A Common Variant of Staphylococcal Cassette Chromosome mec Type IVa in Isolates from Copenhagen,Denmark, Is Not Detected by the BD GeneOhm Methicillin-Resistant Staphylococcus aureus Assay

Rapid tests for detection of methicillin-resistant Staphylococcus aureus (MRSA) carriage are important to limit the transmission of MRSA in the health care setting. We evaluated the performance of the BD GeneOhm MRSA real-time PCR assay using a diverse collection of MRSA isolates, mainly from Copenhagen, Denmark, but also including international isolates, e.g., USA100-1100. Pure cultures of 349 MRSA isolates representing variants of staphylococcal cassette chromosome mec (SCCmec) types I to V and 103 different staphylococcal protein A (spa) types were tested. In addition, 53 methicillin-susceptible Staphylococcus aureus isolates were included as negative controls. Forty-four MRSA isolates were undetectable; of these, 95% harbored SCCmec type IVa, and these included the most-common clone in Copenhagen, spa t024-sequence type 8-IVa. The false-negative MRSA isolates were tested with new primers (analyte-specific reagent [ASR] BD GeneOhm MRSA assay) supplied by Becton Dickinson (BD). The ASR BD GeneOhm MRSA assay detected 42 of the 44 isolates that were false negative in the BD GeneOhm MRSA assay. Combining the BD GeneOhm MRSA assay with the ASR BD GeneOhm MRSA assay greatly improved the results, with only two MRSA isolates being false negative. The BD GeneOhm MRSA assay alone is not adequate for MRSA detection in Copenhagen, Denmark, as more than one-third of our MRSA isolates would not be detected. We recommend that the BD GeneOhm MRSA assay be evaluated against the local MRSA diversity before being established as a standard assay, and due to the constant evolution of SCCmec cassettes, a continuous global surveillance is advisable in order to update the assay as necessary.Methicillin-resistant Staphylococcus aureus (MRSA) is a common nosocomial pathogen in countries all over the world. In recent years, community-associated MRSA (CA-MRSA) has become increasingly prevalent and has shown potential to cause health care-associated bloodstream infections (8, 26). Screening and isolation of MRSA-positive patients is essential to control the transmission of MRSA in hospitals (16, 24). However, conventional detection of MRSA by culture takes at least 48 h before a preliminary result is available, and as patients in many countries are only isolated when they are recognized as MRSA positive, the risk of having already transmitted MRSA is high. The real-time PCR BD GeneOhm MRSA assay (Becton Dickinson [BD] Diagnostics GeneOhm; San Diego, CA), formerly called IDI-MRSA, is one of a number of commercial kits for rapid MRSA detection directly from nasal swabs (7) and is based on primers developed by Huletsky et al. (18). The forward primers bind to the J3 region of the staphylococcal cassette chromosome mec (SCCmec), and the reverse primer binds in the orfX region that is specific for Staphylococcus aureus. At least seven SCCmec types are known (types I to VII) (3), and several subtypes, especially of type IV, have been described (21, 27).The BD GeneOhm MRSA assay has been tested in a number of studies (4, 5, 10, 11, 13-15, 22, 23, 25, 29-31). Most studies screened hospitalized patients, but only two studies described the SCCmec types of their MRSA isolates (15, 25). Therefore, it is possible that only a few predominant hospital clones with the same SCCmec types were tested. In Denmark, different CA-MRSA clones dominate and MRSA isolates mainly harbor SCCmec types IV (85%) and V (6%) (2). In-house testing with the Huletsky primers (18) revealed that they did not amplify a PCR fragment from our most-common MRSA clone, spa t024-sequence type 8 (ST8)-IVa. Based on this finding and with the knowledge of the high number of type IV subtypes known, we were interested in finding out whether the BD GeneOhm MRSA assay could detect MRSA isolates from a collection that included mainly CA-MRSA strains. We tested 349 MRSA isolates representing variants of SCCmec types I to V. Furthermore, we chose MRSA isolates of different staphylococcal protein A (spa) types to have a broad range of genetic backgrounds, testing the hypothesis that the same SCCmec type might have minor differences in different MRSA lineages and that these differences could be in the primer regions of the assay.     

Visits to complementary and alternative medicine providers by children and adolescents in the United States.

OBJECTIVE: Determine the prevalence, patterns, costs, and predictors of visits to complementary and alternative medicine (CAM) providers and subsequent remedy use in a nationally representative pediatric sample. METHODS: The 1996 Medical Expenditure Panel Survey provided data on 7371 subjects < or =21 years of age. The primary outcome variable was CAM provider visits as defined by consulting a CAM provider "for health reasons." Predictors included sociodemographics, family resources, health status, parental CAM use, and perceptions and use of conventional medical care. Bivariate analyses and logistic regression determined independent factors associated with CAM use. RESULTS: Overall, 2.0% used CAM. Only 12.3% disclosed this use to their usual source of care (USC). The most common providers were chiropractors and clergy or spiritualists. The most common therapies were herbal remedies and spiritual healing. Mean amount spent per person on CAM visits was 73.40 US dollars and on remedies was 13.06 US dollars. Weighted estimates to the national pediatric population of annual expenditures on CAM visits and remedies were 127 million US dollars and 22 million US dollars, respectively. Significant factors independently associated with CAM visits were female gender, older age, good and very good perceived physical health as compared with excellent health, parental CAM use, and dissatisfaction with the quality of care received from the USC. CONCLUSIONS: Two percent of parents reported that their children consulted a CAM provider and rarely disclosed this use to their USC. While dissatisfaction with the quality of care by the USC and less good perceived physical health predicted CAM visits, parental CAM use was the most predictive.     

Differences in adhesion receptor expression between immature and older platelets and red blood cells of neonates and adults

PURPOSE: To examine the hypothesis that reticulated platelets and reticulocytes show elevated adhesion receptor expression compared with mature cells in both adult and neonatal cells. METHODS: Flow cytometry was used to examine laminin, fibronectin (VLA-6), and thrombospondin (glycoprotein IV [GPIV]) expression in reticulated red cells, reticulated platelets, and older peripherally circulating mature red cells and mature platelets in seven newborn cord blood samples and blood samples from eight adult volunteers. RESULTS: The difference in the neonatal reticulated platelet percentage of 9.2+/-14.8% was not statistically significant from the adult reticulated platelet percentage of 5.0+/-1.5% in this small population. There was a statistically significant difference between the reticulated cord blood red cell mean of 7.7+/-1.8% and the adult mean of 3.1+/-0.43%. Mean expression of VLA-6 was 96% in adult reticulated platelets, 79% in adult mature platelets, 81% in cord reticulated platelets and 65% in cord mature platelets. Mean expression of GPIV was similar, with corresponding values of 90%, 71%, 78%, and 57%. Reticulated red cells in adults averaged 44% VLA-4 and 46% GPIV; cord reticulocytes were 9% and 15%, respectively. CONCLUSIONS: Reticulated cells newly released from the bone marrow express more adhesive receptors than mature cells in both groups. Cord blood samples showed hypoexpression of both receptor types in red blood cells and platelets.     

Prior knowledge of illumination for 3D perception in the human brain

In perceiving 3D shape from ambiguous shading patterns, humans use the prior knowledge that the light is located above their head and slightly to the left. Although this observation has fascinated scientists and artists for a long time, the neural basis of this “light from above left” preference for the interpretation of 3D shape remains largely unexplored. Combining behavioral and functional MRI measurements coupled with multivoxel pattern analysis, we show that activations in early visual areas predict best the light source direction irrespective of the perceived shape, but activations in higher occipitotemporal and parietal areas predict better the perceived 3D shape irrespective of the light direction. These findings demonstrate that illumination is processed earlier than the representation of 3D shape in the visual system. In contrast to previous suggestions, we propose that prior knowledge about illumination is processed in a bottom-up manner and influences the interpretation of 3D structure at higher stages of processing.     

Maternal toxicity with continuous nevirapine in pregnancy: results from PACTG 1022

OBJECTIVE: To compare the safety of nelfinavir and nevirapine-based antiretroviral treatment in HIV-1-infected pregnant women. METHODS: In Pediatric AIDS Clinical Trials Group Protocol 1022, 38 antiretroviral-naive pregnant women at 10-30 weeks' gestation were randomized to nelfinavir or nevirapine with zidovudine plus lamivudine. The study was suspended because of greater than expected toxicity and changes in nevirapine prescribing information. The incidence of treatment-limiting hepatic or cutaneous toxicity was compared between groups for all subjects and for the subset with CD4 cell counts greater than 250 cells/microL at study entry. RESULTS: Toxicity was seen in 1 (5%) of 21 subjects randomized to nelfinavir and 5 (29%) of 17 subjects randomized to nevirapine (P = 0.07). Within the nevirapine group, 1 subject developed fulminant hepatic failure and died, and another developed Stevens-Johnson syndrome. The one adverse event associated with nelfinavir occurred in a subject with a CD4 cell count less than 250 cells/microL. All 5 events among subjects with a CD4 cell count greater than 250 cells/microL were associated with nevirapine (P = 0.04). CONCLUSIONS: Continuous nevirapine may be associated with increased toxicity among HIV-1-infected pregnant women with CD4 cell counts greater than 250 cells/microL, as has been observed in non-pregnant women.     

CHOP‐mediated hepcidin suppression modulates hepatic iron load

The liver is the central regulator of iron metabolism and accordingly, chronic liver diseases often lead to systemic iron overload due to diminished expression of the iron‐regulatory hormone hepcidin. To study the largely unknown regulation of iron metabolism in the context of hepatic disease, we used two established models of chronic liver injury, ie repeated carbon tetrachloride (CCl₄) or thioacetamide (TAA) injections. To determine the impact of CCAAT/enhancer‐binding protein (C/EBP)‐homologous protein (CHOP) on hepcidin production, the effect of a single TAA injection was determined in wild‐type and CHOP knockout mice. Furthermore, CHOP and hepcidin expression was assessed in control subjects and patients with alcoholic liver disease. Both chronic injury models developed a distinct iron overload in macrophages. TAA‐, but not CCl₄‐ injected mice displayed additional iron accumulation in hepatocytes, resulting in a significant hepatic and systemic iron overload which was due to suppressed hepcidin levels. C/EBPα signalling, a known hepcidin inducer, was markedly inhibited in TAA mice, due to lower C/EBPα levels and overexpression of CHOP, a C/EBPα inhibitor. A single TAA injection resulted in a long‐lasting (> 6 days) suppression of hepcidin levels and CHOP knockouts (compared to wild‐types) displayed significantly attenuated hepcidin down‐regulation in response to acute TAA administration. CHOP mRNA levels increased 5‐fold in alcoholic liver disease patients versus controls (p < 0.005) and negatively correlated with hepcidin expression. Our results establish CHOP as an important regulator of hepatic hepcidin expression in chronic liver disease. The differences in iron metabolism between the two widely used fibrosis models likely reflect the differential regulation of hepcidin expression in human liver disease. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.