Masses of high-redshift clusters via SZ effect observations

Journal ArticleWe present Sunyaev-Zel'dovich Effect (SZE) observations of distant, highly X-ray luminous clusters of galaxies. We use the SZE data to constrain their total masses, independent of X-ray observations. To do this, we assume the clusters have the same gas mass fraction as that derived from SZE measurements of a sample of known massive clusters, and then infer each cluster's mass from its SZE data. In the systems with published X-ray temperatures, we find good agreement between our SZE-derived temperatures and those inferred from X-ray spectroscopy; in the system without X-ray derived temperatures, the SZE data provide the first confirmation that it is indeed a massive system. The abundance of clusters at high redshift is critically sensitive to the values of the cosmological parameters and so the demonstrated ability to determine cluster temperatures and masses from SZE observations independent of X-ray data illustrates the power of using deep SZE surveys to probe the distant universe

Oxazolidinone resistance-associated genes cfr and optrA in MDR CoNS from healthy pigs in Italy

BACKGROUND: Oxazolidinones are relatively novel antibiotics used exclusively in human medicine as last resort drugs for resistant pathogens like MRSA, vancomycin-resistant enterococci and penicillin-resistant Streptococcus pneumoniae. However, in the last two decades, oxazolidinone resistance genes cfr and optrA have been sporadically reported worldwide in Staphylococcus spp. of livestock origin.(1) These genes can be chromosomal, but they are often transferable through mobile genetic elements, especially plasmids.(2) In Italy, they have been recently detected in enterococci of swine origin.(3) OBJECTIVES: To uncover the presence of cfr and optrA genes in methicillin-resistant CoNS (MRCoNS) originating from swine nasal swabs sampled in a high farm-density area of northwestern Italy. Healthy pigs were sampled from three productive stages (finishing, weaners and sows). After isolating pure cultures, selected staphylococci (n = 27), resulted methicillin-resistant from previous mecA identification, were phenotypically tested through Kirby–Bauer disc diffusion method for the antibiotics clindamycin, doxycycline, erythromycin, enrofloxacin, florfenicol, gentamicin, linezolid, tetracycline, tiamulin and trimethoprim/sulfamethoxazole (EUCAST v.11.0 guidelines for linezolid disc, CLSI VET08 for the other antibiotics). MIC through Etest (Liofilchem®, Roseto degli Abbruzzi, Teramo, Italy) was used for the antibiotic ceftaroline. RESULTS: All the chosen MRCoNS were MDR (MDR CoNS), as they were phenotypically resistant to more than three antibiotic classes. No strain was positive for ceftaroline resistance. Since linezolid resistance was recovered in six samples, we decided to perform PCR for the cfr gene (746 bp), which was detected in Staphylococcus sciuri from a piglet (GenBank accession number OL412394), and optrA (1395 bp), which was recovered in Staphylococcus pasteuri from a finisher, S. sciuri from a sow and Staphylococcus cohnii from a weaner (GenBank accession numbers OM165030, OM165031 and OM165032). Sanger sequencing confirmed PCR result for cfr, with 100% identity with the cfr gene detected from a clinical Italian isolate of MRSA (MH746818), and for optrA gene, which had 100% identity with the optrA previously found in a swine Italian Enterococcus faecium strain (MT723958). As far as we know, this is the first time that a cfr gene has been detected in S. sciuri from a nasal sample of animal origin in Italy. Furthermore, optrA was never detected in S. pasteuri and S. cohnii strains. CONCLUSIONS: These results are relevant from a One Health perspective, as they underline the need for oxazolidinone resistance monitoring, not only in human medicine, but also at farm level. In this way, it will be easier to prevent the dissemination of this resistance to human community and hospitals, where oxazolidinones are considered last-resort antibiotics. Furthermore, they remind the importance of surveillance of antibiotic usage in pigs, as cfr and optrA resistance in staphylococci can be elicited using certain antibiotics, like phenicols, due to cross-resistance to this antibiotic class

Far-Infrared Emission From E and E/S0 Galaxies

Studies of cold material through IRAS 60um and 100um observations indicated that half of ordinary E and E/S0 galaxies were detected above the 3 sigma level, indicating that cold gas is common, although no correlation was found between the optical and far- infrared fluxes. Most detections were near the instrumental threshold, and given an improved understanding of detection confidence, we reconsider the 60um and 100um detection rate. After excluding active galactic nuclei, peculiar systems, and background contamination, only 15 non-peculiar E and E/S0 galaxies from the RSA catalog are detected above the 98% confidence level, about 12% of the sample. An unusually high percentage of these 15 galaxies possess cold gas (HI, CO) and optical emission lines (Halpha), supporting the presence of gas cooler than 10E4 K. The 60um to 100um flux ratios imply a median dust temperature for the sample of 30 K, with a range of 23-38 K. These detections define the upper envelope of the optical to far-infrared relationship, F_fir propto F_B^0.24+/-0.08, showing that optically bright objects are also brighter in the infrared, although with considerable dispersion. A luminosity correlation is present with L_fir propto L_B^1.65+/-0.28, but the dust temperature is uncorrelated with luminosity. Models that contain large dust grains composed of amorphous carbon plus silicates come close to reproducing the typical 60um to 100um flux ratios, the far-infrared luminosity, and the L_fir - L_B relationship.Comment: 10 postscript pages, 2 tables, and 2 figure