phage clones that encode tandem repeats of the 90 amino acid Big domain. Two lig genes, designated ligA and ligB, and one pseudo-gene, ligC, were identified. The ligA and ligB genes encode amino-terminal lipoprotein signal peptides followed by 10 or 11 Big domain repeats and, in the case of ligB, a unique carboxy-terminal non-repeat domain. The organization of ligC is similar to that of ligB but contains mutations that disrupt the reading frame. The lig sequences are present in pathogenic but not saprophytic Leptospira species. LigA and LigB are expressed by a variety of virulent leptospiral strains. Loss of Lig protein and RNA transcript expression is correlated with the observed loss of virulence during culture attenuation of pathogenic strains. High-pressure freeze substitution followed by immunocytochemical electron microscopy confirmed that the Lig proteins were localized to the bacterial surface. Immunoblot studies with patient sera found that the Lig proteins are a major antigen recognized during the acute host infection. These observations demonstrate that the Lig proteins are a newly identified surface protein of pathogenic Leptospira, which by analogy to other bacterial immunoglobulin superfamily virulence factors, may play a role in host cell attachment and invasion during leptospiral pathogenesis. PMID:12890019

  1. Identification of Candidate Periodontal Pathogens and Beneficial Species by Quantitative 16S Clonal Analysis†

    PubMed Central

    Kumar, Purnima S.; Griffen, Ann L.; Moeschberger, Melvin L.; Leys, Eugene J.

    2005-01-01

    Most studies of the bacterial etiology of periodontitis have used either culture-based or targeted DNA approaches, and so it is likely that pathogens remain undiscovered. The purpose of this study was to use culture-independent, quantitative analysis of biofilms associated with chronic periodontitis and periodontal health to identify pathogens and beneficial species. Samples from subjects with periodontitis and controls were analyzed using ribosomal 16S cloning and sequencing. Several genera, many of them uncultivated, were associated with periodontitis, the most numerous of which were gram positive, including Peptostreptococcus and Filifactor. The genera Megasphaera and Desulfobulbus were elevated in periodontitis, and the levels of several species or phylotypes of Campylobacter, Selenomonas, Deferribacteres, Dialister, Catonella, Tannerella, Streptococcus, Atopobium, Eubacterium, and Treponema were elevated in disease. Streptococcus and Veillonella spp. were found in high numbers in all samples and accounted for a significantly greater fraction of the microbial community in healthy subjects than in those with periodontitis. The microbial profile of periodontal health also included the less-abundant genera Campylobacter, Abiotrophia, Gemella, Capnocytophaga, and Neisseria. These newly identified candidates outnumbered Porphyromonas gingivalis and other species previously implicated as periodontopathogens, and it is not clear if newly identified and more numerous species may play a more important role in pathogenesis. Finally, more differences were found in the bacterial profile between subjects with periodontitis and healthy subjects than between deep and shallow sites within the same subject. This suggests that chronic periodontitis is the result of a global perturbation of the oral bacterial ecology rather than a disease-site specific microbial shift. PMID:16081935

  2. Pathogenic Rickettsia Species Acquire Vitronectin from Human Serum to Promote Resistance to Complement-mediated Killing

    PubMed Central

    Riley, Sean P.; Patterson, Jennifer L.; Nava, Samantha; Martinez, Juan J.

    2014-01-01

    SUMMARY Bacteria of the genus Rickettsia are transmitted from arthropod vectors and primarily infect cells of the mammalian endothelial system. Throughout this infectious cycle, the bacteria are exposed to the deleterious effects of serum complement. Using Rickettsia conorii, the etiologic agent of Mediterranean spotted fever (MSF), as a model rickettsial species, we have previously demonstrated that this class of pathogen interacts with human factor H to mediate partial survival in human serum. Herein, we demonstrate that R. conorii also interacts with the terminal complement complex inhibitor vitronectin (Vn). We further demonstrate that an evolutionarily conserved rickettsial antigen, Adr1/RC1281, interacts with human vitronectin and is sufficient to mediate resistance to serum killing when expressed at the outer-membrane of serum sensitive E. coli. Adr1 is an integral outer-membrane protein whose structure is predicted to contain eight membrane-embedded β-strands and four “loop” regions that are exposed to extracellular milieu. Site-directed mutagenesis of Adr1 revealed that at least two predicted “loop” regions are required to mediate resistance to complement-mediated killing and vitronectin acquisition. These results demonstrate that rickettsial species have evolved multiple mechanisms to evade complement deposition and that evasion of killing in serum is an evolutionarily conserved virulence attribute for this genus of obligate intracellular pathogens. PMID:24286496

  3. Comparison of the pathogen species-specific immune response in udder derived cell types and their models.

    PubMed

    Günther, Juliane; Koy, Mirja; Berthold, Anne; Schuberth, Hans-Joachim; Seyfert, Hans-Martin

    2016-02-01

    The outcome of an udder infection (mastitis) largely depends on the species of the invading pathogen. Gram-negative pathogens, such as Escherichia coli often elicit acute clinical mastitis while Gram-positive pathogens, such as Staphylococcus aureus tend to cause milder subclinical inflammations. It is unclear which type of the immune competent cells residing in the udder governs the pathogen species-specific physiology of mastitis and which established cell lines might provide suitable models. We therefore profiled the pathogen species-specific immune response of different cell types derived from udder and blood. Primary cultures of bovine mammary epithelial cells (pbMEC), mammary derived fibroblasts (pbMFC), and bovine monocyte-derived macrophages (boMdM) were challenged with heat-killed E. coli, S. aureus and S. uberis mastitis pathogens and their immune response was scaled against the response of established models for MEC (bovine MAC-T) and macrophages (murine RAW 264.7). Only E. coli provoked a full scale immune reaction in pbMEC, fibroblasts and MAC-T cells, as indicated by induced cytokine and chemokine expression and NF-κB activation. Weak reactions were induced by S. aureus and none by S. uberis challenges. In contrast, both models for macrophages (boMdM and RAW 264.7) reacted strongly against all the three pathogens accompanied by strong activation of NF-κB factors. Hence, the established cell models MAC-T and RAW 264.7 properly reflected key aspects of the pathogen species-specific immune response of the respective parental cell type. Our data imply that the pathogen species-specific physiology of mastitis likely relates to the respective response of MEC rather to that of professional immune cells.

  4. Evaluation of different enrichment methods for pathogenic Yersinia species detection by real time PCR

    PubMed Central

    2014-01-01

    Background Yersiniosis is a zoonotic disease reported worldwide. Culture and PCR based protocols are the most common used methods for detection of pathogenic Yersinia species in animal samples. PCR sensitivity could be increased by an initial enrichment step. This step is particularly useful in surveillance programs, where PCR is applied to samples from asymptomatic animals. The aim of this study was to evaluate the improvement in pathogenic Yersinia species detection using a suitable enrichment method prior to the real time PCR (rtPCR). Nine different enrichment protocols were evaluated including six different broth mediums (CASO, ITC, PSB, PBS, PBSMSB and PBSSSB). Results The analysis of variance showed significant differences in Yersinia detection by rtPCR according to the enrichment protocol used. These differences were higher for Y. pseudotuberculosis than for Y. enterocolitica. In general, samples incubated at lower temperatures yielded the highest detection rates. The best results were obtained with PBSMSB and PBS2. Application of PBSMSB protocol to free-ranging wild board samples improved the detection of Y. enterocolitica by 21.2% when compared with direct rtPCR. Y. pseudotuberculosis detection was improved by 10.6% when results obtained by direct rtPCR and by PBSMSB enrichment before rtPCR were analyzed in combination. Conclusions The data obtained in the present study indicate a difference in Yersinia detection by rtPCR related to the enrichment protocol used, being PBSMSB enrichment during 15 days at 4°C and PBS during 7 days at 4°C the most efficient. The use of direct rtPCR in combination with PBSMSB enrichment prior to rtPCR resulted in an improvement in the detection rates of pathogenic Yersinia in wild boar and could be useful for application in other animal samples. PMID:25168886

  5. Pathogenic bacterial species associated with endodontic infection evade innate immune control by disabling neutrophils.

    PubMed

    Matsui, Aritsune; Jin, Jun-O; Johnston, Christopher D; Yamazaki, Hajime; Houri-Haddad, Yael; Rittling, Susan R

    2014-10-01

    Endodontic infections, in which oral bacteria access the tooth pulp chamber, are common and do not resolve once established. To investigate the effects of these infections on the innate immune response, we established a mouse subcutaneous chamber model, where a mixture of four oral pathogens commonly associated with these infections (endodontic pathogens [EP]), i.e., Fusobacterium nucleatum, Streptococcus intermedius, Parvimonas micra, and Prevotella intermedia, was inoculated into subcutaneously implanted titanium chambers. Cells that infiltrated the chamber after these infections were primarily neutrophils; however, these neutrophils were unable to control the infection. Infection with a nonpathogenic oral bacterial species, Streptococcus mitis, resulted in well-controlled infection, with bacterial numbers reduced by 4 to 5 log units after 7 days. Propidium iodide (PI) staining of the chamber neutrophils identified three distinct populations: neutrophils from EP-infected chambers were intermediate in PI staining, while cells in chambers from mice infected with S. mitis were PI positive (apoptotic) or negative (live). Strikingly, neutrophils from EP-infected chambers were severely impaired in their ability to phagocytose and to generate reactive oxygen species in vitro after removal from the chamber compared to cells from S. mitis-infected chambers. The mechanism of neutrophil impairment was necrotic cell death as determined by morphological analyses. P. intermedia alone could induce a similar neutrophil phenotype. We conclude that the endodontic pathogens, particularly P. intermedia, can efficiently disable and kill infiltrating neutrophils, allowing these infections to become established. These results can help explain the persistence of endodontic infections and demonstrate a new virulence mechanism associated with P. intermedia.

  6. Pathogenic Bacterial Species Associated with Endodontic Infection Evade Innate Immune Control by Disabling Neutrophils

    PubMed Central

    Matsui, Aritsune; Jin, Jun-O; Johnston, Christopher D.; Yamazaki, Hajime; Houri-Haddad, Yael

    2014-01-01

    Endodontic infections, in which oral bacteria access the tooth pulp chamber, are common and do not resolve once established. To investigate the effects of these infections on the innate immune response, we established a mouse subcutaneous chamber model, where a mixture of four oral pathogens commonly associated with these infections (endodontic pathogens [EP]), i.e., Fusobacterium nucleatum, Streptococcus intermedius, Parvimonas micra, and Prevotella intermedia, was inoculated into subcutaneously implanted titanium chambers. Cells that infiltrated the chamber after these infections were primarily neutrophils; however, these neutrophils were unable to control the infection. Infection with a nonpathogenic oral bacterial species, Streptococcus mitis, resulted in well-controlled infection, with bacterial numbers reduced by 4 to 5 log units after 7 days. Propidium iodide (PI) staining of the chamber neutrophils identified three distinct populations: neutrophils from EP-infected chambers were intermediate in PI staining, while cells in chambers from mice infected with S. mitis were PI positive (apoptotic) or negative (live). Strikingly, neutrophils from EP-infected chambers were severely impaired in their ability to phagocytose and to generate reactive oxygen species in vitro after removal from the chamber compared to cells from S. mitis-infected chambers. The mechanism of neutrophil impairment was necrotic cell death as determined by morphological analyses. P. intermedia alone could induce a similar neutrophil phenotype. We conclude that the endodontic pathogens, particularly P. intermedia, can efficiently disable and kill infiltrating neutrophils, allowing these infections to become established. These results can help explain the persistence of endodontic infections and demonstrate a new virulence mechanism associated with P. intermedia. PMID:25024367

  7. Tree species effects on pathogen-suppressive capacities of soil bacteria across two tropical dry forests in Costa Rica.

    PubMed

    Becklund, Kristen; Powers, Jennifer; Kinkel, Linda

    2016-11-01

    Antibiotic-producing bacteria in the genus Streptomyces can inhibit soil-borne plant pathogens, and have the potential to mediate the impacts of disease on plant communities. Little is known about how antibiotic production varies among soil communities in tropical forests, despite a long history of interest in the role of soil-borne pathogens in these ecosystems. Our objective was to determine how tree species and soils influence variation in antibiotic-mediated pathogen suppression among Streptomyces communities in two tropical dry forest sites (Santa Rosa and Palo Verde). We targeted tree species that co-occur in both sites and used a culture-based functional assay to quantify pathogen-suppressive capacities of Streptomyces communities beneath 50 focal trees. We also measured host-associated litter and soil element concentrations as potential mechanisms by which trees may influence soil microbes. Pathogen-suppressive capacities of Streptomyces communities varied within and among tree species, and inhibitory phenotypes were significantly related to soil and litter element concentrations. Average proportions of inhibitory Streptomyces in soils from the same tree species varied between 1.6 and 3.3-fold between sites. Densities and proportions of pathogen-suppressive bacteria were always higher in Santa Rosa than Palo Verde. Our results suggest that spatial heterogeneity in the potential for antibiotic-mediated disease suppression is shaped by tree species, site, and soil characteristics, which could have significant implications for understanding plant community composition and diversity in tropical dry forests.

  8. Sensitive and rapid RT-qPCR quantification of pathogenic Candida species in human blood.

    PubMed

    Ogata, Kiyohito; Matsuda, Kazunori; Tsuji, Hirokazu; Nomoto, Koji

    2015-10-01

    For accurate diagnosis and appropriate treatment of candidiasis, we developed a highly sensitive quantitative RT-PCR (RT-qPCR) system for five Candida species that have been reported to be the major causes of bloodstream fungal infection (Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei), together with a system for all pathogenic Candida species. Cells of each fungal species spiked into human peripheral blood (PB) were specifically detected at a lower detection limit of 10(0) cell/1 mL PB by this system using the newly developed specific primer sets targeting 18S or 26S rRNA of the five Candida species, together with the existing group primer set. The total count of the five Candida spp. as the sum of those obtained by using the five species primer sets was equivalent to the count obtained by using the group primer set, indicating that the group set covered the major five Candida spp. in human blood with the same degree of accuracy as the species primer sets. The RT-qPCR counts of the Candida species were in good agreement with CFU counts obtained by their culture on CHROMagar™, with a lower detection limit of 10(0)cell/mL of PB. Candida rRNA molecules were stably stored for at least 7 days at 4°C by keeping the blood specimens in an RNA stabilizing reagent. These results strongly suggest that this sensitive system is useful for accurate and rapid diagnosis of Candida bloodstream infections.

  9. Endophytic and pathogenic Phyllosticta species, with reference to those associated with Citrus Black Spot.

    PubMed

    Glienke, C; Pereira, O L; Stringari, D; Fabris, J; Kava-Cordeiro, V; Galli-Terasawa, L; Cunnington, J; Shivas, R G; Groenewald, J Z; Crous, P W

    2011-06-01

    We investigated the identity and genetic diversity of more than 100 isolates belonging to Phyllosticta (teleomorph Guignardia), with particular emphasis on Phyllosticta citricarpa and Guignardia mangiferae s.l. occurring on Citrus. Phyllosticta citricarpa is the causal agent of Citrus Black Spot and is subject to phytosanitary legislation in the EU. This species is frequently confused with a taxon generally referred to as G. mangiferae, the presumed teleomorph of P. capitalensis, which is a non-pathogenic endophyte, commonly isolated from citrus leaves and fruits and a wide range of other hosts. DNA sequence analysis of the nrDNA internal transcribed spacer region (ITS1, 5.8S nrDNA, ITS2) and partial translation elongation factor 1-alpha (TEF1), actin and glyceraldehyde-3-phosphate dehydrogenase (GPDH) genes resolved nine clades correlating to seven known, and two apparently undescribed species. Phyllosticta citribraziliensis is newly described as an endophytic species occurring on Citrus in Brazil. An epitype is designated for P. citricarpa from material newly collected in Australia, which is distinct from P. citriasiana, presently only known on C. maxima from Asia. Phyllosticta bifrenariae is newly described for a species causing leaf and bulb spots on Bifrenaria harrisoniae (Orchidaceae) in Brazil. It is morphologically distinct from P. capitalensis, which was originally described from Stanhopea (Orchidaceae) in Brazil; an epitype is designated here. Guignardia mangiferae, which was originally described from Mangifera indica (Anacardiaceae) in India, is distinguished from the non-pathogenic endophyte, P. brazilianiae sp. nov., which is common on M. indica in Brazil. Furthermore, a combined phylogenetic tree revealed the P. capitalensis s.l. clade to be genetically distinct from the reference isolate of G. mangiferae. Several names are available for this clade, the oldest being P. capitalensis. These results suggest that endophytic, non-pathogenic isolates

  10. Role of the Pre-neck Appendage Protein (Dpo7) from Phage vB_SepiS-phiIPLA7 as an Anti-biofilm Agent in Staphylococcal Species

    PubMed Central

    Gutiérrez, Diana; Briers, Yves; Rodríguez-Rubio, Lorena; Martínez, Beatriz; Rodríguez, Ana; Lavigne, Rob; García, Pilar

    2015-01-01

    Staphylococcus epidermidis and Staphylococcus aureus are important causative agents of hospital-acquired infections and bacteremia, likely due to their ability to form biofilms. The production of a dense exopolysaccharide (EPS) matrix enclosing the cells slows the penetration of antibiotic down, resulting in therapy failure. The EPS depolymerase (Dpo7) derived from bacteriophage vB_SepiS-phiIPLA7, was overexpressed in Escherichia coli and characterized. A dose dependent but time independent response was observed after treatment of staphylococcal 24 h-biofilms with Dpo7. Maximum removal (>90%) of biofilm-attached cells was obtained with 0.15 μM of Dpo7 in all polysaccharide producer strains but Dpo7 failed to eliminate polysaccharide-independent biofilm formed by S. aureus V329. Moreover, the pre-treatment of polystyrene surfaces with Dpo7 reduced the biofilm biomass by 53–85% in the 67% of the tested strains. This study supports the use of phage-encoded EPS depolymerases to prevent and disperse staphylococcal biofilms, thereby making bacteria more susceptible to the action of antimicrobials. PMID:26635776

  11. Investigating Differences across Host Species and Scales to Explain the Distribution of the Amphibian Pathogen Batrachochytrium dendrobatidis

    PubMed Central

    Peterson, Anna C.; McKenzie, Valerie J.

    2014-01-01

    Many pathogens infect more than one host species, and clarifying how these different hosts contribute to pathogen dynamics can facilitate the management of pathogens and can lend insight into the functioning of pathogens in ecosystems. In this study, we investigated a suite of native and non-native amphibian hosts of the pathogen Batrachochytrium dendrobatidis (Bd) across multiple scales to identify potential mechanisms that may drive infection patterns in the Colorado study system. Specifically, we aimed to determine if: 1) amphibian populations vary in Bd infection across the landscape, 2) amphibian community composition predicts infection (e.g., does the presence or abundance of any particular species influence infection in others?), 3) amphibian species vary in their ability to produce infectious zoospores in a laboratory infection, 4) heterogeneity in host ability observed in the laboratory scales to predict patterns of Bd prevalence in the landscape. We found that non-native North American bullfrogs (Lithobates catesbeianus) are widespread and have the highest prevalence of Bd infection relative to the other native species in the landscape. Additionally, infection in some native species appears to be related to the density of sympatric L. catesbeianus populations. At the smaller host scale, we found that L. catesbeianus produces more of the infective zoospore stage relative to some native species, but that this zoospore output does not scale to predict infection in sympatric wild populations of native species. Rather, landscape level infection relates most strongly to density of hosts at a wetland as well as abiotic factors. While non-native L. catesbeianus have high levels of Bd infection in the Colorado Front Range system, we also identified Bd infection in a number of native amphibian populations allopatric with L. catesbeianus, suggesting that multiple host species are important contributors to the dynamics of the Bd pathogen in this landscape. PMID

  12. Phylogenetics and Taxonomy of the Fungal Vascular Wilt Pathogen Verticillium, with the Descriptions of Five New Species

    PubMed Central

    Inderbitzin, Patrik; Bostock, Richard M.; Davis, R. Michael; Usami, Toshiyuki; Platt, Harold W.; Subbarao, Krishna V.

    2011-01-01

    Knowledge of pathogen biology and genetic diversity is a cornerstone of effective disease management, and accurate identification of the pathogen is a foundation of pathogen biology. Species names provide an ideal framework for storage and retrieval of relevant information, a system that is contingent on a clear understanding of species boundaries and consistent species identification. Verticillium, a genus of ascomycete fungi, contains important plant pathogens whose species boundaries have been ill defined. Using phylogenetic analyses, morphological investigations and comparisons to herbarium material and the literature, we established a taxonomic framework for Verticillium comprising ten species, five of which are new to science. We used a collection of 74 isolates representing much of the diversity of Verticillium, and phylogenetic analyses based on the ribosomal internal transcribed spacer region (ITS), partial sequences of the protein coding genes actin (ACT), elongation factor 1-alpha (EF), glyceraldehyde-3-phosphate dehydrogenase (GPD) and tryptophan synthase (TS). Combined analyses of the ACT, EF, GPD and TS datasets recognized two major groups within Verticillium, Clade Flavexudans and Clade Flavnonexudans, reflecting the respective production and absence of yellow hyphal pigments. Clade Flavexudans comprised V. albo-atrum and V. tricorpus as well as the new species V. zaregamsianum, V. isaacii and V. klebahnii, of which the latter two were morphologically indistinguishable from V. tricorpus but may differ in pathogenicity. Clade Flavnonexudans comprised V. nubilum, V. dahliae and V. longisporum, as well as the two new species V. alfalfae and V. nonalfalfae, which resembled the distantly related V. albo-atrum in morphology. Apart from the diploid hybrid V. longisporum, each of the ten species corresponded to a single clade in the phylogenetic tree comprising just one ex-type strain, thereby establishing a direct link to a name tied to a herbarium specimen

  13. Phylogenetics and taxonomy of the fungal vascular wilt pathogen Verticillium, with the descriptions of five new species.

    PubMed

    Inderbitzin, Patrik; Bostock, Richard M; Davis, R Michael; Usami, Toshiyuki; Platt, Harold W; Subbarao, Krishna V

    2011-01-01

    Knowledge of pathogen biology and genetic diversity is a cornerstone of effective disease management, and accurate identification of the pathogen is a foundation of pathogen biology. Species names provide an ideal framework for storage and retrieval of relevant information, a system that is contingent on a clear understanding of species boundaries and consistent species identification. Verticillium, a genus of ascomycete fungi, contains important plant pathogens whose species boundaries have been ill defined. Using phylogenetic analyses, morphological investigations and comparisons to herbarium material and the literature, we established a taxonomic framework for Verticillium comprising ten species, five of which are new to science. We used a collection of 74 isolates representing much of the diversity of Verticillium, and phylogenetic analyses based on the ribosomal internal transcribed spacer region (ITS), partial sequences of the protein coding genes actin (ACT), elongation factor 1-alpha (EF), glyceraldehyde-3-phosphate dehydrogenase (GPD) and tryptophan synthase (TS). Combined analyses of the ACT, EF, GPD and TS datasets recognized two major groups within Verticillium, Clade Flavexudans and Clade Flavnonexudans, reflecting the respective production and absence of yellow hyphal pigments. Clade Flavexudans comprised V. albo-atrum and V. tricorpus as well as the new species V. zaregamsianum, V. isaacii and V. klebahnii, of which the latter two were morphologically indistinguishable from V. tricorpus but may differ in pathogenicity. Clade Flavnonexudans comprised V. nubilum, V. dahliae and V. longisporum, as well as the two new species V. alfalfae and V. nonalfalfae, which resembled the distantly related V. albo-atrum in morphology. Apart from the diploid hybrid V. longisporum, each of the ten species corresponded to a single clade in the phylogenetic tree comprising just one ex-type strain, thereby establishing a direct link to a name tied to a herbarium specimen

  14. Pathogenic and saprophytic Leptospira species in water and soils from selected urban sites in peninsular Malaysia.

    PubMed

    Benacer, Douadi; Woh, Pei Yee; Mohd Zain, Siti Nursheena; Amran, Fairuz; Thong, Kwai Lin

    2013-01-01

    Leptospira species were studied in water and soils from selected urban sites in Malaysia. A total of 151 water (n=121) and soil (n=30) samples were collected from 12 recreational lakes and wet markets. All samples were filtered and inoculated into semi-solid Ellinghausen and McCullough modified by Johnson and Harris (EMJH) media supplemented with additional 5-fluorouracil. The cultures were then incubated at 30°C and observed under a dark field microscope with intervals of 10 days. A PCR assay targeting the rrs gene was used to confirm the genus Leptospira among the isolates. Subsequently, the pathogenic status of the isolates was determined using primer sets G1/G2 and Sapro1/Sapro2, which target the secY and rrs genes, respectively. The isolates were identified at serogroup level using the microscopic agglutination test (MAT) while their genetic diversity was assessed by pulsed field gel electrophoresis (PFGE). Based on dark field microscopy, 23.1% (28/121) water and 23.3% (7/30) soil cultures were positive for Leptospira spp. Of the 35 positive cultures, only 8 were pure and confirmed as Leptospira genus by PCR assay. Two out of 8 isolates were confirmed as pathogenic, 5 were saprophytic and one was intermediate. These 8 isolates were negative for the 25 reference hyperimmune rabbit sera tested in the MAT. PFGE showed that all 8 of these environmental Leptospira spp. were genetically diverse. In conclusion, the presence of pathogenic Leptospira spp. in the urban Malaysian environment may indicate and highlight the importance of water screening, especially in recreational lakes, in order to minimize any chance of Leptospira infection.

  15. Pathogenic and Saprophytic Leptospira Species in Water and Soils from Selected Urban Sites in Peninsular Malaysia

    PubMed Central

    Benacer, Douadi; Woh, Pei Yee; Mohd Zain, Siti Nursheena; Amran, Fairuz; Thong, Kwai Lin

    2013-01-01

    Leptospira species were studied in water and soils from selected urban sites in Malaysia. A total of 151 water (n=121) and soil (n=30) samples were collected from 12 recreational lakes and wet markets. All samples were filtered and inoculated into semi-solid Ellinghausen and McCullough modified by Johnson and Harris (EMJH) media supplemented with additional 5-fluorouracil. The cultures were then incubated at 30°C and observed under a dark field microscope with intervals of 10 days. A PCR assay targeting the rrs gene was used to confirm the genus Leptospira among the isolates. Subsequently, the pathogenic status of the isolates was determined using primer sets G1/G2 and Sapro1/Sapro2, which target the secY and rrs genes, respectively. The isolates were identified at serogroup level using the microscopic agglutination test (MAT) while their genetic diversity was assessed by pulsed field gel electrophoresis (PFGE). Based on dark field microscopy, 23.1% (28/121) water and 23.3% (7/30) soil cultures were positive for Leptospira spp. Of the 35 positive cultures, only 8 were pure and confirmed as Leptospira genus by PCR assay. Two out of 8 isolates were confirmed as pathogenic, 5 were saprophytic and one was intermediate. These 8 isolates were negative for the 25 reference hyperimmune rabbit sera tested in the MAT. PFGE showed that all 8 of these environmental Leptospira spp. were genetically diverse. In conclusion, the presence of pathogenic Leptospira spp. in the urban Malaysian environment may indicate and highlight the importance of water screening, especially in recreational lakes, in order to minimize any chance of Leptospira infection. PMID:23363618

  16. Predicting copper-, iron-, and zinc-binding proteins in pathogenic species of the Paracoccidioides genus

    PubMed Central

    Tristão, Gabriel B.; Assunção, Leandro do Prado; dos Santos, Luiz Paulo A.; Borges, Clayton L.; Silva-Bailão, Mirelle Garcia; Soares, Célia M. de Almeida; Cavallaro, Gabriele; Bailão, Alexandre M.

    2015-01-01

    Approximately one-third of all proteins have been estimated to contain at least one metal cofactor, and these proteins are referred to as metalloproteins. These represent one of the most diverse classes of proteins, containing metal ions that bind to specific sites to perform catalytic, regulatory and structural functions. Bioinformatic tools have been developed to predict metalloproteins encoded by an organism based only on its genome sequence. Its function and the type of metal binder can also be predicted via a bioinformatics approach. Paracoccidioides complex includes termodimorphic pathogenic fungi that are found as saprobic mycelia in the environment and as yeast, the parasitic form, in host tissues. They are the etiologic agents of Paracoccidioidomycosis, a prevalent systemic mycosis in Latin America. Many metalloproteins are important for the virulence of several pathogenic microorganisms. Accordingly, the present work aimed to predict the copper, iron and zinc proteins encoded by the genomes of three phylogenetic species of Paracoccidioides (Pb01, Pb03, and Pb18). The metalloproteins were identified using bioinformatics approaches based on structure, annotation and domains. Cu-, Fe-, and Zn-binding proteins represent 7% of the total proteins encoded by Paracoccidioides spp. genomes. Zinc proteins were the most abundant metalloproteins, representing 5.7% of the fungus proteome, whereas copper and iron proteins represent 0.3 and 1.2%, respectively. Functional classification revealed that metalloproteins are related to many cellular processes. Furthermore, it was observed that many of these metalloproteins serve as virulence factors in the biology of the fungus. Thus, it is concluded that the Cu, Fe, and Zn metalloproteomes of the Paracoccidioides spp. are of the utmost importance for the biology and virulence of these particular human pathogens. PMID:25620964

  17. Phosphorus limitation, soil-borne pathogens and the coexistence of plant species in hyperdiverse forests and shrublands.

    PubMed

    Laliberté, Etienne; Lambers, Hans; Burgess, Treena I; Wright, S Joseph

    2015-04-01

    Hyperdiverse forests occur in the lowland tropics, whereas the most species-rich shrublands are found in regions such as south-western Australia (kwongan) and South Africa (fynbos). Despite large differences, these ecosystems share an important characteristic: their soils are strongly weathered and phosphorus (P) is a key growth-limiting nutrient. Soil-borne pathogens are increasingly being recognized as drivers of plant diversity in lowland tropical rainforests, but have received little attention in species-rich shrublands. We suggest a trade-off in which the species most proficient at acquiring P have ephemeral roots that are particularly susceptible to soil-borne pathogens. This could equalize out the differences in competitive ability among co-occurring species in these ecosystems, thus contributing to coexistence. Moreover, effective protection against soil-borne pathogens by ectomycorrhizal (ECM) fungi might explain the occurrence of monodominant stands of ECM trees and shrubs amongst otherwise species-rich communities. We identify gaps in our knowledge which need to be filled in order to evaluate a possible link between P limitation, fine root traits, soil-borne pathogens and local plant species diversity. Such a link may help to explain how numerous plant species can coexist in hyperdiverse rainforests and shrublands, and, conversely, how monodominant stands can develop in these ecosystems.

  18. Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California.

    PubMed

    Straub, Mary H; Kelly, Terra R; Rideout, Bruce A; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K

    2015-01-01

    Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats.

  19. Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

    PubMed Central

    Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce A.; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K.

    2015-01-01

    Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. PMID:26606755

  20. Diversity of Aquatic Pseudomonas Species and Their Activity against the Fish Pathogenic Oomycete Saprolegnia.

    PubMed

    Liu, Yiying; Rzeszutek, Elzbieta; van der Voort, Menno; Wu, Cheng-Hsuan; Thoen, Even; Skaar, Ida; Bulone, Vincent; Dorrestein, Pieter C; Raaijmakers, Jos M; de Bruijn, Irene

    2015-01-01

    Emerging fungal and oomycete pathogens are increasingly threatening animals and plants globally. Amongst oomycetes, Saprolegnia species adversely affect wild and cultivated populations of amphibians and fish, leading to substantial reductions in biodiversity and food productivity. With the ban of several chemical control measures, new sustainable methods are needed to mitigate Saprolegnia infections in aquaculture. Here, PhyloChip-based community analyses showed that the Pseudomonadales, particularly Pseudomonas species, represent one of the largest bacterial orders associated with salmon eggs from a commercial hatchery. Among the Pseudomonas species isolated from salmon eggs, significantly more biosurfactant producers were retrieved from healthy salmon eggs than from Saprolegnia-infected eggs. Subsequent in vivo activity bioassays showed that Pseudomonas isolate H6 significantly reduced salmon egg mortality caused by Saprolegnia diclina. Live colony mass spectrometry showed that strain H6 produces a viscosin-like lipopeptide surfactant. This biosurfactant inhibited growth of Saprolegnia in vitro, but no significant protection of salmon eggs against Saprolegniosis was observed. These results indicate that live inocula of aquatic Pseudomonas strains, instead of their bioactive compound, can provide new (micro)biological and sustainable means to mitigate oomycete diseases in aquaculture.

  1. Screening of different Trichoderma species against agriculturally important foliar plant pathogens.

    PubMed

    Prabhakaran, Narayanasamy; Prameeladevi, Thokala; Sathiyabama, Muthukrishnan; Kamil, Deeba

    2015-01-01

    Different isolates of Trichoderma were isolated from soil samples which were collected from different part of India. These isolates were grouped into four Trichoderma species viz., Trichoderma asperellum (Ta), T. harzianum (Th), T. pseudokoningii (Tp) and T. longibrachiatum (Tl) based on their morphological characters. Identification of the above isolates was also confirmed through ITS region analysis. These Trichoderma isolates were tested for in vitro biological control of Alternaria solani, Bipolaris oryzae, Pyricularia oryzae and Sclerotinia scierotiorum which cause serious diseases like early blight (target spot) of tomato and potato, brown leaf spot disease in rice, rice blast disease, and white mold disease in different plants. Under in vitro conditions, all the four species of Trichoderma (10 isolates) proved 100% potential inhibition against rice blast pathogen Pyracularia oryzae. T. harzianum (Th-01) and T. asperellum (Ta-10) were effective with 86.6% and 97.7%, growth inhibition of B. oryzae, respectively. Among others, T. pseudokoningii (Tp-08) and T. Iongibrachiatum (Tl-09) species were particularly efficient in inhibiting growth of S. sclerotiorum by 97.8% and 93.3%. T. Iongibrachiatum (TI-06 and TI-07) inhibited maximum mycelial growth of A. solani by 87.6% and 84.75. However, all the T. harzianum isolates showed significantly higher inhibition against S. sclerotiorum (CD value 9.430), causing white mold disease. This study led to the selection of potential Trichoderma isolates against rice blast, early blight, brown leaf spot in rice and white mold disease in different crops.

  2. Dual-species transcriptional profiling during systemic candidiasis reveals organ-specific host-pathogen interactions

    PubMed Central

    Hebecker, Betty; Vlaic, Sebastian; Conrad, Theresia; Bauer, Michael; Brunke, Sascha; Kapitan, Mario; Linde, Jörg; Hube, Bernhard; Jacobsen, Ilse D.

    2016-01-01

    Candida albicans is a common cause of life-threatening fungal bloodstream infections. In the murine model of systemic candidiasis, the kidney is the primary target organ while the fungal load declines over time in liver and spleen. To better understand these organ-specific differences in host-pathogen interaction, we performed gene expression profiling of murine kidney, liver and spleen and determined the fungal transcriptome in liver and kidney. We observed a delayed transcriptional immune response accompanied by late induction of fungal stress response genes in the kidneys. In contrast, early upregulation of the proinflammatory response in the liver was associated with a fungal transcriptome resembling response to phagocytosis, suggesting that phagocytes contribute significantly to fungal control in the liver. Notably, C. albicans hypha-associated genes were upregulated in the absence of visible filamentation in the liver, indicating an uncoupling of gene expression and morphology and a morphology-independent effect by hypha-associated genes in this organ. Consistently, integration of host and pathogen transcriptional data in an inter-species gene regulatory network indicated connections of C. albicans cell wall remodelling and metabolism to the organ-specific immune responses. PMID:27808111

  3. Mixed infections, cryptic diversity, and vector-borne pathogens: evidence from Polygenis fleas and Bartonella species.

    PubMed

    Abbot, Patrick; Aviles, Alena E; Eller, Lauren; Durden, Lance A

    2007-10-01

    Coinfections within hosts present opportunities for horizontal gene transfer between strains and competitive interactions between genotypes and thus can be a critical element of the lifestyles of pathogens. Bartonella spp. are Alphaproteobacteria that parasitize mammalian erythrocytes and endothelial cells. Their vectors are thought to be various biting arthropods, such as fleas, ticks, mites, and lice, and they are commonly cited as agents of various emerging diseases. Coinfections by different Bartonella strains and species can be common in mammals, but little is known about specificity and coinfections in arthropod vectors. We surveyed the rate of mixed infections of Bartonella in flea vectors (Polygenis gwyni) parasitizing cotton rats (Sigmodon hispidus) in which previous surveys indicated high rates of infection. We found that nearly all fleas (20 of 21) harbored one or more strains of Bartonella, with rates of coinfection approaching 90%. A strain previously identified as common in cotton rats was also common in their fleas. However, another common strain in cotton rats was absent from P. gwyni, while a rare cotton rat strain was quite common in P. gwyni. Surprisingly, some samples were also coinfected with a strain phylogenetically related to Bartonella clarridgeiae, which is typically associated with felids and ruminants. Finally, a locus (pap31) that is characteristically borne on phage in Bartonella was successfully sequenced from most samples. However, sequence diversity in pap31 was novel in the P. gwyni samples, relative to other Bartonella previously typed with pap31, emphasizing the likelihood of large reservoirs of cryptic diversity in natural populations of the pathogen.

  4. Partitiviruses of a fungal forest pathogen have species-specific quantities of genome segments and transcripts.

    PubMed

    Jurvansuu, Jaana; Kashif, Muhammad; Vaario, Leo; Vainio, Eeva; Hantula, Jarkko

    2014-08-01

    Heterobasidion partitiviruses infect forest pathogenic fungi of the genus Heterobasidion. We have studied the amounts of genomes and transcripts of four partitiviruses isolated from four different Heterobasidion strains infecting different host trees in Greece, Poland, Finland, and China. Heterobasidion partitiviruses have bisegmented genomes encoding coat protein and RNA-dependent RNA polymerase. Our results show that the coat protein genome segment is generally more abundant in infected mycelia than the RNA-dependent RNA polymerase segment and that this bias persists also at transcript levels. The different virus species all have unique ratios of the genome segments and the ratio is generally stable over different temperatures and hosts. The amounts of transcripts of each virus respond to host growth temperatures in a distinctive and consistent manner. The Heterobasidion partitiviruses studied here affect only rarely the growth of their natural hosts but do influence the growth of a new host more frequently.

  5. Multi-locus tree and species tree approaches toward resolving a complex clade of downy mildews (Straminipila, Oomycota), including pathogens of beet and spinach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The family Peronosporaceae (Straminipila; Oomycota) consists of obligate biotrophic pathogens that cause downy mildew disease on angiosperm...

  6. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Staphylococcal typing bacteriophage. (a) Identification. A staphylococcal typing bacteriophage is a...

  7. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Staphylococcal typing bacteriophage. (a) Identification. A staphylococcal typing bacteriophage is a...

  8. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Staphylococcal typing bacteriophage. (a) Identification. A staphylococcal typing bacteriophage is a...

  9. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Staphylococcal typing bacteriophage. (a) Identification. A staphylococcal typing bacteriophage is a...

  10. Discord between morphological and phylogenetic species boundaries: incomplete lineage sorting and recombination results in fuzzy species boundaries in an asexual fungal pathogen

    PubMed Central

    2014-01-01

    Background Traditional morphological and biological species concepts are difficult to apply to closely related, asexual taxa because of the lack of an active sexual phase and paucity of morphological characters. Phylogenetic species concepts such as genealogical concordance phylogenetic species recognition (GCPSR) have been extensively used; however, methods that incorporate gene tree uncertainty into species recognition may more accurately and objectively delineate species. Using a worldwide sample of Alternaria alternata sensu lato, causal agent of citrus brown spot, the evolutionary histories of four nuclear loci including an endo-polygalacturonase gene, two anonymous loci, and one microsatellite flanking region were estimated using the coalescent. Species boundaries were estimated using several approaches including those that incorporate uncertainty in gene genealogies when lineage sorting and non-reciprocal monophyly of gene trees is common. Results Coalescent analyses revealed three phylogenetic lineages strongly influenced by incomplete lineage sorting and recombination. Divergence of the citrus 2 lineage from the citrus 1 and citrus 3 lineages was supported at most loci. A consensus of species tree estimation methods supported two species of Alternaria causing citrus brown spot worldwide. Based on substitution rates at the endo-polygalacturonase locus, divergence of the citrus 2 and the 1 and 3 lineages was estimated to have occurred at least 5, 400 years before present, predating the human-mediated movement of citrus and associated pathogens out of SE Asia. Conclusions The number of Alternaria species identified as causing brown spot of citrus worldwide using morphological criteria has been overestimated. Little support was found for most of these morphospecies using quantitative species recognition approaches. Correct species delimitation of plant-pathogenic fungi is critical for understanding the evolution of pathogenicity, introductions of pathogens to

  11. Rapid Identification of Emerging Human-Pathogenic Sporothrix Species with Rolling Circle Amplification

    PubMed Central

    Rodrigues, Anderson M.; Najafzadeh, Mohammad J.; de Hoog, G. Sybren; de Camargo, Zoilo P.

    2015-01-01

    Sporothrix infections are emerging as an important human and animal threat among otherwise healthy patients, especially in Brazil and China. Correct identification of sporotrichosis agents is beneficial for epidemiological surveillance, enabling implementation of adequate public-health policies and guiding antifungal therapy. In areas of limited resources where sporotrichosis is endemic, high-throughput detection methods that are specific and sensitive are preferred over phenotypic methods that usually result in misidentification of closely related Sporothrix species. We sought to establish rolling circle amplification (RCA) as a low-cost screening tool for species-specific identification of human-pathogenic Sporothrix. We developed six species-specific padlock probes targeting polymorphisms in the gene encoding calmodulin. BLAST-searches revealed candidate probes that were conserved intraspecifically; no significant homology with sequences from humans, mice, plants or microorganisms outside members of Sporothrix were found. The accuracy of our RCA-based assay was demonstrated through the specificity of probe-template binding to 25 S. brasiliensis, 58 S. schenckii, 5 S. globosa, 1 S. luriei, 4 S. mexicana, and 3 S. pallida samples. No cross reactivity between closely related species was evident in vitro, and padlock probes yielded 100% specificity and sensitivity down to 3 × 106 copies of the target sequence. RCA-based speciation matched identifications via phylogenetic analysis of the gene encoding calmodulin and the rDNA operon (kappa 1.0; 95% confidence interval 1.0-1.0), supporting its use as a reliable alternative to DNA sequencing. This method is a powerful tool for rapid identification and specific detection of medically relevant Sporothrix, and due to its robustness has potential for ecological studies. PMID:26696992

  12. Rhodomyrtus tomentosa (Aiton) Hassk. leaf extract: An alternative approach for the treatment of staphylococcal bovine mastitis.

    PubMed

    Mordmuang, Auemphon; Voravuthikunchai, Supayang Piyawan

    2015-10-01

    Antibiotic residues in dairy products as well as emergence of antimicrobial resistance in foodborne pathogens have been recognized as global public health concerns. The present work was aimed to study a potent antibacterial extract from natural product as an alternative treatment for staphylococcal bovine mastitis. Staphylococcal isolates (n=44) were isolated from milk samples freshly squeezed from individual cows. All staphylococcal isolates were resistant to ampicillin, ciprofloxacin, erythromycin, gentamicin, penicillin, except vancomycin. Rhodomyrtus tomentosa leaf ethanolic extract was accessed for its antibacterial activity and anti-inflammatory potential. The extract exhibited profound antibacterial activity against all of staphylococcal isolates with MIC and MBC values ranged from 16-64 μg/ml and 64->128 μg/ml, respectively. Moreover, the extract also exerted anti-protein denaturation and human red blood cell membrane stabilizing activity. The results support the use of R. tomentosa extract that could be applied to cure bovine mastitis and to reduce inflammatory injury caused by the bacterial infections.

  13. Transcriptional Control of Drug Resistance, Virulence and Immune System Evasion in Pathogenic Fungi: A Cross-Species Comparison

    PubMed Central

    Pais, Pedro; Costa, Catarina; Cavalheiro, Mafalda; Romão, Daniela; Teixeira, Miguel C.

    2016-01-01

    Transcription factors are key players in the control of the activation or repression of gene expression programs in response to environmental stimuli. The study of regulatory networks taking place in fungal pathogens is a promising research topic that can help in the fight against these pathogens by targeting specific fungal pathways as a whole, instead of targeting more specific effectors of virulence or drug resistance. This review is focused on the analysis of regulatory networks playing a central role in the referred mechanisms in the human fungal pathogens Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis. Current knowledge on the activity of the transcription factors characterized in each of these pathogenic fungal species will be addressed. Particular focus is given to their mechanisms of activation, regulatory targets and phenotypic outcome. The review further provides an evaluation on the conservation of transcriptional circuits among different fungal pathogens, highlighting the pathways that translate common or divergent traits among these species in what concerns their drug resistance, virulence and host immune evasion features. It becomes evident that the regulation of transcriptional networks is complex and presents significant variations among different fungal pathogens. Only the oxidative stress regulators Yap1 and Skn7 are conserved among all studied species; while some transcription factors, involved in nutrient homeostasis, pH adaptation, drug resistance and morphological switching are present in several, though not all species. Interestingly, in some cases not very homologous transcription factors display orthologous functions, whereas some homologous proteins have diverged in terms of their function in different species. A few cases of species specific transcription factors are also observed. PMID:27812511

  14. [Fusarium species associated with basal rot of garlic in North Central Mexico and its pathogenicity].

    PubMed

    Delgado-Ortiz, Juan C; Ochoa-Fuentes, Yisa M; Cerna-Chávez, Ernesto; Beltrán-Beache, Mariana; Rodríguez-Guerra, Raúl; Aguirre-Uribe, Luis A; Vázquez-Martínez, Otilio

    Garlic in Mexico is one of the most profitable vegetable crops, grown in almost 5,451ha; out of which more than 83% are located in Zacatecas, Guanajuato, Sonora, Puebla, Baja California and Aguascalientes. Blossom-end rot caused by Fusarium spp is widely distributed worldwide and has been a limiting factor in onion and garlic production regions, not only in Mexico but also in other countries. The presence of Fusarium oxysporum has been reported in Guanajuato and Aguascalientes. Fusarium culmorum has been reported in onion cultivars of Morelos; and Fusarium proliferatum, Fusarium verticillioides, Fusarium solani and Fusarium acuminatum have been previously reported in Aguascalientes. The goal of this work was identifying the Fusarium species found in Zacatecas, Guanajuato and Aguascalientes, to assess their pathogenicity. Plants with disease symptoms were collected from hereinabove mentioned States. The samples resulted in the identification of: F. oxysporum, F. proliferatum, F. verticillioides, F. solani and F. acuminatum species; out of which Aguascalientes AGS1A (F. oxysporum), AGS1B (F. oxysporum) and AGSY-10 (F. acuminatum) strains showed higher severity under greenhouse conditions.

  15. Virulence arsenal of the most pathogenic species among the Gram-positive anaerobic cocci, Finegoldia magna.

    PubMed

    Boyanova, Lyudmila; Markovska, Rumyana; Mitov, Ivan

    2016-12-01

    This review focuses on the virulence arsenal of the most pathogenic species among Gram positive anaerobic cocci, Finegoldia magna according to recently published data from 2012 to 2016. Virulence factors like sortase dependent pili and F. magna adhesion factor (FAF) facilitate the start of the infection. Albumin binding protein (PAB) enhances F. magna survival. FAF, subtilisin-like extracellular serine protease (SufA) and superantigen protein L protect the bacteria from factors of innate defense system. SufA, capsule and tissue-destroying enzymes provide a deep penetration or spread of the infections and the protein L is associated with infection severity. Biofilm production results in infection chronification and complicated treatment as well as to persistence of multi-species biofilms. Resistance rates to quinolones (13.0->70%) and clindamycin (0-40.0%) are important, and resistance to penicillins (<4%), chloramphenicol (7.0%) and metronidazole (<7%) has been reported. F. magna should not be overlooked when present in monoinfections or mixed infections in humans.

  16. A cohort study of coagulase negative staphylococcal mastitis in selected dairy herds in Prince Edward Island.

    PubMed Central

    Davidson, T J; Dohoo, I R; Donald, A W; Hariharan, H; Collins, K

    1992-01-01

    The epidemiology and importance of coagulase negative staphylococcal (CNS) mastitis in Prince Edward Island had not been documented. To investigate this, a cohort of 84 cows at seven farms were quarter sampled eight times over a lactation, commencing with samples taken prior to drying off in the previous lactation. Thirteen species of CNS were isolated. The quarter prevalence of CNS mastitis varied from 4.8% to 6.4% in the first five months of lactation and increased to 14.2 to 16.6% in the last four months of lactation. The geometric mean somatic cell counts (SCC) for quarters infected with CNS and uninfected quarters were 90 x 10(3) and 64 x 10(3) respectively (difference significant at p > 0.005). The two month new infection risk of CNS was 9.0% while the two month elimination risk was 74.4%. Infection with CNS did not alter the risk of subsequent infection with Staphylococcus aureus. The results from this project support the classification of CNS as a minor pathogen in mastitis control programs. PMID:1477796

  17. Identification and pathogenicity of Botryosphaeriaceae species associated with coast live oak (Quercus agrifolia) decline in southern California.

    PubMed

    Lynch, Shannon C; Eskalen, Akif; Zambino, Paul J; Mayorquin, Joey S; Wang, Danny H

    2013-01-01

    Symptoms of decline have been observed on dying coast live oak (Quercus agrifolia) trees in areas throughout southern California that are both infested and uninfested by the gold-spotted oak borer (GSOB). The purpose of this study was to identify and assess the pathogenicity of several anamorph species of the Botryosphaeriaceae, including Diplodia corticola, Dothiorella iberica and Diplodia agrifolia sp. nov., that were recovered consistently from symptomatic tissues. Species were identified morphologically and by phylogenetic analyses of the complete sequence of the internal transcribed spacer (ITS) of the rDNA and partial sequences of β-tubulin and elongation factor (EF1-α) genes. Results from morphological assessments and phylogenetic analyses support the erection of a new species closely related to D. mutila, described herein as Diplodia agrifolia sp. nov. Pathogenicity of all species was verified by wound inoculation of 1 y old coast live oak seedlings under controlled conditions. Isolates of D. corticola were the most aggressive tested, and isolates of D. agrifolia were the second most aggressive. Both species caused bleeding symptoms on inoculated seedlings. Seedlings inoculated with D. corticola died within 4 wk, with the pathogen progressing up and down through the xylem in advance of living phloem and moving throughout the taproot in 70% of inoculated seedlings. Colonization and re-isolation was successful for all species. All three fungal species represent newly recorded fungal pathogens of coast live oak in California. Results from the pathogenicity test suggest that these fungi play a role in the decline of coast live oaks throughout southern California.

  18. Staphylococcal disease in Africa: another neglected 'tropical' disease.

    PubMed

    Herrmann, Mathias; Abdullah, Salim; Alabi, Abraham; Alonso, Pedro; Friedrich, Alexander W; Fuhr, Günther; Germann, Anja; Kern, Winfried V; Kremsner, Peter G; Mandomando, Inacio; Mellmann, Alexander C; Pluschke, Gerd; Rieg, Siegbert; Ruffing, Ulla; Schaumburg, Frieder; Tanner, Marcel; Peters, Georg; von Briesen, Hagen; von Eiff, Christof; von Müller, Lutz; Grobusch, Martin P

    2013-01-01

    The term 'neglected tropical diseases' predominantly refers to single-entity, mostly parasitic diseases. However, a considerable morbidity and mortality burden is carried by patients infected with Gram-positive cocci and Gram-negative bacilli that are prevalent all over the world, yet have impact in tropical and developing countries, particularly in children, with much higher incidence rates than those reported from developed countries. Staphylococcus aureus is among these pathogens. The African-German StaphNet consortium uses microbiological characterization of African S. aureus isolates, including identification of virulence factors, alongside the gathering of epidemiological and clinical data in an innovative research network between a European country (Germany) and several African partners. By creating an accessible strain repository and by implementing personnel training and capacity building, this network aims to put staphylococcal disease on the international agenda as a truly neglected condition with a major global impact on public health.

  19. Pathogenicity in six Australian reptile species following experimental inoculation with Bohle iridovirus.

    PubMed

    Ariel, E; Wirth, W; Burgess, G; Scott, J; Owens, L

    2015-08-20

    Ranaviruses are able to infect multiple species of fish, amphibian and reptile, and some strains are capable of interclass transmission. These numerous potential carriers and reservoir species compound efforts to control and contain infections in cultured and wild populations, and a comprehensive knowledge of susceptible species and life stage is necessary to inform such processes. Here we report on the challenge of 6 water-associated reptiles with Bohle iridovirus (BIV) to investigate its potential pathogenicity in common native reptiles of the aquatic and riparian fauna of northern Queensland, Australia. Adult tortoises Elseya latisternum and Emydura krefftii, snakes Boiga irregularis, Dendrelaphis punctulatus and Amphiesma mairii, and yearling crocodiles Crocodylus johnstoni were exposed via intracoelomic inoculation or co-habitation with infected con-specifics, but none were adversely affected by the challenge conditions applied here. Bohle iridovirus was found to be extremely virulent in hatchling tortoises E. latisternum and E. krefftii via intracoelomic challenge, as demonstrated by distinct lesions in multiple organs associated with specific immunohistochemistry staining and a lethal outcome (10/17) of the challenge. Virus was re-isolated from 2/5 E. latisternum, 4/12 E. krefftii and 1/3 brown tree snakes B. irregularis. Focal necrosis, haemorrhage and infiltration of granulocytes were frequently observed histologically in the pancreas, liver and sub-mucosa of the intestine of challenged tortoise hatchlings. Immunohistochemistry demonstrated the presence of ranavirus antigens in the necrotic lesions and in individual cells of the vascular endothelium, the connective tissue and in granulocytes associated with necrosis or present along serosal surfaces. The outcome of this study confirms hatchling tortoises are susceptible to BIV, thereby adding Australian reptiles to the host range of ranaviruses. Additionally, given that BIV was originally isolated from an

  20. Interspecific geographic distribution and variation of the pathogens Nosema bombi and Crithidia species in United States bumble bee populations.

    PubMed

    Cordes, Nils; Huang, Wei-Fone; Strange, James P; Cameron, Sydney A; Griswold, Terry L; Lozier, Jeffrey D; Solter, Leellen F

    2012-02-01

    Several bumble bee (Bombus) species in North America have undergone range reductions and rapid declines in relative abundance. Pathogens have been suggested as causal factors, however, baseline data on pathogen distributions in a large number of bumble bee species have not been available to test this hypothesis. In a nationwide survey of the US, nearly 10,000 specimens of 36 bumble bee species collected at 284 sites were evaluated for the presence and prevalence of two known Bombus pathogens, the microsporidium Nosema bombi and trypanosomes in the genus Crithidia. Prevalence of Crithidia was ≤10% for all host species examined but was recorded from 21% of surveyed sites. Crithidia was isolated from 15 of the 36 Bombus species screened, and were most commonly recovered from Bombus bifarius, Bombus bimaculatus, Bombus impatiens and Bombus mixtus. Nosema bombi was isolated from 22 of the 36 US Bombus species collected. Only one species with more than 50 sampled bees, Bombus appositus, was free of the pathogen; whereas, prevalence was highest in Bombus occidentalis and Bombus pensylvanicus, two species that are reportedly undergoing population declines in North America. A variant of a tetranucleotide repeat in the internal transcribed spacer (ITS) of the N. bombi rRNA gene, thus far not reported from European isolates, was isolated from ten US Bombus hosts, appearing in varying ratios in different host species. Given the genetic similarity of the rRNA gene of N. bombi sampled in Europe and North America to date, the presence of a unique isolate in US bumble could reveal one or more native North American strains and indicate that N. bombi is enzootic across the Holarctic Region, exhibiting some genetic isolation.

  1. Influence of pathogenic bacteria species present in the postpartum bovine uterus on proteome profiles.

    PubMed

    Ledgard, A M; Smolenski, G A; Henderson, H; Lee, R S F

    2015-01-01

    In the first 2-3 weeks after parturition >90% of dairy cows will have some form of uterine infection. Uterine contamination with pathogens, such as Trueperella (formerly Arcanobacterium) pyogenes increases the risk of developing more severe endometritis, which can reduce conception rates. In this study, we compared the uterine proteome of cows infected with Trueperella pyogenes with that of uninfected cows, using 2D gel electrophoresis, and identified annexins A1 and A2 (ANXA1 and ANXA2), apolipoprotein A-1, calprotectin (S100A9), cathelicidin, enolase 1 (ENO1), peptidoglycan recognition protein 1 (PGLYRP1), phosphoglycerate mutase 1 (PGAM1), serine dehydratase (SDS) and serine protease inhibitors (SERPIN) B1, B3 and B4 proteins as differing in abundance in endometritis. Subsequently, levels of ten of these proteins were monitored in uterine samples collected from a herd of lactating, dairy cows at 15 and 42 days post-partum (DPP). The levels were compared with the cytology scores of the samples and the bacterial species isolated from the uterus. Cathelicidin, PGLYRP1, SERPINB1 and S100A9 levels at 15DPP showed strong positive correlations (r=0.78, 0.80, 0.79, and 0.68 respectively; P<0.001) with % of polymorphonuclear neutrophils (PMN). When compared with other bacterial pathogens identified, Streptococcus agalactiae and Truperella pyogenes induced increased expression of the indicator proteins, suggesting that these organisms may adversely affect the subsequent ability of the cow to conceive. Interestingly, there was no difference in the proportion of cows pregnant at 6 and 17 weeks after start of mating between the cows with high or low %PMN.

  2. Efficiency of rep-PCR fingerprinting as a useful technique for molecular typing of plant pathogenic fungal species: Botryosphaeriaceae species as a case study.

    PubMed

    Abdollahzadeh, Jafar; Zolfaghari, Sajedeh

    2014-12-01

    Progress in molecular biology and the advent of rapid and accurate molecular techniques have contributed to precise and rapid detection and differentiation of microbial pathogens. Identification of the Botryosphaeriaceae species based on morphology has been problematic over time. In this study, we used rep-PCR technique as a molecular tool for typing and differentiation of the Botryosphaeriaceae species, well-known and cosmopolitan fungal pathogens on woody plants. Three primer sets BOX, ERIC and REP were used to differentiate 27 species belong to eight genera. The majority of them were examined in terms of typing and differentiation using molecular methods for the first time. All the primer sets were able to generate species-specific DNA fingerprints from all the tested strains, with two exceptions in the genera Diplodia and Spencermartinsia. Despite the deficiency of each primer sets to separate a few species, cluster analysis of combined data sets indicated the ability of rep-PCR technique to separate 26 out of 27 examined species in highly supported clusters corresponded to the species recognized based on DNA sequence data. Our findings revealed the efficiency of rep-PCR for detection and differentiation of the Botryosphaeriaceae species, especially cryptic species with the same ITS sequences and similar morphology.

  3. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks

    PubMed Central

    2013-01-01

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. In this study we examined the pathogenicity of H5N1 HPAI viruses in different species and breeds of domestic ducks and the effect of route of virus inoculation on the outcome of infection. We determined that the pathogenicity of H5N1 HPAI viruses varies between the two common farmed duck species, with Muscovy ducks (Cairina moschata) presenting more severe disease than various breeds of Anas platyrhynchos var. domestica ducks including Pekin, Mallard-type, Black Runners, Rouen, and Khaki Campbell ducks. We also found that Pekin and Muscovy ducks inoculated with two H5N1 HPAI viruses of different virulence, given by any one of three routes (intranasal, intracloacal, or intraocular), became infected with the viruses. Regardless of the route of inoculation, the outcome of infection was similar for each species but depended on the virulence of the virus used. Muscovy ducks showed more severe clinical signs and higher mortality than the Pekin ducks. In conclusion, domestic ducks are susceptible to H5N1 HPAI virus infection by different routes of exposure, but the presentation of the disease varied by virus strain and duck species. This information helps support the planning and implementation of H5N1 HPAI surveillance and control measures in countries with large domestic duck populations. PMID:23876184

  4. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks.

    PubMed

    Pantin-Jackwood, Mary; Swayne, David E; Smith, Diane; Shepherd, Eric

    2013-07-22

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. In this study we examined the pathogenicity of H5N1 HPAI viruses in different species and breeds of domestic ducks and the effect of route of virus inoculation on the outcome of infection. We determined that the pathogenicity of H5N1 HPAI viruses varies between the two common farmed duck species, with Muscovy ducks (Cairina moschata) presenting more severe disease than various breeds of Anas platyrhynchos var. domestica ducks including Pekin, Mallard-type, Black Runners, Rouen, and Khaki Campbell ducks. We also found that Pekin and Muscovy ducks inoculated with two H5N1 HPAI viruses of different virulence, given by any one of three routes (intranasal, intracloacal, or intraocular), became infected with the viruses. Regardless of the route of inoculation, the outcome of infection was similar for each species but depended on the virulence of the virus used. Muscovy ducks showed more severe clinical signs and higher mortality than the Pekin ducks. In conclusion, domestic ducks are susceptible to H5N1 HPAI virus infection by different routes of exposure, but the presentation of the disease varied by virus strain and duck species. This information helps support the planning and implementation of H5N1 HPAI surveillance and control measures in countries with large domestic duck populations.

  5. Tick species, tick-borne pathogens and symbionts in an insular environment off the coast of Western France.

    PubMed

    Michelet, Lorraine; Joncour, Guy; Devillers, Elodie; Torina, Alessandra; Vayssier-Taussat, Muriel; Bonnet, Sarah I; Moutailler, Sara

    2016-10-01

    Insular environments provide ideal natural conditions to study disease ecology, especially emerging diseases, due to clear differentiation between local and long-distance transmission. Such environments are of particular interest regarding tick-borne pathogens (TBP), since animal exchange with the mainland (along with any ticks they carry) is limited, and because such locations could lie on migratory routes for birds carrying ticks. Therefore both tick species and TBP may display different prevalence than those observed on the continent. As such, an epidemiological survey was performed on Belle-Ile-en-Mer, an island off the coast of Western France, in order to estimate the prevalence of tick species and the microorganisms they carried. Three tick species, Dermacentor marginatus, D. reticulatus, and Haemaphysalis punctata were collected at five different sites in 2010 and 2011. All ticks were tested for pathogen's and symbiont's DNA by (i) PCR for Anaplasma spp., Borrelia spp., Rickettsia spp.; (ii) real-time PCR for Francisella tularensis, Francisella-like endosymbionts (FLE) and Coxiella spp. and (iii) PCR-RLB for Babesia-Theileria spp. Pathogen DNA detected in D. marginatus including Borrelia spp. (18%), Rickettsia spp. (13%) which was identified as R. slovaca, Babesia spp. (8%), and Theileria spp. (1%). Pathogens detected in D. reticulatus including Rickettsia spp. (31%) identified as R. raoulti, Francisella-like endosymbiont (86%), and Babesia spp (21%). Pathogens detected in H. punctata including Rickettsia spp. (1%) identified as R. aeschlimannii, FLE (0.4%), Babesia spp. (18%), and Theileria spp. (7%). Anaplasma spp., F. tularensis, or Coxiella spp. were not detected in any of the collected ticks. This study represents the first epidemiological survey of the insular Belle-Ile-en-Mer environment. It demonstrated the presence of expected pathogens, consistent with reports from island veterinarians or physicians, as well as unexpected pathogens, raising

  6. Rabbit hepatitis E virus is an opportunistic pathogen in specific-pathogen-free rabbits with the capability of cross-species transmission.

    PubMed

    Liu, Baoyuan; Sun, Yani; Du, Taofeng; Chen, Yiyang; Wang, Xinjie; Huang, Baicheng; Li, Huixia; Nan, Yuchen; Xiao, Shuqi; Zhang, Gaiping; Hiscox, Julian A; Zhou, En-Min; Zhao, Qin

    2017-03-01

    Hepatitis E virus (HEV) has been detected in rabbits, a recently identified natural reservoir. In this study, anti-HEV antibodies and viral RNA were detected in rabbits sourced from a specific-pathogen-free (SPF) rabbit vendor in Shaanxi Province, China. BLAST results of partial HEV ORF2 genes cloned here indicated that two viral strains circulated in the rabbits. Sequence determination of the complete genome (7302bp) of one strain and a partial ORF1 gene (1537bp) of the other strain showed that they shared 90% identity with one another and 78%-94% identity with other known rabbit HEVs. In addition, inoculation with rabbit HEV from SPF rabbits studied here resulted in infection of SPF pigs; this cross-species transmission was evidenced by seroconversion, viremia and faecal virus shedding. These results suggest that to prevent spread of this zoonotic pathogen, rabbits should be tested routinely for HEV RNA in SPF vendor facilities.

  7. Impact of larval pathogen infection on conspecific oviposition preference of three medically important mosquito species of Florida.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oviposition responses of three medically important mosquito species were evaluated in two-choice bioassays to determine if larval pathogen infection affected oviposition site choice. Both Aedes aegypti and Ae. albopictus laid significantly fewer eggs in cups containing infected larvae, however, Cule...

  8. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species

    PubMed Central

    Baroncelli, Riccardo; Zapparata, Antonio; Sarrocco, Sabrina; Sukno, Serenella A.; Lane, Charles R.; Thon, Michael R.; Vannacci, Giovanni; Holub, Eric; Sreenivasaprasad, Surapareddy

    2015-01-01

    Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production. PMID:26086351

  9. Analysis of phylogeny, distribution, and pathogenicity of Botryosphaeriaceae species associated with gummosis of Anacardium in Brazil, with a new species of Lasiodiplodia.

    PubMed

    Netto, Mariote S B; Lima, Waléria G; Correia, Kamila C; da Silva, Christiana F B; Thon, Michael; Martins, Ricardo B; Miller, Robert N G; Michereff, Sami J; Câmara, Marcos P S

    2017-04-01

    Netto, M. S. B., Lima, W. G., Correia, K. C., da Silva, C. F. B., Thon, M., Martins, R. B., Miller, R. N. G., Michereff, S. J., and Câmara, M. P. S. 2016. Analysis of phylogeny, distribution, and pathogenicity of Botryosphaeriaceae species associated with gummosis of Anacardium in Brazil, with a new species of Lasiodiplodia. We identified Botryosphaeriaceae species associated with gummosis on Anacardium in Brazil. Isolates were sampled and identified on the basis morphology and phylogeny, through analysis of a partial translation elongation factor 1-α sequence, ribosomal DNA internal transcribed spacers, and β-tubulin gene sequence. Ten taxa were identified, namely, Lasiodiplodia brasiliense, L. euphorbicola, L. gonubiensis, L. iraniensis, L. jatrophicola, L. gravistriata sp. nov., L. pseudotheobromae, L. theobromae, Neofusicoccum batangarum, and Pseudofusicoccum stromaticum. Lasiodiplodia theobromae has been previously reported in cashew and is the most prevalent species observed. All the other species are reported here for the first time on this host. All species of Botryosphaeriaceae were pathogenic on detached green cashew shoots. Differences in aggressiveness were observed among the species, with N. batangarum, L. iraniensis, L. jatrophicola, and L. gravistriata characterized as the most aggressive species, whilst L. euphorbicola and L. pseudotheobromae were identified as the least aggressive.

  10. River Networks As Ecological Corridors for Species, Populations and Pathogens of Water-Borne Disease

    NASA Astrophysics Data System (ADS)

    Rinaldo, A.

    2014-12-01

    River basins are a natural laboratory for the study of the integration of hydrological, ecological and geomorphological processes. Moving from morphological and functional analyses of dendritic geometries observed in Nature over a wide range of scales, this Lecture addresses essential ecological processes that take place along dendritic structures, hydrology-driven and controlled, like e.g.: population migrations and human settlements, that historically proceeded along river networks to follow water supply routes; riparian ecosystems composition that owing to their positioning along streams play crucial roles in their watersheds and in the loss of biodiversity proceeding at unprecedented rates; waterborne disease spreading, like epidemic cholera that exhibits epidemic patterns that mirror those of watercourses and of human mobility and resurgences upon heavy rainfall. Moreover, the regional incidence of Schistosomiasis, a parasitic waterborne disease, and water resources developments prove tightly related, and proliferative kidney disease in fish thrives differently in pristine and engineered watercourses: can we establish quantitatively the critical linkages with hydrologic drivers and controls? How does connectivity within a river network affect community composition or the spreading mechanisms? Does the river basin act as a template for biodiversity or for species' persistence? Are there hydrologic controls on epidemics of water-borne disease? Here, I shall focus on the noteworthy scientific perspectives provided by spatially explicit eco-hydrological studies centered on river networks viewed as ecological corridors for species, populations and pathogens of waterborne disease. A notable methodological coherence is granted by the mathematical description of river networks as the support for reactive transport. The Lecture overviews a number of topics idiosyncratically related to my own research work but ideally aimed at a coherent body of materials and methods. A

  11. PATRIC: the Comprehensive Bacterial Bioinformatics Resource with a Focus on Human Pathogenic Species ▿ ‡ #

    PubMed Central

    Gillespie, Joseph J.; Wattam, Alice R.; Cammer, Stephen A.; Gabbard, Joseph L.; Shukla, Maulik P.; Dalay, Oral; Driscoll, Timothy; Hix, Deborah; Mane, Shrinivasrao P.; Mao, Chunhong; Nordberg, Eric K.; Scott, Mark; Schulman, Julie R.; Snyder, Eric E.; Sullivan, Daniel E.; Wang, Chunxia; Warren, Andrew; Williams, Kelly P.; Xue, Tian; Seung Yoo, Hyun; Zhang, Chengdong; Zhang, Yan; Will, Rebecca; Kenyon, Ronald W.; Sobral, Bruno W.

    2011-01-01

    Funded by the National Institute of Allergy and Infectious Diseases, the Pathosystems Resource Integration Center (PATRIC) is a genomics-centric relational database and bioinformatics resource designed to assist scientists in infectious-disease research. Specifically, PATRIC provides scientists with (i) a comprehensive bacterial genomics database, (ii) a plethora of associated data relevant to genomic analysis, and (iii) an extensive suite of computational tools and platforms for bioinformatics analysis. While the primary aim of PATRIC is to advance the knowledge underlying the biology of human pathogens, all publicly available genome-scale data for bacteria are compiled and continually updated, thereby enabling comparative analyses to reveal the basis for differences between infectious free-living and commensal species. Herein we summarize the major features available at PATRIC, dividing the resources into two major categories: (i) organisms, genomes, and comparative genomics and (ii) recurrent integration of community-derived associated data. Additionally, we present two experimental designs typical of bacterial genomics research and report on the execution of both projects using only PATRIC data and tools. These applications encompass a broad range of the data and analysis tools available, illustrating practical uses of PATRIC for the biologist. Finally, a summary of PATRIC's outreach activities, collaborative endeavors, and future research directions is provided. PMID:21896772

  12. PHI-base: a new interface and further additions for the multi-species pathogen-host interactions database.

    PubMed

    Urban, Martin; Cuzick, Alayne; Rutherford, Kim; Irvine, Alistair; Pedro, Helder; Pant, Rashmi; Sadanadan, Vidyendra; Khamari, Lokanath; Billal, Santoshkumar; Mohanty, Sagar; Hammond-Kosack, Kim E

    2017-01-04

    The pathogen-host interactions database (PHI-base) is available at www.phi-base.org PHI-base contains expertly curated molecular and biological information on genes proven to affect the outcome of pathogen-host interactions reported in peer reviewed research articles. In addition, literature that indicates specific gene alterations that did not affect the disease interaction phenotype are curated to provide complete datasets for comparative purposes. Viruses are not included. Here we describe a revised PHI-base Version 4 data platform with improved search, filtering and extended data display functions. A PHIB-BLAST search function is provided and a link to PHI-Canto, a tool for authors to directly curate their own published data into PHI-base. The new release of PHI-base Version 4.2 (October 2016) has an increased data content containing information from 2219 manually curated references. The data provide information on 4460 genes from 264 pathogens tested on 176 hosts in 8046 interactions. Prokaryotic and eukaryotic pathogens are represented in almost equal numbers. Host species belong ∼70% to plants and 30% to other species of medical and/or environmental importance. Additional data types included into PHI-base 4 are the direct targets of pathogen effector proteins in experimental and natural host organisms. The curation problems encountered and the future directions of the PHI-base project are briefly discussed.

  13. Genome Content and Phylogenomics Reveal both Ancestral and Lateral Evolutionary Pathways in Plant-Pathogenic Streptomyces Species.

    PubMed

    Huguet-Tapia, Jose C; Lefebure, Tristan; Badger, Jonathan H; Guan, Dongli; Pettis, Gregg S; Stanhope, Michael J; Loria, Rosemary

    2016-01-29

    Streptomyces spp. are highly differentiated actinomycetes with large, linear chromosomes that encode an arsenal of biologically active molecules and catabolic enzymes. Members of this genus are well equipped for life in nutrient-limited environments and are common soil saprophytes. Out of the hundreds of species in the genus Streptomyces, a small group has evolved the ability to infect plants. The recent availability of Streptomyces genome sequences, including four genomes of pathogenic species, provided an opportunity to characterize the gene content specific to these pathogens and to study phylogenetic relationships among them. Genome sequencing, comparative genomics, and phylogenetic analysis enabled us to discriminate pathogenic from saprophytic Streptomyces strains; moreover, we calculated that the pathogen-specific genome contains 4,662 orthologs. Phylogenetic reconstruction suggested that Streptomyces scabies and S. ipomoeae share an ancestor but that their biosynthetic clusters encoding the required virulence factor thaxtomin have diverged. In contrast, S. turgidiscabies and S. acidiscabies, two relatively unrelated pathogens, possess highly similar thaxtomin biosynthesis clusters, which suggests that the acquisition of these genes was through lateral gene transfer.

  14. Genome Content and Phylogenomics Reveal both Ancestral and Lateral Evolutionary Pathways in Plant-Pathogenic Streptomyces Species

    PubMed Central

    Huguet-Tapia, Jose C.; Lefebure, Tristan; Badger, Jonathan H.; Guan, Dongli; Stanhope, Michael J.

    2016-01-01

    Streptomyces spp. are highly differentiated actinomycetes with large, linear chromosomes that encode an arsenal of biologically active molecules and catabolic enzymes. Members of this genus are well equipped for life in nutrient-limited environments and are common soil saprophytes. Out of the hundreds of species in the genus Streptomyces, a small group has evolved the ability to infect plants. The recent availability of Streptomyces genome sequences, including four genomes of pathogenic species, provided an opportunity to characterize the gene content specific to these pathogens and to study phylogenetic relationships among them. Genome sequencing, comparative genomics, and phylogenetic analysis enabled us to discriminate pathogenic from saprophytic Streptomyces strains; moreover, we calculated that the pathogen-specific genome contains 4,662 orthologs. Phylogenetic reconstruction suggested that Streptomyces scabies and S. ipomoeae share an ancestor but that their biosynthetic clusters encoding the required virulence factor thaxtomin have diverged. In contrast, S. turgidiscabies and S. acidiscabies, two relatively unrelated pathogens, possess highly similar thaxtomin biosynthesis clusters, which suggests that the acquisition of these genes was through lateral gene transfer. PMID:26826232

  15. Impact of Environmental Cues on Staphylococcal Quorum Sensing and Biofilm Development.

    PubMed

    Kavanaugh, Jeffrey S; Horswill, Alexander R

    2016-06-10

    Staphylococci are commensal bacteria that colonize the epithelial surfaces of humans and many other mammals. These bacteria can also attach to implanted medical devices and develop surface-associated biofilm communities that resist clearance by host defenses and available chemotherapies. These communities are often associated with persistent staphylococcal infections that place a tremendous burden on the healthcare system. Understanding the regulatory program that controls staphylococcal biofilm development, as well as the environmental conditions that modulate this program, has been a focal point of research in recent years. A central regulator controlling biofilm development is a peptide quorum-sensing system, also called the accessory gene regulator or agr system. In the opportunistic pathogen Staphylococcus aureus, the agr system controls production of exo-toxins and exo-enzymes essential for causing infections, and simultaneously, it modulates the ability of this pathogen to attach to surfaces and develop a biofilm, or to disperse from the biofilm state. In this review, we explore advances on the interconnections between the agr quorum-sensing system and biofilm mechanisms, and topics covered include recent findings on how different environmental conditions influence quorum sensing, the impact on biofilm development, and ongoing questions and challenges in the field. As our understanding of the quorum sensing and biofilm interconnection advances, there are growing opportunities to take advantage of this knowledge and develop therapeutic approaches to control staphylococcal infections.

  16. Isolation and Characterization of Plant-Pathogenic Streptomyces Species Associated with Common Scab-Infected Potato Tubers in Newfoundland.

    PubMed

    Fyans, Joanna K; Bown, Luke; Bignell, Dawn R D

    2016-02-01

    Potato common scab (CS) is an economically important crop disease that is caused by several members of the genus Streptomyces. In this study, we characterized the plant-pathogenic Streptomyces spp. associated with CS-infected potato tubers harvested in Newfoundland, Canada. A total of 17 pathogenic Streptomyces isolates were recovered from potato scab lesions, of which eight were determined to be most similar to the known CS pathogen S. europaeiscabiei. All eight S. europaeiscabiei isolates were found to produce the thaxtomin A phytotoxin and to harbor the nec1 virulence gene, and most also carry the putative virulence gene tomA. The remaining isolates appear to be novel pathogenic species that do not produce thaxtomin A, and only two of these isolates were determined to harbor the nec1 or tomA genes. Of the non-thaxtomin-producing isolates, strain 11-1-2 was shown to exhibit a severe pathogenic phenotype against different plant hosts and to produce a novel, secreted phytotoxic substance. This is the first report documenting the plant-pathogenic Streptomyces spp. associated with CS disease in Newfoundland. Furthermore, our findings provide further evidence that phytotoxins other than thaxtomin A may also contribute to the development of CS by Streptomyces spp.

  17. Fusarium foetens, a new species pathogenic to begonia elatior hybrids (Begonia x hiemalis) and the sister taxon of the Fusarium oxysporum species complex.

    PubMed

    Schroers, H-J; Baayen, R P; Meffert, J P; de Gruyter, J; Hooftman, M; O'Donnell, K

    2004-01-01

    A new disease recently was discovered in begonia elatior hybrid (Begonia × hiemalis) nurseries in The Netherlands. Diseased plants showed a combination of basal rot, vein yellowing and wilting and the base of collapsing plants was covered by unusually large masses of Fusarium macroconidia. A species of Fusarium was isolated consistently from the discolored veins of leaves and stems. It differed morphologically from F. begoniae, a known agent of begonia flower, leaf and stem blight. The Fusarium species resembled members of the F. oxysporum species complex in producing short monophialides on the aerial mycelium and abundant chlamydospores. Other phenotypic characters such as polyphialides formed occasionally in at least some strains, relatively long monophialides intermingled with the short monophialides formed on the aerial mycelium, distinct sporodochial conidiomata, and distinct pungent colony odor distinguished it from the F. oxysporum species complex. Phylogenetic analyses of partial sequences of the mitochondrial small subunit of the ribosomal DNA (mtSSU rDNA), nuclear translation elongation factor 1α (EF-1α) and β-tubulin gene exons and introns indicate that the Fusarium species represents a sister group of the F. oxysporum species complex. Begonia × hiemalis cultivars Bazan, Bellona and Netja Dark proved to be highly susceptible to the new species. Inoculated plants developed tracheomycosis within 4 wk, and most died within 8 wk. The new taxon was not pathogenic to Euphorbia pulcherrima, Impatiens walleriana and Saintpaulia ionantha that commonly are grown in nurseries along with B. × hiemalis. Inoculated plants of Cyclamen persicum did not develop the disease but had discolored vessels from which the inoculated fungus was isolated. Given that the newly discovered begonia pathogen is distinct in pathogenicity, morphology and phylogeny from other fusaria, it is described here as a new species, Fusarium foetens.

  18. The Presence of Two Receptor-Binding Proteins Contributes to the Wide Host Range of Staphylococcal Twort-Like Phages

    PubMed Central

    Takeuchi, Ippei; Osada, Keita; Azam, Aa Haeruman; Asakawa, Hiroaki; Miyanaga, Kazuhiko

    2016-01-01

    ABSTRACT Thanks to their wide host range and virulence, staphylococcal bacteriophages (phages) belonging to the genus Twortlikevirus (staphylococcal Twort-like phages) are regarded as ideal candidates for clinical application for Staphylococcus aureus infections due to the emergence of antibiotic-resistant bacteria of this species. To increase the usability of these phages, it is necessary to understand the mechanism underlying host recognition, especially the receptor-binding proteins (RBPs) that determine host range. In this study, we found that the staphylococcal Twort-like phage ΦSA012 possesses at least two RBPs. Genomic analysis of five mutant phages of ΦSA012 revealed point mutations in orf103, in a region unique to staphylococcal Twort-like phages. Phages harboring mutated ORF103 could not infect S. aureus strains in which wall teichoic acids (WTAs) are glycosylated with α-N-acetylglucosamine (α-GlcNAc). A polyclonal antibody against ORF103 also inhibited infection by ΦSA012 in the presence of α-GlcNAc, suggesting that ORF103 binds to α-GlcNAc. In contrast, a polyclonal antibody against ORF105, a short tail fiber component previously shown to be an RBP, inhibited phage infection irrespective of the presence of α-GlcNAc. Immunoelectron microscopy indicated that ORF103 is a tail fiber component localized at the bottom of the baseplate. From these results, we conclude that ORF103 binds α-GlcNAc in WTAs, whereas ORF105, the primary RBP, is likely to bind the WTA backbone. These findings provide insight into the infection mechanism of staphylococcal Twort-like phages. IMPORTANCE Staphylococcus phages belonging to the genus Twortlikevirus (called staphylococcal Twort-like phages) are considered promising agents for control of Staphylococcus aureus due to their wide host range and highly lytic capabilities. Although staphylococcal Twort-like phages have been studied widely for therapeutic purposes, the host recognition process of staphylococcal Twort

  19. E. coli bacteremia in comparison to K. pneumoniae bacteremia: influence of pathogen species and ESBL production on 7-day mortality.

    PubMed

    Leistner, R; Bloch, A; Gastmeier, P; Schwab, F

    2016-01-01

    In a previous study, we demonstrated prolonged length of hospital stay in cases of extended-spectrum beta-lactamase (ESBL)-positive K. pneumoniae bacteremia compared to bacteremia cases due to E. coli (ESBL-positive and -negative) and ESBL-negative K. pneumoniae. The overall mortality was significantly higher in bacteremia cases resulting from ESBL-positive pathogens but also in K. pneumoniae cases disregarding ESBL-production. In order to examine whether pathogen species rather than multidrug resistance might affect mortality risk, we reanalyzed our dataset that includes 1.851 cases of bacteremia.

  20. Distribution and Diversity of Pathogenic Leptospira Species in Peri-domestic Surface Waters from South Central Chile

    PubMed Central

    Mason, Meghan R.; Encina, Carolina; Sreevatsan, Srinand; Muñoz-Zanzi, Claudia

    2016-01-01

    Background Leptospirosis is a neglected zoonosis affecting animals and humans caused by infection with Leptospira. The bacteria can survive outside of hosts for long periods of time in soil and water. While identification of Leptospira species from human cases and animal reservoirs are increasingly reported, little is known about the diversity of pathogenic Leptospira species in the environment and how surveillance of the environment might be used for monitoring and controlling disease. Methods and Findings Water samples (n = 104) were collected from the peri-domestic environment of 422 households from farms, rural villages, and urban slums participating in a broader study on the eco-epidemiology of leptospirosis in the Los Rios Region, Chile, between October 2010 and April 2012. The secY region of samples, previously detected as pathogenic Leptospira by PCR, was amplified and sequenced. Sequences were aligned using ClustalW in MEGA, and a minimum spanning tree was created in PHYLOViZ using the goeBURST algorithm to assess sequence similarity. Sequences from four clinical isolates, 17 rodents, and 20 reference strains were also included in the analysis. Overall, water samples contained L. interrogans, L. kirschneri, and L. weilii, with descending frequency. All species were found in each community type. The distribution of the species differed by the season in which the water samples were obtained. There was no evidence that community-level prevalence of Leptospira in dogs, rodents, or livestock influenced pathogen diversity in the water samples. Conclusions This study reports the presence of pathogenic Leptospira in the peri-domestic environment of households in three community types and the differences in Leptospira diversity at the community level. Systematic environmental surveillance of Leptospira can be used for detecting changes in pathogen diversity and to identify and monitor contaminated areas where an increased risk of human infection exists. PMID

  1. Generation of reactive oxygen species via NOXa is important for development and pathogenicity of mycosphaerella graminicola

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ascomycete fungus Mycosphaerella graminicola is an important pathogen of wheat causing economically significant losses. The primary nutritional mode of this fungus is thought to be hemibiotrophic. This pathogenic lifestyle is associated with an early biotrophic stage of nutrient uptake followed ...

  2. Antifungal Activity of Lactic Acid Bacteria Strains Isolated from Natural Honey against Pathogenic Candida Species

    PubMed Central

    Bulgasem, Bulgasem Y.; Lani, Mohd Nizam; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G.

    2016-01-01

    The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly (p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly (p < 0.05) effective against C. krusei, C. glabrata, and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species. PMID:28154488

  3. Antifungal Activity of Lactic Acid Bacteria Strains Isolated from Natural Honey against Pathogenic Candida Species.

    PubMed

    Bulgasem, Bulgasem Y; Lani, Mohd Nizam; Hassan, Zaiton; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G

    2016-12-01

    The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly (p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly (p < 0.05) effective against C. krusei, C. glabrata, and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species.

  4. Species- and Strain-Specific Adaptation of the HSP70 Super Family in Pathogenic Trypanosomatids.

    PubMed

    Drini, Sima; Criscuolo, Alexis; Lechat, Pierre; Imamura, Hideo; Skalický, Tomáš; Rachidi, Najma; Lukeš, Julius; Dujardin, Jean-Claude; Späth, Gerald F

    2016-07-02

    All eukaryotic genomes encode multiple members of the heat shock protein 70 (HSP70) family, which evolved distinctive structural and functional features in response to specific environmental constraints. Phylogenetic analysis of this protein family thus can inform on genetic and molecular mechanisms that drive species-specific environmental adaptation. Here we use the eukaryotic pathogen Leishmania spp. as a model system to investigate the evolution of the HSP70 protein family in an early-branching eukaryote that is prone to gene amplification and adapts to cytotoxic host environments by stress-induced and chaperone-dependent stage differentiation. Combining phylogenetic and comparative analyses of trypanosomatid genomes, draft genome of Paratrypanosoma and recently published genome sequences of 204 L. donovani field isolates, we gained unique insight into the evolutionary dynamics of the Leishmania HSP70 protein family. We provide evidence for (i) significant evolutionary expansion of this protein family in Leishmania through gene amplification and functional specialization of highly conserved canonical HSP70 members, (ii) evolution of trypanosomatid-specific, non-canonical family members that likely gained ATPase-independent functions, and (iii) loss of one atypical HSP70 member in the Trypanosoma genus. Finally, we reveal considerable copy number variation of canonical cytoplasmic HSP70 in highly related L. donovani field isolates, thus identifying this locus as a potential hot spot of environment-genotype interaction. Our data draw a complex picture of the genetic history of HSP70 in trypanosomatids that is driven by the remarkable plasticity of the Leishmania genome to undergo massive intra-chromosomal gene amplification to compensate for the absence of regulated transcriptional control in these parasites.

  5. Species- and Strain-Specific Adaptation of the HSP70 Super Family in Pathogenic Trypanosomatids

    PubMed Central

    Drini, Sima; Criscuolo, Alexis; Lechat, Pierre; Imamura, Hideo; Skalický, Tomáš; Rachidi, Najma; Lukeš, Julius; Dujardin, Jean-Claude; Späth, Gerald F.

    2016-01-01

    All eukaryotic genomes encode multiple members of the heat shock protein 70 (HSP70) family, which evolved distinctive structural and functional features in response to specific environmental constraints. Phylogenetic analysis of this protein family thus can inform on genetic and molecular mechanisms that drive species-specific environmental adaptation. Here we use the eukaryotic pathogen Leishmania spp. as a model system to investigate the evolution of the HSP70 protein family in an early-branching eukaryote that is prone to gene amplification and adapts to cytotoxic host environments by stress-induced and chaperone-dependent stage differentiation. Combining phylogenetic and comparative analyses of trypanosomatid genomes, draft genome of Paratrypanosoma and recently published genome sequences of 204 L. donovani field isolates, we gained unique insight into the evolutionary dynamics of the Leishmania HSP70 protein family. We provide evidence for (i) significant evolutionary expansion of this protein family in Leishmania through gene amplification and functional specialization of highly conserved canonical HSP70 members, (ii) evolution of trypanosomatid-specific, non-canonical family members that likely gained ATPase-independent functions, and (iii) loss of one atypical HSP70 member in the Trypanosoma genus. Finally, we reveal considerable copy number variation of canonical cytoplasmic HSP70 in highly related L. donovani field isolates, thus identifying this locus as a potential hot spot of environment–genotype interaction. Our data draw a complex picture of the genetic history of HSP70 in trypanosomatids that is driven by the remarkable plasticity of the Leishmania genome to undergo massive intra-chromosomal gene amplification to compensate for the absence of regulated transcriptional control in these parasites. PMID:27371955

  6. Antimicrobials for staphylococcal pathogens that are refractory to resistance development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteriophages are viruses exclusively infecting bacteria and therefore offer suitable tools for their detection and control. At the end of their multiplication cycle, most phages lyse their hosts from within by means of an endolysin (peptidoglycan hydrolase), thereby enabling release of the phage p...

  7. Homology analysis of pathogenic Yersinia species Yersinia enterocolitica, Yersinia pseudotuberculosis, and Yersinia pestis based on multilocus sequence typing.

    PubMed

    Duan, Ran; Liang, Junrong; Shi, Guoxiang; Cui, Zhigang; Hai, Rong; Wang, Peng; Xiao, Yuchun; Li, Kewei; Qiu, Haiyan; Gu, Wenpeng; Du, Xiaoli; Jing, Huaiqi; Wang, Xin

    2014-01-01

    We developed a multilocus sequence typing (MLST) scheme and used it to study the population structure and evolutionary relationships of three pathogenic Yersinia species. MLST of these three Yersinia species showed a complex of two clusters, one composed of Yersinia pseudotuberculosis and Yersinia pestis and the other composed of Yersinia enterocolitica. Within the first cluster, the predominant Y. pestis sequence type 90 (ST90) was linked to Y. pseudotuberculosis ST43 by one locus difference, and 81.25% of the ST43 strains were from serotype O:1b, supporting the hypothesis that Y. pestis descended from the O:1b serotype of Y. pseudotuberculosis. We also found that the worldwide-prevalent serotypes O:1a, O:1b, and O:3 were predominated by specific STs. The second cluster consisted of pathogenic and nonpathogenic Y. enterocolitica strains, two of which may not have identical STs. The pathogenic Y. enterocolitica strains formed a relatively conserved group; most strains clustered within ST186 and ST187. Serotypes O:3, O:8, and O:9 were separated into three distinct blocks. Nonpathogenic Y. enterocolitica STs were more heterogeneous, reflecting genetic diversity through evolution. By providing a better and effective MLST procedure for use with the Yersinia community, valuable information and insights into the genetic evolutionary differences of these pathogens were obtained.

  8. DETECTION AND IDENTIFICATION OF PATHOGENIC CANDIDA SPECIES IN WATER USING FLOW CYTOMETRY COUPLED WITH TAQMAN PCR

    EPA Science Inventory

    As the incidence of human fungal infection increases, the ability to detect and identify pathogenic fungi in potential environmental reservoirs becomes increasingly important for disease control. PCR based assays are widely used for diagnostic purposes, but may be inadequate for...

  9. Natural variation in the Pto pathogen resistance gene within species of wild tomato (Lycopersicon). I. Functional analysis of Pto alleles.

    PubMed

    Rose, Laura E; Langley, Charles H; Bernal, Adriana J; Michelmore, Richard W

    2005-09-01

    Disease resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) in the cultivated tomato, Lycopersicon esculentum, and the closely related L. pimpinellifolium is triggered by the physical interaction between plant disease resistance protein, Pto, and the pathogen avirulence protein, AvrPto. To investigate the extent to which variation in the Pto gene is responsible for naturally occurring variation in resistance to Pst, we determined the resistance phenotype of 51 accessions from seven species of Lycopersicon to isogenic strains of Pst differing in the presence of avrPto. One-third of the plants displayed resistance specifically when the pathogen expressed AvrPto, consistent with a gene-for-gene interaction. To test whether this resistance in these species was conferred specifically by the Pto gene, alleles of Pto were amplified and sequenced from 49 individuals and a subset (16) of these alleles was tested in planta using Agrobacterium-mediated transient assays. Eleven alleles conferred a hypersensitive resistance response (HR) in the presence of AvrPto, while 5 did not. Ten amino acid substitutions associated with the absence of AvrPto recognition and HR were identified, none of which had been identified in previous structure-function studies. Additionally, 3 alleles encoding putative pseudogenes of Pto were isolated from two species of Lycopersicon. Therefore, a large proportion, but not all, of the natural variation in the reaction to strains of Pst expressing AvrPto can be attributed to sequence variation in the Pto gene.

  10. Natural Variation in the Pto Pathogen Resistance Gene Within Species of Wild Tomato (Lycopersicon). I. Functional Analysis of Pto Alleles

    PubMed Central

    Rose, Laura E.; Langley, Charles H.; Bernal, Adriana J.; Michelmore, Richard W.

    2005-01-01

    Disease resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) in the cultivated tomato, Lycopersicon esculentum, and the closely related L. pimpinellifolium is triggered by the physical interaction between plant disease resistance protein, Pto, and the pathogen avirulence protein, AvrPto. To investigate the extent to which variation in the Pto gene is responsible for naturally occurring variation in resistance to Pst, we determined the resistance phenotype of 51 accessions from seven species of Lycopersicon to isogenic strains of Pst differing in the presence of avrPto. One-third of the plants displayed resistance specifically when the pathogen expressed AvrPto, consistent with a gene-for-gene interaction. To test whether this resistance in these species was conferred specifically by the Pto gene, alleles of Pto were amplified and sequenced from 49 individuals and a subset (16) of these alleles was tested in planta using Agrobacterium-mediated transient assays. Eleven alleles conferred a hypersensitive resistance response (HR) in the presence of AvrPto, while 5 did not. Ten amino acid substitutions associated with the absence of AvrPto recognition and HR were identified, none of which had been identified in previous structure-function studies. Additionally, 3 alleles encoding putative pseudogenes of Pto were isolated from two species of Lycopersicon. Therefore, a large proportion, but not all, of the natural variation in the reaction to strains of Pst expressing AvrPto can be attributed to sequence variation in the Pto gene. PMID:15944360

  11. Isolation and characterization of soil Streptomyces species as potential biological control agents against fungal plant pathogens.

    PubMed

    Evangelista-Martínez, Zahaed

    2014-05-01

    The use of antagonist microorganisms against fungal plant pathogens is an attractive and ecologically alternative to the use of chemical pesticides. Streptomyces are beneficial soil bacteria and potential candidates for biocontrol agents. This study reports the isolation, characterization and antagonist activity of soil streptomycetes from the Los Petenes Biosphere Reserve, a Natural protected area in Campeche, Mexico. The results showed morphological, physiological and biochemical characterization of six actinomycetes and their inhibitory activity against Curvularia sp., Aspergillus niger, Helminthosporium sp. and Fusarium sp. One isolate, identified as Streptomyces sp. CACIS-1.16CA showed the potential to inhibit additional pathogens as Alternaria sp., Phytophthora capsici, Colletotrichum sp. and Rhizoctonia sp. with percentages ranging from 47 to 90 %. This study identified a streptomycete strain with a broad antagonist activity that could be used for biocontrol of plant pathogenic fungi.

  12. Staphylococcal phage 2638a endolysin is lytic for Staphylococcus aureus and harbors an inter-lytic-domain cryptic translational start site.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Staphylococcus aureus, a notorious pathogen with a propensity for developing resistance to virtually all antibiotics. Staphylococcal phage 2638A endolysin is a peptidoglycan hydrolase that is lytic for Staphylococcus aureus when exposed externally, making it a new candidate antimicrobial. It sha...

  13. Reactive oxygen species drive evolution of pro-biofilm variants in pathogens by modulating cyclic-di-GMP levels

    PubMed Central

    Ding, Yichen; Liu, Yang; Cai, Zhao; Zhou, Jianuan; Swarup, Sanjay; Drautz-Moses, Daniela I.; Schuster, Stephan Christoph; Kjelleberg, Staffan; Givskov, Michael; Yang, Liang

    2016-01-01

    The host immune system offers a hostile environment with antimicrobials and reactive oxygen species (ROS) that are detrimental to bacterial pathogens, forcing them to adapt and evolve for survival. However, the contribution of oxidative stress to pathogen evolution remains elusive. Using an experimental evolution strategy, we show that exposure of the opportunistic pathogen Pseudomonas aeruginosa to sub-lethal hydrogen peroxide (H2O2) levels over 120 generations led to the emergence of pro-biofilm rough small colony variants (RSCVs), which could be abrogated by l-glutathione antioxidants. Comparative genomic analysis of the RSCVs revealed that mutations in the wspF gene, which encodes for a repressor of WspR diguanylate cyclase (DGC), were responsible for increased intracellular cyclic-di-GMP content and production of Psl exopolysaccharide. Psl provides the first line of defence against ROS and macrophages, ensuring the survival fitness of RSCVs over wild-type P. aeruginosa. Our study demonstrated that ROS is an essential driving force for the selection of pro-biofilm forming pathogenic variants. Understanding the fundamental mechanism of these genotypic and phenotypic adaptations will improve treatment strategies for combating chronic infections. PMID:27881736

  14. Comparison of biotyping methods as alternative identification tools to molecular typing of pathogenic Cryptococcus species in sub-Saharan Africa.

    PubMed

    Nyazika, Tinashe K; Robertson, Valerie J; Nherera, Brenda; Mapondera, Prichard T; Meis, Jacques F; Hagen, Ferry

    2016-03-01

    Cryptococcal meningitis is the leading fungal infection and AIDS defining opportunistic illness in patients with late stage HIV infection, particularly in South-East Asia and sub-Saharan Africa. Given the high mortality, clinical differences and the extensive ecological niche of Cryptococcus neoformans and Cryptococcus gattii species complexes, there is need for laboratories in sub-Sahara African countries to adopt new and alternative reliable diagnostic algorithms that rapidly identify and distinguish these species. We biotyped 74 and then amplified fragment length polymorphism (AFLP) genotyped 66 Cryptococcus isolates from a cohort of patients with HIV-associated cryptococcal meningitis. C. gattii sensu lato was isolated at a prevalence of 16.7% (n = 11/66) and C. neoformans sensu stricto was responsible for 83.3% (n = 55/66) of the infections. l-Canavanine glycine bromothymol blue, yeast-carbon-base-d-proline-d-tryptophan and creatinine dextrose bromothymol blue thymine were able to distinguish pathogenic C. gattii sensu lato from C. neoformans sensu stricto species when compared with AFLP genotyping. This study demonstrates high C. gattii sensu lato prevalence in Zimbabwe. In addition, biotyping methods can be used as alternative diagnostic tools to molecular typing in resource-limited areas for differentiating pathogenic Cryptococcus species.

  15. Comparison of biotyping methods as alternative identification tools to molecular typing of pathogenic Cryptococcus species in sub-Saharan Africa

    PubMed Central

    Nyazika, Tinashe K.; Robertson, Valerie J.; Nherera, Brenda; Mapondera, Prichard T.; Meis, Jacques F.; Hagen, Ferry

    2015-01-01

    Summary Cryptococcal meningitis is the leading fungal infection and AIDS defining opportunistic illness in patients with late stage HIV infection, particularly in South-East Asia and sub-Saharan Africa. Given the high mortality, clinical differences and the extensive ecological niche of Cryptococcus neoformans and Cryptococcus gattii species complexes, there is need for laboratories in sub-Sahara African countries to adopt new and alternative reliable diagnostic algorithms that rapidly identify and distinguish these species. We biotyped 74 and then amplified fragment length polymorphism (AFLP) genotyped 66 Cryptococcus isolates from a cohort of patients with HIV-associated cryptococcal meningitis. Cryptococcus gattii sensu lato was isolated at a prevalence of 16.7% (n = 11/66) and C. neoformans sensu stricto was responsible for 83.3% (n = 55/66) of the infections. l-Canavanine glycine bromothymol blue, yeast-carbon-base-d-proline-d-tryptophan and creatinine dextrose bromothymol blue thymine were able to distinguish pathogenic C. gattii sensu lato from C. neoformans sensu stricto species when compared with amplified fragment length polymorphism genotyping. This study demonstrates high C. gattii sensu lato prevalence in Zimbabwe. In addition, biotyping methods can be used as alternative diagnostic tools to molecular typing in resource-limited areas for differentiating pathogenic Cryptococcus species. PMID:26661484

  16. Candida and Fusarium species known as opportunistic human pathogens from customer-accessible parts of residential washing machines.

    PubMed

    Babič, Monika Novak; Zalar, Polona; Ženko, Bernard; Schroers, Hans-Josef; Džeroski, Sašo; Gunde-Cimerman, Nina

    2015-03-01

    Energy constraints have altered consumer practice regarding the use of household washing machines. Washing machines were developed that use lower washing temperatures, smaller amounts of water and biodegradable detergents. These conditions may favour the enrichment of opportunistic human pathogenic fungi. We focused on the isolation of fungi from two user-accessible parts of washing machines that often contain microbial biofilms: drawers for detergents and rubber door seals. Out of 70 residential washing machines sampled in Slovenia, 79% were positive for fungi. In total, 72 strains belonging to 12 genera and 26 species were isolated. Among these, members of the Fusarium oxysporum and Fusarium solani species complexes, Candida parapsilosis and Exophiala phaeomuriformis represented 44% of fungi detected. These species are known as opportunistic human pathogens and can cause skin, nail or eye infections also in healthy humans. A machine learning analysis revealed that presence of detergents and softeners followed by washing temperature, represent most critical factors for fungal colonization. Three washing machines with persisting malodour that resulted in bad smelling laundry were analysed for the presence of fungi and bacteria. In these cases, fungi were isolated in low numbers (7.5 %), while bacteria Micrococcus luteus, Pseudomonas aeruginosa, and Sphingomonas species prevailed.

  17. Marine Sponge-Derived Streptomyces sp. SBT343 Extract Inhibits Staphylococcal Biofilm Formation

    PubMed Central

    Balasubramanian, Srikkanth; Othman, Eman M.; Kampik, Daniel; Stopper, Helga; Hentschel, Ute; Ziebuhr, Wilma; Oelschlaeger, Tobias A.; Abdelmohsen, Usama R.

    2017-01-01

    Staphylococcus epidermidis and Staphylococcus aureus are opportunistic pathogens that cause nosocomial and chronic biofilm-associated infections. Indwelling medical devices and contact lenses are ideal ecological niches for formation of staphylococcal biofilms. Bacteria within biofilms are known to display reduced susceptibilities to antimicrobials and are protected from the host immune system. High rates of acquired antibiotic resistances in staphylococci and other biofilm-forming bacteria further hamper treatment options and highlight the need for new anti-biofilm strategies. Here, we aimed to evaluate the potential of marine sponge-derived actinomycetes in inhibiting biofilm formation of several strains of S. epidermidis, S. aureus, and Pseudomonas aeruginosa. Results from in vitro biofilm-formation assays, as well as scanning electron and confocal microscopy, revealed that an organic extract derived from the marine sponge-associated bacterium Streptomyces sp. SBT343 significantly inhibited staphylococcal biofilm formation on polystyrene, glass and contact lens surfaces, without affecting bacterial growth. The extract also displayed similar antagonistic effects towards the biofilm formation of other S. epidermidis and S. aureus strains tested but had no inhibitory effects towards Pseudomonas biofilms. Interestingly the extract, at lower effective concentrations, did not exhibit cytotoxic effects on mouse fibroblast, macrophage and human corneal epithelial cell lines. Chemical analysis by High Resolution Fourier Transform Mass Spectrometry (HRMS) of the Streptomyces sp. SBT343 extract proportion revealed its chemical richness and complexity. Preliminary physico-chemical characterization of the extract highlighted the heat-stable and non-proteinaceous nature of the active component(s). The combined data suggest that the Streptomyces sp. SBT343 extract selectively inhibits staphylococcal biofilm formation without interfering with bacterial cell viability. Due to

  18. Marine Sponge-Derived Streptomyces sp. SBT343 Extract Inhibits Staphylococcal Biofilm Formation.

    PubMed

    Balasubramanian, Srikkanth; Othman, Eman M; Kampik, Daniel; Stopper, Helga; Hentschel, Ute; Ziebuhr, Wilma; Oelschlaeger, Tobias A; Abdelmohsen, Usama R

    2017-01-01

    Staphylococcus epidermidis and Staphylococcus aureus are opportunistic pathogens that cause nosocomial and chronic biofilm-associated infections. Indwelling medical devices and contact lenses are ideal ecological niches for formation of staphylococcal biofilms. Bacteria within biofilms are known to display reduced susceptibilities to antimicrobials and are protected from the host immune system. High rates of acquired antibiotic resistances in staphylococci and other biofilm-forming bacteria further hamper treatment options and highlight the need for new anti-biofilm strategies. Here, we aimed to evaluate the potential of marine sponge-derived actinomycetes in inhibiting biofilm formation of several strains of S. epidermidis, S. aureus, and Pseudomonas aeruginosa. Results from in vitro biofilm-formation assays, as well as scanning electron and confocal microscopy, revealed that an organic extract derived from the marine sponge-associated bacterium Streptomyces sp. SBT343 significantly inhibited staphylococcal biofilm formation on polystyrene, glass and contact lens surfaces, without affecting bacterial growth. The extract also displayed similar antagonistic effects towards the biofilm formation of other S. epidermidis and S. aureus strains tested but had no inhibitory effects towards Pseudomonas biofilms. Interestingly the extract, at lower effective concentrations, did not exhibit cytotoxic effects on mouse fibroblast, macrophage and human corneal epithelial cell lines. Chemical analysis by High Resolution Fourier Transform Mass Spectrometry (HRMS) of the Streptomyces sp. SBT343 extract proportion revealed its chemical richness and complexity. Preliminary physico-chemical characterization of the extract highlighted the heat-stable and non-proteinaceous nature of the active component(s). The combined data suggest that the Streptomyces sp. SBT343 extract selectively inhibits staphylococcal biofilm formation without interfering with bacterial cell viability. Due to

  19. Epidemiological survey of zoonotic pathogens in feral pigeons (Columba livia var. domestica) and sympatric zoo species in Southern Spain.

    PubMed

    Cano-Terriza, David; Guerra, Rafael; Lecollinet, Sylvie; Cerdà-Cuéllar, Marta; Cabezón, Oscar; Almería, Sonia; García-Bocanegra, Ignacio

    2015-12-01

    A cross-sectional study was carried out to determine the prevalence of pathogenic zoonotic agents (flaviviruses, avian influenza viruses (AIVs), Salmonella spp. and Toxoplasma gondii) in feral pigeons and sympatric zoo animals from Córdoba (Southern Spain) between 2013 and 2014. Antibodies against flaviviruses were detected in 7.8% out of 142 (CI95%: 3.7-11.8) pigeons, and 8.2% of 49 (CI95%: 0.9-15.4) of zoo animals tested. Antibodies with specificity against West Nile virus (WNV) and Usutu virus (USUV) were confirmed both in pigeons and in zoo birds. Even though seropositivity to AIVs was not detected in any of the analyzed pigeons, 17.9% of 28 (CI95%: 3.7-32.0) zoo birds tested showed positive results. Salmonella spp. was not isolated in any of 152 fecal samples collected from pigeons, while 6.8% of 44 zoo animals were positive. Antibodies against T. gondii were found in 9.2% of 142 (CI95%: 4.8-13.6) feral pigeons and 26.9% of 108 (CI95%: 19.6-34.1) zoo animals. This is the first study on flaviviruses and T. gondii in feral pigeons and captive zoo species in Spain. Antibodies against WNV and USUV detected in non-migratory pigeons and captive zoo animals indicate local circulation of these emerging pathogens in the study area. T. gondii was widespread in species analyzed. This finding could be of importance for Public Health and Conservation of endangered species present in zoo parks. Pigeons and zoo animals may be included as sentinel species for monitoring zoonotic pathogens in urban areas.

  20. Tomato response traits to pathogenic Pseudomonas species: Does nitrogen limitation matter?

    PubMed

    Royer, Mathilde; Larbat, Romain; Le Bot, Jacques; Adamowicz, Stéphane; Nicot, Philippe C; Robin, Christophe

    2016-03-01

    Induced chemical defence is a cost-efficient protective strategy, whereby plants induce the biosynthesis of defence-related compounds only in the case of pest attack. Plant responses that are pathogen specific lower the cost of defence, compared to constitutive defence. As nitrogen availability (N) in the root zone is one of the levers mediating the concentration of defence-related compounds in plants, we investigated its influence on response traits of tomato to two pathogenic bacteria, growing plants hydroponically at low or high N supply. Using two sets of plants for each level of N supply, we inoculated one leaf of one set of plants with Pseudomonas syringae, and inoculated the stem of other set of plants with Pseudomonas corrugata. Tomato response traits (growth, metabolites) were investigated one and twelve days after inoculation. In infected areas, P. syringae decreased carbohydrate concentrations whereas they were increased by P. corrugata. P. syringae mediated a redistribution of carbon within the phenylpropanoid pathway, regardless of N supply: phenolamides, especially caffeoylputrescine, were stimulated, impairing defence-related compounds such as chlorogenic acid. Inoculation of P. syringae produced strong and sustainable systemic responses. By contrast, inoculation of P. corrugata induced local and transient responses. The effects of pathogens on plant growth and leaf gas exchanges appeared to be independant of N supply. This work shows that the same genus of plant pathogens with different infection strategies can mediate contrasted plant responses.

  1. Antimicrobial Activity of neo-Clerodane Diterpenoids isolated from Lamiaceae Species against Pathogenic and Food Spoilage Microorganisms.

    PubMed

    Bozov, Petko; Girova, Tania; Prisadova, Natalia; Hristova, Yana; Gochev, Velizar

    2015-11-01

    Antimicrobial activity of nineteen neo-clerodane diterpenoids, isolated from the acetone extracts of the aerial parts of Scutellaria and Salvia species (Lamiaceae) were tested against thirteen strains belonging to nine different species of pathogenic and food spoilage bacteria Aeromonas hydrophila, Bacillus cereus, Escherichia coli, Listeria monocytogenes, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella abony and Staphylococcus aureus as well as against two yeast strains belonging to species Candida albicans. Seven of the evaluated compounds scutalpin A, scutalpin E, scutalpin F, salviarin, splenolide A, splenolide B and splendidin demonstrated antimicrobial activity against used test microbial strains, the rest of the compounds were inactive within the studied concentration range. Among all of the tested compounds the highest antimicrobial activity was detected for scutalpin A against Staphylococcus aureus (MIC 25 µg/mL).

  2. Regulation of Staphylococcal Enterotoxin Biosynthesis

    DTIC Science & Technology

    1981-05-01

    incubation mixture (1001 Ai was precipitated with sary to) prepare t.5N2. Potritv(if all itlasouit preparak- I ml of 20’, t richloroacet ic acid and hoiled...deoxyribonucleic acid (DNA) species. Additional studies demonstrated that the toxin phenotype and by implication, the toxin gene, could be transmitted to...to the amino acid sequence of SEB do not reside on the majority (approx. 2/3) of pSN2. However, if the structural SEB gene is present in pSN2, it

  3. Utilization of size polymorphism in ITS1 and ITS2 regions for identification of pathogenic yeast species.

    PubMed

    Khodadadi, Hossein; Karimi, Ladan; Jalali-Zand, Niloufar; Adin, Hassan; Mirhendi, Hossein

    2017-01-09

    Despite the existence of a variety of available yeast identification strategies, easier and more cost-effective methods are required for routine use in clinical laboratories. The internal transcribed spacer (ITS) regions of fungal rRNA genes exhibit variable sizes depending on the yeast species. In the present study, fragment size polymorphism (FSP) analysis of the ITS1 and ITS2 regions for identification of the clinically most important yeast species was assessed. The ITS1 and ITS2 regions of 190 strains, including isolates of 31 standard strains and 159 clinical isolates, were separately PCR-amplified with two primer sets: ITS1-ITS2 and ITS3-ITS4. PCR products were mixed and the two-band electrophoretic pattern of each sample was analysed according to the size of the ITS regions as predicted from the GenBank database. Using this method and avoiding expensive tools such as sequencing or capillary electrophoresis, we were able to differentiate nearly all pathogenic yeast species, including Candida albicans, Candida tropicalis, Candida glabrata, Candida parapsilosis, Candida krusei, Candida guilliermondii, Candida kefyr, Candida lusitaniae, Candida rugosa, Cryptococcus neoformans, and Saccharomyces cerevisiae. The method showed limited discriminatory power to differentiate species of the Candida parapsilosis complex. Differentiation of C. albicans and C. tropicalis needs already identified controls. Nevertheless, the method benefits from advantages such as lower cost, higher speed and wider range of species than some commercial yeast-identification methods. We consider this method one of the easiest molecular approaches for identifying a wide range of human pathogenic yeast species, applicable to both diagnostic and epidemiological purposes.

  4. Prevalence of Bovine Mastitis Pathogens in Bulk Tank Milk in China

    PubMed Central

    Wang, Ya Jing; Qin, Yun; Guix Vallverdú, Roger; Maldonado García, Jaime; Sun, Wei; Li, Shengli; Cao, Zhijun

    2016-01-01

    The objectives of this study were to estimate the herd prevalence of major mastitis pathogens in bulk tank milk (BTM) in China dairy herds, to determine the relationship between the presence of mastitis pathogens and bulk tank milk somatic cell counts (BTSCC), and to investigate the impact of different dairy cattle farming modes and region on bacterial species. BTM samples collected from 894 dairy herds in China were examined for the presence of mastitis pathogens. The Flinders Technology Associates (FTA) cards were used for BTM sample collection, storage, and transportation and bacterial DNA amplification by real-time PCR. Among contagious pathogens, Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae were detected in 50.1, 92.2, and 72.3% of the 894 BTM samples, respectively. Among environmental pathogens, E. coli, Streptococcus uberis, Enterococcus spp., Klebsiella spp., Serratia marcescens, Corynebacterium bovis, and Arcanobacterium pyogenes were detected in 28.6, 8.9, 35.7, 20.0, 1.3, 17.0, and 67.2% of the BTM samples, respectively. Staphylococcal β-lactamase gene was detected in 61.7% of the BTM samples. The presence of Staphylococcus aureus and Arcanobacterium pyogenes were significantly associated with high BTSCC, respectively. Significant differences were found in presence of Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae in BTM sampled from the small household farms, dairy-farming communities, and large-scaled dairy farms. There were significant differences in the presence of Streptococcus agalactiae, Streptococcus dysgalactiae, Arcanobacterium pyogenes, staphylococcal β-lactamase gene, Staphylococcus spp., Klebsiella spp., Enterococcus spp., and Streptococcus uberis in BTM among Inner Mongolia, Heilongjiang, and Hebei province. In conclusion, contagious mammary pathogens are predominated among pathogens in BTM samples in China. PMID:27187065

  5. Gene Network Polymorphism Illuminates Loss and Retention of Novel RNAi Silencing Components in the Cryptococcus Pathogenic Species Complex

    PubMed Central

    Clancey, Shelly Applen; Wang, Xuying; Heitman, Joseph

    2016-01-01

    RNAi is a ubiquitous pathway that serves central functions throughout eukaryotes, including maintenance of genome stability and repression of transposon expression and movement. However, a number of organisms have lost their RNAi pathways, including the model yeast Saccharomyces cerevisiae, the maize pathogen Ustilago maydis, the human pathogen Cryptococcus deuterogattii, and some human parasite pathogens, suggesting there may be adaptive benefits associated with both retention and loss of RNAi. By comparing the RNAi-deficient genome of the Pacific Northwest Outbreak C. deuterogattii strain R265 with the RNAi-proficient genomes of the Cryptococcus pathogenic species complex, we identified a set of conserved genes that were lost in R265 and all other C. deuterogattii isolates examined. Genetic and molecular analyses reveal several of these lost genes play roles in RNAi pathways. Four novel components were examined further. Znf3 (a zinc finger protein) and Qip1 (a homolog of N. crassa Qip) were found to be essential for RNAi, while Cpr2 (a constitutive pheromone receptor) and Fzc28 (a transcription factor) are involved in sex-induced but not mitosis-induced silencing. Our results demonstrate that the mitotic and sex-induced RNAi pathways rely on the same core components, but sex-induced silencing may be a more specific, highly induced variant that involves additional specialized or regulatory components. Our studies further illustrate how gene network polymorphisms involving known components of key cellular pathways can inform identification of novel elements and suggest that RNAi loss may have been a core event in the speciation of C. deuterogattii and possibly contributed to its pathogenic trajectory. PMID:26943821

  6. Clinical Significance and Pathogenesis of Staphylococcal Small Colony Variants in Persistent Infections

    PubMed Central

    Becker, Karsten; Löffler, Bettina

    2016-01-01

    SUMMARY Small colony variants (SCVs) were first described more than 100 years ago for Staphylococcus aureus and various coagulase-negative staphylococci. Two decades ago, an association between chronic staphylococcal infections and the presence of SCVs was observed. Since then, many clinical studies and observations have been published which tie recurrent, persistent staphylococcal infections, including device-associated infections, bone and tissue infections, and airway infections of cystic fibrosis patients, to this special phenotype. By their intracellular lifestyle, SCVs exhibit so-called phenotypic (or functional) resistance beyond the classical resistance mechanisms, and they can often be retrieved from therapy-refractory courses of infection. In this review, the various clinical infections where SCVs can be expected and isolated, diagnostic procedures for optimized species confirmation, and the pathogenesis of SCVs, including defined underlying molecular mechanisms and the phenotype switch phenomenon, are presented. Moreover, relevant animal models and suggested treatment regimens, as well as the requirements for future research areas, are highlighted. PMID:26960941

  7. Phytophthora species recovered from irrigation reservoirs in Mississippi and Alabama nurseries and pathogenicity of three new species.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    From a survey of containment ponds for Phytophthora spp. at one nursery each in Alabama and Mississippi, eight species and one taxon were recovered with P. gonapodyides dominant in cooler months and P. hydropathica in warmer months, accounting for 39.6% and 46.6% overall recovery, respectively. Amo...

  8. Phytophthora species recovered from irrigation reservoirs in Mississippi and Alabama nurseries and pathogenicity of three new species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    From a survey of containment ponds for Phytophthora spp. at one nursery each in Alabama and Mississippi, eight species and one taxon were recovered with P. gonapodyides dominant in cooler months and P. hydropathica in warmer months, accounting for 39.6% and 46.6% overall recovery, respectively. Amo...

  9. Strategies for the identification and tracking of cronobacter species: an opportunistic pathogen of concern to neonatal health.

    PubMed

    Yan, Qiongqiong; Fanning, Séamus

    2015-01-01

    Cronobacter species are emerging opportunistic food-borne pathogens, which consists of seven species, including C. sakazakii, C. malonaticus, C. muytjensii, C. turicensis, C. dublinensis, C. universalis, and C. condimenti. The organism can cause severe clinical infections, including necrotizing enterocolitis, septicemia, and meningitis, predominately among neonates <4 weeks of age. Cronobacter species can be isolated from various foods and their surrounding environments; however, powdered infant formula (PIF) is the most frequently implicated food source linked with Cronobacter infection. This review aims to provide a summary of laboratory-based strategies that can be used to identify and trace Cronobacter species. The identification of Cronobacter species using conventional culture method and immuno-based detection protocols were first presented. The molecular detection and identification at genus-, and species-level along with molecular-based serogroup approaches are also described, followed by the molecular sub-typing methods, in particular pulsed-field gel electrophoresis and multi-locus sequence typing. Next generation sequence approaches, including whole genome sequencing, DNA microarray, and high-throughput whole-transcriptome sequencing, are also highlighted. Appropriate application of these strategies would contribute to reduce the risk of Cronobacter contamination in PIF and production environments, thereby improving food safety and protecting public health.

  10. An outbreak of low pathogenic avian influenza in a mixed-species aviculture unit in Dubai in 2005.

    PubMed

    Kent, Jo; Bailey, Tom; Silvanose, Christu-Das; McKeown, Sean; Wernery, Ulrich; Kinne, Joerg; Manvell, Ruth

    2006-09-01

    This case describes an outbreak of low pathogenic hemagglutinin 9 neuraminidase 2 avian influenza virus (AIV) in two white-bellied bustards (Eupodotis senegalensis), one stone curlew (Burhinus oedicnemius), and a blacksmith plover (Antibyx armatus) in a private zoologic collection in Dubai, United Arab Emirates. The four birds showed signs of respiratory disease, and all died as a result of disease or euthanasia. Attention has been paid to the diagnostic process and common differential diagnosis for upper respiratory tract disease in bustards, curlews, and plovers. To the knowledge of the authors, AIV has not been previously described in these species.

  11. Pythium species causing damping-off of alfalfa in Minnesota: Identification, pathogenicity and fungicide sensitivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Damping-off and seed rot is an important disease of alfalfa, severely affecting stand establishment when conditions favor the disease. Globally, 15 Pythium species are reported to cause damping-off and seed rot of alfalfa, although surveys of species causing disease on alfalfa in Minnesota are lacki...

  12. Brachypodium distachyon: a model species to study cereal-pathogen interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brachypodium distachyon is rapidly emerging as a model grass species for temperate cereal crops. Due to its undemanding growth requirements, small stature, inbreeding reproductive strategy, and particularly its small genome (~ 320 Mbp; 2x = 2n = 10), this species is being adopted by a large number o...

  13. Pathogenicity and virulence of Pythium species obtained from forest nursery soils on Douglas-fir seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pythium species are common soilborne oomycetes that occur in forest nursery soils in the Pacific Northwest (PNW) region of the United States. Numerous species have been described. However, with the exception of P. aphanidermatum, P. irregulare, P.mamillatum, and P. ultimum, little is known about the...

  14. Species tree estimation for the late blight pathogen, Phytophthora infestans, and close relatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary process...

  15. Species, developmental stage and infection with microbial pathogens of engorged ticks removed from dogs and questing ticks.

    PubMed

    Leschnik, M W; Khanakah, G; Duscher, G; Wille-Piazzai, W; Hörweg, C; Joachim, A; Stanek, G

    2012-12-01

    Research into tick-borne diseases implies vector sampling and the detection and identification of microbial pathogens. Ticks were collected simultaneously from dogs that had been exposed to tick bites and by flagging the ground in the area in which the dogs had been exposed. In total, 200 ticks were sampled, of which 104 came from dogs and 96 were collected by flagging. These ticks were subsequently examined for DNA of Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia spp. and Babesia canis. A mixed sample of adult ticks and nymphs of Ixodes ricinus (Ixodida: Ixodidae) and Haemaphysalis concinna (Ixodida: Ixodidae) was obtained by flagging. Female I. ricinus and adult Dermacentor reticulatus (Ixodida: Ixodidae) ticks dominated the engorged ticks removed from dogs. Rickettsia spp. were detected in 17.0% of the examined ticks, A. phagocytophilum in 3.5%, B. canis in 1.5%, and B. burgdorferi s.l. in 16.0%. Ticks with multiple infections were found only among the flagging sample. The ticks removed from the dogs included 22 infected ticks, whereas the flagging sample included 44 infected ticks. The results showed that the method for collecting ticks influences the species composition of the sample and enables the detection of a different pattern of pathogens. Sampling strategies should be taken into consideration when interpreting studies on tick-borne pathogens.

  16. Comparative Genomics of the Staphylococcus intermedius Group of Animal Pathogens

    PubMed Central

    Ben Zakour, Nouri L.; Beatson, Scott A.; van den Broek, Adri H. M.; Thoday, Keith L.; Fitzgerald, J. Ross

    2012-01-01

    The Staphylococcus intermedius group consists of three closely related coagulase-positive bacterial species including S. intermedius, Staphylococcus pseudintermedius, and Staphylococcus delphini. S. pseudintermedius is a major skin pathogen of dogs, which occasionally causes severe zoonotic infections of humans. S. delphini has been isolated from an array of different animals including horses, mink, and pigeons, whereas S. intermedius has been isolated only from pigeons to date. Here we provide a detailed analysis of the S. pseudintermedius whole genome sequence in comparison to high quality draft S. intermedius and S. delphini genomes, and to other sequenced staphylococcal species. The core genome of the SIG was highly conserved with average nucleotide identity (ANI) between the three species of 93.61%, which is very close to the threshold of species delineation (95% ANI), highlighting the close-relatedness of the SIG species. However, considerable variation was identified in the content of mobile genetic elements, cell wall-associated proteins, and iron and sugar transporters, reflecting the distinct ecological niches inhabited. Of note, S. pseudintermedius ED99 contained a clustered regularly interspaced short palindromic repeat locus of the Nmeni subtype and S. intermedius contained both Nmeni and Mtube subtypes. In contrast to S. intermedius and S. delphini and most other staphylococci examined to date, S. pseudintermedius contained at least nine predicted reverse transcriptase Group II introns. Furthermore, S. pseudintermedius ED99 encoded several transposons which were largely responsible for its multi-resistant phenotype. Overall, the study highlights extensive differences in accessory genome content between closely related staphylococcal species inhabiting distinct host niches, providing new avenues for research into pathogenesis and bacterial host-adaptation. PMID:22919635

  17. Molecular and pathogenic variation within Melampsora on Salix in western North America reveals numerous cryptic species.

    PubMed

    Bennett, Chandalin; Aime, M Catherine; Newcombe, George

    2011-01-01

    In North America Melampsora rusts that parasitize willows (Salix species) have never been adequately studied and mostly have been referred to a collective species, Melampsora epitea (Kunze & Schm.) Thüm, of European origin. Even taxa that are nominally distinct from M. epitea, such as M. abieti-caprearum and M. paradoxa, currently are considered to be "races" of M. epitea. Within the range of our field surveys and collections in the Pacific Northwest and the Southwest only two species of Melampsora thus were expected: M. epitea (including its races) and M. ribesii-purpureae. In this study of Melampsora on 19 species of Salix in the western United States 14 phylogenetic species, or phylotypes, were apparent from nuclear rDNA sequencing of 140 collections or isolates. Our collections of the races of M. epitea, M. abieti-caprearum and M. epitea f. sp. tsugae belonged to one phylotype, termed lineage 'N'. Assuming that M. ribesii-purpureae represents one other phylotype, 12 phylotypes still are unaccounted for by current taxonomy. Moreover Eurasian M. ribesii-purpureae was not closely related to any of the phylotypes reported here. Even more problematic was the resistance of Eurasian species of Salix, including the type host of M. epitea, S. alba, to North American Melampsora, including phylotype 'N', in both the field and in inoculation experiments. These results suggest the need for the description of many new species of Melampsora on Salix in western North America. Additional analyses presented here might guide further research in this direction.

  18. Binding of flavonoids to staphylococcal enterotoxin B.

    PubMed

    Benedik, Evgen; Skrt, Mihaela; Podlipnik, Crtomir; Ulrih, Nataša Poklar

    2014-12-01

    Staphylococcal enterotoxins are metabolic products of Staphylococcus aureus that are responsible for the second-most-commonly reported type of food poisoning. Polyphenols are known to interact with proteins to form complexes, the properties of which depend on the structures of both the polyphenols and the protein. In the present study, we investigated the binding of four flavonoid polyphenols to Staphylococcal enterotoxin B (SEB) at pH 7.5 and 25 °C: (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), kaempferol-3-glucoside (KAM-G) and kaempferol (KAM). Fluorescence emission spectrometry and molecular docking were applied to compare experimentally determined binding parameters with molecular modeling. EGCG showed an order of magnitude higher binding constant (1.4 × 10(5) M(-1)) than the other studied polyphenols. Our blind-docking results showed that EGCG and similar polyphenolic ligands is likely to bind to the channel at the surface of SEB that is responsible for the recognition of the T-cell beta chain fragment and influence the adhesion of SEB to T cells.

  19. Staphylococcal bacteraemia, fusidic acid, and jaundice.

    PubMed

    Humble, M W; Eykyn, S; Phillips, I

    1980-06-21

    Fusidic acid was used to treat 131 out of 250 patients with staphylococcal bacteraemia over 10 years. Other antimicrobial agents were given to the 119 remaining patients. Thirty-seven patients were already jaundiced before antibiotic treatment was started. Jaundice developed during treatment in 38 out of 112 patients given fusidic acid (34%) and in two out of 101 patients given other antimicrobials. The incidence of jaundice was higher in patients given fusidic acid intravenously (48%) rather than by mouth (13%). Jaundice appeared within 48 hours after the administration of fusidic acid in 93% of these cases. When the drug was stopped serum bilirubin concentrations fell to normal values within four days in those patients in whom they had been previously normal and who survived the bacteraemic episode. Fusidic acid was associated with increasing jaundice in 13 of 19 patients (68%) already jaundiced before it was given. In six out of 32 patients who developed jaundice while receiving intravenous fusidic acid serum alkaline phosphatase activity was raised suggestive of cholestatic jaundice. The mechanism in the remaining patients was unknown. Fusidic acid, particularly the intravenous preparation, in invaluable in treating severe staphylococcal infection but should be used with caution in patients with abnormal liver function. Patients receiving intravenous fusidic acid should be given the oral form of the drug as soon as their clinical condition permits.

  20. Staphylococcal enterotoxin A gene-carrying Staphylococcus aureus isolated from foods and its control by crude alkaloid from papaya leaves.

    PubMed

    Handayani, Lita; Faridah, Didah Nur; Kusumaningrum, Harsi D

    2014-11-01

    Staphylococcus aureus is a known pathogen causing intoxication by producing enterotoxins in food. Staphylococcal enterotoxin A is one of the enterotoxins commonly implicated in staphylococcal food poisoning. The ability of crude alkaloid extract from papaya leaves to inhibit the growth of S. aureus and staphylococcal enterotoxin A synthesis was investigated. Staphylococcal enterotoxin A gene-carrying S. aureus was isolated from raw milk and ready-to-eat foods. Crude alkaloid was extracted from ground, dried papaya leaves using ultrasonic-assisted extraction, and a MIC of the alkaloid was determined by the broth macrodilution method. Furthermore, S. aureus isolate was exposed to the crude alkaloid extract at one- and twofold MIC, and the expression of sea was subsequently analyzed using a quantitative reverse transcription real-time PCR. Ten isolates of S. aureus were obtained, and nine of those isolates were sea carriers. The yield of crude alkaloid extract was 0.48 to 1.82% per dry weight of papaya leaves. A MIC of crude alkaloid to S. aureus was 0.25 mg/ml. After exposure to the alkaloid at 0.25 and 0.5 mg/ml for 2 h, a significant increase in cycle threshold values of sea was observed. The sea was expressed 29 and 41 times less when S. aureus was exposed to crude alkaloid at one- and twofold MIC, respectively. This study revealed that crude alkaloid of papaya leaves could control staphylococcal enterotoxin A gene-carrying S. aureus by suppressing the expression of sea, in addition to the ability to inhibit the growth of S. aureus. The expression of sea was successfully quantified.

  1. Full Genome Sequence Analysis of Two Isolates Reveals a Novel Xanthomonas Species Close to the Sugarcane Pathogen Xanthomonas albilineans

    PubMed Central

    Pieretti, Isabelle; Cociancich, Stéphane; Bolot, Stéphanie; Carrère, Sébastien; Morisset, Alexandre; Rott, Philippe; Royer, Monique

    2015-01-01

    Xanthomonas albilineans is the bacterium responsible for leaf scald, a lethal disease of sugarcane. Within the Xanthomonas genus, X. albilineans exhibits distinctive genomic characteristics including the presence of significant genome erosion, a non-ribosomal peptide synthesis (NRPS) locus involved in albicidin biosynthesis, and a type 3 secretion system (T3SS) of the Salmonella pathogenicity island-1 (SPI-1) family. We sequenced two X. albilineans-like strains isolated from unusual environments, i.e., from dew droplets on sugarcane leaves and from the wild grass Paspalum dilatatum, and compared these genomes sequences with those of two strains of X. albilineans and three of Xanthomonas sacchari. Average nucleotide identity (ANI) and multi-locus sequence analysis (MLSA) showed that both X. albilineans-like strains belong to a new species close to X. albilineans that we have named “Xanthomonas pseudalbilineans”. X. albilineans and “X. pseudalbilineans” share many genomic features including (i) the lack of genes encoding a hypersensitive response and pathogenicity type 3 secretion system (Hrp-T3SS), and (ii) genome erosion that probably occurred in a common progenitor of both species. Our comparative analyses also revealed specific genomic features that may help X. albilineans interact with sugarcane, e.g., a PglA endoglucanase, three TonB-dependent transporters and a glycogen metabolism gene cluster. Other specific genomic features found in the “X. pseudalbilineans” genome may contribute to its fitness and specific ecological niche. PMID:26213974

  2. Dangerous Liaisons: Caspase-11 and Reactive Oxygen Species Crosstalk in Pathogen Elimination

    PubMed Central

    Roberts, JoAnn Simone; Yilmaz, Ӧzlem

    2015-01-01

    Recently, the focus of murine caspase-11 and human orthologs caspase-4, -5 research has been on their novel function to induce noncanonical inflammasome activation in direct response to Gram-negative bacterial infection. On the other hand, a new role in anti-bacterial autophagy has been attributed to caspase-11, -4 and -5, which currently stands largely unexplored. In this review, we connect lately emerged evidence that suggests these caspases have a key role in anti-bacterial autophagy and discuss the growing implications of a danger molecule—extracellular ATP—and NADPH oxidase-mediated ROS generation as novel inducers of human caspase-4, -5 signaling during infection. We also highlight the adeptness of persistent pathogens like Porphyromonas gingivalis, a Gram-negative anaerobe and successful colonizer of oral mucosa, to potentially interfere with the activated caspase-4 pathway and autophagy. While, the ability of caspase-4, -5 to promote autophagolysosomal fusion is not well understood, the abundance of caspase-4 in skin and other mucosal epithelial cells implies an important role for caspase-4 in mucosal defense, supporting the view that caspase-4, -5 may play a non-redundant part in innate immunity. Thus, this review will join the currently disconnected cutting-edge research thereby proposing a working model for regulation of caspase-4, -5 in pathogen elimination via cellular-trafficking. PMID:26426007

  3. Staphylococcus pseudintermedius sp. nov., a coagulase-positive species from animals.

    PubMed

    Devriese, Luc A; Vancanneyt, Marc; Baele, Margo; Vaneechoutte, Mario; De Graef, Evelyne; Snauwaert, Cindy; Cleenwerck, Ilse; Dawyndt, Peter; Swings, Jean; Decostere, Annemie; Haesebrouck, Freddy

    2005-07-01

    Four staphylococcal isolates from clinical and necropsy specimens from a cat, a dog, a horse and a parrot (Psittacus erithacus timneh) were found to constitute a distinct taxon. 16S rRNA gene sequence analysis revealed that its closest phylogenetic relatives are Staphylococcus intermedius and Staphylococcus delphini. Growth characteristics, biochemical features and DNA-DNA hybridizations demonstrated that the strains differ from these and other known species and that they represent a single, novel Staphylococcus species for which the name Staphylococcus pseudintermedius sp. nov. is proposed. The novel species is commonly confused with S. intermedius in routine diagnostic veterinary bacteriology. Although the strains described were isolated from lesions and show several characteristics typical of pathogenic staphylococci, such as coagulase, DNase and beta-haemolysin production, the pathogenic significance of the novel species remains unclear. The type strain, LMG 22219(T) (=ON 86(T)=CCUG 49543(T)), was isolated from lung tissue of a cat.

  4. Highly pathogenic avian influenza (H7N7): vaccination of zoo birds and transmission to non-poultry species.

    PubMed

    Philippa, Joost D W; Munster, Vincent J; Bolhuis, Hester van; Bestebroer, Theo M; Schaftenaar, Willem; Beyer, Walter E P; Fouchier, Ron A M; Kuiken, Thijs; Osterhaus, Albert D M E

    2005-12-30

    In 2003 an outbreak of highly pathogenic avian influenza virus (H7N7) struck poultry in The Netherlands. A European Commission directive made vaccination of valuable species in zoo collections possible under strict conditions. We determined pre- and post-vaccination antibody titres in 211 birds by haemagglutination inhibition test as a measure of vaccine efficacy. After booster vaccination, 81.5% of vaccinated birds developed a titre of > or =40, while overall geometric mean titre (GMT) was 190 (95% CI: 144-251). Birds of the orders Anseriformes, Galliformes and Phoenicopteriformes showed higher GMT, and larger percentages developed titres > or =40 than those of the other orders. Antibody response decreased with increasing mean body weight in birds > or =1.5 kg body weight. In the vicinity of the outbreak, H7N7 was detected by RT-PCR in wild species (mallards and mute swans) kept in captivity together with infected poultry, illustrating the potential threat of transmission from poultry into other avian species, and the importance of protecting valuable avian species by means of vaccination.

  5. Transmission dynamics of a zoonotic pathogen within and between wildlife host species.

    PubMed Central

    Begon, M; Hazel, S M; Baxby, D; Bown, K; Cavanagh, R; Chantrey, J; Jones, T; Bennett, M

    1999-01-01

    The transmission dynamics of the cowpox virus infection have been quantified in two mixed populations of bank voles (Clethrionomys glareolus) and wood mice (Apodemus sylvaticus), through analyses of detailed time-series of the numbers of susceptible, infectious and newly infected individuals. The cowpox virus is a zoonosis which circulates in these rodent hosts and has been shown to have an adverse effect on reproductive output. The transmission dynamics within species is best described as frequency dependent rather than density dependent, contrary to the 'mass action' assumption of most previous studies, both theoretical and empirical. Estimation of a transmission coefficient for each species in each population also allows annual and seasonal variations in transmission dynamics to be investigated through an analysis of regression residuals. Transmission between host species is found to be negligible despite their close cohabitation. The consequences of this for the combining ability of hosts as zoonotic reservoirs, and for apparent competition between hosts, are discussed. PMID:10584336

  6. Superoxol and aminopeptidase tests for identification of pathogenic Neisseria species and Moraxella (Branhamella) catarrhalis.

    PubMed

    Pérez, J L; Pulido, A; Gómez, E; Sauca, G; Martín, R

    1990-06-01

    The superoxol test, and prolyl aminopeptidase and gammaglutamyl aminopeptidase tests were evaluated for the detection of pathogenic Neisseria spp. using 317 strains of Neisseria-ceae. The superoxol test was positive for all 116 gonococci and 62 Moraxella (Branhamella) catarrhalis strains, but also for three strains of Neisseria meningitidis, one strain of Neisseria lactamica and eight saprophytic neisseriae. When using strains grown on Thayer-Martin medium, the positive and negative predictive values of the superoxol test for the identification of Neisseria gonorrhoeae were 96.7% and 100% respectively. Meningococci were the only neisseriae growing on Thayer-Martin medium that showed gamma-glutamyl aminopeptidase activity. The prolyl aminopeptidase test showed low specificity.

  7. Structural insights into species-specific features of the ribosome from the pathogen Staphylococcus aureus

    PubMed Central

    Eyal, Zohar; Matzov, Donna; Krupkin, Miri; Wekselman, Itai; Paukner, Susanne; Zimmerman, Ella; Rozenberg, Haim; Bashan, Anat; Yonath, Ada

    2015-01-01

    The emergence of bacterial multidrug resistance to antibiotics threatens to cause regression to the preantibiotic era. Here we present the crystal structure of the large ribosomal subunit from Staphylococcus aureus, a versatile Gram-positive aggressive pathogen, and its complexes with the known antibiotics linezolid and telithromycin, as well as with a new, highly potent pleuromutilin derivative, BC-3205. These crystal structures shed light on specific structural motifs of the S. aureus ribosome and the binding modes of the aforementioned antibiotics. Moreover, by analyzing the ribosome structure and comparing it with those of nonpathogenic bacterial models, we identified some unique internal and peripheral structural motifs that may be potential candidates for improving known antibiotics and for use in the design of selective antibiotic drugs against S. aureus. PMID:26464510

  8. Structural insights into species-specific features of the ribosome from the pathogen Staphylococcus aureus.

    PubMed

    Eyal, Zohar; Matzov, Donna; Krupkin, Miri; Wekselman, Itai; Paukner, Susanne; Zimmerman, Ella; Rozenberg, Haim; Bashan, Anat; Yonath, Ada

    2015-10-27

    The emergence of bacterial multidrug resistance to antibiotics threatens to cause regression to the preantibiotic era. Here we present the crystal structure of the large ribosomal subunit from Staphylococcus aureus, a versatile Gram-positive aggressive pathogen, and its complexes with the known antibiotics linezolid and telithromycin, as well as with a new, highly potent pleuromutilin derivative, BC-3205. These crystal structures shed light on specific structural motifs of the S. aureus ribosome and the binding modes of the aforementioned antibiotics. Moreover, by analyzing the ribosome structure and comparing it with those of nonpathogenic bacterial models, we identified some unique internal and peripheral structural motifs that may be potential candidates for improving known antibiotics and for use in the design of selective antibiotic drugs against S. aureus.

  9. Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

    NASA Technical Reports Server (NTRS)

    Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

    2003-01-01

    The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

  10. Purification of Staphylococcal β-Hemolysin and Its Action on Staphylococcal and Streptococcal Cell Walls

    PubMed Central

    Chesbro, William R.; Heydrick, Fred P.; Martineau, Roland; Perkins, Gail N.

    1965-01-01

    Chesbro, William R. (University of New Hampshire, Durham), Fred P. Heydrick, Roland Martineau, and Gail N. Perkins. Purification of staphylococcal β-hemolysin and its action on staphylococcal and streptococcal cell walls. J. Bacteriol. 89:378–389. 1965.—After growth of bovine-derived strains of Staphylococcus aureus in a completely dialyzable medium, the β-hemolysin in the culture supernatant fluids was purified by gradient-elution chromatography on cellulose phosphate. The purified hemolysin contained two components, demonstrable by immunodiffusion or electrophoresis, but was free from α-hemolysin, coagulase, Δ-hemolysin, enterotoxins A and B, glucuronidase, hyaluronidase, lipase, muramidase, Panton-Valentine leukocidin, phosphatase, and protease. The hemolysin was heat-labile and sulfhydryl-dependent, and the preparation was leukocidal for guinea pig macrophages. When rabbit red blood cell (RBC) stroma and staphylococcal or enterococcal cell walls were treated with the purified hemolysin, it liberated mucopolysaccharides from the rabbit RBC stroma, polysaccharides and mucopolysaccharides (or mucopeptides) from the staphyloccoal cell walls, and rhamnose, glucose, an unidentified monosaccharide, N-acetylglucosamine, and at least two polysaccharides from the enterococcal cell walls. The hemolytic and cell-wall degradative activities had similar thermal inactivation kinetics, pH optima, sedimentation coefficients, and chromatographic and electrophoretic mobilities; both required Mg and were inhibited by thiol-inactivating agents. Consequently, it seems likely that both activities are expressions of the same enzyme. PMID:14255704

  11. Comparative genomics of the Fusarium fujikuroi species complex: biosynthetic pathways metabolite production and plant pathogenicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium is a huge genus of filamentous fungi causing plant diseases in a wide range of host plants that result in high economic losses to world agriculture every year. Phylogenetic studies have shown that the genus Fusarium consists of different species complexes. One of them is the “Fusarium fujik...

  12. Resistance of closely-mown fine fescue and bentgrass species to snow mold pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Creeping bentgrass (Agrostis stolonifera) is the primary species used on golf courses in temperate regions but requires prophylactic fungicide treatment to prevent snow mold diseases. We hypothesized that fine fescues (Festuca spp.) and colonial bentgrass (A. capillaris) have superior resistance to...

  13. Emergence of Rare Species of Nontuberculous Mycobacteria as Potential Pathogens in Saudi Arabian Clinical Setting

    PubMed Central

    Varghese, Bright; Enani, Mushira; Shoukri, Mohammed; AlThawadi, Sahar; AlJohani, Sameera; Al- Hajoj, Sahal

    2017-01-01

    Background Clinical relevance of nontuberculous mycobacteria (NTM) is increasing worldwide including in Saudi Arabia. A high species diversity of NTM’s has been noticed in a recent study. However, the identification in diagnostic laboratories is mostly limited to common species. The impact of NTM species diversity on clinical outcome is so far neglected in most of the clinical settings. Methodology/Principal Findings During April 2014 to September 2015, a nationwide collection of suspected NTM clinical isolates with clinical and demographical data were carried out. Primary identification was performed by commercial line probe assays. Isolates identified up to Mycobacterium species level by line probe assays only were included and subjected to sequencing of 16S rRNA, rpoB, hsp65 and 16S-23S ITS region genes. The sequence data were subjected to BLAST analysis in GenBank and Ez-Taxon databases. Male Saudi nationals were dominated in the study population and falling majorly into the 46–59 years age group. Pulmonary cases were 59.3% with a surprising clinical relevance of 75% based on American Thoracic Society guidelines. Among the 40.7% extra-pulmonary cases, 50% of them were skin infections. The identification revealed 16 species and all of them are reporting for the first time in Saudi Arabia. The major species obtained were Mycobacterium monascence (18.5%), M. cosmeticum (11.1%), M. kubicae (11.1%), M. duvalli (7.4%), M.terrae (7.4%) and M. triplex (7.4%). This is the first report on clinical relevance of M. kubicae, M. tusciae, M.yongonense, M. arupense and M.iranicum causing pulmonary disease and M. monascence, M. duvalli, M. perigrinum, M. insubricum, M. holsaticum and M. kyorinense causing various extra-pulmonary diseases in Saudi Arabia. Ascites caused by M. monascence and cecum infection by M. holsaticum were the rarest incidents. Conclusions/Significance To the first time in the country, clinical significance of various rare NTM’s are well explored and

  14. Novel staphylococcal species that form part of a Staphylococcus aureus-related complex: the non-pigmented Staphylococcus argenteus sp. nov. and the non-human primate-associated Staphylococcus schweitzeri sp. nov.

    PubMed

    Tong, Steven Y C; Schaumburg, Frieder; Ellington, Matthew J; Corander, Jukka; Pichon, Bruno; Leendertz, Fabian; Bentley, Stephen D; Parkhill, Julian; Holt, Deborah C; Peters, Georg; Giffard, Philip M

    2015-01-01

    We define two novel species of the genus Staphylococcus that are phenotypically similar to and have near identical 16S rRNA gene sequences to Staphylococcus aureus. However, compared to S. aureus and each other, the two species, Staphylococcus argenteus sp. nov. (type strain MSHR1132(T) = DSM 28299(T) = SSI 89.005(T)) and Staphylococcus schweitzeri sp. nov. (type strain FSA084(T) = DSM 28300(T) = SSI 89.004(T)), demonstrate: 1) at a whole-genome level considerable phylogenetic distance, lack of admixture, average nucleotide identity <95 %, and inferred DNA-DNA hybridization <70 %; 2) different profiles as determined by MALDI-TOF MS; 3) a non-pigmented phenotype for S. argenteus sp. nov.; 4) S. schweitzeri sp. nov. is not detected by standard nucA PCR; 5) distinct peptidoglycan types compared to S. aureus; 6) a separate ecological niche for S. schweitzeri sp. nov.; and 7) a distinct clinical disease profile for S. argenteus sp. nov. compared to S. aureus.

  15. Novel staphylococcal species that form part of a Staphylococcus aureus-related complex: the non-pigmented Staphylococcus argenteus sp. nov. and the non-human primate-associated Staphylococcus schweitzeri sp. nov.

    PubMed Central

    Schaumburg, Frieder; Ellington, Matthew J.; Corander, Jukka; Pichon, Bruno; Leendertz, Fabian; Bentley, Stephen D.; Parkhill, Julian; Holt, Deborah C.; Peters, Georg; Giffard, Philip M.

    2015-01-01

    We define two novel species of the genus Staphylococcusthat are phenotypically similar to and have near identical 16S rRNA gene sequences to Staphylococcus aureus. However, compared to S. aureus and each other, the two species, Staphylococcus argenteus sp. nov. (type strain MSHR1132T = DSM 28299T = SSI 89.005T) and Staphylococcus schweitzeri sp. nov. (type strain FSA084T = DSM 28300T = SSI 89.004T), demonstrate: 1) at a whole-genome level considerable phylogenetic distance, lack of admixture, average nucleotide identity <95 %, and inferred DNA–DNA hybridization <70 %; 2) different profiles as determined by MALDI-TOF MS; 3) a non-pigmented phenotype for S. argenteus sp. nov.; 4) S. schweitzeri sp. nov. is not detected by standard nucA PCR; 5) distinct peptidoglycan types compared to S. aureus; 6) a separate ecological niche for S. schweitzeri sp. nov.; and 7) a distinct clinical disease profile for S. argenteus sp. nov. compared to S. aureus. PMID:25269845

  16. In vitro evaluation of single- and multi-strain probiotics: Inter-species inhibition between probiotic strains, and inhibition of pathogens.

    PubMed

    Chapman, C M C; Gibson, G R; Rowland, I

    2012-08-01

    Many studies comparing the effects of single- and multi-strain probiotics on pathogen inhibition compare treatments with different concentrations. They also do not examine the possibility of inhibition between probiotic strains with a mixture. We tested the ability of 14 single-species probiotics to inhibit each other using a cross-streak assay, and agar spot test. We then tested the ability of 15 single-species probiotics and 5 probiotic mixtures to inhibit Clostridium difficile, Escherichia coli and S. typhimurium, using the agar spot test. Testing was done with mixtures created in two ways: one group contained component species incubated together, the other group of mixtures was made using component species which had been incubated separately, equalised to equal optical density, and then mixed in equal volumes. Inhibition was observed for all combinations of probiotics, suggesting that when used as such there may be inhibition between probiotics, potentially reducing efficacy of the mixture. Significant inter-species variation was seen against each pathogen. When single species were tested against mixtures, the multi-species preparations displayed significantly (p < 0.05 or less) greater inhibition of pathogens in 12 out of 24 cases. Despite evidence that probiotic species will inhibit each other when incubated together in vitro, in many cases a probiotic mixture was more effective at inhibiting pathogens than its component species when tested at approximately equal concentrations of biomass. This suggests that using a probiotic mixture might be more effective at reducing gastrointestinal infections, and that creating a mixture using species with different effects against different pathogens may have a broader spectrum of action that a single provided by a single strain.

  17. AFM-Based Single Molecule Techniques: Unraveling the Amyloid Pathogenic Species

    PubMed Central

    Ruggeri, Francesco Simone; Habchi, Johnny; Cerreta, Andrea; Dietler, Giovanni

    2016-01-01

    Background A wide class of human diseases and neurodegenerative disorders, such as Alzheimer’s disease, is due to the failure of a specific peptide or protein to keep its native functional conformational state and to undergo a conformational change into a misfolded state, triggering the formation of fibrillar cross-β sheet amyloid aggregates. During the fibrillization, several coexisting species are formed, giving rise to a highly heterogeneous mixture. Despite its fundamental role in biological function and malfunction, the mechanism of protein self-assembly and the fundamental origins of the connection between aggregation, cellular toxicity and the biochemistry of neurodegeneration remains challenging to elucidate in molecular detail. In particular, the nature of the specific state of proteins that is most prone to cause cytotoxicity is not established. Methods: In the present review, we present the latest advances obtained by Atomic Force Microscopy (AFM) based techniques to unravel the biophysical properties of amyloid aggregates at the nanoscale. Unraveling amyloid single species biophysical properties still represents a formidable experimental challenge, mainly because of their nanoscale dimensions and heterogeneous nature. Bulk techniques, such as circular dichroism or infrared spectroscopy, are not able to characterize the heterogeneity and inner properties of amyloid aggregates at the single species level, preventing a profound investigation of the correlation between the biophysical properties and toxicity of the individual species. Conclusion: The information delivered by AFM based techniques could be central to study the aggregation pathway of proteins and to design molecules that could interfere with amyloid aggregation delaying the onset of misfolding diseases. PMID:27189600

  18. Wildly Growing Asparagus (Asparagus officinalis L.) Hosts Pathogenic Fusarium Species and Accumulates Their Mycotoxins.

    PubMed

    Stępień, Łukasz; Waśkiewicz, Agnieszka; Urbaniak, Monika

    2016-05-01

    Asparagus officinalis L. is an important crop in many European countries, likely infected by a number of Fusarium species. Most of them produce mycotoxins in plant tissues, thus affecting the physiology of the host plant. However, there is lack of information on Fusarium communities in wild asparagus, where they would definitely have considerable environmental significance. Therefore, the main scientific aim of this study was to identify the Fusarium species and quantify their typical mycotoxins present in wild asparagus plants collected at four time points of the season. Forty-four Fusarium strains of eight species--Fusarium acuminatum, Fusarium avenaceum, Fusarium culmorum, Fusarium equiseti, Fusarium oxysporum, Fusarium proliferatum, Fusarium sporotrichioides, and Fusarium tricinctum--were isolated from nine wild asparagus plants in 2013 season. It is the first report of F. sporotrichioides isolated from this particular host. Fumonisin B1 was the most abundant mycotoxin, and the highest concentrations of fumonisins B1-B3 and beauvericin were found in the spears collected in May. Moniliformin and enniatins were quantified at lower concentrations. Mycotoxins synthesized by individual strains obtained from infected asparagus tissues were assessed using in vitro cultures on sterile rice grain. Most of the F. sporotrichioides strains synthesized HT-2 toxin and F. equiseti strains were found to be effective zearalenone producers.

  19. Molecular analysis and pathogenicity of the Cladophialophora carrionii complex, with the description of a novel species

    PubMed Central

    de Hoog, G.S.; Nishikaku, A.S.; Fernandez-Zeppenfeldt, G.; Padín-González, C.; Burger, E.; Badali, H.; Richard-Yegres, N.; van den Ende, A.H.G. Gerrits

    2007-01-01

    Cladophialophora carrionii is one of the four major etiologic agents of human chromoblastomycosis in semi-arid climates. This species was studied using sequence data of the internal transcribed spacer region of rDNA, the partial β-tubulin gene and an intron in the translation elongation factor 1-alpha gene, in addition to morphology. With all genes a clear bipartition was observed, which corresponded with minute differences in conidiophore morphology. A new species, C. yegresii, was introduced, which appeared to be, in contrast to C. carrionii, associated with living cactus plants. All strains from humans, and a few isolates from dead cactus debris, belonged to C. carrionii, for which a lectotype was designated. Artificial inoculation of cactus plants grown from seeds in the greenhouse showed that both fungi are able to persist in cactus tissue. When reaching the spines they produce cells that morphologically resemble the muriform cells known as the “invasive form” in chromoblastomycosis. The tested clinical strain of C. carrionii proved to be more virulent in cactus than the environmental strain of C. yegresii that originated from the same species of cactus, Stenocereus griseus. The muriform cell expressed in cactus spines can be regarded as the extremotolerant survival phase, and is likely to play an essential role in the natural life cycle of these organisms. PMID:18491001

  20. Experimental hematogenous candidiasis caused by Candida krusei and Candida albicans: species differences in pathogenicity.

    PubMed Central

    Anaissie, E; Hachem, R; K-Tin-U, C; Stephens, L C; Bodey, G P

    1993-01-01

    Hematogenous infections caused by Candida krusei have been noted with increasing frequency, particularly in cancer patients receiving prophylaxis with antifungal triazoles. Progress in understanding the pathogenesis of this emerging infection has been limited by the lack of an animal model. We developed a CF1 mouse intravenous inoculation model of candidiasis to evaluate the pathogenicity of C. krusei in normal and immunosuppressed mice and to compare it with that of Candida albicans. Several inocula (10(6) to 10(8) CFU per animal) of two clinical strains of C. krusei and three American Type Culture Collection strains of C. albicans were tested. Groups of 20 mice each were injected with a single intravenous dose of one inoculum. Animals randomized to receive C. krusei were immunosuppressed by intraperitoneal injection of cyclophosphamide or the combination of cyclophosphamide plus cortisone acetate or they did not receive immunosuppressive agents (normal mice). One hundred percent mortality was observed in normal mice injected with 10(6) CFU of C. albicans per mouse compared with no mortality in normal mice that received 10(8) CFU of C. krusei per mouse (P < 0.01). Resistance to C. krusei infection was markedly lowered by immunosuppression, particularly by the combination of cyclophosphamide plus cortisone acetate, with a significantly shorter survival and a higher organ fungal burden in immunosuppressed than in normal animals (P < 0.01). Tissue infection was documented by culture and histopathologic findings in all examined organs. Images PMID:8454330

  1. Modulation of Stat-1 in Human Macrophages Infected with Different Species of Intracellular Pathogenic Bacteria

    PubMed Central

    Dominici, Sabrina; Rinaldi, Laura; Cangiano, Alfonsina Mariarosaria; Brandi, Giorgio; Magnani, Mauro

    2016-01-01

    The infection of human macrophages by pathogenic bacteria induces different signaling pathways depending on the type of cellular receptors involved in the microorganism entry and on their mechanism(s) of survival and replication in the host cell. It was reported that Stat proteins play an important role in this process. In the present study, we investigate the changes in Stat-1 activation (phosphorylation in p-tyr701) after uptake of two Gram-positive (Listeria monocytogenes and Staphylococcus aureus) and two Gram-negative bacteria (Salmonella typhimurium and Legionella pneumophila) characterized by their varying abilities to enter, survive, and replicate in human macrophages. Comparing the results obtained with Gram-negative and Gram-positive bacteria, Stat-1 activation in macrophages does not seem to be related to LPS content. The p-tyr701Stat-1 expression levels were found to be independent of the internalized bacterial number and IFN-γ release. On the contrary, Jak/Stat-1 pathway activation only occurs when an active infection has been established in the host macrophage, and it is plausible that the differences in the expression levels of p-tyr701Stat-1 could be due to different survival mechanisms or to differences in bacteria life cycles within macrophages. PMID:27437406

  2. Extracellular vesicles from Paracoccidioides pathogenic species transport polysaccharide and expose ligands for DC-SIGN receptors

    DOE PAGES

    da Silva, Roberta Peres; Heiss, Christian; Black, Ian; ...

    2015-09-21

    Extracellular vesicles (EVs) mediate non-conventional transport of molecules across the fungal cell wall. We aimed at describing the carbohydrate composition and surface carbohydrate epitopes of EVs isolated from the pathogenic fungi Paracoccidioides brasiliensis and P. lutzii using standard procedures. Total EV carbohydrates were ethanol-precipitated from preparations depleted of lipids and proteins, then analyzed by chemical degradation, gas chromatography-mass spectrometry, nuclear magnetic resonance and size-exclusion chromatography. EV glycosyl residues of Glc, Man, and Gal comprised most probably two major components: a high molecular mass 4,6-α-glucan and a galactofuranosylmannan, possibly an oligomer, bearing a 2-α-Manp main chain linked to β-Galf (1,3) andmore » α-Manp (1,6) end units. The results also suggested the presence of small amounts of a (1→6)- Manp polymer, (1→3)-glucan and (1→6)-glucan. Glycan microarrays allowed identification of EV surface lectin(s), while plant lectin microarray profiling revealed terminal Man and GlcNAc residues exposed at the EVs surface. Mammalian lectin microarray profiling showed that DC-SIGN receptors recognized surface carbohydrate in Paracoccidioides EVs. Our results suggest that oligosaccharides, cytoplasmic storage, and cell wall polysaccharides can be exported in fungal EVs, which also expose surface PAMPs and lectins. As a result, the role of these newly identified components in the interaction with the host remains to be unraveled.« less

  3. Measuring protein kinase and sugar kinase activity in plant pathogenic fusarium species.

    PubMed

    Bluhm, Burton H; Zhao, Xinhua

    2010-01-01

    As ubiquitous metabolic and signaling intermediaries, kinases regulate innumerable aspects of fungal growth and development. At its simplest, the enzymatic function of a kinase is to transfer a phosphate from a donor molecule (such as adenosine triphosphate) to an acceptor molecule, such as a protein, carbohydrate, or lipid. Kinase activity is intricately interwoven into signal transduction, and ultimately modulates gene expression, downstream phosphorylation events, and other mechanisms of posttranslational modification. Therefore, sensitive and reproducible techniques to measure kinase activity are crucial to elucidate cellular signaling and for fungal functional genomics.Protein and sugar kinases regulate multiple aspects of pathogenesis in the mycotoxigenic, plant pathogenic fungi Fusarium graminearum, and Fusarium verticillioides. Here, we present protocols to (1) quantify phosphorylation of mitogen-activated protein kinases in F. graminearum, and (2) determine glucokinase activity in F. verticillioides. The mitogen-activated protein kinase phosphorylation assay utilizes immunological methods to quantify substrate phosphorylation, whereas the glucokinase assay is a coupled enzyme assay, in which phosphorylation of glucose by glucokinase is measured indirectly through the subsequent reduction of NADP+ to NADPH, a substrate more amenable for spectrophotometric detection.

  4. In silico serine β-lactamases analysis reveals a huge potential resistome in environmental and pathogenic species

    PubMed Central

    Brandt, Christian; Braun, Sascha D.; Stein, Claudia; Slickers, Peter; Ehricht, Ralf; Pletz, Mathias W.; Makarewicz, Oliwia

    2017-01-01

    The secretion of antimicrobial compounds is an ancient mechanism with clear survival benefits for microbes competing with other microorganisms. Consequently, mechanisms that confer resistance are also ancient and may represent an underestimated reservoir in environmental bacteria. In this context, β-lactamases (BLs) are of great interest due to their long-term presence and diversification in the hospital environment, leading to the emergence of Gram-negative pathogens that are resistant to cephalosporins (extended spectrum BLs = ESBLs) and carbapenems (carbapenemases). In the current study, protein sequence databases were used to analyze BLs, and the results revealed a substantial number of unknown and functionally uncharacterized BLs in a multitude of environmental and pathogenic species. Together, these BLs represent an uncharacterized reservoir of potentially transferable resistance genes. Considering all available data, in silico approaches appear to more adequately reflect a given resistome than analyses of limited datasets. This approach leads to a more precise definition of BL clades and conserved motifs. Moreover, it may support the prediction of new resistance determinants and improve the tailored development of robust molecular diagnostics. PMID:28233789

  5. Photodynamic inactivation of pathogenic species Pseudomonas aeruginosa and Candida albicans with lutetium (III) acetate phthalocyanines and specific light irradiation.

    PubMed

    Mantareva, Vanya; Kussovski, Vesselin; Durmuş, Mahmut; Borisova, Ekaterina; Angelov, Ivan

    2016-11-01

    Photodynamic inactivation (PDI) is a light-associated therapeutic approach suitable for treatment of local acute infections. The method is based on specific light-activated compound which by specific irradiation and in the presence of molecular oxygen produced molecular singlet oxygen and other reactive oxygen species, all toxic for pathogenic microbial cells. The study presents photodynamic impact of two recently synthesized water-soluble cationic lutetium (III) acetate phthalocyanines (LuPc-5 and LuPc-6) towards two pathogenic strains, namely, the Gram-negative bacterium Pseudomonas aeruginosa and a fungus Candida albicans. The photodynamic effect was evaluated for the cells in suspensions and organized in 48-h developed biofilms. The relatively high levels of uptakes of LuPc-5 and LuPc-6 were determined for fungal cells compared to bacterial cells. The penetration depths and distribution of both LuPcs into microbial biofilms were investigated by means of confocal fluorescence microscopy. The photoinactivation efficiency was studied for a wide concentration range (0.85-30 μM) of LuPc-5 and LuPc-6 at a light dose of 50 J cm(-2) from red light-emitting diode (LED; 665 nm). The PDI study on microbial biofilms showed incomplete photoinactivation (<3 logs) for the used gentle drug-light protocol.

  6. Revisiting the reference genomes of human pathogenic Cryptosporidium species: reannotation of C. parvum Iowa and a new C. hominis reference.

    PubMed

    Isaza, Juan P; Galván, Ana Luz; Polanco, Victor; Huang, Bernice; Matveyev, Andrey V; Serrano, Myrna G; Manque, Patricio; Buck, Gregory A; Alzate, Juan F

    2015-11-09

    Cryptosporidium parvum and C. hominis are the most relevant species of this genus for human health. Both cause a self-limiting diarrhea in immunocompetent individuals, but cause potentially life-threatening disease in the immunocompromised. Despite the importance of these pathogens, only one reference genome of each has been analyzed and published. These two reference genomes were sequenced using automated capillary sequencing; as of yet, no next generation sequencing technology has been applied to improve their assemblies and annotations. For C. hominis, the main challenge that prevents a larger number of genomes to be sequenced is its resistance to axenic culture. In the present study, we employed next generation technology to analyse the genomic DNA and RNA to generate a new reference genome sequence of a C. hominis strain isolated directly from human stool and a new genome annotation of the C. parvum Iowa reference genome.

  7. Revisiting the reference genomes of human pathogenic Cryptosporidium species: reannotation of C. parvum Iowa and a new C. hominis reference

    PubMed Central

    Isaza, Juan P.; Galván, Ana Luz; Polanco, Victor; Huang, Bernice; Matveyev, Andrey V.; Serrano, Myrna G.; Manque, Patricio; Buck, Gregory A.; Alzate, Juan F.

    2015-01-01

    Cryptosporidium parvum and C. hominis are the most relevant species of this genus for human health. Both cause a self-limiting diarrhea in immunocompetent individuals, but cause potentially life-threatening disease in the immunocompromised. Despite the importance of these pathogens, only one reference genome of each has been analyzed and published. These two reference genomes were sequenced using automated capillary sequencing; as of yet, no next generation sequencing technology has been applied to improve their assemblies and annotations. For C. hominis, the main challenge that prevents a larger number of genomes to be sequenced is its resistance to axenic culture. In the present study, we employed next generation technology to analyse the genomic DNA and RNA to generate a new reference genome sequence of a C. hominis strain isolated directly from human stool and a new genome annotation of the C. parvum Iowa reference genome. PMID:26549794

  8. A Proteomic Approach Provides New Insights into the Control of Soil-Borne Plant Pathogens by Bacillus Species

    PubMed Central

    Xu, Han-Hong; Siragusa, Mirko; Çalışkan, Mikail; Carimi, Francesco; da Silva, Jaime A. Teixeira.; Tör, Mahmut

    2013-01-01

    Beneficial microorganisms (also known as biopesticides) are considered to be one of the most promising methods for more rational and safe crop management practices. We used Bacillus strains EU07, QST713 and FZB24, and investigated their inhibitory effect on Fusarium. Bacterial cell cultures, cell-free supernatants and volatiles displayed varying degrees of suppressive effect. Proteomic analysis of secreted proteins from EU07 and FZB24 revealed the presence of lytic enzymes, cellulases, proteases, 1,4-β-glucanase and hydrolases, all of which contribute to degradation of the pathogen cell wall. Further proteomic investigations showed that proteins involved in metabolism, protein folding, protein degradation, translation, recognition and signal transduction cascade play an important role in the control of Fusarium oxysporum. Our findings provide new knowledge on the mechanism of action of Bacillus species and insight into biocontrol mechanisms. PMID:23301041

  9. Evidence of land-sea transfer of the zoonotic pathogen Campylobacter to a wildlife marine sentinel species.

    PubMed

    Baily, Johanna L; Méric, Guillaume; Bayliss, Sion; Foster, Geoffrey; Moss, Simon E; Watson, Eleanor; Pascoe, Ben; Mikhail, Jane; Pizzi, Romain; Goldstone, Robert J; Smith, David G E; Willoughby, Kim; Hall, Ailsa J; Sheppard, Samuel K; Dagleish, Mark P

    2015-01-01

    Environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. Here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. The common zoonotic bacterium Campylobacter was isolated from grey seals (Halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild birds, agricultural sources and clinical samples to characterize possible transmission routes. Campylobacter jejuni was present in half of all grey seal pups sampled (24/50 dead and 46/90 live pups) in the breeding colony on the Isle of May (Scotland), where it was frequently associated with histological evidence of disease. Returning yearling animals (19/19) were negative for C. jejuni suggesting clearance of infection while away from the localized colony infection source. The genomes of 90 isolates from seals were sequenced and characterized using a whole-genome multilocus sequence typing (MLST) approach and compared to 192 published genomes from multiple sources using population genetic approaches and a probabilistic genetic attribution model to infer the source of infection from MLST data. The strong genotype-host association has enabled the application of source attribution models in epidemiological studies of human campylobacteriosis, and here assignment analyses consistently grouped seal isolates with those from human clinical samples. These findings are consistent with either a common infection source or direct transmission of human campylobacter to grey seals, raising concerns about the spread of human pathogens to wildlife marine sentinel species in coastal areas.

  10. Species-specific activation of Cu/Zn SOD by its CCS copper chaperone in the pathogenic yeast Candida albicans

    PubMed Central

    Gleason, Julie E.; Li, Cissy X; Odeh, Hana M.; Culotta, Valeria C.

    2013-01-01

    Candida albicans is a pathogenic yeast of important public health relevance. Virulence of C. albicans requires a copper and zinc containing superoxide dismutase (SOD1), but the biology of C. albicans SOD1 is poorly understood. To this end, C. albicans SOD1 activation was examined in baker’s yeast (Saccharomyces cerevisiae), a eukaryotic expression system proven fruitful for the study of Cu/Zn SODs from invertebrates, plants and mammals. In spite of the 80% similarity between S. cerevisiae and C. albicans SOD1 molecules, C. albicans SOD1 is not active in S. cerevisiae. The SOD1 appears incapable of productive interactions with the copper chaperone for SOD1 (CCS1) of baker’s yeast. C. albicans SOD1 contains a proline at position 144 predicted to dictate dependence on CCS1. By mutating this proline, C. albicans SOD1 gained activity in baker’s yeast and this activity was independent of CCS1. We identified a putative CCS1 gene in C. albicans and created heterozygous and homozygous gene deletions at this locus. Loss of CCS1 resulted in loss of SOD1 activity, consistent with its role as a copper chaperone. C. albicans CCS1 also restored activity to C. albicans SOD1 expressed in baker’s yeast. C. albicans CCS1 is well adapted for activating its partner SOD1 from C. albicans, but not SOD1 from S. cerevisiae. In spite of the high degree of homology between the SOD1 and CCS1 molecules in these two fungal species, there exists a specie-specific barrier in CCS-SOD interactions which may reflect the vastly different lifestyles of the pathogenic versus non-infectious yeast. PMID:24043471

  11. Pathogenic Candida species differ in the ability to grow at limiting potassium concentrations.

    PubMed

    Hušeková, B; Elicharová, H; Sychrová, H

    2016-05-01

    A high intracellular concentration of potassium (200-300 mmol/L) is essential for many yeast cell functions, such as the regulation of cell volume and pH, maintenance of membrane potential, and enzyme activation. Thus, cells use high-affinity specific transporters and expend a lot of energy to acquire the necessary amount of potassium from their environment. In Candida genomes, genes encoding 3 types of putative potassium uptake systems were identified: Trk uniporters, Hak symporters, and Acu ATPases. Tests of the tolerance and sensitivity of C. albicans, C. dubliniensis, C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis to various concentrations of potassium showed significant differences among the species, and these differences were partly dependent on external pH. The species most tolerant to potassium-limiting conditions were C. albicans and C. krusei, while C. parapsilosis tolerated the highest KCl concentrations. Also, the morphology of cells changed with the amount of potassium available, with C. krusei and C. tropicalis being the most influenced. Taken together, our results confirm potassium uptake and accumulation as important factors for Candida cell growth and suggest that the sole (and thus probably indispensable) Trk1 potassium uptake system in C. krusei and C. glabrata may serve as a target for the development of new antifungal drugs.

  12. Genome sequence of a pathogenic isolate of monkey B virus (species Macacine herpesvirus 1).

    PubMed

    Ohsawa, Kazutaka; Black, Darla; Ohsawa, Makiko; Eberle, R

    2014-10-01

    The only genome sequence for monkey B virus (BV; species Macacine herpesvirus 1) is that of an attenuated vaccine strain originally isolated from a rhesus monkey (BVrh). Here we report the genome sequence of a virulent BV strain isolated from a cynomolgus macaque (BVcy). The overall genome organization is the same, although sequence differences exist. The greatest sequence divergence is located in non-coding areas of the long and short repeat regions. Like BVrh, BVcy has duplicated Ori elements and lacks an ORF corresponding to the γ34.5 gene of herpes simplex virus. Nine of ten miRNAs and the majority of ORFs are conserved between BVrh and BVcy. The most divergent genes are several membrane-associated proteins and those encoding immediate early proteins.

  13. Effects of twenty-five compounds on four species of aquatic fungi (Saprolegniales) pathogenic to fish

    USGS Publications Warehouse

    Bailey, T.A.

    1984-01-01

    Four species of aquatic fungi (Achlya flagellata, A. racemosa, Saprolegnia hypogyna, and S. megasperma) were exposed to 25 chemicals representing seven classes of compounds for 15 and 60 min, in an effort to identify potential fungicidal agents for use in fish culture. The antifungal activity of each chemical was compared with that of malachite green, a reference compound with known fungicidal properties but not registered for fishery use. Six compounds which inhibited fungal growth on artificial media at concentrations of < 100 mg/l (listed in order of decreasing antifungal activity) were the cationics Du-terA? and copper oxychloride sulfate, the amine LesanA?, the amide BAS-389-O1F and the cationics CuprimyxinA? and RoccalA? II. Certain chemicals from these classes of compounds may have promise as aquatic fungicides.

  14. Mapping the Pathways to Staphylococcal Pathogenesis by Comparative Secretomics

    PubMed Central

    Sibbald, M. J. J. B.; Ziebandt, A. K.; Engelmann, S.; Hecker, M.; de Jong, A.; Harmsen, H. J. M.; Raangs, G. C.; Stokroos, I.; Arends, J. P.; Dubois, J. Y. F.; van Dijl, J. M.

    2006-01-01

    The gram-positive bacterium Staphylococcus aureus is a frequent component of the human microbial flora that can turn into a dangerous pathogen. As such, this organism is capable of infecting almost every tissue and organ system in the human body. It does so by actively exporting a variety of virulence factors to the cell surface and extracellular milieu. Upon reaching their respective destinations, these virulence factors have pivotal roles in the colonization and subversion of the human host. It is therefore of major importance to obtain a clear understanding of the protein transport pathways that are active in S. aureus. The present review aims to provide a state-of-the-art roadmap of staphylococcal secretomes, which include both protein transport pathways and the extracytoplasmic proteins of these organisms. Specifically, an overview is presented of the exported virulence factors, pathways for protein transport, signals for cellular protein retention or secretion, and the exoproteomes of different S. aureus isolates. The focus is on S. aureus, but comparisons with Staphylococcus epidermidis and other gram-positive bacteria, such as Bacillus subtilis, are included where appropriate. Importantly, the results of genomic and proteomic studies on S. aureus secretomes are integrated through a comparative “secretomics” approach, resulting in the first definition of the core and variant secretomes of this bacterium. While the core secretome seems to be largely employed for general housekeeping functions which are necessary to thrive in particular niches provided by the human host, the variant secretome seems to contain the “gadgets” that S. aureus needs to conquer these well-protected niches. PMID:16959968

  15. Characterization of a new pathogenic Acanthamoeba Species, A. byersi n. sp., isolated from a human with fatal amoebic encephalitis.

    PubMed

    Qvarnstrom, Yvonne; Nerad, Thomas A; Visvesvara, Govinda S

    2013-01-01

    Acanthamoeba spp. are free-living amoebae that are ubiquitous in natural environments. They can cause cutaneous, nasopharyngeal, and disseminated infection, leading to granulomatous amebic encephalitis (GAE) in immunocompromised individuals. In addition, they can cause amoebic keratitis in contact lens wearers. Acanthamoeba GAE is almost always fatal because of difficulty and delay in diagnosis and lack of optimal antimicrobial therapy. Here, we report the description of an unusual strain isolated from skin and brain of a GAE patient. The amoebae displayed large trophozoites and star-shaped cysts, characteristics for acanthamoebas belonging to morphology Group 1. However, its unique morphology and growth characteristics differentiated this new strain from other Group 1 species. DNA sequence analysis, secondary structure prediction, and phylogenetic analysis of the 18S rRNA gene confirmed that this new strain belonged to Group 1, but that it was distinct from the other sequence types within that group. Thus, we hereby propose the establishment of a new species, Acanthamoeba byersi n. sp. as well as a new sequence type, T18, for this new strain. To our knowledge, this is the first report of a Group 1 Acanthamoeba that is indisputably pathogenic in humans.

  16. Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species.

    PubMed

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

    2008-01-01

    Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species.

  17. Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species

    PubMed Central

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

    2008-01-01

    Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species. PMID:24031186

  18. Specificity of antigens from pathogenic Aspergillus species. I. Studies with ELISA and immunofluorescence.

    PubMed

    De Magaldi, S W; Mackenzie, D W

    1984-01-01

    Studies were made by enzyme linked immunosorbent assay (ELISA) and indirect fluorescent antibody (IFA) tests on the reactivities and specificities of 13 antigens prepared from four species of Aspergillus against antisera from immunized rabbits and 64 sera from patients with aspergillosis, other systemic mycoses and nocardiosis. Although reactions in both serological tests were invariably strongest with homologous antigen: antibody systems, antisera from rabbits immunized with A. fumigatus, Blastomyces dermatitidis, Candida albicans and Paracoccidioides brasiliensis reacted in the ELISA test with all of the Aspergillus antigens. In contrast, cross-reactivity was virtually non-existent with antiserum to Histoplasma capsulatum. Of five antigens prepared from A fumigatus tested by ELISA against human sera from patients with aspergillosis and other nocardial and systemic fungal infections, sensitivities varied from 81 to 100% for sera from 32 patients with aspergillosis, and specificities from 20 to 97% for sera from 30 patients with nocardiosis and other systemic mycoses. Purified A. fumigatus C antigen reacted weakly with sera from eight of these 30 patients, but the reactions were readily distinguishable from those obtained with sera from patients with aspergillosis. At optimal serum dilutions, cross-reactivities of A. fumigatus in the IFA studies were non-existent in the sera from 28 patients with candidosis, coccidioidomycosis, cryptococcosis, histoplasmosis, paracoccidioidomycosis and nocardiosis. Sensitivities of IFA were 94% for patients with aspergilloma and 83% for patients with allergic bronchopulmonary aspergillosis.

  19. River networks as ecological corridors for species, populations and pathogens of water-borne disease (Invited)

    NASA Astrophysics Data System (ADS)

    Rinaldo, A.; Bertuzzo, E.; Mari, L.; Suweis, S.; Ceola, S.; Carrara, F.; Rodriguez-Iturbe, I.

    2010-12-01

    Recent works at the interface of hydrology, geomorphology and ecology under an integrated framework of analysis will be reviewed with a view to a general theory for reactive transport on networks. A number of related topics will be reviewed, linked by the characters of stochastic transport, and the networked environmental matrix (including biodiversity of freshwater fish in river networks and vegetation along riparian systems, how river networks affected historic spreading of human populations, and how they influence the spreading of water-borne disease). The unique, coherent ecohydrological thread and similar mathematical methods will be exposed. Metacommunity and individual-based models will be described in the contexts of hydrochory, population and species migrations, and the spreading of infections of water-borne disease along the ecological corridors generated by the river basin. A general effect is shown to emerge on the effects of dendritic geometries on the ecological processes and dynamics operating on river basins. Insights provided by such a theory will lend themselves to issues of practical importance such as integration of riparian systems into large-scale resource management, spatial strategies to minimize loss of freshwater biodiversity, and effective prevention/vaccination campaigns against water-borne diseases.

  20. An investigation and evaluation on species and characteristics of pathogenic microorganisms in Chinese local hospital settings.

    PubMed

    Chen, Liang; Lü, Xiaoli; Cao, Weiping; Zhang, Chunxia; Xu, Rongfa; Meng, Xu; Chen, Keping

    2015-12-01

    There are currently great concerns about the level of bacterial contamination in hospitals, as well as resistance to antimicrobial agents. The species and characteristics of microbes in Chinese hospitals are closely related to healthcare safety and the prevention and control of infections. However, data on the exposure of patients to microbes in Chinese hospitals are limited. The present study investigated the genera of microorganisms in Chinese hospitals. We evaluated their characteristics, such as antibiotic susceptibility, tolerance to disinfectants, and toxicity, using silkworms (Bombyx mori) as an animal model. Twenty-six distinct bacterial strains were isolated, and their genera were determined by sequencing their 16S rDNA regions. Twenty-five strains were resistant to one or more antibiotics, and six strains were resistant to multiple antibiotics. The results of minimal inhibitory concentration testing showed that eight strains were resistant to a chlorine-containing disinfectant, and 12 strains were resistant to Povidone-iodine. Following the injection of bacterial cultures into the silkworm hemolymph, 15 strains killed all of the silkworms within 5 d. Additionally, bacterial strain 14 killed all of silkworms within 12 h with a median lethal dose of 4 × 10(4) colony-forming units/larva. This study provides useful information for healthcare safety in Chinese hospitals.

  1. Pulsed light for the inactivation of fungal biofilms of clinically important pathogenic Candida species.

    PubMed

    Garvey, Mary; Andrade Fernandes, Joao Paulo; Rowan, Neil

    2015-07-01

    Microorganisms are naturally found as biofilm communities more than planktonic free-floating cells; however, planktonic culture remains the current model for microbiological studies, such as disinfection techniques. The presence of fungal biofilms in the clinical setting has a negative impact on patient mortality, as Candida biofilms have proved to be resistant to biocides in numerous in vitro studies; however, there is limited information on the effect of pulsed light on sessile communities. Here we report on the use of pulsed UV light for the effective inactivation of clinically relevant Candida species. Fungal biofilms were grown by use of a CDC reactor on clinically relevant surfaces. Following a maximal 72 h formation period, the densely populated biofilms were exposed to pulsed light at varying fluences to determine biofilm sensitivity to pulsed-light inactivation. The results were then compared to planktonic cell inactivation. High levels of inactivation of C. albicans and C. parapsilosis biofilms were achieved with pulsed light for both 48 and 72 h biofilm structures. The findings suggest that pulsed light has the potential to provide a means of surface decontamination, subsequently reducing the risk of infection to patients. The research described herein deals with an important aspect of disease prevention and public health.

  2. Incidence of Salmonella, Listeria monocytogenes, Escherichia coli O157:H7, and Staphylococcal enterotoxin in two types of Mexican fresh cheeses.

    PubMed

    Torres-Vitela, M R; Mendoza-Bernardo, M; Castro-Rosas, J; Gomez-Aldapa, C A; Garay-Martinez, L E; Navarro-Hidalgo, V; Villarruel-López, A

    2012-01-01

    Handcrafted fresh cheeses are popular among consumers in Mexico. However, unsafe raw materials and inadequate food safety practices during cheese manufacture and preservation make them a potential public health risk. The incidence of Salmonella, Listeria, Escherichia coli O157:H7, and staphylococcal enterotoxin was analyzed in two types of fresh cheese (panela and adobera) commonly marketed in Mexico. A total of 200 samples, 100 panela and 100 adobera, were acquired from 100 wholesale milk product distributors who supply small retailers in the Guadalajara metropolitan area, Jalisco State, Mexico. Pathogens were identified using culture and immunoassay (miniVidas) methods. The presence of staphylococcal enterotoxin was determined by an immunoassay method. Of the 200 analyzed samples, 92 were positive for at least one of the pathogens. The incidence in the panela samples was 56%: 34% Salmonella, 16% E. coli O157:H7, and 6% L. monocytogenes. In the adobera samples, incidence was 36%: 20% Salmonella, 4% E. coli O157:H7, and 12% L. monocytogenes. Staphylococcal enterotoxin was not detected in any of the 200 samples. Choice of technique had no effect on detection of pathogen incidence, although the immunoassay method identified more Salmonella serotypes than the culture method. Handcrafted panela and adobera fresh cheeses in Mexico frequently contain pathogenic bacteria and therefore pose a public health risk.

  3. Identification of Circular RNAs in Kiwifruit and Their Species-Specific Response to Bacterial Canker Pathogen Invasion

    PubMed Central

    Wang, Zupeng; Liu, Yifei; Li, Dawei; Li, Li; Zhang, Qiong; Wang, Shuaibin; Huang, Hongwen

    2017-01-01

    Research studies have recently focused on circle RNAs (circRNAs) in relation to their regulatory functions in animals. However, the systematic identification of circRNAs in plants, especially non-model plants, is limited. In addition, raw report on the prediction of the potential role of circRNAs in plant response to pathogen invasion is currently available. We conducted the systematic identification of circRNAs from four materials originating from three species belonging to genus Actinidia under different situations using ribosomal RNA (rRNA) depleted RNA-Seq data. A total of 3,582 circRNAs were identified in Actinidia, of which 64.01, 21.44, and 14.55% were intergenic circRNAs, exonic circRNAs, and intronic circRNAs, respectively. Tissue-specific expression of circRNAs was observed in kiwifruit, and a species-specific response was detected when infected with Pseudomonas syringae pv. actinidiae (Psa), which is the causative agent of kiwifruit bacterial canker disease. Furthermore, we found that both exonic and intronic circRNAs were significantly positively correlated to parent protein-coding genes, and intronic circRNAs are a class of highly remarkable regulators the parent genes comparing to that of exonic circRNAs. Expression and weighted gene co-expression network analysis (WGCNA) identified a set of circRNAs that were closely associated with plant defense response. The findings of the presents study suggest that circRNAs exhibit tissue- and species-specific expression, as well as play an important role in plant immune response.

  4. Contribution of Ultra Deep Sequencing in the Clinical Diagnosis of a New Fungal Pathogen Species: Basidiobolus meristosporus

    PubMed Central

    Sitterlé, Emilie; Rodriguez, Christophe; Mounier, Roman; Calderaro, Julien; Foulet, Françoise; Develoux, Michel; Pawlotsky, Jean-Michel; Botterel, Françoise

    2017-01-01

    Some cases of fungal infection remained undiagnosed, especially when the pathogens are uncommon, require specific conditions for in vitro growth, or when several microbial species are present in the specimen. Ultra-Deep Sequencing (UDS) could be considered as a precise tool in the identification of involved pathogens in order to upgrade patient treatment. In this study, we report the implementation of UDS technology in medical laboratory during the follow-up of an atypical fungal infection case. Thanks to UDS technology, we document the first case of gastro-intestinal basidiobolomycosis (GIB) due to Basidiobolus meristosporus. The diagnosis was suspected after histopathological examination but conventional microbiological methods failed to supply proof. The final diagnosis was made by means of an original approach based on UDS. DNA was extracted from the embedded colon biopsy obtained after hemicolectomy, and a fragment encompassing the internal transcribed spacer (ITS) rDNA region was PCR-amplified. An Amplicon library was then prepared using Genome Sequencer Junior Titanium Kits (Roche/454 Life Sciences) and the library was pyrosequenced on a GS Junior (Roche/454 Life Sciences). Using this method, 2,247 sequences with more than 100 bases were generated and used for UDS analysis. B. meristosporus represented 80% of the sequences, with an average homology of 98.8%. A phylogenetic tree with Basidiobolus reference sequences confirmed the presence of B. meristosporus (bootstrap value of 99%). Conclusion : UDS-based diagnostic approaches are ready to integrate conventional diagnostic testing to improve documentation of infectious disease and the therapeutic management of patients. PMID:28326064

  5. Contribution of Ultra Deep Sequencing in the Clinical Diagnosis of a New Fungal Pathogen Species: Basidiobolus meristosporus.

    PubMed

    Sitterlé, Emilie; Rodriguez, Christophe; Mounier, Roman; Calderaro, Julien; Foulet, Françoise; Develoux, Michel; Pawlotsky, Jean-Michel; Botterel, Françoise

    2017-01-01

    Some cases of fungal infection remained undiagnosed, especially when the pathogens are uncommon, require specific conditions for in vitro growth, or when several microbial species are present in the specimen. Ultra-Deep Sequencing (UDS) could be considered as a precise tool in the identification of involved pathogens in order to upgrade patient treatment. In this study, we report the implementation of UDS technology in medical laboratory during the follow-up of an atypical fungal infection case. Thanks to UDS technology, we document the first case of gastro-intestinal basidiobolomycosis (GIB) due to Basidiobolus meristosporus. The diagnosis was suspected after histopathological examination but conventional microbiological methods failed to supply proof. The final diagnosis was made by means of an original approach based on UDS. DNA was extracted from the embedded colon biopsy obtained after hemicolectomy, and a fragment encompassing the internal transcribed spacer (ITS) rDNA region was PCR-amplified. An Amplicon library was then prepared using Genome Sequencer Junior Titanium Kits (Roche/454 Life Sciences) and the library was pyrosequenced on a GS Junior (Roche/454 Life Sciences). Using this method, 2,247 sequences with more than 100 bases were generated and used for UDS analysis. B. meristosporus represented 80% of the sequences, with an average homology of 98.8%. A phylogenetic tree with Basidiobolus reference sequences confirmed the presence of B. meristosporus (bootstrap value of 99%). Conclusion : UDS-based diagnostic approaches are ready to integrate conventional diagnostic testing to improve documentation of infectious disease and the therapeutic management of patients.

  6. PCR primers for the detection of staphylococcal enterotoxins K, L, and M and survey of staphylococcal enterotoxin types in Staphylococcus aureus isolates from food poisoning cases in Taiwan.

    PubMed

    Chiang, Yu-Cheng; Chang, Li-Tung; Lin, Chia-Wei; Yang, Chi-Yea; Tsen, Hau-Yang

    2006-05-01

    Staphylococcal enterotoxins (SEs) are important causative agents in gastroenteritidis and food poisoning cases. They are serologically grouped into five major classical types, i.e., SEA, SEB, SEC, SED, and SEE. In addition, new SEs, such as SEG through SEM, have recently been identified and characterized. In an attempt to survey the distribution of classical and new SEs in organisms responsible for staphylococcal infections in Taiwan, we developed PCR primers for the genes that define the SEK, SEL, and SEM types. Bacterial strains other than sek, sel, and sem Staphylococcus aureus, including strains of other Staphylococcus species, did not generate any false-positive results when examined with these primers. The expression potential for the sek, sel, and sem types were also determined by reverse transcription-PCR. Together with the PCR primers specific for the classical SEs and other new SEs, including SEG, SEH, SEI, and SEJ, we surveyed the SE genes in S. aureus strains isolated from food poisoning cases. For 147 S. aureus isolates originating from food poisoning cases, 109 (74.1%) were positive for one or more SE genes. Of them, the major classical enterotoxin type was sea (28.6%), followed by seb (20.4%), sec (8.2%), and sed (2.0%). For the new SE types, sei (30.6%) was detected the most often, followed by sek (18.4%), sem (12.9%), and sel (8.2%). Also, 64 (43.5%) of the total bacterial strains had more than one enterotoxin gene.

  7. Interferon-γ Protects from Staphylococcal Alpha Toxin-Induced Keratinocyte Death through Apolipoprotein L1.

    PubMed

    Brauweiler, Anne M; Goleva, Elena; Leung, Donald Y M

    2016-03-01

    Staphylococcus aureus is a bacterial pathogen that frequently infects the skin, causing lesions and cell destruction through its primary virulence factor, alpha toxin. Here we show that interferon gamma (IFN-?) protects human keratinocytes from cell death induced by staphylococcal alpha toxin. We find that IFN-? prevents alpha toxin binding and reduces expression of the alpha toxin receptor, a disintegrin and metalloproteinase 10 (ADAM10). We determine that the mechanism for IFN-?-mediated resistance to alpha toxin involves the induction of autophagy, a process of cellular adaptation to sublethal damage. We find that IFN-? potently stimulates activation of the primary autophagy effector, light chain 3 (LC3). This process is dependent on upregulation of apolipoprotein L1. Depletion of apolipoprotein L1 by small interfering RNA significantly increases alpha toxin-induced lethality and inhibits activation of light chain 3. We conclude that IFN-? plays a significant role in protecting human keratinocytes from the lethal effects of staphylococcal alpha toxin through apolipoprotein L1-induced autophagy.

  8. Staphylococcus aureus and Staphylococcal Food-Borne Disease: An Ongoing Challenge in Public Health

    PubMed Central

    Smith, Tara C.

    2014-01-01

    Staphylococcal food-borne disease (SFD) is one of the most common food-borne diseases worldwide resulting from the contamination of food by preformed S. aureus enterotoxins. It is one of the most common causes of reported food-borne diseases in the United States. Although several Staphylococcal enterotoxins (SEs) have been identified, SEA, a highly heat-stable SE, is the most common cause of SFD worldwide. Outbreak investigations have found that improper food handling practices in the retail industry account for the majority of SFD outbreaks. However, several studies have documented prevalence of S. aureus in many food products including raw retail meat indicating that consumers are at potential risk of S. aureus colonization and subsequent infection. Presence of pathogens in food products imposes potential hazard for consumers and causes grave economic loss and loss in human productivity via food-borne disease. Symptoms of SFD include nausea, vomiting, and abdominal cramps with or without diarrhea. Preventive measures include safe food handling and processing practice, maintaining cold chain, adequate cleaning and disinfection of equipment, prevention of cross-contamination in home and kitchen, and prevention of contamination from farm to fork. This paper provides a brief overview of SFD, contributing factors, risk that it imposes to the consumers, current research gaps, and preventive measures. PMID:24804250

  9. Emerging Infectious Disease Implications of Invasive Mammalian Species: The Greater White-Toothed Shrew (Crocidura russula) Is Associated With a Novel Serovar of Pathogenic Leptospira in Ireland

    PubMed Central

    Nally, Jarlath E.; Arent, Zbigniew; Bayles, Darrell O.; Hornsby, Richard L.; Gilmore, Colm; Regan, Siobhan; McDevitt, Allan D.; Yearsley, Jon; Fanning, Séamus; McMahon, Barry J.

    2016-01-01

    The greater white-toothed shrew (Crocidura russula) is an invasive mammalian species that was first recorded in Ireland in 2007. It currently occupies an area of approximately 7,600 km2 on the island. C. russula is normally distributed in Northern Africa and Western Europe, and was previously absent from the British Isles. Whilst invasive species can have dramatic and rapid impacts on faunal and floral communities, they may also be carriers of pathogens facilitating disease transmission in potentially naive populations. Pathogenic leptospires are endemic in Ireland and a significant cause of human and animal disease. From 18 trapped C. russula, 3 isolates of Leptospira were cultured. However, typing of these isolates by standard serological reference methods was negative, and suggested an, as yet, unidentified serovar. Sequence analysis of 16S ribosomal RNA and secY indicated that these novel isolates belong to Leptospira alstonii, a unique pathogenic species of which only 7 isolates have been described to date. Earlier isolations were limited geographically to China, Japan and Malaysia, and this leptospiral species had not previously been cultured from mammals. Restriction enzyme analysis (REA) further confirms the novelty of these strains since no similar patterns were observed with a reference database of leptospires. As with other pathogenic Leptospira species, these isolates contain lipL32 and do not grow in the presence of 8-azagunaine; however no evidence of disease was apparent after experimental infection of hamsters. These isolates are genetically related to L. alstonii but have a novel REA pattern; they represent a new serovar which we designate as serovar Room22. This study demonstrates that invasive mammalian species act as bridge vectors of novel zoonotic pathogens such as Leptospira. PMID:27935961

  10. Emerging Infectious Disease Implications of Invasive Mammalian Species: The Greater White-Toothed Shrew (Crocidura russula) Is Associated With a Novel Serovar of Pathogenic Leptospira in Ireland.

    PubMed

    Nally, Jarlath E; Arent, Zbigniew; Bayles, Darrell O; Hornsby, Richard L; Gilmore, Colm; Regan, Siobhan; McDevitt, Allan D; Yearsley, Jon; Fanning, Séamus; McMahon, Barry J

    2016-12-01

    The greater white-toothed shrew (Crocidura russula) is an invasive mammalian species that was first recorded in Ireland in 2007. It currently occupies an area of approximately 7,600 km2 on the island. C. russula is normally distributed in Northern Africa and Western Europe, and was previously absent from the British Isles. Whilst invasive species can have dramatic and rapid impacts on faunal and floral communities, they may also be carriers of pathogens facilitating disease transmission in potentially naive populations. Pathogenic leptospires are endemic in Ireland and a significant cause of human and animal disease. From 18 trapped C. russula, 3 isolates of Leptospira were cultured. However, typing of these isolates by standard serological reference methods was negative, and suggested an, as yet, unidentified serovar. Sequence analysis of 16S ribosomal RNA and secY indicated that these novel isolates belong to Leptospira alstonii, a unique pathogenic species of which only 7 isolates have been described to date. Earlier isolations were limited geographically to China, Japan and Malaysia, and this leptospiral species had not previously been cultured from mammals. Restriction enzyme analysis (REA) further confirms the novelty of these strains since no similar patterns were observed with a reference database of leptospires. As with other pathogenic Leptospira species, these isolates contain lipL32 and do not grow in the presence of 8-azagunaine; however no evidence of disease was apparent after experimental infection of hamsters. These isolates are genetically related to L. alstonii but have a novel REA pattern; they represent a new serovar which we designate as serovar Room22. This study demonstrates that invasive mammalian species act as bridge vectors of novel zoonotic pathogens such as Leptospira.

  11. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. To improve the control of this disease it’s necessary to better understand the pathog...

  12. Rapid cell-based assay for detection and quantification of active staphylococcal enterotoxin type D

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Food poisoning by Staphylococcus aureus is a result of ingestion of Staphylococcal enterotoxins (SEs) produced by this bacterium and is a major source of foodborne illness. Staphylococcal enterotoxin D (SED) is one of the predominant enterotoxins recovered in Staphylococcal food poisoning incidences...

  13. Side effects of rodent control on non-target species: Rodenticides increase parasite and pathogen burden in great bustards.

    PubMed

    Lemus, J A; Bravo, C; García-Montijano, M; Palacín, C; Ponce, C; Magaña, M; Alonso, J C

    2011-10-15

    For many years anticoagulant rodenticides have been used in vole control campaigns, in spite of the proven risk of secondary poisoning of non-target predators and scavengers. In this paper we analyse for the first time great bustard exposure and intoxication by anticoagulant rodenticides in Spain, based on residues found in the livers of 71 bustard carcasses collected during 1991-2010. Ten individuals contained chlorophacinone and one flocoumafen. Chlorophacinone level was significantly correlated with the pathogen and parasite burden of intoxicated birds. Moreover, through the last 12 years the annual number of great bustards that present chlorophacinone in liver collected in our study areas was correlated with vole peaks at a nearby area, suggesting that the ingestion of rodenticide was proportional to the amounts spread in the fields. We conclude that rodenticide consumption is a regular event among great bustards when baited cereal is spread on fields, and that this may cause chronic weakening of intoxicated individuals, possibly affecting their survival. Future rodent control actions should consider these negative side effects on non target granivorous steppe and farmland species, particularly when they are globally threatened.

  14. Reactive oxygen species-dependent necroptosis in Jurkat T cells induced by pathogenic free-living Naegleria fowleri.

    PubMed

    Song, K-J; Jang, Y S; Lee, Y A; Kim, K A; Lee, S K; Shin, M H

    2011-07-01

    Naegleria fowleri, a free-living amoeba, is the causative pathogen of primary amoebic meningoencephalitis in humans and experimental mice. N. fowleri is capable of destroying tissues and host cells through lytic necrosis. However, the mechanism by which N. fowleri induces host cell death is unknown. Electron microscopy indicated that incubation of Jurkat T cells with N. fowleri trophozoites induced necrotic morphology of the Jurkat T cells. N. fowleri also induced cytoskeletal protein cleavage, extensive poly (ADP-ribose) polymerase hydrolysis and lactate dehydrogenase (LDH) release. Although no activation of caspase-3 was observed in Jurkat T cells co-incubated with amoebae, intracellular reactive oxygen species (ROS) were strongly generated by NADPH oxidase (NOX). Pretreating cells with necroptosis inhibitor necrostatin-1 or NOX inhibitor diphenyleneiodonium chloride (DPI) strongly inhibited amoeba-induced ROS generation and Jurkat cell death, whereas pan-caspase inhibitor z-VAD-fmk did not. N. fowleri-derived secretory products (NfSP) strongly induced intracellular ROS generation and cell death. Necroptotic effects of NfSP were effectively inhibited by pretreating NfSP with proteinase K. Moreover, NfSP-induced LDH release and intracellular ROS accumulation were inhibited by pretreating Jurkat T cells with DPI or necrostatin-1. These results suggest that N. fowleri induces ROS-dependent necroptosis in Jurkat T cells.

  15. Crystal structure of the superantigen staphylococcal enterotoxin type A.

    PubMed Central

    Schad, E M; Zaitseva, I; Zaitsev, V N; Dohlsten, M; Kalland, T; Schlievert, P M; Ohlendorf, D H; Svensson, L A

    1995-01-01

    Staphylococcal enterotoxins are prototype superantigens characterized by their ability to bind to major histocompatibility complex (MHC) class II molecules and subsequently activate a large fraction of T-lymphocytes. The crystal structure of staphylococcal enterotoxin type A (SEA), a 27 kDa monomeric protein, was determined to 1.9 A resolution with an R-factor of 19.9% by multiple isomorphous replacement. SEA is a two domain protein composed of a beta-barrel and a beta-grasp motif demonstrating the same general structure as staphylococcal enterotoxins SEB and TSST-1. Unique for SEA, however, is a Zn2+ coordination site involved in MHC class II binding. Four amino acids including Ser1, His187, His225 and Asp227 were found to be involved in direct coordination of the metal ion. SEA is the first Zn2+ binding enterotoxin that has been structurally determined. Images PMID:7628431

  16. Characterization of novel type C staphylococcal enterotoxins: biological and evolutionary implications.

    PubMed Central

    Marr, J C; Lyon, J D; Roberson, J R; Lupher, M; Davis, W C; Bohach, G A

    1993-01-01

    The type C staphylococcal enterotoxins (SEC) are a group of highly conserved proteins with significant immunological cross-reactivity. Although three antigenically distinct SEC subtypes (SEC1, SEC2, and SEC3) have been reported in the literature, we observed that the isoelectric points of SEC from several Staphylococcus aureus isolates are different from those of any of these three subtypes. This observation led us to propose that additional SEC molecular variants exist. For assessment of this possibility, the sec genes from representative human, animal, and food isolates were cloned and sequenced. The toxins encoded by the 18 isolates used in this study included five unique SEC proteins in addition to SEC1, SEC2, and SEC3. Six of the SEC proteins (including SEC1, SEC2, and SEC3) were produced by human and food isolates. Analysis of seven bovine and ovine isolates showed that isolates from each animal species produced a unique host-specific SEC. All of the SEC caused lymphocyte proliferation, although some of the toxins differed in their ability to stimulate cells from several animal species. An explanation for these results, which is supported by our phenotypic analysis of Sec+ staphylococcal isolates, is that toxin heterogeneity is due to selection for modified SEC sequences that facilitate the survival of S. aureus isolates in their respective hosts. Images PMID:8406814

  17. Regulatory organization of the staphylococcal sae locus.

    PubMed

    Adhikari, Rajan P; Novick, Richard P

    2008-03-01

    This paper describes an investigation of the complex internal regulatory circuitry of the staphylococcal sae locus and the impact of modifying this circuitry on the expression of external genes in the sae regulon. The sae locus contains four genes, the saeR and S two-component signalling module (TCS), and saeP and Q, two upstream genes of hitherto unknown function. It is expressed from two promoters, P(A)sae, which transcribes only the TCS, and P(C)sae, which transcribes the entire locus. A bursa aurealis (bursa) transposon insertion in saeP in a derivative of Staphylococcus aureus NCTC 8325 has a profound effect on sae function. It modifies the activity of the TCS, changing the expression of many genes in the sae regulon, even though transcription of the TCS (from P(A)sae) is not interrupted. Moreover, these effects are not due to disruption of saeP since an in-frame deletion in saeP has essentially no phenotype. The phenotype of S. aureus strain Newman is remarkably similar to that of the saeP : : bursa and this similarity is explained by an amino acid substitution in the Newman saeS gene that is predicted to modify profoundly the signalling function of the protein. This concurrence suggests that the saeP : : bursa insertion affects the signalling function of saeS, a suggestion that is supported by the ability of an saeQR clone, but not an saeR clone, to complement the effects of the saeP : : bursa insertion.

  18. The Pseudomonas viridiflava phylogroups in the P. syringae species complex are characterized by genetic variability and phenotypic plasticity of pathogenicity-related traits.

    PubMed

    Bartoli, Claudia; Berge, Odile; Monteil, Caroline L; Guilbaud, Caroline; Balestra, Giorgio M; Varvaro, Leonardo; Jones, Corbin; Dangl, Jeffery L; Baltrus, David A; Sands, David C; Morris, Cindy E

    2014-07-01

    As a species complex, Pseudomonas syringae exists in both agriculture and natural aquatic habitats. P.viridiflava, a member of this complex, has been reported to be phenotypically largely homogenous. We characterized strains from different habitats, selected based on their genetic similarity to previously described P.viridiflava strains. We revealed two distinct phylogroups and two different kinds of variability in phenotypic traits and genomic content. The strains exhibited phase variation in phenotypes including pathogenicity and soft rot on potato. We showed that the presence of two configurations of the Type III Secretion System [single (S-PAI) and tripartite (T-PAI) pathogenicity islands] are not correlated with pathogenicity or with the capacity to induce soft rot in contrast to previous reports. The presence/absence of the avrE effector gene was the only trait we found to be correlated with pathogenicity of P.viridiflava. Other Type III secretion effector genes were not correlated with pathogenicity. A genomic region resembling an exchangeable effector locus (EEL) was found in S-PAI strains, and a probable recombination between the two PAIs is described. The ensemble of the variability observed in these phylogroups of P.syringae likely contributes to their adaptability to alternating opportunities for pathogenicity or saprophytic survival.

  19. Quaternized cashew gum: An anti-staphylococcal and biocompatible cationic polymer for biotechnological applications.

    PubMed

    Quelemes, Patrick V; de Araújo, Alyne R; Plácido, Alexandra; Delerue-Matos, Cristina; Maciel, Jeanny S; Bessa, Lucinda J; Ombredane, Alicia S; Joanitti, Graziella A; Soares, Maria José Dos S; Eaton, Peter; da Silva, Durcilene A; Leite, José Roberto S A

    2017-02-10

    Chemical modifications to cashew gum (CG) structure have been previously reported to obtain new physicochemical characteristics, however until now there were no reports of modifications by introduction of new functional groups to add cationic character. This study presents a quaternization route for CG using a quaternary ammonium reagent. The chemical features of the quaternized cashew gum derivatives (QCG) were analyzed by: FTIR, elemental analysis, degree of substitution, Zeta potential, (1)H NMR and (1)H-(13)C correlation (HSQC). QCG were evaluated for their anti-staphylococcal activity by determining minimum inhibitory and bactericidal concentrations against pathogenic Staphylococcus spp. and by imaging using atomic force microscopy. Moreover, the mammalian cell biocompatibility were also assessed through hemolytic and cell toxicity assays. QCG presented promising antimicrobial activity against methicillin-resistant S. aureus and biocompatibility on tested cells. These results show that QCG could be a promising tool in the development of biomaterials with an anti-septic action.

  20. Staphylococcal enterotoxin B-specific electrochemiluminescence and lateral flow device assays cross-react with staphylococcal enterotoxin D.

    PubMed

    Tallent, Sandra M; Hait, Jennifer; Bennett, Reginald W

    2014-01-01

    Guam school children and faculty members experienced symptoms of vomiting, nausea, abdominal cramps, and diarrhea shortly after eating breakfast prepared by contracted caterers. The first illness was reported within an hour after breakfast, affecting 295 students and two faculty members. Local hospitals treated 130 people, and 61 were admitted for further treatment. Reported symptoms were consistent with staphylococcal food poisoning. Initial food testing using a lateral flow device and electrochemiluminescence method incorrectly implicated staphylococcal enterotoxin B as the causative agent, prompting partial activation of Guam's Emergency Response Center. Traditional ELISAs proved that the food poisoning agent was staphylococcal enterotoxin D. More specific and sensitive assays would have alleviated the issues and confusion that surrounded the reporting and investigation of this outbreak.

  1. Multilocus genetic characterization of two ant vectors (Group II "Dirty 22" species) known to contaminate food and food products and spread foodborne pathogens.

    PubMed

    Sulaiman, Irshad M; Anderson, Mickey; Oi, David H; Simpson, Steven; Kerdahi, Khalil

    2012-08-01

    The U.S. Food and Drug Administration utilizes the presence of filth and extraneous materials as one of the criteria for implementing regulatory actions and assessing adulteration of food products of public health importance. Twenty-two prevalent pest species (also known as the ''Dirty 22'' species) have been considered by this agency as possible vehicles for the spread of foodborne diseases, and the presence of these species is considered an indicator of unsanitary conditions in food processing and storage facilities. In a previous study, we further categorized the Dirty 22 species into four groups: group I includes four cockroach species, group II includes two ant species, group III includes 12 fly species, and group IV includes four rodent species. Here, we describe the development of three nested PCR primer sets and multilocus genetic characterization by amplifying the small subunit rRNA, elongation factor 1-alpha, and wingless (WNT-1) genes of group II Dirty 22 ant species Monomorium pharaonis and Solenopsis molesta. These novel group II Dirty 22 species-specific nested PCR primer sets can be used when the specimens cannot be identified using conventional microscopic methods. These newly developed assays will provide correct identification of group II Dirty 22 ant species, and the information can be used in the control of foodborne pathogens.

  2. Rapid Quantitative Serological Assay of Staphylococcal Enterotoxin B

    PubMed Central

    Weirether, Francis J.; Lewis, Evelyn E.; Rosenwald, Albert J.; Lincoln, Ralph E.

    1966-01-01

    A simple, rapid method, based on the Oudin single diffusion technique, is described for the quantitative assay of staphylococcal enterotoxin B. The method yields reproducible results without close control of such assay variables as temperature, antiserum dilution, and assay time, provided that the ionic strength is maintained above 0.2 n sodium chloride equivalent. PMID:4959985

  3. Evolution of N-species Kimura/voter models towards criticality, a surrogate for general models of accidental pathogens

    NASA Astrophysics Data System (ADS)

    Ghaffari, Peyman; Stollenwerk, Nico

    2012-09-01

    In models for accidental pathogens, with the paradigmatic epidemiological system of bacterial meningitis, there was evolution towards states exhibiting critical fluctuations with power law behaviour observed [1]. This is a model with many possibly pathogenic strains essentially evolving independently to low pathogenicity. A first and previous study had shown that in the limit of vanishing pathogenicity there are critical fluctuations with power law distributions observed, already when only two strains interact [2]. This earlier version of a two strain model was very recently reinvestigated [3] and named as Stollenwerk-Jansen model (SJ). Muñoz et al. demonstrated that this two-strain model for accidental pathogens is in the universality class of the so-called voter model. Though this model clearly shows criticality, its control parameter, the pathogenicity, is not self-tuning towards criticality. However, the multi-strain version mentioned above [1] is well evolving towards criticality, as well as a spatially explicit version of this, shown in [4] p. 155. These models of multi-strain type including explicitly mutations of the pathogenicity can be called SJ-models of type II [5]. Since the original epidemiological model is of SIRYX-type, the evolution to zero pathogenicity is slow and perturbed by large population noise. In the present article we now show on the basis of the notion of the voter-model universality classes the evolution of n-voter models with mutaion towards criticality, now much less perturbed by population noise, hence demonstrating a clear mechanism of self-organized criticality in the sense of [6, 7]. The present results have wide implications for many diseases in which a large proportion of infections is asymptomatic, meaning that the system has already evolved towards an average low pathogenicity. This holds not only for the original paradigmatic case of bacterial meningitis, but was reecently also suggested for example for dengue fever (DENFREE

  4. Tandem repeat sequence analysis of staphylococcal protein A (spa) gene in methicillin-resistant Staphylococcus pseudintermedius.

    PubMed

    Moodley, Arshnee; Stegger, Marc; Ben Zakour, Nouri L; Fitzgerald, J Ross; Guardabassi, Luca

    2009-03-30

    A putative staphylococcal protein A (spa) gene was discovered in the genome of Staphylococcus pseudintermedius and used for developing a species-specific spa typing protocol. Thirty-one clinical methicillin-resistant S. pseudintermedius (MRSP) isolates from dogs and cats in four countries were characterized by spa typing, pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome (SCCmec) typing. The results indicated the occurrence of two MRSP clones that acquired distinct SCCmec elements in Europe (t02, PFGE type A, SCCmec type III,) and California (t06, PFGE type B, SCCmec type V). Sequence analysis of mecA revealed the occurrence of four alleles (mecA1 to mecA4), which correlated with the geographical origin of the isolates and enabled discrimination of two distinct subtypes within the European clone. The newly developed spa typing method appeared to be a promising tool for easy and rapid typing of MRSP, either alone or in combination with SCCmec and mecA typing for fine-structure epidemiological analysis.

  5. Rapid identification of pathogenic species of Neisseria by carbohydrate degradation tests. Importance of glucose in media used for preparation of inocula.

    PubMed Central

    Tapsall, J W; Cheng, J K

    1981-01-01

    Pathogenic species of Neisseria were identified more readily by carbohydrate degradation tests when 0.5% glucose was used in media from which inocula for the test were obtained. This improved the performance of both non-growth and growth-dependent methods for these tests. One of the three techniques used a non-nutrient buffered salt solution and depended on the presence of preformed enzymes. This test was more accurate and rapid than the two growth-dependent techniques. PMID:7023603

  6. Coverage of related pathogenic species by multivalent and cross-protective vaccine design: arenaviruses as a model system.

    PubMed

    Botten, Jason; Sidney, John; Mothé, Bianca R; Peters, Bjoern; Sette, Alessandro; Kotturi, Maya F

    2010-06-01

    The arenaviruses are a family of negative-sense RNA viruses that cause severe human disease ranging from aseptic meningitis to hemorrhagic fever syndromes. There are currently no FDA-approved vaccines for the prevention of arenavirus disease, and therapeutic treatment is limited to the use of ribavirin and/or immune plasma for a subset of the pathogenic arenaviruses. The considerable genetic variability observed among the seven arenaviruses that are pathogenic for humans illustrates one of the major challenges for vaccine development today, namely, to overcome pathogen heterogeneity. Over the past 5 years, our group has tested several strategies to overcome pathogen heterogeneity, utilizing the pathogenic arenaviruses as a model system. Because T cells play a prominent role in protective immunity following arenavirus infection, we specifically focused on the development of human vaccines that would induce multivalent and cross-protective cell-mediated immune responses. To facilitate our vaccine development and testing, we conducted large-scale major histocompatibility complex (MHC) class I and class II epitope discovery on murine, nonhuman primate, and human backgrounds for each of the pathogenic arenaviruses, including the identification of protective HLA-restricted epitopes. Finally, using the murine model of lymphocytic choriomeningitis virus infection, we studied the phenotypic characteristics associated with immunodominant and protective T cell epitopes. This review summarizes the findings from our studies and discusses their application to future vaccine design.

  7. Fragments of β-thymosin from the sea urchin Paracentrotus lividus as potential antimicrobial peptides against staphylococcal biofilms.

    PubMed

    Schillaci, Domenico; Vitale, Maria; Cusimano, Maria Grazia; Arizza, Vincenzo

    2012-10-01

    The immune mediators in echinoderms can be a potential source of novel antimicrobial peptides (AMPs) applied toward controlling pathogenic staphylococcal biofilms that are intrinsically resistant to conventional antibiotics. The peptide fraction <5 kDa from the cytosol of coelomocytes of the sea urchin Paracentrotus lividus (5-CC) was tested against a group of Gram-positive and Gram-negative pathogen reference strains. The 5-CC of P. lividus was active against all planktonic-tested strains but also showed antibiofilm properties against staphylococcal strains. Additionally, we demonstrated the presence of three small peptides in the 5-CC belonging to segment 9-41 of a P. lividusβ-thymosin. The smallest of these peptides in particular, showed the common chemical-physical characteristics of AMPs. This novel AMP from β-thymosin has high potential activity as an antibiofilm agent, acting on slow-growing bacterial cells that exhibit a reduced susceptibility to conventional antibiotics and represent a reservoir for recurrent biofilm-associated infections.

  8. Genome analysis of the staphylococcal temperate phage DW2 and functional studies on the endolysin and tail hydrolase

    PubMed Central

    Keary, Ruth; McAuliffe, Olivia; Ross, R Paul; Hill, Colin; O’Mahony, Jim; Coffey, Aidan

    2014-01-01

    This study describes the genome of temperate Siphoviridae phage DW2, which is routinely propagated on Staphylococcus aureus DPC5246. The 41941 bp genome revealed an open reading frame (ORF1) which has a high level of homology with members of the resolvase subfamily of site-specific serine recombinase, involved in chromosomal integration and excision. In contrast, the majority of staphylococcal phages reported to date encode tyrosine recombinases. Two putative genes encoded by phage DW2 (ORF15 and ORF24) were highly homologous to the NWMN0273 and NWMN0280 genes encoding virulence factors carried on the genome of ϕNM4, a prophage in the genome of S. aureus Newman. Phage DW2 also encodes proteins highly homologous to two well-characterized Staphylococcus aureus pathogenicity island derepressors encoded by the staphylococcal helper phage 80α indicating that it may similarly act as a helper phage for mobility of pathogenicity islands in S. aureus. This study also focused on the enzybiotic potential of phage DW2. The structure of the putative endolysin and tail hydrolase were investigated and used as the basis for a cloning strategy to create recombinant peptidoglycan hydrolyzing proteins. After overexpression in E. coli, four of these proteins (LysDW2, THDW2, CHAPE1-153, and CHAPE1-163) were demonstrated to have hydrolytic activity against peptidoglycan of S. aureus and thus represent novel candidates for exploitation as enzybiotics. PMID:25105056

  9. Identification of a novel pathogenic Borrelia species causing Lyme borreliosis with unusually high spirochaetaemia: a descriptive study

    PubMed Central

    Pritt, Bobbi S; Mead, Paul S; Hoang Johnson, Diep K; Neitzel, David F; Respicio-Kingry, Laurel B; Davis, Jeffrey P; Schiffman, Elizabeth; Sloan, Lynne M; Schriefer, Martin E; Replogle, Adam J; Paskewitz, Susan M; Ray, Julie A; Bjork, Jenna; Steward, Christopher R; Deedon, Alecia; Lee, Xia; Kingry, Luke C; Miller, Tracy K; Feist, Michelle A; Theel, Elitza S; Patel, Robin; Irish, Cole L; Petersen, Jeannine M

    2016-01-01

    Summary Background Lyme borreliosis is the most common tick-borne disease in the northern hemisphere. It is a multisystem disease caused by Borrelia burgdorferi sensu lato genospecies and characterised by tissue localisation and low spirochaetaemia. In this study we aimed to describe a novel Borrelia species causing Lyme borreliosis in the USA. Methods At the Mayo clinic, from 2003 to 2014, we tested routine clinical diagnostic specimens from patients in the USA with PCR targeting the oppA1 gene of B burgdorferi sensu lato. We identified positive specimens with an atypical PCR result (melting temperature outside of the expected range) by sequencing, microscopy, or culture. We collected Ixodes scapularis ticks from regions of suspected patient tick exposure and tested them by oppA1 PCR. Findings 100 545 specimens were submitted by physicians for routine PCR from Jan 1, 2003 to Sept 30, 2014. From these samples, six clinical specimens (five blood, one synovial fluid) yielded an atypical oppA1 PCR product, but no atypical results were detected before 2012. Five of the six patients with atypical PCR results had presented with fever, four had diffuse or focal rash, three had symptoms suggestive of neurological inclusion, and two were admitted to hospital. The sixth patient presented with knee pain and swelling. Motile spirochaetes were seen in blood samples from one patient and cultured from blood samples from two patients. Among the five blood specimens, the median oppA1 copy number was 180 times higher than that in 13 specimens that tested positive for B burgdorferi sensu stricto during the same time period. Multigene sequencing identified the spirochaete as a novel B burgdorferi sensu lato genospecies. This same genospecies was detected in ticks collected at a probable patient exposure site. Interpretation We describe a new pathogenic Borrelia burgdorferi sensu lato genospecies (candidatus Borrelia mayonii) in the upper midwestern USA, which causes Lyme borreliosis

  10. Identification of Babesia species infecting dogs using reverse line blot hybridization for six canine piroplasms, and evaluation of co-infection by other vector-borne pathogens.

    PubMed

    Yisaschar-Mekuzas, Yael; Jaffe, Charles L; Pastor, Josep; Cardoso, Luís; Baneth, Gad

    2013-01-31

    Canine infection by vector-borne hemoparasites is frequent in tropical and sub-tropical areas where exposure to hematophageous ectoparasites is intensive. A reverse line blot (RLB) assay was designed to improve the simultaneous detection of all named canine piroplasm species combined with other vector-borne pathogens of dogs including Ehrlichia canis, Hepatozoon canis and Leishmania infantum common in the Mediterranean basin. Blood samples of 110 dogs from Spain (n=21), Portugal (n=14) and Israel (n=75) were analyzed. The study evaluated 2 groups of dogs, 49 dogs with piroplasm infection detected by blood smear microscopy from Portugal, Spain and Israel, and 61 dogs surveyed from rural areas in Israel, for which infection status with vector-borne pathogens was unknown. Among the dogs previously diagnosed with piroplasmosis, infection with Babesia canis, Babesia vogeli, Babesia gibsoni and Theileria annae was detected in the Iberian dogs while only B. vogeli was found in Israeli dogs. These differences are attributed to the absence of tick vectors for some piroplasm species such as Dermacentor reticulatus in Israel. Eleven (79%) of the Babesia-positive dogs from Portugal were co-infected with other pathogens including L. infantum, H. canis and E. canis. Eight of 61 (13%) rural Israeli dogs were co-infected with two or more pathogens including B. vogeli, L. infantum, E. canis, and H. canis. Triple infections were demonstrated in 2 dogs. The RLB detection limit for Babesia was 50-fold lower than that of PCR. This study presents a RLB to simultaneously detect and separate the major vector-borne dog pathogens in southern Europe and the Middle East.

  11. Antifungal Activity of a Synthetic Cationic Peptide against the Plant Pathogens Colletotrichum graminicola and Three Fusarium Species.

    PubMed

    Johnson, Eric T; Evans, Kervin O; Dowd, Patrick F

    2015-09-01

    A small cationic peptide (JH8944) was tested for activity against a number of pathogens of agricultural crops. JH8944 inhibited conidium growth in most of the tested plant pathogens with a dose of 50 μg/ml, although one isolate of Fusarium oxysporum was inhibited at 5 μg/ml of JH8944. Most conidia of Fusarium graminearum were killed within 6 hours of treatment with 50 μg/ml of JH8944. Germinating F. graminearum conidia required 238 μg/ml of JH8944 for 90% growth inhibition. The peptide did not cause any damage to tissues surrounding maize leaf punctures when tested at a higher concentration of 250 μg/ml even after 3 days. Liposomes consisting of phosphatidylglycerol were susceptible to leakage after treatment with 25 and 50 μg/ml of JH8944. These experiments suggest this peptide destroys fungal membrane integrity and could be utilized for control of crop fungal pathogens.

  12. Role of hospital surfaces in the transmission of emerging health care-associated pathogens: norovirus, Clostridium difficile, and Acinetobacter species.

    PubMed

    Weber, David J; Rutala, William A; Miller, Melissa B; Huslage, Kirk; Sickbert-Bennett, Emily

    2010-06-01

    Health care-associated infections (HAI) remain a major cause of patient morbidity and mortality. Although the main source of nosocomial pathogens is likely the patient's endogenous flora, an estimated 20% to 40% of HAI have been attributed to cross infection via the hands of health care personnel, who have become contaminated from direct contact with the patient or indirectly by touching contaminated environmental surfaces. Multiple studies strongly suggest that environmental contamination plays an important role in the transmission of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus spp. More recently, evidence suggests that environmental contamination also plays a role in the nosocomial transmission of norovirus, Clostridium difficile, and Acinetobacter spp. All 3 pathogens survive for prolonged periods of time in the environment, and infections have been associated with frequent surface contamination in hospital rooms and health care worker hands. In some cases, the extent of patient-to-patient transmission has been found to be directly proportional to the level of environmental contamination. Improved cleaning/disinfection of environmental surfaces and hand hygiene have been shown to reduce the spread of all of these pathogens. Importantly, norovirus and C difficile are relatively resistant to the most common surface disinfectants and waterless alcohol-based antiseptics. Current hand hygiene guidelines and recommendations for surface cleaning/disinfection should be followed in managing outbreaks because of these emerging pathogens.

  13. Rapid qualitative method for detecting staphylococcal nuclease in foods.

    PubMed Central

    Koupal, A; Deibel, R H

    1978-01-01

    A rapid method for the detection of heat-stable staphylococcal nuclease in foods is described. The procedure consists of an acid precipitation, boiling, and centrifugation followed by enzyme detection in an agar plate containing deoxyribonucleic acid. To test the efficacy of the procedure, purified Staphylococcus aureus nuclease was added to various foods and recovery experiments were performed. Additionally, foods were inoculated and incubated with S. aureus, and the staphylococcal counts were compared with nuclease activity. The results indicate that the procedure possesses merit for a rapid method that can be incorporated into quality control programs. The procedure requires approximately 2.5 h, and it will detect nuclease levels as low as 10 ng/g of food. Images PMID:677882

  14. Weak effect of metal type and ica genes on staphylococcal infection of titanium and stainless steel implants.

    PubMed

    Hudetz, D; Ursic Hudetz, S; Harris, L G; Luginbühl, R; Friederich, N F; Landmann, R

    2008-12-01

    Currently, ica is considered to be the major operon responsible for staphylococcal biofilm. The effect of biofilm on susceptibility to staphylococcal infection of different implant materials in vivo is unclear. The interaction of ica-positive (wild-type (WT)) and ica-negative (ica(-)) Staphylococcus aureus and Staphylococcus epidermidis strains with titanium and both smooth and rough stainless steel surfaces was studied by scanning electron microscopy in vitro and in a mouse tissue cage model during 2 weeks following perioperative or postoperative inoculation in vivo. In vitro, WT S. epidermidis adhered equally and more strongly than did WT S. aureus to all materials. Both WT strains, but not ica(-) strains, showed multilayered biofilm. In vivo, 300 CFUs of WT and ica(-)S. aureus led, in all metal cages, to an infection with a high level of planktonic CFUs and only 0.89% adherent CFUs after 8 days. In contrast, 10(6) CFUs of the WT and ica(-) strains were required for postoperative infection with S. epidermidis. In all metal types, planktonic numbers of S. epidermidis dropped to <100 WT, and adherent CFUs were low in WT-infected cages and absent in ica(-)-infected cages after 14 days. Perioperative S. epidermidis inoculation resulted in slower clearance than postoperative inoculation, and in titanium cages adherent WT bacteria survived in higher numbers than ica(-) bacteria. In conclusion, the metal played a minor role in susceptibility to and persistence of staphylococcal infection; the presence of ica genes had a strong effect on biofilm in vitro and a weak effect in vivo; and S. epidermidis was more pathogenic when introduced during implantation than after implantation.

  15. Staphylococcal Adhesion, Detachment and Transmission on Nanopillared Si Surfaces.

    PubMed

    Hizal, Ferdi; Choi, Chang-Hwan; Busscher, Henk J; van der Mei, Henny C

    2016-11-09

    Nanostructured surfaces are extensively considered with respect to their potential impact on bacterial adhesion from aqueous suspensions or air, but in real-life bacteria are often transmitted between surfaces. Mechanistically, transmission involves detachment of adhering bacteria from a donor and adhesion to a receiver surface, controlled by the relative values of the adhesion forces exerted by both surfaces. We here relate staphylococcal adhesion, detachment and transmission to, from, and between smooth and nanopillared-Si surfaces with staphylococcal adhesion forces. Nanopillared-Si surfaces were prepared with pillar-to-pillar distances of 200, 400, and 800 nm. On smooth surfaces, staphylococcal adhesion forces, measured using bacterial-probe Atomic-Force-Microscopy, amounted to 4.4-6.8 and 1.8-2.1 nN (depending on the AFM-loading force) for extracellular-polymeric-substances (EPS) producing and non-EPS producing strains, respectively. Accordingly the EPS producing strain adhered in higher numbers than the non-EPS producing strain. Fractional adhesion forces on nanopillared-Si surfaces relative to the smooth surface ranged from 0.30 to 0.95, depending on AFM-loading force, strain and pillar-to-pillar distance. However, for each strain, the number of adhering bacteria remained similar on all nanopillared surfaces. Detachment of adhering staphylococci decreased significantly with increasing adhesion forces, while staphylococcal transmission to a receiver surface also decreased with increasing adhesion force exerted by the donor. In addition, the strain with ability to produce EPS was killed in high percentages and induced to produce EPS during transmission on nanopillared-Si surfaces, presumably by high local cell-wall stresses. This must be accounted for in applications of nanostructured surfaces: whereas killing may be favorable, EPS production may reduce antimicrobial efficacy.

  16. Monkey Feeding Assay for Testing Emetic Activity of Staphylococcal Enterotoxin.

    PubMed

    Seo, Keun Seok

    2016-01-01

    Staphylococcal enterotoxins (SEs) are unique bacterial toxins that cause gastrointestinal toxicity as well as superantigenic activity. Since systemic administration of SEs induces superantigenic activity leading to toxic shock syndrome that may mimic enterotoxic activity of SEs such as vomiting and diarrhea, oral administration of SEs in the monkey feeding assay is considered as a standard method to evaluate emetic activity of SEs. This chapter summarizes and discusses practical considerations of the monkey feeding assay used in studies characterizing classical and newly identified SEs.

  17. Expression of staphylococcal enterotoxin C1 in Escherichia coli.

    PubMed Central

    Bohach, G A; Schlievert, P M

    1987-01-01

    The structural gene encoding staphylococcal enterotoxin C1 was cloned into Escherichia coli and localized on a 1.5-kilobase HindIII-ClaI DNA fragment by subcloning. The toxin was partially purified from E. coli clones and shown to be immunologically identical to enterotoxin C1 from Staphylococcus aureus. The cloned toxin also had the same molecular weight (26,000) and charge heterogeneity as staphylococcus-derived enterotoxin. Toxins from both sources were equally biologically active. Images PMID:3542834

  18. Therapeutic Human Hyperimmune Polyclonal Antibodies Against Staphylococcal Enterotoxin B

    DTIC Science & Technology

    2008-05-01

    AD_________________ Award Number: W81XWH-08-C-0004 TITLE: Therapeutic Human Hyperimmune Polyclonal Antibodies against Staphylococcal...01-05-2008 2. REPORT TYPE Final, Phase I 3. DATES COVERED 19 OCT 2007 - 18 APR 2008 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Therapeutic ...aerosol in a biowarfare scenario. The primary goal of Phase I was to demonstrate the feasibility of therapeutic intervention with immunoglobulin

  19. Repurposing ebselen for treatment of multidrug-resistant staphylococcal infections

    PubMed Central

    Thangamani, Shankar; Younis, Waleed; Seleem, Mohamed N.

    2015-01-01

    Novel antimicrobials and new approaches to developing them are urgently needed. Repurposing already-approved drugs with well-characterized toxicology and pharmacology is a novel way to reduce the time, cost, and risk associated with antibiotic innovation. Ebselen, an organoselenium compound, is known to be clinically safe and has a well-known pharmacology profile. It has shown potent bactericidal activity against multidrug-resistant clinical isolates of staphylococcus aureus, including methicillin- and vancomycin-resistant S. aureus (MRSA and VRSA). We demonstrated that ebselen acts through inhibition of protein synthesis and subsequently inhibited toxin production in MRSA. Additionally, ebselen was remarkably active and significantly reduced established staphylococcal biofilms. The therapeutic efficacy of ebselen was evaluated in a mouse model of staphylococcal skin infections. Ebselen 1% and 2% significantly reduced the bacterial load and the levels of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and monocyte chemo attractant protein-1 (MCP-1) in MRSA USA300 skin lesions. Furthermore, it acts synergistically with traditional antimicrobials. This study provides evidence that ebselen has great potential for topical treatment of MRSA skin infections and lays the foundation for further analysis and development of ebselen as a potential treatment for multidrug-resistant staphylococcal infections. PMID:26111644

  20. Detection of staphylococcal exfoliative toxin by slide latex agglutination.

    PubMed Central

    Murono, K; Fujita, K; Yoshioka, H

    1988-01-01

    A simple and rapid method in which slide latex agglutination was used was developed to detect the exfoliative toxin (ET) elaborated by clinical isolates. ET types A and B (ET-A and ET-B) were purified by plate gel isoelectrofocusing, and anti-ET sera were obtained by immunizing rabbits. A specific immunoglobulin G antitoxin was then prepared from the immunized rabbit sera by fast protein liquid chromatography, and latex particles were coated with the antitoxin. Of 74 staphylococcal strains isolated from patients with staphylococcal scalded skin syndrome, 61 strains were found to produce ET by the newborn mouse bioassay. All 61 strains were shown to be positive for ET-A and ET-B production by the slide latex agglutination method. The lowest concentration of ETs detected by the latex agglutination method was 0.5 microgram/ml, which was much lower than that detected by the double immunodiffusion method, with a sensitivity of 50 micrograms/ml. It is crucial to prove ET production by clinical isolates for the diagnosis and surveillance of staphylococcal scalded skin syndrome. The latex agglutination method is a sensitive, simple, and rapid test which can be used as an alternative to the newborn mouse bioassay. Images PMID:3343322

  1. Staphylococcal Enterotoxin P Predicts Bacteremia in Hospitalized Patients Colonized With Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Calderwood, Michael S.; Desjardins, Christopher A.; Sakoulas, George; Nicol, Robert; DuBois, Andrea; Delaney, Mary L.; Kleinman, Ken; Cosimi, Lisa A.; Feldgarden, Michael; Onderdonk, Andrew B.; Birren, Bruce W.; Platt, Richard; Huang, Susan S.

    2014-01-01

    Background. Methicillin-resistant Staphylococcus aureus (MRSA) colonization predicts later infection, with both host and pathogen determinants of invasive disease. Methods. This nested case-control study evaluates predictors of MRSA bacteremia in an 8–intensive care unit (ICU) prospective adult cohort from 1 September 2003 through 30 April 2005 with active MRSA surveillance and collection of ICU, post-ICU, and readmission MRSA isolates. We selected MRSA carriers who did (cases) and those who did not (controls) develop MRSA bacteremia. Generating assembled genome sequences, we evaluated 30 MRSA genes potentially associated with virulence and invasion. Using multivariable Cox proportional hazards regression, we assessed the association of these genes with MRSA bacteremia, controlling for host risk factors. Results. We collected 1578 MRSA isolates from 520 patients. We analyzed host and pathogen factors for 33 cases and 121 controls. Predictors of MRSA bacteremia included a diagnosis of cancer, presence of a central venous catheter, hyperglycemia (glucose level, >200 mg/dL), and infection with a MRSA strain carrying the gene for staphylococcal enterotoxin P (sep). Receipt of an anti-MRSA medication had a significant protective effect. Conclusions. In an analysis controlling for host factors, colonization with MRSA carrying sep increased the risk of MRSA bacteremia. Identification of risk-adjusted genetic determinants of virulence may help to improve prediction of invasive disease and suggest new targets for therapeutic intervention. PMID:24041793

  2. Estimation of human dose of staphylococcal enterotoxin A from a large outbreak of staphylococcal food poisoning involving chocolate milk.

    PubMed

    Evenson, M L; Hinds, M W; Bernstein, R S; Bergdoll, M S

    1988-12-31

    An outbreak of gastroenteritis in a school district in the United States was determined to be staphylococcal food poisoning due to 2% chocolate milk containing staphylococcal enterotoxin A (SEA). Twelve one-half pint (approx 0.28 l) cartons of the 2% chocolate milk from this outbreak were analyzed for the quantity of SEA present in the milk. The amount of SEA in the cartons varied from 94 to 184 ng with the average being 144 ng (mean = 139 +/- 45). The attack rate for vomiting among those who consumed more than one carton was greater (38.3%) than among those who consumed only one carton (31.5%) with the highest attack rate among those who consumed three or more cartons (44.4%).

  3. PB2-Q591K Mutation Determines the Pathogenicity of Avian H9N2 Influenza Viruses for Mammalian Species

    PubMed Central

    Wang, Congrong; Lee, Horace Hok Yeung; Yang, Zi Feng; Mok, Chris Ka Pun; Zhang, Zhi

    2016-01-01

    Background Influenza A subtype H9N2 is widespread and prevalent in poultry. It has repeatedly transmitted zoonotically to cause mild influenza-like illness in humans and is regarded as a potential pandemic candidate. In additon, the six internal genes of H7N9 and H10N8 viruses which caused infection in human in China as well as some of the highly pathogenic H5N1 strains are origined from H9N2. Previous studies have shown that the mammalian adaptation PB2-Q591K contributes to the pathogenicity of H5N1 and H7N9 viruses. However, the role of the PB2-Q591K mutation in H9N2 subtype is still not well understood. Methods To define and compare the individual role of PB2-Q591K substitution in the PB2 gene segment of H9N2 in relation to polymerase activity, replication competence and the pathogenicity using in vitro and in vivo models. Results The PB2-Q591K mutation in H9N2 virus enhanced the polymerase activity and virus replication in human NHBE cells when compared to the wild type strain. Mice infected with the PB2 mutant showed significant weight loss, higher virus replication and immune responses in the lungs. Conclusions Our evidences suggest that the PB2-Q591K, in addition to the -E627K mutation in H9N2 enhanced the pathogenicity in mammalian host. PMID:27684944

  4. Following the infection process of vibriosis in Manila clam (Ruditapes philippinarum) larvae through GFP-tagged pathogenic Vibrio species.

    PubMed

    Dubert, Javier; Nelson, David R; Spinard, Edward J; Kessner, Linda; Gomez-Chiarri, Marta; da Costa, Fiz; Prado, Susana; Barja, Juan L

    2016-01-01

    Vibriosis represents the main bottleneck for the larval production process in shellfish aquaculture. While the signs of this disease in bivalve larvae are well known, the infection process by pathogenic Vibrio spp. during episodes of vibriosis has not been elucidated. To investigate the infection process in bivalves, the pathogens of larvae as V. tubiashii subsp. europaensis, V. neptunius and V. bivalvicida were tagged with green fluorescent protein (GFP). Larvae of Manila clam (Ruditapes philippinarum) were inoculated with the GFP-labeled pathogens in different infection assays and monitored by microscopy. Manila clam larvae infected by distinct GFP-tagged Vibrio spp. in different challenges showed the same progression in the infection process, defining three infection stages. GFP-tagged Vibrio spp. were filtered by the larvae through the vellum and entered in the digestive system through the esophagus and stomach and colonized the digestive gland and particularly the intestine, where they proliferated during the first 2h of contact (Stage I), suggesting a chemotactic response. Then, GFP-tagged Vibrio spp. expanded rapidly to the surrounding organs in the body cavity from the dorsal to ventral region (Stage II; 6-8h), colonizing the larvae completely at the peak of infection (Stage III) (14-24h). Results demonstrated for the first time that the vibriosis is asymptomatic in Manila clam larvae during the early infection stages. Thus, the early colonization and the rapid proliferation of Vibrio pathogens within the body cavity supported the sudden and fatal effect of the vibriosis, since the larvae exhibited the first signs of disease when the infection process is advanced. As a first step in the elucidation of the potential mechanisms of bacterial pathogenesis in bivalve larvae the enzymatic activities of the extracellular products released from the wild type V. neptunius, V. tubiashii subsp. europaensis and V. bivalvicida were determined and their cytotoxicity was

  5. Pathogenicity Tests on Nine Mosquito Species and Several Non-target Organisms with Strelkovimermis spiculatus (Nemata Mermithidae)

    PubMed Central

    Becnel, James J.; Johnson, Margaret A.

    1998-01-01

    Nine species of mosquitoes and several species of non-target aquatic organisms were tested for susceptibility to the mernaithid nematode, Strelkovimermis spiculatus. All species of Anopheles, Aedes, Culex, and Toxorhynchites exposed to S. spiculatus were susceptible. Of the nine mosquito species tested, C. pipiens quinquefasciatus had the greatest tolerance to initial invasion and the highest percent infection of those that survived. High levels of infection were also achieved with Aedes taeniorhynchus and A. albopictus, but these mosquitoes were significantly less tolerant to parasitism than C. pipiens quinquefasciatus. Strelkovimermis spiculatus did not infect or develop in any of the non-target hosts tested. PMID:19274233

  6. Presence and persistence of wastewater pathogen Escherichia coli O157:H7 in hydroponic reactors of treatment wetland species.

    PubMed

    VanKempen-Fryling, R J; Stein, O R; Camper, A K

    2015-01-01

    Treatment wetlands (TWs) efficiently remove many pollutants including a several log order reduction of pathogens from influent to effluent; however, there is evidence to suggest that pathogen cells are sequestered in a subsurface wetland and may remain viable months after inoculation. Escherichia coli is a common pathogen in domestic and agricultural wastewater and the O157:H7 strain causes most environmental outbreaks in the United States. To assess attachment of E. coli to the TW rhizosphere, direct measurements of E. coli levels were taken. Experiments were performed in chemostats containing either Teflon nylon as an abiotic control or roots of Carex utriculata or Schoenoplectus acutus. Flow of simulated wastewater through the chemostat was set to maintain a 2 hour residence time. The influent was inoculated with E. coli O157:H7 containing DsRed fluorescent protein. Root samples were excised and analyzed via epifluorescent microscopy. E. coli O157:H7 was detected on the root surface at 2 hours after inoculation, and were visible as single cells. Microcolonies began forming at 24 hours post-inoculation and were detected for up to 1 week post-inoculation. Image analysis determined that the number of microcolonies with >100 cells increased 1 week post-inoculation, confirming that E. coli O157:H7 is capable of growth within biofilms surrounding wetland plant roots.

  7. Multilocus Genotyping and Molecular Phylogenetics Resolve a Novel Head Blight Pathogen within the Fusarium graminearum Species Complex from Ethiopia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A survey of Fusarium head blight (FHB)-contaminated wheat in Ethiopia recovered 31 isolates resembling members of the Fusarium graminearum species complex. Results of a multilocus genotyping (MLGT) assay for FHB species and trichothecene chemotype determination suggested that 22 of these isolates m...

  8. Systematics of Plant-Pathogenic and Related Streptomyces Species Based on Phylogenetic Analyses of Multiple Gene Loci

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 10 species of Streptomyces implicated as the etiological agents in scab disease of potatoes or soft rot disease of sweet potatoes are distributed among 7 different phylogenetic clades in analyses based on 16S rRNA gene sequences, but high sequence similarity of this gene among Streptomyces speci...

  9. The Diaporthe sojae species complex: phylogenetic re-assessment of pathogens associated with soybean, cucurbits and other field crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytopathogenic species of Diaporthe are associated with the serious diseases including seed decay, pod and stem blight and stem canker of soybean leading to considerable loss of crop production worldwide. Accurate identification of the species that cause these diseases has been difficult due to the...

  10. Staphylococcal superantigens in colonization and disease.

    PubMed

    Xu, Stacey X; McCormick, John K

    2012-01-01

    Superantigens (SAgs) are a family of potent immunostimulatory exotoxins known to be produced by only a few bacterial pathogens, including Staphylococcus aureus. More than 20 distinct SAgs have been characterized from different S. aureus strains and at least 80% of clinical strains harbor at least one SAg gene, although most strains encode many. SAgs have been classically associated with food poisoning and toxic shock syndrome (TSS), for which these toxins are the causative agent. TSS is a potentially fatal disease whereby SAg-mediated activation of T cells results in overproduction of cytokines and results in systemic inflammation and shock. Numerous studies have also shown a possible role for SAgs in other diseases such as Kawasaki disease (KD), atopic dermatitis (AD), and chronic rhinosinusitis (CRS). There is also now a rich understanding of the mechanisms of action of SAgs, as well as their structures and function. However, we have yet to discover what purpose SAgs play in the life cycle of S. aureus, and why such a wide array of these toxins exists. This review will focus on recent developments within the SAg field in terms of the molecular biology of these toxins and their role in both colonization and disease.

  11. Direct Analysis and Identification of Pathogenic Lichtheimia Species by Matrix-Assisted Laser Desorption Ionization–Time of Flight Analyzer-Mediated Mass Spectrometry

    PubMed Central

    Schrödl, Wieland; Heydel, Tilo; Schwartze, Volker U.; Hoffmann, Kerstin; Große-Herrenthey, Anke; Walther, Grit; Alastruey-Izquierdo, Ana; Rodriguez-Tudela, Juan Luis; Olias, Philipp; Jacobsen, Ilse D.; de Hoog, G. Sybren

    2012-01-01

    Zygomycetes of the order Mucorales can cause life-threatening infections in humans. These mucormycoses are emerging and associated with a rapid tissue destruction and high mortality. The resistance of Mucorales to antimycotic substances varies between and within clinically important genera such as Mucor, Rhizopus, and Lichtheimia. Thus, an accurate diagnosis before onset of antimycotic therapy is recommended. Matrix-assisted laser desorption ionization (MALDI)–time of flight (TOF) mass spectrometry (MS) is a potentially powerful tool to rapidly identify infectious agents on the species level. We investigated the potential of MALDI-TOF MS to differentiate Lichtheimia species, one of the most important agents of mucormycoses. Using the Bruker Daltonics FlexAnalysis (version 3.0) software package, a spectral database library with m/z ratios of 2,000 to 20,000 Da was created for 19 type and reference strains of clinically relevant Zygomycetes of the order Mucorales (12 species in 7 genera). The database was tested for accuracy by use of 34 clinical and environmental isolates of Lichtheimia comprising a total of five species. Our data demonstrate that MALDI-TOF MS can be used to clearly discriminate Lichtheimia species from other pathogenic species of the Mucorales. Furthermore, the method is suitable to discriminate species within the genus. The reliability and robustness of the MALDI-TOF-based identification are evidenced by high score values (above 2.3) for the designation to a certain species and by moderate score values (below 2.0) for the discrimination between clinically relevant (Lichtheimia corymbifera, L. ramosa, and L. ornata) and irrelevant (L. hyalospora and L. sphaerocystis) species. In total, all 34 strains were unequivocally identified by MALDI-TOF MS with score values of >1.8 down to the generic level, 32 out of 34 of the Lichtheimia isolates (except CNM-CM 5399 and FSU 10566) were identified accurately with score values of >2 (probable species

  12. Identifying the emerging human pathogen Scedosporium prolificans by using a species-specific monoclonal antibody that binds to the melanin biosynthetic enzyme tetrahydroxynaphthalene reductase.

    PubMed

    Thornton, Christopher R; Ryder, Lauren S; Le Cocq, Kate; Soanes, Darren M

    2015-04-01

    The dematiaceous (melanized) fungus Scedosporium prolificans is an emerging and frequently fatal pathogen of immunocompromised humans and which, along with the closely related fungi Pseudallescheria boydii, Scedosporium apiospermum and S. aurantiacum in the Pseudallescheria-Scedosporium complex, is a contributing aetiology to tsunami lung and central nervous system infections in near-drowning victims who have aspirated water laden with spores. At present, the natural habitat of the fungus is largely unknown, and accurate detection methods are needed to identify environmental reservoirs of infectious propagules. In this study, we report the development of a monoclonal antibody (mAb) (CA4) specific to S. prolificans, which does not cross-react with closely related fungi in the Pseudallescheria-Scedosporium complex or with a wide range of mould and yeast species pathogenic to humans. Using genome sequencing of a soil isolate and targeted gene disruption of the CA4 antigen-encoding gene, we show that mAb CA4 binds to the melanin-biosynthetic enzyme tetrahydroxynaphthalene reductase. Enzyme-deficient mutants produce orange-brown or green-brown spore suspensions compared with the black spore suspension of the wild-type strain. Using mAb CA4 and a mAb (HG12) specific to the related fungi P. boydii, P. apiosperma, S. apiospermum and S. aurantiacum, we demonstrate how the mAbs can be used in combination with a semiselective isolation procedure to track these opportunistic pathogens in environmental samples containing mixed populations of human pathogenic fungi. Specificity of mAb CA4 was confirmed by sequencing of the internally transcribed spacer 1 (ITS1)-5.8S-ITS2 rRNA-encoding regions of fungi isolated from estuarine muds.

  13. APOBEC3G polymorphism as a selective barrier to cross-species transmission and emergence of pathogenic SIV and AIDS in a primate host.

    PubMed

    Krupp, Annabel; McCarthy, Kevin R; Ooms, Marcel; Letko, Michael; Morgan, Jennifer S; Simon, Viviana; Johnson, Welkin E

    2013-01-01

    Cellular restriction factors, which render cells intrinsically resistant to viruses, potentially impose genetic barriers to cross-species transmission and emergence of viral pathogens in nature. One such factor is APOBEC3G. To overcome APOBEC3G-mediated restriction, many lentiviruses encode Vif, a protein that targets APOBEC3G for degradation. As with many restriction factor genes, primate APOBEC3G displays strong signatures of positive selection. This is interpreted as evidence that the primate APOBEC3G locus reflects a long-term evolutionary "arms-race" between retroviruses and their primate hosts. Here, we provide direct evidence that APOBEC3G has functioned as a barrier to cross-species transmission, selecting for viral resistance during emergence of the AIDS-causing pathogen SIVmac in captive colonies of Asian macaques in the 1970s. Specifically, we found that rhesus macaques have multiple, functionally distinct APOBEC3G alleles, and that emergence of SIVmac and simian AIDS required adaptation of the virus to evade APOBEC3G-mediated restriction. Our evidence includes the first comparative analysis of APOBEC3G polymorphism and function in both a reservoir and recipient host species (sooty mangabeys and rhesus macaques, respectively), and identification of adaptations unique to Vif proteins of the SIVmac lineage that specifically antagonize rhesus APOBEC3G alleles. By demonstrating that interspecies variation in a known restriction factor selected for viral counter-adaptations in the context of a documented case of cross-species transmission, our results lend strong support to the evolutionary "arms-race" hypothesis. Importantly, our study confirms that APOBEC3G divergence can be a critical determinant of interspecies transmission and emergence of primate lentiviruses, including viruses with the potential to infect and spread in human populations.

  14. Comparative Genomics of H. pylori and Non-Pylori Helicobacter Species to Identify New Regions Associated with Its Pathogenicity and Adaptability

    PubMed Central

    Lu, Qun-Feng; Li, Song-Bo; Wang, Ju-Ping; Chen, Yu-Li

    2016-01-01

    The genus Helicobacter is a group of Gram-negative, helical-shaped pathogens consisting of at least 36 bacterial species. Helicobacter pylori (H. pylori), infecting more than 50% of the human population, is considered as the major cause of gastritis, peptic ulcer, and gastric cancer. However, the genetic underpinnings of H. pylori that are responsible for its large scale epidemic and gastrointestinal environment adaption within human beings remain unclear. Core-pan genome analysis was performed among 75 representative H. pylori and 24 non-pylori Helicobacter genomes. There were 1173 conserved protein families of H. pylori and 673 of all 99 Helicobacter genus strains. We found 79 genome unique regions, a total of 202,359bp, shared by at least 80% of the H. pylori but lacked in non-pylori Helicobacter species. The operons, genes, and sRNAs within the H. pylori unique regions were considered as potential ones associated with its pathogenicity and adaptability, and the relativity among them has been partially confirmed by functional annotation analysis. However, functions of at least 54 genes and 10 sRNAs were still unclear. Our analysis of protein-protein interaction showed that 30 genes within them may have the cooperation relationship. PMID:28078297

  15. Surface plasmon resonance (SPR) detection of Staphylococcal Enterotoxin A in food samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An automated and rapid method for detection of staphylococcal enterotoxins (SE) is needed. A sandwich assay was developed using a surface plasmon resonance (SPR) biosensor for detection of staphylococcal enterotoxin A (SEA) at subpicomolar concentration. Assay conditions were optimized for capturing...

  16. Detection of antibody to staphylococcal lipoteichoic acid with a microenzyme-linked immunosorbent assay.

    PubMed Central

    Carruthers, M M; Jenkins, K E; Kabat, W J; Buranosky, T

    1984-01-01

    Sera from individuals with Staphylococcus aureus endocarditis and osteomyelitis and from some individuals with other forms of gram-positive endocarditis yielded higher readings in a microenzyme-linked immunosorbent assay against lipoteichoic acid from S. aureus than did sera from individuals with other types of serious staphylococcal infection or non-staphylococcal osteomyelitis, or from unselected inpatients. PMID:6715523

  17. Staph ID/R: a rapid method for determining staphylococcus species identity and detecting the mecA gene directly from positive blood culture.

    PubMed

    Pasko, Chris; Hicke, Brian; Dunn, John; Jaeckel, Heidi; Nieuwlandt, Dan; Weed, Diane; Woodruff, Evelyn; Zheng, Xiaotian; Jenison, Robert

    2012-03-01

    Rapid diagnosis of staphylococcal bacteremia directs appropriate antimicrobial therapy, leading to improved patient outcome. We describe herein a rapid test (<75 min) that can identify the major pathogenic strains of Staphylococcus to the species level as well as the presence or absence of the methicillin resistance determinant gene, mecA. The test, Staph ID/R, combines a rapid isothermal nucleic acid amplification method, helicase-dependent amplification (HDA), with a chip-based array that produces unambiguous visible results. The analytic sensitivity was 1 CFU per reaction for the mecA gene and was 1 to 250 CFU per reaction depending on the staphylococcal species present in the positive blood culture. Staph ID/R has excellent specificity as well, with no cross-reactivity observed. We validated the performance of Staph ID/R by testing 104 frozen clinical positive blood cultures and comparing the results with rpoB gene or 16S rRNA gene sequencing for species identity determinations and mecA gene PCR to confirm mecA gene results. Staph ID/R agreed with mecA gene PCR for all samples and agreed with rpoB/16S rRNA gene sequencing in all cases except for one sample that contained a mixture of two staphylococcal species, one of which Staph ID/R correctly identified, for an overall agreement of 99.0% (P < 0.01). Staph ID/R could potentially be used to positively affect patient management for Staphylococcus-mediated bacteremia.

  18. Elucidation of bacteria found in car interiors and strategies to reduce the presence of potential pathogens.

    PubMed

    Stephenson, Rachel E; Gutierrez, Daniel; Peters, Cindy; Nichols, Mark; Boles, Blaise R

    2014-01-01

    The human microbiome is influenced by a number of factors, including environmental exposure to microbes. Because many humans spend a large amount of time in built environments, it can be expected that the microbial ecology of these environments will influence the human microbiome. In an attempt to further understand the microbial ecology of built environments, the microbiota of car interiors was analyzed using culture dependent and culture independent methods. While it was found that the number and type of bacteria varied widely among the cars and sites tested, Staphylococcus and Propionibacterium were nearly always the dominant genera found at the locations sampled. Because Staphylococcus is of particular concern to human health, the characteristics of this genus found in car interiors were investigated. Staphylococcus epidermidis, S. aureus, and S. warnerii were the most prevalent staphylococcal species found, and 22.6% of S. aureus strains isolated from shared community vehicles were resistant to methicillin. The reduction in the prevalence of pathogenic bacteria in cars by using silver-based antimicrobial surface coatings was also evaluated. Coatings containing 5% silver ion additives were applied to steering wheels, placed in cars for five months and were found to eliminate the presence of culturable pathogenic bacteria recovered from these sites relative to controls. Together, these results provide new insight into the microbiota found in an important built environment, the automobile, and potential strategies for controlling the presence of human pathogens.

  19. Staphylococcal bicomponent pore-forming toxins: targets for prophylaxis and immunotherapy.

    PubMed

    Aman, M Javad; Adhikari, Rajan P

    2014-03-04

    Staphylococccus aureus represents one of the most challenging human pathogens as well as a common colonizer of human skin and mucosal surfaces. S. aureus causes a wide range of diseases from skin and soft tissue infection (SSTI) to debilitating and life-threatening conditions such as osteomyelitis, endocarditis, and necrotizing pneumonia. The range of diseases reflects the remarkable diversity of the virulence factors produced by this pathogen, including surface antigens involved in the establishment of infection and a large number of toxins that mediate a vast array of cellular responses. The staphylococcal toxins are generally believed to have evolved to disarm the innate immune system, the first line of defense against this pathogen. This review focuses on recent advances on elucidating the biological functions of S. aureus bicomponent pore-forming toxins (BCPFTs) and their utility as targets for preventive and therapeutic intervention. These toxins are cytolytic to a variety of immune cells, primarily neutrophils, as well as cells with a critical barrier function. The lytic activity of BCPFTs towards immune cells implies a critical role in immune evasion, and a number of epidemiological studies and animal experiments relate these toxins to clinical disease, particularly SSTI and necrotizing pneumonia. Antibody-mediated neutralization of this lytic activity may provide a strategy for development of toxoid-based vaccines or immunotherapeutics for prevention or mitigation of clinical diseases. However, certain BCPFTs have been proposed to act as danger signals that may alert the immune system through an inflammatory response. The utility of a neutralizing vaccination strategy must be weighed against such immune-activating potential.

  20. Differentiation of toxigenic Staphylococcus aureus in staphylococcal isolates from prepared and frozen foods by combined arbitrarily primed polymerase chain reaction and DNA probe.

    PubMed

    Córdoba, Maria G; Jordano, Rafael; Aranda, Emilio; Benito, Maria J; Córdoba, Juan J

    2003-06-01

    In prepared and frozen flamenquín and hake fish fingers Staphylococcus aureus as sanitary hazards have been detected. In the present work, a combined method that includes an arbitrarily primed PCR (AP-PCR) and a mixed DNA probe hybridisation designed for the enterotoxigenic genes sea, seb, sec, and sed will be assayed to differentiate enterotoxigenic S. aureus from other staphylococcal species isolated during the processing of prepared and frozen foods. From the protocols tested for the AP-PCR, the highest number of amplification bands showing the best resolution was achieved at 30 degrees C annealing and 35 degrees C extension temperatures. Several staphylococci identified by a biochemical test as S. aureus showed in the AP-PCR analysis different banding patterns to the references S. aureus. The isolates, were investigated by slot blot hybridisation for genes encoding A, B, C, and D staphylococcal enterotoxins to determine their enterotoxigenic potential. Several isolates characterised by the AP-PCR analysis as S. aureus hybridised with the DNA probe mixture. The combined AP-PCR and DNA probe hybridisation assayed was able to differentiate toxigenic S. aureus from other staphylococcal species from prepared and frozen foods. This method could be considered as microbial quality assurance in these products.

  1. Characterization and biological properties of a new staphylococcal exotoxin

    PubMed Central

    1994-01-01

    Staphylococcus aureus strain D4508 is a toxic shock syndrome toxin 1- negative clinical isolate from a nonmenstrual case of toxic shock syndrome (TSS). In the present study, we have purified and characterized a new exotoxin from the extracellular products of this strain. This toxin was found to have a molecular mass of 25.14 kD by mass spectrometry and an isoelectric point of 5.65 by isoelectric focusing. We have also cloned and sequenced its corresponding genomic determinant. The DNA sequence encoding the mature protein was found to be 654 base pairs and is predicted to encode a polypeptide of 218 amino acids. The deduced protein contains an NH2-terminal sequence identical to that of the native protein. The calculated molecular weight (25.21 kD) of the recombinant mature protein is also consistent with that of the native molecules. When injected intravenously into rabbits, both the native and recombinant toxins induce an acute TSS-like illness characterized by high fever, hypotension, diarrhea, shock, and in some cases death, with classical histological findings of TSS. Furthermore, the activity of the toxin is specifically enhanced by low quantities of endotoxins. The toxicity can be blocked by rabbit immunoglobulin G antibody specific for the toxin. Western blotting and DNA sequencing data confirm that the protein is a unique staphylococcal exotoxin, yet shares significant sequence homology with known staphylococcal enterotoxins, especially the SEA, SED, and SEE toxins. We conclude therefore that this 25-kD protein belongs to the staphylococcal enterotoxin gene family that is capable of inducing a TSS-like illness in rabbits. PMID:7964453

  2. Host responses associated with chronic staphylococcal mastitis in rabbits.

    PubMed

    Guerrero, Irene; Ferrian, Selena; Penadés, Mariola; García-Quirós, Ana; Pascual, Juan J; Selva, Laura; Viana, David; Corpa, Juan M

    2015-06-01

    Staphylococcal infection causes substantial economic losses in commercial rabbit production systems, and is associated with a wide variety of lesions, including chronic suppurative mastitis, which mainly affects breeding females. Most chronic staphylococcal infections in rabbits are caused by the ST121 lineage of Staphylococcus aureus, although other less common lineages, such as ST96 can also be involved. The aims of the present study were to characterise the host immune response in natural cases of mastitis in rabbits caused by S. aureus, to evaluate any relationship between peripheral and local immunity and to investigate the effect of different S. aureus genotypes on these immune responses. Adult multiparous female rabbits that were affected with chronic staphylococcal mastitis (n = 204) were enrolled into the study. Histological and immunohistochemical evaluations of mammary glands were undertaken, as well as flow cytometric analyses of blood. S. aureus isolates from the mammary glands were identified by multilocus sequence typing. Differences in the number of infiltrating cells were detected, depending on the type of pathology, with more immature lesions demonstrating greater cellularity, characterised by greater numbers of T lymphocytes, macrophages and plasma cells. A relationship was seen between the cells in blood and mammary tissues, the most notable being the positive correlation between monocytes and tissue macrophages. When glands were infected with ST96 strains, fewer granulocytes (P < 0.01) and greater numbers of B cells (P < 0.01), T cells (P < 0.001), CD4(+) T cells (P < 0.001) and CD8(+) T cells (P < 0.01) were detected, compared with mammary glands that were infected by ST121 strains of S. aureus.

  3. Replication of staphylococcal plasmid pT48.

    PubMed

    Catchpole, I R; Dyke, K G

    1992-02-01

    Insertion of a synthetic DNA linker into the repL gene of staphylococcal plasmid pT48 inactivates the replication system. This defect can be complemented in trans by the presence of a pT48 repL gene, but not by the rep genes of the related Staphylococcus areus plasmids pSN2 and pOX1000. Comparison of the sequences of the three replication proteins indicates that specificity may be determined by a putative helix-turn-helix region.

  4. Defining species boundaries in the genus Phytophthora: the case of Phytophthora andina. A response to “Phytophthora andina sp. nov., a newly identified heterothallic pathogen of solanaceous hosts in the Andean highlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The newly described species Phytophthora andina is a relative of the potato late blight pathogen P. infestans. The formal P. andina species description is based on three types of evidence. First, the fact that these Ecuadorian isolates were found causing disease on different wild Solanum spp. that a...

  5. A Two-locus DNA Sequence Database for Typing Plant and Human Pathogens Within the Fusarium oxysporum Species Complex

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We constructed a two-locus database, comprising partial translation elongation factor (EF-1alpha) gene sequences and nearly full-length sequences of the nuclear ribosomal intergenic spacer region (IGS rDNA) for 850 isolates spanning the phylogenetic breadth of the Fusarium oxysporum species complex ...

  6. Staphylococcal adaptation to diverse physiologic niches: an overview of transcriptomic and phenotypic changes in different biological environments

    PubMed Central

    Dastgheyb, Sana S; Otto, Michael

    2015-01-01

    Host niches can differ strongly regarding, for example, oxygen tension, pH or nutrient availability. Staphylococcus aureus and other staphylococci are common colonizers of human epithelia as well as important human pathogens. The phenotypes that they show in different host environments, and the corresponding bacterial transcriptomes and proteomes, are currently under intense investigation. In this review, we examine the available literature describing staphylococcal phenotypes, such as expression of virulence factors, gross morphologic characteristics and growth patterns, in various physiological environments. Going forward, these studies will help researchers and clinicians to form an enhanced and more detailed picture of the interactions existing between the host and staphylococci as some of its most frequent colonizers and invaders. PMID:26584249

  7. Simultaneous identification of three highly pathogenic Eimeria species in rabbits using a multiplex PCR diagnostic assay based on ITS1-5.8S rRNA-ITS2 fragments.

    PubMed

    Yan, Wenchao; Wang, Wenlong; Wang, Tianqi; Suo, Xun; Qian, Weifeng; Wang, Shuai; Fan, Di

    2013-03-31

    Eimeria stiedai, E. intestinalis, and E. flavescens are highly pathogenic in rabbits, especially rabbits younger than 3 months. In this study, the complete ITS1-5.8S rRNA-ITS2 sequences of six rabbit Eimeria species, E. stiedai, E. intestinalis, E. flavescens, E. media, E. magna, and E. irresidua, were cloned with universal primers for the genus Eimeria and genomic DNA of LY and KF isolates as templates. These results revealed that both ITS1 and ITS2 sequences were specific to each Eimeria species in rabbits. A specific and sensitive multiplex PCR diagnostic assay based on polymorphic sites of ITS1 and ITS2 was developed and used to identify the three highly pathogenic species from rabbits, E. stiedai, E. intestinalis, and E. flavescens. Our findings provide a powerful tool for the clinical differentiation of highly pathogenic Eimeria species in rabbits and the study of the population genetics of rabbit coccidia.

  8. Pathogenicity of Two Species of Entomopathogenic Nematodes Against the Greenhouse Whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), in Laboratory and Greenhouse Experiments.

    PubMed

    Rezaei, Nastaran; Karimi, Javad; Hosseini, Mojtaba; Goldani, Morteza; Campos-Herrera, Raquel

    2015-03-01

    The greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) is a polyphagous pest in greenhouse crops. The efficacy of two entomopathogenic nematodes (EPN), Steinernema feltiae and Heterorhabditis bacteriophora, as biological control agents against T. vaporariorum was evaluated using two model crops typical of vegetable greenhouse productions: cucumber and pepper. Laboratory tests evaluated adults and second nymphal instars for pest susceptibility to different EPN species at different concentrations of infective juveniles (IJ; 0, 25, 50, 100, 150, 200, and 250 IJ per cm(2)); subsequent greenhouse trials against second nymphal instars on cucumber and pepper plants evaluated more natural conditions. Concentrations were applied in combination with Triton X-100 (0.1% v/v), an adjuvant for increasing nematode activity. In laboratory studies, both life stages were susceptible to infection by the two nematode species, but S. feltiae recorded a lower LC50 than H. bacteriophora for both insect stages. Similarly, in greenhouse experiments, S. feltiae required lower concentrations of IJ than H. bacteriophora to reach the same mortality in nymphs. In greenhouse trials, a significant difference was observed in the triple interaction among nematode species × concentration × plant. Furthermore, the highest mortality rate of the second nymphal instars of the T. vaporariorum was obtained from the application of S. feltiae concentrated to 250 IJ/cm(2) on cucumber (49 ± 1.23%). The general mortality caused by nematodes was significantly higher in cucumber than in pepper. These promising results support further investigation for the optimization of the best EPN species/concentration in combination with insecticides or adjuvants to reach a profitable control of this greenhouse pest.

  9. Pathogenicity of Two Species of Entomopathogenic Nematodes Against the Greenhouse Whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), in Laboratory and Greenhouse Experiments

    PubMed Central

    Rezaei, Nastaran; Karimi, Javad; Hosseini, Mojtaba; Goldani, Morteza; Campos-Herrera, Raquel

    2015-01-01

    The greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) is a polyphagous pest in greenhouse crops. The efficacy of two entomopathogenic nematodes (EPN), Steinernema feltiae and Heterorhabditis bacteriophora, as biological control agents against T. vaporariorum was evaluated using two model crops typical of vegetable greenhouse productions: cucumber and pepper. Laboratory tests evaluated adults and second nymphal instars for pest susceptibility to different EPN species at different concentrations of infective juveniles (IJ; 0, 25, 50, 100, 150, 200, and 250 IJ per cm2); subsequent greenhouse trials against second nymphal instars on cucumber and pepper plants evaluated more natural conditions. Concentrations were applied in combination with Triton X-100 (0.1% v/v), an adjuvant for increasing nematode activity. In laboratory studies, both life stages were susceptible to infection by the two nematode species, but S. feltiae recorded a lower LC50 than H. bacteriophora for both insect stages. Similarly, in greenhouse experiments, S. feltiae required lower concentrations of IJ than H. bacteriophora to reach the same mortality in nymphs. In greenhouse trials, a significant difference was observed in the triple interaction among nematode species × concentration × plant. Furthermore, the highest mortality rate of the second nymphal instars of the T. vaporariorum was obtained from the application of S. feltiae concentrated to 250 IJ/cm2 on cucumber (49 ± 1.23%). The general mortality caused by nematodes was significantly higher in cucumber than in pepper. These promising results support further investigation for the optimization of the best EPN species/concentration in combination with insecticides or adjuvants to reach a profitable control of this greenhouse pest. PMID:25861117

  10. Elucidating the Diversity of Aquatic Microdochium and Trichoderma Species and Their Activity against the Fish Pathogen Saprolegnia diclina

    PubMed Central

    Liu, Yiying; Zachow, Christin; Raaijmakers, Jos M.; de Bruijn, Irene

    2016-01-01

    Animals and plants are increasingly threatened by emerging fungal and oomycete diseases. Amongst oomycetes, Saprolegnia species cause population declines in aquatic animals, especially fish and amphibians, resulting in significant perturbation in biodiversity, ecological balance and food security. Due to the prohibition of several chemical control agents, novel sustainable measures are required to control Saprolegnia infections in aquaculture. Previously, fungal community analysis by terminal restriction fragment length polymorphism (T-RFLP) revealed that the Ascomycota, specifically the genus Microdochium, was an abundant fungal phylum associated with salmon eggs from a commercial fish farm. Here, phylogenetic analyses showed that most fungal isolates obtained from salmon eggs were closely related to Microdochium lycopodinum/Microdochium phragmitis and Trichoderma viride species. Phylogenetic and quantitative PCR analyses showed both a quantitative and qualitative difference in Trichoderma population between diseased and healthy salmon eggs, which was not the case for the Microdochium population. In vitro antagonistic activity of the fungi against Saprolegnia diclina was isolate-dependent; for most Trichoderma isolates, the typical mycoparasitic coiling around and/or formation of papilla-like structures on S. diclina hyphae were observed. These results suggest that among the fungal community associated with salmon eggs, Trichoderma species may play a role in Saprolegnia suppression in aquaculture. PMID:26805821

  11. Elucidating the Diversity of Aquatic Microdochium and Trichoderma Species and Their Activity against the Fish Pathogen Saprolegnia diclina.

    PubMed

    Liu, Yiying; Zachow, Christin; Raaijmakers, Jos M; de Bruijn, Irene

    2016-01-21

    Animals and plants are increasingly threatened by emerging fungal and oomycete diseases. Amongst oomycetes, Saprolegnia species cause population declines in aquatic animals, especially fish and amphibians, resulting in significant perturbation in biodiversity, ecological balance and food security. Due to the prohibition of several chemical control agents, novel sustainable measures are required to control Saprolegnia infections in aquaculture. Previously, fungal community analysis by terminal restriction fragment length polymorphism (T-RFLP) revealed that the Ascomycota, specifically the genus Microdochium, was an abundant fungal phylum associated with salmon eggs from a commercial fish farm. Here, phylogenetic analyses showed that most fungal isolates obtained from salmon eggs were closely related to Microdochium lycopodinum/Microdochium phragmitis and Trichoderma viride species. Phylogenetic and quantitative PCR analyses showed both a quantitative and qualitative difference in Trichoderma population between diseased and healthy salmon eggs, which was not the case for the Microdochium population. In vitro antagonistic activity of the fungi against Saprolegnia diclina was isolate-dependent; for most Trichoderma isolates, the typical mycoparasitic coiling around and/or formation of papilla-like structures on S. diclina hyphae were observed. These results suggest that among the fungal community associated with salmon eggs, Trichoderma species may play a role in Saprolegnia suppression in aquaculture.

  12. Amygdaloid signature of peripheral immune activation by bacterial lipopolysaccharide or staphylococcal enterotoxin B.

    PubMed

    Prager, Geraldine; Hadamitzky, Martin; Engler, Andrea; Doenlen, Raphael; Wirth, Timo; Pacheco-López, Gustavo; Krügel, Ute; Schedlowski, Manfred; Engler, Harald

    2013-03-01

    Activated immune cells produce soluble mediators that not only coordinate local and systemic immune responses but also act on the brain to initiate behavioral, neuroendocrine and metabolic adaptations. Earlier studies have shown that the amygdala, a group of nuclei located in the medial temporal lobe, is engaged in the central processing of afferent signals from the peripheral immune system. Here, we compared amygdaloid responses to lipopolysaccharide (LPS) and staphylococcal enterotoxin B (SEB), two prototypic bacterial products that elicit distinct immune responses. Intraperitoneal administration of LPS (0.1 mg/kg) or SEB (1 mg/kg) in adult rats induced substantial increases in amygdaloid neuronal activity as measured by intracerebral electroencephalography and c-fos gene expression. Amygdaloid neuronal activation was accompanied by an increase in anxiety-related behavior in the elevated plus-maze test. However, only treatment with LPS, but not SEB, enhanced amygdaloid IL-1β and TNF-α mRNA expression. This supports the view of the immune system as a sensory organ that recognizes invading pathogens and rapidly relays this information to the brain, independent of the nature of the immune response induced. The observation that neuronal and behavioral responses to peripheral immune challenges are not necessarily accompanied by increased brain cytokine expression suggests that cytokines are not the only factors driving sickness-related responses in the CNS.

  13. High-dose Daptomycin Therapy for Staphylococcal Endocarditis and When to Apply It

    PubMed Central

    Smith, Jordan R.; Claeys, Kimberly; Barber, Katie E.; Rybak, Michael J.

    2014-01-01

    Infective endocarditis (IE) continues to present a large burden to the healthcare system. Staphylococcus aureus, the leading pathogen associated with the disease, has always proven difficult to treat. Increasing numbers of S. aureus isolates are demonstrating reduced susceptibility to vancomycin, and therapeutic options are limited. Daptomycin is frequently employed when vancomycin therapy proves unsuccessful or when vancomycin MIC values rise above 1 mg/L. Currently, daptomycin is FDA-approved at a dose of 6 mg/kg/day for the treatment of S. aureus bacteremia and associated right-sided endocarditis. However, numerous in vitro and clinical studies suggest that daptomycin doses up to 12 mg/kg/day may provide improved efficacy and resistance prevention. Additionally, high-dose daptomycin has demonstrated excellent safety. Together, these data suggest a role for high-dose daptomycin in staphylococcal IE patients who are severely ill, previously failed therapy with vancomycin, or possess a S. aureus isolate with an elevated vancomycin MIC. PMID:25165017

  14. [Description of a staphylococcal alimentary poisoning outbreak in Las Rosas, Santa Fe Province, Argentina].

    PubMed

    Brizzio, Aníbal A; Tedeschi, Fabián A; Zalazar, Fabián E

    2011-01-01

    On February 2008, a suspected foodborne outbreak was reported in Las Rosas (Santa Fe Province, Argentina). The formal procedures indicated that an undetermined number of individuals had experienced food poisoning following consumption of vegetable cannelloni bought at a local shop. The manufacturer establishment was audited. Samples from the suspected food, as well as environmental samples and swabs from food handlers were obtained and involved subjects were interviewed. Remnants of ingested food were also obtained. Routine microbiological procedures of the foodborne outbreak revealed the presence of coagulase positive S. aureus subspecies aureus in samples from ingested and raw food, and from manipulators. Indicator microorganisms did not show significant levels and no other foodborne pathogen was isolated. Presence of staphylococcal enterotoxin-producing genes was subsequently investigated, and a positive result for enterotoxin B was shown in S. aureus strains isolated from a food handler as well as from food linked to the outbreak Moreover, these isolates showed 100% similarity by SmaI-PFGE. Timely notification together with coordinated sanitary measures and the availability of appropriate laboratory tools allowed to interrupt the chain of disease transmission by identifying risk and protective factors.

  15. Staphylococcal chromosomal cassettes mec (SCCmec): A mobile genetic element in methicillin-resistant Staphylococcus aureus.

    PubMed

    Liu, Junyan; Chen, Dingqiang; Peters, Brian M; Li, Lin; Li, Bing; Xu, Zhenbo; Shirliff, Mark E

    2016-12-01

    Considered to be a potential "superbug", methicillin-resistant Staphylococcus aureus (MRSA) has been one of the major recent infectious pathogens and thus poses a challenge to hospital infection control. The mobile genetic element staphylococcal chromosomal cassette mec (SCCmec) carries both the mecA or mecC gene, encoding for a novel specific penicillin-binding protein (PBP2a), and site-specific recombinase genes ccrAB or/and ccrC. In MRSA, the acquisition of SCCmec leads to the resistance to the β-lactam antibiotics. As SCCmec plays a core role in the antimicrobial resistance characteristics, molecular epidemiology and evolution of MRSA, a thorough summary and comprehensive understanding of the prevalence and structural characteristics of SCCmec may aid in global surveillance, implementation and investigation on MRSA isolates, as well as further development of preventive and therapeutic approaches. Consequently, this review is aimed at describing the history, prevalence, types and subtypes, and current typing methods of SCCmec, with the focus on the typical structures of the SCCmec cassette.

  16. Extracellular vesicles from Paracoccidioides pathogenic species transport polysaccharide and expose ligands for DC-SIGN receptors

    SciTech Connect

    da Silva, Roberta Peres; Heiss, Christian; Black, Ian; Azadi, Parastoo; Gerlach, Jared Q.; Travassos, Luiz R.; Joshi, Lokesh; Kilcoyne, Michelle; Puccia, Rosana

    2015-09-21

    Extracellular vesicles (EVs) mediate non-conventional transport of molecules across the fungal cell wall. We aimed at describing the carbohydrate composition and surface carbohydrate epitopes of EVs isolated from the pathogenic fungi Paracoccidioides brasiliensis and P. lutzii using standard procedures. Total EV carbohydrates were ethanol-precipitated from preparations depleted of lipids and proteins, then analyzed by chemical degradation, gas chromatography-mass spectrometry, nuclear magnetic resonance and size-exclusion chromatography. EV glycosyl residues of Glc, Man, and Gal comprised most probably two major components: a high molecular mass 4,6-α-glucan and a galactofuranosylmannan, possibly an oligomer, bearing a 2-α-Manp main chain linked to β-Galf (1,3) and α-Manp (1,6) end units. The results also suggested the presence of small amounts of a (1→6)- Manp polymer, (1→3)-glucan and (1→6)-glucan. Glycan microarrays allowed identification of EV surface lectin(s), while plant lectin microarray profiling revealed terminal Man and GlcNAc residues exposed at the EVs surface. Mammalian lectin microarray profiling showed that DC-SIGN receptors recognized surface carbohydrate in Paracoccidioides EVs. Our results suggest that oligosaccharides, cytoplasmic storage, and cell wall polysaccharides can be exported in fungal EVs, which also expose surface PAMPs and lectins. As a result, the role of these newly identified components in the interaction with the host remains to be unraveled.

  17. Biosecurity and Vector Behaviour: Evaluating the Potential Threat Posed by Anglers and Canoeists as Pathways for the Spread of Invasive Non-Native Species and Pathogens

    PubMed Central

    Anderson, Lucy G.; White, Piran C. L.; Stebbing, Paul D.; Stentiford, Grant D.; Dunn, Alison M.

    2014-01-01

    Invasive non-native species (INNS) endanger native biodiversity and are a major economic problem. The management of pathways to prevent their introduction and establishment is a key target in the Convention on Biological Diversity's Aichi biodiversity targets for 2020. Freshwater environments are particularly susceptible to invasions as they are exposed to multiple introduction pathways, including non-native fish stocking and the release of boat ballast water. Since many freshwater INNS and aquatic pathogens can survive for several days in damp environments, there is potential for transport between water catchments on the equipment used by recreational anglers and canoeists. To quantify this biosecurity risk, we conducted an online questionnaire with 960 anglers and 599 canoeists to investigate their locations of activity, equipment used, and how frequently equipment was cleaned and/or dried after use. Anglers were also asked about their use and disposal of live bait. Our results indicate that 64% of anglers and 78.5% of canoeists use their equipment/boat in more than one catchment within a fortnight, the survival time of many of the INNS and pathogens considered in this study and that 12% of anglers and 50% of canoeists do so without either cleaning or drying their kit between uses. Furthermore, 8% of anglers and 28% of canoeists had used their equipment overseas without cleaning or drying it after each use which could facilitate both the introduction and secondary spread of INNS in the UK. Our results provide a baseline against which to evaluate the effectiveness of future biosecurity awareness campaigns, and identify groups to target with biosecurity awareness information. Our results also indicate that the biosecurity practices of these groups must improve to reduce the likelihood of inadvertently spreading INNS and pathogens through these activities. PMID:24717714

  18. VraH Is the Third Component of the Staphylococcus aureus VraDEH System Involved in Gallidermin and Daptomycin Resistance and Pathogenicity

    PubMed Central

    Popella, Peter; Krauss, Sophia; Ebner, Patrick; Nega, Mulugeta; Deibert, Julia

    2016-01-01

    In bacteria, extracellular signals are transduced into the cell predominantly by two-component systems (TCSs) comprising a regulatory unit triggered by a specific signal. Some of the TCSs control executing units such as ABC transporters involved in antibiotic resistance. For instance, in Staphylococcus aureus, activation of BraSR leads to the upregulation of vraDE expression that encodes an ABC transporter playing a role in bacitracin and nisin resistance. In this study, we show that the small staphylococcal transmembrane protein VraH forms, together with VraDE, a three-component system. Although the expression of vraH in the absence of vraDE was sufficient to mediate low-level resistance, only this VraDEH entity conferred high-level resistance against daptomycin and gallidermin. In most staphylococcal genomes, vraH is located immediately downstream of vraDE, forming an operon, whereas in some species it is localized differently. In an invertebrate infection model, VraDEH significantly enhanced S. aureus pathogenicity. In analogy to the TCS connectors, VraH can be regarded as an ABC connector that modulates the activity of ABC transporters involved in antibiotic resistance. PMID:26856834

  19. Genetic differences accounting for evolution and pathogenicity of simian immunodeficiency virus from a sooty mangabey monkey after cross-species transmission to a pig-tailed macaque.

    PubMed Central

    Courgnaud, V; Lauré, F; Fultz, P N; Montagnier, L; Bréchot, C; Sonigo, P

    1992-01-01

    We determined the nucleotide sequences of two related isolates of simian immunodeficiency virus from the sooty mangabey monkey (SIVsmm) that exhibit dramatic differences in virulence. These isolates are separated by one experimental cross-species transmission, from sooty mangabey to pig-tailed macaque. The parental virus (SIVsmm9), nonpathogenic in the original host (sooty mangabeys), causes a chronic AIDS-like disease in macaques. In contrast, the variant virus (SIVsmmPBj14) induces an acute lethal disease in various macaque species and is also pathogenic for sooty mangabeys. The combination of necessary and sufficient mutations that determined the acutely lethal phenotype on the SIVsmm9 genetic background is included within a maximal set of 57 point mutations, plus two insertions located in the long terminal repeat (22 bp spanning an NF-kappa B-like enhancer element) and in the surface envelope glycoprotein (5 amino acids). Comparisons of synonymous and nonsynonymous nucleotide substitutions in the genome of SIVsmm indicated that selective pressures, probably due to the host immune response, favored amino acid changes in the envelope. This immunoevolutionary mechanism could explain the increase in diversity and the apparition of new virulent phenotypes after cross-species transmission. PMID:1727495

  20. Unique and conserved genome regions in Vibrio harveyi and related species in comparison with the shrimp pathogen Vibrio harveyi CAIM 1792.

    PubMed

    Espinoza-Valles, Iliana; Vora, Gary J; Lin, Baochuan; Leekitcharoenphon, Pimlapas; González-Castillo, Adrián; Ussery, Dave; Høj, Lone; Gomez-Gil, Bruno

    2015-09-01

    Vibrio harveyi CAIM 1792 is a marine bacterial strain that causes mortality in farmed shrimp in north-west Mexico, and the identification of virulence genes in this strain is important for understanding its pathogenicity. The aim of this work was to compare the V. harveyi CAIM 1792 genome with related genome sequences to determine their phylogenic relationship and explore unique regions in silico that differentiate this strain from other V. harveyi strains. Twenty-one newly sequenced genomes were compared in silico against the CAIM 1792 genome at nucleotidic and predicted proteome levels. The proteome of CAIM 1792 had higher similarity to those of other V. harveyi strains (78%) than to those of the other closely related species Vibrio owensii (67%), Vibrio rotiferianus (63%) and Vibrio campbellii (59%). Pan-genome ORFans trees showed the best fit with the accepted phylogeny based on DNA-DNA hybridization and multi-locus sequence analysis of 11 concatenated housekeeping genes. SNP analysis clustered 34/38 genomes within their accepted species. The pangenomic and SNP trees showed that V. harveyi is the most conserved of the four species studied and V. campbellii may be divided into at least three subspecies, supported by intergenomic distance analysis. blastp atlases were created to identify unique regions among the genomes most related to V. harveyi CAIM 1792; these regions included genes encoding glycosyltransferases, specific type restriction modification systems and a transcriptional regulator, LysR, reported to be involved in virulence, metabolism, quorum sensing and motility.

  1. The production of reactive oxygen species is a universal action mechanism of Amphotericin B against pathogenic yeasts and contributes to the fungicidal effect of this drug.

    PubMed

    Mesa-Arango, Ana Cecilia; Trevijano-Contador, Nuria; Román, Elvira; Sánchez-Fresneda, Ruth; Casas, Celia; Herrero, Enrique; Argüelles, Juan Carlos; Pla, Jesús; Cuenca-Estrella, Manuel; Zaragoza, Oscar

    2014-11-01

    Amphotericin B (AMB) is an antifungal drug that binds to ergosterol and forms pores at the cell membrane, causing the loss of ions. In addition, AMB induces the accumulation of reactive oxygen species (ROS), and although these molecules have multiple deleterious effects on fungal cells, their specific role in the action mechanism of AMB remains unknown. In this work, we studied the role of ROS in the action mechanism of AMB. We determined the intracellular induction of ROS in 44 isolates of different pathogenic yeast species (Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida krusei, Cryptococcus neoformans, and Cryptococcus gattii). We also characterized the production of ROS in AMB-resistant isolates. We found that AMB induces the formation of ROS in all the species tested. The inhibition of the mitochondrial respiratory chain by rotenone blocked the induction of ROS by AMB and provided protection from the killing action of the antifungal. Moreover, this phenomenon was absent in strains that displayed resistance to AMB. These strains showed an alteration in the respiration rate and mitochondrial membrane potential and also had higher catalase activity than that of the AMB-susceptible strains. Consistently, AMB failed to induce protein carbonylation in the resistant strains. Our data demonstrate that the production of ROS by AMB is a universal and important action mechanism that is correlated with the fungicidal effect and might explain the low rate of resistance to the molecule. Finally, these data provide an opportunity to design new strategies to improve the efficacy of this antifungal.

  2. Bruised Poultry Tissue as a Possible Source of Staphylococcal Infection

    PubMed Central

    Roskey, C. T.; Hamdy, M. K.

    1972-01-01

    Bacteriological analyses were made on 45 swab samples secured from hands of poultry workers on processing line, on 31 bruised and 15 normal poultry tissue samples, and on 15 swabs obtained from infected lacerations and exudates of abcesses on hands, arms, chest, and abdomen of poultry workers. A total of 170 Staphylococcus cultures were isolated from samples examined. These cultures were characterized morphologically and biochemically and then grouped into six distinct patterns. S. aureus was found in 86.6% of swab samples obtained from infected workers, in 40% of swabs from hands of workers who handle bruised birds, and in 38.7% of bruised tissues, and was absent from all samples obtained from hands of workers who do not handle bruised birds. All the coagulase-positive staphylococcal isolates were bacteriophage-typed, and the results showed that the same phage-type S. aureus was found in many poultry bruises and in infected lesions of poultry workers as well as on hands of workers who handle bruised birds. These results indicate that poultry bruises are a source of staphylococcal infection encountered among poultry workers. PMID:4553136

  3. Staphylococcal endogenous endophthalmitis in association with pyogenic vertebral osteomyelitis.

    PubMed

    Steeples, L R; Jones, N P

    2016-01-01

    PURPOSE To describe pyogenic vertebral osteomyelitis as a rare infection associated with endogenous endophthalmitis.METHODS A retrospective review of three patients with endogenous endophthalmitis and sepsis due to underlying Staphylococcal vertebral osteomyelitis presenting during a 21-month time period. The ophthalmic and systemic features and management and outcomes are presented.RESULTS One patient developed unilateral endophthalmitis with cervical spine osteomyelitis, Staphylococcus aureus being isolated from blood cultures. The second presented with bilateral endophthalmitis with disseminated Methicillin-resistant S. aureus (MRSA) infection, with thoracic and lumbar discitis and para-spinal abscesses. MRSA was cultured from vitreous, blood, and synovial fluid. Both patients received prolonged courses of intravenous antibiotics. Intravitreal antibiotic therapy was used in the second patient. Excellent visual and systemic outcomes were achieved in both cases with no ocular complications. The third patient developed lumbar osteomyelitis following spinal surgery and presented with disseminated S. aureus sepsis including unilateral endogenous endophthalmitis. Despite systemic antibiotics and intensive care the patient died.CONCLUSIONS Endogenous endophthalmitis should be suspected in septic patients developing eye symptoms. Endogenous endophthalmitis with staphylococcal bone infection is a rare but serious condition. Osteomyelitis should be considered as an infective source in any such patient reporting bone pain or reduced spinal mobility. Prompt investigation and treatment can achieve favourable visual and systemic outcomes.

  4. The pathogen-inducible promoter of defense-related LsGRP1 gene from Lilium functioning in phylogenetically distinct species of plants.

    PubMed

    Lin, Chia-Hua; Chen, Chao-Ying

    2017-01-01

    A suitable promoter greatly enhances the efficiency of target gene expression of plant molecular breeding and farming; however, only very few promoters are available for economically important non-graminaceous ornamental monocots. In this study, an 868-bp upstream region of defense-related LsGRP1 of Lilium, named PLsGRP1, was cloned by genome walking and proven to exhibit promoter activity in Nicotiana benthamiana and Lilium 'Stargazer' as assayed by agroinfiltration-based β-glucuronidase (GUS) expression system. Many putative biotic stress-, abiotic stress- and physiological regulation-related cis-acting elements were found in PLsGRP1. Serial deletion analysis of PLsGRP1 performed in Nicotiana tabacum var. Wisconsin 38 accompanied with types of treatments indicated that 868-bp PLsGRP1 was highly induced upon pathogen challenges and cold stress while the 131-bp 3'-end region of PLsGRP1 could be dramatically induced by many kinds of abiotic stresses, biotic stresses and phytohormone treatments. Besides, transient GUS expression in a fern, gymnosperms, monocots and dicots revealed good promotor activity of PLsGRP1 in many phylogenetically distinct plant species. Thus, pathogen-inducible PLsGRP1 and its 131-bp 3'-end region are presumed potential as tools for plant molecular breeding and farming.

  5. Prevalence of bacterial species in cats with clinical signs of lower urinary tract disease: recognition of Staphylococcus felis as a possible feline urinary tract pathogen.

    PubMed

    Litster, Annette; Moss, Susan M; Honnery, Mary; Rees, Bob; Trott, Darren J

    2007-03-31

    This study investigated the prevalence of bacterial pathogens of the urinary tract in Australian cats. Urine was collected by cystocentesis and subjected to urinalysis, bacterial culture and susceptibility testing. A total of 126 isolates were obtained from 107 culture-positive cats. Escherichia coli was most commonly isolated (37.3% of isolates) with the majority of isolates showing susceptibility to the 14 antimicrobials tested. Just over a quarter of isolates (27.0%) were Enterococcus faecalis, which showed resistance to cephalosporins and clindamycin. Staphylococcus felis, a previously unreported feline urinary tract pathogen which was susceptible to all antimicrobial agents tested, comprised 19.8% of the isolates. S. felis was significantly associated with urine that had a higher specific gravity (p=0.011) and pH (p=0.006) and was more likely to contain crystals (p=0.002) than urine from which other bacterial species were isolated. This is the first published study that associates the isolation of S. felis with clinical signs of lower urinary tract disease in cats.

  6. A whole genome analysis reveals the presence of a plant PR1 sequence in the potato pathogen Streptomyces scabies and other Streptomyces species.

    PubMed

    Armijos-Jaramillo, Vinicio; Santander-Gordón, Daniela; Soria, Rosa; Pazmiño-Betancourth, Mauro; Echeverría, María Cristina

    2016-08-12

    Streptomyces scabies is a common soil bacterium that causes scab symptoms in potatoes. Strong evidence indicates horizontal gene transfer (HGT) among bacteria has influenced the evolution of this plant pathogen and other Streptomyces spp. To extend the study of the HGT to the Streptomyces genus, we explored the effects of the inter-domain HGT in the S. scabies genome. We employed a semi-automatic pipeline based on BLASTp searches and phylogenetic reconstruction. The data show low impact of inter-domain HGT in the S. scabies genome; however, we found a putative plant pathogenesis related 1 (PR1) sequence in the genome of S. scabies and other species of the genus. It is possible that this gene could be used by S. scabies to out-compete other soil organisms.

  7. Four plant defensins from an indigenous South African Brassicaceae species display divergent activities against two test pathogens despite high sequence similarity in the encoding genes

    PubMed Central

    2011-01-01

    Background Plant defensins are an important component of the innate defence system of plants where they form protective antimicrobial barriers between tissue types of plant organs as well as around seeds. These peptides also have other activities that are important for agricultural applications as well as the medical sector. Amongst the numerous plant peptides isolated from a variety of plant species, a significant number of promising defensins have been isolated from Brassicaceae species. Here we report on the isolation and characterization of four defensins from Heliophila coronopifolia, a native South African Brassicaceae species. Results Four defensin genes (Hc-AFP1-4) were isolated with a homology based PCR strategy. Analysis of the deduced amino acid sequences showed that the peptides were 72% similar and grouped closest to defensins isolated from other Brassicaceae species. The Hc-AFP1 and 3 peptides shared high homology (94%) and formed a unique grouping in the Brassicaceae defensins, whereas Hc-AFP2 and 4 formed a second homology grouping with defensins from Arabidopsis and Raphanus. Homology modelling showed that the few amino acids that differed between the four peptides had an effect on the surface properties of the defensins, specifically in the alpha-helix and the loop connecting the second and third beta-strands. These areas are implicated in determining differential activities of defensins. Comparing the activities after recombinant production of the peptides, Hc-AFP2 and 4 had IC50 values of 5-20 μg ml-1 against two test pathogens, whereas Hc-AFP1 and 3 were less active. The activity against Botrytis cinerea was associated with membrane permeabilization, hyper-branching, biomass reduction and even lytic activity. In contrast, only Hc-AFP2 and 4 caused membrane permeabilization and severe hyper-branching against the wilting pathogen Fusarium solani, while Hc-AFP1 and 3 had a mild morphogenetic effect on the fungus, without any indication of

  8. Volatiles Emitted from Maize Ears Simultaneously Infected with Two Fusarium Species Mirror the Most Competitive Fungal Pathogen

    PubMed Central

    Sherif, Mohammed; Becker, Eva-Maria; Herrfurth, Cornelia; Feussner, Ivo; Karlovsky, Petr; Splivallo, Richard

    2016-01-01

    Along with barley and rice, maize provides staple food for more than half of the world population. Maize ears are regularly infected with fungal pathogens of the Fusarium genus, which, besides reducing yield, also taint grains with toxic metabolites. In an earlier work, we have shown that maize ears infection with single Fusarium strains was detectable through volatile sensing. In nature, infection most commonly occurs with more than a single fungal strain; hence we tested how the interactions of two strains would modulate volatile emission from infected ears. For this purpose, ears of a hybrid and a dwarf maize variety were simultaneously infected with different strains of Fusarium graminearum and F. verticillioides and, the resulting volatile profiles were compared to the ones of ears infected with single strains. Disease severity, fungal biomass, and the concentration of the oxylipin 9-hydroxy octadecadienoic acid, a signaling molecule involved in plant defense, were monitored and correlated to volatile profiles. Our results demonstrate that in simultaneous infections of hybrid and dwarf maize, the most competitive fungal strains had the largest influence on the volatile profile of infected ears. In both concurrent and single inoculations, volatile profiles reflected disease severity. Additionally, the data further indicate that dwarf maize and hybrid maize might emit common (i.e., sesquiterpenoids) and specific markers upon fungal infection. Overall this suggests that volatile profiles might be a good proxy for disease severity regardless of the fungal competition taking place in maize ears. With the appropriate sensitivity and reliability, volatile sensing thus appears as a promising tool for detecting fungal infection of maize ears under field conditions. PMID:27729923

  9. The newly-recognized species Staphylococcus massiliensis is likely to be part of the human skin microflora.

    PubMed

    Zong, Zhiyong

    2012-02-01

    Staphylococcus massiliensis is a newly-recognized species but its ecological niche and its role in infection remained unclear. Clinical isolate WCG21 recovered from a wound sample was initially identified as Staphylococcus simulans by the WalkAway automated system but was subsequently identified as S. massiliensis by partially sequencing the 16S rRNA and dnaJ genes. Strain WCG21 was probably a contaminant rather than a pathogen. The 16S rRNA gene sequences of several bacterial clones from human skin were also identical or near identical to that of S. massiliensis, suggesting that this species is part of human skin microflora. Although strain WCG21 was susceptible to a wide range of antimicrobials, it harbored a type V staphylococcal cassette chromosome mec.

  10. Polyphasic characterization of xanthomonads pathogenic to members of the Anacardiaceae and their relatedness to species of Xanthomonas.

    PubMed

    Ah-You, N; Gagnevin, L; Grimont, P A D; Brisse, S; Nesme, X; Chiroleu, F; Bui Thi Ngoc, L; Jouen, E; Lefeuvre, P; Vernière, C; Pruvost, O

    2009-02-01

    We have used amplified fragment length polymorphism (AFLP), multilocus sequence analysis (MLSA) and DNA-DNA hybridization for genotypic classification of Xanthomonas pathovars associated with the plant family Anacardiaceae. AFLP and MLSA results showed congruent phylogenetic relationships of the pathovar mangiferaeindicae (responsible for mango bacterial canker) with strains of Xanthomonas axonopodis subgroup 9.5. This subgroup includes X. axonopodis pv. citri (synonym Xanthomonas citri). Similarly, the pathovar anacardii, which causes cashew bacterial spot in Brazil, was included in X. axonopodis subgroup 9.6 (synonym Xanthomonas fuscans). Based on the thermal stability of DNA reassociation, consistent with the AFLP and MLSA data, the two pathovars share a level of similarity consistent with their being members of the same species. The recent proposal to elevate X. axonopodis pv. citri to species level as X. citri is supported by our data. Therefore, the causal agents of mango bacterial canker and cashew bacterial spot should be classified as pathovars of X. citri, namely X. citri pv. mangiferaeindicae (pathotype strain CFBP 1716) and X. citri pv. anacardii (pathotype strain CFBP 2913), respectively. Xanthomonas fuscans should be considered to be a later heterotypic synonym of Xanthomonas citri.

  11. Transcriptional analysis of the innate immune response of ducks to different species-of-origin low pathogenic H7 avian influenza viruses

    PubMed Central

    2013-01-01

    Background Wild waterfowl, including ducks, represent the classic reservoir for low pathogenicity avian influenza (LPAI) viruses and play a major role in the worldwide dissemination of AIV. AIVs belonging to the hemagglutinin (H) 7 subtype are of epidemiological and economic importance due to their potential to mutate into a highly pathogenic form of the virus. Thus far, however, relatively little work has been conducted on elucidating the host-pathogen interactions of ducks and H7 LPAIVs. In the current study, three H7 LPAIVs isolated from either chicken, duck, or turkey avian species were evaluated for their comparative effect on the transcriptional innate immune response of ducks. Results Three H7 LPAIV isolates, chicken-origin (A/chicken/Maryland/MinhMa/2004), duck-origin (A/pintail/Minnesota/423/1999), and turkey-origin (A/turkey/Virginia/SEP-67/2002) were used to infect Pekin ducks. At 3 days post-infection, RNA from spleen tissue was used for transcriptional analysis using the Avian Innate Immune Microarray (AIIM) and quantitative real-time RT-PCR (qRT-PCR). Microarray analysis revealed that a core set of 61 genes was differentially regulated in response to all three LPAIVs. Furthermore, we observed 101, 135, and 628 differentially expressed genes unique to infection with the chicken-, duck-, or turkey-origin LPAIV isolates, respectively. qRT-PCR results revealed significant (p<0.05) induction of IL-1β, IL-2, and IFNγ transcription, with the greatest induction observed upon infection with the chicken-origin isolate. Several key innate immune pathways were activated in response to LPAIV infection including the toll-like receptor and RIG-I-like receptor pathways. Conclusions Pekin ducks elicit a unique innate immune response to different species-of-origin H7 LPAIV isolates. However, twelve identifiable genes and their associated cell signaling pathways (RIG-I, NOD, TLR) are differentially expressed regardless of isolate origin. This core set of genes are

  12. Coexistence of Heavy Metal and Antibiotic Resistance within a Novel Composite Staphylococcal Cassette Chromosome in a Staphylococcus haemolyticus Isolate from Bovine Mastitis Milk

    PubMed Central

    Xue, Huping; Wu, Zhaowei; Li, Longping; Li, Fan; Wang, Yiqing

    2015-01-01

    The structure of a composite staphylococcal cassette chromosome (SCC) carried by a methicillin-resistant Staphylococcus haemolyticus (NW19A) isolated from a bovine milk sample was analyzed. The formation of the circular forms of both single SCC elements and composite SCC elements was detected in NW19A. Twenty heavy metal and antibiotic resistance-related genes coexisted in this composite SCC, suggesting that these genes might be coselected under environmental pressure. The mec gene complex in NW19A, designated type C3, is different from classic C1 or C2 gene complexes structurally and likely evolves differently. Furthermore, results from alignment of the SCC composite island of NW19A with 50 related sequences from different staphylococcal strains provided additional evidence to support the notion that coagulase-negative staphylococci (CoNS) are the original host of heavy metal resistance genes among staphylococci. Given that a SCC composite island could transfer freely among different staphylococcal species from different hosts, more attention should be paid to contamination with heavy metals and antibiotics in dairy farming environments, including wastewater, soil, feces, and feed. PMID:26169408

  13. PCR detection of staphylococcal enterotoxin genes in Staphylococcus aureus strains isolated from raw and pasteurized milk.

    PubMed

    Rall, V L M; Vieira, F P; Rall, R; Vieitis, R L; Fernandes, A; Candeias, J M G; Cardoso, K F G; Araújo, J P

    2008-12-10

    Milk is considered a nutritious food because it contains several important nutrients including proteins and vitamins. Conversely, it can be a vehicle for several pathogenic bacteria such as Staphylococcus aureus. This study aimed to analyze the frequency of genes encoding the staphylococcal enterotoxins (SEs) SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI and SEJ in S. aureus strains isolated from raw or pasteurized bovine milk. S. aureus was found in 38 (70.4%) out of 54 raw milk samples at concentrations of up to 8.9 x 10(5) CFU/ml. This microorganism was present in eight samples of pasteurized milk before the expiration date and in 11 samples analyzed on the expiration date. Of the 57 strains studied, 68.4% were positive for one or more genes encoding the enterotoxins, and 12 different genotypes were identified. The gene coding for enterotoxin A, sea, was the most frequent (16 strains, 41%), followed by sec (8 strains, 20.5%), sed (5 strains, 12.8%), seb (3 strains, 7.7%) and see (2 strains, 5.1%). Among the genes encoding the other enterotoxins, seg was the most frequently observed (11 strains, 28.2%), followed by sei (10 strains) and seh and sej (3 strains each). With the recent identification of new SEs, the perceived frequency of enterotoxigenic strains has increased, suggesting that the pathogenic potential of staphylococci may be higher than previously thought; however, further studies are required to assess the expression of these new SEs by S. aureus, and their impact in foodborne disease. The quality of Brazilian milk is still low, and efforts from the government and the entire productive chain are required to attain consumer safety.

  14. Staphylococcal protein Ecb impairs complement receptor-1 mediated recognition of opsonized bacteria

    PubMed Central

    Amdahl, Hanne; Tan, Lydia; Meri, Taru; Kuusela, Pentti I.; van Strijp, Jos A.

    2017-01-01

    Staphyloccus aureus is a major human pathogen leading frequently to sepsis and soft tissue infections with abscesses. Multiple virulence factors including several immune modulating molecules contribute to its survival in the host. When S. aureus invades the human body, one of the first line defenses is the complement system, which opsonizes the bacteria with C3b and attract neutrophils by release of chemotactic peptides. Neutrophils express Complement receptor-1 [CR1, CD35) that interacts with the C3b-opsonized particles and thereby plays an important role in pathogen recognition by phagocytic cells. In this study we observed that a fraction of S. aureus culture supernatant prevented binding of C3b to neutrophils. This fraction consisted of S. aureus leukocidins and Efb. The C-terminus of Efb is known to bind C3b and shares significant sequence homology to the extracellular complement binding protein [Ecb). Here we show that S. aureus Ecb displays various mechanisms to block bacterial recognition by neutrophils. The presence of Ecb blocked direct interaction between soluble CR1 and C3b and reduced the cofactor activity of CR1 in proteolytic inactivation of C3b. Furthermore, Ecb could dose-dependently prevent recognition of C3b by cell-bound CR1 that lead to impaired phagocytosis of NHS-opsonized S. aureus. Phagocytosis was furthermore reduced in the presence of soluble CR1 [sCR1). These data indicate that the staphylococcal protein Ecb prevents recognition of C3b opsonized bacteria by neutrophil CR1 leading to impaired killing by phagocytosis and thereby contribute to immune evasion of S. aureus. PMID:28273167

  15. Emerging Escherichia Pathogen

    PubMed Central

    Permpalung, Nitipong; Sentochnik, Deborah E.

    2013-01-01

    Escherichia hermannii was first identified as a new species in 1982. It has rarely been reported as a human pathogen. We report the first case of E. hermannii as the sole pathogen in a catheter-related bloodstream infection. PMID:23740732

  16. Autoinducer-2 of Streptococcus mitis as a Target Molecule to Inhibit Pathogenic Multi-Species Biofilm Formation In Vitro and in an Endotracheal Intubation Rat Model

    PubMed Central

    Wang, Zhengli; Xiang, Qingqing; Yang, Ting; Li, Luquan; Yang, Jingli; Li, Hongong; He, Yu; Zhang, Yunhui; Lu, Qi; Yu, Jialin

    2016-01-01

    Streptococcus mitis (S. mitis) and Pseudomonas aeruginosa (P. aeruginosa) are typically found in the upper respiratory tract of infants. We previously found that P. aeruginosa and S. mitis were two of the most common bacteria in biofilms on newborns’ endotracheal tubes (ETTs) and in their sputa and that S. mitis was able to produce autoinducer-2 (AI-2), whereas P. aeruginosa was not. Recently, we also found that exogenous AI-2 and S. mitis could influence the behaviors of P. aeruginosa. We hypothesized that S. mitis contributes to this interspecies interaction and that inhibition of AI-2 could result in inhibition of these effects. To test this hypothesis, we selected PAO1 as a representative model strain of P. aeruginosa and evaluated the effect of S. mitis as well as an AI-2 analog (D-ribose) on mono- and co-culture biofilms in both in vitro and in vivo models. In this context, S. mitis promoted PAO1 biofilm formation and pathogenicity. Dual-species (PAO1 and S. mitis) biofilms exhibited higher expression of quorum sensing genes than single-species (PAO1) biofilms did. Additionally, ETTs covered in dual-species biofilms increased the mortality rate and aggravated lung infection compared with ETTs covered in mono-species biofilms in an endotracheal intubation rat model, all of which was inhibited by D-ribose. Our results demonstrated that S. mitis AI-2 plays an important role in interspecies interactions with PAO1 and may be a target for inhibition of biofilm formation and infection in ventilator-associated pneumonia. PMID:26903968

  17. Discrimination of selected species of pathogenic bacteria using near-infrared Raman spectroscopy and principal components analysis

    NASA Astrophysics Data System (ADS)

    de Siqueira e Oliveira, Fernanda SantAna; Giana, Hector Enrique; Silveira, Landulfo

    2012-10-01

    A method, based on Raman spectroscopy, for identification of different microorganisms involved in bacterial urinary tract infections has been proposed. Spectra were collected from different bacterial colonies (Gram-negative: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterobacter cloacae, and Gram-positive: Staphylococcus aureus and Enterococcus spp.), grown on culture medium (agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from the agar surface and placed on an aluminum foil for Raman measurements. After preprocessing, spectra were submitted to a principal component analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. We found that the mean Raman spectra of different bacterial species show similar bands, and S. aureus was well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram-positive bacteria with sensitivity and specificity of 100% and Gram-negative bacteria with sensitivity ranging from 58 to 88% and specificity ranging from 87% to 99%.

  18. Discrimination of selected species of pathogenic bacteria using near-infrared Raman spectroscopy and principal components analysis

    NASA Astrophysics Data System (ADS)

    de Siqueira e Oliveira, Fernanda S.; Giana, Hector E.; Silveira, Landulfo, Jr.

    2012-03-01

    It has been proposed a method based on Raman spectroscopy for identification of different microorganisms involved in bacterial urinary tract infections. Spectra were collected from different bacterial colonies (Gram negative: E. coli, K. pneumoniae, P. mirabilis, P. aeruginosa, E. cloacae and Gram positive: S. aureus and Enterococcus sp.), grown in culture medium (Agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from Agar surface placed in an aluminum foil for Raman measurements. After pre-processing, spectra were submitted to a Principal Component Analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. It has been found that the mean Raman spectra of different bacterial species show similar bands, being the S. aureus well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram positive bacteria with sensitivity and specificity of 100% and Gram negative bacteria with good sensitivity and high specificity.

  19. Dermatitis and systemic mycosis in lined seahorses Hippocampus erectus associated with a marine-adapted Fusarium solani species complex pathogen.

    PubMed

    Salter, Caroline E; O'Donnell, Kerry; Sutton, Deanna A; Marancik, David P; Knowles, Susan; Clauss, Tonya M; Berliner, Aimee L; Camus, Alvin C

    2012-10-10

    During a 4 mo epizootic, 100% of 152 lined seahorses Hippocampus erectus in 3 separate groups died while in quarantine following shipment to a public aquarium. Twelve animals with skin depigmentation and ulceration were received by the Aquatic Pathology Service, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA, for diagnostic evaluation. Microscopically, lesions in 11 seahorses included multifocal epithelial necrosis and ulceration associated with 2 to 7 µm diameter, branching, septate fungal hyphae, typically accompanied by deeper infiltration into underlying skeletal muscle. Angioinvasion, with vascular thrombosis and tissue infarction, was a prominent feature in multiple animals. Fungal invasion of one or more internal organs was observed in 4 animals. Hyphae appeared to course freely through tissues and elicited little or no inflammatory response. Fusariosis has been reported sporadically in fish and other aquatic organisms, but identification has often been limited to the genus level based solely on morphologic features. Morphologic characteristics of the fungus isolated from this case were consistent with the Fusarium solani species complex (FSSC), which includes over 50 members that can only be identified definitively using DNA sequence data. A 3-locus typing scheme identified the isolate as a distinct species/haplotype, designated FSSC 12-a, belonging to a specific lineage that appears adapted to aquatic environments and disease in marine animals. Empirical treatment with itraconazole failed to stop mortalities, and subsequent in vitro antifungal susceptibility data explained a lack of clinical efficacy for this agent. Effective treatment in human medicine has similarly been limited by poor susceptibility to several classes of antifungal compounds.

  20. Antifungal Effect of Malaysian Aloe vera Leaf Extract on Selected Fungal Species of Pathogenic Otomycosis Species in In Vitro Culture Medium

    PubMed Central

    Saniasiaya, Jeyasakthy; Salim, Rosdan; Mohamad, Irfan; Harun, Azian

    2017-01-01

    Objectives Aloe barbadensis miller or Aloe vera has been used for therapeutic purposes since ancient times with antifungal activity known to be amongst its medicinal properties. We conducted a pilot study to determine the antifungal properties of Malaysian Aloe vera leaf extract on otomycosis species including Aspergillus niger and Candida albicans. Methods This laboratory-controlled prospective study was conducted at the Universiti Sains Malaysia. Extracts of Malaysian Aloe vera leaf was prepared in ethanol and solutions via the Soxhlet extraction method. Sabouraud dextrose agar cultured with the two fungal isolates were inoculated with the five different concentrations of each extract (50 g/mL, 25 g/mL, 12.5 g/mL, 6.25 g/mL, and 3.125 g/mL) using the well-diffusion method. Zone of inhibition was measured followed by minimum inhibitory concentration (MIC). Results For A. niger, a zone of inhibition for alcohol and aqueous extract was seen for all concentrations except 3.125 g/mL. There was no zone of inhibition for both alcohol and aqueous extracts of Aloe vera leaf for C. albicans. The MIC values of aqueous and alcohol extracts were 5.1 g/mL and 4.4 g/mL for A. niger and since no zone of inhibition was obtained for C. albicans the MIC was not determined. Conclusions The antifungal effect of alcohol extracts of Malaysian Aloe vera leaf is better than the aqueous extract for A. niger (p < 0.001). Malaysian Aloe vera has a significant antifungal effect towards A. niger. PMID:28042402

  1. A comparative, cross-species investigation of the properties and roles of transferrin- and lactoferrin-binding protein B from pathogenic bacteria.

    PubMed

    Ostan, N; Morgenthau, A; Yu, R H; Gray-Owen, S D; Schryvers, A B

    2017-02-01

    Pathogenic bacteria from the families Neisseriaeceae and Moraxellaceae acquire iron from their host using surface receptors that have the ability to hijack iron from the iron-sequestering host proteins transferrin (Tf) and lactoferrin (Lf). The process of acquiring iron from Tf has been well-characterized, including the role of the surface lipoprotein transferrin-binding protein B (TbpB). In contrast, the only well-defined role for the homologue, LbpB, is in its protection against cationic antimicrobial peptides, which is mediated by regions present in some LbpBs that are highly enriched in glutamic or aspartic acid. In this study we compare the Tf-TbpB and the Lf-LbpB interactions and examine the protective effect of LbpB against extracts from human and transgenic mouse neutrophils to gains insights into the physiological roles of LbpB. The results indicate that in contrast to the Tf-TbpB interaction, Lf-LbpB interaction is sensitive to pH and varies between species. In addition, the results with transgenic mouse neutrophils raise the question of whether there is species specificity in the cleavage of Lf to generate cationic antimicrobial peptides or differences in the potency of peptides derived from mouse and human Lf.

  2. Amoebae as a tool to isolate new bacterial species, to discover new virulence factors and to study the host-pathogen interactions.

    PubMed

    Tosetti, Nicolo; Croxatto, Antony; Greub, Gilbert

    2014-12-01

    Amoebae are unicellular protozoan present worldwide in several environments mainly feeding on bacteria. Some of them, the amoebae-resistant bacteria (ARBs), have evolved mechanisms to survive and replicate inside amoebal species. These mainly include legionella, mycobacteria and Chlamydia-related bacteria. Amoebae can provide a replicative niche, can act as reservoir for bacteria whereas the cystic form can protect the internalized bacteria. Moreover, the amoebae represent a Trojan horse for ARBs to infect animals. The long interaction between amoebae and bacteria has likely selected for bacterial virulence traits leading to the adaptation towards an intracellular lifestyle, and some ARBs have acquired the ability to infect mammals. This review intends to highlight the important uses of amoebae in several fields in microbiology by describing the main tools developed using amoebal cells. First, amoebae such as Acanthamoeba are used to isolate and discover new intracellular bacterial species by two main techniques: the amoebal co-culture and the amoebal enrichment. In the second part, taking Waddlia chondrophila as example, we summarize some important recent applications of amoebae to discover new bacterial virulence factors, in particular thanks to the amoebal plaque assay. Finally, the genetically tractable Dictyostelium discoideum is used as a model organism to study host-pathogen interactions, in particular with the development of several approaches to manipulate its genome that allowed the creation of a wide range of mutated strains largely shared within the Dictyostelium community.

  3. Biodegradation of Selected Nigerian Fruit Peels by the use of a Non-pathogenic Rhizobium species CWP G34B.

    PubMed

    Esther Boboye, Bolatito; Ajayi, George Olarewaju

    2012-01-01

    This study was carried out to determine the ability of Rhizobium species CWP G34B to degrade the peels of selected Nigerian fruits. The potential of the bacterium to digest some carbon sources (lactose, maltose, sucrose and mannitol) and peels of some Nigerian fruits (pineapple, orange, plantain, banana, pawpaw and mango fruits) was investigated by growing the organism on the substances separately after which DNSA reagent method was used to quantify glucose released into the medium. The results showed that the bacterium was able to degrade all the carbohydrates with the highest and the lowest glucose concentrations of 5.52 mg/ml for lactose and 0.50 mg/ml for mannitol. The carbohydrate-catabolic-enzyme (CCE) activity ranged from 0.169 mg/ml to 1.346 mg/ml glucose per mg/ml protein. Mannitol exhibited the highest CCE activity while the lowest activity was observed in the presence of sucrose. The amount of extracellular protein synthesized was highest (9.803 mg/ml) in the presence of maltose and lowest (0.925 mg/ml) in mannitol. The mean polygalacturonase activity was 0.54 unit/ml when the bacterium was grown in pectin in contrast to 0.28 unit/ml when it was grown in mannitol. The bacterium showed ability to breakdown the peels of the Nigerian fruits with the highest capability in banana and pineapple (0.42 and 0.41 mg/ml glucose per mg/ml protein respectively). The fruit-peel-degrading enzyme activity was lowest in orange peel (0.75 unit/ml).

  4. Prevalence and Genotype Allocation of Pathogenic Leptospira Species in Small Mammals from Various Habitat Types in Germany

    PubMed Central

    Karnath, Carolin; Silaghi, Cornelia; Schex, Susanne; Eßbauer, Sandra; Pfeffer, Martin

    2016-01-01

    Small mammals serve as most important reservoirs for Leptospira spp., the causative agents of Leptospirosis, which is one of the most neglected and widespread zoonotic diseases worldwide. The knowledge about Leptospira spp. occurring in small mammals from Germany is scarce. Thus, this study’s objectives were to investigate the occurrence of Leptospira spp. and the inherent sequence types in small mammals from three different study sites: a forest in southern Germany (site B1); a National Park in south-eastern Germany (site B2) and a renaturalised area, in eastern Germany (site S) where small mammals were captured. DNA was extracted from kidneys of small mammals and tested for Leptospira spp. by real-time PCR. Positive samples were further analysed by duplex and conventional PCRs. For 14 positive samples, multi locus sequence typing (MLST) was performed. Altogether, 1213 small mammals were captured: 216 at site B1, 456 at site B2 and 541 at site S belonging to following species: Sorex (S.) araneus, S. coronatus, Apodemus (A.) flavicollis, Myodes glareolus, Microtus (Mi.) arvalis, Crocidura russula, Arvicola terrestris, A. agrarius, Mustela nivalis, Talpa europaea, and Mi. agrestis. DNA of Leptospira spp. was detected in 6% of all small mammals. At site B1, 25 small mammals (11.6%), at site B2, 15 small mammals (3.3%) and at site S, 33 small mammals (6.1%) were positive for Leptospira spp. Overall, 54 of the positive samples were further determined as L. kirschneri, nine as L. interrogans and four as L. borgpetersenii while five real-time PCR-positive samples could not be further determined by conventional PCR. MLST results revealed focal occurrence of L. interrogans and L. kirschneri sequence type (ST) 117 while L. kirschneri ST 110 was present in small mammals at all three sites. Further, this study provides evidence for a particular host association of L. borgpetersenii to mice of the genus Apodemus. PMID:27015596

  5. Assessing the intra-species genetic variability in the clonal pathogen Campylobacter fetus: CRISPRs are highly polymorphic DNA markers.

    PubMed

    Calleros, Lucía; Betancor, Laura; Iraola, Gregorio; Méndez, Alejandra; Morsella, Claudia; Paolicchi, Fernando; Silveyra, Silvia; Velilla, Alejandra; Pérez, Ruben

    2017-01-01

    Campylobacter fetus is a Gram-negative, microaerophilic bacterium that infects animals and humans. The subspecies Campylobacter fetus subsp. fetus (Cff) affects a broad range of vertebrate hosts and induces abortion in cows and sheep. Campylobacter fetus subsp. venerealis (Cfv) is restricted to cattle and causes the endemic disease bovine genital campylobacteriosis, which triggers reproductive problems and is responsible for major economic losses. Campylobacter fetus subsp. testudinum (Cft) has been isolated mostly from apparently healthy reptiles belonging to different species but also from ill snakes and humans. Genotypic differentiation of Cff and Cfv is difficult, and epidemiological information is scarce because there are few methods to study the genetic diversity of the strains. We analyze the efficacy of MLST, ribosomal sequences (23S gene and internal spacer region), and CRISPRs to assess the genetic variability of C. fetus in bovine and human isolates. Sequences retrieved from complete genomes were included in the analysis for comparative purposes. MLST and ribosomal sequences had scarce or null variability, while the CRISPR-cas system structure and the sequence of CRISPR1 locus showed remarkable diversity. None of the sequences here analyzed provided evidence of a genetic differentiation of Cff and Cfv in bovine isolates. Comparison of bovine and human isolates with Cft strains showed a striking divergence. Inter-host differences raise the possibility of determining the original host of human infections using CRISPR sequences. CRISPRs are the most variable sequences analyzed in C. fetus so far, and constitute excellent representatives of a dynamic fraction of the genome. CRISPR typing is a promising tool to characterize isolates and to track the source and transmission route of C. fetus infections.

  6. Prevalence and Genotype Allocation of Pathogenic Leptospira Species in Small Mammals from Various Habitat Types in Germany.

    PubMed

    Obiegala, Anna; Woll, Dietlinde; Karnath, Carolin; Silaghi, Cornelia; Schex, Susanne; Eßbauer, Sandra; Pfeffer, Martin

    2016-03-01

    Small mammals serve as most important reservoirs for Leptospira spp., the causative agents of Leptospirosis, which is one of the most neglected and widespread zoonotic diseases worldwide. The knowledge about Leptospira spp. occurring in small mammals from Germany is scarce. Thus, this study's objectives were to investigate the occurrence of Leptospira spp. and the inherent sequence types in small mammals from three different study sites: a forest in southern Germany (site B1); a National Park in south-eastern Germany (site B2) and a renaturalised area, in eastern Germany (site S) where small mammals were captured. DNA was extracted from kidneys of small mammals and tested for Leptospira spp. by real-time PCR. Positive samples were further analysed by duplex and conventional PCRs. For 14 positive samples, multi locus sequence typing (MLST) was performed. Altogether, 1213 small mammals were captured: 216 at site B1, 456 at site B2 and 541 at site S belonging to following species: Sorex (S.) araneus, S. coronatus, Apodemus (A.) flavicollis, Myodes glareolus, Microtus (Mi.) arvalis, Crocidura russula, Arvicola terrestris, A. agrarius, Mustela nivalis, Talpa europaea, and Mi. agrestis. DNA of Leptospira spp. was detected in 6% of all small mammals. At site B1, 25 small mammals (11.6%), at site B2, 15 small mammals (3.3%) and at site S, 33 small mammals (6.1%) were positive for Leptospira spp. Overall, 54 of the positive samples were further determined as L. kirschneri, nine as L. interrogans and four as L. borgpetersenii while five real-time PCR-positive samples could not be further determined by conventional PCR. MLST results revealed focal occurrence of L. interrogans and L. kirschneri sequence type (ST) 117 while L. kirschneri ST 110 was present in small mammals at all three sites. Further, this study provides evidence for a particular host association of L. borgpetersenii to mice of the genus Apodemus.

  7. Effect of preservation techniques and food additives on staphylococcal thermonuclease.

    PubMed

    Kumar, J K; Sharma, A K; Kulkarni, P R

    2000-08-01

    Staphylococcal TNase was found to retain its activity fully even after exposure to chilling and refrigeration temperatures for 24 h. It was not inhibited by p-hydroxy benzoic acid, sorbic acid, methylpropyl p-benzoic acid and sodium nitrite in the concentration range of 0.04 to 0.5%, whereas it was inhibited by 100 ppm of butylated hydroxy anisole (BHA), 200 ppm of butylated hydroxy toluene (BHT), and 300 ppm of propyl gallate. There was not complete inhibition of S. aureus and TNase by tocopherol (TP) and ascorbic acid (AA) even at concentration of 300 ppm. These results indicate that TNase can be used as an index of potentially enterotoxin producing S. aureus contamination in foods subjected to chilling, refrigeration as well as in foods containing common preservatives and antioxidants.

  8. Detecting staphylococcal enterotoxin B using an automated fiber optic biosensor.

    PubMed

    King, K D; Anderson, G P; Bullock, K E; Regina, M J; Saaski, E W; Ligler, F S

    1999-02-01

    The Man-portable Analyte Identification System (MANTIS), the first fully automated, self-contained, portable fiber optic biosensor, was utilized for the detection of Staphylococcal Enterotoxin B (SEB), a bacterial toxin produced by Staphylococcus aureus that commonly causes food poisoning. Because of its remarkable toxicity and stability, SEB is considered a prime threat as a biological weapon of mass destruction. The assay for SEB was used to evaluate the MANTIS' ability to function in the presence of various environmental interferents. The sensor could reliably detect SEB spiked into liquid samples containing a variety of smoke particles. However, substantial interference occurred when SEB was mixed into matrices capable of adsorbing SEB, such as 1% solutions of clay, topsoil, or pollen. Of equal importance, none of the interferents produced false positives in the MANTIS. The MANTIS demonstrated the capability to perform simultaneous immunoassays rapidly in the field with little or no user intervention.

  9. Effects of staphylococcal enterotoxin A on the rat gastrointestinal tract.

    PubMed Central

    Beery, J T; Taylor, S L; Schlunz, L R; Freed, R C; Bergdoll, M S

    1984-01-01

    Staphylococcal enterotoxin A (SEA) was administered orally (15 micrograms) to two groups of rats. A marked immune reaction was evoked in the stomach and proximal small intestine of the first group. The second group of rats was used to study the absorptive fate and sites of action of orally administered SEA, utilizing immunoperoxidase staining. After oral dosing of the second group of rats. SEA-related immunoperoxidase staining was confined to: (i) neutrophils and macrophages, principally in the duodenum, and (ii) glomerular neutrophils and cells of the proximal convoluted tubules. Peroxidase staining of the kidney was noted within 15 min of exposure, indicating that SEA or some major postabsorption antigenic product can promptly pass through an intact gastrointestinal mucous membrane and become renally localized. Intestinal and renal detoxification and removal was indicated by an absence of detectable antigen in rats 180 min postexposure. Neuronal binding of SEA in the gastrointestinal tract was not demonstrable. Images PMID:6370862

  10. Mutations defining functional regions of the superantigen staphylococcal enterotoxin B

    PubMed Central

    1992-01-01

    Staphylococcal enterotoxin B (SEB) is both a superantigen and toxin. As a superantigen, SEB can bind to major histocompatibility complex (MHC) class II molecules to form a ligand for alpha/beta T cell receptors bearing particular V beta elements. As a toxin, SEB causes rapid weight loss in mice sometimes leading to death. We show here that both of these functions map to the NH2-terminal portion of the toxin. Three regions were identified: one important in MHC class II binding, one in T cell recognition, and one in both functions. These results support the conclusion that the toxicity of SEB is related to massive T cell stimulation and release of cytokine mediators and show that the residues interacting with MHC and the T cell receptor are intertwined. PMID:1370682

  11. NMR analysis of staphylococcal nuclease thermal quench refolding kinetics.

    PubMed

    Kautz, R A; Fox, R O

    1993-05-01

    Thermally unfolded staphylococcal nuclease has been rapidly quenched to temperatures near 0 degree C and the refolding behavior examined using an NMR kinetic experiment. Unfolded protein, exhibiting random coil chemical shifts, persists following the quench and refolds in two distinct kinetic phases. A protein folding intermediate with a trans Lys 116-Pro 117 peptide bond is transiently overpopulated and relaxes to the predominantly cis native cis-trans equilibrium. The rate of trans-->cis isomerization in the native-like nuclease intermediate is approximately 100-fold faster than that observed in a Lys-Pro model peptide. The activation enthalpy of 20 kcal/mol observed for the nuclease Lys 116-Pro 117 peptide bond is comparable to that observed for other X-Pro isomerizations.

  12. An outbreak of staphylococcal skin infections among river rafting guides.

    PubMed

    Decker, M D; Lybarger, J A; Vaughn, W K; Hutcheson, R H; Schaffner, W

    1986-12-01

    Outbreaks of staphylococcal skin infections among healthy adults are most unusual. The authors report an epidemic of skin infections due to Staphylococcus aureus that involved river rafting guides in Tennessee, South Carolina, and North Carolina in summer 1982. Infections occurred only among employees of the rafting companies that provided communal, on-site housing; carriage rates of S. aureus were as high as 89% at those companies. A case-control study found that having had an infected roommate was significantly associated with infection, as was working at the livery with the most crowded housing. This outbreak appeared to be due to two factors: frequent minor skin wounds acquired while rafting, and prolonged close contact among the persons with wounds. It is likely that crowding and exposure to infected wounds led to elevated S. aureus carriage rates, which in turn increased the probability that wounds would become infected. Repeated immersion in water likely enhanced the development of infections.

  13. The Production of Reactive Oxygen Species Is a Universal Action Mechanism of Amphotericin B against Pathogenic Yeasts and Contributes to the Fungicidal Effect of This Drug

    PubMed Central

    Mesa-Arango, Ana Cecilia; Trevijano-Contador, Nuria; Román, Elvira; Sánchez-Fresneda, Ruth; Casas, Celia; Herrero, Enrique; Argüelles, Juan Carlos; Pla, Jesús; Cuenca-Estrella, Manuel

    2014-01-01

    Amphotericin B (AMB) is an antifungal drug that binds to ergosterol and forms pores at the cell membrane, causing the loss of ions. In addition, AMB induces the accumulation of reactive oxygen species (ROS), and although these molecules have multiple deleterious effects on fungal cells, their specific role in the action mechanism of AMB remains unknown. In this work, we studied the role of ROS in the action mechanism of AMB. We determined the intracellular induction of ROS in 44 isolates of different pathogenic yeast species (Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida krusei, Cryptococcus neoformans, and Cryptococcus gattii). We also characterized the production of ROS in AMB-resistant isolates. We found that AMB induces the formation of ROS in all the species tested. The inhibition of the mitochondrial respiratory chain by rotenone blocked the induction of ROS by AMB and provided protection from the killing action of the antifungal. Moreover, this phenomenon was absent in strains that displayed resistance to AMB. These strains showed an alteration in the respiration rate and mitochondrial membrane potential and also had higher catalase activity than that of the AMB-susceptible strains. Consistently, AMB failed to induce protein carbonylation in the resistant strains. Our data demonstrate that the production of ROS by AMB is a universal and important action mechanism that is correlated with the fungicidal effect and might explain the low rate of resistance to the molecule. Finally, these data provide an opportunity to design new strategies to improve the efficacy of this antifungal. PMID:25155595

  14. Detection and identification of pathogenic trypanosome species in tsetse flies along the Comoé River in Côte d’Ivoire

    PubMed Central

    Djohan, Vincent; Kaba, Dramane; Rayaissé, Jean-Baptiste; Dayo, Guiguigbaza-Kossigan; Coulibaly, Bamoro; Salou, Ernest; Dofini, Fabien; Kouadio, Alain De Marie Koffi; Menan, Hervé; Solano, Philippe

    2015-01-01

    In order to identify pathogenic trypanosomes responsible for African trypanosomiasis, and to better understand tsetse-trypanosome relationships, surveys were undertaken in three sites located in different eco-climatic areas in Côte d’Ivoire during the dry and rainy seasons. Tsetse flies were caught during five consecutive days using biconical traps, dissected and microscopically examined looking for trypanosome infection. Samples from infected flies were tested by PCR using specific primers for Trypanosoma brucei s.l., T. congolense savannah type, T. congolense forest type and T. vivax. Of 1941 tsetse flies caught including four species, i.e. Glossina palpalis palpalis, G. p. gambiensis, G. tachinoides and G. medicorum, 513 (26%) were dissected and 60 (12%) were found positive by microscopy. Up to 41% of the infections were due to T. congolense savannah type, 30% to T. vivax, 20% to T. congolense forest type and 9% due to T. brucei s.l. All four trypanosome species and subgroups were identified from G. tachinoides and G. p. palpalis, while only two were isolated from G. p. gambiensis (T. brucei s.l., T. congolense savannah type) and G. medicorum (T. congolense forest, savannah types). Mixed infections were found in 25% of cases and all involved T. congolense savannah type with another trypanosome species. The simultaneous occurrence of T. brucei s.l., and tsetse from the palpalis group may suggest that human trypanosomiasis can still be a constraint in these localities, while high rates of T. congolense and T. vivax in the area suggest a potential risk of animal trypanosomiasis in livestock along the Comoé River. PMID:26035296

  15. Analysis of the complete genome sequence of Nocardia seriolae UTF1, the causative agent of fish nocardiosis: The first reference genome sequence of the fish pathogenic Nocardia species

    PubMed Central

    Yasuike, Motoshige; Nishiki, Issei; Iwasaki, Yuki; Nakamura, Yoji; Fujiwara, Atushi; Shimahara, Yoshiko; Kamaishi, Takashi; Yoshida, Terutoyo; Nagai, Satoshi; Kobayashi, Takanori; Katoh, Masaya

    2017-01-01

    Nocardiosis caused by Nocardia seriolae is one of the major threats in the aquaculture of Seriola species (yellowtail; S. quinqueradiata, amberjack; S. dumerili and kingfish; S. lalandi) in Japan. Here, we report the complete nucleotide genome sequence of N. seriolae UTF1, isolated from a cultured yellowtail. The genome is a circular chromosome of 8,121,733 bp with a G+C content of 68.1% that encodes 7,697 predicted proteins. In the N. seriolae UTF1 predicted genes, we found orthologs of virulence factors of pathogenic mycobacteria and human clinical Nocardia isolates involved in host cell invasion, modulation of phagocyte function and survival inside the macrophages. The virulence factor candidates provide an essential basis for understanding their pathogenic mechanisms at the molecular level by the fish nocardiosis research community in future studies. We also found many potential antibiotic resistance genes on the N. seriolae UTF1 chromosome. Comparative analysis with the four existing complete genomes, N. farcinica IFM 10152, N. brasiliensis HUJEG-1 and N. cyriacigeorgica GUH-2 and N. nova SH22a, revealed that 2,745 orthologous genes were present in all five Nocardia genomes (core genes) and 1,982 genes were unique to N. seriolae UTF1. In particular, the N. seriolae UTF1 genome contains a greater number of mobile elements and genes of unknown function that comprise the differences in structure and gene content from the other Nocardia genomes. In addition, a lot of the N. seriolae UTF1-specific genes were assigned to the ABC transport system. Because of limited resources in ocean environments, these N. seriolae UTF1 specific ABC transporters might facilitate adaptation strategies essential for marine environment survival. Thus, the availability of the complete N. seriolae UTF1 genome sequence will provide a valuable resource for comparative genomic studies of N. seriolae isolates, as well as provide new insights into the ecological and functional diversity of

  16. Highly virulent Beauveria bassiana strains against the two-spotted spider mite, Tetranychus urticae, show no pathogenicity against five phytoseiid mite species.

    PubMed

    Wu, Shengyong; Xie, Haicui; Li, Maoye; Xu, Xuenong; Lei, Zhongren

    2016-12-01

    Entomopathogenic fungi and predatory mites can independently contribute to suppressing the two-spotted spider mite, Tetranychus urticae Koch. It is important to assess the risk of possible fungal infections in predators when a combination of them are being considered as a tandem control strategy for suppressing T. urticae. The first part of this study tested 12 Beauveria bassiana isolates for virulence in T. urticae. Strains SCWJ-2, SDDZ-9, LNSZ-26, GZGY-1-3 and WLMQ-32 were found to be the most potent, causing 37.6-49.5% adult corrected mortality at a concentration of 1 × 10(7) m/L conidia 4 days post-treatment. The second part evaluated the pathogenicity of these five strains in five species of predatory phytoseiid mites. The bioassay results indicated that all adult predatory mite mortalities ranged from 7.5 to 9.1% 4 days post-treatment. No viable fungal hyphae were found on predator cadavers. Observations with scanning electron microscopy revealed that conidia were attached to the cuticle of predatory mites within 2-12 h after spraying with strain LNSZ-26, and had germinated within 24-36 h. After 48 h, conidia had gradually been shed from the mites, after none of the conidia had penetrated the cuticular surfaces. In contrast, the germinated conidia successfully penetrated the cuticle of T. urticae, and within 60 h the fungus colonized the mite's body. Our study demonstrated that although several B. bassiana strains displayed a high virulence in T. urticae there was no evident pathogenicity to phytoseiid mites. These findings support the potential use of entomopathogenic fungus in combination with predatory mites in T. urticae control programs.

  17. Prevalence and Antibiotic Resistance of Gram-Negative Pathogenic Bacteria Species Isolated from Periplaneta americana and Blattella germanica in Varanasi, India

    PubMed Central

    Wannigama, D Leshan; Dwivedi, Rishabh; Zahraei-Ramazani, Alireza

    2014-01-01

    Background Cockroaches are among the medically important pests found within the human habitations that cause serious public health problems. They may harbor a number of pathogenic bacteria on the external surface with antibiotic resistance. Hence, they are regarded as major microbial vectors. This study investigates the prevalence and antibiotic resistance of Gram-negative pathogenic bacteria species isolated from Periplaneta americana and Blattella germanica in Varanasi, India. Methods: Totally, 203 adult cockroaches were collected form 44 households and 52 food-handling establishments by trapping. Bacteriological examination of external surfaces of Pe. americana and Bl. germanica were carried out using standard method and antibiotics susceptibility profiles of the isolates were determined using Kirby-Bauer disc diffusion methods. Results: Among the places, we found that 54% had cockroache infestation in households and 77% in food- handling establishments. There was no significant different between the overall bacteria load of the external surface in Pe. americana (64.04%) and Bl. germanica (35.96%). However the predominant bacteria on cockroaches were Klebsiella pneumonia, Escherichia coli, Enterobacter aerogenes, and Pseudomonas aeruginosa. However, Kl. pneumoniae and Ps. aeruginosa were the most prevalent, drug-resistant strains were isolated from the cockroaches with 100% resistance to sulfamethoxazole/trimethoprim and ampicillin. For individual strains of bacteria, Escherichia coli was found to have multi-resistance to four antibiotic tested, Citrobacter freundii four, Enterobacter aerogenes and Proteus mirabilis to three. Conclusion: Cockroaches are uniformly distributed in domestic environment, which can be a possible vector for transmission of drug-resistant bacteria and food-borne diseases. PMID:25629061

  18. Recurring staphylococcal scalded skin syndrome in a very low birth weight infant: a case report

    PubMed Central

    2009-01-01

    Introduction Staphylococcal scalded skin syndrome is an extensive desquamative erythematous condition caused by exfoliative toxins of Staphylococcus aureus. This disease usually affects neonates and generally responds rapidly to antibiotic therapy. Case presentation We describe the case of a premature baby boy, weighing 1030 g, born after 26 6/7 weeks gestation, who developed two episodes of Staphylococcal scalded skin syndrome on days 19 and 48 of life. Cultures obtained during the first period did not reveal Staphylococcus aureus, but diagnosis was based on typical clinical grounds. Although the initial diagnosis was irritation by the fixation material of a nasal continuous positive airway pressure tube, the infant showed rapidly progressing skin blistering and exfoliation, characteristic of Staphylococcal scalded skin syndrome. After administration of antibiotic treatment, complete recovery was seen. In the second period, diagnosis of Staphylococcal scalded skin syndrome was made clinically and confirmed by results of microbiologic investigations. Staphylococcus aureus was cultured from the nose, skin lesions and the pharynx. The strain appeared to produce exfoliative toxin A. The clinical response to similar antibiotic treatment was identical to the first period of Staphylococcal scalded skin syndrome. Conclusion This case report discusses an unusual presentation of recurring Staphylococcal scalded skin syndrome in a baby with a very low birth weight. PMID:19830179

  19. Multiple-Strain Approach and Probabilistic Modeling of Consumer Habits in Quantitative Microbial Risk Assessment: A Quantitative Assessment of Exposure to Staphylococcal Enterotoxin A in Raw Milk.

    PubMed

    Crotta, Matteo; Rizzi, Rita; Varisco, Giorgio; Daminelli, Paolo; Cunico, Elena Cosciani; Luini, Mario; Graber, Hans Ulrich; Paterlini, Franco; Guitian, Javier

    2016-03-01

    Quantitative microbial risk assessment (QMRA) models are extensively applied to inform management of a broad range of food safety risks. Inevitably, QMRA modeling involves an element of simplification of the biological process of interest. Two features that are frequently simplified or disregarded are the pathogenicity of multiple strains of a single pathogen and consumer behavior at the household level. In this study, we developed a QMRA model with a multiple-strain approach and a consumer phase module (CPM) based on uncertainty distributions fitted from field data. We modeled exposure to staphylococcal enterotoxin A in raw milk in Lombardy; a specific enterotoxin production module was thus included. The model is adaptable and could be used to assess the risk related to other pathogens in raw milk as well as other staphylococcal enterotoxins. The multiplestrain approach, implemented as a multinomial process, allowed the inclusion of variability and uncertainty with regard to pathogenicity at the bacterial level. Data from 301 questionnaires submitted to raw milk consumers were used to obtain uncertainty distributions for the CPM. The distributions were modeled to be easily updatable with further data or evidence. The sources of uncertainty due to the multiple-strain approach and the CPM were identified, and their impact on the output was assessed by comparing specific scenarios to the baseline. When the distributions reflecting the uncertainty in consumer behavior were fixed to the 95th percentile, the risk of exposure increased up to 160 times. This reflects the importance of taking into consideration the diversity of consumers' habits at the household level and the impact that the lack of knowledge about variables in the CPM can have on the final QMRA estimates. The multiple-strain approach lends itself to use in other food matrices besides raw milk and allows the model to better capture the complexity of the real world and to be capable of geographical

  20. Binding and activation of major histocompatibility complex class II-deficient macrophages by staphylococcal exotoxins

    NASA Technical Reports Server (NTRS)

    Beharka, A. A.; Armstrong, J. W.; Iandolo, J. J.; Chapes, S. K.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    Macrophages from C2D transgenic mice deficient in the expression of major histocompatibility complex (MHC) class II proteins were used to identify binding sites for superantigens distinct from the MHC class II molecule. Iodinated staphylococcal enterotoxins A and B (SEA and SEB) and exfoliative toxins A and B (ETA and ETB) bound to C2D macrophages in a concentration-dependent and competitive manner. All four toxins increased F-actin concentration within 30 s of their addition to C2D macrophages, indicating that signal transduction occurred in response to toxin in the absence of class II MHC. Furthermore, ETA, ETB, SEA, and, to a lesser extent, SEB induced C2D macrophages to produce interleukin 6. Several molecular species on C2D macrophages with molecular masses of 140, 97, 61, 52, 43, and 37 kDa bound SEA in immunoprecipitation experiments. These data indicate the presence of novel, functionally active toxin binding sites on murine macrophages distinct from MHC class II molecules.

  1. In vitro synergistic effect of the CM11 antimicrobial peptide in combination with common antibiotics against clinical isolates of six species of multidrug-resistant pathogenic bacteria.

    PubMed

    Amani, Jafar; Barjini, Kamal A; Moghaddam, Mehrdad M; Asadi, Asadollah

    2015-01-01

    During the last decades, increase of antibiotic resistance among pathogenic bacteria has been considered as a global concern. Therefore, it is important to find new antimicrobial agents and/or therapeutic strategies. In previous studies we investigated antibacterial activity of the CM11 peptide against multiple drug resistant clinical isolates of six bacteria species including Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Salmonella typhimurium. In this study, in order to reduce treatment costs and the cytotoxic effect of CM11 peptide, was analyzed its synergic interaction with selected antibiotics. In this reason, specific antibiotics for each bacterium were selected considering the guidelines of the "Clinical and Laboratory Standards Institute". Based on the results , using a checkerboard procedure through the broth microdilution method, MICs of antibiotic agents alone and in combination with the peptide were determined. In most cases, synergistic effects between CM11 peptide and selected antibiotics against six bacteria species were observed as partial synergy. However, for S. aureus and P. aeruginosaa synergic interaction between peptide and selective antibiotics was observed with penicillin and ceftazidime, respectively. For K. pneumoniae, synergic effect was observed when CM11 peptide was used in combination with norfloxacin and also the combination of peptide with norfloxacin showed synergic effect against A. baumannii. Combination between the CM11 peptide and ciprofloxacin showed synergic effect on E. coli while only partial synergy was observed for S. typhimurium in combination with cefotaxime and ceftazidime. These results suggest that when selected antibiotic used in combination with the CM11 peptide, the dose of some antibiotics, especially the dose independent antibiotics, may be reduced for eliminating drug resistant bacteria.

  2. The glutathione peroxidase-mediated reactive oxygen species resistance, fungicide sensitivity and cell wall construction in the citrus fungal pathogen Alternaria alternata.

    PubMed

    Yang, Siwy Ling; Yu, Pei-Ling; Chung, Kuang-Ren

    2016-03-01

    The ability to detoxify reactive oxygen species (ROS) is critical for pathogenicity in the necrotrophic fungus Alternaria alternata. We report a glutathione peroxidase 3 (AaGPx3) involved in the complex signalling network that is essential for the detoxification of cellular stresses induced by ROS and for A. alternata pathogenesis in citrus. AaGPx3 deletion mutants displayed increased sensitivity to H2 O2 and many ROS-generating compounds. AaGPx3 is required for correct fungal development as the AaGPx3 mutant strains showed a severe reduction in conidiation. AaGPx3 mutants accumulated higher chitin content than the wild-type and were less sensitive to the cell wall-targeting compounds calcofluor white and Congo red, as well as the fungicides fludioxonil and vinclozolin, suggesting a role of the glutathione systems in fungal cell wall construction. Virulence assays revealed that AaGPx3 is required for full virulence. The expression of AaGPx3 was downregulated in fungal strains carrying defective NADPH oxidase (Nox) or the oxidative stress responsive regulators YAP1 and HOG1, all implicated in ROS resistance. These results further support the important role of ROS detoxification during A. alternata pathogenesis in citrus. Overall, our study provides genetic evidence to define the central role of AaGPx3 in the biological and pathological functions of A. alternata.

  3. Pathogenic molds (including Aspergillus species) in hospital water distribution systems: a 3-year prospective study and clinical implications for patients with hematologic malignancies.

    PubMed

    Anaissie, Elias J; Stratton, Shawna L; Dignani, M Cecilia; Lee, Choon-kee; Summerbell, Richard C; Rex, John H; Monson, Thomas P; Walsh, Thomas J

    2003-04-01

    The incidence of mold infections in patients with hematologic malignancies continues to increase despite the widespread use of air filtration systems, suggesting the presence of other hospital sources for these molds. Water sources are known to harbor pathogenic molds. We examined samples from water, water surfaces, air, and other environment sources from a bone marrow transplantation unit with optimal air precautions. Molds (Aspergillus species, others) were recovered in 70% of 398 water samples, in 22% of 1311 swabs from plumbing structures and environmental surfaces, and in 83% of 274 indoor air samples. Microscopic examination of the water plumbing lines revealed hyphal forms compatible with molds. Four findings suggest that indoor airborne molds were aerosolized from the water: (1) higher mean airborne concentrations of molds in bathrooms (16.1 colony-forming units [CFU]/m(3)) than in patient rooms (7 CFU/m(3)) and hallways (8.6 CFU/m(3); P =.00005); (2) a strong type and rank correlation between molds isolated from hospital water and those recovered from indoor hospital; (3) lack of seasonal correlation between the airborne mold concentration in outdoor and indoor air; and (4) molecular relatedness between a clinical strain and a water-related strain (previously reported). Hospital water distribution systems may serve as a potential indoor reservoir of Aspergillus and other molds leading to aerosolization of fungal spores and potential exposure for patients.

  4. Lack of the COMPASS Component Ccl1 Reduces H3K4 Trimethylation Levels and Affects Transcription of Secondary Metabolite Genes in Two Plant–Pathogenic Fusarium Species

    PubMed Central

    Studt, Lena; Janevska, Slavica; Arndt, Birgit; Boedi, Stefan; Sulyok, Michael; Humpf, Hans-Ulrich; Tudzynski, Bettina; Strauss, Joseph

    2017-01-01

    In the two fungal pathogens Fusarium fujikuroi and Fusarium graminearum, secondary metabolites (SMs) are fitness and virulence factors and there is compelling evidence that the coordination of SM gene expression is under epigenetic control. Here, we characterized Ccl1, a subunit of the COMPASS complex responsible for methylating lysine 4 of histone H3 (H3K4me). We show that Ccl1 is not essential for viability but a regulator of genome-wide trimethylation of H3K4 (H3K4me3). Although, recent work in Fusarium and Aspergillus spp. detected only sporadic H3K4 methylation at the majority of the SM gene clusters, we show here that SM profiles in CCL1 deletion mutants are strongly deviating from the wild type. Cross-complementation experiments indicate high functional conservation of Ccl1 as phenotypes of the respective △ccl1 were rescued in both fungi. Strikingly, biosynthesis of the species-specific virulence factors gibberellic acid and deoxynivalenol produced by F. fujikuroi and F. graminearum, respectively, was reduced in axenic cultures but virulence was not attenuated in these mutants, a phenotype which goes in line with restored virulence factor production levels in planta. This suggests that yet unknown plant-derived signals are able to compensate for Ccl1 function during pathogenesis. PMID:28119673

  5. Immunogenicity and efficacy against lethal aerosol staphylococcal enterotoxin B challenge in monkeys by intramuscular and respiratory delivery of proteosome-toxoid vaccines.

    PubMed Central

    Lowell, G H; Colleton, C; Frost, D; Kaminski, R W; Hughes, M; Hatch, J; Hooper, C; Estep, J; Pitt, L; Topper, M; Hunt, R E; Baker, W; Baze, W B

    1996-01-01

    Staphylococcal enterotoxin B (SEB), a primary cause of food poisoning, is also a superantigen that can cause toxic shock after traumatic or surgical staphylococcal wound [correction of would] infections or viral influenza-associated staphylococcal superinfections or when aerosolized for use as a potential biologic warfare threat agent. Intranasal or intramuscular (i.m.) immunization with formalinized SEB toxoid formulated with meningococcal outer membrane protein proteosomes has previously been shown to be immunogenic and protective against lethal respiratory or parenteral SEB challenge in murine models of SEB intoxication. Here, it is demonstrated that immunization of nonhuman primates with the proteosome-SEB toxoid vaccine is safe, immunogenic, and protective against lethal aerosol challenge with 15 50% lethal doses of SEB. Monkeys (10 per group) were primed i.m. and given booster injections by either the i.m. or intratracheal route without adverse side effects. Anamnestic anti-SEB serum immunoglobulin G (IgG) responses were elicited in all monkeys, but strong IgA responses in sera and bronchial secretions were elicited both pre- and post-SEB challenge only in monkeys given booster injections intratracheally. The proteosome-SEB toxoid vaccine was efficacious by both routes in protecting 100% of monkeys against severe symptomatology and death from aerosolized-SEB intoxication. These data confirm the safety, immunogenicity, and efficacy in monkeys of parenteral and respiratory vaccination with the proteosome-SEB toxoid, thereby supporting clinical trials of this vaccine in humans. The safety and enhancement of both bronchial and systemic IgA and IgG responses by the proteosome vaccine delivered by a respiratory route are also encouraging for the development of mucosally delivered proteosome vaccines to protect against SEB and other toxic or infectious respiratory pathogens. PMID:8890226

  6. Human plasma enhances the expression of Staphylococcal microbial surface components recognizing adhesive matrix molecules promoting biofilm formation and increases antimicrobial tolerance In Vitro

    PubMed Central

    2014-01-01

    Background Microbial biofilms have been associated with the development of chronic human infections and represent a clinical challenge given their increased antimicrobial tolerance. Staphylococcus aureus is a major human pathogen causing a diverse range of diseases, of which biofilms are often involved. Staphylococcal attachment and the formation of biofilms have been shown to be facilitated by host factors that accumulate on surfaces. To better understand how host factors enhance staphylococcal biofilm formation, we evaluated the effect of whole human plasma on biofilm formation in clinical isolates of S. aureus and the expression of seven microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) known to be involved in biofilm formation by quantitative real-time PCR. We also evaluated whether plasma augmented changes in S. aureus biofilm morphology and antimicrobial resistance. Results Exposure of clinical isolates of S. aureus to human plasma (10%) within media, and to a lesser extent when coated onto plates, significantly enhanced biofilm formation in all of the clinical isolates tested. Compared to biofilms grown under non-supplemented conditions, plasma-augmented biofilms displayed significant changes in both the biofilm phenotype and cell morphology as determined by confocal scanning laser microscopy (CLSM) and scanning electron microscopy (SEM), respectively. Exposure of bacteria to plasma resulted in a significant fold-increase in MSCRAMM expression in both a time and isolate-dependent manner. Additionally, plasma-augmented biofilms displayed an increased tolerance to vancomycin compared to biofilms grown in non-supplemented media. Conclusions Collectively, these studies support previous findings demonstrating a role for host factors in biofilm formation and provide further insight into how plasma, a preferred growth medium for staphylococcal biofilm formation enhances as well as augments other intrinsic properties of S. aureus biofilms

  7. The floating (pathogenicity) island: a genomic dessert

    PubMed Central

    Novick, Richard P.; Ram, Geeta

    2015-01-01

    Among the prokaryotic genomic islands (GIs) involved in horizontal gene transfer (HGT) are the classical pathogenicity islands, including the integrative and conjugative elements (ICEs), the gene-transfer agents (GTAs), and the staphylococcal pathogenicity islands (SaPIs), the primary focus of this review. While the ICEs and GTAs mediate HGT autonomously, the SaPIs are dependent on specific phages. The ICEs transfer primarily their own DNA the GTAs exclusively unlinked host DNA and the SaPIs combine the capabilities of both. Thus the SaPIs derive their importance from the genes they carry (their genetic cargo) and the genes they move. They act not only as versatile high frequency mobilizers, but also as mediators of phage interference, and consequently are major benefactors of their host bacteria. PMID:26744223

  8. In Vivo Efficacy of Anuran Trypsin Inhibitory Peptides against Staphylococcal Skin Infection and the Impact of Peptide Cyclization

    PubMed Central

    Malik, U.; Silva, O. N.; Fensterseifer, I. C. M.; Chan, L. Y.; Clark, R. J.; Franco, O. L.; Daly, N. L.

    2015-01-01

    Staphylococcus aureus is a virulent pathogen that is responsible for a wide range of superficial and invasive infections. Its resistance to existing antimicrobial drugs is a global problem, and the development of novel antimicrobial agents is crucial. Antimicrobial peptides from natural resources offer potential as new treatments against staphylococcal infections. In the current study, we have examined the antimicrobial properties of peptides isolated from anuran skin secretions and cyclized synthetic analogues of these peptides. The structures of the peptides were elucidated by nuclear magnetic resonance (NMR) spectroscopy, revealing high structural and sequence similarity with each other and with sunflower trypsin inhibitor 1 (SFTI-1). SFTI-1 is an ultrastable cyclic peptide isolated from sunflower seeds that has subnanomolar trypsin inhibitory activity, and this scaffold offers pharmaceutically relevant characteristics. The five anuran peptides were nonhemolytic and noncytotoxic and had trypsin inhibitory activities similar to that of SFTI-1. They demonstrated weak in vitro inhibitory activities against S. aureus, but several had strong antibacterial activities against S. aureus in an in vivo murine wound infection model. pYR, an immunomodulatory peptide from Rana sevosa, was the most potent, with complete bacterial clearance at 3 mg · kg−1. Cyclization of the peptides improved their stability but was associated with a concomitant decrease in antimicrobial activity. In summary, these anuran peptides are promising as novel therapeutic agents for treating infections from a clinically resistant pathogen. PMID:25624332

  9. A serological survey of tick-borne pathogens in dogs in North America and the Caribbean as assessed by Anaplasma phagocytophilum, A. platys, Ehrlichia canis, E. chaffeensis, E. ewingii, and Borrelia burgdorferi species-specific peptides

    PubMed Central

    Qurollo, Barbara A.; Chandrashekar, Ramaswamy; Hegarty, Barbara C.; Beall, Melissa J.; Stillman, Brett A.; Liu, Jiayou; Thatcher, Brendon; Pultorak, Elizabeth; Cerrito, Brian; Walsh, Mary; Breitschwerdt, Edward B.

    2014-01-01

    Introduction Tick-borne pathogens cause a spectrum of disease manifestations in both dogs and humans. Recognizing regional and temporal shifts in exposure are important as tick distributions change. To better delineate regional exposure to canine tick-borne pathogens, an expanded set of species-specific peptides were used to detect Anaplasma phagocytophilum (Aph), Anaplasma platys (Apl), Ehrlichia canis (Ec), Ehrlichia chaffeensis (Ech), Ehrlichia ewingii (Eew), and Borrelia burgdorferi (Bb) antibodies in canine serum. Methods Archived canine serum samples (n=6,582) collected during 2008–2010 and in 2012 from the US, Canada, and the Caribbean were retrospectively screened for antibodies against Ehrlichia and Anaplasma species-specific peptides. Overall, regional and temporal seroprevalence rates were determined. Results Overall Bb and Eew were the most seroprevalent pathogens. During 2008–2010, seroprevalence rates increased overall for Aph and Ech, and regionally, Bb and Aph seroprevalence rates increased in the South. Canada had unexpectedly high seroprevalence rates for Ec and Apl. The most common co-exposures were Eew+Ech, followed by Aph+Bb and Eew+Bb. Conclusions This study demonstrated significant shifts in canine vector-borne disease seroprevalence rates. The use of specific peptides facilitated improved geographic delineation of tick-borne pathogen distributions among dogs, which may enhance epidemiological surveillance of vector-borne pathogens shared by dogs and humans. PMID:25405006

  10. Development of a PCR-restriction fragment length polymorphism protocol for rapid detection and differentiation of four cockroach vectors (group I "Dirty 22" species) responsible for food contamination and spreading of foodborne pathogens: public health importance.

    PubMed

    Sulaiman, Irshad M; Anderson, Mickey; Khristova, Marina; Tang, Kevin; Sulaiman, Nikhat; Phifer, Edwin; Simpson, Steven; Kerdahi, Khalil

    2011-11-01

    Assessing the adulteration of food products and the presence of filth and extraneous materials is one of the measures that the U.S. Food and Drug Administration (FDA) utilizes in implementing regulatory actions of public health importance. To date, 22 common pest species (also known as the "Dirty 22" species) have been regarded by this agency as the spreaders of foodborne diseases. We have further categorized the Dirty 22 species into four groups: I has four cockroach species, II has two ant species, III has 12 fly species, and IV has four rodent species. The presence of any Dirty 22 species is also considered an indicator of unsanitary conditions in food processing and storage facilities. In this study, we describe the development of a two-step nested PCR protocol to amplify the small subunit ribosomal gene of group I Dirty 22 species that include four cockroach species: Blattella germanica, Blatta orientalis, Periplaneta americana, and Supella longipalpa, along with the development of a PCR-restriction fragment length polymorphism method for rapid detection and differentiation of these violative species. This method will be utilized when the specimen cannot be identified with conventional microscopic taxonomic methods, especially when only small body parts are separated and recovered from food samples for analysis or when these body parts are in a decomposed state. This new PCR-restriction fragment length polymorphism will provide correct identification of group I Dirty 22 species; this information can then be used in regulation and prevention of foodborne pathogens.

  11. Transcriptional analysis of the innate immune response of ducks to different species-of-origin low pathogenic H7 avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Ducks represent an important reservoir for avian influenza (AI) viruses and are partly responsible for the worldwide dissemination of AI. Due to the ability of some low pathogenicity avian influenza viruses (LPAIV) of the hemagglutinin H7 subtype to mutate into a highly pathogenic form o...

  12. Two common structural motifs for TCR recognition by staphylococcal enterotoxins

    PubMed Central

    Rödström, Karin E. J.; Regenthal, Paulina; Bahl, Christopher; Ford, Alex; Baker, David; Lindkvist-Petersson, Karin

    2016-01-01

    Superantigens are toxins produced by Staphylococcus aureus, called staphylococcal enterotoxins (abbreviated SEA to SEU). They can cross-link the T cell receptor (TCR) and major histocompatibility complex class II, triggering a massive T cell activation and hence disease. Due to high stability and toxicity, superantigens are potential agents of bioterrorism. Hence, antagonists may not only be useful in the treatment of disease but also serve as countermeasures to biological warfare. Of particular interest are inhibitors against SEA and SEB. SEA is the main cause of food poisoning, while SEB is a common toxin manufactured as a biological weapon. Here, we present the crystal structures of SEA in complex with TCR and SEE in complex with the same TCR, complemented with computational alanine-scanning mutagenesis of SEA, SEB, SEC3, SEE, and SEH. We have identified two common areas that contribute to the general TCR binding for these superantigens. This paves the way for design of single antagonists directed towards multiple toxins. PMID:27180909

  13. Sticky Matrix: Adhesion Mechanism of the Staphylococcal Polysaccharide Intercellular Adhesin.

    PubMed

    Formosa-Dague, Cécile; Feuillie, Cécile; Beaussart, Audrey; Derclaye, Sylvie; Kucharíková, Soňa; Lasa, Iñigo; Van Dijck, Patrick; Dufrêne, Yves F

    2016-03-22

    The development of bacterial biofilms on surfaces leads to hospital-acquired infections that are difficult to fight. In Staphylococci, the cationic polysaccharide intercellular adhesin (PIA) forms an extracellular matrix that connects the cells together during biofilm formation, but the molecular forces involved are unknown. Here, we use advanced force nanoscopy techniques to unravel the mechanism of PIA-mediated adhesion in a clinically relevant methicillin-resistant Staphylococcus aureus (MRSA) strain. Nanoscale multiparametric imaging of the structure, adhesion, and elasticity of bacteria expressing PIA shows that the cells are surrounded by a soft and adhesive matrix of extracellular polymers. Cell surface softness and adhesion are dramatically reduced in mutant cells deficient for the synthesis of PIA or under unfavorable growth conditions. Single-cell force spectroscopy demonstrates that PIA promotes cell-cell adhesion via the multivalent electrostatic interaction with polyanionic teichoic acids on the S. aureus cell surface. This binding mechanism rationalizes, at the nanoscale, the well-known ability of PIA to strengthen intercellular adhesion in staphylococcal biofilms. Force nanoscopy offers promising prospects for understanding the fundamental forces in antibiotic-resistant biofilms and for designing anti-adhesion compounds targeting matrix polymers.

  14. Staphylococcal biofilm formation as affected by type acidulant.

    PubMed

    Nostro, Antonia; Cellini, Luigina; Ginestra, Giovanna; D'Arrigo, Manuela; di Giulio, Mara; Marino, Andreana; Blanco, Anna Rita; Favaloro, Angelo; Bisignano, Giuseppe

    2014-07-01

    Staphylococcal growth and biofilm formation in culture medium where pH was lowered with weak organic (acetic and lactic) or strong inorganic (hydrochloric) acids were studied. The effects were evaluated by biomass measurements, cell-surface hydrophobicity, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). The results demonstrated that the inhibition was related to type of acidulant and pH value. At pH 5.0, the antibacterial effect was more pronounced in the presence of acetic acid (58-60% growth reduction) compared with that in the presence of lactic (7-16% growth reduction) and hydrochloric acids (23-24% reduction). The biofilm biomass of Staphylococcus aureus and Staphylococcus epidermidis was reduced by 92, 85, 63, and 93, 87, 81% after exposition to acetic, lactic, and hydrochloric acids, respectively. Increasing the pH from 5.0 to 6.0 resulted in a noticeable reduction in the effectiveness of acids. A minor cells hydrophobic character was also documented. The SEM and CLSM revealed a poorly structured and thinner biofilm compared with the dense and multilayered control. Acidic environment could have important implications for food-processing system to prevent bacterial colonization and control biofilm formation. The findings of this study lead to consider the rational use of the type of acid to achieve acidic environments.

  15. Ribosome hibernation factor promotes Staphylococcal survival and differentially represses translation

    PubMed Central

    Basu, Arnab; Yap, Mee-Ngan F.

    2016-01-01

    In opportunistic Gram-positive Staphylococcus aureus, a small protein called hibernation-promoting factor (HPFSa) is sufficient to dimerize 2.5-MDa 70S ribosomes into a translationally inactive 100S complex. Although the 100S dimer is observed in only the stationary phase in Gram-negative gammaproteobacteria, it is ubiquitous throughout all growth phases in S. aureus. The biological significance of the 100S ribosome is poorly understood. Here, we reveal an important role of HPFSa in preserving ribosome integrity and poising cells for translational restart, a process that has significant clinical implications for relapsed staphylococcal infections. We found that the hpf null strain is severely impaired in long-term viability concomitant with a dramatic loss of intact ribosomes. Genome-wide ribosome profiling shows that eliminating HPFSa drastically increased ribosome occupancy at the 5′ end of specific mRNAs under nutrient-limited conditions, suggesting that HPFSa may suppress translation initiation. The protective function of HPFSa on ribosomes resides at the N-terminal conserved basic residues and the extended C-terminal segment, which are critical for dimerization and ribosome binding, respectively. These data provide significant insight into the functional consequences of 100S ribosome loss for protein synthesis and stress adaptation. PMID:27001516

  16. Pelvic primary staphylococcal infection presenting as a thigh abscess.

    PubMed

    Abbas, T O

    2013-01-01

    Intra-abdominal disease can present as an extra-abdominal abscess and can follow several routes, including the greater sciatic foramen, obturator foramen, femoral canal, pelvic outlet, and inguinal canal. Nerves and vessels can also serve as a route out of the abdomen. The psoas muscle extends from the twelfth thoracic and fifth lower lumbar vertebrae to the lesser trochanter of the femur, which means that disease in this muscle group can migrate along the muscle, out of the abdomen, and present as a thigh abscess. We present a case of a primary pelvic staphylococcal infection presenting as a thigh abscess. The patient was a 60-year-old man who presented with left posterior thigh pain and fever. Physical examination revealed a diffusely swollen left thigh with overlying erythematous, shiny, and tense skin. X-rays revealed no significant soft tissue lesions, ultrasound was suggestive of an inflammatory process, and MRI showed inflammatory changes along the left hemipelvis and thigh involving the iliacus muscle group, left gluteal region, and obturator internus muscle. The abscess was drained passively via two incisions in the posterior left thigh, releasing large amounts of purulent discharge. Subsequent bacterial culture revealed profuse growth of Staphylococcus aureus. The patient recovered uneventfully except for a moderate fever on the third postoperative day.

  17. Staphylococcal enterotoxins bind H-2Db molecules on macrophages

    NASA Technical Reports Server (NTRS)

    Beharka, A. A.; Iandolo, J. J.; Chapes, S. K.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    We screened a panel of monoclonal antibodies against selected macrophage cell surface molecules for their ability to inhibit enterotoxin binding to major histocompatibility complex class II-negative C2D (H-2b) macrophages. Two monoclonal antibodies, HB36 and TIB126, that are specific for the alpha 2 domain of major histocompatibility complex class I, blocked staphylococcal enterotoxins A and B (SEA and SEB, respectively) binding to C2D macrophages in a specific and concentration-dependent manner. Inhibitory activities were haplotype-specific in that SEA and SEB binding to H-2k or H-2d macrophages was not inhibited by either monoclonal antibody. HB36, but not TIB126, inhibited enterotoxin-induced secretion of cytokines by H-2b macrophages. Lastly, passive protection of D-galactosamine-sensitized C2D mice by injection with HB36 antibody prevented SEB-induced death. Therefore, SEA and SEB binding to the alpha 2 domain of the H-2Db molecule induces biological activity and has physiological consequences.

  18. Staphylococcal cassette chromosome mec-like element in Macrococcus caseolyticus.

    PubMed

    Tsubakishita, Sae; Kuwahara-Arai, Kyoko; Baba, Tadashi; Hiramatsu, Keiichi

    2010-04-01

    Macrococcus is a bacterial genus that is closely related to Staphylococcus, which typically is isolated from animal skin and products. The genome analysis of multidrug-resistant Macrococcus caseolyticus strain JCSC5402, isolated from chicken, previously led to the identification of plasmid pMCCL2, which carries a transposon containing an unusual form of the Macrococcus mec gene complex (mecA(m)-mecR1(m)-mecI(m)-blaZ(m)). In M. caseolyticus strain JCSC7096, this mec transposon containing the mec gene complex (designated Tn6045 in this study) was found integrated downstream of orfX on the chromosome. Tn6045 of JCSC7096 was bracketed by the direct repeat sequences (DR) specifically recognized by cassette chromosome recombinase (CCR). A non-mecA-containing staphylococcal cassette chromosome (SCC) element, designated SCC(7096), was integrated next to the mec transposon and separated from the latter by a DR. Nested PCR experiments showed that the mec transposon not only was excised singly but also coexcised with SCC(7096) from the chromosome at the DRs. The coexcised elements formed the extrachromosomal closed circular DNA of the SCCmec-like element. SCCmec is known to be the mobile element conveying methicillin (meticillin) resistance in staphylococci. However, its origin has been unknown. Our observation revealed a potential mechanism of the generation of a new SCCmec-like element in M. caseolyticus, a commensal bacterium of food animals.

  19. Molecular determinants of staphylococcal biofilm dispersal and structuring

    PubMed Central

    Le, Katherine Y.; Dastgheyb, Sana; Ho, Trung V.; Otto, Michael

    2014-01-01

    Staphylococci are frequently implicated in human infections, and continue to pose a therapeutic dilemma due to their ability to form deeply seated microbial communities, known as biofilms, on the surfaces of implanted medical devices and host tissues. Biofilm development has been proposed to occur in three stages: (1) attachment, (2) proliferation/structuring, and (3) detachment/dispersal. Although research within the last several decades has implicated multiple molecules in the roles as effectors of staphylococcal biofilm proliferation/structuring and detachment/dispersal, to date, only phenol soluble modulins (PSMs) have been consistently demonstrated to serve in this role under both in vitro and in vivo settings. PSMs are regulated directly through a density-dependent manner by the accessory gene regulator (Agr) system. They disrupt the non-covalent forces holding the biofilm extracellular matrix together, which is necessary for the formation of channels, a process essential for the delivery of nutrients to deeper biofilm layers, and for dispersal/dissemination of clusters of biofilm to distal organs in acute infection. Given their relevance in both acute and chronic biofilm-associated infections, the Agr system and the psm genes hold promise as potential therapeutic targets. PMID:25505739

  20. A unique, highly conserved secretory invertase is differentially expressed by promastigote developmental forms of all species of the human pathogen, Leishmania.

    PubMed

    Lyda, Todd A; Joshi, Manju B; Andersen, John F; Kelada, Andrew Y; Owings, Joshua P; Bates, Paul A; Dwyer, Dennis M

    2015-06-01

    Leishmania are protozoan pathogens of humans that exist as extracellular promastigotes in the gut of their sand fly vectors and as obligate intracellular amastigotes within phagolysosomes of infected macrophages. Between infectious blood meal feeds, sand flies take plant juice meals that contain sucrose and store these sugars in their crop. Such sugars are regurgitated into the sand fly anterior midgut where they impact the developing promastigote parasite population. In this report we showed that promastigotes of all Leishmania species secreted an invertase/sucrase enzyme during their growth in vitro. In contrast, neither L. donovani nor L. mexicana amastigotes possessed any detectable invertase activity. Importantly, no released/secreted invertase activity was detected in culture supernatants from either Trypanosoma brucei or Trypanosoma cruzi. Using HPLC, the L. donovani secretory invertase was isolated and subjected to amino acid sequencing. Subsequently, we used a molecular approach to identify the LdINV and LmexINV genes encoding the ~72 kDa invertases produced by these organisms. Interestingly, we identified high fidelity LdINV-like homologs in the genomes of all Leishmania sp. but none were present in either T. brucei or T. cruzi. Northern blot and RT-PCR analyses showed that these genes were developmentally/differentially expressed in promastigotes but not amastigotes of these parasites. Homologous transfection studies demonstrated that these genes in fact encoded the functional secretory invertases produced by these parasites. Cumulatively, our results suggest that these secretory enzymes play critical roles in the survival/growth/development and transmission of all Leishmania parasites within their sand fly vector hosts.

  1. A unique, highly conserved secretory invertase is differentially expressed by promastigote developmental forms of all species of the human pathogen, Leishmania

    PubMed Central

    Lyda, Todd A.; Joshi, Manju B.; Andersen, John F.; Kelada, Andrew Y.; Owings, Joshua P.; Bates, Paul A.; Dwyer, Dennis M.

    2015-01-01

    Leishmania are protozoan pathogens of humans that exist as extracellular promastigotes in the gut of their sand fly vectors and as obligate intracellular amastigotes within phagolysosomes of infected macrophages. Between infectious blood meal feeds, sand flies take plant juice meals that contain sucrose and store these sugars in their crop. Such sugars are regurgitated into the sand fly anterior midgut where they impact the developing promastigote parasite population. In this report we showed that promastigotes of all Leishmania species secreted an invertase/sucrase enzyme during their growth in vitro. In contrast, neither L. donovani nor L. mexicana amastigotes possessed any detectable invertase activity. Importantly, no released/secreted invertase activity was detected in culture supernatants from either Trypanosoma brucei or Trypanosoma cruzi. Using HPLC, the L. donovani secretory invertase was isolated and subjected to amino acid sequencing. Subsequently, we used a molecular approach to identify the LdINV and LmexINV genes encoding the ~72 kDa invertases produced by these organisms. Interestingly, we identified high fidelity LdINV-like homologs in the genomes of all Leishmania sp. but none were present in either T. brucei or T. cruzi. Northern blot and RT-PCR analyses showed that these genes were developmentally/differentially expressed in promastigotes but not amastigotes of these parasites. Homologous transfection studies demonstrated that these genes in fact encoded the functional secretory invertases produced by these parasites. Cumulatively, our results suggest that these secretory enzymes play critical roles in the survival/growth/development and transmission of all Leishmania parasites within their sand fly vector hosts. PMID:25763714

  2. Monoclonal antibody-based sandwich ELISA for the detection of staphylococcal enterotoxin A.

    PubMed

    Kuang, Hua; Wang, Wenbing; Xu, Liguang; Ma, Wei; Liu, Liqiang; Wang, Libing; Xu, Chuanlai

    2013-04-19

    A sensitive and specific monoclonal antibody-based sandwich enzyme-linked immunosorbent assay (ELISA) was established and validated for the detection of staphylococcal enterotoxin A (SEA). After routine fusion and selection, 10 monoclonal antibodies showed high affinity for SEA. An optimal pair for sandwich ELISA was selected by pairwise interaction analysis. After optimization, the limit of detection (LOD) and linear dynamic range of the method were established, and were found to be 0.0282 ng/mL and 0.06-2 ng/mL, respectively. The recovery in pure milk ranged from 82.67% to 111.95% and the intra- and inter-assay coefficients of variation ranged from 3.16% to 6.05% and from 5.16% to 10.79%, respectively. Cross-reactivity with staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C (SEC), staphylococcal enterotoxin D (SED), and staphylococcal enterotoxin E (SEE) in this method were insignificant. These results indicate that the sandwich ELISA method developed in our study is effective for routine identification of SEA in food samples.

  3. Tropism and Pathogenicity of Rickettsiae

    PubMed Central

    Uchiyama, Tsuneo

    2012-01-01

    Rickettsiae are obligate intracellular parasitic bacteria that cause febrile exanthematous illnesses such as Rocky Mountain spotted fever, Mediterranean spotted fever, epidemic, and murine typhus, etc. Although the vector ranges of each Rickettsia species are rather restricted; i.e., ticks belonging to Arachnida and lice and fleas belonging to Insecta usually act as vectors for spotted fever group (SFG) and typhus group (TG) rickettsiae, respectively, it would be interesting to elucidate the mechanisms controlling the vector tropism of rickettsiae. This review discusses the factors determining the vector tropism of rickettsiae. In brief, the vector tropism of rickettsiae species is basically consistent with their tropism toward cultured tick and insect cells. The mechanisms responsible for rickettsiae pathogenicity are also described. Recently, genomic analyses of rickettsiae have revealed that they possess several genes that are homologous to those affecting the pathogenicity of other bacteria. Analyses comparing the genomes of pathogenic and non-pathogenic strains of rickettsiae have detected many factors that are related to rickettsial pathogenicity. It is also known that a reduction in the rickettsial genome has occurred during the course of its evolution. Interestingly, Rickettsia species with small genomes, such as Rickettsia prowazekii, are more pathogenic to humans than those with larger genomes. This review also examines the growth kinetics of pathogenic and non-pathogenic species of SFG rickettsiae (SFGR) in mammalian cells. The growth of non-pathogenic species is restricted in these cells, which is mediated, at least in part, by autophagy. The superinfection of non-pathogenic rickettsiae-infected cells with pathogenic rickettsiae results in an elevated yield of the non-pathogenic rickettsiae and the growth of the pathogenic rickettsiae. Autophagy is restricted in these cells. These results are discussed in this review. PMID:22737150

  4. RAGE Deficiency Impairs Bacterial Clearance in Murine Staphylococcal Sepsis, but Has No Significant Impact on Staphylococcal Septic Arthritis

    PubMed Central

    Mohammad, Majd; Na, Manli; Welin, Amanda; Svensson, Mattias N. D.; Ali, Abukar; Jin, Tao; Pullerits, Rille

    2016-01-01

    Background Septic arthritis is a serious joint disease often caused by Staphylococcus aureus (S. aureus). Receptor for Advanced Glycation End products (RAGE) has an important role in several infections. We sought to investigate the role of RAGE in staphylococcal septic arthritis and sepsis in mice. Methods Wild-type (WT) and RAGE deficient (RAGE-/-) mice were intra-articularly or intravenously inoculated with an arthritic or septic dose of S. aureus LS-1 strain. Clinical arthritis, weight development and mortality were monitored for 14 days. Serum levels of cytokines, kidney bacterial loads as well as micro-CT and histopathology of the joints were assessed. Results RAGE-/- mice with septic arthritis had significantly lower IL-17A and higher bone mineral density (BMD) compared to the control group. However, no significant differences between the groups were observed regarding the weight loss, the severity and frequency of arthritis, and bacterial loads in the kidneys. In mice with sepsis, the overall mortality rate was similar in RAGE-/- (39%) and in WT mice (45%). However, RAGE-/- mice with sepsis had significantly higher bacterial load in their kidneys compared to the WT controls. In line with data from hematogenous S. aureus arthritis, RAGE deficiency had no impact on arthritis severity in local joint infection. Conclusions Our results indicate that lack of RAGE has no significant impact on septic arthritis. However, RAGE-/- mice had significantly higher BMD compared to WT mice, which coincided with lower IL-17A in RAGE-/- mice. In sepsis, RAGE deficiency impairs bacterial kidney clearance. PMID:27907047

  5. Molecular pathogenicity of Streptococcus anginosus.

    PubMed

    Asam, D; Spellerberg, B

    2014-08-01

    Streptococcus anginosus and the closely related species Streptococcus constellatus and Streptococcus intermedius, are primarily commensals of the mucosa. The true pathogenic potential of this group has been under-recognized for a long time because of difficulties in correct species identification as well as the commensal nature of these species. In recent years, streptococci of the S. anginosus group have been increasingly found as relevant microbial pathogens in abscesses and blood cultures and they play a pathogenic role in cystic fibrosis. Several international studies have shown a surprisingly high frequency of infections caused by the S. anginosus group. Recent studies and a genome-wide comparative analysis suggested the presence of multiple putative virulence factors that are well-known from other streptococcal species. However, very little is known about the molecular basis of pathogenicity in these bacteria. This review summarizes our current knowledge of pathogenicity factors and their regulation in S. anginosus.

  6. LYSIS OF BACTERIAL PROTOPLASTS AND SPHEROPLASTS BY STAPHYLOCOCCAL ALPHA-TOXIN AND STREPTOLYSIN S.

    PubMed

    BERNHEIMER, A W; SCHWARTZ, L L

    1965-05-01

    Bernheimer, Alan W. (New York University School of Medicine, New York, N.Y.), and Lois L. Schwartz. Lysis of bacterial protoplasts and spheroplasts by staphylococcal alpha-toxin and streptolysin S. J. Bacteriol. 89:1387-1392. 1965.-Protoplasts of Bacillus megaterium, Sarcina lutea, and Streptococcus pyogenes, and spheroplasts of Escherichia coli were lysed by staphylococcal alpha-toxin, whereas spheroplasts of Vibrio metschnikovii and V. comma were not. In the spectrum of its lytic action, streptolysin S qualitatively resembled staphylococcal alpha-toxin except for failure to lyse S. pyogenes protoplasts. In contrast to the two foregoing agents, streptolysin O did not lyse protoplasts and spheroplasts. The observations are interpreted in relation to similarities and differences in lipid composition of bacterial and mammalian cell membranes.

  7. Inhibitory effects of various plant polyphenols on the toxicity of Staphylococcal alpha-toxin.

    PubMed

    Choi, Oksun; Yahiro, Kinnosuke; Morinaga, Naoko; Miyazaki, Masaru; Noda, Masatoshi

    2007-01-01

    Staphylococcal alpha-toxin, known for its wide spectrum of biological activities, is involved in the pathogenesis of Staphylococcal infectious diseases. In recent years, various phytochemicals have been found to have antimicrobiological, including antibacterial, antiviral and antifungal, and antitoxic activities. We investigated whether several plant polyphenols inhibit alpha-toxin activities in vitro and in vivo. We found hop bract tannin (HBT) and apple condensed tannin (ACT) to exert inhibitory effects on alpha-toxin cytotoxicity. HBT also reduced the murine skin inflammatory effect and the lethality of alpha-toxin. These polyphenols formed aggregates with alpha-toxin and thereby inhibited its activities. Inhibition of alpha-toxin by HBT and ACT was dose dependent, suggesting that these polyphenols may be a useful adjunct to current treatments for alpha-toxin catalyzed Staphylococcal infectious diseases.

  8. Adaptation of the staphylococcal coagglutination technique for detection of heat-labile enterotoxin of Escherichia coli.

    PubMed Central

    Brill, B M; Wasilauskas, B L; Richardson, S H

    1979-01-01

    Protein A-containing staphylococci coated with specific antiserum were tested for heat-labile enterotoxin of Escherichia coli. The immunological cross-reactivity of E. coli heat-labile enterotoxin with Vibrio cholerae toxin (choleragen) was the basis for sensitizing stabilized suspensions of the Cowan I strain of Staphylococcus aureus with anticholeragen. Unconcentrated culture supernatant fluid containing E. coli heat-labile enterotoxin produced macroscopic agglutination when mixed with sensitized staphylococci in capillary tubes. A total of 15 toxigenic and 61 nontoxigenic isolates were tested by the staphylococcal coagglutination technique in a coded fashion and found to be in agreement with previous results of the Chinese hamster ovary cell assay and the passive immune hemolysis test. The staphylococcal coagglutination technique is simple, relatively inexpensive to perform, and requires the immunoglobulin fraction of anticholeragen as the only specific reagent. The staphylococcal coagglutination technique appears to have potential for routine use in diagnostic microbiology laboratories. Images PMID:372214

  9. Host Specificity of Bacterial Pathogens

    PubMed Central

    Bäumler, Andreas; Fang, Ferric C.

    2013-01-01

    Most pathogens are able to infect multiple hosts but some are highly adapted to a single-host species. A detailed understanding of the basis of host specificity can provide important insights into molecular pathogenesis, the evolution of pathogenic microbes, and the potential for pathogens to cross the species barrier to infect new hosts. Comparative genomics and the development of humanized mouse models have provided important new tools with which to explore the basis of generalism and specialism. This review will examine host specificity of bacterial pathogens with a focus on generalist and specialist serovars of Salmonella enterica. PMID:24296346

  10. Staphylococcal Superantigens Spark Host-Mediated Danger Signals

    PubMed Central

    Krakauer, Teresa; Pradhan, Kisha; Stiles, Bradley G.

    2016-01-01

    Staphylococcal enterotoxin B (SEB) of Staphylococcus aureus, and related superantigenic toxins produced by myriad microbes, are potent stimulators of the immune system causing a variety of human diseases from transient food poisoning to lethal toxic shock. These protein toxins bind directly to specific Vβ regions of T-cell receptors (TCR) and major histocompatibility complex (MHC) class II on antigen-presenting cells, resulting in hyperactivation of T lymphocytes and monocytes/macrophages. Activated host cells produce excessive amounts of proinflammatory cytokines and chemokines, especially tumor necrosis factor α, interleukin 1 (IL-1), IL-2, interferon γ (IFNγ), and macrophage chemoattractant protein 1 causing clinical symptoms of fever, hypotension, and shock. Because of superantigen-induced T cells skewed toward TH1 helper cells, and the induction of proinflammatory cytokines, superantigens can exacerbate autoimmune diseases. Upon TCR/MHC ligation, pathways induced by superantigens include the mitogen-activated protein kinase cascades and cytokine receptor signaling, resulting in activation of NFκB and the phosphoinositide 3-kinase/mammalian target of rapamycin pathways. Various mouse models exist to study SEB-induced shock including those with potentiating agents, transgenic mice and an “SEB-only” model. However, therapeutics to treat toxic shock remain elusive as host response genes central to pathogenesis of superantigens have only been identified recently. Gene profiling of a murine model for SEB-induced shock reveals novel molecules upregulated in multiple organs not previously associated with SEB-induced responses. The pivotal genes include intracellular DNA/RNA sensors, apoptosis/DNA damage-related molecules, immunoproteasome components, as well as antiviral and IFN-stimulated genes. The host-wide induction of these, and other, antimicrobial defense genes provide evidence that SEB elicits danger signals resulting in multi-organ damage and toxic

  11. Thermodynamic characterization of an equilibrium folding intermediate of staphylococcal nuclease.

    PubMed Central

    Xie, D.; Fox, R.; Freire, E.

    1994-01-01

    High-sensitivity differential scanning calorimetry and CD spectroscopy have been used to probe the structural stability and measure the folding/unfolding thermodynamics of a Pro117-->Gly variant of staphylococcal nuclease. It is shown that at neutral pH the thermal denaturation of this protein is well accounted for by a 2-state mechanism and that the thermally denatured state is a fully hydrated unfolded polypeptide. At pH 3.5, thermal denaturation results in a compact denatured state in which most, if not all, of the helical structure is missing and the beta subdomain apparently remains largely intact. At pH 3.0, no thermal transition is observed and the molecule exists in the compact denatured state within the 0-100 degrees C temperature interval. At high salt concentration and pH 3.5, the thermal unfolding transition exhibits 2 cooperative peaks in the heat capacity function, the first one corresponding to the transition from the native to the intermediate state and the second one to the transition from the intermediate to the unfolded state. As is the case with other proteins, the enthalpy of the intermediate is higher than that of the unfolded state at low temperatures, indicating that, under those conditions, its stabilization must be of an entropic origin. The folding intermediate has been modeled by structural thermodynamic calculations. Structure-based thermodynamic calculations also predict that the most probable intermediate is one in which the beta subdomain is essentially intact and the rest of the molecule unfolded, in agreement with the experimental data. The structural features of the equilibrium intermediate are similar to those of a kinetic intermediate previously characterized by hydrogen exchange and NMR spectroscopy. PMID:7756977

  12. Compact dimension of denatured states of staphylococcal nuclease.

    PubMed

    Chow, C-Y; Wu, Ming-Chya; Fang, Huey-Jen; Hu, Chin-Kun; Chen, Hueih-Min; Tsong, Tian-Yow

    2008-08-15

    Fluorescence and circular dichroism stopped-flow have been widely used to determine the kinetics of protein folding including folding rates and possible folding pathways. Yet, these measurements are not able to provide spatial information of protein folding/unfolding. Especially, conformations of denatured states cannot be elaborated in detail. In this study, we apply the method of fluorescence energy transfer with a stopped-flow technique to study global structural changes of the staphylococcal nuclease (SNase) mutant K45C, where lysine 45 is replaced by cysteine, during folding and unfolding. By labeling the thiol group of cysteine with TNB (5,5'-dithiobis-2-nitrobenzoic acid) as an energy acceptor and the tryptophan at position 140 as a donor, distance changes between the acceptor and the donor during folding and unfolding are measured from the efficiency of energy transfer. Results indicate that the denatured states of SNase are highly compact regardless of how the denatured states (pH-induced or GdmCl-induced) are induced. The range of distance changes between two probes is between 25.6 and 25.4 A while it is 20.4 A for the native state. Furthermore, the folding process consists of three kinetic phases while the unfolding process is a single phase. These observations agree with our previous sequential model: N(0) left arrow over right arrow D(1) left arrow over right arrow D(2) left arrow over right arrow D(3) (Chen et al., J Mol Biol 1991;220:771-778). The efficiency of protein folding may be attributed to initiating the folding process from these compact denatured structures.

  13. Thermal Inactivation of Staphylococcal Enterotoxin B in Veronal Buffer

    PubMed Central

    Read, R. B.; Bradshaw, J. G.

    1966-01-01

    The times and temperatures required to inactivate staphylococcal enterotoxin B were studied by use of the double-gel-diffusion technique to assay enterotoxin. Enterotoxin B (99 +% pure) was suspended in 0.04 M Veronal buffer, dispensed into borosilicate vials, and the vials were sealed and heated in an oil bath. An amount of 30 μg/ml of this toxin was reduced to less than 0.7 μg/ml in 103.0, 87.1, 70.5, 57.2, 39.1, 27.6, 16.4, and 12.0 min, respectively, at temperatures of 96, 99, 101.7, 104.4, 110, 115.6, 121, and 126.7 C. The end point for enterotoxin inactivation by gel diffusion was identical to that by intravenous injection of cats. Limited studies with crude enterotoxin B showed that the crude preparation was slightly more thermostable. The respective D values of crude and purified enterotoxin B were 64.5 and 52.3, 40.5 and 34.4, 29.7 and 23.5, 18.8 and 16.6, and 11.4 and 9.9 min at temperatures of 99, 104.4, 110, 115.6, and 121 C. The z value for purified enterotoxin B was 32.4 C. The experimental activation energy was 20,700 cal/g mole, standard enthalpy of activation at 120 C was 19,900 cal/g mole, standard entropy of activation at 120 C was -21.4 cal/g mole K, and the standard free energy of activation at 120 C was 28,200 cal/g mole. PMID:4958146

  14. Staphylococcal scalded skin syndrome mimicking child abuse by burning.

    PubMed

    Porzionato, Andrea; Aprile, Anna

    2007-05-03

    Child abuse by burning comprises 6-20% of all child abuse cases, but misdiagnosis may arise in cases of some medical conditions. We present two cases of suspected inflicted burns, later diagnosed as staphylococcal scalded skin syndrome (SSSS). In case 1, a 6-month-old girl was referred to hospital for small round ulcerations on the face and abdomen, resembling cigarette burns. Because of the inconsistency of the mother's report (insect bites) with the injury pattern and an unstable family history, hospitalization was decided. The following day, new bullous lesions were visible on the neck and nose, indicating the natural origin of the findings, finally diagnosed as SSSS. In case 2, a 2-month-old boy was hospitalized for erythema, with bullous lesions on the abdomen. He was transferred to another hospital, with suspected congenital or autoimmune skin disorder but negative searches led to a diagnosis of inflicted scalds: a report was sent to the judicial authorities, and the child was entrusted to his grandparents. In fact, a review of the clinical documentation showed that, in the second hospitalization, new erythematous and bullous lesions had been described, which could not be ascribed to inflicted injuries. Child abuse was finally ruled out, and SSSS was diagnosed. In cases of suspected inflicted child burns, observation during hospitalization may reveal changes in lesions, ascribed to the evolution of medical conditions. SSSS diagnosis is mainly based on clinical grounds but, if the suspicion of abuse remains, isolation and phage typing of Staphylococcus aureus from nasal, pharyngeal or cutaneous swabs may confirm the diagnosis.

  15. Reference-compensated surface plasmon resonance biosensor for detection of foodborne pathogens

    NASA Astrophysics Data System (ADS)

    Homola, Jiri; Dostalek, Jakub; Chen, Shengfu; Rasooly, Avraham; Jiang, Shaoyi; Yee, Sinclair S.

    2001-05-01

    We present a dual-channel surface plasmon resonance (SPR) biosensor and demonstrate its applicability to detection of foodborne pathogens such as Staphylococcal enterotoxin B (SEB). Experimental results indicate that the SPR biosensor can detect SEB at very low concentrations: 5 ng/ml in pure samples directly, 0.5 ng/ml in both pure samples and in milk using a sandwich assay.

  16. Genetic dissection of a TIR-NB-LRR locus from the wild North American grapevine species Muscadinia rotundifolia identifies paralogous genes conferring resistance to major fungal and oomycete pathogens in cultivated grapevine.

    PubMed

    Feechan, Angela; Anderson, Claire; Torregrosa, Laurent; Jermakow, Angelica; Mestre, Pere; Wiedemann-Merdinoglu, Sabine; Merdinoglu, Didier; Walker, Amanda R; Cadle-Davidson, Lance; Reisch, Bruce; Aubourg, Sebastien; Bentahar, Nadia; Shrestha, Bipna; Bouquet, Alain; Adam-Blondon, Anne-Françoise; Thomas, Mark R; Dry, Ian B

    2013-11-01

    The most economically important diseases of grapevine cultivation worldwide are caused by the fungal pathogen powdery mildew (Erysiphe necator syn. Uncinula necator) and the oomycete pathogen downy mildew (Plasmopara viticola). Currently, grapegrowers rely heavily on the use of agrochemicals to minimize the potentially devastating impact of these pathogens on grape yield and quality. The wild North American grapevine species Muscadinia rotundifolia was recognized as early as 1889 to be resistant to both powdery and downy mildew. We have now mapped resistance to these two mildew pathogens in M. rotundifolia to a single locus on chromosome 12 that contains a family of seven TIR-NB-LRR genes. We further demonstrate that two highly homologous (86% amino acid identity) members of this gene family confer strong resistance to these unrelated pathogens following genetic transformation into susceptible Vitis vinifera winegrape cultivars. These two genes, designated resistance to Uncinula necator (MrRUN1) and resistance to Plasmopara viticola (MrRPV1) are the first resistance genes to be cloned from a grapevine species. Both MrRUN1 and MrRPV1 were found to confer resistance to multiple powdery and downy mildew isolates from France, North America and Australia; however, a single powdery mildew isolate collected from the south-eastern region of North America, to which M. rotundifolia is native, was capable of breaking MrRUN1-mediated resistance. Comparisons of gene organization and coding sequences between M. rotundifolia and the cultivated grapevine V. vinifera at the MrRUN1/MrRPV1 locus revealed a high level of synteny, suggesting that the TIR-NB-LRR genes at this locus share a common ancestor.

  17. Crystal Structure of Staphylococcal Enterotoxin G (SEG) in Complex with a Mouse T-cell Receptor Beta Chain

    SciTech Connect

    Fernandez, M.M.; Robinson, H.; Cho, S.; De Marzi, M. C.; Kerzic, M. C.; Mariuzza, R. A.; Malchiodi, E. L.

    2011-01-14

    Superantigens (SAgs) are bacterial or viral toxins that bind MHC class II (MHC-II) molecules and T-cell receptor (TCR) in a nonconventional manner, inducing T-cell activation that leads to inflammatory cytokine production, which may result in acute toxic shock. In addition, the emerging threat of purpura fulminans and community-associated meticillin-resistant Staphylococcus aureus emphasizes the importance of a better characterization of SAg binding to their natural ligands that may allow the development of reagents to neutralize their action. The three-dimensional structure of the complex between a mouse TCR {beta} chain (mV{beta}8.2) and staphylococcal enterotoxin G (SEG) at 2.0 {angstrom} resolution revealed a binding site that does not conserve the 'hot spots' present in mV{beta}8.2-SEC2, mV{beta}8.2-SEC3, mV{beta}8.2-SEB, and mV{beta}8.2-SPEA complexes. Analysis of the mV{beta}8.2-SEG interface allowed us to explain the higher affinity of this complex compared with the others, which may account for the early activation of T-cells bearing mV{beta}8.2 by SEG. This mode of interaction between SEG and mV{beta}8.2 could be an adaptive advantage to bestow on the pathogen a faster rate of colonization of the host.

  18. Crystal Structure of Staphylococcal Enterotoxin G (SEG) in Complex with a Mouse T-cell Receptor β Chain*

    PubMed Central

    Fernández, Marisa M.; Cho, Sangwoo; De Marzi, Mauricio C.; Kerzic, Melissa C.; Robinson, Howard; Mariuzza, Roy A.; Malchiodi, Emilio L.

    2011-01-01

    Superantigens (SAgs) are bacterial or viral toxins that bind MHC class II (MHC-II) molecules and T-cell receptor (TCR) in a nonconventional manner, inducing T-cell activation that leads to inflammatory cytokine production, which may result in acute toxic shock. In addition, the emerging threat of purpura fulminans and community-associated meticillin-resistant Staphylococcus aureus emphasizes the importance of a better characterization of SAg binding to their natural ligands that may allow the development of reagents to neutralize their action. The three-dimensional structure of the complex between a mouse TCR β chain (mVβ8.2) and staphylococcal enterotoxin G (SEG) at 2.0 Å resolution revealed a binding site that does not conserve the “hot spots” present in mVβ8.2-SEC2, mVβ8.2-SEC3, mVβ8.2-SEB, and mVβ8.2-SPEA complexes. Analysis of the mVβ8.2-SEG interface allowed us to explain the higher affinity of this complex compared with the others, which may account for the early activation of T-cells bearing mVβ8.2 by SEG. This mode of interaction between SEG and mVβ8.2 could be an adaptive advantage to bestow on the pathogen a faster rate of colonization of the host. PMID:21059660

  19. The Staphylococcal Toxins γ-Hemolysin AB and CB Differentially Target Phagocytes by Employing Specific Chemokine Receptors

    PubMed Central

    Spaan, András N.; Vrieling, Manouk; Wallet, Pierre; Badiou, Cédric; Reyes-Robles, Tamara; Ohneck, Elizabeth A.; Benito, Yvonne; de Haas, Carla J.C.; Day, Christopher J.; Jennings, Michael P.; Lina, Gérard; Vandenesch, François; van Kessel, Kok P.M.; Torres, Victor J.; van Strijp, Jos A.G.; Henry, Thomas

    2014-01-01

    Evasion of the host phagocyte response by Staphylococcus aureus is crucial to successful infection with the pathogen. γ-Hemolysin AB and CB (HlgAB, HlgCB) are bicomponent pore-forming toxins present in almost all human S. aureus isolates. Cellular tropism and contribution of the toxins to S. aureus pathophysiology are poorly understood. Here, we identify the chemokine receptors CXCR1, CXCR2 and CCR2 as targets for HlgAB, and the complement receptors C5aR and C5L2 as targets for HlgCB. The receptor expression patterns allow the toxins to efficiently and differentially target phagocytic cells. Murine neutrophils are resistant to HlgAB and HlgCB. CCR2 is the sole murine receptor orthologue compatible with γ-Hemolysin. In a murine peritonitis model, HlgAB contributes to S. aureus bacteremia in a CCR2-dependent manner. HlgAB-mediated targeting of CCR2+ cells highlights the involvement of inflammatory macrophages during S. aureus infection. Functional quantification identifies HlgAB and HlgCB as major secreted staphylococcal leukocidins. PMID:25384670

  20. Therapy of staphylococcal infections with cefamandole or vancomycin alone or with a combination of cefamandole and tobramycin.

    PubMed Central

    Coppens, L; Hanson, B; Klastersky, J

    1983-01-01

    Eighty adult patients with microbiologically demonstrated staphylococcal infections were included in a comparative trial of cefamandole and cefamandole plus tobramycin. Patients with cefamandole-resistant pathogens were treated with vancomycin, if the initial therapy consisted of cefamandole, but were continued on cefamandole plus tobramycin if already started on that combination. Of the patients infected with cefamandole-susceptible strains, 91% (20/22) responded favorably to treatment with cefamandole alone, and 88% (30/34) responded favorably to cefamandole plus tobramycin. Of the patients infected with cefamandole-resistant staphylococci, 70% (7/10) responded to treatment with cefamandole plus tobramycin, and 86% (12/14) responded to treatment with vancomycin, even though vancomycin therapy was started 24 to 48 h later than cefamandole-plus-tobramycin therapy. No major side effects were observed; however, cefamandole plus tobramycin was associated with a rise in the serum creatinine level in 11% (4/44) of the patients. The bactericidal activity of the serum in cefamandole-treated patients and in cefamandole-plus-tobramycin-treated patients was identical against cefamandole-susceptible strains. Against cefamandole-resistant strains, 87% of the vancomycin-containing sera were bactericidal at a dilution of 1:8, whereas only 57% of the cefamandole-plus-tobramycin-containing sera were active at that dilution. PMID:6550482

  1. Antibodies to staphylococcal peptidoglycan and its peptide epitopes, teichoic acid, and lipoteichoic acid in sera from blood donors and patients with staphylococcal infections.

    PubMed Central

    Wergeland, H I; Haaheim, L R; Natås, O B; Wesenberg, F; Oeding, P

    1989-01-01

    Antibodies to the staphylococcal antigens peptidoglycan, beta-ribitol teichoic acid, and lipoteichoic acid, as well as to the peptidoglycan epitopes L-Lys-D-Ala-D-Ala, L-Lys-D-Ala, and pentaglycine, were found over a wide range of concentrations in sera from both blood donors and patients with verified or suspected staphylococcal infections. The patient group was heterogeneous with regard to both age and type of staphylococcal infections, being representative for sera sent to our laboratory. In single-antigen assays antibodies to pentaglycine had the highest predictive positive value (67%), although only 32% of the patients had elevated levels of such antibodies. Combinations of test antigens could yield positive predictive values as high as 100%, but then the fraction of positive sera was low. Indeed, the fraction of patient sera which was positive in multiple-antigen tests never exceeded 61%. The clinical usefulness of these seroassays for identifying Staphylococcus aureus as a causative agent was limited, owing to the considerable overlap in the range of antibody concentrations between patient and blood donor sera. PMID:2473994

  2. DISINFECTION OF EMERGING PATHOGENS

    EPA Science Inventory

    There is a growing awareness of the need to control waterborne microbial pathogens. This presentation will concentate on the role of chemical inactivation, using chlorine, chloramines and ozone as a means of controlling bacterial and protozoan species. Information will be present...

  3. Pathogenicity and virulence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many pathogenic microorganisms are host-specific in that they parasitize only one or a few animal species. For example, the cause of equine strangles, Streptococcus equi subspecies equi, is essentially limited to infection of horses. Others—certain Salmonella serotypes, for example—have a broad host...

  4. Development of a new pentaplex real-time PCR assay for the identification of poly-microbial specimens containing Staphylococcus aureus and other staphylococci, with simultaneous detection of staphylococcal virulence and methicillin resistance markers.

    PubMed

    Okolie, Charles E; Wooldridge, Karl G; Turner, David P; Cockayne, Alan; James, Richard

    2015-06-01

    Staphylococcus aureus strains harbouring genes encoding virulence and antibiotic resistance are of public health importance. In clinical samples, pathogenic S. aureus is often mixed with putatively less pathogenic coagulase-negative staphylococci (CoNS), both of which can harbour mecA, the gene encoding staphylococcal methicillin-resistance. There have been previous attempts at distinguishing MRSA from MRCoNS, most of which were based on the detection of one of the pathognomonic markers of S. aureus, such as coa, nuc or spa. That approach might suffice for discrete colonies and mono-microbial samples; it is inadequate for identification of clinical specimens containing mixtures of S. aureus and CoNS. In the present study, a real-time pentaplex PCR assay has been developed which simultaneously detects markers for bacteria (16S rRNA), coagulase-negative staphylococcus (cns), S. aureus (spa), Panton-Valentine leukocidin (pvl) and methicillin resistance (mecA). Staphylococcal and non-staphylococcal bacterial strains (n = 283) were used to validate the new assay. The applicability of this test to clinical samples was evaluated using spiked blood cultures (n = 43) containing S. aureus and CoNS in mono-microbial and poly-microbial models, which showed that the 5 markers were all detected as expected. Cycling completes within 1 h, delivering 100% specificity, NPV and PPV with a detection limit of 1.0 × 10(1) to 3.0 × 10(1) colony forming units (CFU)/ml, suggesting direct applicability in routine diagnostic microbiology. This is the most multiplexed real-time PCR-based PVL-MRSA assay and the first detection of a unique marker for CoNS without recourse to the conventional elimination approach. There was no evidence that this new assay produced invalid/indeterminate test results.

  5. Staphylococcal meningitis can present as an abscess of a single lateral ventricle.

    PubMed

    Robinson, E N

    1993-03-01

    Ventricular obstruction and hydrocephalus are recognized complications of neurosurgical procedures and meningitis that has been previously treated. The confinement of bacterial meningitis solely to a lateral ventricle in an otherwise healthy individual, however, is rare. I describe a case in which a ventricular abscess occurred as the presenting manifestation of staphylococcal meningitis in a man who had no history of head trauma or neurosurgery.

  6. In vitro cell based assay for activity analysis of staphylococcal enterotoxin A in food

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Staphylococcal enterotoxins (SEs) are a leading cause of food poisoning. They function both as toxins that cause gastroenteritis after ingestion and as superantigens that non-specifically activate large numbers of T cells. Monkey or kitten bioassays were historically developed for analysis of SE act...

  7. Rifamycin Derivatives Are Effective Against Staphylococcal Biofilms In Vitro and Elutable From PMMA

    DTIC Science & Technology

    2015-04-21

    in such fractures. Rifamycins have activity against biofilms and are an effective treatment for osteoarticular infections involv- ing staphylococcal...have in the prevention and treatment of infections involving biofilms. Introduction Extremity injuries account for the majority of wounds sustained...these fractures are classified as open, resulting from penetration of fragments secondary to a primary blast [43, 44]. Infection resulting from multidrug

  8. Staphylococcal toxic shock syndrome presenting as acute respiratory distress and cor pulmonale.

    PubMed

    Zaki, S A; Shanbag, P; Chavan, V; Shenoy, P

    2010-01-01

    We describe a 7-year-old boy with staphylococcal toxic shock syndrome who presented with acute respiratory distress and cor pulmonale. We wish to highlight this unusual presentation as the diagnosis of toxic shock syndrome depends chiefly on a high degree of clinical suspicion. Early diagnosis and prompt institution of appropriate therapy will significantly reduce morbidity and mortality.

  9. LysK CHAP endopeptidase domain is required for lysis of live staphylococcal cells.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    LysK is a staphylococcal bacteriophage endolysin composed of three domains, an N-terminal cysteine, histidine-dependent amidohydrolases/peptidases (CHAP) endopeptidase domain (cleaves between D-alanine of the stem peptide and glycine of the cross-bridge peptide) a mid-protein amidase 2 domain (N-ace...

  10. A summary of staphylococcal C-terminal SH3b_5 cell wall binding domains.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Staphylococcal peptidoglycan hydrolases are a potential new source of antimicrobials. A large subset of these proteins contain a C-terminal SH3b_5 cell wall binding domain that has been shown for some to be essential for accurate cell wall recognition and subsequent staphylolytic activity, propert...

  11. Pathogenicity and transmission study of the first U.S. parrot H5N2 virus of Mexican lineage in different poultry species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2004, a low pathogenic H5N2 influenza virus was identified in a psittacine bird for the first time in the United States. Sequence and phylogenetic analysis of the hemagglutinin gene grouped the parrot isolate under the Mexican lineage H5N2 viruses (Subgroup B) with highest similarity to recent c...

  12. Variability in pathobiology of South Korean H5N1 high-pathogenicity avian influenza virus infection for 5 species of migratory waterfowl

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biological outcome of H5N1 high pathogenicity avian influenza (HPAI) virus infection in wild waterfowl is poorly understood. This study examined infectivity and pathobiology of A/chicken/Korea/IS/06 (H5N1) HPAI virus infection in Mute swans (Cygnus olor), Greylag geese (Anser anser), Ruddy Sheld...

  13. A novel electrochemical immunosensor based on magnetosomes for detection of staphylococcal enterotoxin B in milk.

    PubMed

    Wu, Longyun; Gao, Bo; Zhang, Fang; Sun, Xiulan; Zhang, Yinzhi; Li, Zaijun

    2013-03-15

    In this paper, a novel electrochemical immunosensor to detect staphylococcal enterotoxin B based on bio-magnetosomes, polyaniline nano-gold composite and 1,2-dimethyl-3-butylimidazolium hexafluorophosphate ionic liquid, was developed, and found to exhibit high sensitivity and stability. The specific antibody to staphylococcal enterotoxin B conjugated with the magnetosomes showed rapid immunoreactions and good dispersion, which contributed to the formation of a nanostructurally smooth and dense film on the surface of a gold electrode. Polyaniline nano-gold composite and 1,2-dimethyl-3-butylimidazolium hexafluorophosphate ionic liquid were used to modify the electrode as mediators to improve the electron transfer and offer an excellent biocompatible microenvironment for the antibody to retain its activity to enhance the response of the electrochemical sensor. Under optimal conditions, the developed immunosensor showed a good linear response in the range from 0.05 to 5 ng/mL (R(2)=0.9957) with a detection limit as low as 0.017 ng/mL, compared with the one without magnetosomes (0.05-5 ng/mL, 0.033 ng/mL), this developed immunosensor showed a wider response range and a reduced detection limit. And a good specificity with little adsorption to staphylococcal enterotoxin A, C and Na(+), K(+), Ca(2+) was obtained. Moreover, the immunosensor exhibited a good long-time stability at 4 °C reaching up to 60 days, which showed a relatively long working life. Meanwhile the immunosensor could be regenerated four times using NaOH elution. The sensor also displayed a good repeatability with a relative standard deviation of 5.02% for staphylococcal enterotoxin B detection (1 ng/mL, n=9). Furthermore, high recoveries in milk samples from 81% to 118% were achieved and successfully applied to milk sample detection. The obtained results demonstrate that the developed electrochemical immunosensor is a promising tool for the detection of staphylococcal enterotoxin B in food.

  14. Using MALDI-TOF Mass Spectrometry to Identify Drug Resistant Staphylococcal Isolates from Nonhospital Environments in Brunei Darussalam

    PubMed Central

    Chong, Ko S.; Shazali, Siti A.; Xu, Zhen; Cutler, Ronald R.; Idris, Adi

    2016-01-01

    Drug resistant bacteria have been a growing threat to the community and hospitals due to the misuse of antibiotics by humans, industrialization, and lack of novel antimicrobials currently available. Little is known about the prevalence of drug resistant bacteria in nonhealthcare environments in Brunei Darussalam and about how antibiotic resistant genes are transferred within these environments. Human contact points from different types of environments in Brunei Darussalam, varying from urban to jungle settings, were swabbed and cultured onto selective media to isolate staphylococci bacteria before performing antimicrobial susceptibility testing on the isolates. The identity of the isolates was determined using MALDI-TOF mass spectrometry (MS). Staphylococci isolates resistant to oxacillin were further tested for their minimum inhibitory concentration (MIC). PCR analysis of the mecA gene, a gene that confers resistance to oxacillin, is done to determine the level of resistance to oxacillin. Ten different staphylococcal species were identified by MALDI-TOF-MS analysis. Out of the 36 staphylococci isolates, 24 were resistant to multiple antibiotics including two isolates which were oxacillin resistant. Some staphylococci isolates had similar antibiotic resistance profiles to other staphylococci isolates of different species in the same location. This work provides the first-ever evidence of drug resistant staphylococci in the nonhospital environment in Brunei Darussalam. PMID:27127505

  15. Assessment of the bacterial diversity of human colostrum and screening of staphylococcal and enterococcal populations for potential virulence factors.

    PubMed

    Jiménez, Esther; Delgado, Susana; Fernández, Leonides; García, Natalia; Albújar, Mar; Gómez, Adolfo; Rodríguez, Juan M

    2008-01-01

    In contrast to breast milk, little is known about the bacterial composition of human colostrum. The objective of this work was to analyze the bacterial diversity of colostrum obtained from healthy women and to characterize the dominant bacterial species for the presence of possible virulence factors. Samples of colostrum obtained from 36 healthy women were inoculated into different culture media. Several isolates from each medium were selected and identified. Staphylococcal and enterococcal isolates were submitted to genetic profiling. One representative of each profile was included in a genetic and phenotypic characterization scheme, including detection of potential virulence traits/genes and sensitivity to antibiotics. Staphylococcus epidermidis and Enterococcus faecalis were the dominant species, followed by Streptococcus mitis, Propionibacterium acnes and Staphylococcus lugdunensis. Among the 48 S. epidermidis isolates selected on the basis of their genetic profiles, the biofilm-related icaD gene and the mecA gene were detected in only 11 and six isolates, respectively. In parallel, 10 enterococcal isolates were also characterized and none of them contained the cylA, vanA, vanB, vanD, vanE and vanG genes. All of them were sensitive to vancomycin. There were no indications that the colostrum samples contained harmful bacteria.

  16. Pathogenicity, morphology, and differentiation of Acanthamoeba.

    PubMed

    Khan, N A

    2001-12-01

    Acanthamoeba keratitis is sight threatening corneal infection caused by pathogenic Acanthamoeba. Previous studies have shown the genotypic differences between pathogenic and non-pathogenic species/strains of Acanthamoeba. In this study, we examined the morphological differences between pathogenic and non-pathogenic species/strains using scanning electron microscopy. Pathogenic Acanthamoeba exhibited higher number of acanthopodia (structures associated with the binding of amoeba to the target cells) as compared to non-pathogens. In addition, interactions of amoeba with the corneal epithelial cells were studied. Only pathogenic amoeba exhibited adhesion to epithelial cells. Further results indicated that phagocytosis occurs in the pathogenic amoeba by the formation of amoebastome (characteristic of amoeba phagocyte). This study showed that Acanthamoeba phagocytosis may be both an efficient means of obtaining nutrients for the amoeba and a significant factor in the pathogenesis of Acanthamoeba infections.

  17. Outbreak of staphylococcal food poisoning among children and staff at a Swiss boarding school due to soft cheese made from raw milk.

    PubMed

    Johler, Sophia; Weder, Delphine; Bridy, Claude; Huguenin, Marie-Claude; Robert, Luce; Hummerjohann, Jörg; Stephan, Roger

    2015-05-01

    On October 1, 2014, children and staff members at a Swiss boarding school consumed Tomme, a soft cheese produced from raw cow milk. Within the following 7h, all 14 persons who ingested the cheese fell ill, including 10 children and 4 staff members. Symptoms included abdominal pain and violent vomiting, followed by severe diarrhea and fever. We aim to present this food poisoning outbreak and characterize the causative agent. The duration of the incubation period was dependent of the age of the patient: 2.5h in children under 10 yr of age, 3.5h in older children and teenagers, and 7h in adults. The soft cheese exhibited low levels of staphylococcal enterotoxin (SE) A (>6ng of SEA/g of cheese) and high levels of staphylococcal enterotoxin D (>200ng of SED/g of cheese). Counts of 10(7) cfu of coagulase-positive staphylococci per gram of cheese were detected, with 3 different Staphylococcus aureus strains being present at levels >10(6) cfu/g. The 3 strains were characterized using spa typing and a DNA microarray. An enterotoxin-producing strain exhibiting sea and sed was identified as the source of the outbreak. The strain was assigned to spa type tbl 3555 and clonal complex 8, and it exhibited genetic criteria consistent with the characteristics of a genotype B strain. This genotype comprises bovine Staph. aureus strains exclusively associated with very high within-herd prevalence of mastitis and has been described as a major contaminant in Swiss raw milk cheese. It is therefore highly likely that the raw milk used for Tomme production was heavily contaminated with Staph. aureus and that levels further increased due to growth of the organism and physical concentration effects during the cheese-making process. Only a few staphylococcal food poisoning outbreaks involving raw milk products have been described. Still, in view of this outbreak and the possible occurrence of other foodborne pathogens in bovine milk, consumption of raw milk and soft cheese produced from raw

  18. Colonization, pathogenicity, host susceptibility, and therapeutics for Staphylococcus aureus: what is the clinical relevance?

    PubMed

    Tong, Steven Y C; Chen, Luke F; Fowler, Vance G

    2012-03-01

    Staphylococcus aureus is a human commensal that can also cause a broad spectrum of clinical disease. Factors associated with clinical disease are myriad and dynamic and include pathogen virulence, antimicrobial resistance, and host susceptibility. Additionally, infection control measures aimed at the environmental niches of S. aureus and therapeutic advances continue to impact upon the incidence and outcomes of staphylococcal infections. This review article focuses on the clinical relevance of advances in our understanding of staphylococcal colonization, virulence, host susceptibility, and therapeutics. Over the past decade key developments have arisen. First, rates of nosocomial methicillin-resistant S. aureus (MRSA) infections have significantly declined in many countries. Second, we have made great strides in our understanding of the molecular pathogenesis of S. aureus in general and community-associated MRSA in particular. Third, host risk factors for invasive staphylococcal infections, such as advancing age, increasing numbers of invasive medical interventions, and a growing proportion of patients with healthcare contact, remain dynamic. Finally, several new antimicrobial agents active against MRSA have become available for clinical use. Humans and S. aureus co-exist, and the dynamic interface between host, pathogen, and our attempts to influence these interactions will continue to rapidly change. Although progress has been made in the past decade, we are likely to face further surprises such as the recent waves of community-associated MRSA.

  19. Complement C5a Generation by Staphylococcal Biofilms

    PubMed Central

    Satorius, Ashley E.; Szafranski, Jacob; Pyne, Derek; Ghanesan, Mahesh; Solomon, Michael J.; Newton, Duane W.; Bortz, David M.

    2013-01-01

    Biofilms production is a central feature of nosocomial infection of catheters and other medical devices used in resuscitation and critical care. However, the very effective biofilm forming pathogen Staphylococcus epidermidis often produces a modest host inflammatory response and few of the signs and symptoms associated with more virulent pathogens. To examine the impact of bacterial biofilm formation on provocation of an innate immune response, we studied the elaboration of the major complement anaphylatoxin C5a by human serum upon contact with S. epidermidis biofilms. Wildtype S. epidermidis and mutants of sarA (a regulatory protein that promotes synthesis of the biofilm-forming polysaccharide intercellular adhesin, PIA) and icaB (responsible for post-export processing of PIA) were studied. C5a release, as a function of exposed biofilm surface area, was on the order of 1 fmol cm−2 sec−1 and was dependent on the presence of PIA. Experimental results were used to inform a physiologically-based pharmacokinetic model of C5a release by an infected central venous catheter, one of S. epidermidis' primary means of causing human disease. These simulations revealed that the magnitude of C5a release on a superior vena cava catheter completely covered with S. epidermidis would be lower than necessary to alert circulating leukocytes. Combined, the experimental and computational results are highly consistent with clinical observations in which the clinical signs of central line associated bloodstream infection are often muted in association with this important pathogen. PMID:23459111