TRAP220 is modulated by the antineoplastic agent 6-Mercaptopurine, and mediates the activation of the NR4A subgroup of nuclear receptors

The NR4A1-3 (Nur77, NURR1 and NOR-1) subfamily of nuclear hormone receptors (NRs) has been implicated in Parkinson's disease, schizophrenia, manic depression, atherogenesis, Alzheimer's disease, rheumatoid arthritis, cancer and apoptosis. This has driven investigations into the mechanism of action, and the identification of small molecule regulators, that may provide the platform for pharmaceutical and therapeutic exploitation. Recently, we found that the purine antimetabolite 6-Mercaptopurine (6-MP), which is widely used as an anti-neoplastic and anti-inflammatory drug, modulated the NR4A1-3 subfamily. Interestingly, the agonist-mediated activation did not involve modulation of primary coactivators' (e.g. p300 and SRC-2/GRIP-1) activity and/or recruitment. However, the role of the subsequently recruited coactivators, for example CARM-1 and TRAP220, in 6-MP-mediated activation of the NR4A1-3 subfamily remains obscure. In this study we demonstrate that 6-MP modulates the activity of the coactivator TRAP220 in a dose-dependent manner. Moreover, we demonstrate that TRAP220 potentiates NOR-1-mediated transactivation, and interacts with the NR4A1-3 subgroup in an AF-1-dependent manner in a cellular context. The region of TRAP220 that mediated 6-MP activation and NR4A interaction was delimited to amino acids 1-800, and operates independently of the critical PKC and PKA phosphorylation sites. Interestingly, TRAP220 expression does not increase the relative induction by 6-MP, however the absolute level of NOR-1-mediated trans-activation is increased. This study demonstrates that 6-MP modulates the activity of the NR4A subgroup, and the coactivator TRAP220.

Antibiotic susceptibilities of Pseudomonas aeruginosa isolates derived from patients with cystic fibrosis under aerobic, anaerobic, and biofilm conditions

Recent studies have determined that Pseudomonas aeruginosa can live in a biofilm mode within hypoxic mucus in the airways of patients with cystic fibrosis (CF). P. aeruginosa grown under anaerobic and biofilm conditions may better approximate in vivo growth conditions in the CF airways, and combination antibiotic susceptibility testing of anaerobically and biofilm-grown isolates may be more relevant than traditional susceptibility testing under planktonic aerobic conditions. We tested 16 multidrug-resistant isolates of P. aeruginosa derived from CF patients using multiple combination bactericidal testing to compare the efficacies of double and triple antibiotic combinations against the isolates grown under traditional aerobic planktonic conditions, in planktonic anaerobic conditions, and in biofilm mode. Both anaerobically grown and biofilm-grown bacteria were significantly less susceptible (P < 0.01) to single and combination antibiotics than corresponding aerobic planktonically grown isolates. Furthermore, the antibiotic combinations that were bactericidal under anaerobic conditions were often different from those that were bactericidal against the same organisms grown as biofilms. The most effective combinations under all conditions were colistin (tested at concentrations suitable for nebulization) either alone or in combination with tobramycin (10 mu g ml(-1)), followed by meropenem combined with tobramycin or ciprofloxacin. The findings of this study illustrate that antibiotic sensitivities are dependent on culture conditions and highlight the complexities of choosing appropriate combination therapy for multidrug-resistant P. aeruginosa in the CF lung.

Is Lactobacillus rhamnosus GG effective in preventing the onset of antibiotic-associated diarrhoea: A systematic review

Objective: To evaluate the efficacy of Lactobacillus rhamnosus GG in the prevention of antibiotic-associated diarrhoea. Data Sources: A computer-based search of MED-LINE, CINAHL, AMED, the Cochrane Controlled Trials Register and the Cochrane Database of Systematic Reviews was conducted. A hand-search of the bibliographies of relevant papers and previous meta-analyses was undertaken. Review Methods: Trials were included in the review if they compared the effects of L. rhamnosus GG and placebo and listed diarrhoea as a primary end-point. Studies were excluded if they were not placebo-controlled or utilised other probiotic strains. Results:Six trials were found that met all eligibility requirements. Significant statistical heterogeneity of the trials precluded meta-analysis. Four of the six trials found a significant reduction in the risk of antibiotic-associated diarrhoea with co-administration of Lactobacillus GG. One of the trials found a reduced number of days with antibiotic-induced diarrhoea with Lactobacillus GG administration, whilst the final trial found no benefit of Lactobacillus GG supplementation. Conclusion: Additional research is needed to further clarify the effectiveness of Lactobacillus GG in the prevention of antibiotic-associated diarrhoea. Copyright (c) 2005 S. Karger AG, Basel.

Antibiotic resistance in the intensive care unit: A primer in bacteriology

The clinical use of potent, well-tolerated, broad-spectrum antibiotics has been paralleled by the development of resistance in bacteria, and the prevalence of highly resistant bacteria in some intensive care units is despairingly commonplace. The intensive care community faces the realistic prospect of untreatable nosocomial infections and should be searching for new approaches to diagnose and manage resistant bacteria. In this review, we discuss some of the relevant underlying biology, with a particular focus on genetic transfer vehicles and the relationship of selection pressure to their movements. It is an attempt to demystify the relevant language and concepts for the anaesthetist and intensivist, to explain some of the reasons for the emergence of resistance in bacteria, and to provide a contextual basis for discussion of management approaches such as selective decontamination and antibiotic cycling.

A DHA14 drug efflux gene from Xanthomonas albilineans confers high-level albicidin antibiotic resistance in Escherichia coli

Aims: Identification of a gene for self-protection from the antibiotic-producing plant pathogen Xanthomonas albilineans, and functional testing by heterologous expression. Methods and Results: Albicidin antibiotics and phytotoxins are potent inhibitors of prokaryote DNA replication. A resistance gene (albF) isolated by shotgun cloning from the X. albilineans albicidin-biosynthesis region encodes a protein with typical features of DHA14 drug efflux pumps. Low-level expression of albF in Escherichia coli increased the MIC of albicidin 3000-fold, without affecting tsx-mediated albicidin uptake into the periplasm or resistance to other tested antibiotics. Bioinformatic analysis indicates more similarity to proteins involved in self-protection in polyketide-antibiotic-producing actinomycetes than to multi-drug resistance pumps in other Gram-negative bacteria. A complex promoter region may co-regulate albF with genes for hydrolases likely to be involved in albicidin activation or self-protection. Conclusions: AlbF is the first apparent single-component antibiotic-specific efflux pump from a Gram-negative antibiotic producer. It shows extraordinary efficiency as measured by resistance level conferred upon heterologous expression. Significance and Impact of the Study: Development of the clinical potential of albicidins as potent bactericidial antibiotics against diverse bacteria has been limited because of low yields in culture. Expression of albF with recently described albicidin-biosynthesis genes may enable large-scale production. Because albicidins are X. albilineans pathogenicity factors, interference with AlbF function is also an opportunity for control of the associated plant disease.

Predictors of an antibiotic prescription by GPs for respiratory tract infections: a pilot

Background. Antibiotics are over-prescribed for respiratory tract infections in Australia. Objectives. The aim of this study was to describe the clinical predictors of GPs' prescribing of antibiotics. Methods. We used Clinical Judgment Analysis to study the responses of GPs to hypothetical paper-based vignettes of a 20-year-old with a respiratory tract infection. The nature of four symptoms and signs (colour of nasal mucous discharge; soreness of the throat; presence of fever; and whether any cough was productive of sputum) was varied and their effect on prescribing measured using logistic regression. Results. Twenty GPs participated. The nature of each symptom and sign significantly predicted prescribing of an antibiotic. Cough productive of yellow sputum; presence of sore throat; fever; and coloured nasal mucus increased the probability of an antibiotic being prescribed. Conclusions. GPs are influenced by clinical signs and symptoms to use antibiotics for respiratory infections for which there is poor evidence of efficacy from the literature.

Hospital pharmacists' awareness of a new antibiotic guideline in the UK:implications for practice

Objectives: Pharmacists play an important role in the review of local hospital guidelines. British Thoracic Society (BTS) guidelines for the management of patients with community-acquired pneumonia (CAP) were updated in 2001, and it is important that individual hospital recommendations are based upon this national guidance. The aim of this study was to identify UK Chief Pharmacists' awareness of these updated guidelines one year after their publication. Secondary aims were to identify whether pharmacists had subsequently initiated revision of institutional CAP guidelines, and what roles different professional staff had performed in this process. Method: A self-completion postal questionnaire was sent to the Chief Pharmacist (or their nominated staff) in 253 UK NHS hospitals in November 2002. This aimed to identify issues relating to their awareness of the 2001 BTS guidelines and subsequent revision of their hospital's guidelines. Results:188 questionnaires were returned (a response rate of 74%), of which 164 hospitals had local antibiotic prescribing guidelines. Respondents in 29% of these hospitals were unaware of the 2001 BTS publication and institutional guidelines had been revised in only 51% of hospitals where the Chief Pharmacist was purportedly aware of the new BTS guidance. Generally, more staff types were involved in revising guidelines than initiating revision. Conclusions:Variability existed in both Chief Pharmacists' awareness of new national guidance and subsequent review processes operating in individual hospitals. A lack of proactive reaction to new national guidance was identified in some hospitals, and it is hoped that the establishment of specialist "infectious diseases pharmacists" will facilitate the review of institutional antibiotic prescribing guidelines in the future. © Springer 2005.

Development of a prescribing indicator for objective quantification of antibiotic usage in secondary care

Objectives: To compare the recognized defined daily dose per 100 bed-days (DDD/100 bed-days) measure with the defined daily dose per finished consultant episode (DDD/FCE) in a group of hospitals with a variety of medicines management strategies. To compare antibiotic usage using the above indicators in hospitals with and without electronic prescribing systems. Methods: Twelve hospitals were used in the study. Nine hospitals were selected and split into three cohorts (three high-scoring, three medium-scoring and three low-scoring) by their 2001 medicines management self-assessment scores (MMAS). An additional cohort of three electronic prescribing hospitals was included for comparison. MMAS were compared to antibiotic management scores (AMS) developed from a questionnaire relating specifically to control of antibiotics. FCEs and occupied bed-days were obtained from published statistics and statistical analyses of the DDD/100 bed-days and DDD/FCE were carried out using SPSS. Results: The DDD/100 bed-days varied from 81.33 to 189.37 whilst the DDD/FCE varied from 2.88 to 7.43. The two indicators showed a high degree of correlation with r = 0.74. MMAS were from 9 to 22 (possible range 0-23) and the AMS from 2 to 13 (possible range 0-22). The two scores showed a high degree of correlation with r = 0.74. No correlation was established between either indicator and either score. Conclusions: The WHO indicator for medicines utilization, DDD/100 bed-days, exhibited the same level of conformity as that exhibited from the use of the DDD/FCE indicating that the DDD/FCE is a useful additional indicator for identifying hospitals which require further study. The MMAS can be assumed to be an accurate guide to antibiotic medicines management controls. No relationship has been found between a high degree of medicines management control and the quantity of antibiotic prescribed. © The British Society for Antimicrobial Chemotherapy; 2004 all rights reserved.

Documentation of antibiotic prescribing controls in UK NHS hospitals

Objectives: To identify the types, prevalence and nature of antibiotic prescribing control documents within NHS hospitals in the UK. Methods: A self-completion postal questionnaire was sent to each Chief Pharmacist at 465 NHS hospitals in 2001/2002. This contained questions covering hospital demographics, and hospital antibiotic prescribing control documentation, including format, dissemination, approval and review processes. Results: In total, 253 (54%) completed questionnaires were returned. Of these, 168 respondents' hospitals had an antibiotic formulary, 107 had a policy for antibiotic prescribing and 216 had guidelines on antibiotic use. All three types of antibiotic prescribing documents were used by 82 hospitals but 18 did not have any documents; 44% of formularies, 45% of policies and 35% of guidelines were available electronically. The Drug and Therapeutics Committee was the most frequently cited body for document approval and approximately one-third of documents had been approved during the current year of the questionnaire. Only about one-half of responding hospitals had an annual review of documents. Conclusions: Despite publication of high-profile national guidance in response to growing concerns regarding antimicrobial resistance, there has been little increase in the use of antibiotic prescribing control documents in NHS hospitals over the past decade. It is clear that appropriate controls for antibiotic prescribing are not yet universally applied in the UK and recommendations for action have been proposed. © The British Society for Antimicrobial Chemotherapy 2004; all rights reserved.