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Resumen Objetivos Analizar las caracteristicas fisicas, antropometricas y formativas de los reanimadores asociadas a la correcta compresion y reexpansion toracica durante la reanimacion cardiopulmonar. Metodologia Estudio observacional prospectivo. Profesionales y estudiantes sanitarios de urgencias y cuidados criticos realizaron 2 min de compresiones toracicas sobre un maniqui. Se evaluo la profundidad y la presion residual tras las compresiones, y se estudio su asociacion a diferentes variables (fisicas, antropometricas y formativas) mediante la creacion de modelos de regresion logistica. Resultados Participaron 238 voluntarios. Que el reanimador tuviese una experiencia previa en menos de 6 reanimaciones cardiopulmonares (OR: 3,03; IC 95%: 1,2-7,63) se asocio a una mayor probabilidad de no lograr una profundidad adecuada en las compresiones. Una mayor estatura (OR: 0,93; IC 95%: 0,87-0,99) y fuerza de aprehension (OR: 0,94; IC 95%: 0,89-0,99) fueron condiciones que actuaron como factores predisponentes a la ejecucion de una tecnica correcta. Ninguna caracteristica se asocio a la adecuacion de la reexpansion toracica. Conclusiones La experiencia previa del reanimador es el factor mas fuertemente asociado a la correcta ejecucion de las compresiones toracicas. En menor medida, tambien influye la estatura y la fuerza del tren superior del profesional. No se han identificado factores asociados a la adecuacion de la reexpansion toracica tras las compresiones.

Resumen Objetivos Identificar los medicamentos intravenosos de uso comun en el ambito hospitalario con capacidad de producir dano endotelial. Metodo Estudio experimental in vitro. La muestra estuvo formada por 62 medicamentos de uso comun en los servicios de urgencias y hospitalizacion. Las variables estudiadas fueron la osmolaridad y el pH. Posteriormente, en base a esos valores, se determino la capacidad teorica para provocar dano endotelial, clasificandola en alta, moderada y baja. Resultados Se analizaron 19 medicamentos para fluidoterapia, 21 antibioticos y 22 medicamentos intravenosos. Las soluciones de glucosa, el bicarbonato 1M y el manitol 10% presentaron una capacidad elevada para provocar irritacion venosa. Vancomicina, ciprofloxacino, amiodarona, haloperidol y labetalol mostraron una capacidad irritativa elevada derivada de su pH marcadamente acido. Los antibioticos, dexketoprofeno, diazepam, digoxina, etomidato, fenitoina, levetiracetam y metamizol presentaron valores extremos de osmolaridad en su presentacion reconstituida o sin diluir, y mantuvieron sus valores de tonicidad elevados despues de diluirlos en 100 ml de suero salino el diazepam, la digoxina y la fenitoina. Conclusiones Conocer el pH y la osmolaridad de los medicamentos intravenosos permite evaluar su capacidad para provocar dano endotelial. La creacion de tablas comprensivas en base a las propiedades quimicas de los medicamentos puede constituir una herramienta util que contribuya a prevenir la flebitis quimicamente inducida.

Rat bite fever is a systemic illness most commonly caused by Streptobacillus moniliformis that is classically characterized by fever, rash and migratory polyarthritis. Here, we highlight the highly variable clinical presentations of rat bite fever in children and the importance of maintaining a high degree of suspicion so appropriate treatment can be promptly initiated.

Although vaccination has reduced the incidence of Haemophilus influenzae type b, nontypeable H. influenzae and other encapsulated types remain a health threat. Little is known regarding the contemporary molecular epidemiology of these organisms. We conducted multilocus sequence typing on invasive H. influenzae during a period of increasing incidence.

Randomized simulation trial to analyze dispatcher-assisted cardiopulmonary resuscitation instructions provided from the emergency call center in an out-of-hospital heart arrest assisted by lay persons. An analysis of the telephone instructions was performed using a 14-item checklist by two external researchers. Simulations lasted nine minutes. Twenty-one volunteers were enrolled. All of them started resuscitation maneuvers. Telephone instructions were verbalized in very heterogeneous ways. Half of the indicators exceeded 90% compliance. Frequently the recommendation of push hard and fast on the patient’s chest was omitted and the dispatcher tended to mark a slower compression rate. The average time from the call to the start of the resuscitation was 3 min 33 s (SD: 1 min 7 s). The telephone instructions were verbalized in a very heterogeneous way. It is necessary to standardize and provide training in how to guide a dispatcher-assisted resuscitation.

Geminiviruses (viruses with circular, single-stranded DNA genomes) are one of the major groups of plant viruses causing severe economic problems for agriculture worldwide. The control of these pathogens has become a priority to maintain the production of important crops, including cotton, maize, cassava, and other vegetables. Obtaining resistant plants is the most powerful strategy and a key factor to stablish an effective integrated pest management for a robust control. In the last few decades, numerous studies have successfully approached that goal using diverse strategies based on plant variability or on the engineered expression of proteins/RNAs. The increasing knowledge of the mechanisms involved in the geminivirus-plant-vector interactions, in combination with the development of gene editing technology and nanoparticles, draw new and promising strategies for a durable control of these emerging pathogens.

Paranasal sinuses (PNS) infections are common in children. They may cause common and well-known complications, but also, unusual and potentially devastating complications. Diagnosing PNS infections and complications in children requires knowledge of the unique anatomy of the nasal cavity and the PNS. In fetal life, nasal mucosa evaginations into the lateral nasal walls initiate the development of the PNS. The PNS continue to develop after birth and complete their maturation and pneumatization at different ages during childhood which makes the pattern of PNS infections determined by patient age. Complications are caused by direct spread of the infection to the orbit, face, intracranial or osseous structures or hematogenous spread of the infection to the intracranial structures. Emergent imaging studies are often necessary in the evaluation of the complications in pediatric patients when the symptoms persist for 10 days and/or if there is evidence of intracranial or orbital complications. In addition, immunocompromised children are especially vulnerable to developing unusual complications. Computed tomography (CT) is excellent for determining whether there is intraorbital extension of PNS disease. However, when the infection approaches the orbital apex, a magnetic resonance imaging (MRI) study with contrast is necessary to assess spread into the cavernous sinus and the intracranial compartment. The goal of this manuscript is to review and characterize imaging findings of PNS infections using CT and MRI allowing determination of the extent of PNS infections and their common and unusual complications in children. In addition, a summary of the development of the normal PNS is provided.

BACKGROUND AND PURPOSE: Bacterial meningitis most commonly affects young children and can result in critical adverse outcomes, including sensorineural hearing loss (SNHL). The purpose of this study is to determine the diagnostic accuracy of MR imaging for predicting the development of SNHL among infants with bacterial meningitis. MATERIALS AND METHODS: A retrospective review was performed among infants (age

Background The Streptococcus anginosus group (SAG, S. anginosus, S. intermedius and S. constellatus) are often associated with severe disease and abscess formation. In our institution, we observed an apparent increase in frequency of intraorbital and intracranial infections resulting from SAG at Texas Children's Hospital. We undertook a retrospective review to describe the frequency and clinical features of these infections. Methods We reviewed the database of the microbiology laboratory at Texas Children's Hospital from 2011 to 2018 for SAG-positive cultures. Cases included were those associated with (1) either otitis media or sinusitis and (2) Pott's puffy tumor, orbital abscesses, mastoiditis, epidural abscesses, subdural empyema, brain parenchymal abscesses or dural enhancement by imaging. The number of overall diagnoses were determined using diagnostic codes and used to estimate the proportion of disease caused by SAG. Results Ninety-five cases were identified meeting inclusion criteria. The median age of patients was 11.4 years, and 75.8% were previously healthy. S. intermedius was most commonly isolated (80%) followed by S. constellatus (12.6%) and S. anginosus (7.4%); 50.5% of cases were polymicrobial. Among polymicrobial cases, Staphylococcus aureus was most frequently isolated. All patients underwent surgical intervention. 8.4% of patients experienced persistent neurologic deficits. We observed a significant increase in disease incidence during the study period; in addition, the overall proportion of all intracranial infections caused by SAG increased. Conclusions Complications of otitis media and sinusitis caused by SAG are associated with substantial morbidity. These infections are becoming increasingly common at our center although the precise reason for this temporal trend is unclear.

Lymphocytic meningoradiculitis (Bannwarth syndrome) is a rare manifestation of Lyme neuroborreliosis in children. It is the most common clinical manifestation of early Lyme neuroborreliosis in adults in European countries where the disease is endemic but is rare in children. We report an imported case of Bannwarth syndrome in a pediatric patient and review the literature for other pediatric cases reported.

BACKGROUND AND PURPOSE: Group B Streptococcus and Escherichia coli (E coli) are the 2 most common causes of bacterial meningitis in neonates. The purpose of this study was to determine whether CSF and/or MR imaging findings differ between infants with group B streptococcal or E coli meningitis. MATERIALS AND METHODS: A retrospective review was performed among neonates (younger than 28 days) and infants (younger than 120 days) with proved group B streptococcal (n = 57) or E coli meningitis (n = 50). A CSF or blood culture positive for Streptococcus or E coli and an elevated CSF white blood cell count were used as the criterion standard. Independent, blinded review of brain MRIs obtained within 21 days of presentation were performed by 2 board-certified neuroradiologists. CSF laboratory values and MR imaging findings were compared between the groups. RESULTS: There was no statistically significant difference between the mean age at presentation for patients with group B streptococcal (40 days; range, 2–111 days) versus patients with E coli meningitis (31 days; range, 12–115 days) (P = .18). There was no statistically significant difference in the CSF white blood cell count, glucose, or protein. There was a significant difference between group B streptococcal and E coli meningitis in the frequency of hydrocephalus (0% versus 22%, P = .001) and infarct (40% versus 14%; P = .038), respectively. There was no statistically significant difference in leptomeningeal enhancement, cerebritis, ventriculitis, abscess/granuloma, subdural effusion, extra-axial purulent material, intraventricular purulent material, hemorrhage, and sinus thrombosis. CONCLUSIONS: Although neonates and infants with group B streptococcal or E coli meningitis had similar age and CSF laboratory values, patients with group B streptococcal meningitis more frequently demonstrated infarcts, while those with E coli meningitis more frequently had early onset of hydrocephalus.

Resumen Objetivo Determinar el riesgo de contaminacion microbiologica de los humidificadores de burbujeo para oxigenoterapia de alto o bajo flujo de uso hospitalario. Metodos Revision sistematica de la literatura a traves de 6 bases de datos bibliograficas. Se seleccionaron estudios observacionales o experimentales publicados entre 1990 y 2016, en ingles o espanol, que analizaban la contaminacion microbiana de los humidificadores de burbujeo de los dispositivos de oxigenoterapia hospitalaria de alto y bajo flujo. Resultados Se incluyeron 12 articulos: 4 analizaron el agua de humidificadores reutilizables, 4 de desechables y otros 4 compararon muestras procedentes de ambos modelos. Se observo la presencia de contaminacion microbiana en todos los estudios que evaluaron humidificadores reutilizables (generalmente bacterias habituales de la flora cutanea). En 2 de ellos se notificaron aislamientos de especies potencialmente patogenicas. No se aislo contaminacion microbiana en las muestras procedentes de modelos desechables, independientemente de si fueron utilizados por un unico paciente o por varios de forma consecutiva a lo largo del tiempo. Conclusion Parece existir bajo riesgo de contaminacion en humidificadores desechables durante las primeras semanas de uso, pudiendo reutilizarse entre pacientes distintos sin riesgo de contaminacion cruzada. Por otro lado, cabe destacar que la manipulacion de los humidificadores reutilizables de forma no aseptica puede aumentar la probabilidad de contaminacion, por lo que la sustitucion de humidificadores reutilizables por modelos desechables podria ser la opcion mas segura.

We investigated the microbiology, management, and orthopedic outcomes of osteoarticular infections in infants age ≤1 year at our institution. Among 87 patients, Staphylococcus aureus was the most common pathogen (44.8%), followed by group B Streptococcus. Twenty-nine patients (33%), with a median age of 9.2 months, were transitioned to oral antibiotic therapy after ≤14 days of parenteral therapy; orthopedic outcomes were similar to those with prolonged parenteral therapy.

Background While the majority of pediatric osteomyelitis cases are acute in nature, a significant subset present with prolonged symptoms often associated with substantial morbidity. Little data exist to guide clinicians in the management of these infections. We sought to describe the epidemiology, clinical features and management of chronic osteomyelitis (CO) in children. Methods We reviewed hospital admissions for CO from 2011 to 2018 at Texas Children's Hospital. Cases were included if symptoms lasted ≥28 days on presentation. Cases were classified as those associated with: (1) a contiguous focus of infection; (2) penetrating trauma; (3) orthopedic hardware; (4) postacute CO (PACO, those occurring after ≥28 days of therapy for acute osteomyelitis); and (5) primary hematogenous CO. Results One hundred fourteen cases met inclusion criteria. The median patient age was 11.8 years and 35.9% had comorbidities. 70.2% of patients underwent ≥1 surgical procedure. A microbiologic etiology was identified in 72.8% of cases and Staphylococcus aureus was most common (39.4%). Contiguous focus of infection was more often associated with polymicrobial disease with or without Pseudomonas. Postacute CO was caused by S. aureus in 95%. The median duration of total therapy was 210 days. 26.3% of patients experienced treatment failure of which 46% underwent repeat hospital admission/surgery. There was no association between duration of intravenous therapy for CO and treatment failure. Conclusions Children with CO represent a diverse group both in terms of pathogenesis and microbiology. Pathogenesis and clinical presentation can provide clues to microbiologic etiology. Prolonged intravenous therapy does not appear to improve outcomes in CO.

BACKGROUND: Staphylococcus aureus is a common pathogen seen in pediatric bloodstream infections. Currently, no evidence-based recommendations are used to guide decisions on the number of follow-up blood cultures (FUBCs) needed to demonstrate infection clearance. Unnecessary cultures increase the risk of false-positives, add to health care costs, and create additional trauma to children and their families. In this study, we examined risk factors for persistent S aureus bacteremia (SAB) and intermittent positive blood cultures (positive cultures obtained after a documented negative FUBC result) to determine the number of FUBCs needed to demonstrate infection clearance in children. METHODS: Patients ≤18 years who were hospitalized with SAB at Texas Children’s Hospital in 2018 were reviewed. We assessed the impact of an infectious disease diagnosis (central line–associated bloodstream infection, osteomyelitis, soft tissue infection, endocarditis, etc) and medical comorbidities on bacteremia duration. Patients with intermittent positive blood cultures were studied to determine the characteristics of this group and overall frequency of reversion to positive cultures. RESULTS: A total of 122 subjects met the inclusion criteria. The median duration of bacteremia was 1 day (interquartile range: 1–2 days). Only 19 patients (16%) had bacteremia lasting ≥3 days, all of whom had a diagnosis of central line–associated bloodstream infection, osteomyelitis, or endocarditis. Intermittent positive cultures occurred in 5% of patients, with positive cultures after 2 negative FUBC results seen in CONCLUSIONS: On the basis of our sample of children with SAB, additional blood cultures to document sterility are not necessary after 2 FUBC results are negative in well-appearing patients.

Most cases of pediatric osteoarticular infections (OAIs) are hematogenous in nature and caused by Staphylococcus aureus. OAI in children can also occur through direct inoculation of microorganisms secondary to penetrating or open trauma. No studies in the United States have evaluated the microbiology or outcomes of trauma-related OAI (TROAI) in children in the era of community-acquired methicillin-resistant S. aureus (CA-MRSA).Cases were identified from the inpatient infectious diseases consultation database at Texas Children's Hospital from January 2011 to December 2016. TROAI cases were those in which OAI developed following a clear history of penetrating trauma, open fracture, crush injury or traumatic amputation. Only cases with radiographic evidence of bone abscess, gross appearance of infection at the time of surgery and/or positive cultures from bone or joint were included. Complications included recurrence of infection, pathologic fracture or chronic osteomyelitis.During the study period, 692 consultations for OAI were performed, with 34 meeting inclusion criteria. In 68%, at least 1 organism was isolated, and the most commonly isolated organisms were S. aureus (32% overall, 21% MRSA) and Enterobacter cloacae (24%). Polymicrobial infections occurred in 38% of patients. Eighty-five percentage of patients had at least 1 surgical procedure, and 38% underwent ≥ 2 procedures. Eighty-two percentage of patients were discharged on oral therapy. Complications developed in 15% of patients and were more commonly associated with E. cloacae (80% vs. 14%, P = 0.007) and fungi (P = 0.03).TROAI are relatively uncommon in children but cause significant morbidity. While MRSA contributes substantially to TROAI, the highly diverse microbiology emphasizes the importance of obtaining cultures for microbiologic diagnosis and management. Clinicians should be aware of the frequency of E. cloacae in TROAI and its high risk for sequelae.

Ibrutinib is an inhibitor of Bruton's tyrosine kinase (BTK) that is used for the treatment of multiple hematologic malignancies including chronic lymphocytic leukemia (CLL) with promising outcomes. Its use has been associated with significant side effects including diarrhea, fatigue, infections, arthralgias, hemorrhage, and atrial fibrillation among others. Ibrutinib-associated adverse events have led to its discontinuation in more than one-fifth of CLL patients treated. Specifically, in the real-world setting, 21% to 30% of patients have needed an Ibrutinib dose interruption or reduction. Moreover, the associated toxicity seems to be more prominent in the geriatric population given the poor functional reserve, impaired mobility, and preexisting comorbidities. In the elderly, moderate to severe treatment-related toxicity often times leads to a higher number of hospitalizations, which ultimately increases the risk of complications and health care costs. Some studies have reported that Ibrutinib dose reductions have not had a significant impact on the progression-free-survival or overall survival in the general population. Nevertheless, there is not sufficient data or consent about the use of a reduced dose of Ibrutinib for treatment of CLL in frail older adults. In addition, annual costs of treatment with complete-dose Ibrutinib for veterans exceed $100,000. As it is common to reach complete remission with Ibrutinib monotherapy, patients will remain on therapy long-term, compounding financial impact over their treatment lifetime. Reduced dose Ibrutinib can lower total cost by 50% or more and thereby increase patient adherence due to decreased economic burden. Therefore, we present a retrospective review of a series of 7 cases involving frail older adults with CLL treated with Ibrutinib at the Washington DC Veterans Affairs Medical Center. Six out of seven patients received a reduced Ibrutinib dose and had a complete response whereas one patient received the dose recommended by the manufacturer leading to a prolonged hospital stay due to the adverse effects. We report the disease control evidenced by a decrease in white blood cell count, alleviation of "B symptoms", and resolution of lymphadenopathy along with side effects with an Ibrutinib dose ranging from 140 to 280 mg per day. We also report the cost benefits obtained with the use of a reduced Ibrutinib dose. We hope that sharing our experience encourages clinical trials aiming to determine the minimal dose needed to effectively treat CLL while limiting toxicity, decreasing health care costs, and preserving quality of life in frail older adults. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Septic arthritis (SA) and acute osteomyelitis (AO) are among the most common serious bacterial infections of childhood. Knowledge of the microbiology of SA is critical to treatment. Awareness of the presence of attendant AO is also important to guide clinical management. We sought to describe the current microbiology of SA in children and clinical features associated with coexisting AO.Patients with SA were identified from the infectious diseases consult service records from 2010 to 2014. Patients with penetrating/open trauma and orthopedic hardware in situ were excluded.A total of 168 patients with SA were included. The most common causative organism was Staphylococcus aureus accounting for 47.7% of cases (29.1% were methicillin-susceptible S. aureus and 18.5% were methicillin-resistant S. aureus), followed by group A streptococcus (GAS, 8.9%). The proportion of cases due to GAS increased from 2011 to 2014 (3.3%-16.7%; P = 0.1). One hundred eight (64.3%) patients had concurrent AO. The presence of osteomyelitis was associated with older median age (5.9 vs. 2.4 years; P = 0.04), a longer duration of symptoms (5 vs. 2.5 days; P0.001), S. aureus (62.1% vs. 21.7%; P0.001), bacteremia (46.2% vs. 20.3%; P = 0.001), a longer duration of fever after admission (5 vs. 2 days; P0.001) and a longer length of stay (10 vs. 6 days; P0.001).Methicillin-resistant S. aureus continues to be an important cause of SA though GAS may be increasing in frequency. The presence of concomitant osteomyelitis is higher than previously reported and associated with older age, a longer duration of symptoms and fever, bacteremia and S. aureus.

Background The emergence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) in the late 1990s-early 2000s complicated the empiric management of suspected staphylococcal infection in children. Rising clindamycin resistance rates in many communities adds further to management challenges. Ceftaroline, an anti-MRSA cephalosporin, represents an attractive therapy option. Little data are available, however, regarding the frequency of reduced susceptibility (RS) to ceftaroline among MRSA isolates from a general pediatric population. Methods Isolates were selected from an ongoing S. aureus surveillance study at Texas Children’s Hospital. Invasive MRSA isolates from 2015-2018 were included. Isolates were initially screened for ceftaroline RS with E-test; all isolates with a ceftaroline E-test MIC ≥ 1.5µg/ml underwent ceftaroline broth dilution. Ceftaroline RS was regarded as an MIC ≥ 2 µg/ml; full ceftaroline resistance was defined as an MIC ≥ 8 μg/ml. Accessory gene regulator (agr) groups were characterized by PCR. Results 201 viable isolates were included. The ceftaroline MIC50 and MIC90 were 0.5 and 1 µg/ml, respectively (Figure 1). Six isolates had MIC ≥ 2 µg/ml (2.9%) with two having MIC ≥ 8 µg/ml (0.9%). All ceftaroline RS isolates were from healthcare associated infections. Ceftaroline RS isolates were more often associated with clindamycin-resistance and agr group II (Figure 2). Infections with ceftaroline RS were associated with central venous lines, recent ICU admission, preceding antibiotic exposure (specifically cephalosporins) and prior MRSA infection. One subject with MRSA CLABSI had a ceftaroline susceptible MRSA infection followed < 1 month later by a ceftaroline resistant infection (MIC =32 μg/ml); the isolates were identical by PFGE. Only 3 subjects had previously received ceftaroline, none of which subsequently developed a ceftaroline RS isolate. Figure 1. Ceftaroline MIC Distribution Figure 2. Clinical And Microbiologic Associations with Reduced Ceftaroline Susceptibility Conclusion Ceftaroline RS occurs in 2.9% of invasive MRSA isolates in children and is most prominent among healthcare-associated infections. These isolates were associated with clindamycin resistance and agr group II. While ceftaroline RS is rare among invasive MRSA infections, the lack of preceding ceftaroline exposure is concerning and warrants careful surveillance. Disclosures Sheldon L. Kaplan, MD, Allergan (Research Grant or Support)Pfizer (Grant/Research Support) Jonathon C. McNeil, MD, Allergan (Research Grant or Support, Allergan provided ceftaroline powder for use in studies described in this abstract)

Background While the majority of pediatric osteomyelitis cases are acute in nature, a significant subset present with prolonged symptoms often associated with substantial morbidity. Little data exist to guide clinicians in the management of these infections. We sought to describe the epidemiology, clinical features and management of chronic osteomyelitis in children. Methods We reviewed hospital admissions with an ICD10 code for chronic osteomyelitis from 2011-2018 at Texas Children’s Hospital. Cases were included if symptoms lasted >28 days on presentation. Patients diagnosed with chronic recurrent multifocal osteomyelitis were excluded. Cases were classified as those 1) associated with a contiguous focus (CoF), 2) penetrating or open trauma, 3) orthopedic hardware (OH), 4) post-acute chronic osteomyelitis (PACO, those occurring after >28 days of therapy for acute osteomyelitis) and 5) primary hematogenous chronic osteomyelitis (PHCO, those with 28 days of symptoms without other clear risk factors). Results 114 cases met inclusion criteria. The median patient age is 11.8 years and 35.9% patients had underlying comorbidities. 83% of patients underwent a surgical procedure. Cases were diverse in terms of pathogenesis (Figure 1). A microbiologic etiology was identified in 72.8% of cases and was polymicrobial in 20.2% of cases; Staphylococcus aureus was the single most common etiology (Figure 2). CoF infection was more often associated with polymicrobial etiology with or without Pseudomonas (P< 0.001) and disease of the foot. PACO was caused by S. aureus in 95% of cases (p< 0.001, Figure 3). The overall median duration of total therapy was 210 days. 41% were discharged from hospital on OPAT with or without later transition to oral antibiotics. 26.3% of patients had persistent functional limitations at time of last follow-up of which 46% experienced repeat hospital admission/surgery. There was no association between duration of intravenous therapy and persistent functional limitations. Figure 1. Categories of Chronic Osteomyelitis Figure 2. Microbiology of Pediatric Chronic Osteomyelitis Figure 3. Clinical Features of Pediatric Chronic Osteomyelitis Conclusion Children with chronic osteomyelitis are diverse both in terms of pathogenesis and microbiology. Pathogenesis and clinical presentation can provide clues to microbiologic etiology. Prolonged intravenous therapy does not appear to improve functional outcomes in chronic osteomyelitis Disclosures Jonathon C. McNeil, MD, Allergan (Research Grant or Support, Allergan provided ceftaroline powder for use in studies described in this abstract)

The association between Salmonella spp. and osteoarticular infections in pediatric patients with major sickle hemoglobinopathies has been well established. However, the contemporary microbiology of these infections in such patients is unknown. We conducted a retrospective review of medical records at Texas Children's Hospital in Houston from 2000 to 2018 to investigate this question. Fifty cases were identified. In 23 (46%) cases, a pathogen was identified. Salmonella was the most common pathogen isolated, accounting for 61% of culture-positive cases followed by Staphylococcus aureus (21.7%).

In this paper, MCFS (Min-Cut-based feature-selection) is presented, which is a feature-selection algorithm based on the representation of the features in a dataset by means of a directed graph. The main contribution of our work is to show the usefulness of a general graph-processing technique in the feature-selection problem for classification datasets. The vertices of the graphs used herein are the features together with two special-purpose vertices (one of which denotes high correlation to the feature class of the dataset, and the other denotes a low correlation to the feature class). The edges are functions of the correlations among the features and also between the features and the classes. A classic max-flow min-cut algorithm is applied to this graph. The cut returned by this algorithm provides the selected features. We have compared the results of our proposal with well-known feature-selection techniques. Our algorithm obtains results statistically similar to those achieved by the other techniques in terms of number of features selected, while additionally significantly improving the accuracy.

Background Staphylococcus aureus is the most common cause of acute hematogenous osteoarticular infections (AHOAIs) in children. The risk factors for the development of orthopedic complications (OC) after AHOAI are poorly understood. We sought to describe clinical and microbiologic variables present on the index admission that may predict OC in S. aureus AHOAI. Methods Staphylococcus aureus AHOAI cases were identified from 2011–2017 at Texas Children’s Hospital and reviewed for the development of OC. OC included chronic osteomyelitis, growth arrest, avascular necrosis, chronic dislocation, and pathologic fracture. All S. aureus isolates were characterized by pulsed-field gel electrophoresis and agr group. Results A total of 286 cases were examined of which 27 patients (9.4%) developed OC. Patients who developed OC more often had infection with an agr group III organism (P = .04), bacteremia (P = .04), delayed source control (P < .001), ≥2 surgical procedures (P < .001), intensive care unit admission (P = .09), and fever >4 days after admission (P = .008). There was no association with OC and patient age, methicillin resistance, or choice/route of antibiotics. In multivariable analyses of OC, infection with agr group III S. aureus, prolonged fever, and delayed source control remained statistically significant. Conclusions OC develop following S. aureus AHOAI in 9.4% of cases. Although the development of OC is likely multifactorial, agr group III organisms, prolonged fever, and delayed source control are independently associated with OC. Moreover, early aggressive surgical source control may be beneficial in children with S. aureus AHOAI.

Innovations in surgical techniques and medical technology have allowed for the improved survival and quality of life of children with complex congenital heart disease as well as those with arrhythmias and cardiomyopathies. With increased interventions to aid these children comes the potential for risk of complex infections associated with surgery and implantation of devices and hardware. The management of such infections is often challenging and requires a multidisciplinary approach including infectious diseases specialists, cardiologists, and surgeons. This chapter briefly reviews surgical site infections, including mediastinitis, in children undergoing cardiothoracic surgery as well as infections complicating cardiac implantable electronic devices and ventricular assist devices.

Coagulase-negative staphylococci (CoNS) are a common cause of pediatric ventricular shunt infections. The Infectious Diseases Society of America recommends vancomycin serum troughs of 15–20 µg/mL when treating CoNS shunt infections in adult patients. We report a series of pediatric cases of CoNS shunt infections in which clinical cure was obtained with troughs < 15 µg/mL. These findings question the relevance of this recommendation in pediatric patients.

Strains of methicillin-resistant Staphylococcus aureus (MRSA), particularly those belonging to the USA300 pulsotype, have been well described to cause severe osteoarticular infections (OAIs). A vancomycin MIC of ≥1.5 μg/ml has been demonstrated to contribute to disease severity in adults with MRSA and even methicillin-susceptible S. aureus (MSSA) bacteremia. Little data exist describing the outcomes of MSSA OAIs in terms of molecular characteristics and vancomycin MIC. All patients/isolates were chosen from a surveillance study at Texas Children's Hospital (TCH). S. aureus OAI isolates were identified from 2011 to 2016 and subjected to vancomycin Etests, pulsed-field gel electrophoresis (PFGE), and PCR to determine Panton-Valentine leucocidin (PVL) production and agr group. Two hundred fifty-two cases of S. aureus OAI were identified; 183 cases were MSSA (72.6%). During the study period, a decrease in the proportion of cases secondary to MRSA was observed, declining from 37.8% to 15.9% ( P = 0.02). Of the MSSA isolates, 26.2% and 23.5% were USA300 and PVL positive, respectively. An increase in the proportion of MSSA isolates with a vancomycin MIC of ≥1.5 μg/ml occurred in the study period ( P = 0.004). In MSSA, an elevated vancomycin MIC was associated with multiple surgical procedures and venous thromboses, even when adjusting for empirical β-lactam use. An increase in vancomycin MIC was noted among isolates belonging to agr group 4 during the study period. Methicillin resistance is declining among S. aureus OAI isolates at TCH. Simultaneously, vancomycin Etest MICs are increasing among MSSA isolates. Vancomycin MICs of ≥2 μg/ml are associated with adverse clinical outcomes in MSSA irrespective of antibiotic choice, suggesting that this may be a surrogate for organism virulence.

Background Osteoarticular infections (OAI) are common in patients with major sickle hemoglobinopathies (Hemoglobin [Hgb] SS, Hgb SC, and Hgb Sβ thalassemia). Although Salmonella spp. cause a substantial number of OAIs in these patients, contemporary data regarding the most common etiology in the era of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) are lacking. This introduces challenges for selecting empiric antimicrobial therapy. We evaluated the microbiology and management of OAI in children with sickle hemoglobinopathies. Methods Children with sickle hemoglobinopathies admitted to Texas Children’s Hospital with acute hematogenous OAI from 2011 to 2018 were identified based on ICD10 codes and the consult database of the pediatric infectious diseases service. Culture-negative cases were included if treated for OAI. Medical records were reviewed. Statistical analyses were conducted with STATA ver. 13. Results 36 patients met inclusion criteria; 53% were diagnosed with isolated osteomyelitis and 47% with osteomyelitis and septic arthritis. In 42% a microbial etiology was identified (Figure 1) with Salmonella spp. being the most common (n = 7, 47%) followed by S. aureus (n = 5, 33%).11 (31%) patients had subperiosteal or intraosseous abscesses and 26 (72%) underwent diagnostic and/or therapeutic surgical procedures; 36% had positive blood cultures. Children with Salmonella spp. infections had a longer duration of fever (median-5, range: 4–9 days) compared with those caused by other pathogens (median-2, range: 0–6 days; P = 0.04). The median duration of IV therapy was longer in culture-positive than culture-negative cases (30 vs.10 days, P = 0.009); the total duration of therapy was similar for all cases (32 days, IQR: 28–42). No patients were readmitted due to OAI. Conclusion At our institution, Salmonella spp. were the most common cause of OAI among children with sickle hemoglobinopathies. Subperiosteal/intraosseous abscess formation and the need for surgical procedures were common. The role of oral antibiotics for the treatment of Salmonella OAI in patients with sickle hemoglobinopathies warrants further study. Disclosures All authors: No reported disclosures.

Background Select methicillin-susceptible Staphylococcus aureus (MSSA) strains may produce β-lactamases with an affinity for first-generation cephalosporins (1GC). In the setting of a high inoculum, these β-lactamases may promote clinically meaningful cleavage of 1GCs, potentially resulting in antibiotic failure, a phenomenon known as the cefazolin inoculum effect (CIE). Acute hematogenous osteoarticular infections (AHOAIs, including osteomyelitis and septic arthritis) are the most common manifestation of invasive S. aureus infection in children. We evaluated the prevalence and potential impact of CIE among MSSA AHOAI isolates at two children’s hospitals. Methods MSSA AHOAI isolates were obtained through surveillance studies at Texas Children’s and St. Louis Children’s Hospitals from January 2011 to December 2018. Isolates were tested for CIE via a macrobroth dilution assay with an inoculum of 107 CFU/mL; CIE was defined as a cefazolin MIC ≥16 µg/mL. Isolates were characterized by accessary gene regulator group (agr). The subsequent development of chronic osteomyelitis (CO) was regarded as a clinically important outcome. Results A total of 287 cases were included and the median patient age was 8.6 years. 14.3% of isolates exhibited CIE; CIE prevalence was similar across study sites. 74.6% of patients received a 1GC as definitive therapy. CIE isolates were more often resistant to clindamycin, belonged to agr III and associated with CO (Figure 1); a numerically higher rate of CO was observed with CIE isolates regardless of definitive antibiotic choice (Figure 2). In multivariable analyses, bone abscesses, agr III, positive blood cultures, multiple surgeries, and delayed source control but not CIE were independently associated with CO (Figure 3); similar results were seen if analyses were restricted to only those receiving 1GC. Conclusion CIE is exhibited by 14.3% of MSSA AHOAI isolates in children. CIE is associated with agr III and clindamycin-resistant strains. agr III strains are independently associated with CO; thus negative outcomes reported with CIE may more accurately reflect strain-dependent virulence factors rather than true antibiotic failure. Further studies are necessary to better understand the clinical significance of these findings. Disclosures All Authors: No reported Disclosures.

Aim To determine the risk of microbiological contamination with hospital use high- and low-flow bubbling humidifiers. Methods A systematic literature review was carried out in 6 databases. Observational or experimental studies published between 1990 and 2016 were selected, written in English or Spanish, and in which microbiological contamination with hospital use high- and low-flow bubbling humidifiers was investigated. Results A total of 12 articles were included: 4 analyzed the water from reusable humidifiers, 4 analyzed the water from prefilled system humidifiers, and the rest compared samples from both models. Microbial contamination was observed in all studies in which reusable humidifiers were evaluated, usually involving common bacteria from the skin flora, while potential pathogenic species were notified in 2 studies. No microbial contamination was isolated from reusable humidifiers, regardless of whether they had been consecutively used over time by a single patient or by several patients. Conclusion On one hand, there seems to be a low risk of contamination during the first weeks of use of prefilled humidifiers, which allows multiple use in different patients, without a risk of cross-contamination. On the other hand, it should be underscored that handling reusable humidifiers without correct aseptic measures can increase the risk of contamination; replacing reusable humidifiers with prefilled models therefore could be the safest option.

Central nervous system (CNS) infections caused by Staphylococcus aureus are uncommon in pediatric patients. We review the epidemiology, clinical features and treatment in 68 patients with a S. aureus CNS infection evaluated at Texas Children's Hospital.Cases of CNS infection in children with positive cerebrospinal fluid cultures or spinal epidural abscess (SEA) for S. aureus at Texas Children's Hospital from 2001 to 2013 were reviewed.Seventy cases of S. aureus CNS infection occurred in 68 patients. Forty-nine cases (70%) were secondary to a CNS device, 5 (7.1%) were postoperative meningitis, 9 (12.8%) were hematogenous meningitis and 7 (10%) were SEAs. Forty-seven (67.2%) were caused by methicillin-sensitive S. aureus (MSSA) and 23 (32.8%) by methicillin-resistant S. aureus (MRSA). Community-acquired infections were more often caused by MRSA that was clone USA300/pvl. Most patients were treated with nafcillin (MSSA) or vancomycin (MRSA) with or without rifampin. Among patients with MRSA infection, 50% had a serum vancomycin trough obtained with the median level being 10.6 μg/mL (range: 5.4-15.7 μg/mL). Only 1 death was associated with S. aureus infection.The epidemiology of invasive of S. aureus infections continues to evolve with MSSA accounting for most of the infections in this series. The majority of cases were associated with neurosurgical procedures; however, hematogenous S. aureus meningitis and SEA occurred as community-acquired infections in patients without predisposing factors. Patients with MRSA CNS infections had a favorable response to vancomycin, but the beneficial effect of combination therapy or targeting vancomycin trough concentrations of 15-20 μg/mL remains unclear.

Elevated vancomycin minimum inhibitory concentrations (MICs) in Staphylococcus aureus have been associated with worse clinical outcomes in adults. For invasive meticillin-resistant S. aureus (MRSA) infections in adults, the Infectious Diseases Society of America recommends targeting vancomycin serum trough concentrations between 15 and 20 μg/mL. We evaluated trends in vancomycin MICs from healthcare-associated (HCA) S. aureus bacteremia isolates in children in addition to correlating vancomycin serum trough levels with clinical outcomes.Patients and isolates were identified from a prospective S. aureus surveillance study at Texas Children's Hospital (TCH). HCA S. aureus bacteremia isolates from 2003 to 2013 were selected. Vancomycin MICs by E-test were determined and medical records were reviewed. Acute kidney injury (AKI) was defined as doubling of the baseline serum creatinine.Three hundred forty-one isolates met inclusion criteria. We observed a reverse vancomycin creep among MRSA isolates in the study period with a decline in the proportion of isolates with vancomycin MIC ≥ 2 μg/mL (from 32.7% to 5.6%; P0.001). However, the proportion of MSSA isolates with MIC ≥ 2 μg/mL increased (from 2.9% to 9%; P = 0.04). Among patients who had vancomycin troughs performed, there was no difference in duration of bacteremia or fever with vancomycin trough15 versus15 μg/mL. A vancomycin trough15 μg/mL was, however, an independent risk factor for AKI.Vancomycin MICs are shifting among HCA S. aureus bacteremia isolates with significant differences between MRSA and MSSA at TCH. Higher vancomycin troughs did not improve outcomes in pediatric HCA S. aureus bacteremia but were associated with increased nephrotoxicity. Further studies are needed to better understand optimal management of children with S. aureus bacteremia.

Background Staphylococcus aureus is the most common cause of acute hematogenous osteoarticular infections (AHOAIs) in children. While the vast majority of patients do well, a small proportion experience significant morbidity, including chronic infection and pathologic fractures. We sought to describe clinical and microbiologic variables present on the index admission that may predict long-term orthopedic complications (OC). Methods Cases of S. aureus AHOAI were identified from 2011 to 2016 at Texas Children’s Hospital (TCH). All cases were reviewed for the development of OC until April 1, 2018. OC included chronic osteomyelitis (CO), growth arrest/limb length discrepancy, avascular necrosis, chronic dislocation, and pathologic fracture (PF) with or without angular deformity. All S. aureus isolates were characterized by PCR for Panton–Valentine Leukocidin (PVL) genes and agr group. Statistical Analyses were performed with STATA. Results A total of 252 cases were identified meeting inclusion criteria (figure). Twenty-four (9.5%) developed OC; of which, 50% were CO and 25% PF. Patients who developed CO more often had positive blood cultures during the index admission (P < 0.001), surgical drainage after hospital day 2 (33.3% vs. 8.8%, P = 0.02) as well as a longer time to 50% reduction in C-reactive protein (CRP, 9 vs. 7 days, P = 0.01). Patients who developed PF more often had infection due to PVL-positive organisms (83.3% vs. 38.6%, P = 0.03) and had a longer duration of fever after admission (9.5 vs. 2.5 days, P = 0.03). Overall, OC were associated with ICU admission (P = 0.04), a slower decline in CRP (P = 0.02) and a greater proportion of patients with surgery after hospital day 2 (P = 0.04) as well as infection secondary to agr III isolates (P = 0.03). There was no statistically significant relationship between OC and patient age, affected bone, time to initiation of effective antimicrobial therapy, duration of intravenous therapy, or final antibiotic choice. Conclusion Patients with S. aureus AHOAI with a delay in source control, slow decline in CRP, prolonged fever or ICU admission are at higher risk of OC. While nonspecific, these findings suggest that such patients may warrant especially cautious clinical follow-up to identify sequelae early. Large multicenter studies are needed to better predict OC in this setting. Disclosures All authors: No reported disclosures.

Background The Streptococcus anginosus group (SAG), including S. anginosus, S. intermedius and S. constellatus, are common flora of the oral cavity, respiratory tree and gastrointestinal tract. However, these organisms have the potential to cause serious invasive infections and are notably pyogenic. We observed an apparent increase in the frequency of intraorbital and intracranial infections resulting from SAG at Texas Children’s Hospital (TCH). We undertook a retrospective review to describe the frequency and clinical features of these infections. Methods We reviewed the database of the clinical microbiology laboratory at TCH from 2011 to 2018 for SAG-positive cultures. For purposes of this study, cases included were those associated with 1) either otitis media or sinusitis and 2) Pott’s Puffy Tumor, orbital abscesses, epidural abscesses, subdural empyema, brain parenchymal abscesses, dural enhancement by imaging or mastoiditis. Similar methods were used for SAG identification throughout the study period. The number of cases per year was used along with annual hospital admissions data to estimate case rate; case rate trends were examined using linear regression. Results 950 cultures positive for SAG were identified by the clinical lab; 95 cases met inclusion criteria. The median age of patients was 11.4 years. Specific diagnoses are presented in Figure 1. S. intermedius was most commonly isolated (81.1%) followed by S. constellatus (12.6%) and S. anginosus (7.4%); 50.5% of cases were polymicrobial. Among polymicrobial cases, S. aureus was most frequently isolated (25%). All patients underwent surgical intervention and 20.5% underwent ≥2 procedures (Figure 2). 16.8% were associated with intracranial thromboses and 4.2% with CNS infarcts; 8.4% of patients experienced persistent neurologic deficits. All isolates were susceptible to penicillin. We observed an increase in the annual disease rate during the study (Figure 3, P = 0.01). Conclusion Complications of otitis media and sinusitis due to SAG are associated with substantial morbidity. These infections are becomingly increasingly common at our center although the precise reason for this temporal trend is unclear. Multicenter studies are needed to validate these epidemiologic findings. Disclosures All authors: No reported disclosures.

Nowadays, people do not only navigate the web, but they also contribute contents to the Internet. Among other things, they write their thoughts and opinions in review sites, forums, social networks, blogs and other websites. These opinions constitute a valuable resource for businesses, governments and consumers. In the last years, some researchers have proposed opinion extraction systems, mostly domain-independent ones, to automatically extract structured representations of opinions contained in those texts. In this work, we tackle this task in a domain-oriented approach, defining a set of domain-specific resources which capture valuable knowledge about how people express opinions on a given domain. These resources are automatically induced from a set of annotated documents. Some experiments were carried out on three different domains (user-generated reviews of headphones, hotels and cars), comparing our approach to other state-of-the-art, domain-independent techniques. The results confirm the importance of the domain in order to build accurate opinion extraction systems. Some experiments on the influence of the dataset size and an example of aggregation and visualization of the extracted opinions are also shown.

Bacteremia is often one factor used in deciding the need for prolonged intravenous antimicrobial therapy in osteoarticular infections (OAIs). We examined treatment practices and outcomes of Staphylococcus aureus bacteremic osteoarticular infections (BOAIs) evaluated at Texas Children's Hospital.Cases of acute hematogenous OAI in children with positive blood cultures for S. aureus at Texas Children's Hospital between 2011 and 2014 were reviewed. Orthopedic complications included chronic osteomyelitis, growth arrest, pathologic fracture, avascular necrosis and chronic dislocation. Acute kidney injury was defined as a doubling of the baseline creatinine.One hundred and ninety-two cases of S. aureus OAI were identified with 102 cases of BOAI included [35 methicillin-resistant S. aureus (MRSA)]. Twenty-five patients were discharged home on oral antibiotics. Patients discharged on oral antibiotics had a shorter duration of fever, had a more rapid decline in C-reactive protein and were less likely to have MRSA. The frequency of orthopedic complications did not increase in patients who received early transition to oral antibiotics. For patients with MRSA bacteremia, the rates of complications between those who received ≥7 days versus7 days of vancomycin did not differ. Vancomycin serum troughs15 µg/mL were not associated with a decreased duration of fever, bacteremia or hospitalization, need for repeat operation or orthopedic complications but were associated with acute kidney injury.S. aureus BOAIs are associated with substantial morbidity. Early transition to oral therapy may be a safe option for select patients with S. aureus BOAI, including those due to MRSA. Prolonged courses of vancomycin and vancomycin troughs15 μg/mL were not associated with improved outcomes for MRSA OAI.

BACKGROUND AND OBJECTIVE: Acute hematogenous osteomyelitis (AHO) is a severe infection in children. Drainage of purulent collections in bones provides specimens for culture as well as therapeutic benefit. Interventional radiology (IR)-guided procedures may serve as a less invasive means of culture in select patients. We examined the impact of IR and surgically obtained cultures in the diagnosis and management of AHO. METHODS: A retrospective review of cases of AHO was performed from 2011 to 2014. Patients with chronic disease, orthopedic hardware, puncture wounds, or an infected contiguous focus were excluded. RESULTS: A total of 250 cases met inclusion criteria. Blood cultures were positive in 107 of 231 cases (46.3%), and 123 of 150 patients had positive cultures (82%) obtained by orthopedic surgery. Of these 123 patients, 62 (50.4%) had organisms identified only through operating room (OR) cultures. Of the 66 patients who had cultures obtained by IR, 34 (51.5%) had positive IR cultures. For those with positive IR cultures, 18 (52.9%) had negative blood cultures. Among the 80 patients with negative blood culture and positive OR/IR culture, the results changed antibiotic therapy in 68 (85%) patients. CONCLUSIONS: IR or OR culture was the only means of identifying a pathogen in 80 of 216 cases (37%), and in >80% changed medical management. IR can be used effectively to obtain bone cultures in children with AHO not requiring open surgical drainage. Further research is needed to better understand the optimal utilization of IR and OR culture in pediatric AHO.

One of the strategies utilized to decrease infections in the hospital setting relies on topical antimicrobials and antiseptics. While their use is beneficial, concerns arise over the potential to develop resistance or tolerance to these agents. We examined nosocomial Staphylococcus aureus isolates from 2007 to 2013 for the presence of genes associated with tolerance to chlorhexidine. Isolates and patients were identified from an S. aureus surveillance study at Texas Children's Hospital. Nosocomial S. aureus isolates (those causing infection at ≥72 h of hospitalization) were identified and underwent PCR for the qacA or qacB ( qacA/B ) and smr genes associated with elevated minimum bactericidal concentrations of chlorhexidine. Molecular typing with pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and agr typing and a review of the medical record were performed. Two hundred forty-seven nosocomial S. aureus infections were identified. Overall, 111 isolates carried one or both genes (44.9%); 33.1% were positive for smr , 22.7% were positive for qacA/B , and 10.9% of the isolates possessed both genes. The smr -positive isolates were more often resistant to methicillin, ciprofloxacin, and/or clindamycin. The isolates positive for qacA/B were more often associated with indwelling central venous catheters and a vancomycin MIC of ≥2 μg/ml. Isolates carrying either smr or qacA/B were associated with a diagnosis of bacteremia. The smr -positive isolates more often belonged to sequence type 8 (ST8) than the isolates that were positive for qacA/B . Mupirocin resistance was detected in 2.8% of the isolates. Antiseptic-tolerant S. aureus strains are common in our children's hospital and are associated with decreased susceptibility to other systemic antimicrobials and with bloodstream infections. Further work is needed to understand the implications that these organisms have on the hospital environment and antiseptic use in the future.

Infectious diseases in pediatric otolaryngology : , Infectious diseases in pediatric otolaryngology : , کتابخانه دیجیتال جندی شاپور اهواز

Toll-like receptors (TLRs), a family of surface molecules, are involved in innate immune responses. Recent studies indicated that TLRs play a critical role in inflammatory responses to exogenous and endogenous triggers. This article focuses on probable effects of TLRs in the morbidity of cardiovascular events, e.g., ischemic reperfusion (I/R) injury and atherosclerosis. TLR2 and TLR4 have been shown to have the most fundamental role in promoting cytokine production and subsequent inflammatory damages in these states. Blockade of these receptors may be beneficial in both preventing the occurrence and decreasing the complications in cardiovascular events. However, controversies exist on the certainty of this beneficial effect; therefore, additional studies are needed.

Trust and Reputation Systems constitute an essential part of many social networks due to the great expansion of these on-line communities in the past few years. As a consequence of this growth, some users try to disturb the normal atmosphere of these communities, or even to take advantage of them in order to obtain some kind of benefits. Therefore, the concept of trust is a key point in the performance of on-line systems such as on-line marketplaces, review aggregators, social news sites, and forums. In this work we propose a method to compute a ranking of the users in a social network, regarding their trustworthiness. The aim of our method is to prevent malicious users from illicitly gaining high reputation in the network by demoting them in the ranking of users. We propose a novel system intended to propagate both positive and negative opinions of the users through a network, in such way that the opinions from each user about others influence their global trust score. Our proposal has been evaluated in different challenging situations. The experiments include the generation of random graphs, the use of a real-world dataset extracted from a social news site, and a combination of both a real dataset and generation techniques, in order to test our proposals in different environments. The results show that our method performs well in every situations, showing the propagation of trust and distrust to be a reliable mechanism in a Trust and Reputation System.

Background Most cases of pediatric osteoarticular infections (OAI) are hematogenous in nature and secondary to Staphylococcus aureus. The emergence of community-acquired MRSA (CA-MRSA) in the early 2000s led to an evolution of disease presentation and management for pediatric OAI. OAI in children can also occur through direct inoculation of microorganisms secondary to penetrating or open trauma. No studies have evaluated the microbiology or outcomes of trauma-related OAI (TROAI) in children in the era of CA-MRSA. Methods Cases were identified from the inpatient infectious diseases consultation database at Texas Children’s Hospital from Jan 1, 2011- Dec 31, 2016. TROAI cases were those in which OAI developed following a clear history of penetrating trauma, open fracture, crush injury or traumatic amputation. Only cases with radiographic evidence of bone abscess, gross appearance of infection at time of surgery and/or positive cultures from bone or joint were included. Complications included recurrence of infection, pathologic fracture or chronic osteomyelitis. Results 692 consultations for OAI were performed during the study period with 32 meeting inclusion criteria; TROAI accounted for 2.8/10,000 hospital admissions. The median age of patients was 8.53 years. In 65.6% at least one organism was isolated and the most commonly isolated organisms were S. aureus (25%, 15.6% MRSA) and Enterobacter cloacae (25%, Figures 1 and 2). 83.9% of patients had at least one surgical procedure and 43.8% underwent ≥2 procedures. The presence of fungi (P = 0.01), atypical mycobacteria (P = 0.04), MRSA (P = 0.02) and/or polymicrobial infection (P = 0.001) were more common among cases requiring multiple surgeries. 84.4% of patients were discharged on oral therapy. 12.5% of patients developed complications and this was more common with E. cloacae (37.5% vs. 4.2%, P = 0.03). Conclusion TROAI are relatively uncommon in children but cause significant morbidity. While MRSA contributes substantially to TROAI and is associated with multiple surgical procedures, the highly diverse microbiology emphasizes the importance of obtaining cultures for microbiologic diagnosis and management. Clinicians should be aware of the frequency of E. cloacae in TROAI and its high risk for sequelae. Disclosures S. L. Kaplan, Allergan: Grant Investigator, Grant recipient and This grant pertains to unrelated research

This paper presents the ideas, experiments and specifications related to the Supervised TextRank (STR) technique, a word tagging method based on the TextRank algorithm. The main innovation of STR technique is the use of a graph-based ranking algorithm similar to PageRank in a supervised fashion, gathering the information needed to build the graph representations of the text from a tagged corpus. We also propose a flexible graph specification language that allows to easily experiment with multiple configurations for the topology of the graph and for the information associated to the nodes and the edges. We have carried experiments in the Part-Of-Speech task, a common tagging problem in Natural Language Processing. In our best result we have achieved a precision of 96.16%, at the same level of the best tagging tools.

The objective of our study was to assess the variations in the 3D organization of Chromosome Territories (CT) of chromosomes 9 and 22 in lymphocytes from healthy subjects. The differences in the distances of CTs 9 and 22 between subjects may provide a new perspective in the predisposition for specific chromosome translocations. We quantified the intra- and inter-subject variation in the distance of CT 9 and 22 as a proof of concept for new questions on the physiological and pathological effects of these differences. Methods: Blood samples from healthy subjects were processed for the isolation of lymphocytes with Ficoll as the gradient media. After the isolation, we fixed the cells directly onto coverslips for a 3D Fish protocol with 9 and 22 whole chromosome probes. Our protocol has been standardized to maintain the integrity of the nucleus with only minor changes in its volume. After the hybridization, we used the Elyra System of Zeiss to obtain super resolution images in Z stack. The images were processed with the Imaris software for its 3D reconstruction, measurement (distances, volumes and colocalization) and analysis. Results: The CTs 9 and 22 behave differently in peripheral blood lymphocytes. The CT 22 has a more internal position (closer to the center of the nucleus) in comparison with the CT 9, which can be seen most of the times in contact with the border of the nucleus. The CT 22 occupies a smaller volume than CT 9, which has almost a twice as larger volume. The CTs 9 have a polarized distribution inside the nucleus, therefore the distance between the CT 9-9 was larger (~7.3 μm ± 0.9) than the distance between CT 22-22. Although the position of the CTs was highly variable in cells from the same individual, we found a statistically significant difference in the inter-individual distance between CT 9-9 and the minimal distance between CT 9-22. Conclusion: Our study suggests that there are differences in the distribution of CT in lymphocytes isolated from peripheral blood between our subjects. These differences could prove to be a new individual characteristic with important implications in the predisposition for specific diseases, mainly to those related with chromosomal rearrangements. Citation Format: David G. Vallejo, Eunice Fabian, Luis A. Herrera. Variance in the distance between chromosome territories 9 and 22 in lymphocytes from peripheral blood healthy subjects: A proof of concept for a possible risk factor in chronic myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3378.

In this paper we present InstanceRank, a ranking algorithm that reflects the relevance of the instances within a dataset. InstanceRank applies a similar solution to that used by PageRank, the web pages ranking algorithm in the Google search engine. We also present ISR, an instance selection technique that uses InstanceRank. This algorithm chooses the most representative instances from a learning database. Experiments show that ISR algorithm, with InstanceRank as ranking criteria, obtains similar results in accuracy to other instance reduction techniques, noticeably reducing the size of the instance set.

This paper examines the use of lung weight increase as an indicator of seawater drowning compared to the amount of Sr absorbed by the blood. The study population was limited to male victims older than 20 years. Significant differences between cases of drowning and “non-drowning” were detected in terms of the lung–heart weight ratio ( L / H ) ( p L / B ) ( p = 0.005). However, using lung weight ( L ), L / H or L / B to distinguish between seawater drownings and saltwater non-drownings some overlap was produced. The factor rendering least overlap was L / B , which also appeared to be non-dependent on the victim's age. Our findings suggest that a value of L / B higher than 19.5 g/kg could be a useful indicator of death by drowning, but that when a lower value is found, additional drowning diagnoses would be needed to establish the manner of death.