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  • 1
    Language: English
    In: The Lancet Global Health, July 2014, Vol.2(7), pp.e387-e387
    Keywords: Public Health
    ISSN: 2214-109X
    E-ISSN: 2214-109X
    Source: ScienceDirect Journals (Elsevier)
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  • 2
    In: PLoS Neglected Tropical Diseases, 2016, Vol.10(12)
    Description: Background Haemophilus ducreyi has emerged as a major cause of cutaneous ulcers (CU) in yaws-endemic regions of the tropics in the South Pacific, South East Asia and Africa. H . ducreyi was once thought only to cause the genital ulcer (GU) disease chancroid; GU strains belong to 2 distinct classes, class I and class II. Using whole-genome sequencing of 4 CU strains from Samoa, 1 from Vanuatu and 1 from Papua New Guinea, we showed that CU strains diverged from the class I strain 35000HP and that one CU strain expressed β-lactamase. Recently, the Center for Disease Control and Prevention released the genomes of 11 additional CU strains from Vanuatu and Ghana; however, the evolutionary relationship of these CU strains to previously-characterized CU and GU strains is unknown. Methodology/Principal Findings We performed phylogenetic analysis of 17 CU and 10 GU strains. Class I and class II GU strains formed two distinct clades. The class I strains formed two subclades, one containing 35000HP and HD183 and the other containing the remainder of the class I strains. Twelve of the CU strains formed a subclone under the class I 35000HP subclade, while 2 CU strains formed a subclone under the other class I subclade. Unexpectedly, 3 of the CU strains formed a subclone under the class II clade. Phylogenetic analysis of dsrA - hgbA - ncaA sequences yielded a tree similar to that of whole-genome phylogenetic tree. Conclusions/Significance CU strains diverged from multiple lineages within both class I and class II GU strains. Multilocus sequence typing of dsrA - hgbA - ncaA could be reliably used for epidemiological investigation of CU and GU strains. As class II strains grow relatively poorly and are relatively more susceptible to vancomycin than class I strains, these findings have implications for methods to recover CU strains. Comparison of contemporary CU and GU isolates would help clarify the relationship between these entities. Author Summary Cutaneous ulcers (CU) in children in yaws-endemic regions have long been attributed to Treponema pallidum subsp. pertenue ; however, recent studies show that Haemophilus ducreyi is an important cause of CU in these regions. H . ducreyi was once thought to cause only the genital ulcer (GU) disease chancroid; phylogenetically, GU strains belong to two distinct classes called class I and class II. We previously showed that CU strains obtained from Samoa, Vanuatu and Papua New Guinea are genetically almost identical to class 1 GU strains. In this study, using published genomes from 11 additional CU strains from Ghana and Vanuatu, we show that CU strains diverged from both class I and class II GU strains and that multiple CU clones may circulate in endemic areas. These findings have implications for epidemiological typing and recovery of H . ducreyi strains from both CU and GU clinical samples.
    Keywords: Research Article ; Biology And Life Sciences ; Research And Analysis Methods ; Medicine And Health Sciences ; Medicine And Health Sciences ; Medicine And Health Sciences ; Medicine And Health Sciences ; Biology And Life Sciences ; Medicine And Health Sciences ; People And Places ; Biology And Life Sciences ; Biology And Life Sciences ; Biology And Life Sciences ; Research And Analysis Methods ; Biology And Life Sciences
    ISSN: 1935-2727
    E-ISSN: 1935-2735
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  • 3
    Language: English
    In: PloS one, 2015, Vol.10(4), pp.e0124373
    Description: Haemophilus ducreyi resists the cytotoxic effects of human antimicrobial peptides (APs), including α-defensins, β-defensins, and the cathelicidin LL-37. Resistance to LL-37, mediated by the sensitive to antimicrobial peptide (Sap) transporter, is required for H. ducreyi virulence in humans. Cationic APs are attracted to the negatively charged bacterial cell surface. In other gram-negative bacteria, modification of lipopolysaccharide or lipooligosaccharide (LOS) by the addition of positively charged moieties, such as phosphoethanolamine (PEA), confers AP resistance by means of electrostatic repulsion. H. ducreyi LOS has PEA modifications at two sites, and we identified three genes (lptA, ptdA, and ptdB) in H. ducreyi with homology to a family of bacterial PEA transferases. We generated non-polar, unmarked mutants with deletions in one, two, or all three putative PEA transferase genes. The triple mutant was significantly more susceptible to both α- and β-defensins; complementation of all three genes restored parental levels of AP resistance. Deletion of all three PEA transferase genes also resulted in a significant increase in the negativity of the mutant cell surface. Mass spectrometric analysis revealed that LptA was required for PEA modification of lipid A; PtdA and PtdB did not affect PEA modification of LOS. In human inoculation experiments, the triple mutant was as virulent as its parent strain. While this is the first identified mechanism of resistance to α-defensins in H. ducreyi, our in vivo data suggest that resistance to cathelicidin LL-37 may be more important than defensin resistance to H. ducreyi pathogenesis.
    Keywords: Bacterial Proteins -- Genetics ; Drug Resistance, Bacterial -- Genetics ; Ethanolaminephosphotransferase -- Genetics ; Haemophilus Ducreyi -- Genetics ; Lipid A -- Metabolism
    E-ISSN: 1932-6203
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  • 4
    Language: English
    In: Int. J. of Computational Biology and Drug Design, 2014, Vol 7 Issue 2/3, pp 195 - 213
    Description: High throughput bacterial RNA-Seq experiments can generate extremely high and imbalanced sequencing coverage. Over- or under-estimation of gene expression levels will hinder accurate gene differential expression analysis. Here we evaluated strategies to identify expression differences of genes with high coverage in bacterial transcriptome data using either raw sequence reads or unique reads with duplicate fragments removed. In addition, we proposed a generalised linear model (GLM) based approach to identify imbalance in read coverage based on sequence compositions. Our results show that analysis using raw reads identifies more differentially expressed genes with more accurate fold change than using unique reads. We also demonstrate the presence of sequence composition related biases that are independent of gene expression levels and experimental conditions. Finally, genes that still show strong coverage imbalance after correction were tagged using statistical approach.
    Keywords: bacterial transcriptome sequencing; RNA-Seq; gene differential expression; coverage imbalance; tri-nucleotides; GLM; generalised linear modelling; computational biology; RNA sequences; gene expression levels.
    ISSN: 1756-0756
    ISSN: 17560756
    ISSN: 1756-0764
    ISSN: 17560764
    E-ISSN: 1756-0764
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  • 5
    Language: English
    In: The Journal of infectious diseases, 15 June 2011, Vol.203(12), pp.1859-65
    Description: Haemophilus ducreyi 35000HP contains a homolog of the CpxRA 2-component signal transduction system, which controls the cell envelope stress response system in other gram-negative bacteria and regulates some important H. ducreyi virulence factors. A H. ducreyi cpxR mutant was compared with its parent for virulence in the human challenge model of experimental chancroid. The pustule formation rate in 5 volunteers was 33% (95% confidence interval [CI], 1.3%-65.3%) at 15 parent sites and 40% (95% CI, 18.1%-61.9%) at 15 mutant sites (P = .35). Thus, the cpxR mutant was not attenuated for virulence. Inactivation of the H. ducreyi cpxR gene did not reduce the ability of this mutant to express certain proven virulence factors, including the DsrA serum resistance protein and the LspA2 protein, which inhibits phagocytosis. These results expand our understanding of the involvement of the CpxRA system in regulating virulence expression in H. ducreyi.
    Keywords: Bacterial Proteins -- Genetics ; Chancroid -- Microbiology ; Haemophilus Ducreyi -- Genetics
    ISSN: 00221899
    E-ISSN: 1537-6613
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  • 6
    Language: English
    In: The Journal of infectious diseases, November 2012, Vol.206(9), pp.1407-14
    Description: Haemophilus ducreyi encounters several classes of antimicrobial peptides (APs) in vivo and utilizes the sensitive-to-antimicrobial-peptides (Sap) transporter as one mechanism of AP resistance. A mutant lacking the periplasmic solute-binding component, SapA, was somewhat more sensitive to the cathelicidin LL-37 than the parent strain and was partially attenuated for virulence. The partial attenuation led us to question whether the transporter is fully abrogated in the sapA mutant. We generated a nonpolar sapBC mutant, which lacks both inner membrane permeases of the Sap transporter, and tested the mutant for virulence in human volunteers. In vitro, we compared LL-37 resistance phenotypes of the sapBC and sapA mutants. Unlike the sapA mutant, the sapBC mutant was fully attenuated for virulence in human volunteers. In vitro, the sapBC mutant exhibited significantly greater sensitivity than the sapA mutant to killing by LL-37. Similar to the sapA mutant, the sapBC mutant did not affect H. ducreyi's resistance to human defensins. Compared with the sapA mutant, the sapBC mutant exhibited greater attenuation in vivo, which directly correlated with increased sensitivity to LL-37 in vitro. These results strongly suggest that the SapBC channel retains activity when SapA is removed.
    Keywords: Drug Resistance, Bacterial ; Antimicrobial Cationic Peptides -- Pharmacology ; Haemophilus Ducreyi -- Enzymology ; Membrane Transport Proteins -- Metabolism ; Virulence Factors -- Metabolism
    ISSN: 00221899
    E-ISSN: 1537-6613
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  • 7
    Language: English
    In: Journal of Bacteriology, 2013, Vol.195(15-16), p.3486(17)
    Description: Haemophilus ducreyi causes chancroid, a genital ulcer disease that facilitates the transmission of human immunodeficiency virus type 1. In humans, H. ducreyi is surrounded by phagocytes and must adapt to a hostile environment to survive. To sense and respond to environmental cues, bacteria frequently use two-component signal transduction (2CST) systems. The only obvious 2CST system in H. ducreyi is CpxRA; CpxR is a response regulator, and CpxA is a sensor kinase. Previous studies by Hansen and coworkers showed that CpxR directly represses the expression of dsrA, the lspB-lspA2 operon, and the flp operon, which are required for virulence in humans. They further showed that CpxA functions predominantly as a phosphatase in vitro to maintain the expression of virulence determinants. Since a cpxA mutant is avirulent while a cpxR mutant is fully virulent in humans, CpxA also likely functions predominantly as a phosphatase in vivo. To better understand the role of H. ducreyi CpxRA in controlling virulence determinants, here we defined genes potentially regulated by CpxRA by using RNA-Seq. Activation of CpxR by deletion of cpxA repressed nearly 70% of its targets, including seven established virulence determinants. Inactivation of CpxR by deletion of cpxR differentially regulated few genes and increased the expression of one virulence determinant. We identified a CpxR binding motif that was enriched in downregulated but not upregulated targets. These data reinforce the hypothesis that CpxA phosphatase activity plays a critical role in controlling H. ducreyi virulence in vivo. Characterization of the downregulated genes may offer new insights into pathogenesis.
    Keywords: Chancroid – Causes of ; Gene Expression – Research ; Hemophilus Infections – Research ; Virulence (Microbiology) – Research
    ISSN: 0021-9193
    Source: Cengage Learning, Inc.
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  • 8
    Language: English
    In: 2015, Vol.9(7), p.e0003918
    Description: Although cutaneous ulcers (CU) in the tropics is frequently attributed to Treponema pallidum subspecies pertenue , the causative agent of yaws, Haemophilus ducreyi has emerged as a major cause of CU in yaws-endemic regions of the South Pacific islands and Africa. H . ducreyi is generally susceptible to macrolides, but CU strains persist after mass drug administration of azithromycin for yaws or trachoma. H . ducreyi also causes genital ulcers (GU) and was thought to be exclusively transmitted by microabrasions that occur during sex. In human volunteers, the GU strain 35000HP does not infect intact skin; wounds are required to initiate infection. These data led to several questions: Are CU strains a new variant of H . ducreyi or did they evolve from GU strains? Do CU strains contain additional genes that could allow them to infect intact skin? Are CU strains susceptible to azithromycin? ; To address these questions, we performed whole-genome sequencing and antibiotic susceptibility testing of 5 CU strains obtained from Samoa and Vanuatu and 9 archived class I and class II GU strains. Except for single nucleotide polymorphisms, the CU strains were genetically almost identical to the class I strain 35000HP and had no additional genetic content. Phylogenetic analysis showed that class I and class II strains formed two separate clusters and CU strains evolved from class I strains. Class I strains diverged from class II strains ~1.95 million years ago (mya) and CU strains diverged from the class I strain 35000HP ~0.18 mya. CU and GU strains evolved under similar selection pressures. Like 35000HP, the CU strains were highly susceptible to antibiotics, including azithromycin. ; These data suggest that CU strains are derivatives of class I strains that were not recognized until recently. These findings require confirmation by analysis of CU strains from other regions. ; Cutaneous ulcers (CU) in children living in equatorial Africa and the South Pacific islands have long been attributed to yaws, which is caused by subsp. . However, PCR-based cross sectional surveys done in yaws-endemic regions show that is the leading cause of CU in these regions. . classically causes the genital ulcer (GU) disease chancroid and was once thought to be exclusively sexually transmitted. We show that CU strains obtained from Samoa and Vanuatu are genetically nearly identical to class 1 GU strains and contain no additional genetic content. The CU strains are highly susceptible to antibiotics, including azithromycin. The data suggest an urgent need to obtain and analyze CU isolates from Africa and other countries in the South Pacific and to search for environmental sources of the organism.
    Keywords: Research Article
    ISSN: 19352727
    E-ISSN: 1935-2735
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  • 9
    Language: English
    In: Houinei, W., C. Godornes, A. Kapa, S. Knauf, E. Q. Mooring, C. González-Beiras, R. Watup, et al. 2017. “Haemophilus ducreyi DNA is detectable on the skin of asymptomatic children, flies and fomites in villages of Papua New Guinea.” PLoS Neglected Tropical Diseases 11 (5): e0004958. doi:10.1371/journal.pntd.0004958. http://dx.doi.org/10.1371/journal.pntd.0004958.
    Description: Background: Haemophilus ducreyi and Treponema pallidum subsp. pertenue are major causes of leg ulcers in children in Africa and the Pacific Region. We investigated the presence of DNA (PCR positivity) from these bacteria on asymptomatic people, flies, and household linens in an endemic setting. Methodology/Principal findings We performed a cross-sectional study in rural villages of Lihir Island, Papua New Guinea during a yaws elimination campaign. Participants were asymptomatic subjects recruited from households with cases of leg ulcers, and from households without cases of leg ulcers. We rubbed swabs on the intact skin of the leg of asymptomatic individuals, and collected flies and swabs of environmental surfaces. All specimens were tested by PCR for H. ducreyi and T. p. pertenue DNA. Of 78 asymptomatic participants that had an adequate specimen for DNA detection, H. ducreyi-PCR positivity was identified in 16 (21%) and T. p. pertenue-PCR positivity in 1 (1%). In subgroup analyses, H. ducreyi-PCR positivity did not differ in participants exposed or not exposed to a case of H. ducreyi ulcer in the household (24% vs 18%; p = 0.76). Of 17 cultures obtained from asymptomatic participants, 2 (12%) yielded a definitive diagnosis of H. ducreyi, proving skin colonization. Of 10 flies tested, 9 (90%) had H. ducreyi DNA and 5 (50%) had T. p. pertenue DNA. Of 6 bed sheets sampled, 2 (33%) had H. ducreyi DNA and 1 (17%) had T. p. pertenue DNA. Conclusions/Significance: This is the first time that H. ducreyi DNA and colonization has been demonstrated on the skin of asymptomatic children and that H. ducreyi DNA and T. p. pertenue DNA has been identified in flies and on fomites. The ubiquity of H. ducreyi in the environment is a contributing factor to the spread of the organism.
    Keywords: Medicine And Health Sciences ; Diagnostic Medicine ; Signs And Symptoms ; Ulcers ; Pathology And Laboratory Medicine ; Biology And Life Sciences ; Molecular Biology ; Molecular Biology Techniques ; Artificial Gene Amplification And Extension ; Polymerase Chain Reaction ; Infectious Diseases ; Bacterial Diseases ; Treponematoses ; Yaws ; Tropical Diseases ; Neglected Tropical Diseases ; Dermatology ; Skin Infections ; Microbiology ; Medical Microbiology ; Microbial Pathogens ; Bacterial Pathogens ; Treponema Pallidum ; Pathogens ; Bacteriology ; Gram Negative Bacteria ; Extraction Techniques ; Dna Extraction ; Organisms ; Bacteria ; Haemophilus
    ISSN: 19352727
    E-ISSN: 19352735
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  • 10
    Language: English
    In: Journal of Infectious Diseases, 2016, Vol.214(3), pp.489-495
    Keywords: Haemophilus Ducreyi ; Chancroid ; Skin Ulcers ; Immunogenetics ; Humans ; Innate Immunity
    ISSN: 0022-1899
    ISSN: 1537-6613
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