bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Anthracnose of Salal Caused by Colletotrichum acutatum in British Columbia
Authors: Elmhirst J. F. , Verma N. 
Published: December 2007

Gaultheria shallon Pursh (salal) is a native, Pacific Northwest forest understory plant produced by numerous commercial nurseries as a garden and landscape ground cover. Seed is sown in soilless media in greenhouse plug flats, and seedlings are transplanted into larger pots at 24 to 36 weeks. In October 2005, approximately 30% of 16-week-old G. shallon Pursh (salal) seedlings in a commercial greenhouse in coastal British Columbia, Canada were observed to be dying back. Black, water-soaked, cankers girdled the stems and petioles resulting in seedling necrosis. Cankers extended into the base of affected leaves, and irregular, black leaf spots with concentric rings were observed. A Colletotrichum sp. was isolated on potato dextrose agar (PDA) + 0.005% streptomycin. In May 2006, 160 20-week-old salal seedlings (two- to five-leaf stage) in four plug cell flats of 40 seedlings each were inoculated with a hand atomizer with a mycelial and spore suspension of approximately 1 × 108 CFU/ml (dilution plating) in 100 mL sterile dH2O; 120 seedlings (four flats of 30 seedlings each) were sprayed with water alone. Flats were covered with black plastic for 48 h and then placed randomly in a shaded greenhouse at 14 to 22°C with overhead watering. The percentage of necrotic seedlings with black, water-soaked cankers and leaf spots in the inoculated flats at 1 to 8 weeks was 3.8, 7.6, 8.2, 16.4, 44.9, 62.0, 79.7, and 81.6, consecutively; versus 2.5% at 8 weeks in the noninoculated flats. Infection of the noninoculated seedlings was presumably due to spore splash from irrigation. Both the original isolate used as inoculum and colonies reisolated on PDA from inoculated, surface-sterilized, symptomatic tissues were identified as Colletotrichum acutatum J.H. Simmonds based on morphology (2) and PCR using a species-specific primer (1). Hyaline, aseptate, fusiform conidia, measuring 8 to 16 × 2.5 to 4 μm, were produced in acervuli without setae on plants and in culture. The teleomorph (Glomerella) stage was not observed. To our knowledge, this is the first report of an anthracnose disease of salal. References: (1) S. Freeman et al. Plant Dis. 82:596, 1998. (2) J. E. M. Mordue. No. 315 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1971.
First Report of Powdery Mildew on Pyrus calleryana Caused by Podosphaera leucotricha
Authors: Vajna L. , Kiss L. 
Published: December 2007

Callery pear (Pyrus calleryana Decne.) is native to Asia and its varieties are planted as ornamentals in urban areas worldwide. It is also used as a source of resistance to fireblight in some breeding programs. In April 2007, symptoms of powdery mildew infection were observed on the foliage of almost every P. calleryana cv. Chanticleer tree planted along a 1.5-km road in Budapest, Hungary. These trees were planted 5 to 6 years ago and were the first callery pears used as ornamentals in Hungary. Powdery mildew infections were also detected on P. calleryana trees planted in other parts of the city. White powdery mildew mycelium appeared on the lower and sometimes upper leaf surfaces, especially on young shoots, and caused chlorotic spots on the upper leaf surfaces and severe distortions of leaves. The spread of the infection was monitored between April and August of 2007 in several sample sites. More than 100 trees that were examined became heavily infected by May 2007. Powdery mildew conidiophores were typical of the genus Oidium subgen. Fibroidium, the anamorph of the teleomorph genus Podosphaera (2). Conidia developed in chains, contained fibrosin bodies, germinated at one of their ends with germ tubes terminating in unlobed appressoria, and measured 16 to 27 × 10 to 15 μm. Hyphal appressoria were nipple shaped or inconspicuous. The teleomorph was not found. To precisely identify the pathogen, DNA was extracted from conidia collected with a sterile brush from a single leaf using a Qiagen DNeasy Plant Kit (Hilden, Germany), and the internal transcribed spacer (ITS) sequence of the ribosomal DNA was amplified and determined as described by Szentiványi et al. (3). The ITS sequence, deposited in GenBank under Accession No. EU148597, was identical to those determined in Podosphaera leucotricha (Ell. & Ev.) Salmon collected from apple in Australia (GenBank Accession No. AF073353) and Canada (GenBank Accession No. AY157844) and also from pear in Canada (GenBank Accession No. AY157845). Thus, the pathogen was identified as Podosphaera leucotricha on the basis of the host genus, morphology of the anamorph, and ITS sequence. Specimens were deposited under Accession No. BPI878262 at the U.S. National Fungus Collection. To our knowledge, Podosphaera leucotricha has not been reported on P. calleryana in any parts of the world so far. An Oidium sp. infecting this plant in Australia was listed by Amano (1), but the exact identity of that fungus is not known. Thus, this is the first report of an identified powdery mildew fungus on P. calleryana. References: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Societies Press, Tokyo, 1986. (2) U. Braun et al. Pages 13-55 in: The Powdery Mildews: A Comprehensive Treatise. R. R Bélanger et al., eds. American Phytopathological Society, St Paul, MN, 2002. (3) O. Szentiványi et al. Mycol. Res. 109:429, 2005.
Molecular Basis for Resistance of
Acanthamoeba
Tubulins to All Major Classes of Antitubulin Compounds
Authors: Henriquez Fiona L. , Ingram Paul R. , Muench Stephen P. , Rice David W. , Roberts Craig W. 
Published: December 2007

ABSTRACT

Tubulin is essential to eukaryotic cells and is targeted by several antineoplastics, herbicides, and antimicrobials. We demonstrate that
Acanthamoeba
spp. are resistant to five antimicrotubule compounds, unlike any other eukaryote studied so far. Resistance correlates with critical amino acid differences within the inhibitor binding sites of the tubulin heterodimers.
Thiopurine Drugs Azathioprine and 6-Mercaptopurine Inhibit
Mycobacterium paratuberculosis
Growth In Vitro
Authors: Shin Sung Jae , Collins Michael T. 
Published: December 2007

ABSTRACT

The in vitro susceptibility of human- and bovine-origin
Mycobacterium paratuberculosis
to the thioupurine drugs 6-mercaptopurine (6-MP) and azathioprine (AZA) was established using conventional plate counting methods and the MGIT 960 ParaTB culture system. Both 6-MP and AZA had antibacterial activity against
M. paratuberculosis
; isolates from Crohn's disease patients tended to be more susceptible than were bovine-origin isolates. Isolates of
Mycobacterium avium
, used as controls, were generally resistant to both AZA and 6-MP, even at high concentrations (≥64.0 μg/ml). Among rapidly growing mycobacteria,
Mycobacterium phlei
was susceptible to 6-MP and AZA whereas
Mycobacterium smegmatis
strains were not. AZA and 6-MP limited the growth of, but did not kill,
M. paratuberculosis
in a dose-dependent manner. Anti-inflammatory drugs in the sulfonamide family (sulfapyridine, sulfasalazine, and 5-aminosalycilic acid [mesalamine]) had little or no antibacterial activity against
M. paratuberculosis
. The conventional antibiotics azithromycin and ciprofloxacin, used as control drugs, were bactericidal for
M. paratuberculosis
, exerting their killing effects on the organism relatively quickly. Simultaneous exposure of
M. paratuberculosis
to 6-MP and ciprofloxacin resulted in significantly higher CFU than use of ciprofloxacin alone. These data may partially explain the paradoxical response of Crohn's disease patients infected with
M. paratuberculosis
to treatment with immunosuppressive thiopurine drugs, i.e., they do not worsen with anti-inflammatory treatment as would be expected with a microbiological etiologic pathogen. These findings also should influence the design of therapeutic trials to evaluate antibiotic treatments of Crohn's disease: AZA drugs may confound interpretation of data on therapeutic responses for both antibiotic-treated and control groups.
Hepatotoxicity Observed in Clinical Trials of Aplaviroc (GW873140)
Authors: Nichols W. G. , Steel H. M. , Bonny T. , Adkison K. , Curtis L. , Millard J. , Kabeya K. , Clumeck N. 
Published: December 2007

ABSTRACT
Aplaviroc (APL) was a new CCR5 antagonist that was investigated in two dose-ranging studies with antiretroviral therapy-naïve, human immunodeficiency virus-infected adults: ASCENT, in which 147 subjects were randomized 2:2:1 to receive zidovudine-lamivudine (ZDV-3TC) plus APL 600 mg twice a day (BID), APL 800 mg BID, or efavirenz (EFV), respectively, and EPIC, in which 195 subjects were randomized 2:2:2:1 to receive lopinavir-ritonavir (LPV-RTV) plus APL 200 mg BID, APL 400 mg BID, APL 800 mg once a day, or ZDV-3TC BID, respectively. Both studies (and, ultimately, the clinical development of APL) were discontinued after a mean of 14 weeks of therapy because of higher than anticipated severe liver toxicity; grade 2 or higher treatment-emergent elevations in alanine aminotransferase (ALT) levels were observed in 17/281 (6.0%) APL recipients but only 2/55 (3.6%) control recipients, while grade 2 or higher elevations in total bilirubin levels occurred in 29/281 (10.3%) APL recipients but only 4/55 (7.3%) controls. Two APL recipients developed grade 3 or higher treatment-emergent elevations in both ALT and total bilirubin levels, and one of these individuals had a severe case of hepatic cytolysis that was attributed to APL. Despite the high intersubject variability in APL plasma exposures, a Pearson correlation analysis of the combined study data did not reveal any significant associations between plasma concentrations and the liver enzyme elevations observed during the study. The mechanism for the idiosyncratic hepatotoxicity observed in the clinical trials of APL is unknown but is likely intrinsic to the molecule rather than its novel mechanism of action.
Combined Real-Time PCR and Pyrosequencing Strategy for Objective, Sensitive, Specific, and High-Throughput Identification of Reduced Susceptibility to Penicillins in
Neisseria meningitidis
Authors: Thulin Sara , Olcén Per , Fredlund Hans , Unemo Magnus 
Published: December 2007

ABSTRACT

A segment of
penA
in
Neisseria meningitidis
strains (
n
= 127), including two nucleotide sites closely associated to reduced susceptibility to penicillins, was amplified and pyrosequenced. All results were in concordance with Sanger sequencing, and a high correlation between alterations in the two Pen
i
-specific sites and reduced susceptibility to penicillins was identified.
Tetracycline Resistance Gene
tet
(W) in the Pathogenic Bacterium
Clostridium difficile
Authors: Spigaglia Patrizia , Barbanti Fabrizio , Mastrantonio Paola 
Published: December 2007

ABSTRACT

In this study, the
tet
(W) gene region of a human clinical isolate of
Clostridium difficile
resistant to tetracycline was characterized. This gene was a new allele showing 99% sequence identity to the gene found in the human strain
Bifidobacterium longum
F8, and it is not transferable by “in vitro” mating experiments.
Calcineurin Inhibitor Agents Interact Synergistically with Antifungal Agents In Vitro against
Cryptococcus neoformans
Isolates: Correlation with Outcome in Solid Organ Transplant Recipients with Cryptococcosis
Authors: Kontoyiannis Dimitrios P. , Lewis Russell E. , Alexander Barbara D. , Lortholary Olivier , Dromer Françoise , Gupta Krishan L. , John George T. , del Busto Ramon , Klintmalm Goran B. , Somani Jyoti , Lyon G. Marshall , Pursell Kenneth , Stosor Valentina , Muňoz Patricia , Limaye Ajit P. , Kalil Andre C. , Pruett Timothy L. , Garcia-Diaz Julia , Humar Atul , Houston Sally , House Andrew A. , Wray Dannah , Orloff Susan , Dowdy Lorraine A. , Fisher Robert A. , Heitman Joseph , Albert Nathaniel D. , Wagener Marilyn M. , Singh Nina 
Published: December 2007

ABSTRACT

Synergistic interactions were observed between CIs and antifungal agents against 53 (90%) of 59
Cryptococcus neoformans
isolates from solid organ transplant recipients with cryptococcosis and may account for better outcomes in patients with cryptococcosis receiving these immunosuppressive agents.
Azurin-Like Protein Blocks Invasion ofToxoplasma gondiithrough Potential Interactions with Parasite Surface Antigen SAG1
Authors: Naguleswaran Arunasalam , Fialho Arsenio M. , Chaudhari Anita , Hong Chang Soo , Chakrabarty Ananda M. , Sullivan William J. 
Published: December 2007

ABSTRACTSome pathogenic bacteria produce factors that have evolved a capacity to neutralize competing microbes. The cupredoxin family protein azurin, produced byPseudomonas aeruginosa, exhibits a remarkable ability to impede invasion of a number of diverse intracellular pathogens, including the human AIDS virus human immunodeficiency virus type 1 and the protozoan parasitePlasmodium falciparum(which causes malaria). Here we report that azurin and an azurin-like protein (Laz) from gonococci/meningococci have activity againstToxoplasma, an apicomplexan parasite that causes opportunistic infection in immunocompromised individuals. We demonstrate that the mechanism of action for Laz involves interfering with the ability ofToxoplasmato adhere to host cells. Computer structural analysis reveals that azurin shares structural features with the predominant surface antigen SAG1, which is known to play an important role in parasite attachment. Interestingly, azurin also has structural similarities to a monoclonal antibody to SAG1. Surface plasmon resonance binding studies validate that SAG1 interacts strongly with Laz and, to lesser extent, azurin. Moreover,Toxoplasmamutants lacking SAG1 are not as susceptible to the growth-inhibitory effects of Laz. Collectively, our data show thatToxoplasmaadhesion can be significantly impaired by Laz, and to some extent by azurin, via interactions with SAG1. These observations indicate that Laz can serve as an important tool in the study of host-pathogen interactions and is worthy of further study for development into potential therapeutic agents.
Population Pharmacokinetics of Levofloxacin, Gatifloxacin, and Moxifloxacin in Adults with Pulmonary Tuberculosis
Authors: Peloquin Charles A. , Hadad David Jamil , Molino Lucilia Pereira Dutra , Palaci Moises , Boom W. Henry , Dietze Reynaldo , Johnson John L. 
Published: December 2007

ABSTRACT
The objective of this study was to determine the population pharmacokinetic parameters of levofloxacin, gatifloxacin, and moxifloxacin following multiple oral doses. Twenty-nine patients with tuberculosis at the University Hospital in Vitória, Brazil, participated. Subjects received multiple doses of one drug (levofloxacin, 1,000 mg daily, or gatifloxacin or moxifloxacin, 400 mg daily) as part of a 7-day study of early bactericidal activity. Serum samples were collected over 24 h after the fifth dose and assayed using validated high-performance liquid chromatography assays. Concentration-time data were analyzed using noncompartmental, compartmental, and population methods. The three drugs were well tolerated. Levofloxacin produced the highest maximum plasma concentrations (median, 15.55 μg/ml; gatifloxacin, 4.75 μg/ml; moxifloxacin, 6.13 μg/ml), largest volume of distribution (median, 81 liters; gatifloxacin, 79 liters; moxifloxacin, 63 liters), and longest elimination half-life (median, 7.4 h; gatifloxacin, 5.0 h; moxifloxacin, 6.5 h). A one-compartment model, with or without weight as a covariate, adequately described the data. Postmodeling simulations using median population parameter estimates closely approximated the median values from the original data. Area under the concentration-time curve/MIC ratios for free drug were high. All three quinolones showed favorable pharmacokinetic and pharmacodynamic indices, with the most favorable results in this population being seen with levofloxacin at the comparative doses used.
In Vivo Pharmacodynamic Characterization of Anidulafungin in a Neutropenic Murine Candidiasis Model
Authors: Andes D. , Diekema D. J. , Pfaller M. A. , Prince R. A. , Marchillo K. , Ashbeck J. , Hou J. 
Published: December 2007

ABSTRACT

Multiple in vivo studies have characterized the pharmacodynamics of drugs from the triazole and polyene antifungal drug classes. Fewer studies have investigated these pharmacodynamic relationships for the echinocandin drug class. We used a neutropenic murine model of disseminated
Candida albicans
,
Candida tropicalis
, and
Candida glabrata
infection to characterize the time course of activity of the new echinocandin anidulafungin. The pharmacokinetic-pharmacodynamic (PK-PD) indices (the percentage of time that the drug concentration was above the MIC, the ratio of the area under the concentration-time curve from 0 to 24 h [AUC
0-24
] to the MIC, and the ratio of the maximum serum drug concentration [
C
max
] to the MIC) were correlated with in vivo efficacy, as measured by organism numbers in kidney cultures after 96 h of therapy. The kinetics following intraperitoneal anidulafungin dosing in neutropenic infected mice were monitored. Peak levels and AUCs were linear over the 16-fold dose range studied. The drug elimination half-life in serum ranged from 14 to 24 h. Single-dose postantifungal-effect studies demonstrated prolonged suppression of organism regrowth after serum anidulafungin levels had fallen below the MIC. Of the four dosing intervals studied, treatment with the more widely spaced dosing regimens was most efficacious, suggesting the
C
max
/MIC ratio as the PK-PD index most predictive of efficacy. Nonlinear regression analysis suggested that both the
C
max
/MIC and AUC/MIC ratios were strongly predictive of treatment success. Studies were then conducted with 13 additional
C. albicans
,
C. tropicalis
, and
C. glabrata
isolates with various anidulafungin susceptibilities (MICs of anidulafungin for these strains, 0.015 to 2.0 μg/ml) to determine if similar
C
max
/MIC and AUC
0-24
/MIC ratios for these isolates were associated with efficacy. The anidulafungin exposures associated with efficacy were similar among
Candida
species.
Are All the DNA Gyrase Mutations Found in
Mycobacterium leprae
Clinical Strains Involved in Resistance to Fluoroquinolones?
Authors: Matrat Stéphanie , Cambau Emmanuelle , Jarlier Vincent , Aubry Alexandra 
Published: December 2007

ABSTRACT

Mycobacterium leprae
DNA gyrases carrying various mutations, previously described in clinical strains, were investigated for quinolone susceptibility by inhibition of supercoiling and DNA cleavage promotion. We demonstrated that the
gyrA
mutations leading to G89C or A91V confer fluoroquinolone resistance whereas the
gyrB
mutation leading to D205N does not.
Prevalence of and Molecular Basis for Tuberculosis Drug Resistance in the Republic of Georgia: Validation of a QIAplex System for Detection of Drug Resistance-Related Mutations
Authors: Gegia Medea , Mdivani Nino , Mendes Rodrigo E. , Li Haijing , Akhalaia Maka , Han Jian , Khechinashvili George , Tang Yi-Wei 
Published: December 2007

ABSTRACT

We developed a QIAplex system for the simultaneous detection of 24
Mycobacterium tuberculosis
gene mutations responsible for resistance to isoniazid (INH), rifampin (RIF), streptomycin (STM), and ethambutol (EMB) in 196
M. tuberculosis
isolates recovered in the Republic of Georgia. In comparison to phenotypic susceptibility tests, the QIAplex showed sensitivity and specificity of 85.4% and 96.1% for INH, 94.4% and 99.4% for RIF, 69.6% and 99.2% for STM, 50.0% and 98.8% for EBM, and 86.7% and 100.0% for multidrug resistance, respectively. The dominant resistance mutations revealed were a mutation in
katG
resulting in S315T (
katG
S315T),
rpsL
K43R, and
rpoB
S531L. Mutations
katG
S315G and S315T and
rpoB
S531L were detected with higher frequencies in pretreated patients than in naive patients (
P
< 0.05). Simultaneous detection of 24 common drug resistance-related mutations provides a molecular tool for studying and monitoring
M. tuberculosis
resistance mechanism and epidemiology.
In Vitro Activities of Doripenem and Six Comparator Drugs against 423 Aerobic and Anaerobic Bacterial Isolates from Infected Diabetic Foot Wounds
Authors: Goldstein Ellie J. C. , Citron Diane M. , Merriam C. Vreni , Warren Yumi A. , Tyrrell Kerin L. , Fernandez Helen T. 
Published: December 2007

ABSTRACT

Against 182 anaerobe and 241 aerobe strains obtained from diabetic foot infections, doripenem was the most active carbapenem against
Pseudomonas aeruginosa
(MIC
90
, 2 μg/ml), more active than imipenem against
Proteus mirabilis
, and ertapenem was more active against
Escherichia coli
and
Klebsiella
spp. The MIC
50
and MIC
90
values were ≤0.125 μg/ml for methicillin-sensitive
Staphylococcus aureus
and all streptococci and 0.25/1 for
Bacteroides fragilis
.
Genetic and Biochemical Characterization of CAD-1, a Chromosomally Encoded New Class A Penicillinase from
Carnobacterium divergens
Authors: Meziane-Cherif Djalal , Decré Dominique , Høiby E. Arne , Courvalin Patrice , Périchon Bruno 
Published: December 2007

ABSTRACT

Carnobacterium divergens
clinical isolates BM4489 and BM4490 were resistant to penicillins but remained susceptible to combinations of amoxicillin-clavulanic acid and piperacillin-tazobactam. Cloning and sequencing of the responsible determinant from BM4489 revealed a coding sequence of 912 bp encoding a class A β-lactamase named CAD-1. The
bla
CAD-1
gene was assigned to a chromosomal location in the two strains that had distinct pulsed-field gel electrophoresis patterns. CAD-1 shared 53% and 42% identity with β-lactamases from
Bacillus cereus
and
Staphylococcus aureus
, respectively. Alignment of CAD-1 with other class A β-lactamases indicated the presence of 25 out of the 26 isofunctional amino acids in class A β-lactamases.
Escherichia coli
harboring
bla
CAD-1
exhibited resistance to penams (benzylpenicillin and amoxicillin) and remained susceptible to amoxicillin in combination with clavulanic acid. Mature CAD-1 consisted of a 34.4-kDa polypeptide. Kinetic analysis indicated that CAD-1 exhibited a narrow substrate profile, hydrolyzing benzylpenicillin, ampicillin, and piperacillin with catalytic efficiencies of 6,600, 3,200, and 2,900 mM
−1
s
−1
, respectively. The enzyme did not interact with oxyiminocephalosporins, imipenem, or aztreonam. CAD-1 was inhibited by tazobactam (50% inhibitory concentration [IC
50
] = 0.27 μM), clavulanic acid (IC
50
= 4.7 μM), and sulbactam (IC
50
= 43.5 μM). The
bla
CAD-1
gene is likely to have been acquired by BM4489 and BM4490 as part of a mobile genetic element, since it was not found in the susceptible type strain CIP 101029 and was adjacent to a gene for a resolvase.