Emergence of daptomycin resistance in daptomycin-naïve rabbits with methicillin-resistant Staphylococcus aureus prosthetic joint infection is associated with resistance to host defense cationic peptides and mprF polymorphisms.

BackgroundPrevious studies of both clinically-derived and in vitro passage-derived daptomycin-resistant (DAP-R) Staphylococcus aureus strains demonstrated the coincident emergence of increased DAP MICs and resistance to host defense cationic peptides (HDP-R).MethodsIn the present investigation, we studied a parental DAP-susceptible (DAP-S) methicillin-resistant Staphylococcus aureus (MRSA) strain and three isogenic variants with increased DAP MICs which were isolated from both DAP-treated and DAP-untreated rabbits with prosthetic joint infections. These strains were compared for: in vitro susceptibility to distinct HDPs differing in size, structure, and origin; i.e.; thrombin-induced platelet microbicidal proteins [tPMPs] and human neutrophil peptide-1 [hNP-1]; cell membrane (CM) phospholipid and fatty acid content; CM order; envelope surface charge; cell wall thickness; and mprF single nucleotide polymorphisms (SNPs) and expression profiles.ResultsIn comparison with the parental strain, both DAP-exposed and DAP-naive strains exhibited: (i) significantly reduced susceptibility to each HDP (P<0.05); (ii) thicker cell walls (P<0.05); (iii) increased synthesis of CM lysyl-phosphatidylglycerol (L-PG); (iv) reduced content of CM phosphatidylglycerol (PG); and (v) SNPs within the mprF locus No significant differences were observed between parental or variant strains in outer CM content of L-PG, CM fluidity, CM fatty acid contents, surface charge, mprF expression profiles or MprF protein content. An isolate which underwent identical in vivo passage, but without evolving increased DAP MICs, retained parental phenotypes and genotype.ConclusionsTHESE RESULTS SUGGEST: i) DAP MIC increases may occur in the absence of DAP exposures in vivo and may be triggered by organism exposure to endogenous HDPs: and ii) gain-in-function SNPs in mprF may contribute to such HDP-DAP cross-resistance phenotypes, although the mechanism of this relationship remains to be defined

Knowledge and training in paediatric medical traumatic stress and trauma-informed care among emergency medical professionals in low- and middle-income countries

© 2018, © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Background: Provision of psychosocial care, in particular trauma-informed care, in the immediate aftermath of paediatric injury is a recommended strategy to minimize the risk of paediatric medical traumatic stress. Objective: To examine the knowledge of paediatric medical traumatic stress and perspectives on providing trauma-informed care among emergency staff working in low- and middle-income countries (LMICs). Method: Training status, knowledge of paediatric medical traumatic stress, attitudes towards incorporating psychosocial care and barriers experienced were assessed using an online self-report questionnaire. Respondents included 320 emergency staff from 58 LMICs. Data analyses included descriptive statistics, t-tests and multiple regression. Results: Participating emergency staff working in LMICs had a low level of knowledge of paediatric medical traumatic stress. Ninety-one percent of respondents had not received any training or education in paediatric medical traumatic stress, or trauma-informed care for injured children, while 94% of respondents indicated they wanted training in this area. Conclusions: There appears to be a need for training and education of emergency staff in LMICs regarding paediatric medical traumatic stress and trauma-informed care, in particular among staff working in comparatively lower income countries

The queen part in the tolerance between worker bees, Apis mellifera mellifera

The intolerance and the aggressive behaviour of worker bees towards alien individuals of the hive are widely known. But, in particular circumstances, worker bees of different hives can live together without fighting. Thus, it seemed interesting to look for factors which can stop the aggressive behaviour of the honeybee towards alien individuals. Basic to our understanding of these behaviours is the effect of the colony odour. However, colony odour may have various origins, including the hive materials and metabolic products of the workers or the queen. We orientated our research towards investigating the effects of the queen's metabolism. Experiments were made with populations of 75 workers of various ages taken from the same hive and kept in cages. Seventy-two h elapsed between the time when the workers were put in cages and the first observation. Five workers were introduced from cage X into cage Y, and vice versa, and the aggressiveness of the receiver workers towards one worker chosen amongst the five workers introduced was classified from 1 (no aggressiveness) to 5 (struggle and killing of the intruder). Every set of observations lasted 10 min and was repeated daily for 7 days. We demonstrated that the queen's odour played an important part in the colony odour. We now know that : 1) queenless sister workers readily recognize one another, even a long time after their separation (table I); 2) workers living with a queen easily accept their queenless sisters (table II: lines "X en Y"); 3) queenless workers reject their sisters that have lived with a queen for 72 h (table II: lines "Y en X"). The two first results may be explained by aspects of kin recognition but not the last one. We hypothesize that queenless workers slowly lose their queen's odour, while workers with queens are continuously marked by the queen pheromone