Investigation of Commensal Escherichia coli Populations of Cormorant Hatchlings in the Absence of Anthropogenic Impacts in Remote Areas of West Mongolia

To increase our understanding of bacterial intestinal colonization in animal populations lacking substantial anthropogenic influence we studied the diversity of E. coli in cormorants from the pristine West-Mongolian steppe. E. coli were isolated from individual birds of two cormorant colonies located on small islands in lakes at least 100 km away from human settlements. Diversity of the isolates was studied using pulsed-field gel electrophoresis (PFGE). 137 isolates of cormorant colony-1 and 75 isolates of cormorant colony-2 resulted in 60 and 33 PFGE types, respectively. Representative strains of each PFGE type were analyzed via PCR in terms of phylogroups and extraintestinal virulence-associated genes (exVAGs). Bacterial adhesion to the chicken intestinal cell line CHIC-8E11 and antimicrobial resistance was also determined. Most isolates belonged to phylogroup B1 (68.3%) followed by B2 and E with B2 harboring the highest total number of exVAGs per isolate. Unexpectedly, a PFGE type with relatively few exVAGs displayed the highest isolation frequency, also showing a high adhesion rate. Comparative analysis of exVAGs to other E. coli populations of wildlife origin revealed that the secreted autotransporter toxin encoding sat gene was only present in cormorants. Overall, E. coli in cormorants maintained a high diversity under minimal anthropogenic influences, which likely enables intestinal colonization

Fluoxetine normalizes disrupted light-induced entrainment, fragmented ultradian rhythms and altered hippocampal clock gene expression in an animal model of high trait anxiety- and depression-related behavior

<p><b>Introduction</b> Disturbances of circadian rhythms are a key symptom of mood and anxiety disorders. Selective serotonin reuptake inhibitors (SSRIs) - commonly used antidepressant drugs – also modulate aspects of circadian rhythmicity. However, their potential to restore circadian disturbances in depression remains to be investigated.</p> <p><b>Materials and methods</b> The effects of the SSRI fluoxetine on genetically based, depression-related circadian disruptions at the behavioral and molecular level were examined using mice selectively bred for high anxiety-related and co-segregating depression-like behavior (HAB) and normal anxiety/depression behavior mice (NAB).</p> <p><b>Results</b> The length of the circadian period was increased in fluoxetine-treated HAB as compared to NAB mice while the number of activity bouts and light-induced entrainment were comparable. No difference in hippocampal <i>Cry2</i> expression, previously reported to be dysbalanced in untreated HAB mice, was observed, while <i>Per2</i> and <i>Per3</i> mRNA levels were higher in HAB mice under fluoxetine treatment.</p> <p><b>Discussion</b> The present findings provide evidence that fluoxetine treatment normalizes disrupted circadian locomotor activity and clock gene expression in a genetic mouse model of high trait anxiety and depression. An interaction between the molecular mechanisms mediating the antidepressant response to fluoxetine and the endogenous regulation of circadian rhythms in genetically based mood and anxiety disorders is proposed.</p

Extensively drug-resistant Klebsiella pneumoniae ST307 outbreak, north-eastern Germany, June to October 2019

From June to October 2019, 17 patients (six infected, 11 colonised) with an extensively drug-resistant (XDR) Klebsiella pneumoniae strain were notified from four Western Pomerania medical facilities. The XDR K. pneumoniae produced carbapenemases NDM-1 and OXA-48, and was only susceptible to chloramphenicol, tigecycline and cefiderocol. Synergistic activity was observed for the combination of aztreonam plus ceftazidime-avibactam. Genomic analyses showed all isolates belonged to K. pneumoniae sequence type 307. Control measures and further investigations are ongoing.Peer Reviewe

Detection and characterization of putative hypervirulent Klebsiella pneumoniae isolates in microbiological diagnostics

Abstract Hypervirulent Klebsiella pneumoniae strains (hvKp) can cause invasive community-acquired infections in healthy patients of all ages. In this study, the prevalence of putative hvKp in a German tertiary center was investigated and hvKp were characterized by phenotypic and molecular assays. All K. pneumoniae isolates in routine microbiological diagnostics from a single center were screened by string-testing over a period of 6 months. String-test positive (≥ 0.5 mm) isolates were re-evaluated on different media and under various conditions (aerobe, anaerobe). For string-test positive isolates, genes (magA, iutA, rmpA and rmpA2) associated with hypermucoviscosity and hypervirulence were amplified by multiplex PCR. PCR-positive isolates were subjected to whole-genome sequencing and sedimentation and biofilm formation assays. From 1310 screened K. pneumoniae isolates in clinical routine 100 isolates (7.6%) were string test positive. From these, 9% (n = 9) were defined as putative hvKp (string-test+/PCR+). Highest rate of string-test-positive isolates was observed on MacConkey agar under aerobic conditions. Amongst these nine putative hvKp isolates, the international lineage ST23 carrying hvKp-plasmid pKpVP-1 was the most common, but also a rare ST86 with pKpVP-2 was identified. All nine isolates showed hypermucoviscosity and weak biofilm formation. In conclusion, 9% of string-positive, respectively 0.69% of all K. pneumoniae isolates from routine were defined as putative hypervirulent. MacConkey agar was the best medium for hvKp screening