bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antibiotic Resistance in Bacteria Isolated from Subgingival Plaque in a Norwegian Population with Refractory Marginal Periodontitis
Authors: Handal Trude , Caugant Dominique A. , Olsen Ingar 
Published: March 2003

ABSTRACT

The prevalence of β-lactamase-producing bacteria in subgingival plaque from patients with refractory periodontitis in Norway was assessed by the chromogenic nitrocefin method. β-Lactamase activity was detected in 68% of the patients. Enzyme-producing strains belonged predominantly to the genus
Prevotella
; others were staphylococci, enteric gram-negative rods, and
Bacillus
spp.
In Vitro Activity of a New Antibiotic, NVP-PDF386 (VRC4887), against
Chlamydia pneumoniae
Authors: Roblin Patricia M. , Hammerschlag Margaret R. 
Published: March 2003

ABSTRACT

The in vitro activity of NVP-PDF386 (VRC4887), a novel new peptide deformylase inhibitor, and those of levofloxacin and clarithromycin were tested against 21 isolates of
Chlamydia pneumoniae
. The MIC at which 90% of the isolates were inhibited and the minimal bactericidal concentration at which 90% of the isolates were killed by NVP-PDF386 for all isolates of
C. pneumoniae
were 0.008 μg/ml (range, 0.008 to 0.015 μg/ml) compared to 0.25 and 0.06 μg/ml for levofloxacin and clarithromycin, respectively.
Trypanocidal and Leishmanicidal Properties of Substitution-Containing Chalcones
Authors: Lunardi Fabiane , Guzela Michel , Rodrigues Andrea T. , Corrêa Rogério , Eger-Mangrich Iriane , Steindel Mário , Grisard Edmundo C. , Assreuy Jamil , Calixto João B. , Santos Adair R. S. 
Published: March 2003

ABSTRACTTen chalcones were synthesized and tested as potential leishmanicidal and trypanocidal agents. All tested compounds caused concentration-dependent inhibition of the in vitro growth ofLeishmania braziliensisandTrypanosoma cruziwith no significant toxic effect towards host macrophages. Our results show that the positions of the substituents seem to be critical for their antiprotozoal activities.
Efficacy of Micafungin Alone or in Combination against Systemic Murine Aspergillosis
Authors: Luque Javier Capilla , Clemons Karl V. , Stevens David A. 
Published: March 2003

ABSTRACT

We tested the efficacy of micafungin (FK) alone or in combination with other antifungals against systemic murine aspergillosis. FK alone at 10 mg/kg of body weight/dose prolonged survival (
P
= 0.01) and reduced CFU in the brain and kidney. Combination therapy that used suboptimal FK with amphotericin B or itraconazole prolonged survival. Although no survivors were free of infection, no antagonism was seen. Nikkomycin Z with FK showed significantly greater potency (
P
< 0.01) than either alone.
PCR-Oligonucleotide Ligation Assay for Detection of Point Mutations Associated with Quinolone Resistance in
Streptococcus pneumoniae
Authors: Bui Mai-Ha , Stone Gregory G. , Nilius Angela M. , Almer Laurel , Flamm Robert K. 
Published: March 2003

ABSTRACT

We have developed a PCR-oligonucleotide ligation assay to rapidly identify base substitutions in topoisomerase genes that are associated with quinolone resistance in clinical isolates of
Streptococcus pneumoniae
. Thirty-seven strains for which the ciprofloxacin MICs were ≥4 μg/ml and 16 strains for which the MICs were ≤2 μg/ml were assayed. Compared with sequence data, the assay correctly identified the DNA bases that encoded amino acids at the four positions most commonly associated with quinolone resistance (Ser79 and Asp83 of ParC and Ser81 and Glu85 of GyrA). Therefore, this procedure can rapidly distinguish single base substitutions associated with quinolone-resistant topoisomerases in
S. pneumoniae
.
mecA
-
blaZ
Corepressors in Clinical
Staphylococcus aureus
Isolates
Authors: Rosato Adriana E. , Kreiswirth Barry N. , Craig William A. , Eisner William , Climo Michael W. , Archer Gordon L. 
Published: March 2003

ABSTRACT

The presence and nucleotide sequences of the two
mecA
repressors,
mecI
and
blaI
, were assessed in 73 clinical
Staphylococcus aureus
isolates. Isolates with
mecI
mutations were grouped into unique clonal types based on their
spa
nucleotide repeat patterns. Forty-three of the 45 (96%) isolates with mutant
mecI
or with a deletion of
mecI
contained
blaI
, while
blaI
was present in only 21 of 28 (78%) isolates with wild-type
mecI
(
P
< 0.05). Among 22 additional isolates that did not contain
blaI
, all had wild-type
mecI
sequences. We conclude that oxacillin-resistant
S. aureus
must have at least one of the two functional
mecA
regulators.
Frequency of Mutation to Rifampin Resistance in
Streptococcus pneumoniae
Clinical Strains:
hexA
and
hexB
Polymorphisms Do Not Account for Hypermutation
Authors: Morosini María-Isabel , Baquero María-Rosario , Sánchez-Romero J. M. , Negri María-Cristina , Galán Juan-Carlos , del Campo Rosa , Pérez-Díaz J. C. , Baquero Fernando 
Published: March 2003

ABSTRACT

The frequency of mutation to rifampin resistance of 200 clinical
Streptococcus pneumoniae
isolates was examined. Two peaks were observed in the distribution, with mode frequencies of 2.5 × 10
−7
(20% of isolates) and 2.5 × 10
−8
. The
hexA
and
hexB
gene entire sequences were analyzed in 13 isolates. Sequences from both hypermutable and “normomutable” strains were conserved relative to that of the R6
S. pneumoniae
control strain. The phenotypic Hex system proficiency, in terms of transforming efficiency, was also maintained irrespective of the variations in mutation frequency values.
Interactions of 1263W94 with Other Antiviral Agents in Inhibition of Human Cytomegalovirus Replication
Authors: Selleseth Dean W. , Talarico Christine L. , Miller Teresa , Lutz Michael W. , Biron Karen K. , Harvey Robert J. 
Published: March 2003

ABSTRACT
Inhibition of human cytomegalovirus (HCMV) by 1263W94 was additive dosewise in combination with ganciclovir, acyclovir, and foscarnet. None of the commonly used anti-human immunodeficiency virus agents antagonized the inhibition of HCMV by 1263W94. The data were analyzed by a modified isobologram procedure that measures the strength and statistical significance of drug interactions.
Significance of Genomic DNA Group Delineation in Comparative Studies of Antimicrobial Susceptibility of
Acinetobacter
spp
Authors: Houang Elizabeth T. S. , Chu Yiu Wai , Chu K. Y. , Ng K. C. , Leung C. M. , Cheng A. F. B. 
Published: March 2003

ABSTRACT

There were significant differences in antimicrobial susceptibilities in isolates of genomic DNA groups 2 (
Acinetobacter baumannii
), 3, and 13TU collected from the same sources, e.g., patients in intensive care units and general wards, and in isolates of the same group collected from different sources. The delineation of genomic groups is important in comparative surveillance studies of antimicrobial susceptibilities.
Pathogenic
Nocardia
,
Rhodococcus
, and Related Organisms Are Highly Susceptible to Imidazole Antifungals
Authors: Dabbs Eric R. , Naidoo Samantha , Lephoto Catherine , Nikitina Natalya 
Published: March 2003

ABSTRACT

Rhodococcus equi
and species of
Nocardia
and
Gordonia
may be human opportunistic pathogens. We find that these, as well as several isolates from closely related genera, are highly susceptible to the imidazoles bifonazole, clotrimazole, econazole, and miconazole, whose MICs are ≤1 μg/ml. In liquid cultures 1 μg of the drug/ml was bacteriostatic and 10 μg/ml was bactericidal. On solid media at 10 μg of azole/ml no resistant mutants could be isolated. An MIC of 1 to 15 μg/ml was observed with ketoconazole, whereas none of these organisms was inhibited by the triazoles fluconazole and voriconazole (100 μg/ml). Imidazoles may offer the prospect of treatment of nocardioform mycetomas and may provide the basis for the development of additional antimicrobial agents to combat these pathogens.
Flagella Are Virulence Determinants of
Burkholderia pseudomallei
Authors: Chua K. L. , Chan Y. Y. , Gan Y. H. 
Published: March 2003

ABSTRACT

Burkholderia pseudomallei
, a facultatively intracellular pathogen, is a flagellated and motile gram-negative bacterium and is the causative agent of melioidosis in humans. Flagella are commonly recognized as important virulence determinants expressed by bacterial pathogens since the motility phenotype imparted by these organelles often correlates with the ability of an organism to cause disease. We used a virulent isolate of
B. pseudomallei
, KHW, to construct an isogenic deletion mutant with a mutation in the flagellin gene (
fliC
) by gene replacement transposon mutagenesis. The KHWΔ
fliC
Km mutant was aflagellate and nonmotile in semisolid agar. The isogenic KHWΔ
fliC
Km mutant was not impaired in terms of the ability to invade and replicate in cultured human lung cells compared with the wild type. It was also equally virulent in slow-killing assays involving
Caenorhabditis elegans
, but it was avirulent during intranasal infection of BALB/c mice. Very few bacteria, if any, were isolated from the lungs and spleens of KHWΔ
fliC
Km
-
infected mice. In contrast, the bacterial loads in the lungs and spleens were similar in mice infected with KHW and in mice infected with the complemented mutant, KHWΔ
fliC
Km/pUCP28T
fliC.
Unlike the Syrian hamster or diabetic rat models of infection, the
B. pseudomallei
flagellin was also a virulence factor during intraperitoneal infection of BALB/c mice. In this study, all animals infected with KHWΔ
fliC
Km remained healthy and did not succumb to disease regardless of the route of infection. The flagellum is therefore an important and necessary virulence determinant of
B. pseudomallei
during intranasal and intraperitoneal infection of mice.
Interleukin-18 Impairs the Pulmonary Host Response toPseudomonas aeruginosa
Authors: Schultz Marc J. , Knapp Sylvia , Florquin Sandrine , Pater Jennie , Takeda Kiyoshi , Akira Shizuo , van der Poll Tom 
Published: March 2003

ABSTRACTInterleukin-18 (IL-18) is a potent cytokine with many different proinflammatory activities. To study the role of IL-18 in the pathogenesis ofPseudomonaspneumonia, IL-18-deficient (IL-18−/−) and wild-type mice were intranasally inoculated withPseudomonasaeruginosa. IL-18 deficiency was associated with reduced outgrowth ofPseudomonasin the lungs and diminished dissemination of the infection. In addition, pulmonary inflammation (histopathology) and levels of tumor necrosis factor alpha, IL-6, and macrophage inflammatory protein-2 in lungs and plasma were lower inIL-18−/−mice. Consistent with results obtained forIL-18−/−mice, treatment of wild-type mice with a neutralizing IL-18 binding protein-immunoglobulin G Fc fusion construct also attenuated outgrowth ofPseudomonascompared with that for mice treated with a control protein. These results demonstrate that the presence of endogenous IL-18 activity facilitates inflammatory responses in the lung duringPseudomonaspneumonia, concurrently impairing bacterial clearance.
Prevalence and Distribution of Adhesins in Invasive Non-Type b Encapsulated
Haemophilus influenzae
Authors: Rodriguez Carina A. , Avadhanula Vasanthi , Buscher Amy , Smith Arnold L. , St. Geme Joseph W. , Adderson Elisabeth E. 
Published: March 2003

ABSTRACT

Adhesion to the respiratory epithelium plays an important role in
Haemophilus influenzae
infection. The distribution of
H. influenzae
adhesins in type b and nontypeable strains has been characterized, but little is known about the prevalence of these factors in non-type b encapsulated strains. We analyzed 53 invasive type a, type e, and type f strains for the presence of
hap
,
hia
,
hmw
, and
hif
genes; Hap, Hia, and HMW1/2 adhesins; and hemagglutinating pili. The
hap
gene was ubiquitous, and homologs of
hmw
and
hia
were present in 7 of 53 (13.2%) and 45 of 53 (84.9%) strains, respectively. Hap was detected in 28 of 45 (62.2%)

hap
+

strains, HMW1/2 was detected in 5 of 7 (71.4%)

hmw
+

strains, and Hia was detected in 31 of 45 (68.8%)

hia
+

strains. The
hif
gene cluster was present in 26 of 53 strains (49.1%), and 21 of 26

hif
+

strains (80.8%) agglutinated (HA) red blood cells. Nine isolates exhibited HA but lacked the
hif
gene cluster. The distribution of adhesin genes correlated with the genetic relatedness of the strains. Strains belonging to one type a clonotype and the major type e clonotype possessed
hia
but lacked the
hif
cluster. Strains belonging to the second type a clonotype possessed both
hia
and
hif
genes. All type f strains belonging to the major type f clonotype possessed
hia
and lacked
hifB
. Although the specific complement of adhesin genes in non-type b encapsulated
H. influenzae
varies, most invasive strains express Hap and Hia, suggesting these adhesins may be especially important to the virulence of these organisms.
Effect of Interleukin-8 and Granulocyte Colony-Stimulating Factor on Priming and Activation of Bovine Neutrophils
Authors: Mitchell Gordon B. , Albright Betty N. , Caswell Jeff L. 
Published: March 2003

ABSTRACTNeutrophils are important effector cells in innate and acquired immunity, but the magnitude and character of their phagocytic and bactericidal responses depend on cues derived from mediators in the local microenvironment. This study investigated the effect of bovine interleukin-8 (IL-8) and granulocyte colony-stimulating factor (G-CSF) on priming and activation of bovine neutrophils in vitro and in vivo. Neutrophils were isolated from blood and cultured for up to 18 h, with or without cytokines, and thenMannheimia haemolytica-induced oxidative burst and phagocytosis ofStaphylococcus aureuswere measured by flow cytometry. Neither IL-8 nor G-CSF directly triggered an oxidative burst, but incubation with these cytokines for 18 h primed neutrophils for a greater oxidative burst triggered byM. haemolyticaand for enhanced uptake ofS. aureus. The maximal response was observed when neutrophils were incubated with both cytokines together, at concentrations of 200 ng/ml for G-CSF and 400 ng/ml for IL-8. The IL-8-induced priming effect was reduced by treatment with a neutralizing antibody to IL-8, and was not attributed to endotoxin contamination. Instillation of IL-8 into the lung using a bronchoscope induced neutrophil recruitment within 18 h. Neutrophils from IL-8-treated lung showed dose-dependent enhancement of the oxidative burst triggered byM. haemolytica. Histologically, neutrophils filled alveoli and bronchioles, and scattered macrophages contained neutrophils with morphological features of apoptosis. Thus, prolonged in vitro or in vivo exposure to IL-8 and/or G-CSF enhances the subsequent oxidative burst and phagocytic responses of bovine neutrophils.
Cross-Reactivity of Antibodies against PorA after Vaccination with a Meningococcal B Outer Membrane Vesicle Vaccine
Authors: Vermont C. L. , van Dijken H. H. , Kuipers A. J. , van Limpt C. J. P. , Keijzers W. C. M. , van der Ende A. , de Groot R. , van Alphen L. , van den Dobbelsteen G. P. J. M. 
Published: March 2003

ABSTRACT
The cross-reactivity of PorA-specific antibodies induced by a monovalent P1.7-2,4 (MonoMen) and/or a hexavalent (HexaMen) meningococcal B outer membrane vesicle vaccine (OMV) in toddlers and school children was studied by serum bactericidal assays (SBA). First, isogenic vaccine strains and PorA-identical patient isolates were compared as a target in SBA, to ensure that the vaccine strains are representative for patient isolates. Geometric mean titers (GMTs) in SBA against patient isolates with subtypes P1.5-2,10 and P1.5-1,2-2 after vaccination with HexaMen were generally lower than those against vaccine strains with the same subtype, although the percentage of vaccine responders (≥4-fold increase in SBA after vaccination) was not affected. Using various P1.7-2,4 patient isolates, GMTs as well as the number of vaccine responders were higher than for the P1.7-2,4 vaccine strain, indicating that the use of the P1.7-2,4 vaccine strain may have underestimated the immunogenicity of this subtype in HexaMen. Secondly, the cross-reactivity of antibodies induced by MonoMen and HexaMen was studied using several patient isolates that differed from the vaccine subtypes by having minor antigenic variants of one variable region (VR), by having a completely different VR or by having a different combination of VRs. MonoMen induced P1.4-specific antibodies that were cross-reactive with P1.4 variants P1.4-1 and P1.4-3. HexaMen induced a broader cross-reactive antibody response against various patient isolates with one VR identical to a vaccine subtype or a combination of VRs included in HexaMen. Cross-reactivity, measured by a fourfold increase in SBA after vaccination, against these strains ranged from 23 to 92% depending on the subtype of the tested strain and was directed against both VR1 and VR2. The extended cross-reactivity of vaccinee sera induced by HexaMen against antigenic variants has important favorable implications for meningococcal B OMV vaccine coverage.
Virulence, Immunogenicity, and Protective Efficacy of Two RecombinantMycobacterium bovisBacillus Calmette-Guérin Strains Expressing the Antigen ESAT-6 fromMycobacterium tuberculosis
Authors: Bao Lang , Chen Wei , Zhang Huidong , Wang Xiaoying 
Published: March 2003

ABSTRACTWe constructed two recombinantMycobacterium bovisBCG (rBCG) strains expressing ESAT-6 ofMycobacterium tuberculosis, named rBCG-1 and rBCG-2. rBCG-1 contained the ESAT-6 gene linked to BCGhsp60and expressed a fusion protein, while rBCG-2, with a secretory sequence, could secret ESAT-6 into the culture medium. There was no evidence for increased virulence of the two rBCG strains when we made a comparison between them and BCG with regard to organ bacterial loads, lung histology, and survival time. rBCG-1 induced significantly higher specific antibody titers and stronger cellular immune response than BCG, whereas rBCG-2 had immunogenicity similar to that of the parental BCG strain. Both rBCG-1 and rBCG-2 conferred marked protection againstM. tuberculosisinfection, yet in terms of protective efficacy, they showed no significant improvements upon conventional BCG vaccine.
Surfactant Protein D-Mediated Aggregation ofPneumocystis cariniiImpairs Phagocytosis by Alveolar Macrophages
Authors: Yong Suk-Joong , Vuk-Pavlovic Zvezdana , Standing Joseph E. , Crouch Erika C. , Limper Andrew H. 
Published: March 2003

ABSTRACTPneumocystis cariniiremains an important and potentially fatal cause of opportunistic pneumonia. Animal studies reveal that substantial quantities of surfactant protein D (SP-D) accumulate in the airspaces duringP. cariniipneumonia and are particularly abundant in aggregates of organisms. Due to the multimeric structure of SP-D, we hypothesized that SP-D mediates aggregation of the organism. From previous clinical studies it is known that aggregated organisms are conspicuous in sections of lung tissue and bronchoalveolar lavage (BAL) fluids of humans with activeP. cariniipneumonia. Herein, we observe that SP-D levels increased at least fourfold in BAL fluids of patients withP. cariniipneumonia. Next, a spectrophotometric sedimentation assay was developed to assess the aggregation ofP. cariniiin vitro by SP-D.P. cariniiorganisms were first stripped with glutathione to remove bound SP-D and subsequently incubated in the presence of SP-D and 2 mM calcium.P. cariniiincubated with natural SP-D (10 μg/ml) containing dodecamers and higher-order forms exhibited aggregation and enhanced sedimentation compared to that of glutathione-strippedP. carinii. Aggregation was also enhanced by the concentrated supernatant of rat BAL fluid, and this effect was abolished by the selective removal of SP-D from the lavage fluid.P. cariniiaggregation was reduced by maltose, mannose, and EDTA, consistent with the role of the SP-D C-type lectin domain (CRD) in the aggregation event. Comparisons of different molecular forms of SP-D showed that dodecamers—but not trimeric subunits—mediate optimal aggregation ofP. carinii. Aggregation ofP. cariniiby SP-D was shown to be responsible for the impaired phagocytosis of the organisms by alveolar macrophages. Thus, SP-D-mediated aggregation ofP. cariniimay represent one means by which the organism avoids elimination by the host.
A New Vaccine against Tuberculosis Affords Greater Survival after Challenge than the Current Vaccine in the Guinea Pig Model of Pulmonary Tuberculosis
Authors: Horwitz Marcus A. , Harth Günter 
Published: March 2003

ABSTRACTTuberculosis (TB) remains an enormous global health problem, and a new vaccine against TB more potent than the current inadequate vaccine,MycobacteriumbovisBCG, is urgently needed. We describe a recombinant BCG vaccine (rBCG30) expressing and secreting the 30-kDa major secretory protein ofMycobacterium tuberculosis, the primary causative agent of TB, that affords greater survival after challenge than parental BCG in the highly demanding guinea pig model of pulmonary TB. Animals immunized with rBCG30 and then challenged by aerosol with a highly virulent strain ofM. tuberculosissurvived significantly longer than animals immunized with conventional BCG. The parental and recombinant vaccine strains are comparably avirulent in guinea pigs, as they display a similar pattern of growth and clearance in the lung, spleen, and regional lymph nodes. The pMTB30 plasmid encoding the 30-kDa protein is neither self-transmissible nor mobilizable to other bacteria, including mycobacteria. The pMTB30 plasmid can be stably maintained inEscherichia colibut is expressed only in mycobacteria. The recombinant and parental strains are sensitive to the same antimycobacterial antibiotics. rBCG30, the first vaccine against TB more potent than nearly century-old BCG, is being readied for human clinical trials.
Cloning and Expression of theEscherichia coliK1 Outer Membrane Protein A Receptor, a gp96 Homologue
Authors: Prasadarao Nemani V. , Srivastava Pramod K. , Rudrabhatla Rajyalakshmi S. , Kim Kwang Sik , Huang Sheng-he , Sukumaran Sunil K. 
Published: March 2003

ABSTRACTEscherichia coliis one of the most common gram-negative bacteria that cause meningitis in neonates. Our previous studies have shown that outer membrane protein A (OmpA) ofE. coliinteracts with a 95-kDa human brain microvascular endothelial cell (HBMEC) glycoprotein, Ecgp, for invasion. Here, we report the identification of a gene that encodes Ecgp by screening of an HBMEC cDNA expression library as well as by 5′ rapid amplification of cDNA ends. The sequence of the Ecgp gene shows that it is highly similar to gp96, a tumor rejection antigen-1, and contains an endoplasmic reticulum retention signal, KDEL. Overexpression of either Ecgp or gp96 in both HBMECs and CHO cells increasesE. colibinding and invasion. We further show that Ecgp gene-transfected HBMECs express Ecgp on the cell surface despite the presence of the KDEL motif. Northern blot analysis of total RNA from various eukaryotic cells indicates that Ecgp is significantly expressed in HBMECs. Recombinant His-tagged Ecgp blockedE. coliinvasion efficiently by binding directly to the bacteria. These results suggest that OmpA ofE. coliK1 interacts with a gp96-like molecule on HBMECs for invasion.