bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pharmacodynamics of the Antibacterial Effect of and Emergence of Resistance to Doripenem in Pseudomonas aeruginosa and Acinetobacter baumannii in an
In Vitro
Pharmacokinetic Model
Authors: Bowker Karen E. , Noel Alan R. , Tomaselli Sharon G. , Elliott Heather , MacGowan Alasdair P. 
Published: June 2012

ABSTRACT

An
in vitro
dilutional pharmacokinetic model of infection was used to study the pharmacodynamics of doripenem in terms of the ability to kill
Pseudomonas aeruginosa
or
Acinetobacter baumannii
and also changes in their population profiles. In dose-ranging studies, the cumulative percentages of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (
T
MIC
s) required for doripenem to produce a 24-h bacteriostatic effect and a −2-log-unit reduction in viable count were 25% ± 11% and 35% ± 13%, respectively, for
P. aeruginosa
(MIC range, 0.24 to 3 mg/liter) and 20% ± 11% and 33% ± 12%, respectively, for
Acinetobacter
spp. (MIC range, 0.45 to 3.0 mg/liter). A
T
MIC
of >40 to 50% produced a maximum response with both species at 24 h or 48 h of exposure. After 24 h of exposure to doripenem at a
T
MIC
in the range of 12.5 to 37.5%,
P. aeruginosa
and
A. baumannii
population profiles revealed mutants able to grow on 4× MIC-containing medium; such changes were further amplified by 48 h of exposure. Dose-fractionation experiments targeting
T
MIC
s of 12.5%, 25%, or 37.5% as six exposures, two exposures, or a single exposure over 48 h with a single strain of
P. aeruginosa
indicated that changes in population profiles were greatest with multiple exposures at
T
MIC
targets of 12.5 or 25%. In contrast, multiple exposures at 37.5%
T
MIC
most effectively suppressed total bacterial counts and changes in population profiles. Simulations of human doses of doripenem of 500 mg, 1,000 mg, 2,000 mg, and 3,000 mg every 8 h over 96 h showed marked initial killing up to 6 h but growback thereafter. Changes in population profiles occurred only in the regimen of 500 mg every 8 h against
P. aeruginosa
but occurred with all dose regimens for
A. baumannii
strains. A doripenem
T
MIC
of ≥40 to 50% is maximally effective in killing
P. aeruginosa
or
A. baumannii
and suppressing changes in population profiles in short-term experiments for up to 48 h; however, a
T
MIC
of 12.5 to 25% amplifies population changes, especially with exposures every 8 h. In longer-term experiments, up to 96 h, even doripenem doses of 4 to 6 times those used in human studies proved incapable of pathogen eradication and prevention of changes in population profiles. The association of a
T
MIC
of 25 to 37.5% with changes in population profiles has implications in terms of future clinical breakpoint setting.
Anti-Protective Antigen IgG Enzyme-Linked Immunosorbent Assay for Diagnosis of Cutaneous Anthrax in India
Authors: Ghosh N. , Goel A. K. 
Published: June 2012

ABSTRACTAnthrax caused byBacillus anthracisis a public health problem in several developing countries whose main source of income is farming. Anthrax is a disease of herbivorous animals, and humans can be infected by handling infected animals or contaminated animal products. Specific diagnostic tests are unavailable in India for the detection and confirmation of cutaneous anthrax in humans. Here, we describe the development of an enzyme-linked immunosorbent assay (ELISA) for detection of serum antibodies againstBacillus anthracisprotective antigen in the Indian population. A total of 405 serum samples collected from different groups were tested by the developed ELISA. The assay provided a specificity of 99.41% (95% confidence interval [CI], 97.89 to 99.93) and a sensitivity of 100% (CI, 94.4 to 100) using a cutoff value of 0.29 ELISA unit (EU). The positive predictive value (PPV) and negative predictive value (NPV) of the assay were 97% and 100%, respectively. The efficiency and J index for the reliability of the assay were 99.5% and 0.994, respectively. The assay can be a very useful tool for surveillance as well as for diagnosis of cutaneous anthrax cases in India.
Risk Factors Associated with Indeterminate Gamma Interferon Responses in the Assessment of Latent Tuberculosis Infection in a High-Incidence Environment
Authors: Oni Tolu , Gideon Hannah P. , Bangani Nonzwakazi , Tsekela Relebohile , Seldon Ronnett , Wood Kathryn , Wilkinson Katalin A. , Goliath Rene T. , Ottenhoff Tom H. M. , Wilkinson Robert J. 
Published: June 2012

ABSTRACT

The performance of gamma interferon (IFN-γ) release assays (IGRA) in the detection of latent tuberculosis (TB) infection is limited by the higher rates of indeterminate results in HIV-infected persons, who bear the brunt of TB disease in some high-burden settings. The objective of the study was to evaluate predictors of indeterminate IGRA results in the overall study population and in HIV-infected persons. The study setting is Khayelitsha, an informal township in the Western Cape of South Africa, with a high burden of TB and HIV infection. A total of 561 asymptomatic persons were recruited from the day hospital and youth centers. A questionnaire was used to collect demographic information, and blood tests, including CD4 counting and a 7-day in-house IGRA, were performed. The overall prevalence of indeterminate IGRA results was 8.6% (48/561), and this was higher in HIV-infected than in HIV-uninfected persons (11.5% [38/330] versus 4.3% [10/231], respectively;
P
= 0.003). In the overall study population, predictors of indeterminate IGRA results were the presence of HIV infection (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.10 to 5.08) and the presence of a
Mycobacterium bovis
BCG scar (OR, 2.48; 95% CI, 1.23 to 5.01). Long-term township residents were significantly less likely to have indeterminate results than recent migrants (OR, 0.30; 95% CI, 0.11 to 0.80). Among HIV-infected persons, participants with CD4 counts of >200 cells/mm
3
and long-term residents were significantly less likely to have indeterminate IGRA results (OR of 0.21 with a 95% CI of 0.09 to 0.48 and OR of 0.22 with a 95% CI of 0.07 to 0.68, respectively). We evaluated risk factors for indeterminate IGRA results and report a higher rate of indeterminate results among HIV-infected persons, particularly those with lower CD4 counts. Of note, a recent move to the township was associated with a higher risk of indeterminate IGRA results.
Evaluation of Three Commercial Varicella-Zoster Virus IgG Enzyme-Linked Immunosorbent Assays in Comparison to the Fluorescent-Antibody-to-Membrane-Antigen Test
Authors: Sauerbrei Andreas , Schäfler Anna , Hofmann Jörg , Schacke Michael , Gruhn Bernd , Wutzler Peter 
Published: June 2012

ABSTRACT
Commercial serologic assays for varicella-zoster virus (VZV), which enable reliable determination of VZV immune status and are amenable to automation, are needed. The present study compares the automated performance of the VZV whole-cell enzyme-linked immunosorbent assay (ELISA) Enzygnost anti-VZV/IgG, the Euroimmun anti-VZV ELISA (IgG) based on highly purified viral proteins, and the VZV glycoprotein (gp)-based Serion ELISA Classic VZV IgG. The fluorescent-antibody-to-membrane-antibody (FAMA) test was used as a reference. A total of 638 serum samples from VZV-negative children, blood donors, varicella vaccinees, and bone marrow transplant recipients were included. The Enzygnost anti-VZV/IgG and the Serion ELISA Classic VZV IgG showed sensitivities of 99.6% and 99.2%, respectively, and the Euroimmun anti-VZV ELISA (IgG) had a significantly lower sensitivity of 90.5%. Specificity was calculated as 100% for both the Euroimmun anti-VZV ELISA (IgG) and for the Enzygnost anti-VZV/IgG, and the Serion ELISA Classic VZV IgG had a significantly lower specificity of 89.4%. Quantitative results of all ELISAs correlated well, but there was a poor quantitative correlation between the ELISAs and FAMA. In conclusion, this study does not show any superiority of a gp- and a protein-based ELISA compared to a whole-cell ELISA for the automated detection of VZV-specific IgG. The automated performance of the Enzygnost anti-VZV/IgG assay correlated best with the FAMA reference assay.
A High Percentage of Serum Samples That Test Reactive by Enzyme Immunoassay for Anti-Brucella Antibodies Are Not Confirmed by the Standard Tube Agglutination Test
Authors: Binnicker Matthew J. , Theel Elitza S. , Larsen Staci M. , Patel Robin 
Published: June 2012

ABSTRACTWe describe a retrospective analysis ofBrucellaenzyme immunoassay (EIA) IgM and IgG results compared to those of the standard tube agglutination test (SAT). Among 1,091 samples tested, 104 (9.5%) and 24 (2.2%) sera were positive by IgM and IgG EIA, respectively. Supplemental testing by SAT showed that 82.7% (86/104) of IgM EIA-reactive samples and 54.2% (13/24) of IgG EIA-reactive samples were negative by SAT. Testing all EIA screen-reactive samples by SAT is required when evaluating patients for potential brucellosis. Due to the limitations of serology, culture remains the gold standard for detectingBrucellainfection.
Duration of Immunity against Mycobacterium bovis following Neonatal Vaccination with Bacillus Calmette-Guérin Danish: Significant Protection against Infection at 12, but Not 24, Months
Authors: Thom M. L. , McAulay M. , Vordermeier H. M. , Clifford D. , Hewinson R. G. , Villarreal-Ramos B. , Hope J. C. 
Published: June 2012

ABSTRACTVaccination of neonatal calves withMycobacterium bovisbacillus Calmette-Guérin (BCG) induces a significant degree of protection against bovine tuberculosis, caused by infection with virulentM. bovis. In two independent experiments, we assessed the duration of the protective immunity induced in calves by neonatal vaccination with BCG Danish. Protection from disease was assessed at 12 and 24 months postvaccination in cattle challenged via the endotracheal route withM. bovis. We also assessed antigen-specific immune responses to assess their utility as correlates of protection. At 12 months postvaccination, significant reductions in lung and lymph node pathologies were observed compared to nonvaccinatedM. bovis-challenged control cattle. At 24 months post-BCG vaccination, there was a reduction in lung and lymph node pathology scores and in bacterial burden. However, when comparing vaccinated and control groups, this did not reach statistical significance. Vaccination induced long-lived antigen (purified protein derivative [PPD])-specific gamma interferon (IFN-γ) release in whole-blood cultures, which remained above baseline levels for more than 20 months (approximately 90 weeks). The number of antigen-specific IFN-γ-secreting central memory T cells present at the time ofM. bovischallenge was significantly higher in vaccinated than in control animals at 12 months postvaccination, but not at 24 months. Vaccination of neonatal calves with BCG Danish induced protective immune responses against bovine TB which were maintained for at least 12 months postvaccination. These studies provide data on the immunity induced by BCG vaccination in calves; the results could inform vaccination strategies for the control of bovine TB in United Kingdom cattle herds.
Differentiation of Streptococcus pneumoniae from Nonpneumococcal Streptococci of the Streptococcus mitis Group by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry
Authors: Werno Anja M. , Christner Martin , Anderson Trevor P. , Murdoch David R. 
Published: June 2012

ABSTRACT

The differentiation of species within the
Streptococcus mitis
group has posed a problem in the routine diagnostic microbiology laboratory for some time. It also constitutes a major weakness of recently introduced matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) fingerprinting systems. As the phylogenetic resolution of the spectral similarity measures employed by these systems is insufficient to reliably distinguish between the most closely related members of the group, the major pathogen
Streptococcus pneumoniae
is frequently misidentified. In this study, a comparative analysis of MALDI-TOF spectra of several species from the
S. mitis
group has been performed in order to identify single peaks that could be used to improve mass spectrometry-based identification of the respective species. A characteristic peak profile could be identified that unambiguously distinguished the 14
S. pneumoniae
isolates studied from 33 nonpneumococcal isolates of the
S. mitis
group. In addition, specific peak combinations could be assigned to other members of the group. The findings of this study suggest that it is possible to distinguish different species of the
S. mitis
group by close analysis of their mass peak profiles.
Molecular Characterization Reveals Three Distinct Clonal Groups among Clinical Shiga Toxin-Producing Escherichia coli Strains of Serogroup O103
Authors: Iguchi Atsushi , Iyoda Sunao , Ohnishi Makoto 
Published: June 2012

ABSTRACTShiga toxin-producingEscherichia coli(STEC) is one of the most important groups of food-borne pathogens, and STEC strains belonging to the serotype O103:H2 can cause diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome in humans. STEC O103:non-H2 strains are also sometimes isolated from human patients, but their genetic characteristics and role in significant human enteric disease are not yet understood. Here, we investigated 17 STEC O103:non-H2 strains, including O103:H11, O103:H25, O103:HUT (UT [untypeable]), and O103:H− (nonmotile) isolated in Japan, and their characteristics were compared to those of STEC O103:H2 and other serotype STEC strains. Sequence analyses offliCandeaegenes revealed that strains possessed any of the following combinations:fliC-H2/eae-epsilon,fliC-H11/eae-beta1, andfliC-H25/eae-theta, wherefliC-H2, -H11, and -H25 indicatefliCgenes encoding H2, H11, and H25 flagella antigens, respectively, andeae-epsilon, -beta1, and -theta indicateeaegenes encoding epsilon, beta1, and theta subclass intimins, respectively. Phylogenetic analysis based on the sequences of seven housekeeping genes demonstrated that the O103:H11/[fliC-H11] and O103:H25/[fliC-H25] strains formed two distinct groups, different from that of the O103:H2/[fliC-H2] strains. Interestingly, a group consisting of O103:H11 strains was closely related to STEC O26:H11, which is recognized as a most important non-O157 serotype, suggesting that the STEC O103:H11 and STEC O26:H11 clones evolved from a common ancestor. The multiplex PCR system for the rapid typing of STEC O103 strains described in the present study may aid clinical and epidemiological studies of the STEC O103:H2, O103:H11, and O103:H25 groups. In addition, our data provide further insights into the high variability of STEC stains with emerging new serotypes.
Phylogenetic Analysis of the Spirochete Borrelia microti, a Potential Agent of Relapsing Fever in Iran
Authors: Naddaf Saied Reza , Ghazinezhad Behnaz , Bahramali Golnaz , Cutler Sally Jane 
Published: June 2012

ABSTRACT

We report a role for
Borrelia microti
as a cause of relapsing fever in Iran supported by robust epidemiological evidence. The molecular identity of this spirochete and its relation with other relapsing fever borreliae have, until now, been poorly delineated. We analyzed an isolate of
B. microti
, obtained from
Ornithodoros erraticus
ticks, by sequencing four loci (16S rRNA,
flaB
,
glpQ
, intragenic spacer [IGS]) and comparing these sequences with those of other relapsing fever borreliae. Phylogenetic analysis using concatenated sequences of 16S rRNA,
flaB
, and
glpQ
grouped
B. microti
alongside three members of the African group,
B. duttonii
,
B. recurrentis
, and
B. crocidurae
, which are distinct from
B. persica
, the most prevalent established cause of tick-borne relapsing fever in Iran. The similarity values for 10 concatenated sequences totaling 2,437 nucleotides ranged from 92.11% to 99.84%, with the highest homologies being between
B. duttonii
and
B. microti
and between
B. duttonii
and
B. recurrentis
. Furthermore, the more discriminatory IGS sequence analysis corroborated the close similarity (97.76% to 99.56%) between
B. microti
and
B. duttonii
. These findings raise the possibility that both species may indeed be the same and further dispel the one-species, one-vector theory that has been the basis for classification of relapsing fever
Borrelia
for the last 100 years.
High Hepatitis E Virus Seroprevalence in Forestry Workers and in Wild Boars in France
Authors: Carpentier Audrey , Chaussade Hélène , Rigaud Emma , Rodriguez Josefa , Berthault Camille , Boué Franck , Tognon Mauro , Touzé Antoine , Garcia-Bonnet Nathalie , Choutet Patrick , Coursaget Pierre 
Published: June 2012

ABSTRACT
Hepatitis E virus (HEV) is a fecally and orally transmitted human pathogen of worldwide distribution. In industrial countries, HEV is observed in an increasing number of autochthonous cases and is considered to be an emerging pathogen. A growing body of evidence suggests that HEV is a zoonotic disease, and pig handlers and pig veterinarians have been reported to be high-risk groups for HEV infection. The aims of the present study were to establish the prevalence of anti-HEV in wild boars in France and to identify whether forestry workers are at a higher risk of HEV infection. Three different anti-HEV tests were used to compare their effectiveness in detecting anti-HEV in the general population. The most sensitive test was then used to investigate HEV seroprevalence in 593 forestry workers and 421 wild boars. Anti-HEV was detected in 31% of the forestry workers and 14% of the wild boars. Detection of anti-HEV in humans was correlated with age, geographical location, and occupational activity and in wild boars was correlated with geographical location. HEV infection is frequent in woodcutters in France, and it varies geographically. Further studies are needed to confirm these findings and to elucidate the transmission route and the exact virus reservoirs.
Field Monitoring of Avian Influenza Viruses: Whole-Genome Sequencing and Tracking of Neuraminidase Evolution Using 454 Pyrosequencing
Authors: Croville Guillaume , Soubies Sébastien Mathieu , Barbieri Johanna , Klopp Christophe , Mariette Jérôme , Bouchez Olivier , Camus-Bouclainville Christelle , Guérin Jean-Luc 
Published: June 2012

ABSTRACT

Adaptation of avian influenza viruses (AIVs) from waterfowl to domestic poultry with a deletion in the neuraminidase (NA) stalk has already been reported. The way the virus undergoes this evolution, however, is thus far unclear. We address this question using pyrosequencing of duck and turkey low-pathogenicity AIVs. Ducks and turkeys were sampled at the very beginning of an H6N1 outbreak, and turkeys were swabbed again 8 days later. NA stalk deletions were evidenced in turkeys by Sanger sequencing. To further investigate viral evolution, 454 pyrosequencing was performed: for each set of samples, up to 41,500 reads of ca. 400 bp were generated and aligned. Genetic polymorphisms between duck and turkey viruses were tracked on the whole genome. NA deletion was detected in less than 2% of reads in duck feces but in 100% of reads in turkey tracheal specimens collected at the same time. Further variations in length were observed in NA from turkeys 8 days later. Similarly, minority mutants emerged on the hemagglutinin (HA) gene, with substitutions mostly in the receptor binding site on the globular head. These critical changes suggest a strong evolutionary pressure in turkeys. The increasing performances of next-generation sequencing technologies should enable us to monitor the genomic diversity of avian influenza viruses and early emergence of potentially pathogenic variants within bird flocks. The present study, based on 454 pyrosequencing, suggests that NA deletion, an example of AIV adaptation from waterfowl to domestic poultry, occurs by selection rather than
de novo
emergence of viral mutants.
Assessment of Whole-Genome Mapping in a Well-Defined Outbreak of Salmonella enterica Serotype Saintpaul
Authors: Fey P. D. , Iwen P. C. , Zentz E. B. , Briska A. M. , Henkhaus J. K. , Bryant K. A. , Larson M. A , Noel R. K. , Hinrichs S. H. 
Published: June 2012

ABSTRACT

We investigated the use of whole-genome mapping and pulsed-field gel electrophoresis (PFGE) with isolates from an outbreak of
Salmonella enterica
serotype Saintpaul. PFGE and whole-genome mapping were concordant with 22 of 23 isolates. Whole-genome mapping is a viable alternative tool for the epidemiological analysis of
Salmonella
food-borne disease investigations.
Optimization of the Preanalytical Steps of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Identification Provides a Flexible and Efficient Tool for Identification of Clinical Yeast Isolates in Medical Laboratories
Authors: Goyer Marianne , Lucchi Geraldine , Ducoroy Patrick , Vagner Odile , Bonnin Alain , Dalle Frederic 
Published: June 2012

ABSTRACT
We report here that modifications of the preanalytical steps of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) identification of yeasts, with regard to the original protocol provided by the manufacturers, appear to be efficient for the reliable routine identification of clinical yeast isolates in medical laboratories. Indeed, when one colony was sampled instead of five and the protein extraction protocol was modified, the performance of MALDI-TOF MS was superior to that of the API ID 32C method (discrepancies were confirmed by using molecular identification), allowing the correct identification of 94% of the 335 clinical isolates prospectively tested. We then demonstrated that the time for which the primary cultures were preincubated on CHROMagar did not impact the identification of yeasts by MALDI-TOF MS, since 95.1 and 96.2% of the 183 clinical yeast isolates prospectively tested were correctly identified after 48 and 72 h of preincubation, respectively.
Critical Analysis of Rhinovirus RNA Load Quantification by Real-Time Reverse Transcription-PCR
Authors: Schibler Manuel , Yerly Sabine , Vieille Gaël , Docquier Mylène , Turin Lara , Kaiser Laurent , Tapparel Caroline 
Published: June 2012

ABSTRACT

Rhinoviruses are the most frequent cause of human respiratory infections, and quantitative rhinovirus diagnostic tools are needed for clinical investigations. Although results obtained by real-time reverse-transcription PCR (RT-PCR) assays are frequently converted to viral RNA loads, this presents several limitations regarding accurate virus RNA quantification, particularly given the need to reliably quantify all known rhinovirus genotypes with a single assay. Using an internal extraction control and serial dilutions of an
in vitro
-transcribed rhinovirus RNA reference standard, we validated a quantitative one-step real-time PCR assay. We then used chimeric rhinovirus genomes with 5′-untranslated regions (5′UTRs) originating from the three rhinovirus species and from one enterovirus to estimate the impact of the 5′UTR diversity. Respiratory specimens from infected patients were then also analyzed. The assay quantification ability ranged from 4.10 to 9.10 log RNA copies/ml, with an estimated error margin of ±10%. This variation was mainly linked to target variability and interassay variability. Taken together, our results indicate that our assay can reliably estimate rhinovirus RNA load, provided that the appropriate error margin is used. In contrast, due to the lack of a universal rhinovirus RNA standard and the variability related to sample collection procedures, accurate absolute rhinovirus RNA quantification in respiratory specimens is currently hardly feasible.