Genomic analysis of antibiotic resistance for Acinetobacter baumannii in a critical care center

AimAcinetobacter baumannii is commonly associated with outbreaks and antibiotic‐resistant nosocomial infection. This study aimed to determine the relationship between antibiotic resistance and genotypes of A. baumannii.MethodsA study was undertaken in the critical care center (CCC) of Juntendo University Urayasu Hospital (Urayasu, Japan) between January 2012 and September 2015. Antimicrobial susceptibility tests were carried out according to the Clinical and Laboratory Standards Institute guidelines. All A. baumannii isolates were verified to carry carbapenemase genes and the ISAba1 element using polymerase chain reaction. The genetic relationship of all A. baumannii isolates was determined by pulsed‐field gel electrophoresis and multilocus sequence typing.ResultsDuring the study period, 1634 patients were admitted to the CCC. Acinetobacter baumannii was detected in 43 patients (average age, 58 ± 19 years; 67.4% men). Six patients were determined to be extensively drug‐resistant A. baumannii and 21 patients determined to be multidrug‐resistant A. baumannii. Antimicrobial susceptibility linked genotypes of A. baumannii. Molecular characterization by pulsed‐field gel electrophoresis and multilocus sequence typing showed that closely related clones of A. baumannii had spread in the CCC.ConclusionResistance to antimicrobial drugs was significantly associated with certain A. baumannii genotypic types and molecular types. Thus, we might be able to predict whether the genotype has spread in the CCC or not when the susceptibility is examined, facilitating the appropriate isolation of patients

Morphological Properties of Lyα Emitters at Redshift 4.86 in the Cosmos Field: Clumpy Star Formation or Merger?

We investigate morphological properties of 61 Lyα emitters (LAEs) at z = 4.86 identified in the COSMOS field, based on Hubble Space Telescope Advanced Camera for Surveys (ACS) imaging data in the F814W band. Out of the 61 LAEs, we find the ACS counterparts for 54 LAEs. Eight LAEs show double-component structures with a mean projected separation of 0".63 (~4.0 kpc at z = 4.86). Considering the faintness of these ACS sources, we carefully evaluate their morphological properties, that is, size and ellipticity. While some of them are compact and indistinguishable from the point-spread function (PSF) half-light radius of 0f".07 (~0.45 kpc), the others are clearly larger than the PSF size and spatially extended up to 0".3 (~1.9 kpc). We find that the ACS sources show a positive correlation between ellipticity and size and that the ACS sources with large size and round shape are absent. Our Monte Carlo simulation suggests that the correlation can be explained by (1) the deformation effects via PSF broadening and shot noise or (2) the source blending in which two or more sources with small separation are blended in our ACS image and detected as a single elongated source. Therefore, the 46 single-component LAEs could contain the sources that consist of double (or multiple) components with small spatial separation (i.e., ≾ 0".3 or 1.9 kpc). Further observation with high angular resolution at longer wavelengths (e.g., rest-frame wavelengths of ≳4000 Å) is inevitable to decipher which interpretation is adequate for our LAE sample