Upon infection of their host, temperate phages (viruses that infect bacteria) enter either a lytic or a lysogenic cycle. The former results in bacterial cell lysis and phage release (horizontal transmission), while lysogeny is characterized by integration of the phage in the host genome and dormancy (vertical transmission) 1. Co-culture experiments of bacteria and temperate phage mutants, which are locked in the lytic cycle, have shown that CRISPR-Cas can efficiently Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:

CRISPR-Cas systems are widespread in bacterial and archaeal genomes, and in their canonical role in phage defence they confer a fitness advantage. However, CRISPR-Cas may also hinder the uptake of potentially beneficial genes. This is particularly true under antibiotic selection, where preventing the uptake of antibiotic resistance genes could be detrimental. Newly discovered features within these evolutionary dynamics are anti-CRISPR genes, which inhibit specific CRISPR-Cas systems. We hypothesized that selection for antibiotic resistance might have resulted in an accumulation of anti-CRISPR genes in genomes that harbour CRISPR-Cas systems and horizontally acquired antibiotic resistance genes. To assess that question, we analysed correlations between the CRISPR-Cas, anti-CRISPR and antibiotic resistance gene content of 104 947 reference genomes, including 5677 different species. In most species, the presence of CRISPR-Cas systems did not correlate with the presence of antibiotic resistance genes. However, in some clinically important species, we observed either a positive or negative correlation of CRISPR-Cas with antibiotic resistance genes. Anti-CRISPR genes were common enough in four species to be analysed. In Pseudomonas aeruginosa , the presence of anti-CRISPRs was associated with antibiotic resistance genes. This analysis indicates that the role of CRISPR-Cas and anti-CRISPRs in the spread of antibiotic resistance is likely to be very different in particular pathogenic species and clinical environments. This article is part of a discussion meeting issue ‘The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems’.

IntroductionStudies have reported associations between serum anticholinergic activity (SAA) and decline in cognitive performance, delirium, and functional impairment. The aim of this meta-analysis was to explore and quantify associations between SAA and adverse cognitive and functional outcomes in older people.Materials and MethodsA literature search in Ovid MEDLINE, EMBASE, PsycINFO and IPA from 1946–2014 was completed. The primary outcomes of interest were cognitive and functional adverse outcomes associated with SAA in older people aged 55 years and above. The Cochrane Risk-Bias assessment tool was used to assess bias in randomised controlled trials (RCTs). The Newcastle-Ottawa Scale was used to assess the quality of non-RCTs. Meta-analyses were conducted for RCTs and cohort studies separately. Heterogeneity was assessed using I2 tests.ResultsThe primary electronic literature search identified a total of 1559 records in the 4 different databases. On the basis of full-text analysis, 33 studies that met the inclusion criteria. The review included 4 RCTs, 5 prospective cohort studies, 3 longitudinal cohort studies, 17 cross-sectional studies, and 4 case-control studies. Twenty-four of the retrieved studies examined an association between SAA and cognitive outcomes, 2 studies examined an association with SAA and functional outcomes and 8 studies examined associations between SAA and both cognitive, and functional outcomes. The meta-analysis on 4 RCTs showed no association with higher SAA and cognitive performance (I2 = 89.38%, H2 = 25.53 and p-value = <0.05) however, the pooled data from 4 observational studies showed elevated SAA was associated with reduced cognitive performance (I2 = 0.00%, H2 = 3.37 and p-value = 0.34).ConclusionThis systematic review summarises the limitations of the SAA on predicting cognitive and functional outcomes in older people. SAA measured by receptor bioassay is flawed and its use in older people with multimorbidity and polypharmacy is questionable.

Mepitel Film reduced acute radiation-induced skin reactions in our head and neck cancer patients, particularly in patients without heavy stubble. Advances in knowledge: This is the first study to confirm the feasibility of using Mepitel Film in head and neck cancer patients.