Le Bonheur Children's Hospital

BACKGROUND: Community-acquired pneumonia is a leading infectious cause of hospitalization and death among U.S. adults. Incidence estimates of pneumonia confirmed radiographically and with the use of current laboratory diagnostic tests are needed. METHODS: We conducted active population-based surveillance for community-acquired pneumonia requiring hospitalization among adults 18 years of age or older in five hospitals in Chicago and Nashville. Patients with recent hospitalization or severe immunosuppression were excluded. Blood, urine, and respiratory specimens were systematically collected for culture, serologic testing, antigen detection, and molecular diagnostic testing. Study radiologists independently reviewed chest radiographs. We calculated population-based incidence rates of community-acquired pneumonia requiring hospitalization according to age and pathogen. RESULTS: From January 2010 through June 2012, we enrolled 2488 of 3634 eligible adults (68%). Among 2320 adults with radiographic evidence of pneumonia (93%), the median age of the patients was 57 years (interquartile range, 46 to 71); 498 patients (21%) required intensive care, and 52 (2%) died. Among 2259 patients who had radiographic evidence of pneumonia and specimens available for both bacterial and viral testing, a pathogen was detected in 853 (38%): one or more viruses in 530 (23%), bacteria in 247 (11%), bacterial and viral pathogens in 59 (3%), and a fungal or mycobacterial pathogen in 17 (1%). The most common pathogens were human rhinovirus (in 9% of patients), influenza virus (in 6%), and Streptococcus pneumoniae (in 5%). The annual incidence of pneumonia was 24.8 cases (95% confidence interval, 23.5 to 26.1) per 10,000 adults, with the highest rates among adults 65 to 79 years of age (63.0 cases per 10,000 adults) and those 80 years of age or older (164.3 cases per 10,000 adults). For each pathogen, the incidence increased with age. CONCLUSIONS: The incidence of community-acquired pneumonia requiring hospitalization was highest among the oldest adults. Despite current diagnostic tests, no pathogen was detected in the majority of patients. Respiratory viruses were detected more frequently than bacteria. (Funded by the Influenza Division of the National Center for Immunizations and Respiratory Diseases.).

BACKGROUND: Incidence estimates of hospitalizations for community-acquired pneumonia among children in the United States that are based on prospective data collection are limited. Updated estimates of pneumonia that has been confirmed radiographically and with the use of current laboratory diagnostic tests are needed. METHODS: We conducted active population-based surveillance for community-acquired pneumonia requiring hospitalization among children younger than 18 years of age in three hospitals in Memphis, Nashville, and Salt Lake City. We excluded children with recent hospitalization or severe immunosuppression. Blood and respiratory specimens were systematically collected for pathogen detection with the use of multiple methods. Chest radiographs were reviewed independently by study radiologists. RESULTS: From January 2010 through June 2012, we enrolled 2638 of 3803 eligible children (69%), 2358 of whom (89%) had radiographic evidence of pneumonia. The median age of the children was 2 years (interquartile range, 1 to 6); 497 of 2358 children (21%) required intensive care, and 3 (<1%) died. Among 2222 children with radiographic evidence of pneumonia and with specimens available for bacterial and viral testing, a viral or bacterial pathogen was detected in 1802 (81%), one or more viruses in 1472 (66%), bacteria in 175 (8%), and both bacterial and viral pathogens in 155 (7%). The annual incidence of pneumonia was 15.7 cases per 10,000 children (95% confidence interval [CI], 14.9 to 16.5), with the highest rate among children younger than 2 years of age (62.2 cases per 10,000 children; 95% CI, 57.6 to 67.1). Respiratory syncytial virus was more common among children younger than 5 years of age than among older children (37% vs. 8%), as were adenovirus (15% vs. 3%) and human metapneumovirus (15% vs. 8%). Mycoplasma pneumoniae was more common among children 5 years of age or older than among younger children (19% vs. 3%). CONCLUSIONS: The burden of hospitalization for children with community-acquired pneumonia was highest among the very young, with respiratory viruses the most commonly detected causes of pneumonia. (Funded by the Influenza Division of the National Center for Immunization and Respiratory Diseases.).

IgA nephropathy is a common glomerular disease that is an important cause of kidney failure. This review discusses advances in the therapy and understanding of the molecular basis of IgA nephropathy, a common glomerulopathy that not infrequently leads to kidney failure.

Here we discuss recent advances in understanding the biochemical, immunologic, and genetic pathogenesis of IgA nephropathy, the most common primary glomerulonephritis. Current data indicate that at least four processes contribute to development of IgA nephropathy. Patients with IgA nephropathy often have a genetically determined increase in circulating levels of IgA1 with galactose-deficient O-glycans in the hinge-region (Hit 1). This glycosylation aberrancy is, however, not sufficient to induce renal injury. Synthesis and binding of antibodies directed against galactose-deficient IgA1 are required for formation of immune complexes that accumulate in the glomerular mesangium (Hits 2 and 3). These immune complexes activate mesangial cells, inducing proliferation and secretion of extracellular matrix, cytokines, and chemokines, which result in renal injury (Hit 4). Recent genome-wide association studies identify five distinct susceptibility loci--in the MHC on chromosome 6p21, the complement factor H locus on chromosome 1q32, and in a cluster of genes on chromosome 22q22--that potentially influence these processes and contain candidate mediators of disease. The significant variation in prevalence of risk alleles among different populations may also explain some of the sizable geographic variation in disease prevalence. Elucidation of the pathogenesis of IgA nephropathy provides an opportunity to develop disease-specific therapies.

BACKGROUND Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in infants, and a need exists for prevention of RSV in healthy infants. Nirsevimab is a monoclonal antibody with an extended half-life that is being developed to protect infants for an entire RSV season with a single intramuscular dose. METHODS In this trial conducted in both northern and southern hemispheres, we evaluated nirsevimab for the prevention of RSV-associated lower respiratory tract infection in healthy infants who had been born preterm (29 weeks 0 days to 34 weeks 6 days of gestation). We randomly assigned the infants in a 2:1 ratio to receive nirsevimab, at a dose of 50 mg in a single intramuscular injection, or placebo at the start of an RSV season. The primary end point was medically attended RSV-associated lower respiratory tract infection through 150 days after administration of the dose. The secondary efficacy end point was hospitalization for RSV-associated lower respiratory tract infection through 150 days after administration of the dose. RESULTS From November 2016 through November 2017, a total of 1453 infants were randomly assigned to receive nirsevimab (969 infants) or placebo (484 infants) at the start of the RSV season. The incidence of medically attended RSV-associated lower respiratory tract infection was 70.1% lower (95% confidence interval [CI], 52.3 to 81.2) with nirsevimab prophylaxis than with placebo (2.6% [25 infants] vs. 9.5% [46 infants]; P

BACKGROUND: The development of resistance to antibiotics by many important human pathogens has been linked to exposure to antibiotics over time. The misuse of antibiotics for viral infections (for which they are of no value) and the excessive use of broad spectrum antibiotics in place of narrower spectrum antibiotics have been well-documented throughout the world. Many studies have helped to elucidate the reasons physicians use antibiotics inappropriately. OBJECTIVES: To systematically review the literature to estimate the effectiveness of professional interventions, alone or in combination, in improving the selection, dose and treatment duration of antibiotics prescribed by healthcare providers in the outpatient setting; and to evaluate the impact of these interventions on reducing the incidence of antimicrobial resistant pathogens. SEARCH STRATEGY: We searched the Cochrane Effective Practice and Organisation of Care Group (EPOC) specialized register for studies relating to antibiotic prescribing and ambulatory care. Additional studies were obtained from the bibliographies of retrieved articles, the Scientific Citation Index and personal files. SELECTION CRITERIA: We included all randomised and quasi-randomised controlled trials (RCT and QRCT), controlled before and after studies (CBA) and interrupted time series (ITS) studies of healthcare consumers or healthcare professionals who provide primary care in the outpatient setting. Interventions included any professional intervention, as defined by EPOC, or a patient-based intervention. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed study quality. MAIN RESULTS: Thirty-nine studies examined the effect of printed educational materials for physicians, audit and feedback, educational meetings, educational outreach visits, financial and healthcare system changes, physician reminders, patient-based interventions and multi-faceted interventions. These interventions addressed the overuse of antibiotics for viral infections, the choice of antibiotic for bacterial infections such as streptococcal pharyngitis and urinary tract infection, and the duration of use of antibiotics for conditions such as acute otitis media. Use of printed educational materials or audit and feedback alone resulted in no or only small changes in prescribing. The exception was a study documenting a sustained reduction in macrolide use in Finland following the publication of a warning against their use for group A streptococcal infections. Interactive educational meetings appeared to be more effective than didactic lectures. Educational outreach visits and physician reminders produced mixed results. Patient-based interventions, particularly the use of delayed prescriptions for infections for which antibiotics were not immediately indicated effectively reduced antibiotic use by patients and did not result in excess morbidity. Multi-faceted interventions combining physician, patient and public education in a variety of venues and formats were the most successful in reducing antibiotic prescribing for inappropriate indications. Only one of four studies demonstrated a sustained reduction in the incidence of antibiotic-resistant bacteria associated with the intervention. AUTHORS' CONCLUSIONS: The effectiveness of an intervention on antibiotic prescribing depends to a large degree on the particular prescribing behaviour and the barriers to change in the particular community. No single intervention can be recommended for all behaviours in any setting. Multi-faceted interventions where educational interventions occur on many levels may be successfully applied to communities after addressing local barriers to change. These were the only interventions with effect sizes of sufficient magnitude to potentially reduce the incidence of antibiotic-resistant bacteria. Future research should focus on which elements of these interventions are the most effective. In addition, patient-based interventions and physician reminders show promise and innovative methods such as these deserve further study.

IMPORTANCE: The literature focuses on mortality among children younger than 5 years. Comparable information on nonfatal health outcomes among these children and the fatal and nonfatal burden of diseases and injuries among older children and adolescents is scarce. OBJECTIVE: To determine levels and trends in the fatal and nonfatal burden of diseases and injuries among younger children (aged <5 years), older children (aged 5-9 years), and adolescents (aged 10-19 years) between 1990 and 2013 in 188 countries from the Global Burden of Disease (GBD) 2013 study. EVIDENCE REVIEW: Data from vital registration, verbal autopsy studies, maternal and child death surveillance, and other sources covering 14,244 site-years (ie, years of cause of death data by geography) from 1980 through 2013 were used to estimate cause-specific mortality. Data from 35,620 epidemiological sources were used to estimate the prevalence of the diseases and sequelae in the GBD 2013 study. Cause-specific mortality for most causes was estimated using the Cause of Death Ensemble Model strategy. For some infectious diseases (eg, HIV infection/AIDS, measles, hepatitis B) where the disease process is complex or the cause of death data were insufficient or unavailable, we used natural history models. For most nonfatal health outcomes, DisMod-MR 2.0, a Bayesian metaregression tool, was used to meta-analyze the epidemiological data to generate prevalence estimates. FINDINGS: Of the 7.7 (95% uncertainty interval [UI], 7.4-8.1) million deaths among children and adolescents globally in 2013, 6.28 million occurred among younger children, 0.48 million among older children, and 0.97 million among adolescents. In 2013, the leading causes of death were lower respiratory tract infections among younger children (905.059 deaths; 95% UI, 810,304-998,125), diarrheal diseases among older children (38,325 deaths; 95% UI, 30,365-47,678), and road injuries among adolescents (115,186 deaths; 95% UI, 105,185-124,870). Iron deficiency anemia was the leading cause of years lived with disability among children and adolescents, affecting 619 (95% UI, 618-621) million in 2013. Large between-country variations exist in mortality from leading causes among children and adolescents. Countries with rapid declines in all-cause mortality between 1990 and 2013 also experienced large declines in most leading causes of death, whereas countries with the slowest declines had stagnant or increasing trends in the leading causes of death. In 2013, Nigeria had a 12% global share of deaths from lower respiratory tract infections and a 38% global share of deaths from malaria. India had 33% of the world's deaths from neonatal encephalopathy. Half of the world's diarrheal deaths among children and adolescents occurred in just 5 countries: India, Democratic Republic of the Congo, Pakistan, Nigeria, and Ethiopia. CONCLUSIONS AND RELEVANCE: Understanding the levels and trends of the leading causes of death and disability among children and adolescents is critical to guide investment and inform policies. Monitoring these trends over time is also key to understanding where interventions are having an impact. Proven interventions exist to prevent or treat the leading causes of unnecessary death and disability among children and adolescents. The findings presented here show that these are underused and give guidance to policy makers in countries where more attention is needed.

The ketogenic diet (KD) is an established, effective nonpharmacologic treatment for intractable childhood epilepsy. The KD is provided differently throughout the world, with occasionally significant variations in its administration. There exists a need for more standardized protocols and management recommendations for clinical and research use. In December 2006, The Charlie Foundation commissioned a panel comprised of 26 pediatric epileptologists and dietitians from nine countries with particular expertise using the KD. This group was created in order to create a consensus statement regarding the clinical management of the KD. Subsequently endorsed by the Practice Committee of the Child Neurology Society, this resultant manuscript addresses issues such as patient selection, pre-KD counseling and evaluation, specific dietary therapy selection, implementation, supplementation, follow-up management, adverse event monitoring, and eventual KD discontinuation. This paper highlights recommendations based on best evidence, including areas of agreement and controversy, unanswered questions, and future research.

OBJECTIVE: Worldwide disparities in the provision of surgical care result in otherwise preventable disability and death. There is a growing need to quantify the global burden of neurosurgical disease specifically, and the workforce necessary to meet this demand. METHODS: Results from a multinational collaborative effort to describe the global neurosurgical burden were aggregated and summarized. First, country registries, third-party modeled data, and meta-analyzed published data were combined to generate incidence and volume figures for 10 common neurosurgical conditions. Next, a global mapping survey was performed to identify the number and location of neurosurgeons in each country. Finally, a practitioner survey was conducted to quantify the proportion of disease requiring surgery, as well as the median number of neurosurgical cases per annum. The neurosurgical case deficit was calculated as the difference between the volume of essential neurosurgical cases and the existing neurosurgical workforce capacity. RESULTS: Every year, an estimated 22.6 million patients suffer from neurological disorders or injuries that warrant the expertise of a neurosurgeon, of whom 13.8 million require surgery. Traumatic brain injury, stroke-related conditions, tumors, hydrocephalus, and epilepsy constitute the majority of essential neurosurgical care worldwide. Approximately 23,300 additional neurosurgeons are needed to address more than 5 million essential neurosurgical cases-all in low- and middle-income countries-that go unmet each year. There exists a gross disparity in the allocation of the surgical workforce, leaving large geographic treatment gaps, particularly in Africa and Southeast Asia. CONCLUSIONS: Each year, more than 5 million individuals suffering from treatable neurosurgical conditions will never undergo therapeutic surgical intervention. Populations in Africa and Southeast Asia, where the proportion of neurosurgeons to neurosurgical disease is critically low, are especially at risk. Increasing access to essential neurosurgical care in low- and middle-income countries via neurosurgical workforce expansion as part of surgical system strengthening is necessary to prevent severe disability and death for millions with neurological disease.

Hypertrophic cardiomyopathy (HCM) is a relatively common often inherited global heart disease, with complex phenotypic and genetic expression and natural history, affecting both genders and many races and cultures. Prevalence is 1:200-1:500, largely based on the disease phenotype with imaging, inferring that 750,000 Americans may be affected by HCM. However, cross-sectional data show that only a fraction are clinically diagnosed, suggesting under-recognition, with most clinicians exposed to small segments of the broad disease spectrum. Highly effective HCM management strategies have emerged, altering clinical course and substantially lowering mortality and morbidity rates. These advances underscore the importance of reliable HCM diagnosis with echocardiography and cardiac magnetic resonance. Family screening with noninvasive imaging will identify relatives with the HCM phenotype, while genetic analysis recognizes preclinical sarcomere gene carriers without left ventricular hypertrophy, but with the potential to transmit disease. Comprehensive initial patient evaluations are important for reliable diagnosis, accurate portrayal of HCM and family history, risk stratification, and distinguishing obstructive versus nonobstructive forms.

Fasting and other dietary regimens have been used to treat epilepsy since at least 500 BC. To mimic the metabolism of fasting, the ketogenic diet (KD) was introduced by modern physicians as a treatment for epilepsy in the 1920s. For two decades this therapy was widely used, but with the modern era of antiepileptic drug treatment its use declined dramatically. By the end of the twentieth century this therapy was available in only a small number of children's hospitals. Over the past 15 years, there has been an explosion in the use, and scientific interest in the KD. This review traces the history of one of the most effective treatments for childhood epilepsy.

Serum albumin and prealbumin, well-known visceral proteins, have traditionally been considered useful biochemical laboratory values in a nutrition assessment. However, recent literature disputes this contention. The aim of this document is to clarify that these proteins characterize inflammation rather than describe nutrition status or protein-energy malnutrition. Both critical illness and chronic illness are characterized by inflammation and, as such, hepatic reprioritization of protein synthesis occurs, resulting in lower serum concentrations of albumin and prealbumin. In addition, the redistribution of serum proteins occurs because of an increase in capillary permeability. There is an association between inflammation and malnutrition, however, not between malnutrition and visceral-protein levels. These proteins correlate well with patients' risk for adverse outcomes rather than with protein-energy malnutrition. Therefore, serum albumin and prealbumin should not serve as proxy measures of total body protein or total muscle mass and should not be used as nutrition markers. This paper has been approved by the American Society for Parenteral and Enteral Nutrition Board of Directors.

BACKGROUND: Fractures in children are an important public health issue and a frequent cause of emergency room visits. The purpose of this descriptive epidemiological study was to identify the most frequent pediatric fractures per 1000 population at risk in the United States using the 2010 National Electronic Injury Surveillance System (NEISS) database and 2010 US Census information. METHODS: The NEISS database was queried for all fractures in 2010 in children between the ages of 0 and 19 years. The NEISS national estimates were compared with the 2010 US Census data to extrapolate national occurrence rates. RESULTS: The annual occurrence of fractures increased from ages 0 to 14, peaking in the 10 to 14 age range (15.23 per 1000 children). The annual occurrence rate for the entire pediatric population (0 to 19 y) was 9.47 per 1000 children. Fractures of the lower arm (forearm) were the most common among the entire study population, accounting for 17.8% of all fractures, whereas finger and wrist fractures were the second and third most common, respectively. Finger and hand fractures were most common for age groups 10 to 14 and 15 to 19 years, respectively. The overall risk of a fracture occurring throughout childhood and adolescence was 180 per 1000 children, or just under 1 in every 5 children. CONCLUSIONS: Pediatric fractures represent a significant proportion of pediatric emergency department visits in the United States. Children between 10 and 14 years of age have the highest risk of having fractures. Overall, forearm fractures were the most common pediatric fractures. Most pediatric fractures can be treated on outpatient basis, with only 1 of 18 fractures requiring hospitalization or observation. LEVEL OF EVIDENCE: Level III-Retrospective comparative study.

IgA nephropathy (IgAN), major cause of kidney failure worldwide, is common in Asians, moderately prevalent in Europeans, and rare in Africans. It is not known if these differences represent variation in genes, environment, or ascertainment. In a recent GWAS, we localized five IgAN susceptibility loci on Chr.6p21 (HLA-DQB1/DRB1, PSMB9/TAP1, and DPA1/DPB2 loci), Chr.1q32 (CFHR3/R1 locus), and Chr.22q12 (HORMAD2 locus). These IgAN loci are associated with risk of other immune-mediated disorders such as type I diabetes, multiple sclerosis, or inflammatory bowel disease. We tested association of these loci in eight new independent cohorts of Asian, European, and African-American ancestry (N = 4,789), followed by meta-analysis with risk-score modeling in 12 cohorts (N = 10,755) and geospatial analysis in 85 world populations. Four susceptibility loci robustly replicated and all five loci were genome-wide significant in the combined cohort (P = 5×10⁻³²-3×10⁻¹⁰), with heterogeneity detected only at the PSMB9/TAP1 locus (I² = 0.60). Conditional analyses identified two new independent risk alleles within the HLA-DQB1/DRB1 locus, defining multiple risk and protective haplotypes within this interval. We also detected a significant genetic interaction, whereby the odds ratio for the HORMAD2 protective allele was reversed in homozygotes for a CFHR3/R1 deletion (P = 2.5×10⁻⁴). A seven-SNP genetic risk score, which explained 4.7% of overall IgAN risk, increased sharply with Eastward and Northward distance from Africa (r = 0.30, P = 3×10⁻¹²⁸). This model paralleled the known East-West gradient in disease risk. Moreover, the prediction of a South-North axis was confirmed by registry data showing that the prevalence of IgAN-attributable kidney failure is increased in Northern Europe, similar to multiple sclerosis and type I diabetes. Variation at IgAN susceptibility loci correlates with differences in disease prevalence among world populations. These findings inform genetic, biological, and epidemiological investigations of IgAN and permit cross-comparison with other complex traits that share genetic risk loci and geographic patterns with IgAN.

Hypertrophic cardiomyopathy (HCM), a relatively common, globally distributed, and often inherited primary cardiac disease, has now transformed into a contemporary highly treatable condition with effective options that alter natural history along specific personalized adverse pathways at all ages. HCM patients with disease-related complications benefit from: matured risk stratification in which major markers reliably select patients for prophylactic defibrillators and prevention of arrhythmic sudden death; low risk to high benefit surgical myectomy (with percutaneous alcohol ablation a selective alternative) that reverses progressive heart failure caused by outflow obstruction; anticoagulation prophylaxis that prevents atrial fibrillation-related embolic stroke and ablation techniques that decrease the frequency of paroxysmal episodes; and occasionally, heart transplant for end-stage nonobstructive patients. Those innovations have substantially improved outcomes by significantly reducing morbidity and HCM-related mortality to 0.5%/y. Palliative pharmacological strategies with currently available negative inotropic drugs can control symptoms over the short-term in some patients, but generally do not alter long-term clinical course. Notably, a substantial proportion of HCM patients (largely those identified without outflow obstruction) experience a stable/benign course without major interventions. The expert panel has critically appraised all available data and presented management insights and recommendations with concise principles for clinical decision-making.

INTRODUCTION: An increase in the incidence and severity of acute osteoarticular infections in children was perceived after the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) in our community. This study was performed to describe changes in the epidemiology and clinical features of acute osteoarticular infections. METHODS: The records of patients discharged from Le Bonheur Children's Medical Center with a diagnosis of acute osteoarticular infection between 2000 and 2004 were reviewed. Data regarding signs and symptoms, diagnostic testing, therapeutics, surgery, and hospital course were collected. RESULTS: There were 158 cases of acute osteoarticular infection. The incidence increased from 2.6 to 6.0 per 1000 admissions between 2000 and 2004. The proportion of infections caused by methicillin-susceptible S. aureus (MSSA) remained constant (10%-13%) and that caused by MRSA rose from 4% to 40%. There was no difference between MRSA and MSSA patients in the duration of fever or pain before diagnosis. Seventy-one percent of patients with MRSA had subperiosteal abscesses compared with 38% with MSSA (P = 0.02). Ninety-one percent of MRSA patients required a surgical procedure compared with 62% of MSSA patients (P < 0.001). Median hospital stay was 7 days for MSSA patients and 10 days for MRSA patients (P = 0.0001). Three patients developed chronic osteomyelitis, 2 with MRSA. There was no association between a delay in institution of appropriate antibiotic therapy and presence of subperiosteal abscess (P = 0.8). CONCLUSIONS: There has been an increase in the incidence and severity of acute osteoarticular infections in Memphis. Patients with community-associated MRSA infections are at higher risk of subperiosteal abscess requiring surgical intervention.

Secondary bacterial infections often complicate respiratory viral infections, but the mechanisms whereby viruses predispose to bacterial disease are not completely understood. We determined the effects of infection with respiratory syncytial virus (RSV), human parainfluenza virus 3 (HPIV-3), and influenza virus on the abilities of nontypeable Haemophilus influenzae and Streptococcus pneumoniae to adhere to respiratory epithelial cells and how these viruses alter the expression of known receptors for these bacteria. All viruses enhanced bacterial adhesion to primary and immortalized cell lines. RSV and HPIV-3 infection increased the expression of several known receptors for pathogenic bacteria by primary bronchial epithelial cells and A549 cells but not by primary small airway epithelial cells. Influenza virus infection did not alter receptor expression. Paramyxoviruses augmented bacterial adherence to primary bronchial epithelial cells and immortalized cell lines by up-regulating eukaryotic cell receptors for these pathogens, whereas this mechanism was less significant in primary small airway epithelial cells and in influenza virus infections. Respiratory viruses promote bacterial adhesion to respiratory epithelial cells, a process that may increase bacterial colonization and contribute to disease. These studies highlight the distinct responses of different cell types to viral infection and the need to consider this variation when interpreting studies of the interactions between respiratory cells and viral pathogens.

Background: The epidemiology of Mycoplasma pneumoniae (Mp) among US children (<18 years) hospitalized with community-acquired pneumonia (CAP) is poorly understood. Methods: In the Etiology of Pneumonia in the Community study, we prospectively enrolled 2254 children hospitalized with radiographically confirmed pneumonia from January 2010-June 2012 and tested nasopharyngeal/oropharyngeal swabs for Mp using real-time polymerase chain reaction (PCR). Clinical and epidemiological features of Mp PCR-positive and -negative children were compared using logistic regression. Macrolide susceptibility was assessed by genotyping isolates. Results: One hundred and eighty two (8%) children were Mp PCR-positive (median age, 7 years); 12% required intensive care and 26% had pleural effusion. No in-hospital deaths occurred. Macrolide resistance was found in 4% (6/169) isolates. Of 178 (98%) Mp PCR-positive children tested for copathogens, 50 (28%) had ≥1 copathogen detected. Variables significantly associated with higher odds of Mp detection included age (10-17 years: adjusted odds ratio [aOR], 10.7 [95% confidence interval {CI}, 5.4-21.1] and 5-9 years: aOR, 6.4 [95% CI, 3.4-12.1] vs 2-4 years), outpatient antibiotics ≤5 days preadmission (aOR, 2.3 [95% CI, 1.5-3.5]), and copathogen detection (aOR, 2.1 [95% CI, 1.3-3.3]). Clinical characteristics were non-specific. Conclusions: Usually considered as a mild respiratory infection, Mp was the most commonly detected bacteria among children aged ≥5 years hospitalized with CAP, one-quarter of whom had codetections. Although associated with clinically nonspecific symptoms, there was a need for intensive care in some cases. Mycoplasma pneumoniae should be included in the differential diagnosis for school-aged children hospitalized with CAP.

Constitutive overexpression of the MDR1 (multidrug resistance) gene, which encodes a multidrug efflux pump of the major facilitator superfamily, is a frequent cause of resistance to fluconazole and other toxic compounds in clinical Candida albicans strains, but the mechanism of MDR1 upregulation has not been resolved. By genome-wide gene expression analysis we have identified a zinc cluster transcription factor, designated as MRR1 (multidrug resistance regulator), that was coordinately upregulated with MDR1 in drug-resistant, clinical C. albicans isolates. Inactivation of MRR1 in two such drug-resistant isolates abolished both MDR1 expression and multidrug resistance. Sequence analysis of the MRR1 alleles of two matched drug-sensitive and drug-resistant C. albicans isolate pairs showed that the resistant isolates had become homozygous for MRR1 alleles that contained single nucleotide substitutions, resulting in a P683S exchange in one isolate and a G997V substitution in the other isolate. Introduction of these mutated alleles into a drug-susceptible C. albicans strain resulted in constitutive MDR1 overexpression and multidrug resistance. By comparing the transcriptional profiles of drug-resistant C. albicans isolates and mrr1Delta mutants derived from them and of C. albicans strains carrying wild-type and mutated MRR1 alleles, we defined the target genes that are controlled by Mrr1p. Many of the Mrr1p target genes encode oxidoreductases, whose upregulation in fluconazole-resistant isolates may help to prevent cell damage resulting from the generation of toxic molecules in the presence of fluconazole and thereby contribute to drug resistance. The identification of MRR1 as the central regulator of the MDR1 efflux pump and the elucidation of the mutations that have occurred in fluconazole-resistant, clinical C. albicans isolates and result in constitutive activity of this trancription factor provide detailed insights into the molecular basis of multidrug resistance in this important human fungal pathogen.

Whether p38 and extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase cascades are required for inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF) accumulation in RAW 264.7 murine macrophages exposed to lipopolysaccharide (LPS) plus recombinant interferon-gamma (rIFN-gamma) was investigated. By use of Western blotting for iNOS detection and ELISA for quantitation of TNF secretion, three selective inhibitors of these pathways were tested (the p38 inhibitors SB202190 and SB203580 and the MEK 1,2/ERK inhibitor PD98059). Dose-related inhibition of iNOS production was demonstrated when inhibitors were added 1 h before, simultaneously with, or 1 h after LPS plus rIFN-gamma stimulation. In contrast, inhibition of TNF secretion was observed only when cells were preincubated with these agents. Thus, both the p38 and ERK pathways are involved in the up-regulation of iNOS and TNF production by murine macrophages, and specific inhibitors of these pathways block macrophage iNOS production even when added 1 h after activation of these cells.