bluuebunny/crossref_metadata_2025 huggingface dataset:
Wenn Kinder nicht mehr leben wollen
Authors: Thielmann Susanna
Published: October 2017

Empfehlungen für die Betreuung Wer Kinder oder Jugendliche nach einem
Suizidversuch betreut, muss neben der somatischen Versorgung auch die
psychosoziale Komponente berücksichtigen. Eine offene und ehrliche Kommunikation
spielt dabei eine entscheidende Rolle.
Notfall Psyche – Diagnostik und Krisenintervention in der Präklinik
Authors: Jordan Wolfgang
Published: October 2017

Der psychiatrische Notfall gehört zu den häufigsten Einsatzursachen für Notärzte. Der Beitrag bietet einen Leitfaden zum Umgang mit Menschen in seelischer Not: von der Orientierung im Notfallgeschehen über eine Zusammenstellung der häufigsten Krankheitsbilder, die Vorstellung spezieller Techniken zur Krisenintervention bis hin zu pharmakologischen Aspekten.
Perspectives on endoscopic surveillance of dysplasia in inflammatory bowel disease: a survey of academic gastroenterologists
Authors: Gallinger Zane , Rumman Amir , Murthy Sanjay , Nguyen Geoffrey
Published: October 2017

Background and study aims Dye-based chromoendoscopy (DBC) is the preferred method for endoscopic dysplasia surveillance in patients with inflammatory bowel disease (IBD). We sought to examine the uptake of, and perception toward DBC among academic gastroenterologists.

Methods We conducted an online survey of academic members of the Canadian Association of Gastroenterology to assess their current dysplasia surveillance practice, uptake of DBC, and perceived barriers to adoption of DBC.

Results Of the 150 physicians contacted, 49 (32.7 %) responded to the survey. The majority of respondents reported subspecialty training in IBD (71.4 %), and the median number of years in practice was 12. White-light endoscopy with random colonic biopsies was the preferred dysplasia screening method (73.5 %). Only 26.5 % of respondents routinely used DBC, despite institutional availability of over 60 %. The major barriers to adoption of DBC were concerns about procedure duration (46.9 %), concerns about cost (44.9 %), and inadequate training (40.8 %).

Conclusion There is low uptake of DBC for dysplasia surveillance in IBD patients among academic gastroenterologists practicing in Canada. Additional studies should be completed to determine how to improve the uptake of DBC.
Links between the charge model and bonded parameter force constants in biomolecular force fields
Authors: Cerutti David S. , Debiec Karl T. , Case David A. , Chong Lillian T.
Published: October 2017

The ff15ipq protein force field is a fixed charge model built by automated tools based on the two charge sets of the implicitly polarized charge method: one set (appropriate for vacuum) for deriving bonded parameters and the other (appropriate for aqueous solution) for running simulations. The duality is intended to treat water-induced electronic polarization with an understanding that fitting data for bonded parameters will come from quantum mechanical calculations in the gas phase. In this study, we compare ff15ipq to two alternatives produced with the same fitting software and a further expanded data set but following more conventional methods for tailoring bonded parameters (harmonic angle terms and torsion potentials) to the charge model. First, ff15ipq-Qsolv derives bonded parameters in the context of the ff15ipq solution phase charge set. Second, ff15ipq-Vac takes ff15ipq’s bonded parameters and runs simulations with the vacuum phase charge set used to derive those parameters. The IPolQ charge model and associated protocol for deriving bonded parameters are shown to be an incremental improvement over protocols that do not account for the material phases of each source of their fitting data. Both force fields incorporating the polarized charge set depict stable globular proteins and have varying degrees of success modeling the metastability of short (5–19 residues) peptides. In this particular case, ff15ipq-Qsolv increases stability in a number of α-helices, correctly obtaining 70% helical character in the K19 system at 275 K and showing appropriately diminishing content up to 325 K, but overestimating the helical fraction of AAQAA3 by 50% or more, forming long-lived α-helices in simulations of a β-hairpin, and increasing the likelihood that the disordered p53 N-terminal peptide will also form a helix. This may indicate a systematic bias imparted by the ff15ipq-Qsolv parameter development strategy, which has the hallmarks of strategies used to develop other popular force fields, and may explain some of the need for manual corrections in this force fields’ evolution. In contrast, ff15ipq-Vac incorrectly depicts globular protein unfolding in numerous systems tested, including Trp cage, villin, lysozyme, and GB3, and does not perform any better than ff15ipq or ff15ipq-Qsolv in tests on short peptides. We analyze the free energy surfaces of individual amino acid dipeptides and the electrostatic potential energy surfaces of each charge model to explain the differences.
Investigation of low temperature quantum crossover in Josephson junctions
Authors: Blackburn James A. , Cirillo Matteo , Grønbech-Jensen Niels
Published: October 2017

The evidence for macroscopic quantum tunneling (MQT) in Josephson junctions at low temperatures has been reassessed. Swept bias escape distributions have been modeled with an algorithm-based simulation and the results compared with data from representative published experiments. Signatures expected of a crossover to MQT are not found in the analyzed data.
Growth mechanisms of multiscale, mound-like surface structures on titanium by femtosecond laser processing
Authors: Peng Edwin , Bell Ryan , Zuhlke Craig A. , Wang Meiyu , Alexander Dennis R. , Gogos George , Shield Jeffrey E.
Published: October 2017

Femtosecond laser surface processing (FLSP) can be used to functionalize many surfaces, imparting specialized properties such as increased broadband optical absorption or super-hydrophobicity/-hydrophilicity. In this study, the subsurface microstructure of a series of mound-like FLSP structures formed on commercially pure titanium using five combinations of laser fluence and cumulative pulse counts was studied. Using a dual beam Scanning Electron Microscope with a Focused Ion Beam, the subsurface microstructure for each FLSP structure type was revealed by cross-sectioning. The microstructure of the mounds formed using the lowest fluence value consists of the original Ti grains. This is evidence that preferential laser ablation is the primary formation mechanism. However, the underlying microstructure of mounds produced using higher fluence values was composed of a distinct smaller-grained α-Ti region adjacent to the original larger Ti grains remaining deeper beneath the surface. This layer was attributed to resolidification of molten Ti from the hydrodynamic Marangoni effect driven fluid flow of molten Ti, which is the result of the femtosecond pulse interaction with the material.
The tuned absorptance in multilayer graphene-dielectric structures by intraband transition
Authors: Yang C. H. , Wang G. X. , Zhang C. , Ao Z. M.
Published: October 2017

In this work, using the transfer-matrix method, the optical transport process is investigated, with graphene inserted into multilayer dielectric structures, theoretically and numerically in the THz regime. When the incident frequency is lower than the graphene Fermi energy, the optical intra-band transitions provide the main contribution to the graphene surface current. The absorptance can be enhanced to about 50% with only one graphene/dielectric layer in air. When increasing the number of dielectric layers coated with graphene, the absorption increases. Periodic absorption peaks are observed in multilayer structures. The positions of the absorption peaks as a function of the frequency and the incident angle are in accordance with the positions of the abrupt change in the reflection coefficient phase and of the imaginary solution of the Bloch wavevector in expanding periodic structures using Bloch theorem.
The effect of density-of-state tails on band-to-band tunneling: Theory and application to tunnel field effect transistors
Authors: Sant S. , Schenk A.
Published: October 2017

It is demonstrated how band tail states in the semiconductor influence the performance of a Tunnel Field Effect Transistor (TFET). As a consequence of the smoothened density of states (DOS) around the band edges, the energetic overlap of conduction and valence band states occurs gradually at the onset of band-to-band tunneling (BTBT), thus degrading the sub-threshold swing (SS) of the TFET. The effect of the band tail states on the current-voltage characteristics is modelled quantum-mechanically based on the idea of zero-phonon trap-assisted tunneling between band and tail states. The latter are assumed to arise from a 3-dimensional pseudo-delta potential proposed by Vinogradov [1]. This model potential allows the derivation of analytical expressions for the generation rate covering the whole range from very strong to very weak localization of the tail states. Comparison with direct BTBT in the one-band effective mass approximation reveals the essential features of tail-to-band tunneling. Furthermore, an analytical solution for the problem of tunneling from continuum states of the disturbed DOS to states in the opposite band is found, and the differences to direct BTBT are worked out. Based on the analytical expressions, a semi-classical model is implemented in a commercial device simulator which involves numerical integration along the tunnel paths. The impact of the tail states on the device performance is analyzed for a nanowire Gate-All-Around TFET. The simulations show that tail states notably impact the transfer characteristics of a TFET. It is found that exponentially decaying band tails result in a stronger degradation of the SS than tail states with a Gaussian decay of their density. The developed model allows more realistic simulations of TFETs including their non-idealities.
Three-level cobblestone-like TiO2 micro/nanocones for dual-responsive water/oil reversible wetting without fluorination
Authors: Zhou Chen , Li Guoqiang , Li Chuanzong , Zhang Zhen , Zhang Yachao , Wu Sizhu , Hu Yanlei , Zhu Wulin , Li Jiawen , Chu Jiaru , Hu Zhijia , Wu Dong , Yu Liandong
Published: October 2017

In this work, a kind of three-level cobblestone-like anatase TiO2 microcone array was fabricated on titanium sheets by femtosecond laser-induced self-assembly. This three level structure consisted of cobblestone-like features (15–25 μm in height and 20–35 μm in diameter), ∼460 nm ripple-like features, and smaller particles (10–500 nm). The formation of microcone arrays can be ascribed to the interaction of alternant laser beam ablation. TiO2 surfaces display dual-responsive water/oil reversible wetting via heat treatment and selective UV irradiation without fluorination. It is indicated that three-level scale surface roughness can amplify the wetting character of the Ti surface, and the mechanism for reversible switching between extreme wettabilities is caused by the conversion between Ti-OH and Ti-O. Moreover, the double-faced superhydrophobic and double-faced superhydrophilic Ti samples were constructed, which exhibited stable superhydrophobicity and underwater superoleophobicity in water-oil solution, respectively, even when strongly shaken. Finally, we present the hybrid-patterned TiO2 surface and realized reversible switching pattern wettability.
Enhanced spin-dependent charge transport of Co-(Al-fluoride) granular nanocomposite by co-separate sputtering
Authors: Cao Yang , Kobayashi Nobukiyo , Zhang Yi-Wen , Ohnuma Shigehiro , Masumoto Hiroshi
Published: October 2017

Spin-dependent charge transport behavior involving the recently discovered tunnel-type magneto-dielectric (TMD) and magnetoresistance (TMR) effects was studied in Co-(Al-fluoride) granular nanocomposites. By setting a changeable partition height (t = 1–4 cm) on a substrate holder in a conventional co-sputtering (CS) deposition system, we developed a co-separate sputtering (CSS) method to fabricate Co-(Al-F) granular nanocomposites. XPS analysis shows that the Al content remains balanced between the Al metal and Al-F compounds by controlling t. This phenomenon can be attributed to the magnetron plasma interference from the two target sources. Fittings between TMR and normalized magnetization suggest that the CSS films with clear granular structures may have high spin polarization. Compared with the CS samples (t = 0 cm), the CSS films with t = 4 cm show enhanced charge transport properties with a maximum TMD ratio (0.5%) and TMR ratio (7.2%) under a magnetic field of H = 10 kOe. This study demonstrates that the Al-F tunnel barrier between Co granules plays an essential role in controlling the charge transport behavior and will be of significance for applications in field sensors and impedance-tunable devices with large magnetic-field response.
The non-linear terahertz response of hot electrons in low-dimensional semiconductor superlattices: Suppression of the polar-optical phonon scattering
Authors: Ignatov Anatoly A.
Published: October 2017

We study the response of low-dimensional semiconductor superlattices to strong terahertz fields on condition of a strong suppression of inelastic scattering processes of electrons caused by the polar-optical phonons. For our study, we employ a balance equations approach, which allows investigating the response of the superlattices to strong terahertz fields taking account of both the inelastic and the strongly pronounced elastic scattering of electrons. Our approach provides a way to analyze the influence of the Bloch dynamics of electrons in a superlattice miniband side by side with the effects of the electron heating on the magnitude and the frequency dependence of a superlattice current responsivity in the terahertz frequency band. Our study shows that the suppression of the inelastic scattering caused either by a reduction of the superlattice dimensionality by lateral quantization or by a strong magnetic field application can give rise to a huge enhancement of the current responsivity. This enhancement can be interpreted in terms of the well pronounced electronic bolometric effect occurring due to the efficient electron heating in the low-dimensional superlattices by the incident terahertz fields.
On Parfit’s Ontology
Authors: Mintz-Woo Kian
Published: October 2017

Parfit denies that the introduction of reasons into our ontology is costly for his theory. He puts forth two positions to help establish the claim: the Plural Senses View and the Argument from Empty Ontology. I argue that, first, the Plural Senses View for ‘exists’ can be expanded to allow for senses which undermine his ontological claims; second, the Argument from Empty Ontology can be debunked by Platonists. Furthermore, it is difficult to make statements about reasons true unless these statements include reference to objects in reality. These arguments show the instability of Parfit’s claimed metaethical advantages over naturalism.
On the local Langlands correspondence and Arthur conjecture for even orthogonal groups
Authors: Atobe Hiraku , Gan Wee
Published: October 2017

In this paper, we highlight and state precisely the local Langlands correspondence for quasi-split

O

2
n

\mathrm {O}_{2n}

established by Arthur. We give two applications: Prasad’s conjecture and Gross–Prasad conjecture for

O

n

\mathrm {O}_n

. Also, we discuss the Arthur conjecture for

O

2
n

\mathrm {O}_{2n}

, and establish the Arthur multiplicity formula for

O

2
n

\mathrm {O}_{2n}

.
A note on higher extremal metrics
Authors: Pingali Vamsi
Published: October 2017

In this paper we introduce “higher extremal Kähler” metrics. We provide an example of the same on a minimal ruled surface. We also prove a perturbation result that implies that there are non-trivial examples of “higher constant scalar curvature” metrics, which are basically metrics where the top Chern form is harmonic. We also give a relatively short proof of Liu’s formula for the Bando-Futaki invariants (which are obstructions for the existence of harmonic Chern forms) of hypersurfaces of projective space.
diffuStats: an R package to compute diffusion-based scores on biological networks
Authors: Picart-Armada Sergio , Thompson Wesley K , Buil Alfonso , Perera-Lluna Alexandre
Published: October 2017

Label propagation and diffusion over biological networks are a common mathematical formalism in computational biology for giving context to molecular entities and prioritizing novel candidates in the area of study. There are several choices in conceiving the diffusion process—involving the graph kernel, the score definitions and the presence of a posterior statistical normalization—which have an impact on the results. This manuscript describes diffuStats, an R package that provides a collection of graph kernels and diffusion scores, as well as a parallel permutation analysis for the normalized scores, that eases the computation of the scores and their benchmarking for an optimal choice.

Availability and implementation

The R package diffuStats is publicly available in Bioconductor, https://bioconductor.org, under the GPL-3 license.

Supplementary information

Supplementary data are available at Bioinformatics online.
Deficit in PINK1/PARKIN-mediated mitochondrial autophagy at late stages of dystrophic cardiomyopathy
Authors: Kang Chifei , Badr Myriam A , Kyrychenko Viktoriia , Eskelinen Eeva-Liisa , Shirokova Natalia
Published: October 2017

Aims

Duchenne muscular dystrophy (DMD) is an inherited devastating muscle disease with severe and often lethal cardiac complications. Emerging evidence suggests that the evolution of the pathology in DMD is accompanied by the accumulation of mitochondria with defective structure and function. Here, we investigate whether defects in the housekeeping autophagic pathway contribute to mitochondrial and metabolic dysfunctions in dystrophic cardiomyopathy.

Methods and results

We employed various biochemical and imaging techniques to assess mitochondrial structure and function as well as to evaluate autophagy, and specific mitochondrial autophagy (mitophagy), in hearts of mdx mice, an animal model of DMD. Our results indicate substantial structural damage of mitochondria and a significant decrease in ATP production in hearts of mdx animals, which developed cardiomyopathy. In these hearts, we also detected enhanced autophagy but paradoxically, mitophagy appeared to be suppressed. In addition, we found decreased levels of several proteins involved in the PINK1/PARKIN mitophagy pathway as well as an insignificant amount of PARKIN protein phosphorylation at the S65 residue upon induction of mitophagy.

Conclusions

Our results suggest faulty mitophagy in dystrophic hearts due to defects in the PINK1/PARKIN pathway.
The gas and stellar mass of low-redshift damped Lyman-α absorbers
Authors: Kanekar Nissim , Neeleman Marcel , Prochaska J Xavier , Ghosh Tapasi
Published: October 2017

We report Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet and Arecibo Telescope H i 21 cm spectroscopy of six damped and sub-damped Lyman-α absorbers (DLAs and sub-DLAs, respectively) at z ≲ 0.1, which have yielded estimates of their H i column density, metallicity and atomic gas mass. This significantly increases the number of DLAs with gas mass estimates, allowing the first comparison between the gas masses of DLAs and local galaxies. Including three absorbers from the literature, we obtain H i masses ≈(0.24–5.2) × 109 M⊙, lower than the knee of the local H i mass function. This implies that massive galaxies do not dominate the absorption cross-section for low-z DLAs. We use Sloan Digital Sky Survey photometry and spectroscopy to identify the likely hosts of four absorbers, obtaining low stellar masses, ≈107–108.4 M⊙, in all cases, consistent with the hosts being dwarf galaxies. We obtain high H i 21 cm or CO emission line widths, ΔV20 ≈ 100–290 km s−1, and high gas fractions, fH i ≈ 5–100, suggesting that the absorber hosts are gas-rich galaxies with low star formation efficiencies. However, the H i 21 cm velocity spreads (≳100 km s−1) appear systematically larger than the velocity spreads in typical dwarf galaxies.
Antibiotic Prescribing for Dental Procedures in Community-Associated Clostridium difficile cases, Minnesota, 2009–2015
Authors: Bye Maria , Whitten Tory , Holzbauer Stacy
Published: October 2017

Background

Clostridium difficile infections (CDIs) are the leading cause of healthcare-associated diarrhea. Two of the most significant risk factors for CDI are antibiotic use and healthcare exposure. Dentists write approximately 10% of all outpatient prescriptions in the USA; however, limited data are available regarding dental prescribing’s impact on CDI. We described characteristics of community-associated (CA) CDI cases following antibiotics for dental procedures.

Methods

The Minnesota Department of Health (MDH) performs active population- and laboratory-based surveillance for CDI as part of the CDC’s Emerging Infections Program (EIP). A case was defined as a positive C. difficile toxin or molecular assay on a stool specimen from a person >1 years old without a positive test in the prior 8 weeks, living in one of the five EIP catchment counties. Cases were classified as CA if stool was collected ≤3 days of admission or as an outpatient, with no overnight stay in a healthcare facility in the past 12 weeks. Medical records were reviewed and interviews performed to assess CDI risk factors and potential exposures. Differences in antibiotic prescribing and documentation among CA CDI cases receiving dental procedures were explored.

Results

During 2009–2015, 2176 presumptive CA CDI cases were reported to MDH; 1626 (75%) were confirmed as CA and interviewed. In total, 926 (57%) were prescribed antibiotics and 136 (15%) for dental procedures. Cases prescribed antibiotics for dental procedures were significantly older (median age: 57 vs. 45 years, P < 0.001), more likely to be prescribed clindamycin (50% vs. 10%, P < 0.001), and less likely to be prescribed fluoroquinolones (6% vs. 19%, P < 0.001) and cephalosporins (7% vs. 30%, P < 0.001) than those prescribed antibiotics for other indications. Among cases who received antibiotics for a dental procedure, 31 (23%) reported antibiotics on interview which were also documented in the medical record and 46 (34%) reported antibiotics for any reason on interview without documentation in the medical record.

Conclusion

Dental antibiotic prescribing rates are likely underestimated. Stewardship programs should address dental prescribing and alert dentists to CDI subsequent to antibiotics prescribed for dental procedures.

Disclosures

All authors: No reported disclosures.
Etiology of Infectious Diarrhea in Patients Tested for Clostridium difficile: If It Isn’t Clostridium difficile, What Is It?
Authors: Kwon Jennie H , Hink Tiffany , Reske Kimberly , Dubberke Erik R , Burnham Carey-Ann D
Published: October 2017

Background

The objective of the study was to assay for alternative infectious causes of diarrhea in patients with negative EIA tests for Clostridium difficile.

Methods

A hard-stop alert was implemented at a tertiary care hospital to limit repeat testing for C. difficile within 96 hours of an initial negative EIA. Stool samples from patients with a negative (–) repeat EIA test for C. difficile within 96 hours in the 3 months pre- and postintervention underwent further evaluation: C. difficile toxigenic culture, GeneXpert C. difficile PCR, Biofire Gastrointestinal (GI) Panel, and culture on a blood agar plate.

Results

Of the 84 C. difficile EIA stool specimens evaluated, 8% were toxigenic culture positive (+), 8% tested + for C. difficile via the Biofire GI panel, and 5 (7%) + with the GenXpert C. difficile PCR (Table 1). Three of these patients were diagnosed with CDI within 30 days of a + test. Five patients were + for Norovirus via Biofire GI panel; none were tested for or diagnosed with Norovirus. Two patients were + for Enteropathogenic E. coli and one for Enteroaggregative E. coli via Biofire GI panel; none were tested for or diagnosed with E. coli infection. One patient was positive for Salmonella and Salmonella was isolated by stool culture.

Conclusion

Patients tested for C. difficile may have alternate causes of diarrhea. When evaluating hospitalized patients with diarrhea, C. difficile, along with alternate causes of diarrhea can be considered.

Disclosures

E. R. Dubberke, Merck: Consultant, Consulting fee; Biofire: one time talk, Speaker honorarium;; Alere: one-time talk, Speaker honorarium; Sanofi pasteur: Grant Investigator, Grant recipient; Pfizer: Consultant, Consulting fee; Rebiotix: Investigator, Research support; Rebiotix: Consultant, Consulting fee; valneva: Consultant, Consulting fee; C. A. D. Burnham, bioMerieux: Grant Investigator, Research grant; ThermoFisher: Consultant, Salary; Cepheid: Grant Investigator, Research grant
Risk Factors for Early Hip or Knee Prosthetic Joint Infection (PJI): Analysis of a Nationwide American Insurance Claims Dataset
Authors: Tande Aaron , Asante Dennis , Sangaralingham Lindsey , Osmon Douglas , Heien Herbert , Mabry Tad , Berbari Elie F
Published: October 2017

Background

While several studies have identified risk factors for PJI using insurance claims data, these data sets have been limited to a single regional insurance dataset or to the Medicare population. We sought to investigate risk factors for early PJI among patients undergoing total hip or knee arthroplasty (THKA).

Methods

All patients who underwent primary THKA between January 1, 2004 and July 31, 2014 with 12 months of continuous preceding medical and pharmacy insurance coverage were included in the study. The primary outcome of PJI required both a compatible procedure code and a diagnostic code during an inpatient stay from the time of THKA through 90 days after discharge. Comorbidities were based on ICD-9 codes in the preceding 12 months and patients with a prior diagnosis of PJI during that time period were excluded. Univariate and multivariate analysis was performed using logistic regression.

Results

A total of 147,053 patients underwent THKA during the study period, including 97,448 patients with TKA and 49,605 with THA. PJI occurred in 754 (0.5%) patients. Female gender was independently associated with lower odds of PJI (Figure). A number of biologically plausible factors were associated with increased risk, including chronic skin ulcer, obesity, substance use disorders, joint sarcoma, and malnutrition. The adjusted odds of PJI increased in a stepwise fashion with each increase in the Charlson comorbidity index (CCI), with those with a score of 4 or more having a nearly 2-fold adjusted odds of PJI compared with a score of 0 (OR 1.91; 95% CI 1.29 −2.82). Previously observed risk factors diabetes mellitus, rheumatoid arthritis, and chronic renal failure were associated with increased odds of PJI on univariate analysis, but not after adjustment.

Conclusion

These data identify several potentially modifiable risk factors for preoperative optimization, including obesity, malnutrition, chronic skin ulcers, and substance-use disorders. The level of comorbidity as assessed by the CCI provides a rough estimate of the increasing risk of PJI. The pathobiology of additional risk factors observed here deserves further study.

Disclosures

All authors: No reported disclosures.
Increasing Kingella Identification in Bone and Joint Infections in Young Children
Authors: Quick Rachel , Williams John , Cosgrove Peter , Kahlden Kyle , Fernandez Marisol , Thoreson Lynn , Hauger Sarmistha
Published: October 2017

Background

Kingella kingae is an increasingly recognized pathogen among young children with bone and joint infections. Antibiotics given to cover methicillin-resistant Staphylococcus aureus are not effective against Kingella, and necessitate additional empiric antibiotics in this age group. Improving Kingella identification can narrow antibiotic choices and improve efficacy for long-term oral therapy.

Methods

We implemented a bone and joint infection guideline at a free standing children’s hospital that called for early imaging, focal sampling, and polymerase chain reaction (PCR) testing for culture-negative specimens. The goal was to increase identification of Kingella and other pathogens to improve targeted antimicrobial therapy. Children 6 to ≤ 60 months of age with uncomplicated acute hematogenous osteomyelitis or septic arthritis between January 1, 2009–December 31, 2016, were included in this study. Outcomes of bacterial identification were measured.

Results

Charts for 49 cases that met criteria were reviewed. Prior to the algorithm, we identified Kingella in 4% (1/25) of cases. Following routine use of updated sampling and testing techniques, including PCR testing, Kingella kingae identification increased to 29% of cases (7/24; P = 0.02) and, in fact, was the predominant pathogen identified in this age group.

Conclusion

Identification of Kingella was enhanced as a result of changes to sampling and testing, including PCR testing (Figure 1). Post-implementation, Kingella was more commonly identified than Staphylococcus aureus. Widespread availability of PCR testing in the future may allow for the use of narrowed antibiotic therapy and targeted transition to oral antibiotics in young children with bone or joint infection.

Disclosures

All authors: No reported disclosures.
Concordance of Results of Blood and Tissue Cultures from Patients with Pyogenic Spondylitis
Authors: Bae Ji Yun , Kim Chung-Jong , Kim Uh Jin , Song Kyoung-Ho , Kim Eu Suk , Kang Seung Ji , Oh Myoung-Don , Park Kyung-Hwa , Kim Nam Joong
Published: October 2017

Background

The aim of this study was to investigate the concordance of results of blood and tissue cultures in patients with pyogenic spondylitis.

Methods

We searched the patients with pyogenic spondylitis in whom micro-organisms were isolated from both blood and tissue cultures by retrospective review of medical records in three tertiary university-affiliated hospitals between January 2005 and December 2015. The species and antimicrobial susceptibility patterns of isolates from blood and tissue cultures were compared with each other.

Results

Among 141 patients with pyogenic spondylitis in whom micro-organisms were isolated from both blood and tissue cultures, the species of blood and tissue isolates were identical in 135 patients (95.7%, 135/141). Excluding the four anaerobic isolates, we investigated antimicrobial susceptibility patterns of 131 isolates of same species from blood and tissue cultures. Antibiotic susceptibility patterns were identical in 128 patients (97.7%, 128/131). The most common isolates were Staphylococcus aureus (86 patients; 85 concordant and 1 discordant), followed by streptococcus (24 patients; 22 concordant and 2 discordant), and Escherichia coli (8 patients; all concordant).

Conclusion

We suggest that a positive blood culture from patients with pyogenic spondylitis could preclude the need for additional tissue cultures, especially when S. aureus and streptococcus grew in blood cultures.

Disclosures

All authors: No reported disclosures.
Does Detection of Respiratory Viral Infection in Upper Respiratory Tract (URT) Predict Lower Respiratory Tract (LRT) Disease in Hematopoietic Cell Transplant (HCT) Patients?
Authors: Vivek Meghana , Xie Hu , Pergam Steven A , Mielcarek Marco , Hill Joshua , Kuypers Jane , Jerome Keith , Limaye Ajit , Leisenring Wendy , Boeckh Michael , Waghmare Alpana
Published: October 2017

Background

HCT recipients are frequently infected with respiratory viruses (RVs) in the URT; however, diagnostic evaluation of the LRT by bronchoalveolar lavage (BAL) is less common. We sought to determine whether the detection of RVs in the URT is predictive of LRT detection and to identify factors that predict discordance between upper and lower RV detection.

Methods

HCT recipients with respiratory symptoms and LRT RV testing via multiplex PCR in BAL from July 2009 to October 2016 were included in the study. RV PCR results, including cycle threshold (CT) values, were compared with URT samples obtained within ±3 days. Logistic regression models were used to analyze risk factors for RV discordance between paired samples.

Results

Among 1,000 HCT recipients with BAL RV testing, 250 had URT testing within 3 days. In total, 75(30%) sample pairs were concordant for the same RV in both the URT and BAL (P/P); 132 (53%) were negative from both sites. Among 43 discordant pairs, 25 (10%) were only positive by URT but negative by BAL (P/N) and 18 (7%) were positive by BAL but negative by URT (N/P). In pairs with positive RV results in the URT or BAL, discordance was common for HMPV (44%), HRV (33%), and PIV-3 (28%); RSV was almost always concordant (92%) (Figure 1). In a multivariable model, the risk of discordance (P/N or N/P) was increased in the presence of a solitary nodule on radiography (OR 6.8; 95% CI 1.2–38.3) and with lymphocyte count >500/mm3 (OR 3.1; 95% CI 1.08–9.0). Among P/P pairs, the median difference between CT values between URT and BAL samples was 0 (range −12 to +13), with 33 and 29% of subjects having lower and higher CT values (>4, ~1 log10) in the BAL, respectively (Figure 2).

Conclusion

In symptomatic HCT recipients with RV PCR testing performed concurrently in the upper and lower tract, discordant results are relatively common, especially for HRV, HMPV, and PIV-3. The presence of a solitary nodule on imaging and the absence of lymphopenia are associated with discordant results, with BAL results more likely being negative in these situations. More than half of the P/P pairs had a >4 difference in CT values between URT and LRT samples. Taken together, these data suggest that RV testing in BAL can provide useful diagnostic information that may guide management in HCT recipients.

Disclosure

S. A. Pergam, MERCK: Consultant and Investigator, Consulting fee.
Solid Organ Transplantation (SOT) and Data Mining: Bloodstream Infections (BSI) Have a Significant Impact on One-Year Survival, and qSOFA ≥ 2 Predicts 30-Day Mortality
Authors: Liu Terrence , Xie Donglu , Adams-Huet Beverley , Le Jade , Yek Christina , Ranganathan Dipti , Haley Robert W , Greenberg David , Hoz Ricardo La
Published: October 2017

Background

We created a retrospective and prospective database of SOT recipients using innovative data mining tools. This study describing the epidemiology of BSI in SOT serves as a proof of concept of such techniques in clinical research.

Methods

The design of the study was a retrospective, single-center, cohort study. Data mining tools were used to extract information from the electronic medical record and merged it with data from the SRTR (Figure 1). First SOT from January 1, 2010 to December 31, 2015 were included. Charts of subjects with positive blood cultures were manually reviewed and adjudicated using CDC/NHSN and SCCM/ESICM criteria. The 1-year cumulative incidence was calculated using the Kaplan–Meier method. Cox proportional hazards models were used to identify risk factors for BSI and 1-year mortality. BSI was analyzed as a time-dependent covariate in the mortality model. Fisher’s exact test and chi-square were used to identify risk factors for 30-day mortality and MDRO.

Results

A total of 917 SOT recipients met inclusion criteria. Seventy-five patients experienced at least one BSI. The cumulative incidence was 8.4% (95% CI 6.8–10.4) (Figure 2). The onset of the first BSI episode was: 30 episodes (40%) <1 month, 33 (44%) 1–6 months, and 12 (16%) >6 months. The most common pathogens were Klebsiella sp. (16%), Vancomycin-resistant E. faecium (12%), E. coli (12%), CoNS (12%), and Candida sp. (9.3%). Nineteen isolates (25%) were identified as MDRO; the risk of MDRO was highest <1 month compared with 1–6 and >6 months (44.8 vs. 12.1 vs. 16.7; P = 0.01). The most common source of BSI was CLABSI (29%) (Figure 3). In multivariable analysis, the risk of BSI was associated with organ type (HR [95% CI] = Multiorgan 3.5 [1.1–11.6], liver 2.5 [1.1–5.4], heart 2.4 [1.1–5.1]) and acquisition of a BSI was associated with a higher 1-year mortality (HR = 8.7 [5.1–14.7]). In univariable analysis, a polymicrobial BSI (14.7 vs. 57.1%; P = 0.02), qSOFA ≥ 2 (0.0 vs. 25.5%; P = 0.02) and septic shock (3.9 vs. 52.2%; P < 0.001) were associated with an increased risk of death at 30 days.

Conclusion

A BSI significantly affects the 1-year survival of SOT recipients. A qSOFA ≥ 2 can be used to identify patients at risk for death. Additionally, this study illustrates the potential of data mining tools to study infectious complications.

Disclosures

All authors: No reported disclosures.
Investigation of a Contaminated, Nationally Distributed, Organ Transplant Preservation Solution — United States, 2016–2017
Authors: Stuckey Matthew , Novosad Shannon , Wilde Nancy , Annambhotla Pallavi , Basavaraju Sridhar , Moulton-Meissner Heather , Seiber Kathy , Perz Joseph , Quinlisk Patricia , Garvey Ann , Conrad Suzanne , Fewell Sarah , Hill Sam , Edmond Michael , Diekema Daniel , Ford Bradley , Reed Alan , Benowitz Isaac , Walters Maroya Spalding
Published: October 2017

Background

In December 2016, bacterial contamination of an organ preservation solution (OPS) was reported by Transplant Center A in Iowa. Annually, >20,000 abdominal organs are transplanted in the United States; OPS is used for organ storage. We investigated the scope of OPS contamination and its association with adverse events in patients.

Methods

We assessed infection control practices related to OPS at Transplant Centers A and B in Iowa and the local organ procurement organization (OPO). We issued national notifications about OPS contamination and requested transplant centers to report product-related concerns or potential patient harm. Among transplant recipients at Center A, we compared adverse events (fever, bacteremia, surgical site infection, peritonitis, or pyelonephritis within 14 days of transplantation) during October–December 2015 with October–December 2016, the presumed window of exposure to contaminated OPS. Isolates from OPS were characterized.

Results

No infection control deficiencies were identified at Transplant Centers A, B, or the OPO. In January 2017, contaminated OPS from the same manufacturer was reported by Transplant Center C in Texas. Nationally, there were no reports of patient harm definitively linked to OPS. Post-transplant adverse events at Center A did not increase between fourth quarter 2015 (5/12 [42%]) and 2016 (2/15 [13%]). Organisms recovered from OPS included Pantoea agglomerans and Enterococcus gallinarum (Center A) and Pseudomonas koreensis (Center C). Five Pantoea isolates from ≥3 opened OPS bags were indistinguishable by pulsed-field gel electrophoresis. The OPS distributor issued recalls and suspended production. The US Food and Drug Administration identified deficiencies in current good manufacturing practices at manufacturing and distribution facilities, including inadequate validation of OPS sterility.

Conclusion

Bacterial contamination of a nationally distributed product was identified by astute clinicians. The investigation found no illnesses were directly linked to the product. Prompt reporting of concerns about potentially contaminated healthcare products, which might put patients at risk, is critical for swift public health action.

Disclosures

All authors: No reported disclosures.
Cefazolin plus Clavulanic Acid Overcomes the Inoculum Effect in a Methicillin-Susceptible Staphylococcus aureus (MSSA) Rat Endocarditis Model
Authors: Miller William , Singh Kavindra , Arias Cesar , Murray Barbara
Published: October 2017

Background

The inoculum effect (InE) refers to an increase in the MIC of an antibiotic when a large burden of bacteria is present. MSSA producing type A or C β-lactamase (β-lac) that display this effect may be at risk of clinical failure when treated with cefazolin (CFZ) for a deep-seated infection. We have previously shown that CFZ plus clavulanic acid (CL) abolished the InE in vitro. The aim of this study was to evaluate the effectiveness of the combination in vivo at clinically achievable concentrations of both CFZ and CL.

Methods

S. aureus TX0117, a type A Bla+ clinical isolate from a patient who failed CFZ therapy and TX0117-cured (TX0117c), a derivative of TX0117 which lacks β-lac activity, were used in a rat model of endocarditis. One animal per strain, in addition to historical controls (n = 22), was sacrificed at the start of therapy to assess colony forming units (CFU) per gram of vegetation at T = 0. CFZ 50mg/kg alone (n = 11) or CFZ 50mg/kg plus CL 4mg/kg (n = 7) was given IM every 8 hours for 72 hours. Doses were selected to mimic mean serum concentration of standard doses (given IM (CFZ) or PO (CL)) in humans. Rats were sacrificed 16 hours after the last antibiotic dose, aortic valves were aseptically excised, weighed, homogenized in 1ml of saline and the entire volume was plated in serial 10-fold dilutions on mannitol salt and/or brain-heart infusion agar. Representative recovered colonies were tested for β-lac activity using nitrocefin. Comparisons of CFU between groups were done by the Mann–Whitney, Wilcoxon unpaired test with significance at p < 0.05.

Results

At baseline, there was no significant difference between the CFU/g of control animals infected with the two strains (TX0117 7.3±1.3 and TX0117c 7.89±0.83, mean log10 ± SD). Compared with untreated controls, the TX0117 group treated with CFZ alone had a reduction of 2±0.6 CFU/g, while the CFZ plus CL arm had a 7.1±0.5 CFU/g reduction, a statistically significant difference between the two arms (P = 0.0002). CFZ treatment of the TX0117c strain lacking blaZ activity was similar to CFZ+CL (6.5±0.6 log10 CFU/g reduction, P < 0.0001).

Conclusion

Against Bla+ TX0117, the addition of CL, at a dose mimicking human PO kinetics, restored the efficacy of CFZ and overcame the InE. This provides a proof-of-concept for the use of oral CL with CFZ when there is a concern for the InE.

Disclosures

All authors: No reported disclosures.
Characterization of New HIV Infections among Adults ≥45 Years—New York City, North Carolina, San Francisco, 2011–2013
Authors: Evans Mary , Patala Anne , Campbell Ellsworth , Westheimer Emily , Gay Cynthia L , Cohen Stephanie E , Switzer William M , Peters Philip J
Published: October 2017

Background

While HIV prevention activities are often focused on younger people, older people can also be at risk for HIV infection. We aimed to characterize HIV transmission in older adults.

Methods

The STOP study was a multi-site prospective study of persons with acute HIV infection (AHI) from 2011 to 2013. Older adults were defined as ≥45 years and younger persons were 13–44 years. AHI was defined by a negative rapid test but a reactive antigen/antibody or HIV RNA test. We performed bivariate analysis using Pearson’s chi-square and odds ratios to examine associations between older age and transmission characteristics. Among persons with HIV-1 polymerase (pol) sequences, transmission linkages were inferred when the genetic distance between sequences was <1.5% and did not indicate directionality of transmission.

Results

Among 86,836 participants (median age, 29 years; 75.0% male; 51.8% MSM), HIV infection was diagnosed in 176 (1.46%) of 12,036 older adults compared with 1,150 (1.53%) of 74,800 younger people (P = 0.56). Among HIV-infected persons, AHI was diagnosed in similar proportions of older and younger people (13.1% vs. 12.6%; P = 0.86). Among HIV-infected persons who participated in partner notification (n = 1,326), older adults were less likely to report meeting a sex partner online (11.3% vs. 26.9%; OR 0.52, 95% CI = 0.35–0.78) and were less likely to name ≥2 sex partners (31.5% vs. 46.8%; OR = 0.28, 95% CI = 0.15–0.53) compared with younger people. Among HIV-infected persons with HIV-1 pol sequences (n = 537), similar proportions of older and younger people had viruses that genetically linked with another study participant (15.9% vs. 23.5%; OR 0.62, 95% CI 0.31–1.22) (Figure).

Conclusion

In this study, older adults had a similar frequency of newly diagnosed HIV infection, acute infection, and genetic linkage compared with younger people, suggesting that increased HIV prevention efforts may be needed in this population.

Disclosures

All authors: No reported disclosures.
Impact of Procalcitonin Guidance on the Management of Adults Hospitalized with Pneumonia
Authors: Walsh Thomas , DiSilvio Briana , Hammer Crystal , Beg Moeezullah , Vishwanathan Swati , Speredelozzi Daniel , Moffa Matthew , Hu Kurt , Abdulmassih Rasha , Makadia Jina , Sandhu Rikinder , Naddour Mouhib , Chan-Tompkins Noreen , Trienski Tamara , Watson Courtney , Bremmer Derek
Published: October 2017

Background

Community-acquired pneumonia and healthcare-associated pneumonia are often treated with prolonged antibiotic therapy. Procalcitonin (PCT) has effectively and safely reduced antibiotic use for pneumonia in controlled studies. However, limited data exist regarding PCT guidance in real-world settings for management of pneumonia.

Methods

A retrospective, preintervention/postintervention quality improvement study was conducted to compare management for patients admitted with pneumonia before and after implementation of PCT guidance at two teaching hospitals in Pittsburgh, Pennsylvania. The preintervention period was March 1, 2014 through October 31, 2014, and the post-intervention period was March, 1 2015 through October 31, 2015.

Results

A total of 152 and 232 patients were included in the preintervention and postintervention cohorts, respectively. When compared with the preintervention group, the mean duration of therapy decreased (9.9 vs. 6.1 days; P < 0.001). More patients received an appropriate duration of 7 days or less (26.9% vs. 66.4%; P < 0.001). Additionally, mean hospital length of stay decreased in the postintervention group (4.9 vs. 3.5 days; P = 0.006). Pneumonia-related 30-day readmission rates (7.2% vs. 4.3%; P = 0.99) were unaffected. In the postintervention group, patients with PCT levels < 0.25 µg/l received shorter mean duration of therapy compared with patients with levels >0.25 µg/l (8.0 vs. 4.6 days; P < 0.001) as well as reduced hospital length of stay (3.9 vs. 3.2 days; P = 0.02).

Conclusion

In this real-world practice study, PCT guidance led to shorter durations of total antibiotic therapy and abridged inpatient length of stay without affecting hospital re-admissions.

Disclosures

All authors: No reported disclosures.