bluuebunny/crossref_metadata_2025 huggingface dataset:
Caspofungin Susceptibility Testing of Isolates from Patients with Esophageal Candidiasis or Invasive Candidiasis: Relationship of MIC to Treatment Outcome
Authors: Kartsonis Nicholas , Killar John , Mixson Lori , Hoe Chao-Min , Sable Carole , Bartizal Kenneth , Motyl Mary
Published: August 2005

The caspofungin clinical trial database offers an opportunity to assess susceptibility results for
Candida
pathogens obtained from patients with candidiasis and allows for correlations between efficacy outcomes and MICs.
Candida
isolates have been identified from patients enrolled in four studies of esophageal candidiasis and two studies of invasive candidiasis. The MICs of caspofungin for all baseline isolates were measured at a central laboratory using NCCLS criteria (document M-27A); MICs for caspofungin were defined as the lowest concentration inhibiting prominent growth at 24 h. MICs were then compared to clinical and microbiological outcomes across the two diseases. Susceptibility testing for caspofungin was performed on 515 unique baseline isolates of
Candida
spp. obtained from patients with esophageal candidiasis. MICs for caspofungin ranged from 0.008 to 4 μg/ml; the MIC
50
and MIC
90
were 0.5 and 1.0 μg/ml, respectively. Susceptibility testing was also performed on 231 unique baseline isolates of
Candida
spp. from patients with invasive candidiasis. The majority (∼96%) of MICs were between 0.125 and 2 μg/ml, with MIC
50
and MIC
90
for caspofungin being 0.5 and 2.0 μg/ml, respectively. Overall, caspofungin demonstrated potent in vitro activity against clinical isolates of
Candida
species. A relationship between MIC for caspofungin and treatment outcome was not seen for patients with either esophageal candidiasis or invasive candidiasis. Patients with isolates for which the MICs were highest (>2 μg/ml) had better outcomes than patients with isolates for which the MICs were lower (<1 μg/ml). Additionally, no correlation between MIC and outcome was identified for specific
Candida
species.
Delaying the Empiric Treatment of
Candida
Bloodstream Infection until Positive Blood Culture Results Are Obtained: a Potential Risk Factor for Hospital Mortality
Authors: Morrell Matthew , Fraser Victoria J. , Kollef Marin H.
Published: August 2005

Fungal bloodstream infections are associated with significant patient mortality and health care costs. Nevertheless, the relationship between a delay of the initial empiric antifungal treatment until blood culture results are known and the clinical outcome is not well established. A retrospective cohort analysis with automated patient medical records and the pharmacy database at Barnes-Jewish Hospital was conducted. One hundred fifty-seven patients with a
Candida
bloodstream infection were identified over a 4-year period (January 2001 through December 2004). Fifty (31.8%) patients died during hospitalization. One hundred thirty-four patients had empiric antifungal treatment begun after the results of fungal cultures were known. From the time that the first blood sample for culture that was positive was drawn, 9 (5.7%) patients received antifungal treatment within 12 h, 10 (6.4%) patients received antifungal treatment between 12 and 24 h, 86 (54.8%) patients received antifungal treatment between 24 and 48 h, and 52 (33.1%) patients received antifungal treatment after 48 h. Multiple logistic regression analysis identified Acute Physiology and Chronic Health Evaluation II scores (one-point increments) (adjusted odds ratio [AOR], 1.24; 95% confidence interval [CI], 1.18 to 1.31;
P
< 0.001), prior antibiotic treatment (AOR, 4.05; 95% CI, 2.14 to 7.65;
P
= 0.028), and administration of antifungal treatment 12 h after having the first positive blood sample for culture (AOR, 2.09; 95% CI, 1.53 to 2.84;
P
= 0.018) as independent determinants of hospital mortality. Administration of empiric antifungal treatment 12 h after a positive blood sample for culture is drawn is common among patients with
Candida
bloodstream infections and is associated with greater hospital mortality. Delayed treatment of
Candida
bloodstream infections could be minimized by the development of more rapid diagnostic techniques for the identification of
Candida
bloodstream infections. Alternatively, increased use of empiric antifungal treatment in selected patients at high risk for fungal bloodstream infection could also reduce delays in treatment.
Inactivation of Sterol Δ
5,6
-Desaturase Attenuates Virulence in
Candida albicans
Authors: Chau Andrew S. , Gurnani Maya , Hawkinson Robyn , Laverdiere Michel , Cacciapuoti Anthony , McNicholas Paul M.
Published: August 2005

Two clinical
Candida albicans
isolates that exhibited high-level resistance to azoles and modest decreases in susceptibility to amphotericin B were cultured from unrelated patients. Both isolates harbored homozygous nonsense mutations in
ERG3
, which encodes an enzyme, sterol Δ
5,6
-desaturase, involved in ergosterol synthesis. Extraction and analysis of the sterols from both isolates confirmed the absence of sterol Δ
5,6
-desaturase activity. Although the loss of sterol Δ
5,6
-desaturase activity is known to confer resistance to azoles, this mechanism of resistance has rarely been seen in clinical isolates, suggesting that such mutants are at a competitive disadvantage. To test this hypothesis, the virulence of the
erg3
mutants was assayed by using a mouse systemic infection model. The mutants were significantly less virulent than the wild-type comparator strains. However, the kidney fungal burdens in mice infected with the
erg3
mutants were similar to those in mice infected with the wild-type strains. Similar results were obtained by using a laboratory-generated homozygous
erg3
deletion mutant (D. Sanglard et al., Antimicrob. Agents Chemother. 47:2404-2412, 2003). Reintroduction of a wild-type
ERG3
allele into the homozygous deletion mutant restored virulence, ergosterol synthesis, and susceptibility to azoles, confirming that these phenotypic changes were solely due to the inactivation of Erg3p.
2,4-Diaminopteridine-Based Compounds as Precursors for De Novo Synthesis of Antifolates: a Novel Class of Antimalarials
Authors: Nduati Eunice , Hunt Sonya , Kamau Eddy M. , Nzila Alexis
Published: August 2005

We have tested the hypothesis that 2,4-diamino-6-hydroxymethyl-pteridine (DAP), 2,4-diaminopteroic acid (DAPA), and 2,4 diamino-N10-methyl-pteroic acid (DAMPA) could be converted into aminopterin (from DAP and DAPA) and methotrexate (from DAMPA), both of which are potent inhibitors of dihydrofolate reductase, a proven drug target forPlasmodium falciparum. DAP, DAPA, and DAMPA inhibited parasite growth in the micromolar range; DAMPA was the most active, with 50% inhibitory concentrations in vitro of 446 ng/ml against the antifolate-sensitive strain and 812 ng/ml against the highly resistant strain under physiological folate conditions. DAMPA potentiates the activity of the sulfone dapsone, an inhibitor of dihydropteroate synthase, but not that of chlorcycloguanil, a known inhibitor of dihydrofolate reductase (DHFR). Experiments with aSaccharomyces cerevisiaestrain dependent upon theP. falciparumDHFR enzyme showed that DHFR is a target of DAMPA in that system. We hypothesize that DAMPA is converted to methotrexate by the parasite dihydrofolate synthase, which explains the synergy of DAMPA with dapsone but not with chlorcycloguanil. This de novo synthesis will not occur in the host, since it lacks the complete folate pathway. If this hypothesis holds true, the de novo synthesis of the toxic compounds could be used as a framework for the search for novel potent antimalarial antifolates.
Quinine Pharmacokinetics and Pharmacodynamics in Children with Malaria Caused by
Plasmodium falciparum
Authors: Le Jouan M. , Jullien V. , Tetanye E. , Tran A. , Rey E. , Tréluyer J.-M. , Tod M. , Pons G.
Published: August 2005

The aim of the present study was to assess the pharmacokinetics and the efficacy of a shorter than usual 5-day quinine treatment given orally to children in Cameroon with malaria caused by
Plasmodium falciparum
. Quinine (8.3 mg of base per kg of body weight every 8 h) was administered as a 2% formiate salt syrup for 5 days to 30 children (age range, 0.55 to 6.7 years) with uncomplicated falciparum malaria (initial parasitemia, 1.4 × 10
3
to 1.8 × 10
5
/μl). Quinine concentrations in plasma samples (five to nine per patient) were measured by liquid chromatography on days 1 to 3. Parasitemia was counted on days 0, 1, 2, 3, 4, 7, and 14. Pharmacokinetic and pharmacodynamic data were analyzed by population approaches by using NONMEM and WinBugs, respectively. The kinetics of quinine were best described by a one-compartment model with time-varying protein binding. Clearance and the volume of distribution were positively correlated with body weight and increased over time. Parasitemia was undetectable from day 3 to 14 in all children. The time to a 4-log reduction of the initial level of parasitemia (
T
er
) was related to the average quinine concentration from 0 to 72 h (
C
av
) as
T
er
=
T
min
[1 + (
C
50
/
C
av
)

s

], where sigmoidicity (
s
) is equal to 2,
T
min
is the time to eradication at infinite
C
av
, and
C
50
is the value of
C
av
for which
T
er
is twice
T
min
. The
C
50
distribution was unimodal, and all
C
50
values were less than 8 mg/liter, while
C
av
ranged from 5.9 to 18.3 mg/liter. The median (10th to 90th percentile)
T
er
was 47 h (range, 39 to 76 h). The efficacy of a 5-day treatment course should be evaluated in a larger clinical trial.
Absolute Bioavailability and Pharmacokinetics of Linezolid in Hospitalized Patients Given Enteral Feedings
Authors: Beringer Paul , Nguyen Megan , Hoem Nils , Louie Stan , Gill Mark , Gurevitch Michael , Wong-Beringer Annie
Published: August 2005

Linezolid is a new antimicrobial agent effective against drug-resistant gram-positive pathogens which are common causes of infections in hospitalized patients. Many such patients rely on the intravenous or enteral route for nutrition and drug administration. Therefore, the bioavailability of linezolid administered enterally in the presence of enteral feedings in hospitalized patients was examined. Eighteen subjects were assessed in a randomized single-dose crossover study; 12 received continuous enteral feedings, while 6 did not (controls). Both groups received linezolid 600 mg intravenously and orally (control) or enterally, with the alternate route of administration separated by a 24-h washout period. Pharmacokinetic parameters derived from noncompartmental and compartmental analysis incorporating linear and nonlinear elimination pathways were compared between groups:F,Ka,Vs,K23,K32,Vmax,Km, andK20(bioavailability, absorption rate constant, volume of central compartment normalized to body weight, intercompartmental rate constants, maximum velocity, Michaelis-Menten constant, and elimination rate constant, respectively). Pharmacokinetic (PK) data were available from 17 patients. The linezolid oral suspension was rapidly and completely absorbed by either the oral or enteral route of administration. Bioavailability was unaltered in the presence of enteral feedings. PK estimates remain similar regardless of the model applied. At the therapeutic dose used, only slight nonlinearity in elimination was observed. A linezolid oral suspension may be administered via the enteral route to hospitalized patients without compromise in its excellent bioavailability and rapid rate of absorption. Compartmental pharmacokinetic analysis offers a more flexible study application, since bioavailability (F) can be estimated directly with intermixed intravenous/oral doses without a need for a washout period.
Purine Nucleobase Transport in Amastigotes of
Leishmania mexicana
: Involvement in Allopurinol Uptake
Authors: Al-Salabi Mohammed I. , de Koning Harry P.
Published: August 2005

Nucleobase and nucleoside transporters play central roles in the biochemistry of parasitic protozoa, as they lack the ability to synthesize purines de novo and are absolutely reliant upon purine salvage from their hosts. Furthermore, such transporters are potentially critical to the pharmacology of these important human pathogens, because they mediate the uptake of purine analogues, as well as some nonpurine drugs, that can be selectively cytotoxic to the parasites. We here report the first identification and characterization of a purine nucleobase transporter in
Leishmania
amastigotes. Uptake of [
3
H]hypoxanthine by
Leishmania mexicana
amastigotes was mediated by a single high-affinity transporter, LmexNBT1, with a

K
m

of 1.6 ± 0.4 μM and high affinity for adenine, guanine, and xanthine but low affinity for nucleosides and pyrimidine nucleobases. Allopurinol, an antileishmanial hypoxanthine analogue, was apparently taken up by the same transporter. Using [
3
H]allopurinol, a

K
m

value of 33.6 ± 6.0 μM was obtained. All evidence was compatible with a model of a single purine nucleobase transporter being expressed in amastigotes. Using various purine nucleobase analogues, a model for the interactions between hypoxanthine and the transporter's permeant binding site was constructed. The binding interactions were compared with those of the LmajNBT1 transporter in
Leishmania major
promastigotes and found to be very similar.
Development of a Novel Targeting System for Lethal Photosensitization of Antibiotic-Resistant Strains of
Staphylococcus aureus
Authors: Embleton Michelle L. , Nair Sean P. , Heywood Wendy , Menon Dev C. , Cookson Barry D. , Wilson Michael
Published: August 2005

Light-activated antimicrobial agents (photosensitizers) are promising alternatives to antibiotics for the treatment of topical infections. To improve efficacy and avoid possible damage to host tissues, targeting of the photosensitizer to the infecting organism is desirable, and this has previously been achieved using antibodies and chemical modification of the agent. In this study we investigated the possibility of using a bacteriophage to deliver the photosensitizer tin(IV) chlorin e6 (SnCe6) to
Staphylococcus aureus
. SnCe6 was covalently linked to
S. aureus
bacteriophage 75, and the ability of the conjugate to kill various strains of
S. aureus
when exposed to red light was determined. Substantial kills of methicillin- and vancomycin-intermediate strains of
S. aureus
were achieved using low concentrations of the conjugate (containing 1.5 μg/ml SnCe6) and low light doses (21 J/cm
2
). Under these conditions, the viability of human epithelial cells (in the absence of bacteria) was largely unaffected. On a molar equivalent basis, the conjugate was a more effective bactericide than the unconjugated SnCe6, and killing was not growth phase dependent. The conjugate was effective against vancomycin-intermediate strains of
S. aureus
even after growth in vancomycin. The results of this study have demonstrated that a bacteriophage can be used to deliver a photosensitizer to a target organism, resulting in enhanced and selective killing of the organism. Such attributes are desirable in an agent to be used in the photodynamic therapy of infectious diseases.
Pharmacokinetic Modeling of Free Amoxicillin Concentrations in Rat Muscle Extracellular Fluids Determined by Microdialysis
Authors: Marchand Sandrine , Chenel Marylore , Lamarche Isabelle , Couet William
Published: August 2005

The aim of the present study was to investigate amoxicillin (AMX) distribution in muscle interstitial fluid by microdialysis in healthy, awake rats. Microdialysis probes were inserted into the jugular vein and hind leg muscle. Probe recoveries in each rat were determined by retrodialysis with cefadroxil. AMX was administered as a bolus dose of 50 mg · kg
−1
, and microdialysis samples were collected during 180 min. Concentrations of unbound drug in blood and muscle were analyzed simultaneously by a population approach. Simulations were conducted using a hybrid, physiologically based pharmacokinetic model to investigate the potential impact of tissue blood flow on muscle AMX distribution. A two-compartment pharmacokinetic model described adequately the unbound amoxicillin concentration-time profiles in blood and muscle. Muscle AMX distribution equilibrium was rapidly achieved. Consequently, the best results were obtained by considering concentrations in muscle as part of the central compartment. The ratio of the concentration of unbound drug in muscle to that in blood (
R
model
) was estimated to 0.80 by the model, which is close to the mean value obtained by noncompartmental data analysis (
R
area
= 0.86 ± 0.29). Simulations conducted with a hybrid, physiologically based pharmacokinetic model suggest that a muscle blood flow reduction of 30% to 50%, such as could be encountered in critical care patients, has virtually no effect on muscle AMX concentration profiles. In conclusion, this study has clearly demonstrated that AMX distributes rapidly and extensively within muscle interstitial fluid, consistent with theory, and that altered muscle blood flow seems unlikely to have a major effect on these distribution characteristics.
In Vitro Efficacies of Nitazoxanide and Other Thiazolides againstNeospora caninumTachyzoites Reveal Antiparasitic Activity Independent of the Nitro Group
Authors: Esposito Marco , Stettler Rebecca , Moores Shelley L. , Pidathala Chandrakala , Müller Norbert , Stachulski Andrew , Berry Neil G. , Rossignol Jean-Francois , Hemphill Andrew
Published: August 2005

The thiazolide nitazoxanide [2-acetolyloxy-N-(5-nitro-2-thiazolyl)benzamide] (NTZ) exhibits a broad spectrum of activities against a wide variety of intestinal and tissue-dwelling helminths, protozoa, and enteric bacteria infecting animals and humans. The drug has been postulated to act via reduction of its nitro group by nitroreductases, including pyruvate ferredoxin oxidoreductase. In this study, we investigated the efficacies of nitazoxanide and a number of other thiazolides againstNeospora caninumtachyzoites in vitro. We employed real-time-PCR-based monitoring of tachyzoite adhesion, invasion, and intracellular proliferation, as well as electron microscopic visualization of the effects imposed by nitazoxanide. In addition, we investigated several modified versions of this drug. These modifications included on one hand the replacement of the nitro group on the thiazole ring with a bromide, thus removing the most reactive group, and on the other hand the differential positioning of methyl groups on the salicylate ring. We show that the thiazole-associated nitro group is not necessarily required for the action of the drug and that methylation of the salicylate ring can result in complete abrogation of the antiparasitic activity, depending on the positioning of the methyl group. These findings indicate that other mechanisms besides the proposed mode of action involving the pyruvate ferredoxin oxidoreductase enzyme could be responsible for the wide spectrum of antiparasitic activity of NTZ and that modifications in the benzene ring could be important in these alternative mechanisms.
Comparative Activities of Lipid Esters of Cidofovir and Cyclic Cidofovir against Replication of Herpesviruses In Vitro
Authors: Williams-Aziz Stephanie L. , Hartline Caroll B. , Harden Emma A. , Daily Shannon L. , Prichard Mark N. , Kushner Nicole L. , Beadle James R. , Wan W. Brad , Hostetler Karl Y. , Kern Earl R.
Published: August 2005

Cidofovir (CDV) is an effective therapy for certain human cytomegalovirus (HCMV) infections in immunocompromised patients that are resistant to other antiviral drugs, but the compound is not active orally. To improve oral bioavailability, a series of lipid analogs of CDV and cyclic CDV (cCDV), including hexadecyloxypropyl-CDV and -cCDV and octadecyloxyethyl-CDV and -cCDV, were synthesized and found to have multiple-log-unit enhanced activity against HCMV in vitro. On the basis of the activity observed with these analogs, additional lipid esters were synthesized and evaluated for their activity against herpes simplex virus (HSV) types 1 and 2, human cytomegalovirus, murine cytomegalovirus, varicella-zoster virus (VZV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), and HHV-8. Using several different in vitro assays, concentrations of drug as low as 0.001 μM reduced herpesvirus replication by 50% (EC
50
) with the CDV analogs, whereas the cCDV compounds were generally less active. In most of the assays performed, the EC
50
values of the lipid esters were at least 100-fold lower than the EC
50
values for unmodified CDV or cCDV. The lipid analogs were also active against isolates that were resistant to CDV, ganciclovir, or foscarnet. These results indicate that the lipid ester analogs are considerably more active than CDV itself against HSV, VZV, CMV, EBV, HHV-6, and HHV-8 in vitro, suggesting that they may have potential for the treatment of infections caused by a variety of herpesviruses.
Design of a Small-Molecule Entry Inhibitor with Activity against Primary Measles Virus Strains
Authors: Plemper Richard K. , Doyle Joshua , Sun Aiming , Prussia Andrew , Cheng Li-Ting , Rota Paul A. , Liotta Dennis C. , Snyder James P. , Compans Richard W.
Published: August 2005

The incidence of measles virus (MV) infection has been significantly reduced in many nations through extensive vaccination; however, the virus still causes significant morbidity and mortality in developing countries. Measles outbreaks also occur in some developed countries that have failed to maintain high vaccine coverage rates. While vaccination is essential in preventing the spread of measles, case management would greatly benefit from the use of therapeutic agents to lower morbidity. Thus, the development of new therapeutic strategies is desirable. We previously reported the generation of a panel of small-molecule MV entry inhibitors. Here we show that our initial lead compound, although providing proof of concept for our approach, has a short half-life (<16 h) under physiological conditions. In order to combine potent antiviral activity with increased compound stability, a targeted library of candidate molecules designed on the structural basis of the first lead has been synthesized and tested against MV. We have identified an improved lead with low toxicity and high stability (half-life ≫ 16 h) that prevents viral entry and hence infection. This compound shows high MV specificity and strong activity (50% inhibitory concentration = 0.6 to 3.0 μM, depending on the MV genotype) against a panel of wild-type MV strains representative of viruses that are currently endemic in the field.
Intensive Therapy with Ceftobiprole Medocaril of Experimental Foreign-Body Infection by Methicillin-Resistant
Staphylococcus aureus
Authors: Vaudaux Pierre , Gjinovci Asllan , Bento Manuela , Li Dongmei , Schrenzel Jacques , Lew Daniel P.
Published: August 2005

The therapeutic activity of ceftobiprole medocaril, the water-soluble prodrug of ceftobiprole, was compared to that of vancomycin in a rat tissue cage model of chronic methicillin-resistant
Staphylococcus aureus
(MRSA) foreign-body infection. The MICs and MBCs of ceftobiprole and vancomycin in Mueller-Hinton broth for strain MRGR3 were 1 and 4 and 1 and 2 μg/ml, respectively. In vitro elimination rates of strain MRGR3 of 4 and 8 μg/ml of ceftobiprole or vancomycin were equivalent. After 2 weeks of infection, mean ± standard error of the mean viable counts of strain MRGR3 were 6.83 ± 0.11 log CFU/ml of tissue cage fluid (
n
= 87). High-dose regimens of ceftobiprole medocaril (equivalent to 150 mg/kg of ceftobiprole) or 50 mg/kg vancomycin produced nearly identical average peak and trough levels of ceftobiprole and vancomycin in tissue cage fluid, which exceeded the MBC of either antibiotic towards strain MRGR3 for ≥75% of each dosing interval. After 7 days of therapy with ceftobiprole medocaril or vancomycin, average counts of MRGR3 decreased significantly (
P
< 0.02) by 0.68 ± 0.28 (
n
= 29) and 0.88 ± 0.22 (
n
= 28) log CFU/ml of tissue cage fluid, respectively, compared with cages of untreated animals, but were not significantly different from each other. No resistant mutants were detected on ceftobiprole-supplemented agar following therapy with this cephalosporin. The in vivo activity of ceftobiprole medocaril against chronic MRSA foreign-body infections was equivalent to that of vancomycin and did not lead to the emergence of resistant subpopulations.
Atazanavir Signature I50L Resistance Substitution Accounts for Unique Phenotype of Increased Susceptibility to Other Protease Inhibitors in a Variety of Human Immunodeficiency Virus Type 1 Genetic Backbones
Authors: Weinheimer S. , Discotto L. , Friborg J. , Yang H. , Colonno R.
Published: August 2005

Substitution of leucine for isoleucine at residue 50 (I50L) of human immunodeficiency virus (HIV) protease is the signature substitution for atazanavir (ATV) resistance. A unique phenotypic profile has been associated with viruses containing the I50L substitution, which produces ATV-specific resistance and increased susceptibility to most other approved HIV protease inhibitors (PIs). The basis for this unique phenotype has not been clearly elucidated. In this report, a direct effect of I50L on the susceptibility to the PI class is described. Cell-based protease assays using wild-type and PI-resistant proteases from laboratory and clinical isolates and in vitro antiviral assays were used to demonstrate a strong concordance between changes in PI susceptibility at the level of protease inhibition and changes in susceptibility observed at the level of virus infection. The results show that the induction of ATV resistance and increased susceptibility to other PIs by the I50L substitution is likely determined at the level of protease inhibition. Moreover, the I50L substitution functions to increase PI susceptibility even in the presence of other primary and secondary PI resistance substitutions. These findings may have implications regarding the optimal sequencing of PI therapies necessary to preserve PI treatment options of patients with ATV-resistant HIV infections.
In Vitro and In Vivo Effects of Soluble, Monovalent Globotriose on Bacterial Attachment and Colonization
Authors: Leach James L. , Garber Stacey A. , Marcon Andrea A. , Prieto Pedro A.
Published: August 2005

Epithelial cells lining the urinary tract are rich in globo series glycolipids, structurally defined by a Galα1,4Gal motif in the oligosaccharide moiety of this glycolipid family. This Galα1,4Gal motif is the attachment target for the P-fimbrial adhesin of uropathogenic
Escherichia coli
. We investigated the ability of a trisaccharide analog of this core motif, globotriose (Galα1,4Galβ1,4Glc), to interfere with uropathogen attachment and colonization in vitro and in vivo. We assessed the ability of globotriose to inhibit and reverse the binding and agglutination of a P-fimbriated strain of
E. coli
(JR1) using human erythrocytes and immortalized human colonic epithelial cells as targets. Globotriose (5 mg/ml) completely inhibited and reversed cell agglutination and caused a 10- to 100-fold reduction in JR1 binding to target cells, as determined by flow cytometry. In preparation for an in vivo efficacy study, we investigated the distribution and pharmacokinetics of globotriose in the BALB/c mouse. Globotriose was administered via the tail vein, targeting an instantaneous plasma concentration of 5 mg/ml, and in a different experiment, animals were gavaged at 10 times the intravenous (i.v.) dose. Globotriose was rapidly cleared from plasma (half-life [
t
1/2
], 6 min) and slowly excreted via the kidney (
t
1/2
, 4 h). Urine levels of >5 mg/ml were maintained from 4 to 12 h after the i.v. bolus dose, which resulted in a 1-log reduction in established bladder colonization by JR1. These results suggest that free, soluble globotriose is a feasible alternative therapy for urinary tract infections.
Molecular Basis of Azithromycin-Resistant
Pseudomonas aeruginosa
Biofilms
Authors: Gillis Richard J. , White Kimberly G. , Choi Kyoung-Hee , Wagner Victoria E. , Schweizer Herbert P. , Iglewski Barbara H.
Published: August 2005

Pseudomonas aeruginosa
biofilms are extremely recalcitrant to antibiotic treatment. Treatment of cystic fibrosis patients with azithromycin (AZM) has shown promise. We used DNA microarrays to identify differentially expressed transcripts in developing
P. aeruginosa
biofilms exposed to 2 μg/ml AZM. We report that transcripts for multiple restriction-nodulation-cell division (RND) efflux pumps, known to be involved in planktonic antibiotic resistance, and transcripts involved in type III secretion were upregulated in the resistant biofilms that developed in the presence of AZM. Interestingly, the MexAB-OprM and MexCD-OprJ efflux pumps, but not type III secretion, appear to be integral to biofilm formation in the presence of AZM, as evidenced by the fact that a mutant deleted in both
mexAB-oprM
and
mexCD-oprJ
was unable to form a biofilm in the presence of AZM. A mutant deleted in type III secretion was still able to form biofilms in the presence of drug. Furthermore, single
mexAB-oprM
- and
mexCD-oprJ
-null mutants were able to form a biofilm in the presence of drug, indicating that either of the pumps can confer resistance to AZM during biofilm development. In contrast to planktonically grown cells, where no
mexC
expression was detectable regardless of the presence of AZM, biofilms exhibited induction of
mexC
expression from the outset of their formation, but only in the presence of AZM.
mexA
, which is constitutively expressed in planktonic cells, was uniformly expressed in biofilms regardless of the presence of AZM. These data indicate that the MexCD-OprJ pump acts as a biofilm-specific mechanism for AZM resistance.
Effects of Intratracheal Administration of Novispirin G10 on a Rat Model of Mucoid
Pseudomonas aeruginosa
Lung Infection
Authors: Song Zhijun , Wu Hong , Mygind Per , Raventos Dora , Sonksen Carsten , Kristensen Hans-Henrik , Høiby Niels
Published: August 2005

Chronic
Pseudomonas aeruginosa
lung infection is a major problem for patients with cystic fibrosis (CF). The biofilm mode of growth of the pathogen makes it highly resistant to antibiotic treatment, and this is especially pronounced with mucoid strains. In this study, novispirin G10, a synthetic antimicrobial peptide patterned loosely on sheep myeloid antimicrobial peptide 29, was tested in a rat model of mucoid
P. aeruginosa
lung infection.
P. aeruginosa
NH57388A, a mucoid strain isolated from a CF patient, was mixed with the alginate produced by the bacterium itself and adjusted to a concentration of 10
10
CFU/ml. Each rat received 10
9
CFU of bacteria intratracheally in the left lung to establish lung infection. At 0 and 3 h post
P. aeruginosa
infection, the treated group of rats received novispirin G10 (0.1 mg/ml, 0.1 ml/rat) intratracheally, whereas the control group received vehicle treatment only. The animals were sacrificed on days 3, 5, 7, and 10 after challenge for evaluation of various parameters. On day 5, 50% of the rats in the treated group had cleared the bacteria from the lungs, whereas in the control group, none of the rats cleared the pathogen (
P
< 0.03). The average bacterial loads remaining in the lungs of treated rats on days 3 and 5 were more than 170- and 330-fold lower than in the control groups (
P
< 0.0005 and
P
< 0.0003). In accordance, the macroscopic and microscopic lung pathology was also significantly milder in the treated group compared to the control group (
P
< 0.0002). Lung cytokine responses in the treated group were significantly lower than in the control group. The results suggest that novispirin G10 might be useful in treating antibiotic-resistant
P. aeruginosa
lung infections.
Salivary Antimicrobial Peptide Expression and Dental Caries Experience in Children
Authors: Tao Renchuan , Jurevic Richard J. , Coulton Kimberly K. , Tsutsui Marjorie T. , Roberts Marilyn C. , Kimball Janet R. , Wells Norma , Berndt Jeffery , Dale Beverly A.
Published: August 2005

Dental caries is a major worldwide oral disease problem in children. Although caries are known to be influenced by dietary factors, the disease results from a bacterial infection; thus, caries susceptibility may be affected by host factors such as salivary antimicrobial peptides. This study aimed to determine a possible correlation between caries prevalence in children and salivary concentrations of the antimicrobial peptides human beta-defensin-3 (hBD-3), the cathelicidin LL37, and the alpha-defensins HNP1-3 (a mixture of HNP1, 2, 3). Oral examinations were performed on 149 middle school children, and unstimulated whole saliva was collected for immunoassays of the three peptides and for assay of caries-causing bacteria in saliva. The median salivary levels of hBD-3, LL37, and HNP1-3 were in the microgram/ml range but were highly variable in the population. While levels of LL37 and hBD-3 did not correlate with caries experience, the median HNP1-3 levels were significantly higher in children with no caries than in children with caries. Children with high caries levels did not have high levels of salivary
Streptococcus mutans
, and the HNP1-3 level was not correlated with salivary
S. mutans
. By immunohistochemistry we localized HNP1-3 in submandibular salivary duct cells. HNPs are also released by neutrophils into the gingival crevicular fluid. Both sources may account for their presence in saliva. Low salivary levels of HNP1-3 may represent a biological factor that contributes to caries susceptibility. This observation could lead to new ways to screen for caries susceptibility and to new means of assessing the risk for this common oral problem.
Effect of Medium Age and Supplementation with the Biocatalytic Oxygen-Reducing Reagent Oxyrase on In Vitro Activities of Tigecycline against Recent Clinical Isolates
Authors: Petersen Peter J. , Bradford Patricia A.
Published: August 2005

In determining the quality control limits for the Clinical Laboratory Standards Institute-recommended quality control organisms with tigecycline, a number of inconsistencies in the results were encountered that appeared to be related to the age of the Mueller-Hinton broth II. This study was performed to examine the effect of medium age and supplementation with Oxyrase on the activity of tigecycline using a large number of clinical isolates.
Mutations Associated with Sulfadoxine-Pyrimethamine and Chlorproguanil Resistance in
Plasmodium falciparum
Isolates from Blantyre, Malawi
Authors: Alker Alisa P. , Mwapasa Victor , Purfield Anne , Rogerson Stephen J. , Molyneux Malcolm E. , Kamwendo Deborah D. , Tadesse Eyob , Chaluluka Ebbie , Meshnick Steven R.
Published: August 2005

We conducted a prevalence study of mutations in
Plasmodium falciparum
that are associated with antifolate resistance in Blantyre, Malawi. The dihydrofolate reductase 164-Leu mutation, which confers resistance to both pyrimethamine and chlorproguanil, was found in 4.7% of the samples. Previously unreported mutations in dihydropteroate synthase were also found.
Multiparametric Assay To Screen and Dissect the Mode of Action of Anti-Human Immunodeficiency Virus Envelope Drugs
Authors: Blanco Julià , Clotet-Codina Imma , Bosch Berta , Armand-Ugón Mercedes , Clotet Bonaventura , Esté José A.
Published: August 2005

A flow cytometry-based assay was used to simultaneously quantify X4 and R5 human immunodeficiency virus (HIV) envelope-mediated cell-to-cell viral transfer, cell death, and cell-to-cell fusion. In this assay, different anti-HIV envelope drugs showed characteristic inhibitory profiles for each measured parameter, allowing for the rapid identification of the mode of action of active compounds.
In Vitro Selection and Analysis of Human Immunodeficiency Virus Type 1 Resistant to Derivatives of β-2′,3′-Didehydro-2′,3′-Dideoxy-5-Fluorocytidine
Authors: Hammond Jennifer L. , Parikh Urvi M. , Koontz Dianna L. , Schlueter-Wirtz Susan , Chu Chung K. , Bazmi Hengameh Z. , Schinazi Raymond F. , Mellors John W.
Published: August 2005

Serial passage of human immunodeficiency virus type 1 in MT-2 cells in increasing concentrations of the
d
- and
l
-enantiomers of β-2′,3′-didehydro-2′,3′-dideoxy-5-fluorocytidine (d4FC) resulted in the selection of viral variants with reverse transcriptase substitutions M184I or M184V for
l
-d4FC and I63L, K65R, K70N, K70E, or R172K for
d
-d4FC. Phenotypic analysis of site-directed mutants defined the role of these mutations in reducing susceptibility to
l
- or
d
-d4FC.
Correlation between Ceftriaxone Resistance of
Salmonella enterica
Serovar Typhimurium and Expression of Outer Membrane Proteins OmpW and Ail/OmpX-Like Protein, Which Are Regulated by BaeR of a Two-Component System
Authors: Hu Wensi S. , Li Pei-Chuan , Cheng Chao-Yin
Published: August 2005

Mutant 7F2 of
Salmonella enterica
serovar Typhimurium has a transposon inserted in the regulator gene
baeR
of a two-component system and showed a more-than-fourfold reduction in resistance to ceftriaxone. Complementation analysis suggested an association among the outer membrane proteins OmpW and STM3031, ceftriaxone resistance, and
baeR
.
Effect of Simvastatin, an Established Lipid-Lowering Drug, on Pulmonary
Chlamydia pneumoniae
Infection in Mice
Authors: Erkkilä Leena , Jauhiainen Matti , Laitinen Kirsi , Haasio Kristiina , Tiirola Terttu , Saikku Pekka , Leinonen Maija
Published: August 2005

The effects of simvastatin treatment on
Chlamydia pneumoniae
lung infection, inflammation, and serum lipids in mouse model were studied. Simvastatin decreased viable chlamydial counts and increased inflammatory cell infiltrates in the lung tissue, suggesting that simvastatin treatment had both antichlamydial and immunomodulatory effects during an acute
C. pneumoniae
infection.
Postantibiotic Effect of DX-619 against 16 Gram-Positive Organisms
Authors: Pankuch G. A. , Appelbaum P. C.
Published: August 2005

The in vitro postantibiotic effects (PAEs), the postantibiotic sub-MIC effects (PA-SMEs), and the sub-MIC effects (SMEs) of DX-619 were determined for 16 gram-positive organisms. DX-619 pneumococcal, staphylococcal, and enterococcal PAE ranges were 1.7 to 5.0 h, 0.7 to 1.8 h, and 1.2 to 6.5 h, respectively. The PA-SME ranges (0.4× MIC) for pneumococci, staphylococci, and enterococci were 5.2 to >8.6 h, 2.1 to 8.3 h, and 4.9 to >10.0 h, respectively.
Nevirapine Plasma Exposure Affects both Durability of Viral Suppression and Selection of Nevirapine Primary Resistance Mutations in a Clinical Setting
Authors: González de Requena D. , Bonora S. , Garazzino S. , Sciandra M. , D'Avolio A. , Raiteri R. , Marrone R. , Boffito M. , De Rosa F. G. , Sinicco A. , Di Perri G.
Published: August 2005

The relationship between nevirapine plasma concentrations and the durability of both viral suppression (VS) and selection of nevirapine primary resistance mutations (PRMs) was evaluated. A nevirapine trough concentration (
C
trough
) of >4,300 ng/ml was found to predict longer VS. Patients with nevirapine
C
trough
s ranging from 3,100 to 4,300 ng/ml had higher probabilities of developing PRMs than those with nevirapine
C
trough
s below and above this concentration interval.
Microbiologic and Immunologic Evaluation of a Single High Dose of Azithromycin for Treatment of Experimental
Mycoplasma pneumoniae
Pneumonia
Authors: Ríos Ana María , Fonseca-Aten Mónica , Mejías Asunción , Chávez-Bueno Susana , Katz Kathy , Gómez Ana María , McCracken George H. , Ramilo Octavio , Hardy R. Doug
Published: August 2005

We evaluated the efficacy of azithromycin therapy given as a single high dose or divided over 5 days for the treatment of mild experimental
Mycoplasma pneumoniae
pneumonia. Although both azithromycin regimens significantly reduced quantitative cultures, lung histopathology, and pulmonary cytokines and chemokines, there were no significant differences between the two regimens.
Activities of Rifamycin Derivatives against Wild-Type and
rpoB
Mutants of
Chlamydia trachomatis
Authors: Xia Minsheng , Suchland Robert J. , Carswell Joli A. , Van Duzer John , Buxton Debra K. , Brown Kara , Rothstein David M. , Stamm Walter E.
Published: August 2005

Rifalazil, a semisynthetic rifamycin, was shown previously to have exceptional potency against
Chlamydia trachomatis
(MIC of 0.00025 μg/ml). We therefore tested 250 additional rifamycin derivatives and identified 12 with activities that are eightfold more potent than that of rifalazil. These compounds also showed exceptional activities against rifampin-resistant strains that carry missense mutations in the
rpoB
gene. The antimicrobial potency and intracellular penetration of these agents suggest their potential in treatment of chlamydial infections.
Emergence of Fluoroquinolone Resistance in
Mycobacterium tuberculosis
during Continuously Dosed Moxifloxacin Monotherapy in a Mouse Model
Authors: Ginsburg Amy Sarah , Sun Ronggai , Calamita Heather , Scott Cherise P. , Bishai William R. , Grosset Jacques H.
Published: August 2005

Fluoroquinolone resistance in tuberculosis may rapidly emerge. Mice infected with high titers of aerosolized
Mycobacterium tuberculosis
and treated for 8 weeks with four concentrations of moxifloxacin (0.125, 0.25, 0.50, and 1.0%) mixed into the diet had drug concentrations of 2.4, 4.1, 5.3, and 17.9 μg/ml, respectively, in blood. Selection of fluoroquinolone-resistant mutants occurred in all surviving mice.
Guillain Barré syndrome precipitated by the use of antilymphocyte globulin in the treatment of severe aplastic anaemia
Authors: Kaya B , Davies C E , Oakervee H E , Silver N C , Gawler J , Cavenagh J D
Published: August 2005

This report describes the case of a 54 year old woman with very severe aplastic anaemia who was treated with antilymphocyte globulin (ALG) and developed Guillain Barré syndrome (GBS). No antecedent infective aetiology was identified. Although there are numerous reports of autoimmune disease after treatment with ALG in aplastic anaemia, and GBS after immunosuppressive treatment, there are none reporting GBS after the use of ALG for severe aplastic anaemia. The occurrence of autoimmune disease after immunosuppressive treatment, in particular ALG, is discussed, together with the possible mechanisms that result from T cell depression.
A novel wavelet neural network based pathological stage detection technique for an oral precancerous condition
Authors: Paul R R , Mukherjee A , Dutta P K , Banerjee S , Pal M , Chatterjee J , Chaudhuri K , Mukkerjee K
Published: August 2005

Aim:To describe a novel neural network based oral precancer (oral submucous fibrosis; OSF) stage detection method.

Method:The wavelet coefficients of transmission electron microscopy images of collagen fibres from normal oral submucosa and OSF tissues were used to choose the feature vector which, in turn, was used to train the artificial neural network.

Results:The trained network was able to classify normal and oral precancer stages (less advanced and advanced) after obtaining the image as an input.

Conclusions:The results obtained from this proposed technique were promising and suggest that with further optimisation this method could be used to detect and stage OSF, and could be adapted for other conditions.
Sarcoidosis and HTLV-1 infection: Figure 1
Authors: McKee D H , Young A C , Haeney M
Published: August 2005

An asymptomatic, homosexual, white man was found to have an abnormal chestx ray. A presumptive diagnosis of sarcoidosis was made, but pulmonary function tests and a transbronchial biopsy were normal. He then remained asymptomatic for 10 years until he developed a progressive spastic paraparesis. At this point, antibodies to human T cell lymphotropic virus type 1 (HTLV-1) were identified in the serum and cerebrospinal fluid, and the diagnosis of HTLV-1 associated myelopathy was made, the history suggesting sexual exposure to HTLV-1 many years previously. HTLV-1 is associated with a spectrum of immune related disorders, including a pulmonary sarcoid-like syndrome. Infection with this chronic proinflammatory retrovirus should be considered in the differential diagnosis of all immune disorders in at risk individuals.
Persistent high risk HPV infection associated with development of cervical neoplasia in a prospective population study
Authors: Cuschieri K S , Cubie H A , Whitley M W , Gilkison G , Arends M J , Graham C , McGoogan E
Published: August 2005

Aims:To monitor the association between the course of high risk human papillomavirus (HR-HPV) infection and the development of cervical neoplasia over time, from a baseline of normal cervical cytology.

Methods:This paper presents the follow up data from a previous cross sectional analysis. Women from a screening population who had normal cytology and who were HR-HPV positive were recalled after two to three years for cytology and HPV genotyping. The development of cervical neoplasia at follow up was related to the course of HPV infection (clearance, persistence, or sequential infection) and the presence of single or multiple HPV infections at baseline. A comparator control group of women who were HPV and cytologically negative at baseline were selected from the same population.

Results:Twelve cases of dyskaryosis were found in women who were HPV positive at baseline; four were high grade. Only three cases of low grade dyskaryosis were found in the control group. Women with type specific persistent infections were significantly more likely to develop cervical neoplasia than women who cleared the infection (p = 0.0001) or were sequentially infected with different types (p = 0.001). Women with multiple HPV infections at baseline were no more likely to develop cervical dyskaryosis than those with a single infection.

Conclusions:Type specific persistent HR-HPV infection as monitored by genotyping can identify women at increased risk of cervical neoplasia more accurately than a single or repeated presence/absence HPV test. The cost effectiveness of such an approach should be investigated by an appropriate, large scale cost–benefit analysis.
New approaches for genotyping paraffin wax embedded breast tissue from patients with cancer: the Iowa women’s health study
Authors: Thyagarajan B , Anderson K E , Kong F , Selk F R , Lynch C F , Gross M D
Published: August 2005

Background:The use of paraffin wax embedded tissue samples as a source of DNA for genotype analysis has been limited because of difficulties in DNA extraction and single nucleotide polymorphism (SNP) analysis.

Aims:To test the feasibility of applying the combination of a commonly used DNA isolation procedure, PureGene, and a high throughput SNP analysis method, the polymerase chain reaction (PCR)-INVADER assay, to genotype several types of paraffin wax embedded breast tissues.

Methods:Twenty formalin fixed, paraffin wax blocks were obtained from five participants in the Iowa women’s health study. Each participant provided several types of tissue including normal lymph node, normal nipple/areola tissue, inflammatory/fibrotic breast tissue, or normal breast tissue, and tumour tissue.

Results:Good quality DNA (260/280 ratio >1.6) was obtained from all tissues. Normal lymph nodes yielded the largest amount of DNA (97.1 μg). DNA obtained from the samples was tested for a germline C1183T polymorphism in the MnSOD gene by three methods—PCR-RFLP (restriction fragment length polymorphism), INVADER assay, and PCR-INVADER assay. Of the 20 samples, PCR-RFLP genotyped 16, the PCR-INVADER assay 18, and the INVADER assay two. This methodology was then used to analyse five additional genotypes and confirmed the general applicability of the method.

Conclusions:This study demonstrated the feasibility of (1) using several paraffin wax embedded breast tissues as a source of DNA for germline genetic analysis, with lymph nodes providing the highest yield, and (2) using the combination of a common extraction method with a high throughput SNP analysis method, the PCR–INVADER assay.