University student-led public engagement event: increasing audience diversity and impact in a non-science space.

There is a wealth of innovation in microbiology outreach events globally, including in the setting where the public engagement is hosted. Previous data indicate an underrepresentation of marginalized ethnic groups attending UK science-based public engagement events. This project engaged our student cohort, encompassing a diverse range of ethnic groups, to create an integrated art and science event within an existing series of adult education evenings. The study's objectives were to increase the proportion of visitors from marginalized ethnic groups and to gain a greater understanding of the impact of the event on the visitors' reported science capital. The participants' demographics, links to our students and University, and detailed impact on participants' science capital of the event were determined through analysis of exit questionnaires. There was an increase in the proportion of marginalized ethnic group visitors compared to similar previous events. A higher proportion of visitors from marginalized ethnic groups had links with our students and University compared to white/white British visitors. Elements of the exit questionnaire were mapped to the science capital framework and participants' science capital was determined. Both ethnically marginalized participants and white/white British visitors showed an increase in science capital, specifically dimensions of science-related social capital and science-related cultural capital, after the event. In conclusion, our study suggests that a student-led blended art and science public engagement can increase the ethnic diversity of those attending and can contribute towards creating more inclusive public engagement events.

What Is Targeted When We Train Working Memory? Evidence From a Meta-Analysis of the Neural Correlates of Working Memory Training Using Activation Likelihood Estimation.

Working memory (WM) is the system responsible for maintaining and manipulating information, in the face of ongoing distraction. In turn, WM span is perceived to be an individual-differences construct reflecting the limited capacity of this system. Recently, however, there has been some evidence to suggest that WM capacity can increase through training, raising the possibility that training can functionally alter the neural structures supporting WM. To address the hypothesis that the neural substrates underlying WM are targeted by training, we conducted a meta-analysis of functional magnetic resonance imaging (fMRI) studies of WM training using Activation Likelihood Estimation (ALE). Our results demonstrate that WM training is associated exclusively with decreases in blood oxygenation level-dependent (BOLD) responses in clusters within the fronto-parietal system that underlie WM, including the bilateral inferior parietal lobule (BA 39/40), middle (BA 9) and superior (BA 6) frontal gyri, and medial frontal gyrus bordering on the cingulate gyrus (BA 8/32). We discuss the various psychological and physiological mechanisms that could be responsible for the observed reductions in the BOLD signal in relation to WM training, and consider their implications for the construct of WM span as a limited resource.

Nights at the museum: integrated arts and microbiology public engagement events enhance understanding of science whilst increasing community diversity and inclusion.

This study uses integrated art and science events to explore a blended approach in improving public understanding of current scientific topics and widening participation within the local community. The events were a Halloween-inspired microbiology-themed series of interactive exhibitions hosted within a national museum as part of an existing series of adult education evenings. A representative sample of 102 mixed methods exit questionnaires, based on determining (i) audience diversity and (ii) understanding of scientific topics, were analysed by qualitative and quantitative approaches, and a post-attendance focus group was carried out to determine longer term impact of the event. Participants were grouped as 'Science', 'Arts', 'Both' or 'Neither', according to their past experience and engagement. These events welcomed more participants from the Arts and Neither subsections hence engaging a group of people who would not usually visit science public engagement events or comparative events hosted in traditional academic settings, highlighting the importance of venue choice in reaching new audiences and widening participation. An increase in perceived understanding of science was observed by all groups of participants with reported enjoyment focused around the science talks, presentations and blended art-science activities. A putative impact in science capital is observed with participants reporting an increased likelihood of attending science events in the future. Furthermore, increased discussion and awareness of science in society is evidenced by participants. Blended art and microbiology exhibitions enhance the accessibly of science public engagement events and is likely to increase science capital; the impact of this on cognitive polyphasia is also discussed.

Perpetration of Alcohol-Related Aggression by Male and Female College Students: An Examination of Overt and Relational Aggression.

Existing literature exemplifies the relationship between alcohol and overt aggression, especially for adult males. Less clear is the relationship between alcohol and aggression among male and female college students, in particular, the nature of this aggression and the co-occurrence of drinking and aggression on the same day (temporal proximity). This study examines the chronic and temporal nature of males' and females' alcohol-related aggression among college students. Two hundred fourteen students completed a web-based 7-day event-level survey measuring alcohol consumption and perpetration of physical aggression, verbal aggression, anger, and relational aggression over 4 weeks, resulting in 4,256 observations (days). The global analysis revealed students who are heavy drinkers are more likely to perpetrate all four forms of aggression, whereas the event-level analysis revealed that specific forms of aggression are associated with drinking at the time, while other forms were not linked to drinking occasions. Cross-tabulation revealed males and females were more likely to use verbal and physical aggression when drinking. For females, drinking was also associated with relational aggression and anger. Despite often being overlooked in research on aggression during emerging adulthood, relational aggression was prevalent. Discrepancies between the global and temporal analysis revealed factors other than alcohol might explain the relationship between chronic alcohol consumption and specific forms of aggression. This is one of the first event-level studies to show the temporal relationship between alcohol and relational aggression. The distinctions in the current study, exemplifying the diversity of alcohol-related aggression, are critical for understanding aggressive behavior, potential gender differences, and for developing interventions. The temporal relationship between alcohol and aggression suggests health interventions should target drinking and aggression simultaneously.

Non-attendance at urgent referral appointments for suspected cancer: a qualitative study to gain understanding from patients and GPs.

BACKGROUND: The 2-week-wait urgent referral policy in the UK has sought to improve cancer outcomes by accelerating diagnosis and treatment. However, around 5-7% of symptomatic referred patients cancel or do not attend their hospital appointment. While subsequent cancer diagnosis was less likely in non-attenders, those with a diagnosis had worse early mortality outcomes. AIM: To examine how interpersonal, communication, social, and organisational factors influence a patient's non-attendance. DESIGN AND SETTING: Qualitative study in GP practices in one Northern English city. METHOD: In-depth, individual interviews were undertaken face-to-face or by telephone between December 2016 and May 2018, followed by thematic framework analysis. RESULTS: In this study 21 GPs, and 24 patients who did not attend or had cancelled their appointment were interviewed, deriving a range of potential explanations for non-attendance, including: system flaws; GP difficulties with booking appointments; patient difficulties with navigating the appointment system, particularly older patients and those from more deprived areas; patients leading 'difficult lives'; and patients' expectations of the referral, informed by their beliefs, circumstances, priorities, and the perceived prognosis. GPs recognised the importance of communication with the patient, particularly the need to tailor communication to perceived patient understanding and anxiety. GPs and practices varied in their responses to patient non-attendance, influenced by time pressures and perceptions of patient responsibility. CONCLUSION: Failure to be seen within 2 weeks of urgent referral resulted from a number of patient and provider factors. The urgent referral process in general practice and cancer services should accommodate patient perceptions and responses, facilitate referral and attendance, and enable responses to patient non-attendance.

Non-attendance at urgent referral appointments for suspected cancer: a qualitative study to gain understanding from patients and GPs.

BACKGROUND: The 2-week-wait urgent referral policy in the UK has sought to improve cancer outcomes by accelerating diagnosis and treatment. However, around 5-7% of symptomatic referred patients cancel or do not attend their hospital appointment. While subsequent cancer diagnosis was less likely in non-attenders, those with a diagnosis had worse early mortality outcomes. AIM: To examine how interpersonal, communication, social, and organisational factors influence a patient's non-attendance. DESIGN AND SETTING: Qualitative study in GP practices in one Northern English city. METHOD: In-depth, individual interviews were undertaken face-to-face or by telephone between December 2016 and May 2018, followed by thematic framework analysis. RESULTS: In this study 21 GPs, and 24 patients who did not attend or had cancelled their appointment were interviewed, deriving a range of potential explanations for non-attendance, including: system flaws; GP difficulties with booking appointments; patient difficulties with navigating the appointment system, particularly older patients and those from more deprived areas; patients leading 'difficult lives'; and patients' expectations of the referral, informed by their beliefs, circumstances, priorities, and the perceived prognosis. GPs recognised the importance of communication with the patient, particularly the need to tailor communication to perceived patient understanding and anxiety. GPs and practices varied in their responses to patient non-attendance, influenced by time pressures and perceptions of patient responsibility. CONCLUSION: Failure to be seen within 2 weeks of urgent referral resulted from a number of patient and provider factors. The urgent referral process in general practice and cancer services should accommodate patient perceptions and responses, facilitate referral and attendance, and enable responses to patient non-attendance.

Patient non-attendance at urgent referral appointments for suspected cancer and its links to cancer diagnosis and one year mortality: A cohort study of patients referred on the Two Week Wait pathway.

BACKGROUND: The 'Two Week Wait' policy aims to ensure patients with suspected cancer are seen within two weeks of referral. However, patient non-attendance can result in this target being missed. This study aimed to identify predictors of non-attendance; and analyse the relationship between attendance and outcomes including cancer diagnosis and early mortality. METHODS: A cohort study of 109,433 adults registered at 105 general practices, referred to a cancer centre within a large NHS hospital trust (April 2009 to December 2016) on the 'Two Week Wait' pathway. RESULTS: 5673 (5.2%) patients did not attend. Non-attendance was largely predicted by patient factors (younger and older age, male gender, greater deprivation, suspected cancer site, earlier year of referral, greater distance to the hospital) over practice factors (greater deprivation, lower Quality and Outcomes Framework score, lower cancer conversion rate, lower cancer detection rate). 10,360 (9.6%) patients were diagnosed with cancer within six months of referral (9.8% attending patients, 5.6% non-attending patients). Among these patients, 2029 (19.6%) died within 12 months of diagnosis: early mortality risk was 31.3% in non-attenders and 19.2% in attending patients. CONCLUSIONS: Non-attendance at urgent referral appointments for suspected cancer involves a minority of patients but happens in predictable groups. Cancer diagnosis was less likely in non-attending patients but these patients had worse early mortality outcomes than attending patients. The study findings have implications for cancer services and policy.

Visualization and Quantification of the Oral Hygiene Effects of Brushing, Dentifrice Use, and Brush Wear Using a Tooth Brushing Simulator.

Approaches that reproduce dental hygiene regimens under controlled conditions have applications in preclinical research. We have applied standardized, reproducible brushing regimes to typodonts coated in simulated or biological plaques to assess the effects on tooth cleaning of toothbrush/dentifrice regimens. Replicated typodonts were coated with OccludeTM or GlogermTM indicators to simulate plaque, and brushed reproducibly using a mechanical brushing simulator to compare the cleaning of occlusal surfaces before and after brushing with water or a dentifrice. An in vitro model using salivary inocula to cultivate oral biofilms on typodont surfaces was then developed to evaluate removal of disclosed plaque by new toothbrushes in comparison to toothbrushes with wear equivalent to 3 months of use. Analyses of typodonts brushed under controlled conditions significantly (p < 0.01) distinguished between brushed and unbrushed surfaces and between the use of water vs. dentifrice for the removal of simulated interproximal plaque (p < 0.05). New toothbrushes removed significantly (p < 0.05) more biological plaque from typodont surfaces than brushes that had been worn by repeated brushing. Through controlled and defined brushing of typodonts with simulated and biological plaques, the effectiveness of dental hygiene regimens was compared under reproducible conditions. Data indicate that the cleaning effectiveness of brushing was augmented by the addition of dentifrice and that new brushes were significantly more effective than brushes with substantial wear from previous use. Whilst we have focussed on the occlusal surfaces of molars and worn brushes, the method could be applied to a range of other tooth surfaces and oral hygiene regimens.

Loss of Function in Escherichia coli Exposed to Environmentally Relevant Concentrations of Benzalkonium Chloride.

Assessing the risk of resistance associated with biocide exposure commonly involves exposing microorganisms to biocides at concentrations close to the MIC. With the aim of representing exposure to environmental biocide residues, Escherichia coli MG1655 was grown for 20 passages in the presence or absence of benzalkonium chloride (BAC) at 100 ng/liter and 1,000 ng/liter (0.0002% and 0.002% of the MIC, respectively). BAC susceptibility, planktonic growth rates, motility, and biofilm formation were assessed, and differentially expressed genes were determined via transcriptome sequencing. Planktonic growth rate and biofilm formation were significantly reduced (P < 0.001) following BAC adaptation, while BAC minimum bactericidal concentration increased 2-fold. Transcriptomic analysis identified 289 upregulated and 391 downregulated genes after long-term BAC adaptation compared with the respective control organism passaged in BAC-free medium. When the BAC-adapted bacterium was grown in BAC-free medium, 1,052 genes were upregulated and 753 were downregulated. Repeated passage solely in biocide-free medium resulted in 460 upregulated and 476 downregulated genes compared with unexposed bacteria. Long-term exposure to environmentally relevant BAC concentrations increased the expression of genes associated with efflux and reduced the expression of genes associated with outer-membrane porins, motility, and chemotaxis. This was manifested phenotypically through the loss of function (motility). Repeated passage in a BAC-free environment resulted in the upregulation of multiple respiration-associated genes, which was reflected by increased growth rate. In summary, repeated exposure of E. coli to BAC residues resulted in significant alterations in global gene expression that were associated with minor decreases in biocide susceptibility, reductions in growth rate and biofilm formation, and loss of motility.IMPORTANCE Exposure to very low concentrations of biocides in the environment is a poorly understood risk factor for antimicrobial resistance. Repeated exposure to trace levels of the biocide benzalkonium chloride (BAC) resulted in loss of function (motility) and a general reduction in bacterial fitness but relatively minor decreases in susceptibility. These changes were accompanied by widespread changes in the Escherichia coli transcriptome. These results demonstrate the importance of including phenotypic characterization in studies designed to assess the risks of biocide exposure.

Signaling of free fatty acid receptors 2 and 3 differs in colonic mucosa following selective agonism or coagonism by luminal propionate.

BACKGROUND: Propionate exhibits affinity for free fatty acid receptor 2 (FFA2, formerly GPR43) and FFA3 (GPR41). These two G protein-coupled receptors (GPCRs) are expressed by enteroendocrine L cells that contain anorectic peptide YY (PYY) and glucagon-like peptide 1 (GLP-1), while FFA3 is also expressed by enteric neurons. Few studies have investigated the individual roles of FFA2 and FFA3 in propionate's gastrointestinal (GI) effects. Here, we compared FFA2, FFA3, and propionate mucosal responses utilizing selective ligands including an FFA3 antagonist, in mouse and human colonic mucosa. METHODS: Vectorial ion transport was measured in native colonic preparations from normal mouse and human colon with intact submucosal innervation. Endogenous fecal pellet propulsion was monitored in colons isolated from wild-type (WT) and PYY-/- mice. KEY RESULTS: FFA2 and FFA3 signaling differed significantly. FFA2 agonism involved endogenous L cell-derived PYY and was glucose dependent, while FFA3 agonism was independent of PYY and glucose, but required submucosal enteric neurons for activity. Tonic FFA3 activity was observed in mouse and human colon mucosa. Apical propionate responses were a combination of FFA2-PYY mediation and FFA3 neuronal GLP-1- and CGRP-dependent signaling in mouse ascending colon mucosa. Propionate also slowed WT and PYY-/- colonic transit, and this effect was blocked by a GLP-1 receptor antagonist. CONCLUSIONS & INFERENCES: We conclude that luminal propionate costimulates FFA2 and FFA3 pathways, reducing anion secretion and slowing colonic motility; FFA2 via PYY mediation and FFA3 signaling by activation of enteric sensory neurons.

The Reflective Mind: Examining Individual Differences in Susceptibility to Base Rate Neglect with fMRI.

Performance on heuristics and bias tasks has been shown to be susceptible to bias. In turn, susceptibility to bias varies as a function of individual differences in cognitive abilities (e.g., intelligence) and thinking styles (e.g., propensity for reflection). Using a classic task (i.e., lawyer-engineer problem), we conducted two experiments to examine the differential contributions of cognitive abilities versus thinking styles to performance. The results of Experiment 1 demonstrated that the Cognitive Reflection Test (CRT)-a well-established measure of reflective thinking-predicted performance on conflict problems (where base rates and intuition point in opposite directions), whereas STM predicted performance on nonconflict problems. Experiment 2 conducted in the fMRI scanner replicated this behavioral dissociation and enabled us to probe their neural correlates. As predicted, conflict problems were associated with greater activation in the ACC-a key region for conflict detection-even in cases when participants responded stereotypically. In participants with higher CRT scores, conflict problems were associated with greater activation in the posterior cingulate cortex (PCC), and activation in PCC covaried in relation to CRT scores during conflict problems. Also, CRT scores predicted activation in PCC in conflict problems (over and above nonconflict problems). Our results suggest that individual differences in reflective thinking as measured by CRT are related to brain activation in PCC-a region involved in regulating attention between external and internal foci. We discuss the implications of our findings in terms of PCC's possible involvement in switching from intuitive to analytic mode of thought.

Fatty Acid Supplementation Reverses the Small Colony Variant Phenotype in Triclosan-Adapted Staphylococcus aureus: Genetic, Proteomic and Phenotypic Analyses.

Staphylococcus aureus can develop a small colony variant (SCV) phenotype in response to sub-lethal exposure to the biocide triclosan. In the current study, whole genome sequencing was performed and changes in virulence were investigated in five Staphylococcus aureus strains following repeated exposure to triclosan. Following exposure, 4/5 formed SCV and exhibited point mutations in the triclosan target gene fabI with 2/4 SCVs showing mutations in both fabI and fabD. The SCV phenotype was in all cases immediately reversed by nutritional supplementation with fatty acids or by repeated growth in the absence of triclosan, although fabI mutations persisted in 3/4 reverted SCVs. Virulence, determined using keratinocyte invasion and Galleria mellonella pathogenicity assays was significantly (p < 0.05) attenuated in 3/4 SCVs and in the non-SCV triclosan-adapted bacterium. Proteomic analysis revealed elevated FabI in 2/3 SCV and down-regulation in a protein associated with virulence in 1/3 SCV. In summary, attenuated keratinocyte invasion and larval virulence in triclosan-induced SCVs was associated with decreases in growth rate and virulence factor expression. Mutation occurred in fabI, which encodes the main triclosan target in all SCVs and the phenotype was reversed by fatty acid supplementation, demonstrating an association between fatty acid metabolism and triclosan-induced SCV.

Bidirectional GPR119 Agonism Requires Peptide YY and Glucose for Activity in Mouse and Human Colon Mucosa.

The lipid sensor G protein-coupled receptor 119 (GPR119) is highly expressed by enteroendocrine L-cells and pancreatic ß-cells that release the hormones, peptide YY (PYY) and glucagonlike peptide 1, and insulin, respectively. Endogenous oleoylethanolamide (OEA) and the dietary metabolite, 2-monoacylglycerol (2-OG), can each activate GPR119. Here, we compared mucosal responses with selective, synthetic GPR119 agonists (AR440006 and AR231453) and the lipids, OEA, 2-OG, and N-oleoyldopamine (OLDA), monitoring epithelial ion transport as a readout for L-cell activity in native mouse and human gastrointestinal (GI) mucosae. We also assessed GPR119 modulation of colonic motility in wild-type (WT), GPR119-deficient (GPR119-/-), and PYY-deficient (PYY-/-) mice. The water-soluble GPR119 agonist, AR440006 (that cannot traverse epithelial tight junctions), elicited responses, when added apically or basolaterally in mouse and human colonic mucosae. In both species, GPR119 responses were PYY, Y1 receptor mediated, and glucose dependent. AR440006 efficacy matched the GI distribution of L-cells in WT tissues but was absent from GPR119-/- tissue. OEA and 2-OG responses were significantly reduced in the GPR119-/- colon, but OLDA responses were unchanged. Alternative L-cell activation via free fatty acid receptors 1, 3, and 4 and the G protein-coupled bile acid receptor TGR5 or by the melanocortin 4 receptor, was unchanged in GPR119-/- tissues. The GPR119 agonist slowed transit in WT but not the PYY-/- colon in vitro. AR440006 (intraperitoneally) slowed WT colonic and upper-GI transit significantly in vivo. These data indicate that luminal or blood-borne GPR119 agonism can stimulate L-cell PYY release with paracrine consequences and slower motility. We suggest that this glucose-dependent L-cell response to a gut-restricted GPR119 stimulus has potential therapeutic advantage in modulating insulinotropic signaling with reduced risk of hypoglycemia.

One-way traffic: The inferior frontal gyrus controls brain activation in the middle temporal gyrus and inferior parietal lobule during divergent thinking.

Contrary to earlier approaches that focused on the contributions of isolated brain regions to the emergence of creativity, there is now growing consensus that creative thought emerges from the interaction of multiple brain regions, often embedded within larger brain networks. Specifically, recent evidence from studies of divergent thinking suggests that kernel ideas emerge in posterior brain regions residing within the semantic system and/or the default mode network (DMN), and that the prefrontal cortex (PFC) regions within the executive control network (ECN) constrain those ideas for generating outputs that meet task demands. However, despite knowing that regions within these networks exhibit interaction, to date the direction of the relationship has not been tested directly. By applying Dynamic Causal Modeling (DCM) to fMRI data collected during a divergent thinking task, we tested the hypothesis that the PFC exerts unidirectional control over the middle temporal gyrus (MTG) and the inferior parietal lobule (IPL), vs. the hypothesis that these two sets of regions exert bidirectional control over each other (in the form of feedback loops). The data were consistent with the former model by demonstrating that the right inferior frontal gyrus (IFG) exerts unidirectional control over MTG and IPL, although the evidence was somewhat stronger in the case of the MTG than the IPL. Our findings highlight potential causal pathways that could underlie the neural bases of divergent thinking.

Formulation of Biocides Increases Antimicrobial Potency and Mitigates the Enrichment of Nonsusceptible Bacteria in Multispecies Biofilms.

The current investigation aimed to generate data to inform the development of risk assessments of biocide usage. Stabilized domestic drain biofilm microcosms were exposed daily over 6 months to increasing concentrations (0.01% to 1%) of the biocide benzalkonium chloride (BAC) in a simple aqueous solution (BAC-s) or in a complex formulation (BAC-f) representative of a domestic cleaning agent. Biofilms were analyzed by culture, differentiating by bacterial functional group and by BAC or antibiotic susceptibility. Bacterial isolates were identified by 16S rRNA sequencing, and changes in biofilm composition were assessed by high-throughput sequencing. Exposure to BAC-f resulted in significantly larger reductions in levels of viable bacteria than exposure to BAC-s, while bacterial diversity greatly decreased during exposure to both BAC-s and BAC-f, as evidenced by sequencing and viable counts. Increases in the abundance of bacteria exhibiting reduced antibiotic or BAC susceptibility following exposure to BAC at 0.1% were significantly greater for BAC-s than BAC-f. Bacteria with reduced BAC and antibiotic susceptibility were generally suppressed by higher BAC concentrations, and formulation significantly enhanced this effect. Significant decreases in the antimicrobial susceptibility of bacteria isolated from the systems before and after long-term BAC exposure were not detected. In summary, dose-dependent suppression of bacterial viability by BAC was enhanced by formulation. Biocide exposure decreased bacterial diversity and transiently enriched populations of organisms with lower antimicrobial susceptibility, and the effects were subsequently suppressed by exposure to 1% BAC-f, the concentration most closely reflecting deployment in formulated products.IMPORTANCE Assessment of the risks of biocide use has been based mainly on the exposure of axenic cultures of bacteria to biocides in simple aqueous solutions. The current investigation aimed to assess the effects of formulation on the outcome of biocide exposure in multispecies biofilms. Formulation of the cationic biocide BAC significantly increased antimicrobial potency. Bacteria with lower antimicrobial susceptibility whose populations were enriched after low-level biocide exposure were more effectively suppressed by the biocide at in-use concentrations (1% [wt/vol]) in a formulation than in a simple aqueous solution. These observations underline the importance of simulating normal deployment conditions in considering the risks and benefits of biocide use.

Variable Effects of Exposure to Formulated Microbicides on Antibiotic Susceptibility in Firmicutes and Proteobacteria.

UNLABELLED: Microbicides are broad-spectrum antimicrobial agents that generally interact with multiple pharmacological targets. While they are widely deployed in disinfectant, antiseptic, and preservative formulations, data relating to their potential to select for microbicide or antibiotic resistance have been generated mainly by testing the compounds in much simpler aqueous solutions. In the current investigation, antibiotic susceptibility was determined for bacteria that had previously exhibited decreased microbicide susceptibility following repeated exposure to microbicides either in formulation with sequestrants and surfactants or in simple aqueous solution. Statistically significant increases in antibiotic susceptibility occurred for 12% of bacteria after exposure to microbicides in formulation and 20% of bacteria after exposure to microbicides in aqueous solutions, while 22% became significantly less susceptible to the antibiotics, regardless of formulation. Of the combinations of a bacterium and an antibiotic for which British Society for Antimicrobial Chemotherapy breakpoints are available, none became resistant. Linear modeling taking into account phylogeny, microbicide, antibiotic, and formulation identified small but significant effects of formulation that varied depending on the bacterium and microbicide. Adaptation to formulated benzalkonium chloride in particular was more likely to increase antibiotic susceptibility than adaptation to the simple aqueous solution. In conclusion, bacterial adaptation through repeated microbicide exposure was associated with both increases and decreases in antibiotic susceptibility. Formulation of the microbicide to which the bacteria had previously adapted had an identifiable effect on antibiotic susceptibility, but it effect was typically small relative to the differences observed among microbicides. Susceptibility changes resulting in resistance were not observed. IMPORTANCE: The safety of certain microbicide applications has been questioned due to the possibility that microbicide exposure could select for microbicide and antibiotic resistance. Evidence that this may happen is based mainly on in vitro experiments where bacteria have been exposed to microbicides in aqueous solution. Microbicides are, however, normally deployed in products formulated with surfactants, sequestrants, and other compounds. While this may influence the frequency and extent of susceptibility changes, few studies reported in the literature have assessed this. In the current investigation, therefore, we have investigated changes in antibiotic susceptibility in bacteria which exhibited decreased microbicide susceptibility following repeated exposure to microbicides in simple aqueous solutions and in formulation. We report that the microbicide formulation had an identifiable effect on antibiotic susceptibility, but it was typically small relative to the differences observed among microbicides. We did not observe susceptibility changes resulting in resistance.

Simultaneous Assessment of Acidogenesis-Mitigation and Specific Bacterial Growth-Inhibition by Dentifrices.

Dentifrices can augment oral hygiene by inactivating bacteria and at sub-lethal concentrations may affect bacterial metabolism, potentially inhibiting acidogenesis, the main cause of caries. Reported herein is the development of a rapid method to simultaneously measure group-specific bactericidal and acidogenesis-mitigation effects of dentifrices on oral bacteria. Saliva was incubated aerobically and anaerobically in Tryptone Soya Broth, Wilkins-Chalgren Broth with mucin, or artificial saliva and was exposed to dentifrices containing triclosan/copolymer (TD); sodium fluoride (FD); stannous fluoride and zinc lactate (SFD1); or stannous fluoride, zinc lactate and stannous chloride (SFD2). Minimum inhibitory concentrations (MIC) were determined turbidometrically whilst group-specific minimum bactericidal concentrations (MBC) were assessed using growth media and conditions selective for total aerobes, total anaerobes, streptococci and Gram-negative anaerobes. Minimum acid neutralization concentration (MNC) was defined as the lowest concentration of dentifrice at which acidification was inhibited. Differences between MIC and MNC were calculated and normalized with respect to MIC to derive the combined inhibitory and neutralizing capacity (CINC), a cumulative measure of acidogenesis-mitigation and growth inhibition. The overall rank order for growth inhibition potency (MIC) under aerobic and anaerobic conditions was: TD> SFD2> SFD1> FD. Acidogenesis-mitigation (MNC) was ordered; TD> FD> SFD2> SFD1. CINC was ordered TD> FD> SFD2> SFD1 aerobically and TD> FD> SFD1> SFD2 anaerobically. With respect to group-specific bactericidal activity, TD generally exhibited the greatest potency, particularly against total aerobes, total anaerobes and streptococci. This approach enables the rapid simultaneous evaluation of acidity mitigation, growth inhibition and specific antimicrobial activity by dentifrices.

Selective FFA2 Agonism Appears to Act via Intestinal PYY to Reduce Transit and Food Intake but Does Not Improve Glucose Tolerance in Mouse Models.

Free fatty acid receptor 2 (FFA2) is expressed on enteroendocrine L cells that release glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) when activated by short-chain fatty acids (SCFAs). Functionally GLP-1 and PYY inhibit gut transit, increase glucose tolerance, and suppress appetite; thus, FFA2 has therapeutic potential for type 2 diabetes and obesity. However, FFA2-selective agonists have not been characterized in vivo. Compound 1 (Cpd 1), a potent FFA2 agonist, was tested for its activity on the following: GLP-1 release, modulation of intestinal mucosal ion transport and transit in wild-type (WT) and FFA2(-/-) tissue, and food intake and glucose tolerance in lean and diet-induced obese (DIO) mice. Cpd 1 stimulated GLP-1 secretion in vivo, but this effect was only detected with dipeptidyl peptidase IV inhibition, while mucosal responses were PYY, not GLP-1, mediated. Gut transit was faster in FFA2(-/-) mice, while Cpd 1 slowed WT transit and reduced food intake and body weight in DIO mice. Cpd 1 decreased glucose tolerance and suppressed plasma insulin in lean and DIO mice, despite FFA2(-/-) mice displaying impaired glucose tolerance. These results suggest that FFA2 inhibits intestinal functions and suppresses food intake via PYY pathways, with limited GLP-1 contribution. Thus, FFA2 may be an effective therapeutic target for obesity but not for type 2 diabetes.

Effects of Formulation on Microbicide Potency and Mitigation of the Development of Bacterial Insusceptibility.

Risk assessments of the potential for microbicides to select for reduced bacterial susceptibility have been based largely on data generated through the exposure of bacteria to microbicides in aqueous solution. Since microbicides are normally formulated with multiple excipients, we have investigated the effect of formulation on antimicrobial activity and the induction of bacterial insusceptibility. We tested 8 species of bacteria (7 genera) before and after repeated exposure (14 passages), using a previously validated gradient plating system, for their susceptibilities to the microbicides benzalkonium chloride, benzisothiozolinone, chlorhexidine, didecyldimethyl ammonium chloride, DMDM-hydantoin, polyhexamethylene biguanide, thymol, and triclosan in aqueous solution (nonformulated) and in formulation with excipients often deployed in consumer products. Susceptibilities were also assessed following an additional 14 passages without microbicide to determine the stability of any susceptibility changes. MICs and minimum bactericidal concentrations (MBC) were on average 11-fold lower for formulated microbicides than for nonformulated microbicides. After exposure to the antimicrobial compounds, of 72 combinations of microbicide and bacterium there were 19≥4-fold (mean, 8-fold) increases in MIC for nonformulated and 8≥4-fold (mean, 2-fold) increases in MIC for formulated microbicides. Furthermore, there were 20≥4-fold increases in MBC (mean, 8-fold) for nonformulated and 10≥4-fold (mean, 2-fold) increases in MBC for formulated microbicides. Susceptibility decreases fully or partially reverted back to preexposure values for 49% of MICs and 72% of MBCs after further passage. In summary, formulated microbicides exhibited greater antibacterial potency than unformulated actives and susceptibility decreases after repeated exposure were lower in frequency and extent.