bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationship between Fosfomycin Exposure and Amplification of Escherichia coli Subpopulations with Reduced Susceptibility in a Hollow-Fiber Infection Model
Authors: VanScoy Brian , McCauley Jennifer , Bhavnani Sujata M. , Ellis-Grosse Evelyn J. , Ambrose Paul G. 
Published: June 2016

ABSTRACT

Understanding the relationship between antibiotic exposure and amplification of bacterial subpopulations with reduced drug susceptibility over time is important for evaluating the adequacy of dosing regimens. We utilized a hollow-fiber infection model to identify the fosfomycin intravenous dosing regimens that prevented the amplification of
Escherichia coli
bacterial subpopulations with reduced fosfomycin susceptibility. The challenge isolate was
E. coli
ATCC 25922 (agar MIC with glucose-6-phosphate, 1 mg/liter; agar MIC without glucose-6-phosphate, 32 mg/liter). The fosfomycin dosing regimens studied were 1 to 12 g every 8 h for 10 days to approximate that planned for clinical use. The studies included a no-treatment control regimen. Two bacterial subpopulations were identified, one with reduced susceptibility with agar MIC values ranging from 32 to 128 mg/liter and the other resistant with agar MIC values of 256 to >1,024 mg/liter on plates containing 5× and 256× the baseline MIC value, respectively. An inverted-U-shaped function best described the relationship between the amplification of the two bacterial subpopulations and drug exposure. The lowest fosfomycin dosing regimen that did not amplify a bacterial subpopulation with reduced susceptibility was 4 g administered every 8 h. Nearly immediate amplification of bacterial subpopulations with reduced susceptibility was observed with fosfomycin dosing regimens consisting of 1 to 2 g every 8 h. These data will be useful to support the selection of fosfomycin dosing regimens that minimize the potential for on-therapy amplification of bacterial subpopulations with reduced susceptibility.
In Vitro
Characterization of Human Cytomegalovirus-Targeting Therapeutic Monoclonal Antibodies LJP538 and LJP539
Authors: Patel Hetalkumar D. , Nikitin Pavel , Gesner Thomas , Lin James J. , Barkan David T. , Ciferri Claudio , Carfi Andrea , Akbarnejad Yazdi Tahmineh , Skewes-Cox Peter , Wiedmann Brigitte , Jarousse Nadine , Zhong Weidong , Feire Adam , Hebner Christy M. 
Published: June 2016

ABSTRACT

Human cytomegalovirus (HCMV) infection is usually benign in healthy individuals but can cause life-threatening disease in those with compromised immune systems. Approved drugs available to treat HCMV disease, including ganciclovir, cidofovir, and foscarnet, have significant toxicities that limit their use in certain patient populations. LJP538 and LJP539 are human monoclonal antibodies that are being evaluated as immunoglobulin therapeutics. The antibodies target glycoproteins gB and the gH/gL/UL128/UL130/UL131a pentameric complex, respectively. Here we present an
in vitro
characterization of these antibodies. We show that LJP538 and LJP539 are more potent than a marketed immunoglobulin at inhibiting HCMV infection of various cell lines relevant to pathogenesis. We find that LJP538 and LJP539 are active against a panel of clinical isolates
in vitro
and demonstrate minor-to-moderate synergy in combination. Passage of HCMV in the presence of LJP538 or LJP539 alone resulted in resistance-associated mutations that mapped to the target genes. However, no loss of susceptibility to the combination of antibodies was observed for >400 days in culture. Finally, the binding regions of LJP538 and LJP539 are conserved among clinical isolates. Taken together, these data support the use of LJP538 and LJP539 in combination for clinical trials in HCMV patients.
Serum Albumin and Ca
2+
Are Natural Competence Inducers in the Human Pathogen Acinetobacter baumannii
Authors: Traglia German Matias , Quinn Brettni , Schramm Sareda T. J. , Soler-Bistue Alfonso , Ramirez Maria Soledad 
Published: June 2016

ABSTRACT

The increasing frequency of bacteria showing antimicrobial resistance (AMR) raises the menace of entering into a postantibiotic era. Horizontal gene transfer (HGT) is one of the prime reasons for AMR acquisition.
Acinetobacter baumannii
is a nosocomial pathogen with outstanding abilities to survive in the hospital environment and to acquire resistance determinants. Its capacity to incorporate exogenous DNA is a major source of AMR genes; however, few studies have addressed this subject. The transformation machinery as well as the factors that induce natural competence in
A. baumannii
are unknown. In this study, we demonstrate that naturally competent strain A118 increases its natural transformation frequency upon the addition of Ca
2+
or albumin. We show that
comEA
and
pilQ
are involved in this process since their expression levels are increased upon the addition of these compounds. An unspecific protein, like casein, does not reproduce this effect, showing that albumin's effect is specific. Our work describes the first specific inducers of natural competence in
A. baumannii
. Overall, our results suggest that the main protein in blood enhances HGT in
A. baumannii
, contributing to the increase of AMR in this threatening human pathogen.
Antimalarial Benzoxaboroles Target Plasmodium falciparum Leucyl-tRNA Synthetase
Authors: Sonoiki Ebere , Palencia Andres , Guo Denghui , Ahyong Vida , Dong Chen , Li Xianfeng , Hernandez Vincent S. , Zhang Yong-Kang , Choi Wai , Gut Jiri , Legac Jennifer , Cooper Roland , Alley M. R. K. , Freund Yvonne R. , DeRisi Joseph , Cusack Stephen , Rosenthal Philip J. 
Published: June 2016

ABSTRACT

There is a need for new antimalarials, ideally with novel mechanisms of action. Benzoxaboroles have been shown to be active against bacteria, fungi, and trypanosomes. Therefore, we investigated the antimalarial activity and mechanism of action of 3-aminomethyl benzoxaboroles against
Plasmodium falciparum
. Two 3-aminomethyl compounds, AN6426 and AN8432, demonstrated good potency against cultured multidrug-resistant (W2 strain)
P. falciparum
(50% inhibitory concentration [IC
50
] of 310 nM and 490 nM, respectively) and efficacy against murine
Plasmodium berghei
infection when administered orally once daily for 4 days (90% effective dose [ED
90
], 7.4 and 16.2 mg/kg of body weight, respectively). To characterize mechanisms of action, we selected parasites with decreased drug sensitivity by culturing with stepwise increases in concentration of AN6426. Resistant clones were characterized by whole-genome sequencing. Three generations of resistant parasites had polymorphisms in the predicted editing domain of the gene encoding a
P. falciparum
leucyl-tRNA synthetase (LeuRS; PF3D7_0622800) and in another gene (PF3D7_1218100), which encodes a protein of unknown function. Solution of the structure of the
P. falciparum
LeuRS editing domain suggested key roles for mutated residues in LeuRS editing. Short incubations with AN6426 and AN8432, unlike artemisinin, caused dose-dependent inhibition of [
14
C]leucine incorporation by cultured wild-type, but not resistant, parasites. The growth of resistant, but not wild-type, parasites was impaired in the presence of the unnatural amino acid norvaline, consistent with a loss of LeuRS editing activity in resistant parasites. In summary, the benzoxaboroles AN6426 and AN8432 offer effective antimalarial activity and act, at least in part, against a novel target, the editing domain of
P. falciparum
LeuRS.
EseE of Edwardsiella tarda Augments Secretion of Translocon Protein EseC and Expression of the
escC
-
eseE
Operon
Authors: Yi Jia , Xiao Shui Bing , Zeng Zhi Xiong , Lu Jin Fang , Liu Lu Yi , Laghari Zubair Ahmed , Nie Pin , Yu Hong Bing , Xie Hai Xia 
Published: June 2016

ABSTRACT

Edwardsiella tarda
is an important Gram-negative pathogen that employs a type III secretion system (T3SS) to deliver effectors into host cells to facilitate bacterial survival and replication. These effectors are translocated into host cells through a translocon complex composed of three secreted proteins, namely, EseB, EseC, and EseD. The secretion of EseB and EseD requires a chaperone protein called EscC, whereas the secretion of EseC requires the chaperone EscA. In this study, we identified a novel protein (EseE) that also regulates the secretion of EseC. An
eseE
deletion mutant secreted much less EseC into supernatants, accompanied by increased EseC levels within bacterial cells. We also demonstrated that EseE interacted directly with EseC in a pulldown assay. Interestingly, EseC, EseE, and EscA were able to form a ternary complex, as revealed by pulldown and gel filtration assays. Of particular importance, the deletion of
eseE
resulted in decreased levels of EseB and EseD proteins in both the bacterial pellet and supernatant fraction. Furthermore, real-time PCR assays showed that EseE positively regulated the transcription of the translocon operon
escC
-
eseE
, comprising
escC
,
eseB
,
escA
,
eseC
,
eseD
, and
eseE
. These effects of EseE on the translocon components/operon appeared to have a functional consequence, since the Δ
eseE
strain was outcompeted by wild-type
E. tarda
in a mixed infection in blue gourami fish. Collectively, our results demonstrate that EseE not only functions as a chaperone for EseC but also acts as a positive regulator controlling the expression of the translocon operon
escC-eseE
, thus contributing to the pathogenesis of
E. tarda
in fish.
Interleukin-17 Pathophysiology and Therapeutic Intervention in Cystic Fibrosis Lung Infection and Inflammation
Authors: Hsu Daniel , Taylor Patricia , Fletcher Dave , van Heeckeren Rolf , Eastman Jean , van Heeckeren Anna , Davis Pamela , Chmiel James F. , Pearlman Eric , Bonfield Tracey L. 
Published: June 2016

ABSTRACT

Cystic fibrosis (CF) is characterized by an excessive neutrophilic inflammatory response within the airway as a result of defective cystic fibrosis transmembrane receptor (CFTR) expression and function. Interleukin-17A induces airway neutrophilia and mucin production associated with
Pseudomonas aeruginosa
colonization, which is associated with the pathophysiology of cystic fibrosis. The objectives of this study were to use the preclinical murine model of cystic fibrosis lung infection and inflammation to investigate the role of IL-17 in CF lung pathophysiology and explore therapeutic intervention with a focus on IL-17.
Cftr
-deficient mice (CF mice) and wild-type mice (WT mice) infected with
P. aeruginosa
had robust IL-17 production early in the infection associated with a persistent elevated inflammatory response. Intratracheal administration of IL-17 provoked a neutrophilic response in the airways of WT and CF animals which was similar to that observed with
P. aeruginosa
infection. The neutralization of IL-17 prior to infection significantly improved the outcomes in the CF mice, suggesting that IL-17 may be a therapeutic target. We demonstrate in this report that the pathophysiological contribution of IL-17 may be due to the induction of chemokines from the epithelium which is augmented by a deficiency of
Cftr
and ongoing inflammation. These studies demonstrate the
in vivo
contribution of IL-17 in cystic fibrosis lung disease and the therapeutic validity of attenuating IL-17 activity in cystic fibrosis.
Investigating the Relatedness of Enteroinvasive Escherichia coli to Other E. coli and Shigella Isolates by Using Comparative Genomics
Authors: Hazen Tracy H. , Leonard Susan R. , Lampel Keith A. , Lacher David W. , Maurelli Anthony T. , Rasko David A. 
Published: June 2016

ABSTRACT

Enteroinvasive
Escherichia coli
(EIEC) is a unique pathovar that has a pathogenic mechanism nearly indistinguishable from that of
Shigella
species. In contrast to isolates of the four
Shigella
species, which are widespread and can be frequent causes of human illness, EIEC causes far fewer reported illnesses each year. In this study, we analyzed the genome sequences of 20 EIEC isolates, including 14 first described in this study. Phylogenomic analysis of the EIEC genomes demonstrated that 17 of the isolates are present in three distinct lineages that contained only EIEC genomes, compared to reference genomes from each of the
E. coli
pathovars and
Shigella
species. Comparative genomic analysis identified genes that were unique to each of the three identified EIEC lineages. While many of the EIEC lineage-specific genes have unknown functions, those with predicted functions included a colicin and putative proteins involved in transcriptional regulation or carbohydrate metabolism.
In silico
detection of the
Shigella
virulence plasmid (pINV), which is essential for the invasion of host cells, demonstrated that a form of pINV was present in nearly all EIEC genomes, but the Mxi-Spa-Ipa region of the plasmid that encodes the invasion-associated proteins was absent from several of the EIEC isolates. The comparative genomic findings in this study support the hypothesis that multiple EIEC lineages have evolved independently from multiple distinct lineages of
E. coli
via the acquisition of the
Shigella
virulence plasmid and, in some cases, the
Shigella
pathogenicity islands.
HtrA, a Temperature- and Stationary Phase-Activated Protease Involved in Maturation of a Key Microbial Virulence Determinant, Facilitates Borrelia burgdorferi Infection in Mammalian Hosts
Authors: Ye Meiping , Sharma Kavita , Thakur Meghna , Smith Alexis A. , Buyuktanir Ozlem , Xiang Xuwu , Yang Xiuli , Promnares Kamoltip , Lou Yongliang , Yang X. Frank , Pal Utpal 
Published: June 2016

ABSTRACT

High-temperature requirement protease A (HtrA) represents a family of serine proteases that play important roles in microbial biology. Unlike the genomes of most organisms, that of
Borrelia burgdorferi
notably encodes a single HtrA gene product, termed BbHtrA. Previous studies identified a few substrates of BbHtrA; however, their physiological relevance could not be ascertained, as targeted deletion of the gene has not been successful. Here we show that Bb
htrA
transcripts are induced during spirochete growth either in the stationary phase or at elevated temperature. Successful generation of a Bb
htrA
deletion mutant and restoration by genetic complementation suggest a nonessential role for this protease in microbial viability; however, its remarkable growth, morphological, and structural defects during cultivation at 37°C confirm a high-temperature requirement for protease activation and function. The Bb
htrA
-deficient spirochetes were unable to establish infection of mice, as evidenced by assessment of culture, PCR, and serology. We show that transcript abundance as well as proteolytic processing of a borrelial protein required for cell fission and infectivity, BB0323, is impaired in Bb
htrA
mutants grown at 37°C, which likely contributed to their inability to survive in a mammalian host. Together, these results demonstrate the physiological relevance of a unique temperature-regulated borrelial protease, BbHtrA, which further enlightens our knowledge of intriguing aspects of spirochete biology and infectivity.
Genetic and Transcriptional Analyses of the Flagellar Gene Cluster in Actinoplanes missouriensis
Authors: Jang Moon-Sun , Mouri Yoshihiro , Uchida Kaoru , Aizawa Shin-Ichi , Hayakawa Masayuki , Fujita Nobuyuki , Tezuka Takeaki , Ohnishi Yasuo 
Published: June 2016

ABSTRACT

Actinoplanes missouriensis
, a Gram-positive and soil-inhabiting bacterium, is a member of the rare actinomycetes. The filamentous cells produce sporangia, which contain hundreds of flagellated spores that can swim rapidly for a short period of time until they find niches for germination. These swimming cells are called zoospores, and the mechanism of this unique temporal flagellation has not been elucidated. Here, we report all of the flagellar genes in the bacterial genome and their expected function and contribution for flagellar morphogenesis. We identified a large flagellar gene cluster composed of 33 genes that encode the majority of proteins essential for assembling the functional flagella of Gram-positive bacteria. One noted exception to the cluster was the location of the
fliQ
gene, which was separated from the cluster. We examined the involvement of four genes in flagellar biosynthesis by gene disruption,
fliQ
,
fliC
,
fliK
, and
lytA
. Furthermore, we performed a transcriptional analysis of the flagellar genes using RNA samples prepared from
A. missouriensis
grown on a sporangium-producing agar medium for 1, 3, 6, and 40 days. We demonstrated that the transcription of the flagellar genes was activated in conjunction with sporangium formation. Eleven transcriptional start points of the flagellar genes were determined using the rapid amplification of cDNA 5′ ends (RACE) procedure, which revealed the highly conserved promoter sequence CTCA(N
15–17
)GCCGAA. This result suggests that a sigma factor is responsible for the transcription of all flagellar genes and that the flagellar structure assembles simultaneously.

IMPORTANCE
The biology of a zoospore is very interesting from the viewpoint of morphogenesis, survival strategy, and evolution. Here, we analyzed flagellar genes in
A. missouriensis
, which produces sporangia containing hundreds of flagellated spores each. Zoospores released from the sporangia swim for a short time before germination occurs. We identified a large flagellar gene cluster and an orphan flagellar gene (
fliQ
). These findings indicate that the zoospore flagellar components are typical of Gram-positive bacteria. However, the transcriptional analysis revealed that all flagellar genes are transcribed simultaneously during sporangium formation, a pattern differing from the orderly, regulated expression of flagellar genes in other bacteria, such as
Salmonella
and
Escherichia coli
. These results suggest a novel regulatory mechanism for flagellar formation in
A. missouriensis
.
Electronic nicotine delivery system landscape in licensed tobacco retailers: results of a county-level survey in Oklahoma
Authors: Brame L S , Mowls D S , Damphousse K E , Beebe L A 
Published: June 2016

ObjectivesElectronic nicotine delivery systems (ENDS) have recently emerged as a component of the tobacco retail environment. The aims of this study were to describe the availability, types of ENDS and placement of ENDS relative to traditional tobacco products at franchised licensed tobacco retailers and non-franchised licensed tobacco retailers.DesignObservational study.SettingFranchised and non-franchised tobacco retailers in Cleveland County, Oklahoma, USA.Primary and secondary outcome measuresThe number of stores selling ENDS, the variability in brands of ENDS sold, the location of the ENDS within the retailers, the quantity of ENDS sold compared with traditional tobacco products, and the presence of outdoor signage.ResultsData from 57 randomly sampled tobacco retailers were used to describe the presence of ENDS at independent non-franchised and franchised tobacco retailers. The overwhelming majority (90%) of licensed tobacco retailers sold ENDS, and differences were observed between franchised and non-franchised stores. 45 of the 51 retailers (88%) selling ENDS had them placed at the point of sale. 2 of the 21 franchised retailers (9.5%) had ENDS placed at ≤3½ feet above floor level compared to none of the 30 non-franchised retailers (0%).ConclusionsThis small study is the first to characterise ENDS within the tobacco retail environment in a county in Oklahoma, USA. The results from this study demonstrate the complexity of the tobacco retail landscape and generate questions for future studies regarding the incorporation and placement of ENDS in tobacco retail environments.
Longitudinal trends in use and costs of targeted therapies for common cancers in Taiwan: a retrospective observational study
Authors: Hsu Jason C , Lu Christine Y 
Published: June 2016

ObjectivesSome targeted therapies have improved survival and overall quality of cancer care generally, but these increasingly expensive medicines have led to increases in pharmaceutical expenditure. This study examined trends in use and expenditures of antineoplastic agents in Taiwan, and estimated market shares by prescription volume and costs of targeted therapies over time. We also determined which cancer types accounted for the highest use of targeted therapies.DesignThis is a retrospective observational study focusing on the utilisation of targeted therapies for treatment of cancer.SettingThe monthly claims data for antineoplastic agents were retrieved from Taiwan's National Health Insurance Research Database (2009–2012).Main outcome measuresWe calculated market shares by prescription volume and costs for each class of antineoplastic agent by cancer type. Using a time series design with Autoregressive Integrated Moving Average (ARIMA) models, we estimated trends in use and costs of targeted therapies.ResultsAmong all antineoplastic agents, use of targeted therapies grew from 6.24% in 2009 to 12.29% in 2012, but their costs rose from 26.16% to 41.57% in that time. Monoclonal antibodies and protein kinase inhibitors contributed the most (respectively, 23.84% and 16.12% of costs for antineoplastic agents in 2012). During 2009–2012, lung (44.64% of use; 28.26% of costs), female breast (16.49% of use; 27.18% of costs) and colorectal (12.11% of use; 13.16% of costs) cancers accounted for the highest use of targeted therapies.ConclusionsIn Taiwan, targeted therapies are increasingly used for different cancers, representing a substantial economic burden. It is important to establish mechanisms to monitor their use and outcomes.
Improving the quality of handover in a liaison psychiatry team
Authors: Brook Jennifer , Amaro Calcia Marilia 
Published: June 2016

Handover is a high risk point for errors in clinical care, in many cases leading to adverse events or near misses. The timely transfer of accurate and useful information between professionals is vital to ensure quality and safety, and to ensure the transfer of accountability for care.In this project standards were developed for quality handover between doctors in a liaison psychiatry department. The aim of these were to ensure adequate identification of patients, clear communication of tasks to be completed and relevant risk issues, as well as a guide to the priority of jobs. We measured compliance with these standards for all patients documented in the handover book during three week periods in 2013, 2014 (following delivery of education and guidance on handover to all doctors), and finally in 2015 after implementation of a proforma for handover.Handover documentation prior to the implementation of standards was of poor quality with significant absences of information. Key information to identify patients was frequently absent, for example hospital number was only recorded in 1% of cases. Only 81% of entries included the reason for the patient's referral, and 27% made no mention of the outstanding tasks for completion. Despite guidance and education of all doctors regarding the standards, there was no consistent improvement in compliance. It was particularly concerning that risk issues were only mentioned in 18% of cases, even when assessed immediately after education was given. Following introduction of the proforma compliance increased with overall completeness of handover improving from 40% to 71%.Without guidelines handover between shifts is of a poor quality, and often lacks key information to allow colleagues to identify patients and prioritise need. Education of those performing these handovers did not produce any benefits, either immediately following its delivery or in longer term follow up. The implementation of a template to aid clinicians in recording this data did produce improvements and received positive feedback from doctors.