bluuebunny/crossref_metadata_2025 huggingface dataset:
Antifolate Activity of Epigallocatechin Gallate against
Stenotrophomonas maltophilia
Authors: Navarro-Martínez María Dolores , Navarro-Perán Enma , Cabezas-Herrera Juan , Ruiz-Gómez Joaquín , García-Cánovas Francisco , Rodríguez-López José Neptuno
Published: June 2005

The catechin epigallocatechin gallate, one of the main constituents of green tea, showed strong antibiotic activity against 18 isolates of
Stenotrophomonas maltophilia
(MIC range, 4 to 256 μg/ml). In elucidating its mechanism of action, we have shown that epigallocatechin gallate is an efficient inhibitor of
S. maltophilia
dihydrofolate reductase, a strategic enzyme that is considered an attractive target for the development of antibacterial agents. The inhibition of
S. maltophilia
dihydrofolate reductase by this tea compound was studied and compared with the mechanism of a nonclassical antifolate compound, trimethoprim. Investigation of dihydrofolate reductase was undertaken with both a trimethoprim-susceptible
S. maltophilia
isolate and an isolate with a high level of resistance. The enzymes were purified using ammonium sulfate precipitation, gel filtration, and methotrexate affinity chromatography. The two isolates showed similar levels of dihydrofolate reductase expression and similar substrate kinetics. However, the dihydrofolate reductase from the trimethoprim-resistant isolate demonstrated decreased susceptibility to inhibition by trimethoprim and epigallocatechin gallate. As with other antifolates, the action of epigallocatechin gallate was synergistic with that of sulfamethoxazole, a drug that blocks folic acid metabolism in bacteria, and the inhibition of bacterial growth was attenuated by including leucovorin in the growth medium. We conclude that the mechanism of action of epigallocatechin gallate on
S. maltophilia
is related to its antifolate activity.
Antimicrobial Peptide Therapeutics for Cystic Fibrosis
Authors: Zhang Lijuan , Parente Jody , Harris Scott M. , Woods Donald E. , Hancock Robert E. W. , Falla Timothy J.
Published: June 2005

Greater than 90% of lung infections in cystic fibrosis (CF) patients are caused by
Pseudomonas aeruginosa
, and the majority of these patients subsequently die from lung damage. Current therapies are either targeted at reducing obstruction, reducing inflammation, or reducing infection. To identify potential therapeutic agents for the CF lung, 150 antimicrobial peptides consisting of three distinct structural classes were screened against mucoid and multidrug-resistant clinical isolates of
P. aeruginosa
,
Stenotrophomonas maltophilia
,
Achromobacter xylosoxidans
, and
Staphylococcus aureus
. Five peptides that retained potent antimicrobial activities in physiological salt and divalent cation environment were further characterized in vivo using a rat chronic lung infection model. All animals were inoculated intratracheally with 10
4
P. aeruginosa
mucoid PAO1 cells in agar beads. Three days following inoculation treatment was initiated. Animals were treated daily for 3 days with 100 μl of peptide solution (1 mg/ml) in 10 mM sodium citrate, which was deposited via either intratracheal instillation or aerosolization. Control animals received daily exposure to vehicle alone. At the end of the treatment the lungs of the animals were removed for quantitative culture. Four peptides, HBCM2, HBCM3, HBCPα-2, and HB71, demonstrated significant reduction in
Pseudomonas
bioburden in the lung of rats. Further in vivo studies provided direct evidence that anti-inflammatory activity was associated with three of these peptides. Therefore, small bioactive peptides have the potential to attack two of the components responsible for the progression of lung damage in the CF disease: infection and inflammation.
Evaluation of a New Line Probe Assay for Rapid Identification of
gyrA
Mutations in
Mycobacterium tuberculosis
Authors: Giannoni Federico , Iona Elisabetta , Sementilli Federica , Brunori Lara , Pardini Manuela , Migliori Giovanni Battista , Orefici Graziella , Fattorini Lanfranco
Published: June 2005

Resistance of
Mycobacterium tuberculosis
to fluoroquinolones (FQ) results mostly from mutations in the
gyrA
gene. We developed a reverse hybridization-based line probe assay in which oligonucleotide probes carrying the wild-type
gyrA
sequence, a serine-to-threonine (S95T) polymorphism, and
gyrA
mutations (A90V, A90V-S95T, S91P, S91P-S95T, D94A, D94N, D94G-S95T, D94H-S95T) were immobilized on nitrocellulose strips and hybridized with digoxigenin-labeled PCR products obtained from
M. tuberculosis
strains. When a mutated PCR product was used, hybridization occurred to the corresponding mutated probe but not to the wild-type probe. A panel of
M. tuberculosis
complex strains including 19 ofloxacin-resistant (OFL-R) and 9 ofloxacin-susceptible (OFL-S)
M. tuberculosis
strains was studied for detection and identification of
gyrA
mutations by the line probe assay and nucleotide sequencing, in comparison with testing of in vitro susceptibility to FQ. Results were 100% concordant with those of nucleotide sequencing. The S95T polymorphism, which is not related to FQ resistance, was found in 5 OFL-S and 2 OFL-R strains; the other 17 OFL-R strains harbored single mutations associated with serine or threonine at codon 95. No mutations were found in the other OFL-S strains. Overall, on the basis of the MICs on solid medium, the new line probe assay correctly identified all OFL-S and 17 out of 19 (89.5%) OFL-R strains. A nested-PCR protocol was also evaluated for the assay to amplify PCR products from
M. tuberculosis
-spiked sputa, with a good specificity and a sensitivity of 2 × 10
3
M. tuberculosis
CFU per ml of sputum.
Phage P68 Virion-Associated Protein 17 Displays Activity against Clinical Isolates of
Staphylococcus aureus
Authors: Takáč Marian , Bläsi Udo
Published: June 2005

Phage-encoded murein hydrolases are either part of the lysis cassette or found as structural components of the phage virion. Here, we show that
Staphylococcus aureus
bacteriophage P68 contains a virion-associated muralytic enzyme. Protein 17 has a composite structure. The N-terminal part comprises the muralytic activity, whereas the C-terminal part is required for binding to the cell surface. A high multiplicity of infection with phage P68 caused rapid lysis, and purified protein 17 triggered premature lysis when added to
S. aureus
cells prior to infection with P68, suggesting that it functions to weaken the murein at the site of phage DNA entry. Protein 17 displayed activity against clinical
S. aureus
isolates, which are resistant to infection by phage P68, demonstrating that the protein targets surface structures distinct from the phage receptor. This broad activity spectrum of protein 17 could qualify virion-associated muralytic enzymes as attractive antimicrobials.
Identification of a New Allelic Variant of theAcinetobacter baumanniiCephalosporinase, ADC-7 β-Lactamase: Defining a Unique Family of Class C Enzymes
Authors: Hujer Kristine M. , Hamza Nashaat S. , Hujer Andrea M. , Perez Federico , Helfand Marion S. , Bethel Christopher R. , Thomson Jodi M. , Anderson Vernon E. , Barlow Miriam , Rice Louis B. , Tenover Fred C. , Bonomo Robert A.
Published: June 2005

Acinetobacterspp. are emerging as opportunistic hospital pathogens that demonstrate resistance to many classes of antibiotics. In a metropolitan hospital in Cleveland, a clinical isolate ofAcinetobacter baumanniithat tested resistant to cefepime and ceftazidime (MIC = 32 μg/ml) was identified. Herein, we sought to determine the molecular basis for the extended-spectrum-cephalosporin resistance. Using analytical isoelectric focusing, a β-lactamase with a pI of ≥9.2 was detected. PCR amplification with specificA. baumanniicephalosporinase primers yielded a 1,152-bp product which, when sequenced, identified a novel 383-amino-acid class C enzyme. Expressed inEscherichia coliDH10B, this β-lactamase demonstrated greater resistance against ceftazidime and cefotaxime than cefepime (4.0 μg/ml versus 0.06 μg/ml). The kinetic characteristics of this β-lactamase were similar to other cephalosporinases found inAcinetobacterspp. In addition, this cephalosporinase was inhibited by meropenem, imipenem, ertapenem, and sulopenem (Ki< 40 μM). The amino acid compositions of this novel enzyme and other class C β-lactamases thus far described forA. baumannii,Acinetobactergenomic species 3, andOligella urethralisin Europe and South Africa suggest that this cephalosporinase defines a unique family of class C enzymes. We propose a uniform designation for this family of cephalosporinases (Acinetobacter-derivedcephalosporinases [ADC]) found inAcinetobacterspp. and identify this enzyme as ADC-7 β-lactamase. The coalescence ofAcinetobacter ampCβ-lactamases into a single common ancestor and the substantial phylogenetic distance separating them from otherampCgenes support the logical value of developing a system of nomenclature for theseAcinetobactercephalosporinase genes.
Worldwide Disseminated
armA
Aminoglycoside Resistance Methylase Gene Is Borne by Composite Transposon Tn
1548
Authors: Galimand M. , Sabtcheva S. , Courvalin P. , Lambert T.
Published: June 2005

The
armA
(
a
minoglycoside
r
esistance
m
ethylase) gene, which confers resistance to 4,6-disubstituted deoxystreptamines and fortimicin, was initially found in
Klebsiella pneumoniae
BM4536 on IncL/M plasmid pIP1204 of ca. 90 kb which also encodes the extended-spectrum β-lactamase CTX-M-3. Thirty-four enterobacteria from various countries that were likely to produce a CTX-M enzyme since they were more resistant to cefotaxime than to ceftazidime were studied. The
armA
gene was detected in 12 clinical isolates of
Citrobacter freundii
,
Enterobacter cloacae
,
Escherichia coli
,
K. pneumoniae
,
Salmonella enterica
, and
Shigella flexneri
, in which it was always associated with
bla
CTX-M-3
on an IncL/M plasmid. Conjugation, analysis of DNA sequences, PCR mapping, and plasmid conduction experiments indicated that the
armA
gene was part of composite transposon Tn
1548
together with genes
ant3"9
,
sul1
, and
dfrXII
, which are responsible for resistance to streptomycin-spectinomycin, sulfonamides, and trimethoprim, respectively. The 16.6-kb genetic element was flanked by two copies of IS
6
and migrated by replicative transposition. This observation accounts for the presence of
armA
on self-transferable plasmids of various incompatibility groups and its worldwide dissemination. It thus appears that posttranscriptional modification of 16S rRNA confers high-level resistance to all the clinically available aminoglycosides except streptomycin in gram-negative human and animal pathogens.
Mechanisms of Resistance to Imipenem and Ampicillin in
Enterococcus faecalis
Authors: Ono Seiji , Muratani Tetsuro , Matsumoto Tetsuro
Published: June 2005

We found ampicillin- and imipenem-resistant isolates of
vanA
-possessing
Enterococcus faecalis
with MICs of 8 to 16 μg/ml and 4 to 32 μg/ml, respectively. There have been few reports about penicillin- and imipenem-resistant
E. faecalis
. Two mechanisms of beta-lactam resistance in
E. faecalis
, the production of beta-lactamase and the overproduction of penicillin-binding proteins (PBPs), have been reported. The resistant isolates in the current study did not produce any beta-lactamases and analysis of the PBPs showed no overproduction. However, the affinities of PBP4 for beta-lactams in the resistant strains were lower than those of susceptible strains but the affinities of other PBPs for beta-lactams did not change. Accordingly, whole
pbp4
fragments from these resistant isolates were sequenced. Two amino acid substitutions at positions 520 and 605 were observed in the highly resistant strains compared to the susceptible ones, Pro520Ser and Tyr605His, and a single Tyr605His amino acid substitution was found in the low-resistance strains. These two point mutations exist in the region between the active-site-defining motifs SDN and KTG of the penicillin-binding domain, the main target of beta-lactams. A strong correlation was seen between these substitutions and decreasing affinities of PBP4 to beta-lactams. In
E. faecalis
, resistance due to mutations in PBPs has not been reported, though it has in
Enterococcus faecium
. Our results suggest that development of high-level resistance to penicillins and imipenem depends on point mutations of PBP4 at positions 520 and 605.
In Vitro Synergy of Ciprofloxacin and Gatifloxacin against Ciprofloxacin-Resistant
Pseudomonas aeruginosa
Authors: Pankey George A. , Ashcraft Deborah S.
Published: June 2005

Multidrug-resistant
Pseudomonas aeruginosa
with combined decreased susceptibility to ceftazidime, ciprofloxacin, imipenem, and piperacillin is increasingly being found as a cause of nosocomial infections. It is important to look for combinations of drugs that might be synergistic. Ciprofloxacin resistance by
P. aeruginosa
is mediated in part by an efflux pump mechanism. Gatifloxacin, an 8-methoxyfluoroquinolone, inhibits a staphylococcal efflux pump. An earlier in vitro study using an Etest synergy method and time-kill assay suggested synergy of ciprofloxacin and gatifloxacin against
P. aeruginosa
. Synergy testing was performed by Etest and time-kill assay for 31 clinically unique, plasmid DNA distinct, U.S.
P. aeruginosa
isolates. Etest MICs for ciprofloxacin were 4 to >32 μg/ml, and for gatifloxacin they were >32 μg/ml. Ciprofloxacin plus gatifloxacin showed synergy by the Etest method for 6 (19%) of the 31
P. aeruginosa
isolates using a summation fractional inhibitory concentration of ≤0.5 for synergy. Synergy was demonstrated for 13/31 (42%) of isolates by time-kill assay. No antagonism was detected. The remaining isolates were indifferent to the combination. The Etest method and time-kill assay were 65% (20/31) concordant. The mechanism of the in vitro synergy may include
P. aeruginosa
ciprofloxacin efflux pump inhibition by gatifloxacin.
Structural and Functional Study of the Phenicol-Specific Efflux Pump FloR Belonging to the Major Facilitator Superfamily
Authors: Braibant Martine , Chevalier Jacqueline , Chaslus-Dancla Elisabeth , Pagès Jean-Marie , Cloeckaert Axel
Published: June 2005

The florfenicol-chloramphenicol resistance gene
floR
from
Salmonella enterica
was previously identified and postulated to belong to the major facilitator (MF) superfamily of drug exporters. Here, we confirmed a computer-predicted transmembrane topological model of FloR, using the
phoA
gene fusion method, and classified this protein in the DHA12 family (containing 12 transmembrane domains) of MF efflux transporters. We also showed that FloR is a transporter specific for structurally associated phenicol drugs (chloramphenicol, florfenicol, thiamphenicol) which utilizes the proton motive force to energize an active efflux mechanism. By site-directed mutagenesis of specific charged residues belonging to putative transmembrane segments (TMS), two residues essential for active efflux function, D23 in TMS1 and R109 in TMS4, were identified. Of these, the acidic residue D23 seems to participate directly in the affinity pocket involved in phenicol derivative recognition. A third residue, E283 in TMS9, seems to be necessary for correct membrane folding of the transporter.
Peptides Selected for Binding to a Virulent Strain of
Haemophilus influenzae
by Phage Display Are Bactericidal
Authors: Bishop-Hurley Sharon L. , Schmidt Francis J. , Erwin Alice L. , Smith Arnold L.
Published: June 2005

Nontypeable
Haemophilus influenzae
(NTHi) is an obligate parasite of the oropharynx of humans, in whom it commonly causes mucosal infections such as otitis media, sinusitis, and bronchitis. We used a subtractive phage display approach to affinity select for peptides binding to the cell surface of a novel invasive NTHi strain R2866 (also called Int1). Over half of the selected phage peptides tested were bactericidal toward R2866 in a dose-dependent manner. Five of the clones encoded the same peptide sequence (KQRTSIRATEGCLPS; clone hi3/17), while the remaining four clones encoded unique peptides. All of the bactericidal phage peptides but one were cationic and had similar physical-chemical properties. Clone hi3/17 possessed a similar level of activity toward a panel of clinical NTHi isolates and
H. influenzae
type b strains but lacked bactericidal activity toward gram-positive (
Enterococcus faecalis
,
Staphylococcus aureus
) and gram-negative (
Proteus mirabilis
,
Pseudomonas aeruginosa
, and
Salmonella enterica
) bacteria. These data indicate that peptides binding to bacterial surface structures isolated by phage display may prove of value in developing new antibiotics.
Antimalarial Activity of Human Immunodeficiency Virus Type 1 Protease Inhibitors
Authors: Parikh Sunil , Gut Jiri , Istvan Eva , Goldberg Daniel E. , Havlir Diane V. , Rosenthal Philip J.
Published: June 2005

Aspartic proteases play key roles in the biology of malaria parasites and human immunodeficiency virus type 1 (HIV-1). We tested the activity of seven HIV-1 protease inhibitors against cultured
Plasmodium falciparum
. All compounds inhibited the development of parasites at pharmacologically relevant concentrations. The most potent compound, lopinavir, was active against parasites (50% inhibitory concentration [IC
50
], 0.9 to 2.1 μM) at concentrations well below those achieved by ritonavir-boosted lopinavir therapy. Lopinavir also inhibited the
P. falciparum
aspartic protease plasmepsin II at a similar concentration (IC
50
, 2.7 μM). These findings suggest that use of HIV-1 protease inhibitors may offer clinically relevant antimalarial activity.
The Macrolide Roxithromycin Impairs NADPH Oxidase Activation and Alters Translocation of Its Cytosolic Components to the Neutrophil Membrane In Vitro
Authors: Abdelghaffar Houria , Babin-Chevaye Catherine , Labro Marie-Thérèse
Published: June 2005

We have studied the interference of roxithromycin with NADPH oxidase, the key enzymatic system for oxidant production by human neutrophils. Roxithromycin alters the reconstitution of an active enzyme and impairs the translocation to the outer membrane of the cytosolic components p47-phox and p67-phox. Interestingly, in resting cells roxithromycin directly triggers the translocation of these factors without stimulating the oxidative burst.
In Vitro Interactions of Micafungin with Other Antifungal Drugs against Clinical Isolates of Four Species of
Cryptococcus
Authors: Serena Carolina , Fernández-Torres Belkys , Pastor F. Javier , Trilles Luciana , Lazéra Márcia dos Santos , Nolard Nicole , Guarro Josep
Published: June 2005

The combination of micafungin (MFG) with amphotericin B (AMB), fluconazole, itraconazole, voriconazole, or ravuconazole was evaluated against 37 strains of four species of
Cryptococcus
by the checkerboard method. Antagonism was never seen. Synergy was observed for some isolates for each combination and was most frequent with MFG-AMB.
In Vitro Antimicrobial Susceptibility Testing of
Helicobacter felis
,
H. bizzozeronii
, and
H. salomonis
Authors: Van den Bulck K. , Decostere A. , Gruntar I. , Baele M. , Krt B. , Ducatelle R. , Haesebrouck F.
Published: June 2005

The susceptibilities of
Helicobacter felis
(15 strains),
H. bizzozeronii
(7 strains), and
H. salomonis
(3 strains) to 10 antimicrobial agents were investigated by determination of the MIC using the agar dilution method. No consistent differences were noticed between the different
Helicobacter
species, which were all highly susceptible to ampicillin, clarithromycin, tetracycline, tylosin, enrofloxacin, gentamicin, and neomycin, as demonstrated by low MICs. Higher MICs were obtained for lincomycin (up to 8 μg/ml) and spectinomycin (up to 4 μg/ml). Two
H. felis
strains showed a MIC of 16 μg/ml for metronidazole, suggesting acquired resistance to this antimicrobial agent.
Broader Distribution of Plasmid-Mediated Quinolone Resistance in the United States
Authors: Robicsek A. , Sahm D. F. , Strahilevitz J. , Jacoby G. A. , Hooper D. C.
Published: June 2005

The plasmid-encoded quinolone resistance gene
qnrA
confers low-level quinolone resistance, facilitating selection of higher-level resistance. Epidemiologic surveys for
qnrA
were extended to isolates of
Enterobacter
spp. and to quinolone-susceptible
Enterobacteriaceae
. Two (10%) of 20 ceftazidime-resistant quinolone-susceptible
Klebsiella pneumoniae
strains carried the gene, as did 12 (17%) of 71 ceftazidime-resistant
Enterobacter
strains from across the United States. One of these
Enterobacter
isolates was quinolone susceptible. Thus,
qnrA
is present in quinolone-resistant and quinolone-susceptible
Enterobacter
and
Klebsiella
strains in the United States.
Production of Enterocin P, an Antilisterial Pediocin-Like Bacteriocin from
Enterococcus faecium
P13, in
Pichia pastoris
Authors: Gutiérrez Jorge , Criado Raquel , Martín María , Herranz Carmen , Cintas Luis M. , Hernández Pablo E.
Published: June 2005

The gene encoding mature enterocin P (EntP), an antimicrobial peptide from
Enterococcus faecium
P13, was cloned into the pPICZαA expression vector to generate plasmid pJC31. This plasmid was integrated into the genome of
P. pastoris
X-33, and EntP was heterologously secreted from the recombinant
P. pastoris
X-33t
1
derivative at a higher production and antagonistic activity than from
E. faecium
P13.
Compound Efflux in
Helicobacter pylori
Authors: Kutschke Amy , de Jonge Boudewijn L. M.
Published: June 2005

Susceptibility testing with a variety of structurally unrelated compounds showed that
hefC
in
Helicobacter pylori
is involved in multidrug efflux. This efflux was shown to depend on the proton motive force, as demonstrated by ethidium bromide accumulation experiments. Thus,
H. pylori
contains an active multidrug efflux mechanism.
Time-Kill Study of the Activity of Telithromycin against Macrolide-Resistant
Streptococcus pneumoniae
Isolates with 23S rRNA Mutations and Changes in Ribosomal Proteins L4 and L22
Authors: Reinert Ralf René , Al-Lahham Adnan
Published: June 2005

By use of a time-kill methodology, the antipneumococcal activity of telithromycin was determined against macrolide-resistant
S. pneumoniae
isolates having mutations in the 23S rRNA gene and changes in the ribosomal proteins L4 and L22. Telithromycin had MICs ranging between 0.03 and 0.25 μg/ml and was bactericidal against four of seven strains after 24 h at two times the MIC.
Transcriptional Analysis of the
bla
CTX-M-2
Gene in
Salmonella enterica
Serovar Infantis
Authors: Di Conza José A. , Gutkind Gabriel O. , Mollerach Marta E. , Ayala Juan A.
Published: June 2005

Transcriptional organization of
bla
CTX-M-2
present in a multiresistance plasmid of
Salmonella enterica
serovar Infantis suggests the presence of more than one promoter involved in the expression of the β-lactamase gene. At least two
bla
CTX-M-2
-specific mRNAs (near to 1 kb and 5 kb) were evidenced. Two +1 signals were detected at −22 bp and −59 bp of
bla
CTX-M-2
defining two putative promoters.
Emergence of KPC-Possessing
Klebsiella pneumoniae
in Brooklyn, New York: Epidemiology and Recommendations for Detection
Authors: Bratu Simona , Mooty Mohamad , Nichani Satyen , Landman David , Gullans Carl , Pettinato Barbara , Karumudi Usha , Tolaney Pooja , Quale John
Published: June 2005

Among 257 isolates of
Klebsiella pneumoniae
collected in Brooklyn, NY, 24% were found to possess
bla
KPC
. Clinical microbiology laboratories that used automated broth microdilution systems reported 15% of the KPC-possessing isolates as susceptible to imipenem. The imipenem MIC was found to be markedly affected by the inoculum. For accurate detection of KPC-possessing
K. pneumoniae
, particular attention should be paid to proper inoculum preparation for broth-based susceptibility methods. In addition, using ertapenem or meropenem for class reporting of carbapenem susceptibility will improve detection.
Progressive Increase in Antimicrobial Resistance among Invasive Isolates of
Haemophilus influenzae
Obtained from Children Admitted to a Hospital in Kilifi, Kenya, from 1994 to 2002
Authors: Scott J. Anthony G. , Mwarumba Salim , Ngetsa Caroline , Njenga Salome , Lowe Brett S. , Slack Mary P. E. , Berkley James A. , Mwangi Isaiah , Maitland Kathryn , English Mike , Marsh Kevin
Published: June 2005

Etest susceptibilities to amoxicillin, chloramphenicol, and trimethoprim-sulfamethoxazole of 240 invasive isolates of
Haemophilus influenzae
cultured from children in rural Kenya were 66%, 66%, and 38%, respectively. Resistance increased markedly over 9 years and was concentrated among serotype b isolates. In Africa, the increasing cost of treating resistant infections supports economic arguments for prevention through conjugate
H. influenzae
type b immunization.
In Vitro and In Vivo Bactericidal Activities of Vancomycin Dispersed in Porous Biodegradable Poly(ε-Caprolactone) Microparticles
Authors: Le Ray Anne-Marie , Gautier Hélène , Laty Marie-Katel , Daculsi Guy , Merle Christian , Jacqueline Cédric , Hamel Antoine , Caillon Jocelyne
Published: June 2005

Treatment of methicillin-resistantStaphylococcus aureusosteomyelitis requires a prolonged antibiotic therapy with vancomycin. Because of its weak diffusion, the in situ implantation of vancomycin could be interesting. The activity of vancomycin encapsulated in microparticles was evaluated in vitro and in vivo on rabbit osteomyelitis and showed a good activity compared to intravenous administration.
Efficacy of Nebulized Liposomal Amphotericin B in Treatment of Experimental Pulmonary Aspergillosis
Authors: Gavaldà Joan , Martín María-Teresa , López Pedro , Gomis Xavier , Ramírez José-Luís , Rodríguez Dolors , Len Oscar , Puigfel Yolanda , Ruíz Isabel , Pahissa Albert
Published: June 2005

The efficacy of therapeutic aerosolized amphotericin B (AMB) was studied in a steroid-immunosuppressed murine model of invasive pulmonary aspergillosis. Nebulized liposomal AMB can be a valid approach to the treatment of this infection, with subjects showing significantly improved survival relative to that of subjects given intravenous deoxycholate AMB, as well as lower lung weights and pulmonary glucosamine levels.
Predominance of 23S rRNA Mutants among Non-Erm, Non-Mef Macrolide-Resistant Clinical Isolates of
Streptococcus pneumoniae
Collected in the United States in 1999-2000
Authors: Davies Todd A. , Bush Karen , Sahm Daniel , Evangelista Alan
Published: June 2005

A total of 322 erythromycin-resistant pneumococci from TRUST 3 and TRUST 4 United States surveillance studies (1999-2000) were screened for 23S rRNA, L4, and L22 gene mutations. Nineteen isolates, two with
mefA
, had mutations at position 2058 or 2059 in 23S rRNA. Two had a
69
GTG
71
-to-TPS substitution in L4; one of these also contained
ermA
.
InVitro Antibacterial Activity of DX-619, a Novel Des-Fluoro(6) Quinolone
Authors: Fujikawa Katsuko , Chiba Megumi , Tanaka Mayumi , Sato Kenichi
Published: June 2005

The
in vitro activities of DX-619, des-fluoro(6) quinolone, against 1,208
clinical isolates were examined. DX-619 was particularly potent against
staphylococci, including ciprofloxacin- and methicillin-resistant
strains; the MIC at which 90% of the strains tested were inhibited was
0.5 μg/ml. In addition, DX-619 was also active against
gram-negative
bacteria.
Novel Spectinomycin/Streptomycin Resistance Gene,
aadA14
, from
Pasteurella multocida
Authors: Kehrenberg Corinna , Catry Boudewijn , Haesebrouck Freddy , de Kruif Aart , Schwarz Stefan
Published: June 2005

A novel spectinomycin/streptomycin resistance gene, designated
aadA14
, was detected on the mobilizable 5,198-bp plasmid pCCK647 from
Pasteurella multocida
. The
aadA14
gene encodes an aminoglycoside adenylyltransferase of 261 amino acids. Sequence comparisons revealed that the AadA14 protein showed less than 60% identity to the AadA proteins known so far.
Interaction of the Plasmid-Encoded Quinolone Resistance Protein QnrA with
Escherichia coli
Topoisomerase IV
Authors: Tran John H. , Jacoby George A. , Hooper David C.
Published: June 2005

Purified QnrA blocked ciprofloxacin inhibition of topoisomerase IV, just as QnrA was previously found to prevent quinolone inhibition of DNA gyrase. With a gel displacement assay, tagged QnrA was shown to bind to topoisomerase IV and its subunits in a reaction that did not depend on the presence of DNA, quinolone, or ATP.
Prevention of the Cryptic Epitope SLAYGLR within Osteopontin Does Not Influence Susceptibility to
Candida albicans
Infection
Authors: Sato Ikuko , Yamamoto Nobuchika , Yamazaki Harumi , Hashimoto Seiji , Hino Motohiro , Sakai Fumihiko , Fujie Akihiko
Published: June 2005

The effect of an antiosteopontin antibody (M5 Ab) reacting with the SLAYGLR sequence within osteopontin on the host susceptibility to infection was investigated in a murine model of disseminated candidiasis. The treatment with anti-tumor necrosis factor alpha antibody enhanced fungal infection, while the treatment with M5 Ab did not affect the infection.
In Vitro Activities of Levofloxacin and Comparable Agents against Middle Ear Fluid, Nasopharyngeal, and Oropharyngeal Pathogens Obtained from Costa Rican Children with Recurrent Otitis Media or Failing Other Antibiotic Therapy
Authors: Soley Carolina , Arguedas Adriano , Porras Wendy , Guevara Silvia , Loaiza Cecilia , Pérez Alexandra , Rincón Guillermo , Schultz Malka , Arguedas Jorge , Brilla Roberto
Published: June 2005

This study analyzes the in vitro activities of levofloxacin and other commonly used antimicrobials against middle ear fluid, nasopharyngeal, and oropharyngeal pathogens obtained from children with otitis media at risk of having a resistant pathogen. Levofloxacin proved to be very active against these pathogens and had intermediate activity against
Streptococcus pyogenes
.
Induction of Telithromycin Resistance by Erythromycin in Isolates of Macrolide-Resistant
Staphylococcus
spp
Authors: Davis Kepler A. , Crawford Sharon A. , Fiebelkorn Kristin R. , Jorgensen James H.
Published: June 2005

Staphylococcal isolates were examined for possible macrolide-inducible resistance to telithromycin. All macrolide-resistant isolates demonstrated telithromycin D-shaped zones. This result did not discriminate between resistance due to an efflux mechanism (
msrA
) or a ribosomal target modification (
ermA
or
ermC
). Inducible telithromycin resistance in staphylococci does not appear to be analogous to inducible clindamycin resistance.
Integron-Associated Antibiotic Resistance and Phylogenetic Grouping of
Escherichia coli
Isolates from Healthy Subjects Free of Recent Antibiotic Exposure
Authors: Skurnik David , Le Menac'h Arnaud , Zurakowski David , Mazel Didier , Courvalin Patrice , Denamur Erick , Andremont Antoine , Ruimy Raymond
Published: June 2005

The study of integrons in 181
Escherichia coli
isolates from three groups of healthy subjects who lived in communities and had not taken antibiotics for at least 1 month showed that the presence of integrons was associated with antibiotic resistance and phylogenetic grouping of the bacterial host and dependent on a subject's living environment.
Survey of
Enterobacteriaceae
Producing Extended-Spectrum β-Lactamases in a Slovak Hospital: Dominance of SHV-2a and Characterization of TEM-132
Authors: Zarnayová Martina , Siebor Eliane , Péchinot André , Duez Jean-Marie , Bujdáková Helena , Labia Roger , Neuwirth Catherine
Published: June 2005

Eighty-five extended-spectrum β-lactamase-producing
Enterobacteriaceae
from a Slovak hospital have been studied. SHV-2a was predominant, but other variants have been detected, namely, SHV-5, SHV-12, TEM-12, TEM-15, and TEM-132, which differed from TEM-1 by amino acid substitutions R164H, E240K, and I173V and had kinetic properties similar to those of TEM-28.
Differences in the DNA Sequences in the Upstream Attenuator Region of
erm
(A) in Clinical Isolates of
Streptococcus pyogenes
and Their Correlation with Macrolide/Lincosamide Resistance
Authors: Doktor Stella Z. , Shortridge Virginia
Published: June 2005

The regulatory regions of 52
erm
(A) [formerly
erm
(TR)] clinical
Streptococcus pyogenes
isolates were studied. Differences in the upstream regulatory region of
erm
(A) correlated with macrolide/lincosamide resistance patterns. Nine macrolide/lincosamide/streptogramin B-resistant isolates had changes in the leader sequence of
erm
(A) including base changes, insertions, or deletions. Isolates were also
emm
typed.
Molecular Characterization of Glycopeptide-Resistant
Enterococcus faecium
Isolates from Portuguese Hospitals
Authors: Novais Carla , Sousa João C. , Coque Teresa M. , Peixe Luísa V. ,   The Portuguese Resistance Study Group
Published: June 2005

Fifty-one pulsed-field gel electrophoresis types and 17 Tn
1546
variants were identified among 101
Enterococcus faecium
isolates recovered in three distant Portuguese hospitals. Intra- and interhospital dissemination of specific strains and Tn
1546
types was detected, which might largely contribute to the endemicity of vancomycin-resistant
E. faecium
in Portuguese hospitals, as happened previously in other geographical locations.
Heterogeneity of Genotype-Phenotype Correlation among Macrolide-Resistant
Streptococcus agalactiae
Isolates
Authors: von Both Ulrich , Buerckstuemmer Anna , Fluegge Kirsten , Berner Reinhard
Published: June 2005

Seventy-four erythromycin-resistant group B
Streptococcus
isolates were analyzed regarding their phenotype-genotype and phenotype-serotype correlation. Four different phenotypes were assessed, one of them for the first time.
ermB
and
ermTR
were the most frequent genotypes (80%). The most prevalent serotype III showed great phenotypic variability while serotype V was strongly associated only with two different phenotypes.
Sublethal Concentrations of Ciprofloxacin Induce Bacteriocin Synthesis in
Escherichia coli
Authors: Jerman Borut , Butala Matej , Žgur-Bertok Darja
Published: June 2005

Antibiotics that interfere with DNA replication, as well as cell wall synthesis, induce the SOS response. In this report, we show that ciprofloxacin induces synthesis of colicins, narrow-spectrum antibiotics frequently produced by
Escherichia coli
strains, in an SOS-dependent manner.
Association of Plasmid-Mediated Quinolone Resistance with Extended-Spectrum β-Lactamase VEB-1
Authors: Poirel Laurent , Van De Loo Marc , Mammeri Hedi , Nordmann Patrice
Published: June 2005

Association of the plasmid-mediated quinolone resistance determinant QnrA and the
bla
VEB-1
gene was identified in a single
Enterobacter cloacae
isolate from K.-Bicêtre, France, and in 11 out of 23
bla
VEB-1
-positive enterobacterial isolates from Bangkok, Thailand. This result may explain in part the association between quinolone and extended-spectrum β-lactam resistance.
VAGUE RINGS
Authors: CRIST RANDALL , MORDESON JOHN N.
Published: June 2005

We examine the notion of a vague ring. We develop a method of constructing vague rings which can be used in the construction of other algebraic structures. We make a connection between vague rings and M-adic topologies on rings and also to the solution of nonlinear systems of equations and to the convergence of Cauchy sequences in power series rings. We introduce the notion of Ω-vagueness which we apply to the integration and differentiation of fuzzy functions.
IN VIVO IMAGING OF LYMPHOCYTE TRAFFICKING
Authors: Halin Cornelia , Rodrigo Mora J. , Sumen Cenk , von Andrian Ulrich H.
Published: June 2005

Over the past decades, intravital microscopy (IVM), the imaging of cells in living organisms, has become a valuable tool for studying the molecular determinants of lymphocyte trafficking. Recent advances in microscopy now make it possible to image cell migration and cell-cell interactions in vivo deep within intact tissues. Here, we summarize the principal techniques that are currently used in IVM, discuss options and tools for fluorescence-based visualization of lymphocytes in microvessels and tissues, and describe IVM models used to explore lymphoid and non-lymphoid organs. The latter will be introduced according to the physiologic itinerary of developing and differentiating T and B lymphocytes as they traffic through the body, beginning with their development in bone marrow and thymus and continuing with their migration to secondary lymphoid organs and peripheral tissues.
Inhibitor-κB kinase-β regulates LPS-induced TNF-α production in cardiac myocytes through modulation of NF-κB p65 subunit phosphorylation
Authors: Hall Gentzon , Singh Ishwar S. , Hester Lisa , Hasday Jeffery D. , Rogers Terry B.
Published: June 2005

TNF-α is recognized as a significant contributor to myocardial dysfunction. Although several studies suggest that members of the NF-κB family of transcription factors are essential regulators of myocardial TNF-α gene expression, recent developments in our understanding of the modulation of NF-κB activity through posttranslational modification of NF-κB subunits suggest that the present view of NF-κB-dependent cytokine expression in heart is incomplete. Therefore, the goal of the present study was to examine the role of p65 subunit phosphorylation in the regulation of TNF-α production in cultured neonatal ventricular myocytes. Bacterial LPS-induced TNF-α production is accompanied by a 12-fold increase in phosphorylation of p65 at Ser536, a modification associated with enhancement of p65 transactivation potential. Pharmacological inhibition of IKK-β reduced LPS-induced TNF-α production 38-fold, TNF-α mRNA levels 6-fold, and IκB-α phosphorylation 5-fold and degraded IκB-α 2-fold and p65 phosphorylation 6-fold. Overexpression of dominant-negative p65 reduced TNF-α production 3.5-fold, whereas overexpression of dominant-negative IKK-β reduced LPS-induced TNF-α production 2-fold and p65 phosphorylation 2-fold. Overexpression of dominant-negative IKK-α had no effect on p65 phosphorylation or TNF-α production, revealing that IKK-β, not IKK-α, plays a central role in regulation of p65 phosphorylation at Ser536and TNF-α production in heart. Finally, we demonstrated, using a chromatin immunoprecipitation assay, that LPS stimulates recruitment of Ser536-phosphorylated p65 to the TNF-α gene promoter in cardiac myocytes. Taken together, these data provide compelling evidence for the role of NF-κB signaling in TNF-α gene expression in heart and highlight the importance of this proinflammatory gene-regulatory pathway as a potential therapeutic target in the management of cytokine-induced myocardial dysfunction.
Relative contribution of Rho kinase and protein kinase C to myogenic tone in rat cerebral arteries in hypertension
Authors: Jarajapu Yagna P. R. , Knot Harm J.
Published: June 2005

Arterial smooth muscle constriction in response to pressure, i.e., myogenic tone, may involve calcium-dependent and calcium-sensitization mechanisms. Calcium sensitization in vascular smooth muscle is regulated by kinases such as PKC and Rho kinase, and activity of these kinases is known to be altered in cardiovascular disorders. In the present study, we evaluated the relative contribution of PKC and Rho kinase to myogenic tone in cerebral arteries in hypertension. Myogenic tone and arterial wall calcium in Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were measured simultaneously, and the effect of PKC and Rho kinase inhibitors on myogenic tone was evaluated. SHR arteries showed significantly greater myogenic tone than WKY arteries. Pressure/wall tension-arterial wall calcium curves showed a hyperbolic relation in WKY rats, but the curves for SHR arteries were parabolic. Myogenic tone was decreased by the Rho kinase inhibitors Y-27632 and HA-1077, with a significantly greater effect in SHR than in WKY arteries. Reduction in myogenic tone produced by the PKC inhibitor bisindolylmaleimide I in WKY and SHR arteries was significantly less than that produced by Rho kinase inhibition. The pressure-dependent increase in myogenic tone was significantly decreased by Y-27632, and the decrease was markedly greater than that produced by bisindolylmaleimide I in SHR arteries. In WKY arteries, the pressure-dependent increase in myogenic tone was decreased to a similar extent by Y-27632 and bisindolylmaleimide I. These results suggest greater myogenic tone with increased calcium sensitization in SHR arteries, largely because of Rho kinase activation, with a minor contribution of PKC activation.
Fas-associated death-domain protein inhibits TNF-α mediated NF-κB activation in cardiomyocytes
Authors: Chao Wei , Shen Yan , Li Ling , Zhao Huailong , Meiler Steffen E. , Cook Stuart A. , Rosenzweig Anthony
Published: June 2005

Fas-associated death-domain protein (FADD) is an adaptor molecule that links death receptors to caspase-8 in many cell types including cardiomyocytes (CMs). Although FADD has previously been reported to play an important role in CM apoptosis, the effect of FADD on CM NF-κB signaling, which is a proinflammatory pathway, has not been delineated. To investigate the role of FADD in CM NF-κB activation, we utilized adenoviral gene transfer of wild-type FADD and a truncation mutant that lacks the death-effector domain (FADD-DED) in rat CMs in vitro TNF-α activated NF-κB in CMs as demonstrated by phosphorylation and degradation of inhibitory-κB (IκB)-α-enhanced nuclear p65 and NF-κB DNA-binding activity as well as increased mRNA for the NF-κB-dependent adhesion molecule VCAM-1 (19 ± 4.1-fold) as measured by quantitative RT-PCR. Gene transfer of FADD inhibited TNF-α-induced IκB-α phosphorylation, decreased p65 nuclear translocation and NF-κB DNA-binding activity, and reduced VCAM-1 transcript levels by 53–65%. Interestingly, FADD-DED exhibited a similar but weaker inhibitory effect on NF-κB activation. The effects of FADD on NF-κB were cell-type specific. FADD expression also inhibited TNF-α-mediated NF-κB activation in human endothelial cells but not in rat pulmonary artery smooth muscle cells. In contrast, FADD expression actually activated NF-κB in human embryonic kidney (HEK)-293 cells. In CMs, FADD inhibited NF-κB activation as well as phosphorylation of IκB-α and IκB kinase (IKK)-β in response to cytokine stimulation or expression of the upstream kinases NF-κB-inducing kinase and IKK-β. These data demonstrate that FADD inhibits NF-κB activation in CMs, and this inhibition likely occurs at the level of phosphorylation and activation of IKK-β.
Surfactant protein D decreases pollen-induced IgE-dependent mast cell degranulation
Authors: Malherbe Delphine C. , Erpenbeck Veit J. , Abraham Soman N. , Crouch Erika C. , Hohlfeld Jens M. , Wright Jo Rae
Published: June 2005

Mast cells play a key role in allergy and asthma. They reside at the host-environment interface and are among the first cells to make contact with inhaled microorganisms and particulate antigens. Pulmonary surfactant proteins A and D (SP-A and SP-D) function in lung host defense by enhancing microbe phagocytosis and mediating other immune cell functions, but little is known about their effects on mast cells. We hypothesized that SP-A and/or SP-D modulate IgE-dependent mast cell functions. Pollen starch granules (PSG) extracted from Dactylis glomerata and coated with trinitrophenol (TNP) were used as a model of an inhaled organic particulate allergen. Our data revealed that SP-D inhibited by 50% the release of β-hexosaminidase by peritoneal mast cells sensitized with IgE anti-TNP and stimulated with TNP-PSG. In contrast, SP-A had no effect. Furthermore, SP-D aggregated PSG in a dose-dependent manner, and this aggregation was mediated by SP-D's carbohydrate recognition domain. A single arm SP-D mutant (RrSP-Dser15,20) neither aggregated PSG nor inhibited degranulation, suggesting that multimerization of SP-D is required for maximal PSG aggregation and inhibition of PSG-induced mast cell degranulation. This study is the first to demonstrate that SP-D modulates IgE-mediated mast cell functions, which are important in asthma and allergic inflammation.
Molecular imaging of lung glucose uptake after endotoxin in mice
Authors: Zhou Zhaohui , Kozlowski James , Goodrich Andrea L. , Markman Nathaniel , Chen Delphine L. , Schuster Daniel P.
Published: June 2005

Positron emission tomographic imaging after administration of the glucose analog fluorine-18 fluorodeoxyglucose ([18F]FDG) may be useful to study neutrophilic inflammation of the lungs. In this study, we sought to determine the specificity of the increase in lung [18F]FDG uptake after intraperitoneal endotoxin (Etx) for neutrophil influx into mouse lungs and to determine the regulation of glucose uptake after Etx by Toll-like receptors (TLRs) and TNF-α. Lung tissue radioactivity measurements by imaging were validated against counts in a gamma well counter. Glucose uptake was quantified as the [18F]FDG tissue-to-blood radioactivity ratio (TBR) after validating this measure against the “gold standard” measure of glucose uptake, the “net influx rate constant.” TBR measurements were made in a control group (no intervention), a group administered Etx, and a group administered Etx plus an additional agent (e.g., vinblastine) or Etx administered to a mutant mouse strain. The glucose uptake measurements were compared with measurements of myeloperoxidase. Increases in TBR after Etx were significantly but not completely eliminated by neutrophil depletion with vinblastine. Increases in TBR after Etx were consistent with signaling via either TLR-4 or TLR-2 (the latter probably secondary to peptidoglycan contaminants in Etx preparation) and were decreased by drug inhibition of TLR-4 but not by inhibition of TNF-α. Thus molecular imaging can be used to noninvasively monitor biological effects of Etx on lungs in mice, and changes in lung glucose uptake can be used to monitor effects of anti-inflammatory agents. Such imaging capacity provides a powerful new paradigm for translational “mouse-to-human” pulmonary research.
p38 and EGF receptor kinase-mediated activation of the phosphatidylinositol 3-kinase/Akt pathway is required for Zn2+-induced cyclooxygenase-2 expression
Authors: Wu Weidong , Silbajoris Robert A. , Whang Young E. , Graves Lee M. , Bromberg Philip A. , Samet James M.
Published: June 2005

Cyclooxygenase 2 (COX-2) expression is induced by physiological and inflammatory stimuli. Regulation of COX-2 expression is stimulus and cell type specific. Exposure to Zn2+has been associated with activation of multiple intracellular signaling pathways as well as the induction of COX-2 expression. This study aims to elucidate the role of intracellular signaling pathways in Zn2+-induced COX-2 expression in human bronchial epithelial cells. Inhibitors of the phosphatidylinositol 3-kinase (PI3K) potently block Zn2+-induced COX-2 mRNA and protein expression. Overexpression of adenoviral constructs encoding dominant-negative Akt kinase downstream of PI3K or wild-type phosphatase and tensin homolog deleted on chromosome 10, an important PI3K phosphatase, suppresses COX-2 mRNA expression induced by Zn2+. Zn2+exposure induces phosphorylation of the tyrosine kinases, including Src and EGF receptor (EGFR), and the p38 mitogen-activated protein kinase. Blockage of these kinases results in inhibition of Zn2+-induced Akt phosphorylation as well as COX-2 protein expression. Overexpression of dominant negative p38 constructs suppresses Zn2+-induced increase in COX-2 promoter activity. In contrast, the c-Jun NH2-terminal kinase and the extracellular signal-regulated kinases have minimal effect on Akt phosphorylation and COX-2 expression. Inhibition of p38, Src, and EGFR kinases with pharmacological inhibitors markedly reduces Akt phosphorylation induced by Zn2+. However, the PI3K inhibitors do not show inhibitory effects on p38, Src, and EGFR. These data suggest that p38 and EGFR kinase-mediated Akt activation is required for Zn2+-induced COX-2 expression and that the PI3K/Akt signaling pathway plays a central role in this event.