A reproducible brain tumour model established from human glioblastoma biopsies

Background: Establishing clinically relevant animal models of glioblastoma multiforme (GBM) remains a challenge, and many commonly used cell line-based models do not recapitulate the invasive growth patterns of patient GBMs. Previously, we have reported the formation of highly invasive tumour xenografts in nude rats from human GBMs. However, implementing tumour models based on primary tissue requires that these models can be sufficiently standardised with consistently high take rates. Methods: In this work, we collected data on growth kinetics from a material of 29 biopsies xenografted in nude rats, and characterised this model with an emphasis on neuropathological and radiological features. Results: The tumour take rate for xenografted GBM biopsies were 96% and remained close to 100% at subsequent passages in vivo, whereas only one of four lower grade tumours engrafted. Average time from transplantation to the onset of symptoms was 125 days ± 11.5 SEM. Histologically, the primary xenografts recapitulated the invasive features of the parent tumours while endothelial cell proliferations and necrosis were mostly absent. After 4-5 in vivo passages, the tumours became more vascular with necrotic areas, but also appeared more circumscribed. MRI typically revealed changes related to tumour growth, several months prior to the onset of symptoms. Conclusions: In vivo passaging of patient GBM biopsies produced tumours representative of the patient tumours, with high take rates and a reproducible disease course. The model provides combinations of angiogenic and invasive phenotypes and represents a good alternative to in vitro propagated cell lines for dissecting mechanisms of brain tumour progression.publishedVersio

Livestock-Associated MRSA CC1 in Norway; Introduction to Pig Farms, Zoonotic Transmission, and Eradication

Farm animals have been identified as an emerging reservoir for transmission of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) to humans. The low incidence of MRSA in humans and farm animals in Norway has led to the implementation of a national strategy of surveillance and control of LA-MRSA aiming to prevent livestock becoming a domestic source of MRSA to humans. In 2015, MRSA clonal complex 1 spa-type t177 was identified in nine Norwegian pig herds in two neighboring counties. An outbreak investigation was undertaken, and measures of control through eradication were imposed. We performed a register-based cohort study including pig herds and MRSA-positive persons in Norway between 2008 and 2016 to investigate the livestock-association of MRSA CC1, the transmission of the outbreak strain to humans before and after control measures, and the effect of control measures imposed. Data from the Norwegian Surveillance System of Communicable Diseases were merged with data collected through outbreak investigations for LA-MRSA, the National Registry and the Norwegian Register for Health Personnel. Whole-genome sequencing was performed on isolates from livestock and humans identified through contact tracing, in addition to t177 and t127 isolates diagnosed in persons in the same counties. It is likely that a farm worker introduced MRSA CC1 to a sow farm, and further transmission to eight fattening pig farms through trade of live pigs confirmed the potential for livestock association of this MRSA type. The outbreak strain formed a distinct phylogenetic cluster which in addition to the pig farms included one sheep herd and five exposed persons. None of the investigated isolates from possible cases without direct contact to the MRSA positive farms were phylogenetically related to the outbreak strain. Moreover, isolates of t177 or t127 from healthcare and community-acquired cases were not closely related to the outbreak cluster. Eradication measures imposed were effective in eliminating MRSA t177 from the positive pig holdings, and the outbreak strain was not detected in the national pig population or in persons from these counties after control measures

Tumour-associated glial host cells display a stem-like phenotype with a distinct gene expression profile and promote growth of GBM xenografts

Background: Little is known about the role of glial host cells in brain tumours. However, supporting stromal cells have been shown to foster tumour growth in other cancers. Methods: We isolated stromal cells from patient-derived glioblastoma (GBM) xenografts established in GFP-NOD/scid mice. With simultaneous removal of CD11b+ immune and CD31+ endothelial cells by fluorescence activated cell sorting (FACS), we obtained a population of tumour-associated glial cells, TAGs, expressing markers of terminally differentiaed glial cell types or glial progenitors. This cell population was subsequently characterised using gene expression analyses and immunocytochemistry. Furthermore, sphere formation was assessed in vitro and their glioma growth-promoting ability was examined in vivo. Finally, the expression of TAG related markers was validated in human GBMs. Results: TAGs were highly enriched for the expression of glial cell proteins including GFAP and myelin basic protein (MBP), and immature markers such as Nestin and O4. A fraction of TAGs displayed sphere formation in stem cell medium. Moreover, TAGs promoted brain tumour growth in vivo when co-implanted with glioma cells, compared to implanting only glioma cells, or glioma cells and unconditioned glial cells from mice without tumours. Genome-wide microarray analysis of TAGs showed an expression profile distinct from glial cells from healthy mice brains. Notably, TAGs upregulated genes associated with immature cell types and self-renewal, including Pou3f2 and Sox2. In addition, TAGs from highly angiogenic tumours showed upregulation of angiogenic factors, including Vegf and Angiopoietin 2. Immunohistochemistry of three GBMs, two patient biopsies and one GBM xenograft, confirmed that the expression of these genes was mainly confined to TAGs in the tumour bed. Furthermore, their expression profiles displayed a significant overlap with gene clusters defining prognostic subclasses of human GBMs. Conclusions: Our data demonstrate that glial host cells in brain tumours are functionally distinct from glial cells of healthy mice brains. Furthermore, TAGs display a gene expression profile with enrichment for genes related to stem cells, immature cell types and developmental processes. Future studies are needed to delineate the biological mechanisms regulating the brain tumour-host interplay.publishedVersio

Increasing Incidences and Clonal Diversity of Methicillin-Resistant Staphylococcus aureus in the Nordic Countries-Results From the Nordic MRSA Surveillance

Methicillin-resistant Staphylococcus aureus (MRSA) is notifiable in Denmark, Finland, Iceland, Norway and Sweden. The prevalence of MRSA in this region has been low for many years, but all five countries experience increasing numbers of new cases. The aim of the study was to describe the molecular epidemiology in the Nordic countries 2009-2016. Numbers of new cases of MRSA from 1997 to 2016 were compared, and a database containing information on spa-type and place of residence or acquisition, for all new MRSA isolates from 2009 to 2016 was established. A website was developed to visualize the geographic distribution of the spa-types. The incidence of new MRSA cases increased in all Nordic countries with Denmark having 61.8 new cases per 100,000 inhabitants in 2016 as the highest. The number of new cases 2009 to 2016 was 60,984. spa-typing revealed a high genetic diversity, with a total of 2,344 different spa-types identified. The majority of these spa-types (N = 2,017) were found in 1-10 cases. The most common spa-types t127/CC1, t223/CC22, and t304/CC6:8 increased significantly in all Nordic countries during the study period, except for Iceland, while spa-type t002/CC5 decreased in the same four countries. The trends of other common spa-types were different in each of the Nordic countries. The Nordic countries were shown to share similar trends but also to have country-specific characteristics in their MRSA populations. A continued increasing numbers of MRSA will challenge the surveillance economically. A more selected molecular surveillance will probably have to be employed in the future

A reproducible brain tumour model established from human glioblastoma biopsies

<p>Abstract</p> <p>Background</p> <p>Establishing clinically relevant animal models of glioblastoma multiforme (GBM) remains a challenge, and many commonly used cell line-based models do not recapitulate the invasive growth patterns of patient GBMs. Previously, we have reported the formation of highly invasive tumour xenografts in nude rats from human GBMs. However, implementing tumour models based on primary tissue requires that these models can be sufficiently standardised with consistently high take rates.</p> <p>Methods</p> <p>In this work, we collected data on growth kinetics from a material of 29 biopsies xenografted in nude rats, and characterised this model with an emphasis on neuropathological and radiological features.</p> <p>Results</p> <p>The tumour take rate for xenografted GBM biopsies were 96% and remained close to 100% at subsequent passages <it>in vivo</it>, whereas only one of four lower grade tumours engrafted. Average time from transplantation to the onset of symptoms was 125 days ± 11.5 SEM. Histologically, the primary xenografts recapitulated the invasive features of the parent tumours while endothelial cell proliferations and necrosis were mostly absent. After 4-5 <it>in vivo </it>passages, the tumours became more vascular with necrotic areas, but also appeared more circumscribed. MRI typically revealed changes related to tumour growth, several months prior to the onset of symptoms.</p> <p>Conclusions</p> <p><it>In vivo </it>passaging of patient GBM biopsies produced tumours representative of the patient tumours, with high take rates and a reproducible disease course. The model provides combinations of angiogenic and invasive phenotypes and represents a good alternative to <it>in vitro </it>propagated cell lines for dissecting mechanisms of brain tumour progression.</p

MRSA surveillance programmes worldwide : moving towards a harmonised international approach

Multinational surveillance programmes for methicillin-resistant Staphylococcus aureus (MRSA) are dependent on national structures for data collection. This study aimed to capture the diversity of national MRSA surveillance programmes and to propose a framework for harmonisation of MRSA surveillance. The International Society of Antimicrobial Chemotherapy (ISAC) MRSA Working Group conducted a structured survey on MRSA surveillance programmes and organised a webinar to discuss the programmes’ strengths and challenges as well as guidelines for harmonisation. Completed surveys represented 24 MRSA surveillance programmes in 16 countries. Several countries reported separate epidemiological and microbiological surveillance. Informing clinicians and national policy-makers were the most common purposes of surveillance. Surveillance of bloodstream infections (BSIs) was present in all programmes. Other invasive infections were often included. Three countries reported active surveillance of MRSA carriage. Method- ology and reporting of antimicrobial susceptibility, virulence factors, molecular genotyping and epidemiological metadata varied greatly. Current MRSA surveillance programmes rely upon heterogeneous data collection systems, which hampers international epidemiological monitoring and research. To harmonise MRSA surveillance, we suggest improving the integration of microbiological and epidemiological data, implementation of central biobanks for MRSA isolate collection, and inclusion of a representative sample of skin and soft-tissue infection cases in addition to all BSI cases.peer-reviewe

The fight to keep resistance at bay, epidemiology of carbapenemase producing organisms (CPOs), vancomycin resistant enterococci (VRE) and methicillin resistant Staphylococcus aureus (MRSA) in Norway, 2006-2017

Introduction: Scandinavian countries have traditionally had a low prevalence of resistant organisms, but have in recent years experienced a change in their epidemiology. We aim to describe the epidemiology of carbapenemase-producing organisms (CPOs), vancomycin-resistant enterococci (VRE) and methicillin-resistant S. aureus (MRSA) in Norway, measure the importance of infections contracted abroad, and assess the morbidity and mortality associated with these resistant bacteria in Norway. Methods and materials: We used data from the Norwegian surveillance system for communicable diseases covering all findings of the selected resistant bacteria including both infections and colonisation, in the period 2006–2017. Annual trends were assessed using negative binomial regression. For MRSA, we were able to calculate the Morisita-Horn index and transmission numbers following importation in order to assess the effect this had on further domestic transmission. Results: The incidence rates (per 100,000 personyears) of the three groups of resistant bacteria have increased during the period. In 2017 the incidence rates were 0.82 for CPOs, 7.09 for VRE and 43.8 for MRSA. 81% of CPO cases were diagnosed in hospitals, but 73% were infected abroad. Most VRE cases were infected in Norwegian hospitals, 85% were associated with hospitals outbreaks. MRSA was predominantly diagnosed in the community, only 21% were diagnosed in hospitals. Of all MRSA cases, 35% were infected in other countries. Most MRSA spa-types were not identified again after introduction, resulting in a transmission of MRSA equivalent to a mean of 0.30 persons infected from each spa-type identified (range: 0–22). The proportion of infections among all notified cases within each diagnose was 44% for MRSA, 9% for VRE and 45% for CPOs. Among persons notified with bacteraemia, the 30 days all-cause mortality were 20%, 16% and 50% for MRSA, VRE and CPOs respectively. Discussion: The incidence rates of CPOs, VRE and MRSA in Norway are low, but increasing. The continuing increase of notified resistant bacteria highlights the need for a revision of existing infection prevention and control guidelines

The fight to keep resistance at bay, epidemiology of carbapenemase producing organisms (CPOs), vancomycin resistant enterococci (VRE) and methicillin resistant Staphylococcus aureus (MRSA) in Norway, 2006-2017

Introduction - Scandinavian countries have traditionally had a low prevalence of resistant organisms, but have in recent years experienced a change in their epidemiology. We aim to describe the epidemiology of carbapenemase-producing organisms (CPOs), vancomycin-resistant enterococci (VRE) and methicillin-resistant S. aureus (MRSA) in Norway, measure the importance of infections contracted abroad, and assess the morbidity and mortality associated with these resistant bacteria in Norway. Methods and materials - We used data from the Norwegian surveillance system for communicable diseases covering all findings of the selected resistant bacteria including both infections and colonisation, in the period 2006–2017. Annual trends were assessed using negative binomial regression. For MRSA, we were able to calculate the Morisita-Horn index and transmission numbers following importation in order to assess the effect this had on further domestic transmission. Results - The incidence rates (per 100,000 personyears) of the three groups of resistant bacteria have increased during the period. In 2017 the incidence rates were 0.82 for CPOs, 7.09 for VRE and 43.8 for MRSA. 81% of CPO cases were diagnosed in hospitals, but 73% were infected abroad. Most VRE cases were infected in Norwegian hospitals, 85% were associated with hospitals outbreaks. MRSA was predominantly diagnosed in the community, only 21% were diagnosed in hospitals. Of all MRSA cases, 35% were infected in other countries. Most MRSA spa-types were not identified again after introduction, resulting in a transmission of MRSA equivalent to a mean of 0.30 persons infected from each spa-type identified (range: 0–22). The proportion of infections among all notified cases within each diagnose was 44% for MRSA, 9% for VRE and 45% for CPOs. Among persons notified with bacteraemia, the 30 days all-cause mortality were 20%, 16% and 50% for MRSA, VRE and CPOs respectively. Discussion - The incidence rates of CPOs, VRE and MRSA in Norway are low, but increasing. The continuing increase of notified resistant bacteria highlights the need for a revision of existing infection prevention and control guidelines

Fysioterapi ved Bekhterev sykdom i Trondheim og omkringliggende kommuner

In this study we investigated the use of physiotherapy services and exercise facilities by patients with Ankylosing Spondylitis in Trondheim and three surrounding counties. Patient satisfaction with regard to the services was also recorded. Associations between patient characteristics and the use of physiotherapy were investigated. The aim was to assess the adequacy of the services and facilities offered and to get knowledge of characteristics associated with the use of physiotherapy services. Totally 220 of 410 patients (57 percent) answered a mailed questionnaire about access to and use of physiotherapy services and exercise facilities including questions regarding disease activity (The Bath Ankylosing Spondylitis Disease Activity Index, BASDAI), physical functioning (The Bath Ankylosing Spondylitis Functional Index, BASFI) and burden of disease (BAS-G). The results indicate that 61 percent of the patients had received physiotherapy treatments during the last year, and those who were most affected with regard to disease activity, physical functioning and burden of disease had received more treatments. Pain had the biggest impact on the amount of physiotherapy services received whereas age, residence-county and gender had no influence. Around one third of the patients used exercise facilities outside the regular health care system, while 60 percent stated that the services corresponded well to their needs. The percentage that was satisfied varied between 87 and 100 with the different services. About one third of the patients desired extended physiotherapy services beyond normal working hours