bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequence type 398 meticillin‐resistant Staphylococcus aureus infection in a pet rabbit
Authors: Loncaric Igor , Künzel Frank 
Published: April 2013

BackgroundMeticillin‐resistant Staphylococcus aureus (MRSA) is a frequent pathogen of humans and many animal species, and has become established as a veterinary pathogen.Case reportIn this case report we describe an MRSA infection in a dwarf rabbit, treatment of the infection and, subsequently, the genetic analysis of the isolated strain. The pet rabbit was presented to an animal hospital due to recurrent swellings on the head and on the neck. Bacteriological examination yielded Staphylococcus aureus, which was resistant to β‐lactam antibiotics. The isolate was confirmed as an MRSA by mecA PCR, Panton‐Valentine leukocidin (PVL) negative, and typed as multilocus sequence type (ST)398/staphylococcal protein A (spa) type t011/staphylococcal cassette chromosome mec (SCCmec) type SCCmecIVa. The rabbit was treated with rifampicin for 2 weeks. After 2.5 weeks the rabbit was clinically normal and control swabs were negative for MRSA.Conclusions and clinical importanceThis study is the first to report MRSA in a rabbit in Austria. This study contributes to the growing evidence that MRSA ST398 could be isolated from a variety of animals.
Study to assessin vitroantimicrobial activity of nine ear cleaners against 50Malassezia pachydermatisisolates
Authors: Mason Carly L. , Steen Stephen I. , Paterson Susan , Cripps Peter J. 
Published: April 2013

BackgroundEar cleaning is an important part of the successful therapy of otitis externa.Hypothesis/ObjectivesTo evaluate thein vitroactivity of nine commercially available ear cleaners (Cerumaural®,CleanAuralDog®,Epi‐Otic®,MalAceticAural®,Otoclean®,Otodine®,Sancerum®,Surosolve®andTrizUltra™ + Keto) against 50Malassezia pachydermatisisolates from clinical cases of canine otitis externa. To the authors' knowledge, this is the first study to analyse thein vitrosusceptibility of a large number ofM. pachydermatisisolates to a variety of ear cleaner products.AnimalsForty‐nine hospital population dogs diagnosed with otitis externa withMalasseziaspp. present on cytological examination of ear swabs and culture.MethodsThe antimicrobial activity of nine ear cleaners was tested against 50M. pachydermatisisolates from 49 clinical cases of canine otitis externa using anin vitroagar diffusion test.ResultsThere were statistically significant differences in activity between ear cleaners, with five showing excellentin vitroanti‐Malasseziaactivity (CleanAuralDog®,Epi‐Otic®,MalAceticAural®,Sancerum®andTrizUltra™ + Keto), two moderate activity (Otodine®andSurosolve®), one variable activity (Otoclean®) and one no activity (Cerumaural®). There was a significant overall difference in susceptibility betweenM. pachydermatisisolates tested (P < 0.001).Conclusions and clinical importanceEar cleaners with activity againstMalasseziamay help to reduce the unnecessary use of antibiotic‐containing polypharmaceutical ear medications. This study shows that the use of a large number of isolates may provide a more accurate account of thein vitroactivity of a product.
Use of Rifamycin Drugs and Development of Infection by Rifamycin-Resistant Strains of Clostridium difficile
Authors: Huang Jamie S. , Jiang Zhi-Dong , Garey Kevin W. , Lasco Todd , DuPont Herbert L. 
Published: April 2013

ABSTRACT

The relationship between rifamycin drug use and the development of resistant strains of
Clostridium difficile
was studied at a large university hospital in Houston, TX, between May 2007 and September 2011. In 49 of 283 (17.3%) patients with
C. difficile
infection (CDI), a rifamycin-resistant strain of
C. difficile
was identified that compares to a rate of 8% using the same definitions in 2006-2007 (
P
= 0.59). The 49 patients infected by a resistant organism were matched by date of admission to 98 control patients with CDI from whom a rifamycin-susceptible
C. difficile
strain was isolated. Cases and controls did not differ according to demographic and clinical characteristics and showed similar but low rates of prior rifamycin use. Similar rates of rifamycin resistance were seen in cases of hospital-acquired CDI (38/112 [34%]) versus community-acquired CDI (7/20 [35%]). At a university hospital in which rifaximin was commonly used, infection by rifamycin-resistant strains of
C. difficile
was not shown to relate to prior use of a rifamycin drug or to acquiring the infection in the hospital, although the rate of overall resistance appeared to be rising.
Human Organic Cation Transporters 1 (
SLC22A1
), 2 (
SLC22A2
), and 3 (
SLC22A3
) as Disposition Pathways for Fluoroquinolone Antimicrobials
Authors: Mulgaonkar Aditi , Venitz Jürgen , Gründemann Dirk , Sweet Douglas H. 
Published: April 2013

ABSTRACT

Fluoroquinolones (FQs) are important antimicrobials that exhibit activity against a wide range of bacterial pathogens and excellent tissue permeation. They exist as charged molecules in biological fluids, and thus, their disposition depends heavily on active transport and facilitative diffusion. A recent review of the clinical literature indicated that tubular secretion and reabsorption are major determinants of their half-life in plasma, efficacy, and drug-drug interactions. In particular, reported
in vivo
interactions between FQs and cationic drugs affecting renal clearance implicated organic cation transporters (OCTs). In this study, 13 FQs, ciprofloxacin, enoxacin, fleroxacin, gatifloxacin, levofloxacin, lomefloxacin, moxifloxacin, norfloxacin, ofloxacin, pefloxacin, prulifloxacin, rufloxacin, and sparfloxacin, were screened for their ability to inhibit transport activity of human OCT1 (hOCT1) (SLC22A1), hOCT2 (SLC22A2), and hOCT3 (SLC22A3). All, with the exception of enoxacin, significantly inhibited hOCT1-mediated uptake under initial test conditions. None of the FQs inhibited hOCT2, and only moxifloxacin inhibited hOCT3 (∼30%), even at a 1,000-fold excess. Gatifloxacin, moxifloxacin, prulifloxacin, and sparfloxacin were determined to be competitive inhibitors of hOCT1. Inhibition constants (

K
i

) were estimated to be 250 ± 18 μM, 161 ± 19 μM, 136 ± 33 μM, and 94 ± 8 μM, respectively. Moxifloxacin competitively inhibited hOCT3-mediated uptake, with a

K
i

value of 1,598 ± 146 μM. Despite expression in enterocytes (luminal), hepatocytes (sinusoidal), and proximal tubule cells (basolateral), hOCT3 does not appear to contribute significantly to FQ disposition. However, hOCT1 in the sinusoidal membrane of hepatocytes, and potentially the basolateral membrane of proximal tubule cells, is likely to play a role in the disposition of these antimicrobial agents.
Evaluation of Ceftaroline Activity against Heteroresistant Vancomycin-Intermediate Staphylococcus aureus and Vancomycin-Intermediate Methicillin-Resistant S. aureus Strains in an
In Vitro
Pharmacokinetic/Pharmacodynamic Model: Exploring the “Seesaw Effect”
Authors: Werth Brian J. , Steed Molly E. , Kaatz Glenn W. , Rybak Michael J. 
Published: April 2013

ABSTRACT

A “seesaw effect” in methicillin-resistant
Staphylococcus aureus
(MRSA) has been demonstrated, whereby susceptibility to β-lactam antimicrobials increases as glyco- and lipopeptide susceptibility decreases. We investigated this effect by evaluating the activity of the anti-MRSA cephalosporin ceftaroline against isogenic pairs of MRSA strains with various susceptibilities to vancomycin in an
in vitro
pharmacokinetic/pharmacodynamic (PK/PD) model. The activities of ceftaroline at 600 mg every 12 h (q12h) (targeted free maximum concentration of drug in serum [
fC
max
], 15.2 μg/ml; half-life [
t
1/2
], 2.3 h) and vancomycin at 1 g q12h (targeted
fC
max
, 18 μg/ml;
t
1/2
, 6 h) were evaluated against 3 pairs of isogenic clinical strains of MRSA that developed increased MICs to vancomycin in patients while on therapy using a two-compartment hollow-fiber PK/PD model with a starting inoculum of ∼10
7
CFU/ml over a 96-h period. Bacterial killing and development of resistance were evaluated. Expression of penicillin-binding proteins (PBPs) 2 and 4 was evaluated by reverse transcription (RT)-PCR. The achieved pharmacokinetic parameters were 98 to 119% of the targeted values. Ceftaroline and vancomycin were bactericidal against 5/6 and 1/6 strains, respectively, at 96 h. Ceftaroline was more active against the mutant strains than the parent strains, with this difference being statistically significant for 2/3 strain pairs at 96 h. The level of PBP2 expression was 4.4× higher in the vancomycin-intermediate
S. aureus
(VISA) strain in 1/3 pairs. The levels of PBP2 and PBP4 expression were otherwise similar between the parent and mutant strains. These data support the seesaw hypothesis that ceftaroline, like traditional β-lactams, is more active against strains that are less susceptible to vancomycin even when the ceftaroline MICs are identical. Further research to explore these unique findings is warranted.
Localization of Phosphatidylinositol 4,5-Bisphosphate to Lipid Rafts and Uroids in the Human Protozoan Parasite Entamoeba histolytica
Authors: Koushik Amrita B. , Powell Rhonda R. , Temesvari Lesly A. 
Published: April 2013

ABSTRACT

Entamoeba histolytica
is an intestinal protozoan parasite and is the causative agent of amoebiasis. During invasive infection, highly motile amoebae destroy the colonic epithelium, enter the blood circulation, and disseminate to other organs such as liver, causing liver abscess. Motility is a key factor in
E. histolytica
pathogenesis, and this process relies on a dynamic actomyosin cytoskeleton. In other systems, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P
2
] is known to regulate a wide variety of cellular functions, including signal transduction, actin remodeling, and cell motility. Little is known about the role of PI(4,5)P
2
in
E. histolytica
pathogenicity. In this study, we demonstrate that PI(4,5)P
2
is localized to cholesterol-rich microdomains, lipid rafts, and the actin-rich fractions of the
E. histolytica
membrane. Microscopy revealed that the trailing edge of polarized trophozoites, uroids, are highly enriched in lipid rafts and their constituent lipid, PI(4,5)P
2
. Polarization and enrichment of uroids and rafts with PI(4,5)P
2
were enhanced upon treatment of
E. histolytica
cells with cholesterol. Exposure to cholesterol also increased intracellular calcium, which is a downstream effector of PI(4,5)P
2
, with a concomitant increase in motility. Together, our data suggest that in
E. histolytica
, PI(4,5)P
2
may signal from lipid rafts and cholesterol may play a role in triggering PI(4,5)P
2
-mediated signaling to enhance the motility of this pathogen.
Toll-Like Receptor 4/Stem Cell Antigen 1 Signaling Promotes Hematopoietic Precursor Cell Commitment to Granulocyte Development during the Granulopoietic Response to Escherichia coli Bacteremia
Authors: Shi Xin , Siggins Robert W. , Stanford William L. , Melvan John N. , Basson Marc D. , Zhang Ping 
Published: April 2013

ABSTRACTIn response to severe bacterial infection, bone marrow hematopoietic activity shifts toward promoting granulopoiesis. The underlying cell signaling mechanisms remain obscure. To study the role of Toll-like receptor 4 (TLR4)/stem cell antigen-1 (Sca-1) signaling in this process, bacteremia was induced in mice by intravenous injection ofEscherichia coli. A subgroup of animals also received intravenous 5-bromo-2-deoxyuridine (BrdU). In a separate set of experiments, bone marrow lineage-negative (lin−) stem cell growth factor receptor-positive (c-kit+) Sca-1−cells containing primarily common myeloid progenitors were culturedin vitrowithout or withE. colilipopolysaccharide (LPS). In genotypic background control mice, bacteremia significantly upregulated Sca-1 expression by lin−c-kit+cells, as reflected by a marked increase in BrdU-negative lin−c-kit+Sca-1+cells in the bone marrow. In mice with the TLR4 gene deletion, this bacteremia-evoked Sca-1 response was blocked.In vitro, LPS induced a dose-dependent increase in Sca-1 expression by cultured marrow lin−c-kit+Sca-1−cells. LPS-induced upregulation of Sca-1 expression was regulated at the transcriptional level. Inhibition of c-Jun N-terminal kinase/stress-activated protein kinase (JNK) activity with the specific inhibitor SP600125 suppressed LPS-induced upregulation of Sca-1 expression by marrow lin−c-kit+Sca-1−cells. Engagement of Sca-1 with anti-Sca-1 antibodies enhanced the expression of Sfpi1 spleen focus-forming virus (SFFV) proviral integration 1 (PU.1) in marrow lin−c-kit+Sca-1−cells cultured with LPS. Sca-1 null mice failed to maintain the marrow pool of granulopoietic cells following bacteremia. These results demonstrate that TLR4/Sca-1 signaling plays an important role in the regulation of hematopoietic precursor cell programming and their enhancement of granulocyte lineage commitment in response toE. colibacteremia.
Sociodemographic Inequalities in Sexual Activity and Cervical Cancer Screening: Implications for the Success of Human Papillomavirus Vaccination
Authors: Drolet Mélanie , Boily Marie-Claude , Greenaway Christina , Deeks Shelley L. , Blanchette Caty , Laprise Jean-François , Brisson Marc 
Published: April 2013

AbstractBackground: Papanicolaou smear screening has significantly reduced cervical cancer morbidity and mortality. However, inequalities still persist across different socioeconomic status (SES) groups. These inequalities have been associated with differential participation in screening. However, even with equal participation to screening, some women may still have greater risk of cervical cancer because of sexual behavior. We aim to identify the sociodemographic characteristics of women who reported greater sexual activity and/or screening underuse.Methods: We used data from (i) the Canadian Community Health Survey—2005, a population-based survey of 130,000 Canadians, and (ii) a multicenter study including 952 women screened for cervical cancer.Results: Aboriginals and women with lower SES reported greater sexual activity and lower screening participation, which may produce synergetic effects toward higher cervical cancer risk. Women who did not complete high school and aboriginals were, respectively, 3.6 and 2.5 times more likely to report sexual debut before 15 years old compared with women with university degree and Caucasians. Women who did not complete high school were 2.2 times more likely to have never been screened compared with women with university degree. East and South Asian women were, respectively, 4.3 and 3.1 times more likely to have never been screened than Canadian-born women but reported lower levels of sexual activity and were adherent to screening guidelines when screened at least once.Conclusions: The success of human papillomavirus vaccination at reducing cervical cancer and inequalities will depend on achieving high coverage among high-risk subpopulations.Impact: These groups must be monitored closely, and if need be, targeted for additional interventions. Cancer Epidemiol Biomarkers Prev; 22(4); 641–52. ©2013 AACR.
Precursors in Cancer Epidemiology: Aligning Definition and Function
Authors: Wacholder Sholom 
Published: April 2013

Abstract
A precursor of a disease is a definable pathologic state that progresses directly to disease without a known intermediate step and whose presence substantially increases the likelihood of disease. Precancers, or precursors of cancer, can help provide detail about the dynamic pathogenesis process before clinical disease. Thereby, ascertainment of properly defined precancers can increase precision of estimates and power in epidemiologic and clinical studies. Besides providing targets for direct treatment and improving tools for risk assessment in screening programs, precancers can help establish temporal ordering of cause and effect; can identify relatively homogeneous subsets of cancer that have passed through a given precancer state; and provide a basis for choosing high-risk individuals for detailed longitudinal study. Although the most appropriate definition of the precancer will vary with its function in particular research or clinical applications, the proportion of cancers that progress from the precancer and risk of cancer progressing from the precancer can be important measures of the value of a precancer in translational efforts. Cancer Epidemiol Biomarkers Prev; 22(4); 521–7. ©2013 AACR.
In School and Out of Trouble? The Minimum Dropout Age and Juvenile Crime
Authors: Anderson D. Mark 
Published: April 2013

AbstractThis paper examines the relationship between the minimum high school dropout age and juvenile arrest rates by exploiting state-level variation in dropout age laws. County-level arrest data for the period 1980 to 2008 and difference-in-difference-in-difference-type empirical strategy are used to compare the arrest rates over time of various age groups within counties that differ by their state's minimum dropout age. The evidence suggests that minimum dropout age requirements have a significant and negative effect on property and violent crime arrest rates for individuals 16 to 18 years old. The results are consistent with an incapacitation effect of schooling.
Monopsony in the Low-Wage Labor Market? Evidence from Minimum Nurse Staffing Regulations
Authors: Matsudaira Jordan D. 
Published: April 2013

Abstract
This paper provides direct evidence on the extent of monopsony power in the low-wage labor market by estimating the firm-level elasticity of labor supply for nurse aides in the long-term care (nursing home) industry. Using exogenous variation in hiring induced by the passage of a state minimum nurse staffing law, I find that facilities initially out of compliance with the new law did not have to raise their wage offers relative to their competitors in order to hire more nurses. While this is consistent with perfect competition in simple monopsony models of the labor market, I discuss how the results may be more ambiguous in more complicated models.
Is the Effect of Competition on Price Dispersion Nonmonotonic? Evidence from the U.S. Airline Industry
Authors: Dai Mian , Liu Qihong , Serfes Konstantinos 
Published: April 2013

Abstract
We investigate the effect of competition on price dispersion in the airline industry. Using panel data from 1993 to 2008, we find a nonmonotonic effect of competition on price dispersion. An increase in competition is associated with greater price dispersion in concentrated markets but with less price dispersion in competitive markets—an inverse-U relationship. Our empirical findings are consistent with an oligopolistic second-degree price discrimination model and encompass contradictory findings in the literature.
Statistical Discrimination or Prejudice? A Large Sample Field Experiment
Authors: Ewens Michael , Tomlin Bryan , Wang Liang Choon 
Published: April 2013

Abstract
A model of racial discrimination provides testable implications for two features of statistical discriminators: differential treatment of signals by race and heterogeneous experience that shapes perception. We construct an experiment in the U.S. rental apartment market that distinguishes statistical discrimination from taste-based discrimination. Responses from over 14,000 rental inquiries with varying applicant quality show that landlords treat identical information from applicants with African American– and white-sounding names differently. This differential treatment varies by neighborhood racial composition and signal type in a manner consistent with statistical discrimination and in contrast to patterns predicted by a model of taste-based discrimination.
Collusion Through Joint R&D: An Empirical Assessment
Authors: Duso Tomaso , Röller Lars-Hendrik , Seldeslachts Jo 
Published: April 2013

Abstract
This paper tests whether upstream R&D cooperation leads to downstream collusion. We show that a sufficient condition for identifying collusive behavior is a decline in the market share of firms participating in research joint ventures (RJVs). Using information from the U.S. National Cooperation Research Act, we estimate a market share equation correcting for the endogeneity of RJV participation and R&D expenditures. We find robust evidence that large networks between direct competitors, created through firms being members in several RJVs at the same time, are conducive to collusive outcomes in the product market that reduce consumer welfare. By contrast, RJVs among noncompetitors are efficiency enhancing.
The Evolution of the Black-White Test Score Gap in Grades K–3: The Fragility of Results
Authors: Bond Timothy N. , Lang Kevin 
Published: April 2013

Abstract
Although both economists and psychometricians typically treat them as interval scales, test scores are reported using ordinal scales. Using the Early Childhood Longitudinal Study (ECLS-K) and the Children of the National Longitudinal Survey of Youth (CNLSY), we examine how order-preserving scale transformations affect the evolution of the black-white reading test score gap from kindergarten entry through third grade. Plausible transformations reverse the growth of the gap in the CNLSY and greatly reduce it in the ECLS-K during the early school years. All growth from entry through first grade and a nontrivial proportion from first to third grade probably reflects scaling decisions.
Credit Spreads as Predictors of Real-Time Economic Activity: A Bayesian Model-Averaging Approach
Authors: Faust Jon , Gilchrist Simon , Wright Jonathan H. , Zakrajšsek Egon 
Published: April 2013

Abstract
Employing a large number of financial indicators, we use Bayesian model averaging (BMA) to forecast real-time measures of economic activity. The indicators include credit spreads based on portfolios, constructed directly from the secondary market prices of outstanding bonds, sorted by maturity and credit risk. Relative to an autoregressive benchmark, BMA yields consistent improvements in the prediction of the cyclically sensitive measures of economic activity at horizons from the current quarter out to four quarters hence. The gains in forecast accuracy are statistically significant and economically important and owe almost exclusively to the inclusion of credit spreads in the set of predictors.