Prevalence of plasmid-mediated quinolone resistance determinants in Enterobacteriaceae from Tunisia

AbstractThe spread of plasmid-mediated quinolone resistance determinants (qnr-like determinants, aac(6′)-Ib-cr and qepA genes) was evaluated in a collection of 281 nalidixic acid-resistant enterobacterial isolates recovered between September 2005 and December 2007 at the Sahloul Hospital, Sousse, Tunisia. Sixteen percent of those isolates carried qnr genes encoding the QnrB1, QnrB2, QnrA6 or QnrS1 determinants. Most qnr-positive isolates were extended-spectrum ß-lactamase (ESBL) producers, being predominantly of the CTX-M-15 type, but also of the SHV-28 and SHV-12 types. The qnr genes were located on plasmids with a size in the range 55–150 kb. The qnrB2 gene was associated with sul1-type integron structures and the qnrB1 gene was associated with orf1005, whereas the genetic environment of qnrA6 was unknown. In two isolates, the qnrS1 gene was located downstream of an ISEcl2 element on plasmids that often carried the narrow-spectrum ß-lactamase gene blaLAP-2; qepA and aac(6′)-Ib-cr were not detected. The present study highlights the wide spread of Qnr-like determinants in Tunisia, with an association with the ESBL CTX-M-15 in human clinical isolates

The T7-Related Pseudomonas putida Phage ϕ15 Displays Virion-Associated Biofilm Degradation Properties

Formation of a protected biofilm environment is recognized as one of the major causes of the increasing antibiotic resistance development and emphasizes the need to develop alternative antibacterial strategies, like phage therapy. This study investigates the in vitro degradation of single-species Pseudomonas putida biofilms, PpG1 and RD5PR2, by the novel phage ϕ15, a ‘T7-like virus’ with a virion-associated exopolysaccharide (EPS) depolymerase. Phage ϕ15 forms plaques surrounded by growing opaque halo zones, indicative for EPS degradation, on seven out of 53 P. putida strains. The absence of haloes on infection resistant strains suggests that the EPS probably act as a primary bacterial receptor for phage infection. Independent of bacterial strain or biofilm age, a time and dose dependent response of ϕ15-mediated biofilm degradation was observed with generally a maximum biofilm degradation 8 h after addition of the higher phage doses (104 and 106 pfu) and resistance development after 24 h. Biofilm age, an in vivo very variable parameter, reduced markedly phage-mediated degradation of PpG1 biofilms, while degradation of RD5PR2 biofilms and ϕ15 amplification were unaffected. Killing of the planktonic culture occurred in parallel with but was always more pronounced than biofilm degradation, accentuating the need for evaluating phages for therapeutic purposes in biofilm conditions. EPS degrading activity of recombinantly expressed viral tail spike was confirmed by capsule staining. These data suggests that the addition of high initial titers of specifically selected phages with a proper EPS depolymerase are crucial criteria in the development of phage therapy

The EUPPBench postprocessing benchmark dataset v1.0

Abstract. Statistical Postprocessing of medium-range weather forecasts is an important component of modern forecasting systems. Since the beginning of modern data science, numerous new postprocessing methods have been proposed, complementing an already very diverse field. However, one of the questions that frequently arises when considering different methods in the framework of implementing operational postprocessing is the relative performance of the methods for a given specific task. It is particularly challenging to find or construct a common comprehensive dataset that can be used to perform such comparisons. Here, we introduce the first version of EUPPBench, a dataset of time-aligned forecasts and observations, with the aim to facilitate and standardize this process. This dataset is publicly available at https://github.com/EUPP-benchmark/climetlab-eumetnet-postprocessing-benchmark. We provide examples on how to download and use the data, propose a set of evaluation methods, and perform a first benchmark of several methods for the correction of 2-meter temperature forecasts. </jats:p