bluuebunny/crossref_metadata_2025_split huggingface dataset:
Telithromycin Susceptibility and Genomic Diversity of Macrolide-Resistant Serotype III Group B Streptococci Isolated in Perinatal Infections
Authors: Bingen Edouard , Doit Catherine , Bidet Philippe , Brahimi Naima , Deforche Dominique 
Published: January 2004

ABSTRACT

We studied the telithromycin, erythromycin, azithromycin, and clindamycin susceptibilities of serotype III macrolide-resistant group B streptococci, together with genetic mechanisms of resistance and genomic diversity.
ermB
,
ermA
, and
mefA
were found in, respectively, 57, 32, and 9% of isolates. The telithromycin MIC at which 90% of isolates were inhibited was 0.5 μg/ml. Macrolide resistance was associated with dissemination of resistance determinants among isolates of different genetic backgrounds.
The Ferritin-Like Dps Protein Is Required for
Salmonella enterica
Serovar Typhimurium Oxidative Stress Resistance and Virulence
Authors: Halsey Thomas A. , Vazquez-Torres Andrés , Gravdahl Daniel J. , Fang Ferric C. , Libby Stephen J. 
Published: January 2004

ABSTRACT

Resistance to phagocyte-derived reactive oxygen species is essential for
Salmonella enterica
serovar Typhimurium pathogenesis.
Salmonella
can enhance its resistance to oxidants through the induction of specific genetic pathways controlled by SoxRS, OxyR, σ
S
, σ
E
, SlyA, and RecA. These regulons can be found in a wide variety of pathogenic and environmental bacteria, suggesting that evolutionarily conserved mechanisms defend against oxidative stress both endogenously generated by aerobic respiration and exogenously produced by host phagocytic cells. Dps, a ferritin-like protein found in many eubacterial and archaebacterial species, appears to protect cells from oxidative stress by sequestering iron and limiting Fenton-catalyzed oxyradical formation. In
Escherichia coli
and some other bacterial species, Dps has been shown to accumulate during stationary phase in a σ
S
-dependent fashion, bind nonspecifically to DNA, and form a crystalline structure that compacts and protects chromatin from oxidative damage. In the present study, we provide evidence that Dps protects
Salmonella
from iron-dependent killing by hydrogen peroxide, promotes
Salmonella
survival in murine macrophages, and enhances
Salmonella
virulence. Reduced numbers of
dps
mutant bacteria in the livers and spleens of infected mice are consistent with a role of Dps in protecting
Salmonella
from oxidative stress encountered during infection.
A K
+
Uptake Protein, TrkA, Is Required for Serum, Protamine, and Polymyxin B Resistance in
Vibrio vulnificus
Authors: Chen Yu-Chung , Chuang Yin-Ching , Chang Chun-Chin , Jeang Chii-Ling , Chang Ming-Chung 
Published: January 2004

ABSTRACT

Vibrio vulnificus
, a highly virulent marine bacterium, is the causative agent of both serious wound infections and fatal septicemia in many areas of the world. To identify the genes required for resistance to human serum, we constructed a library of transposon mutants of
V. vulnificus
and screened them for hypersensitivity to human serum. Here we report that one of the isolated serum-susceptible mutants had a mutation in an open reading frame identified as
trkA
, a gene encoding an amino acid sequence showing high identity to that of TrkA of
Vibrio alginolyticus
, a protein required for the uptake of potassium. A
trkA
isogenic mutant was constructed via insertional inactivation, and it was significantly more easily killed by human serum, protamine, or polymyxin B than was the wild type. At K
+
concentrations of 1 to 20 mM, this isogenic mutant showed attenuated growth compared to the wild-type strain. In addition, infection experiments demonstrated virulence attenuation when this mutant was administered intraperitoneally or subcutaneously to both normal and iron-treated mice, indicating that TrkA may modulate the transport of potassium and resistance to host innate defenses and that it is important for virulence in mice.
Sequence Analysis ofp44Homologs Expressed byAnaplasma phagocytophilumin Infected Ticks Feeding on Naive Hosts and in Mice Infected by Tick Attachment
Authors: Felek Suleyman , Telford Sam , Falco Richard C. , Rikihisa Yasuko 
Published: January 2004

ABSTRACTThe 44-kDa immunodominant outer membrane proteins (P44 proteins) ofAnaplasma phagocytophilumare encoded by thep44polymorphic multigene family. The present study examinedp44expression and analyzed the cDNA sequences of variousp44transcripts from the spleens and blood of mice infected by the bites of ticks infected with theA. phagocytophilumNTN-1 strain or of naturally infected nymphal ticks and in the salivary glands and midgut tissues of these ticks. A total of 300p44cDNAs were subjected to sequence analysis. Of these, 40 distinctp44species were found, and all of these had orthologs in theA. phagocytophilumHZ strain genome that shared 95 to 100% base sequence identity. The number of uniquep44species expressed in mouse blood was greater than that for mouse spleens. Higher numbers of differentp44transcripts were also expressed in the salivary glands of ticks than in the midgut tissues. Variations in the sequences of the samep44cDNA species within a singleA. phagocytophilumstrain and among different strains were concentrated in the conserved regions flanking the central hypervariable region ofp44genes. No mosaic sequences derived from two or morep44species were found within thep44hypervariable region. The conservation of the hypervariable region of eachp44cDNA species ofA. phagocytophilumin naturally infected ticks and in different geographic isolates suggests that eachA. phagocytophilumgenome carries a set ofp44paralogs to be expressed. Thus, a large but restricted repertoire ofp44hypervariable sequences exists inA. phagocytophilumstrains in the Northeastern United States.
Expression of Amoebapores Is Required for Full Expression ofEntamoeba histolyticaVirulence in Amebic Liver Abscess but Is Not Necessary for the Induction of Inflammation or Tissue Damage in Amebic Colitis
Authors: Zhang Xiaochun , Zhang Zhi , Alexander Diane , Bracha Rivka , Mirelman David , Stanley Samuel L. 
Published: January 2004

ABSTRACTEntamoeba histolyticatrophozoites produce amoebapores, a family of small amphipathic peptides capable of insertion into bacterial or eukaryotic membranes and causing cellular lysis. Recently,E. histolyticatrophozoites that are totally deficient in the production of amoebapore-A were created through a gene silencing mechanism (R. Bracha, Y. Nuchamowitz, and D. Mirelman, Eukaryot. Cell 2:295-305, 2003). Here we tested the virulence of amoebapore A(−) trophozoites in models of the two major forms of amebic disease: amebic liver abscess and amebic colitis. We demonstrate that amoebapore expression is required for full virulence in the SCID mouse model of amebic liver abscess, butE. histolyticatrophozoites that do not express amoebapore-A can still cause inflammation and tissue damage in infected human colonic xenografts. These data are consistent with the concept that tissue damage may proceed by different mechanisms in amebic liver abscess compared to amebic colitis.
Sensitized Splenocytes Result in Deleterious Cytokine Cascade and Hyperinflammatory Response in Rats withPneumocystisPneumonia despite the Presence of Corticosteroids
Authors: Thullen Timothy D. , Ashbaugh Alan D. , Daly Kieran R. , Linke Michael J. , Steele Paul E. , Walzer Peter D. 
Published: January 2004

ABSTRACTThe immune response to the opportunistic pulmonary pathogenPneumocystiscan have beneficial and harmful effects on the host despite the presence of corticosteroids. We hypothesized that this deleterious hyperinflammatory response is associated with exaggerated cytokine production. The adoptive transfer of at least 107immune splenocytes reduced the cyst count in rats with corticosteroid-induced pneumocystosis. About 18% of these rats developed clinical illness, an increased lung weight/body weight (LW/BW) ratio, and elevated levels of interleukin 1α (IL-1α), IL-1β, IL-6, tumor necrosis factor alpha, IL-5, IL-10, and gamma interferon in the lungs. This hyperinflammatory reaction was not observed in rats that remained clinically well or in control rats. Thus, in this model, corticosteroids have little effect on the cytokine cascade or other adverse effects of the host immune response toPneumocystis.
Investigation of a Novel DNase of
Streptococcus suis
Serotype 2
Authors: Fontaine Michael C. , Perez-Casal Jose , Willson Philip J. 
Published: January 2004

ABSTRACT

A secreted nuclease, SsnA, was identified in the virulent
Streptococcus suis
isolate SX332 and subsequently in each of the type strains of capsular serotypes 1 through 9. Screening of 258 porcine clinical isolates from surface (nasal mucosa or palatine tonsil) or internal (joint, brain or other internal organ) locations revealed a significant relationship (
P
< 0.001) between expression of nuclease and isolation from an internal site. A 3,126-bp gene,
ssnA
, was identified from a phenotypically nuclease-negative pGh9:IS
S1
insertion mutant, and analysis of the predicted SsnA sequence revealed a 35-amino-acid (aa) secretion signal sequence, a 22-aa DNA-binding domain, and a typical gram-positive cell wall sorting motif. A requirement of Ca
2+
and Mg
2+
for SsnA activity was determined, and the substrate specificity was found to be for single- and double-stranded linear DNA. Reverse transcription-PCR experiments revealed that
ssnA
is expressed throughout all stages of
S. suis
growth, and Western blots with porcine anti-
S. suis
immune sera against a recombinant, truncated SsnA derivative (rSsnA
Δ
) confirmed that SsnA is expressed in vivo. Furthermore, anti-rSsnA
Δ
antibodies were sufficient to neutralize SsnA activity. Analyses of subcellular fractions of SX332 and derived mutants, on DNA-containing polyacrylamide gels and by Western blotting, suggest that SsnA is cell wall located.
Salivary Statherin Peptide-Binding Epitopes of Commensal and Potentially Infectious
Actinomyces
spp. Delineated by a Hybrid Peptide Construct
Authors: Niemi Liza Danielsson , Johansson Ingegerd 
Published: January 2004

ABSTRACT

Adhesion of microorganisms to host receptor molecules such as salivary statherin molecules is a common event in oral microbial colonization. Here we used a hybrid peptide construct (with both a hydroxyapatite-binding portion and a test peptide portion) to map the interaction of
Actinomyces
species (and
Candida albicans
) with statherin. Adhesion to hybrid peptides and truncated statherin variants revealed three binding types, types I to III. (i) Type I strains of rat, hamster, and human infection origins bound C-terminal-derived QQYTF and PYQPQY peptides. The QQYTF peptide inhibited statherin binding for some strains but not for others. (ii) Type II strains of human and monkey tooth origins bound middle-region-derived YQPVPE and QPLYPQ peptides. Neither strain was inhibited by soluble peptides. (iii) Type III strains of human infection origins (and
C. albicans
) did not bind to either statherin-derived peptides or truncated statherin. Moreover, the type I strains inhibited by QQYTF were also inhibited by TF and QAATF peptides and were detached from statherin by the same peptides. In conclusion, it is suggested that commensal and potentially infectious microorganisms bind middle or C-terminal statherin differently and that other microbes might require discontinuous epitopes.
Role of theSalmonellaPathogenicity Island 1 Effector Proteins SipA, SopB, SopE, and SopE2 inSalmonella entericaSubspecies 1 Serovar Typhimurium Colitis in Streptomycin-Pretreated Mice
Authors: Hapfelmeier Siegfried , Ehrbar Kristin , Stecher Bärbel , Barthel Manja , Kremer Marcus , Hardt Wolf-Dietrich 
Published: January 2004

ABSTRACTSalmonella entericasubspecies 1 serovar Typhimurium (serovar Typhimurium) induces enterocolitis in humans and cattle. The mechanisms of enteric salmonellosis have been studied most extensively in calf infection models. The previous studies established that effector protein translocation into host cells via theSalmonellapathogenicity island 1 (SPI-1) type III secretion system (TTSS) is of central importance in serovar Typhimurium enterocolitis. We recently found that orally streptomycin-pretreated mice provide an alternative model for serovar Typhimurium colitis. In this model the SPI-1 TTSS also plays a key role in the elicitation of intestinal inflammation. However, whether intestinal inflammation in calves and intestinal inflammation in streptomycin-pretreated mice are induced by the same SPI-1 effector proteins is still unclear. Therefore, we analyzed the role of the SPI-1 effector proteins SopB/SigD, SopE, SopE2, and SipA/SspA in elicitation of intestinal inflammation in the murine model. We found thatsipA,sopE, and, to a lesser degree,sopE2contribute to murine colitis, but we could not assign an inflammation phenotype tosopB. These findings are in line with previous studies performed with orally infected calves. Extending these observations, we demonstrated that in addition to SipA, SopE and SopE2 can induce intestinal inflammation independent of each other and in the absence of SopB. In conclusion, our data corroborate the finding that streptomycin-pretreated mice provide a useful model for studying the molecular mechanisms of serovar Typhimurium colitis and are an important starting point for analysis of the molecular events triggered by SopE, SopE2, and SipA in vivo.
Characterization of Immunoglobulin G and Its Subclass Response to Indian Kala-Azar Infection before and after Chemotherapy
Authors: Ravindran Rajesh , Anam Khairul , Bairagi Bibhas C. , Saha Bibhuti , Pramanik Netai , Guha Subhasis K. , Goswami Rama P. , Banerjee Dwijadas , Ali Nahid 
Published: January 2004

ABSTRACTSerologic parameters of kala-azar were evaluated by Western blot analysis. Sera from kala-azar patients with confirmed diagnoses were screened for immunoglobulin G (IgG) and IgG subclass-specific reactivity againstLeishmania donovanimembrane antigen (LAg). Heterogenous LAg-specific IgG reactivity with numerous proteins with molecular masses ranging from 18 to 190 kDa was observed. Though the individual band patterns were varied, seven polypeptides of approximately 31, 34, 51, 63, 72, 91, and 120 kDa were immunoreactive with all the sera tested from kala-azar patients. The band patterns of the immunoblots of sera from patients after treatment and clinical cure with sodium antimony gluconate revealed a decrease in the frequency of the bands. Still, recognition of the 63- and 120-kDa bands was 100%, and the 55- and 91-kDa fractions were recognized in 93% of the sera from cured individuals. Among the IgG subclasses, IgG1 reacted with the greatest number of polypeptides. The 63-kDa protein was again detected by all of the IgG subclasses of all the sera tested. Other fractions recognized by the subclasses of more than 70% of the serum samples included those of 47, 51, 55, and 78 kDa. Following treatment, 63- and 51-kDa bands were the most reactive with the IgG subclasses. LAg-associated cross-reaction with other reference human antisera revealed a mild reactivity of the 63-kDa polypeptide with some of the serum samples from leprosy, malaria, typhoid, tuberculosis, and healthy controls. Western blot analysis of LAg entrapped in liposomes, strong vaccine candidates against experimental visceral leishmaniasis, revealed a more restricted band pattern. The 63-kDa fraction revealed by all pre- and posttreatment sera showed almost negligible levels of cross-reaction with sera from patients with other diseases or from healthy controls. These observations provide insight into induced immunity during kala-azar infection for future application.
CpG Oligodeoxynucleotide and Montanide ISA 51 Adjuvant Combination Enhanced the Protective Efficacy of a Subunit Malaria Vaccine
Authors: Kumar Sanjai , Jones Trevor R. , Oakley Miranda S. , Zheng Hong , Kuppusamy Shanmuga P. , Taye Alem , Krieg Arthur M. , Stowers Anthony W. , Kaslow David C. , Hoffman Stephen L. 
Published: January 2004

ABSTRACTUnmethylated CpG dinucleotide motifs present in bacterial genomes or synthetic oligodeoxynucleotides (ODNs) serve as strong immunostimulatory agents in mice, monkeys and humans. We determined the adjuvant effect of murine CpG ODN 1826 on the immunogenicity and protective efficacy of theSaccharomyces cerevisiae-expressed 19-kDa C-terminal region of merozoite surface protein 1 (yMSP119) of the murine malaria parasitePlasmodium yoelii. We found that in C57BL/6 mice, following sporozoite challenge, the degree of protective immunity against malaria induced by yMSP119in a formulation of Montanide ISA 51 (ISA) plus CpG ODN 1826 was similar or superior to that conferred by yMSP119emulsified in complete Freund's adjuvant (CFA/incomplete Freund's adjuvant). In total, among mice immunized with yMSP119, 22 of 32 (68.7%) with ISA plus CpG 1826, 0 of 4 (0%) with CFA/incomplete Freund’s adjuvant, 0 of 4 (0%) with CpG 1826 mixed with ISA (no yMSP119), and 0 of 11 (0%) with CpG 1826 alone were completely protected against development of erythrocytic stage infection after sporozoite challenge. The adjuvant effect of CpG ODN 1826 was manifested as both significantly improved complete protection from malaria (defined as the absence of detectable erythrocytic form parasites) (P= 0.007, chi square) and reduced parasite burden in infected mice. In vivo depletions of interleukin-12 and gamma interferon cytokines and CD4+and CD8+T cells in vaccinated mice had no significant effect on immunity. On the other hand, immunoglobulin G (IgG) isotype levels appeared to correlate with protection. Inclusion of CpG ODN 1826 in the yMSP119plus ISA vaccine contributed towards the induction of higher levels of IgG2a and IgG2b (Th1 type) antibodies, suggesting that CpG ODN 1826 caused a shift towards a Th1 type of immune response that could be responsible for the higher degree of protective immunity. Our results indicate that this potent adjuvant formulation should be further evaluated for use in clinical trials of recombinant malarial vaccine candidates.
Differential Production of Systemic and Intralesional Gamma Interferon and Interleukin-10 in Nodular and Ulcerative Forms of Buruli Disease
Authors: Prévot Ghislaine , Bourreau Eliane , Pascalis Herve , Pradinaud Roger , Tanghe Audrey , Huygen Kris , Launois Pascal 
Published: January 2004

ABSTRACTBuruli disease, caused byMycobacterium ulcerans, is the third most important mycobacterial disease in humans besides tuberculosis and leprosy. We have compared systemic and intralesional cytokine production in patients presenting with a nodular form and a necrotizing, ulcerative form of the disease. Gamma interferon (IFN-γ) levels in response to wholeM. ulceransandMycobacterium bovisBCG bacilli and in response to purified Ag85 protein from BCG were lower in peripheral blood mononuclear cells (PBMC) cultures from Buruli disease patients than in PBMC from healthy purified protein derivative-positive contacts. Interleukin-4 (IL-4) and IL-13 content was below the detection threshold in these PBMC cultures. IFN-γ production after stimulation withM. ulceranswas significantly lower (P< 0.05) in PBMC cultures from patients with ulcers than in those from patients with nodules. On the other hand, PBMC from Buruli disease patients produced significant levels of IL-10 in response toM. ulcerans(but not toM. bovisBCG) and production was highest in patients with the ulcerative form. Third, semiquantitative reverse transcription-PCR analysis demonstrated a similar difference in the local, intralesional cytokine profile for the two forms of the disease: high IFN-γ but low IL-10 mRNA levels in nodular lesions and high IL-10 but low IFN-γ mRNA levels in ulcerative lesions. Intralesional IL-4 and IL-13 mRNA levels were low and only detected in patients with the ulcerative form. Our results indicate, although they do not formally prove, that production of IL-10 rather than production of IL-4 or IL-13 by Th2-type T cells may be involved in the lowM. ulcerans-specific IFN-γ response in Buruli disease patients.
Willem Heda and the edition of his Historia episcoporum Ultrajectensium
Authors: Van Der Horst Koert 
Published: January 2004

AbstractWhen Willem Heda concluded his Latin history of the Utrecht bishops on 1 May 1521 with a dedicatory epistle to the Utrecht Cathedral Chapter, he probably could not have expected it would take almost a century before the work was actually printed. That he assumed his history would soon be on the press is apparent from a sentence in the dedication itself: '. . . iussistis ut . . . etiam gesta ac vitas sanctorum, . . . ea in lucem proferentes publicis impensis novis formis excudenda traderemus, . . . [You, canons of the cathedral, commissioned us . . . to publish also the history and lives of the saints (the bishops of Utrecht) and present it to be printed at your expense (at the expense of public funds), "novis formis": in the new letters (type faces)]'.
N-acetylcysteine decreases lactate signal intensities in liver tissue and improves liver function in septic shock patients, as shown by magnetic resonance spectroscopy: extended case report
Authors: Hein Ortrud Vargas , Öhring Renate , Schilling Andreas , Oellerich Michael , Armstrong Victor W , Kox Wolfgang J , Spies Claudia 
Published: January 2004

Abstract
Background
N-acetylcysteine (NAC) has been shown to improve splanchnic blood flow in experimental studies. This report evaluates the effects of NAC on liver perfusion and lactate signal intensities in the liver tissue of septic shock patients using proton magnetic resonance imaging and spectroscopy. Furthermore, the monoethylglycinexylidide (MEGX) test was used to investigate hepatic function.

Methods
Five septic shock patients received 150 mg/kg body weight NAC as an intravenous bolus injection over 15 min. Lidocaine was injected both prior to and following NAC administration in order to determine MEGX formation. Measurements (hemodynamics, oxygen transport-related variables, blood samples for lactate, liver-related markers) were performed 1 hour before and 1 hour after NAC injection. In addition to the proton magnetic resonance imaging patients received two proton magnetic resonance spectra, one prior to and one 30 min subsequent to the onset of the NAC infusion at a 1.5 Tesla clinical scanner, for measurement of liver perfusion and liver lactate signal intensity.

Main findings
Following NAC infusion, the lactate signal intensity in the liver tissue showed a median decrease of 89% (11–99%), there was a median increase in liver perfusion of 41% (-14 to 559%), and the MEGX serum concentration increased three times (1.52–5.91).

Conclusions
A decrease in the lactate signal intensity in the liver tissue and an increase in the MEGX serum concentration and in liver perfusion might indicate improved liver function as a result of NAC administration. Patients with compromised hepatosplanchnic function, such as patients with septic shock due to peritonitis, may therefore benefit from NAC therapy.