Persistence and Diffusion of mecC-Positive CC130 MRSA Isolates in Dairy Farms in Meurthe-et-Moselle County (France)

Background: Methicillin resistance in Staphylococcus aureus (MRSA) is classically conferred by the acquisition of the mecA gene encoding an additional penicillin binding protein with low affinity for beta-lactams. A mecA variant, named mecC, was described in 2011. MRSA isolates harboring mecC of both animal and human origin have since been collected in different European countries. In France, animal cases were reported in 4 dairy farms between 2008 and 2013 in the Meurthe-et-Moselle county, all located in a 30 km perimeter, suggesting a possible dissemination of mecC-positive MRSA strains. We performed a prospective study to evaluate the local epidemiology of such strains in terms of (i) dissemination among animals, humans and in the environment, and (ii) persistence in Meurthe-et-Moselle dairy cattle farms.Methods: The 4 French dairy farms with previous reports of mecC-positive MRSA strains and 14 farms in the same perimeter were included in this study. In each farm, nasal swabs, rectal swabs and milk samples were collected from 10 randomly selected cows, as well as nasal samples from family pets, volunteer farmers and veterinarians. One farm (E0), in which mecC-MRSA isolates were detected, was selected to study more deeply the dissemination of mecC-positive strains within the farm. After pre-enrichment of swabs and milk, they were subcultured on MSSA/MRSA chromogenic selective agar plates. S. aureus colonies were tested with a multiplex PCR to detect the mecA and mecC genes. The mecC-positive strains were characterized using DNA microarray.Results:mecC-positive strains were recovered in four farms, corresponding to the ones with previous reports of mecC-positive MRSA strains, and originated only from dairy cow samples. The screening in the E0 farm showed that 22% of the dairy cows carried mecC-positive MRSA. Three strains were also isolated from the environmental samples. All mecC-positive strains belonged to the clonal complex CC130 and harbored the same spa-type t1736.Conclusion: This study found that mecC-positive MRSA isolates are able to persist within the same farms for several years after being introduced in this setting and are able to widely disseminate but only among dairy cows suggesting that milking machines might be a key player

The LOFAR pilot surveys for pulsars and fast radio transients

We have conducted two pilot surveys for radio pulsars and fast transients with the Low-Frequency Array (LOFAR) around 140 MHz and here report on the first low-frequency fast-radio burst limit and the discovery of two new pulsars. The first survey, the LOFAR Pilot Pulsar Survey (LPPS), observed a large fraction of the northern sky, ~1.4 x 10^4 sq. deg, with 1-hr dwell times. Each observation covered ~75 sq. deg using 7 independent fields formed by incoherently summing the high-band antenna fields. The second pilot survey, the LOFAR Tied-Array Survey (LOTAS), spanned ~600 sq. deg, with roughly a 5-fold increase in sensitivity compared with LPPS. Using a coherent sum of the 6 LOFAR "Superterp" stations, we formed 19 tied-array beams, together covering 4 sq. deg per pointing. From LPPS we derive a limit on the occurrence, at 142 MHz, of dispersed radio bursts of 107 Jy for the narrowest searched burst duration of 0.66 ms. In LPPS, we re-detected 65 previously known pulsars. LOTAS discovered two pulsars, the first with LOFAR or any digital aperture array. LOTAS also re-detected 27 previously known pulsars. These pilot studies show that LOFAR can efficiently carry out all-sky surveys for pulsars and fast transients, and they set the stage for further surveying efforts using LOFAR and the planned low-frequency component of the Square Kilometer Array.Comment: 18 pages, 10 figures, accepted for A&

Clinical value of the antibiofilmograma and contribution of biofilm formation capacity for the management of bone and joint infections due to staphylococcus

Dans le cadre d'infections ostéo-articulaire (IOA), l'utilisation de matériels étrangers peut, en cas de contamination, aboutir à la formation d'un biofilm associé à un risque plus important d'échec du traitement et de récidive. Les bactéries sous forme de biofilm sont en effet protégées de l'action du système immunitaire et ont une tolérance plus importante aux antibiotiques. A l'heure actuelle, l'activité des antibiotiques est déterminée par la CMI (Concentration Minimale Inhibitrice), mais cette valeur ne tient pas compte de la forme sessile des bactéries. C'est pourquoi, la société BioFilm Control a développé un nouveau test, l'Antibiofilmogramme®, permettant de déterminer la CMI biofilm (CMIb) reflétant la capacité préventive des antibiotiques sur l'installation des microorganismes en biofilm. L'objectif de ma thèse a été dans un premier temps de participer à la démonstration de la valeur clinique de ce nouveau test dans le cadre des IOA à Staphylococcus aureus. Nous avons pu mettre en place un recueil prospectif et réaliser les premiers essais in vitro. Nos résultats obtenus pour la cloxacillin ont pu par la suite être confirmés sur un modèle in vivo d'infection sur matériel. Dans un second temps, nous avons pu caractériser la capacité de formation de biofilm des souches cliniques en fonction des profils de résistance obtenus en Antibiofilmogramme®. Nous avons pu mettre en évidence des profils différents liés à la clonalité des souches. Enfin, nous avons pu mettre au point une nouvelle méthode de rinçage et de quantification des biofilms pour les modèles en microplaque via l'utilisation de vapeur. Cette approche simple améliore grandement la reproductibilité des résultats et préserve l'intégrité structurelle des biofilmsIn the context of Bone and Joint Infections (BJIs), the orthopedic devices are preferential surface for microorganisms to adhere and form biofilm associated with high rates of failures and relapses. Within biofilm, bacteria are protected from the host immune response and are able to survive in the presence of high concentration of antibiotics. The standard Minimal Inhibitory Concentration (MIC) informs on the antibiotic susceptibility of planktonic bacteria, but is not suited for biofilm. The company BioFilm Control developed a new test named Antibiofilmogram® which measures early-stage biofilm growth in presence of antibiotics, and provides a biofilm Minimal Inhibitory Concentration (bMIC). The aim of my PhD research was first to take part in the demonstration of the clinical value of this new test for Staphylococcus aureus BJIs. We established a prospective collection of data and strains and realized the first in vitro assays. Our results for cloxacillin were confirmed in an in vivo model of catheter-associated infection. Second, we characterized the biofilm formation capacity of various clinical isolates based on the Antibiofilmogram® resistance profile. We showed that the biofilm formation capacity is correlated with clonal lineage. Finally, we were able to develop a new method of washing and quantifying biofilms for microplate system using steam. This simple approach preserves the biofilm integrity and lead to highly reproducible dat

Apport de l'antibiofilmogramme et de la mesure de la capacité de formation du biofilm dans la prise en charge des infections ostéo-articulaires à staphylocoques

In the context of Bone and Joint Infections (BJIs), the orthopedic devices are preferential surface for microorganisms to adhere and form biofilm associated with high rates of failures and relapses. Within biofilm, bacteria are protected from the host immune response and are able to survive in the presence of high concentration of antibiotics. The standard Minimal Inhibitory Concentration (MIC) informs on the antibiotic susceptibility of planktonic bacteria, but is not suited for biofilm. The company BioFilm Control developed a new test named Antibiofilmogram® which measures early-stage biofilm growth in presence of antibiotics, and provides a biofilm Minimal Inhibitory Concentration (bMIC). The aim of my PhD research was first to take part in the demonstration of the clinical value of this new test for Staphylococcus aureus BJIs. We established a prospective collection of data and strains and realized the first in vitro assays. Our results for cloxacillin were confirmed in an in vivo model of catheter-associated infection. Second, we characterized the biofilm formation capacity of various clinical isolates based on the Antibiofilmogram® resistance profile. We showed that the biofilm formation capacity is correlated with clonal lineage. Finally, we were able to develop a new method of washing and quantifying biofilms for microplate system using steam. This simple approach preserves the biofilm integrity and lead to highly reproducible dataDans le cadre d'infections ostéo-articulaire (IOA), l'utilisation de matériels étrangers peut, en cas de contamination, aboutir à la formation d'un biofilm associé à un risque plus important d'échec du traitement et de récidive. Les bactéries sous forme de biofilm sont en effet protégées de l'action du système immunitaire et ont une tolérance plus importante aux antibiotiques. A l'heure actuelle, l'activité des antibiotiques est déterminée par la CMI (Concentration Minimale Inhibitrice), mais cette valeur ne tient pas compte de la forme sessile des bactéries. C'est pourquoi, la société BioFilm Control a développé un nouveau test, l'Antibiofilmogramme®, permettant de déterminer la CMI biofilm (CMIb) reflétant la capacité préventive des antibiotiques sur l'installation des microorganismes en biofilm. L'objectif de ma thèse a été dans un premier temps de participer à la démonstration de la valeur clinique de ce nouveau test dans le cadre des IOA à Staphylococcus aureus. Nous avons pu mettre en place un recueil prospectif et réaliser les premiers essais in vitro. Nos résultats obtenus pour la cloxacillin ont pu par la suite être confirmés sur un modèle in vivo d'infection sur matériel. Dans un second temps, nous avons pu caractériser la capacité de formation de biofilm des souches cliniques en fonction des profils de résistance obtenus en Antibiofilmogramme®. Nous avons pu mettre en évidence des profils différents liés à la clonalité des souches. Enfin, nous avons pu mettre au point une nouvelle méthode de rinçage et de quantification des biofilms pour les modèles en microplaque via l'utilisation de vapeur. Cette approche simple améliore grandement la reproductibilité des résultats et préserve l'intégrité structurelle des biofilm

Our House, in the Middle of Our Tweets

Twitter, Flickr, Instagram, and other public social media sites have inspired lots of analysis of public geotagged posts. In order to understand these posts, it is important to know where their authors live. Based on a study of 195 prolific Twitter users in the Pittsburgh area, and their ground truth home locations, we show that simple algorithms can find about 80% of people’s home addresses within 1 kilometer. We show why this is near the upper bound of feasibility, show that studying as few as 10 tweets can achieve almost the same results, and discuss implications for future social media analyses

Generating Neighborhood Guides from Social Media

What are the neighborhoods in this city like? This is a question that movers and travelers ask all the time, and despite the information sources on the internet, there are few neighborhood guides to help people answer it. We describe formative research, including the Twitter Neighborhood TF-IDF map and an interview-based study of 17 recent movers and travelers. Based on this research, we then describe plans for construction of neighborhood guides based on social media posts in each neighborhood and publicly available data

Using Social Media Data to Understand Cities

Understanding urban dynamics is crucial for a number of domains, but it can be expensive and time consuming to gather necessary data. The rapid rise of social media has given us a new and massive source of geotagged data that can be transformative in terms of how we understand our cities. In this position paper, we describe three opportunities in using geotagged social media data: to help city planners, to help small businesses, and to help individuals adapt to their city better. We also sketch some possible research projects to help map out the design space, as well as discuss some limitations and challenges in using this kind of data.</p

State of the Geotags: Motivations and Recent Changes

The widespread adoption of smartphones has made it possible for large numbers of people to geotag their social media posts. Past work has studied the reasons people tag their location and the ways they do so on location-based social networks like Foursquare. But it is unclear how well these findings generalize to other social media not centered on location, such as Twitter or Flickr. Through an analysis of public data and two surveys, we investigate why people geotag their photos, tweets, and other non-location-based social media. We found that their reasons are similar to those in location-based social networks. We also found several surprises due to the different nature of these platforms and the changes since location-based social networks were introduced. For example, people usually consciously geotag, though a significant portion geotags unintentionally; coordinate geotagging is changing to placetagging; and job-posting bots constitute a growing portion of public geotags

A steam-based method to investigate biofilm

Abstract Biofilm has become a major topic of interest in medical, food, industrial, and environmental bacteriology. To be relevant, investigation of biofilm behavior requires effective and reliable techniques. We present herein a simple and robust method, adapted from the microplate technique, in which steam is used as a soft washing method to preserve biofilm integrity and to improve reproducibility of biofilm quantification. The kinetics of steam washing indicated that the method is adapted to remove both planktonic bacteria and excess crystal violet (CV) staining for S. aureus, S. epidermidis, S. carnosus, P. aeruginosa, and E. coli biofilm. Confocal laser scanning microscopy confirmed that steam washing preserved the integrity of the biofilm better than pipette-based washing. We also investigated the measurement of the turbidity of biofilm resuspended in phosphate-buffered saline (PBS) as an alternative to staining with CV. This approach allows the discrimination of biofilm producer strains from non-biofilm producer strains in a way similar to CV staining, and subsequently permits quantification of viable bacteria present in biofilm by culture enumeration from the same well. Biofilm quantification using steam washing and PBS turbidity reduced the technical time needed, and data were highly reproducible

Methicillin-resistant Staphylococcus aureus in the environment of public transport: data from the metropolitan network in Lyon, France

International audienceMethicillin-resistant Staphylococcus aureus (MRSA) is involved in community-acquired and nosocomial diseases. The means of MRSA transmission and dissemination in the community remain uncertain. Studies have shown that public transport systems could be a source of MRSA and may serve as a potential source for community-acquired MRSA infections. This study aimed to investigate MRSA contamination on Lyon's metropolitan network (Métro) in France. Hand-touched surfaces were sampled with sterile swabs (Transystem(\textregistered)) during a 1-day transversal study by collecting 50 samples in seven hub stations and two trains for each of the four Métro lines. Then, during a longitudinal study, one sample was collected twice daily for 30 consecutive days in the busiest and most congested hub station. All swabs were incubated in enrichment medium for 24 h and then each suspension was plated onto a chromogenic selective medium for MRSA. After 24 h at 36 °C, all presumptive MRSA colonies were tested using VITEK(\textregistered) MS to confirm identification as S. aureus as well as by Alere\texttrademark PBP2a Culture Colony Test and mecA/mecC PCR to check methicillin resistance. Of the 110 swabs tested, 24 presumptive MRSA colonies were isolated, of which 2 were confirmed as S. aureus by VITEK(\textregistered) MS. These two isolates were tested negative using the PBP2a Culture Colony Test and PCR. Unlike other foreign cities such as Lisbon, the current data suggest a low level of MRSA contamination of hand-touched surfaces on Lyon's Métro. This should be put in perspective with the low level of MRSA colonisation in the French community