bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coagulation status after therapeutic plasma exchange using citrate in kidney transplant recipients
Authors: Yamada Chisa , Pipe Steven W. , Zhao Lili , Leichtman Alan B. , Samaniego Milagros , Sung Randall S. , Davenport Robertson D. 
Published: September 2016

BACKGROUNDTherapeutic plasma exchange (TPE) is increasingly used for treatment of antibody‐mediated rejection (AMR) after solid organ transplants. There is concern that TPE may increase risk of bleeding, although data are limited. After TPE, clot‐based coagulation tests may not accurately represent the levels of coagulation factors due to the effect of citrate. We investigated protein levels of fibrinogen using antigen detection method (FibAg) and correlated results with a clot‐based fibrinogen activity test (Fib).STUDY DESIGN AND METHODSNine kidney transplant recipients who received TPE for AMR were investigated. Fib, FibAg, prothrombin time/international normalized ratio (PT/INR), partial thromboplastin time (PTT), coagulation factor X chromogenic activity (CFX), and ionized calcium (iCa) were measured at pre‐ and post‐TPE and 1, 3, 6, 9, 24, and 48 hours after the first TPE.RESULTSMean Fib/FibAg ratio before TPE was 1.08; therefore, all Fib values were normalized (n) by dividing by 1.08. Overall, the mean normalized Fib (nFib)/FibAg ratio at post‐TPE was 0.89 and returned to close to 1.0 at 6 hours after the first TPE. Decreases in nFib, FibAg, and CFX and increases in PT/INR and PTT post‐TPE were observed. The lowest Fib, FibAg, CFX, platelet, and iCa levels were still at levels that would be considered sufficient for hemostasis at all time points.CONCLUSIONThe mean nFib/FibAg ratio after TPE was 0.89 and normalized in 6 hours, which demonstrates a persistent effect of citrate for up to 6 hours. Therefore, similar data observed in clot‐based tests of PT/INR and PTT may be falsely elevated up to 6 hours after TPE due to the citrate effect.
Ex Vivo
Maturation Assay for Testing Antimalarial Sensitivity of Rodent Malaria Parasites
Authors: Chang Zi Wei , Malleret Benoit , Russell Bruce , Rénia Laurent , Claser Carla 
Published: September 2016

ABSTRACT

Ex vivo
assay systems provide a powerful approach to studying human malaria parasite biology and to testing antimalarials. For rodent malaria parasites, short-term
in vitro
culture and
ex vivo
antimalarial susceptibility assays are relatively cumbersome, relying on
in vivo
passage for synchronization, since ring-stage parasites are an essential starting material. Here, we describe a new approach based on the enrichment of ring-stage
Plasmodium berghei
,
P. yoelii
, and
P. vinckei vinckei
using a single-step Percoll gradient. Importantly, we demonstrate that the enriched ring-stage parasites develop synchronously regardless of the parasite strain or species used. Using a flow cytometry assay with Hoechst and ethidium or MitoTracker dye, we show that parasite development is easily and rapidly monitored. Finally, we demonstrate that this approach can be used to screen antimalarial drugs.
Prospective Cohort Study of the Relative Abundance of Extended-Spectrum-Beta-Lactamase-Producing Escherichia coli in the Gut of Patients Admitted to Hospitals
Authors: de Lastours Victoire , Chopin Dorothée , Jacquier Hervé , d'Humières Camille , Burdet Charles , Chau Françoise , Denamur Erick , Fantin Bruno 
Published: September 2016

ABSTRACT

A total of 458 patients were prospectively included at hospital admission and screened for extended-spectrum-beta-lactamase-producing (ESBL)
Escherichia coli
carriage in 2007 and in 2010 to 2012. A 4-fold increase in ESBL carriage (3% to 12%), a 5-fold increase in numbers of community patients among ESBL carriers, and a higher number of multiple ESBL strains was found in the 2010 to 2012 period. ESBL
E. coli
represented the dominant
E. coli
strain (relative abundance, >50%) in 10/32 (31%) of ESBL carriers. This represents a major threat in terms of infectious risk and dissemination.
Genomic Characterization of Colistin Heteroresistance in Klebsiella pneumoniae during a Nosocomial Outbreak
Authors: Halaby Teysir , Kucukkose Emre , Janssen Axel B. , Rogers Malbert R. C. , Doorduijn Dennis J. , van der Zanden Adri G. M. , al Naiemi Nashwan , Vandenbroucke-Grauls Christina M. J. E. , van Schaik Willem 
Published: September 2016

ABSTRACT

Klebsiella pneumoniae
is emerging as an important nosocomial pathogen due to its rapidly increasing multidrug resistance, which has led to a renewed interest in polymyxin antibiotics, such as colistin, as antibiotics of last resort. However, heteroresistance (i.e., the presence of a subpopulation of resistant bacteria in an otherwise susceptible culture) may hamper the effectiveness of colistin treatment in patients. In a previous study, we showed that colistin resistance among extended-spectrum-beta-lactamase (ESBL)-producing
K. pneumoniae
isolates emerged after the introduction of selective digestive tract decontamination (SDD) in an intensive care unit (ICU). In this study, we investigated heteroresistance to colistin among ESBL-producing
K. pneumoniae
isolates by using population analysis profiles (PAPs). We used whole-genome sequencing (WGS) to identify the mutations that were associated with the emergence of colistin resistance in these
K. pneumoniae
isolates. We found five heteroresistant subpopulations, with colistin MICs ranging from 8 to 64 mg/liter, which were derived from five clonally related, colistin-susceptible clinical isolates. WGS revealed the presence of mutations in the
lpxM
,
mgrB
,
phoQ
, and
yciM
genes in colistin-resistant
K. pneumoniae
isolates. In two strains,
mgrB
was inactivated by an IS
3
-like or IS
Kpn14
insertion sequence element. Complementation in
trans
with the wild-type
mgrB
gene resulted in these strains reverting to colistin susceptibility. The MICs for colistin-susceptible strains increased 2- to 4-fold in the presence of the mutated
phoQ
,
lpxM
, and
yciM
alleles. In conclusion, the present study indicates that heteroresistant
K. pneumoniae
subpopulations may be selected for upon exposure to colistin. Mutations in
mgrB
and
phoQ
have previously been associated with colistin resistance, but we provide experimental evidence for roles of mutations in the
yciM
and
lpxM
genes in the emergence of colistin resistance in
K. pneumoniae
.
Disruption of Membrane by Colistin Kills Uropathogenic Escherichia coli Persisters and Enhances Killing of Other Antibiotics
Authors: Cui Peng , Niu Hongxia , Shi Wanliang , Zhang Shuo , Zhang Hao , Margolick Joseph , Zhang Wenhong , Zhang Ying 
Published: September 2016

ABSTRACT

Persisters are small populations of quiescent bacterial cells that survive exposure to bactericidal antibiotics and are responsible for many persistent infections and posttreatment relapses. However, little is known about how to effectively kill persister bacteria. In the work presented here, we found that colistin, a membrane-active antibiotic, was highly active against
Escherichia coli
persisters at high concentrations (25 or 50 μg/ml). At a clinically relevant lower concentration (10 μg/ml), colistin alone had no apparent effect on
E. coli
persisters. In combination with other drugs, this concentration of colistin enhanced the antipersister activity of gentamicin and ofloxacin but not that of ampicillin, nitrofurans, and sulfa drugs
in vitro
. The colistin enhancement effect was most likely due to increased uptake of the other antibiotics, as demonstrated by increased accumulation of fluorescence-labeled gentamicin. Interestingly, colistin significantly enhanced the activity of ofloxacin and nitrofurantoin but not that of gentamicin or sulfa drugs in the murine model of urinary tract infection. Our findings suggest that targeting bacterial membranes is a valuable approach to eradicating persisters and should have implications for more effective treatment of persistent bacterial infections.
Posaconazole Tablet Formulation at 400 Milligrams Daily Achieves Desired Minimum Serum Concentrations in Adult Patients with a Hematologic Malignancy or Stem Cell Transplant
Authors: Pham Aaron N. , Bubalo Joseph S. , Lewis James S. 
Published: September 2016

ABSTRACT
We describe our experience using the posaconazole 400-mg delayed-release tablet formulation once daily in 20 patients with hematologic malignancy or hematopoietic stem cell transplant who were unable to attain prespecified target minimum serum (trough) concentrations for treatment or prophylaxis of invasive fungal infection. The higher dose allowed the majority of patients to achieve prespecified target trough concentrations without incurring additional toxicities.
Antileishmanial Activity of Ezetimibe: Inhibition of Sterol Biosynthesis,
In Vitro
Synergy with Azoles, and Efficacy in Experimental Cutaneous Leishmaniasis
Authors: Andrade-Neto Valter Viana , Cunha-Júnior Edézio Ferreira , Canto-Cavalheiro Marilene Marcuzzo do , Atella Geórgia Correa , Fernandes Talita de Almeida , Costa Paulo Roberto Ribeiro , Torres-Santos Eduardo Caio 
Published: September 2016

ABSTRACT

Leishmaniasis affects mainly low-income populations in tropical regions. Radical innovation in drug discovery is time-consuming and expensive, imposing severe restrictions on the ability to launch new chemical entities for the treatment of neglected diseases. Drug repositioning is an attractive strategy for addressing a specific demand more easily. In this project, we have evaluated the antileishmanial activities of 30 drugs currently in clinical use for various morbidities. Ezetimibe, clinically used to reduce intestinal cholesterol absorption in dyslipidemic patients, killed
Leishmania amazonensis
promastigotes with a 50% inhibitory concentration (IC
50
) of 30 μM. Morphological analysis revealed that ezetimibe caused the parasites to become rounded, with multiple nuclei and flagella. Analysis by gas chromatography (GC)-mass spectrometry (MS) showed that promastigotes treated with ezetimibe had smaller amounts of C-14-demethylated sterols, and accumulated more cholesterol and lanosterol, than untreated promastigotes. We then evaluated the combination of ezetimibe with well-known antileishmanial azoles. The fractional inhibitory concentration index (FICI) indicated synergy when ezetimibe was combined with ketoconazole or miconazole. The activity of ezetimibe against intracellular amastigotes was confirmed, with an IC
50
of 20 μM, and ezetimibe reduced the IC
90
s of ketoconazole and miconazole from 11.3 and 11.5 μM to 4.14 and 8.25 μM, respectively. Subsequently, we confirmed the activity of ezetimibe
in vivo
, showing that it decreased lesion development and parasite loads in murine cutaneous leishmaniasis. We concluded that ezetimibe has promising antileishmanial activity and should be considered in combination with azoles in further preclinical and clinical studies.
Distinct Prominent Roles for Enzymes of Plasmodium berghei Heme Biosynthesis in Sporozoite and Liver Stage Maturation
Authors: Rizopoulos Zaira , Matuschewski Kai , Haussig Joana M. 
Published: September 2016

ABSTRACT

Malarial parasites have evolved complex regulation of heme supply and disposal to adjust to heme-rich and -deprived host environments. In addition to its own pathway for heme biosynthesis,
Plasmodium
likely harbors mechanisms for heme scavenging from host erythrocytes. Elaborate compartmentalization of
de novo
heme synthesis into three subcellular locations, including the vestigial plastid organelle, indicates critical roles in life cycle progression. In this study, we systematically profile the essentiality of heme biosynthesis by targeted gene deletion of enzymes in early steps of this pathway. We show that disruption of endogenous heme biosynthesis leads to a first detectable defect in oocyst maturation and sporogony in the
Anopheles
vector, whereas blood stage propagation, colonization of mosquito midguts, or initiation of oocyst development occurs indistinguishably from that of wild-type parasites. Although sporozoites are produced by parasites lacking an intact pathway for heme biosynthesis, they are absent from mosquito salivary glands, indicative of a vital role for heme biosynthesis only in sporozoite maturation. Rescue of the first defect in sporogony permitted analysis of potential roles in liver stages. We show that liver stage parasites benefit from but do not strictly depend upon their own aminolevulinic acid synthase and that they can scavenge aminolevulinic acid from the host environment. Together, our experimental genetics analysis of
Plasmodium
enzymes for heme biosynthesis exemplifies remarkable shifts between the use of endogenous and host resources during life cycle progression.
The Adherent/Invasive Escherichia coli Strain LF82 Invades and Persists in Human Prostate Cell Line RWPE-1, Activating a Strong Inflammatory Response
Authors: Conte Maria P. , Aleandri Marta , Marazzato Massimiliano , Conte Antonietta L. , Ambrosi Cecilia , Nicoletti Mauro , Zagaglia Carlo , Gambara Guido , Palombi Fioretta , De Cesaris Paola , Ziparo Elio , Palamara Anna T. , Riccioli Anna , Longhi Catia 
Published: September 2016

ABSTRACT

Adherent/invasive
Escherichia coli
(AIEC) strains have recently been receiving increased attention because they are more prevalent and persistent in the intestine of Crohn's disease (CD) patients than in healthy subjects. Since AIEC strains show a high percentage of similarity to extraintestinal pathogenic
E. coli
(ExPEC), neonatal meningitis-associated
E. coli
(NMEC), and uropathogenic
E. coli
(UPEC) strains, here we compared AIEC strain LF82 with a UPEC isolate (strain EC73) to assess whether LF82 would be able to infect prostate cells as an extraintestinal target. The virulence phenotypes of both strains were determined by using the RWPE-1 prostate cell line. The results obtained indicated that LF82 and EC73 are able to adhere to, invade, and survive within prostate epithelial cells. Invasion was confirmed by immunofluorescence and electron microscopy. Moreover, cytochalasin D and colchicine strongly inhibited bacterial uptake of both strains, indicating the involvement of actin microfilaments and microtubules in host cell invasion. Moreover, both strains belong to phylogenetic group B2 and are strong biofilm producers.
In silico
analysis reveals that LF82 shares with UPEC strains several virulence factors: namely, type 1 pili, the group II capsule, the vacuolating autotransporter toxin, four iron uptake systems, and the pathogenic island (PAI). Furthermore, compared to EC73, LF82 induces in RWPE-1 cells a marked increase of phosphorylation of mitogen-activated protein kinases (MAPKs) and of NF-κB already by 5 min postinfection, thus inducing a strong inflammatory response. Our
in vitro
data support the hypothesis that AIEC strains might play a role in prostatitis, and, by exploiting host-cell signaling pathways controlling the innate immune response, likely facilitate bacterial multiplication and dissemination within the male genitourinary tract.
Identification of a Novel
N
-Acetylmuramic Acid Transporter in Tannerella forsythia
Authors: Ruscitto Angela , Hottmann Isabel , Stafford Graham P. , Schäffer Christina , Mayer Christoph , Sharma Ashu 
Published: September 2016

ABSTRACT

Tannerella forsythia
is a Gram-negative periodontal pathogen lacking the ability to undergo
de novo
synthesis of amino sugars
N
-acetylmuramic acid (MurNAc) and
N
-acetylglucosamine (GlcNAc) that form the disaccharide repeating unit of the peptidoglycan backbone.
T. forsythia
relies on the uptake of these sugars from the environment, which is so far unexplored. Here, we identified a novel transporter system of
T. forsythia
involved in the uptake of MurNAc across the inner membrane and characterized a homolog of the
Escherichia coli
MurQ etherase involved in the conversion of MurNAc-6-phosphate (MurNAc-6-P) to GlcNAc-6-P. The genes encoding these components were identified on a three-gene cluster spanning Tanf_08375 to Tanf_08385 located downstream from a putative peptidoglycan recycling locus. We show that the three genes, Tanf_08375, Tanf_08380, and Tanf_08385, encoding a MurNAc transporter, a putative sugar kinase, and a MurQ etherase, respectively, are transcriptionally linked. Complementation of the Tanf_08375 and Tanf_08380 genes together in
trans
, but not individually, rescued the inability of an
E. coli
mutant deficient in the phosphotransferase (PTS) system-dependent MurNAc transporter MurP as well as that of a double mutant deficient in MurP and components of the PTS system to grow on MurNAc. In addition, complementation with this two-gene construct in
E. coli
caused depletion of MurNAc in the medium, further confirming this observation. Our results show that the products of Tanf_08375 and Tanf_08380 constitute a novel non-PTS MurNAc transporter system that seems to be widespread among bacteria of the
Bacteroidetes
phylum. To the best of our knowledge, this is the first identification of a PTS-independent MurNAc transporter in bacteria.

IMPORTANCE
In this study, we report the identification of a novel transporter for peptidoglycan amino sugar
N
-acetylmuramic acid (MurNAc) in the periodontal pathogen
T. forsythia
. It has been known since the late 1980s that
T. forsythia
is a MurNAc auxotroph relying on environmental sources for this essential sugar. Most sugar transporters, and the MurNAc transporter MurP in particular, require a PTS phosphorelay to drive the uptake and concurrent phosphorylation of the sugar through the inner membrane in Gram-negative bacteria. Our study uncovered a novel type of PTS-independent MurNAc transporter, and although so far, it seems to be unique to
T. forsythia
, it may be present in a range of bacteria both of the oral cavity and gut, especially of the phylum
Bacteroidetes
.
Horizontal Transfer of the Salmonella enterica Serovar Infantis Resistance and Virulence Plasmid pESI to the Gut Microbiota of Warm-Blooded Hosts
Authors: Aviv Gili , Rahav Galia , Gal-Mor Ohad 
Published: September 2016

ABSTRACT

Salmonella enterica
serovar Infantis is one of the prevalent salmonellae worldwide. Recently, we showed that the emergence of
S
. Infantis in Israel was facilitated by the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Here we elucidate the ecology, transmission properties, and regulation of pESI. We show that despite its large size (~280 kb), pESI does not impose a significant metabolic burden
in vitro
and that it has been recently fixed in the domestic
S
. Infantis population. pESI conjugation and the transcription of its pilus (
pil
) genes are inhibited at the ambient temperature (27°C) and by ≥1% bile but increased under temperatures of 37 to 41°C, oxidative stress, moderate osmolarity, and the microaerobic conditions characterizing the intestinal environment of warm-blooded animals. The pESI-encoded protein TraB and the oxygen homeostasis regulator Fnr were identified as transcriptional regulators of pESI conjugation. Using the mouse model, we show that following
S
. Infantis infection, pESI can be horizontally transferred to the gut microbiota, including to commensal
Escherichia coli
strains. Possible transfer, but not persistence, of pESI was also observed into Gram-positive mouse microbiota species, especially
Lactobacillus reuteri
. Moreover, pESI was demonstrated to further disseminate from gut microbiota to
S. enterica
serovar Typhimurium, in the context of gastrointestinal infection. These findings exhibit the ability of a selfish clinically relevant megaplasmid to distribute to and from the microbiota and suggest an overlooked role of the microbiota as a reservoir of mobile genetic elements and intermediator in the spread of resistance and virulence genes between commensals and pathogenic bacteria.

IMPORTANCE
Plasmid conjugation plays a key role in microbial evolution, enabling the acquisition of new phenotypes, including resistance and virulence.
Salmonella enterica
serovar Infantis is one of the ubiquitous salmonellae worldwide and a major cause of foodborne infections. Previously, we showed that the emergence of
S
. Infantis in Israel has involved the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Recently, the emergence of another
S
. Infantis strain carrying a pESI-like plasmid was identified in Italy, suggesting that the acquisition of pESI may be common to different emergent
S
. Infantis populations globally. Transmission of this plasmid to other strains or bacterial species is an alarming scenario. Understanding the ecology, regulation, and transmission properties of clinically relevant plasmids and the role of the microbiota in their spreading offers a new mechanism explaining the emergence of new pathogenic and resistant biotypes and may assist in the development of appropriate surveillance and prevention measures.
Interseason variability of a functional movement test, the 9+ screening battery, in professional male football players
Authors: Bakken A , Targett S , Bere T , Eirale C , Farooq A , Tol J L , Whiteley R , Witvrouw E , Khan K M , Bahr R 
Published: September 2016

BackgroundThe Nine Plus screening battery test (9+) is a functional movement test intended to identify limitations in fundamental movement patterns predisposing athletes to injury. However, the interseason variability is unknown.AimTo examine the variability of the 9+ test between 2 consecutive seasons in professional male football players.MethodsAsymptomatic Qatar Star League players (n=220) completed the 9+ at the beginning of the 2013 and 2014 seasons. Time-loss injuries in training and matches were obtained from the Aspetar Injury and Illness Surveillance Program. No intervention was initiated between test occasions.ResultsA significant increase in the mean total score of 1.6 points (95% CI 1.0 to 2.2, p<0.001) was found from season 1 (22.2±4.1 (SD)) to season 2 (23.8±3.3). The variability was large, as shown by an intraclass correlation coefficient (ICC) of 0.24 (95% CI 0.11 to 0.36) and a minimal detectable change (MDC) of 8.7 points. Of the 220 players, 136 (61.8%) suffered a time-loss injury between the 2 tests. There was an improvement in mean total scores in the injured (+2.0±0.4 (SE), p<0.001) group but not in the uninjured group (+0.9±0.5, p=0.089). The variability from season 1 to season 2 was large both in the injured (ICC 0.25, 0.09 to 0.40, MDC 8.3) and uninjured (ICC 0.24, 0.02 to 0.43, MDC 9.1) groups.ConclusionsThe 9+ demonstrated substantial intraindividual variability in the total score between 2 consecutive seasons, irrespective of injury. A change above 8 points is necessary to represent a real change in the 9+ test between seasons.