Procalcitonin for diagnosis of infection and guide to antibiotic decisions: past, present and future

There are a number of limitations to using conventional diagnostic markers for patients with clinical suspicion of infection. As a consequence, unnecessary and prolonged exposure to antimicrobial agents adversely affect patient outcomes, while inappropriate antibiotic therapy increases antibiotic resistance. A growing body of evidence supports the use of procalcitonin (PCT) to improve diagnosis of bacterial infections and to guide antibiotic therapy. For patients with upper and lower respiratory tract infection, post-operative infections and for severe sepsis patients in the intensive care unit, randomized-controlled trials have shown a benefit of using PCT algorithms to guide decisions about initiation and/or discontinuation of antibiotic therapy. For some other types of infections, observational studies have shown promising first results, but further intervention studies are needed before use of PCT in clinical routine can be recommended. The aim of this review is to summarize the current evidence for PCT in different infections and clinical settings, and discuss the reliability of this marker when used with validated diagnostic algorithms

Fluorescent labelling of Beet necrotic yellow vein virus and Beet soil-borne mosaic virus for co- and superinfection experiments in Nicotiana benthamiana.

Infectious full-length clones of Beet necrotic yellow vein virus (BNYVV) and Beet soil-borne mosaic virus (BSBMV), both genus Benyvirus, were used for fluorescent labelling with the objective to study their interaction in coinfection and superinfection experiments. Fluorescent labelling was achieved by replacing a part of the RNA2 encoded coat protein read-through domain with either GFP or mRFP fluorescent marker proteins. This resulted in a translational fusion comprising the coat and the fluorescent protein. The labelled viruses were infectious and moved systemically in Nicotiana benthamiana, producing wild-type-like symptoms. Virus particles could be observed by electron microscopy, demonstrating that the viral read-through domain is dispensable for particle formation. Coinfection experiments revealed a spatial separation of differentially labelled populations of both identical and different Benyvirus species after N. benthamiana agro-inoculation. Identical observations were obtained when Tobacco rattle virus (TRV) was differentially labelled and used for coinfection. In contrast, coinfections of BSBMV with Potato virus X (PVX) or TRV resulted in many co-infected cells lacking spatial separation. Micro-projectile co-bombardment of N. benthamiana leaves revealed that two differently labelled populations of the same virus co-infected only a few cells before starting to separate. In superinfection experiments with N. benthamiana, BSBMV and BNYVV were unable to establish a secondary infection in plants that were previously infected with BNYVV or BSBMV. Taken together, this is the first work to describe the interaction between two economically important Benyviruses using fluorescence-labelled full-length clones

Identification of the novel class D β-lactamase OXA-679 involved in carbapenem resistance in Acinetobacter calcoaceticus

Objectives: The aim of this study was to characterize the Acinetobacter calcoaceticus clinical isolate AC 2117 with the novel carbapenem-hydrolysing class D β-lactamase (CHDL) OXA-679. Methods: Identification of the species and β-lactamases was verified by genome sequencing (PacBio) and phylogenetic analyses. Antibiotic susceptibility of AC 2117 and transformants harbouring cloned blaOXA-679 was evaluated using antibiotic gradient strips and microbroth dilution. OXA-679 was purified heterologously and kinetic parameters were determined using spectrometry or isothermal titration calorimetry. The impact of OXA-679 production during imipenem therapy was evaluated in the Galleria mellonella infection model. Results: Sequencing of the complete genome of the clinical A. calcoaceticus isolate AC 2117 identified a novel CHDL, termed OXA-679. This enzyme shared sequence similarity of 71% to each of the families OXA-143 and OXA-24/40. Phylogenetic analyses revealed that OXA-679 represents a member of a new OXA family. Cloning and expression of blaOXA-679 as well as measurement of kinetic parameters revealed the effective hydrolysis of carbapenems which resulted in reduced susceptibility to carbapenems in Escherichia coli and A. calcoaceticus, and high-level carbapenem resistance in Acinetobacter baumannii. Infection of larvae of G. mellonella with a sublethal dose of blaOXA-679-expressing A. baumannii could not be cured by high-dose imipenem therapy, indicating carbapenem resistance in vivo. Conclusions: We identified blaOXA-679 in a clinical A. calcoaceticus isolate that represents a member of the new OXA-679 family and that conferred high-level carbapenem resistance in vitro and in vivo

Cognitive behavioural therapy for the treatment of late life depression: study protocol of a multicentre, randomized, observer-blinded, controlled trial (CBTlate)

BackgroundLate-life depression (LLD) is one of the most prevalent mental disorders in old age. It is associated with various adverse outcomes and frequent use of health care services thereby remaining a serious public health concern. Compared with depression in early adulthood, most treatment options of LLD are less effective. Psychotherapy may be particularly beneficial for LLD due to specific psychological conditions in old age and a low risk of side effects. Although cognitive behavioural therapy (CBT) is highly established and effective in depression in young and mid-life there is only a limited number of small studies on CBT in LLD. An LLD-specific CBT has not yet been compared to an active, but unspecific supportive psychological intervention in a multicentre trial.MethodsHere we present the design of the CBTlate trial, which is a multicentre, randomized, observer-blinded, active-controlled, parallel group trial. CBTlate aims at including 248 patients with LLD of both genders at 7 sites in Germany. The purpose of the study is to test the hypothesis that a 15-session individually-delivered CBT specific for LLD is of superior efficacy in reducing symptoms of depression in comparison with a supportive unspecific intervention (SUI) of the same quantity. The intervention includes 8weeks of individual treatment sessions twice per week and a follow-up period of 6months after randomization. The primary end point is the severity of depression at the end of treatment measured by the self-rated 30-item Geriatric Depression Scale (GDS). Secondary endpoints include depressive symptoms at week 5 and at follow-up (6months after randomization). Additional secondary endpoints include the change of depressive symptoms assessed with a clinician-rating-scale and a patient reported outcome instrument for major depressive disorder, anxiety symptoms, sleep, cognition, quality of life, and overall health status from baseline to end-of treatment and to end of follow-up. Add-on protocols include MRI and the collection of blood samples.DiscussionThis study is the first multicentre trial of a specific CBT intervention for LLD compared to an unspecific supportive psychological intervention administered in a specialist setting. It has important implications for developing and implementing efficient psychotherapeutic strategies for LLD and may be a significant step to broaden treatment options for people suffering from LLD.Trial registrationClinicalTrials.gov (NCT03735576, registered on 24 October 2018); DRKS (DRKS00013769, registered on 28 June 2018)