Effects of oral probiotic supplements on vaginal microbiota during pregnancy: a randomised, double-blind, placebo-controlled trial with microbiome analysis.

OBJECTIVE: To determine the effects on the vaginal microbiota of an oral probiotic preparation administered from early pregnancy. DESIGN: Randomised, double blind, placebo-controlled trial. SETTING: Four maternity units in the UK. POPULATION: Women aged 16 years or older recruited at 9-14 weeks' gestation. METHODS: Participants were randomly allocated to receive oral capsules of probiotic containing Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 each at 2.5 × 109 colony-forming units (CFUs) or placebo once daily from recruitment until the end of pregnancy. MAIN OUTCOME MEASURE: Rates of bacterial vaginosis (BV, defined as Nugent score ≥7) at 18-20 weeks' gestation compared by logistic regression adjusted for possible confounders. RESULTS: The primary analysis included 78% (238/304) of participants who initially consented (probiotic group 123, placebo group 115). Of these participants, 95% (227/238) reported an intake of 93% or more of the required number of capsules. The rates of BV did not differ between groups at 18-20 weeks' gestation (15% (19/123) in the probiotic group vs. 9% (10/115) in the placebo group, adjusted odds ratio 1.82, 95% confidence interval 0.64-5.19). There were also no differences between the groups in the proportion of women colonised with the probiotic strains, Escherichia coli, group B streptococci or other vaginal microbiota. There were no differences in the alpha diversity or composition of the bacterial communities between or within the probiotic and placebo groups at 9-14 and 18-20 weeks' gestation. CONCLUSIONS: Oral probiotics taken from early pregnancy did not modify the vaginal microbiota. TWEETABLE ABSTRACT: The oral probiotic preparation used in this study does not prevent BV in pregnant women.

Multicenter performance evaluation of the Unyvero IAI cartridge for detection of intra-abdominal infections.

Intra-abdominal infections (IAIs) are one of the most common type of infections in patients with sepsis and an important cause of death in intensive care units. Early detection and treatment are necessary to reduce patient complications and improve outcomes. The Unyvero IAI Application (Curetis GmbH) is the first automated assay to rapidly and simultaneously identify a large panel of bacteria, fungi, toxins, and antibiotic resistance markers directly from IAI-related samples. The assay was evaluated in four European clinical laboratories in comparison to routine microbiological practices. A total of 300 clinical samples were tested with an overall sensitivity of 89.3% and specificity of 99.5%, while time to results was reduced by an average of about 17 h compared to identification (ID) results and 41 h compared to full antibiotic susceptibility testing (AST) results. The Unyvero IAI was able to detect additional microorganisms compared with culture, in particular anaerobes, with most detections confirmed by sequencing. The most frequent resistance markers detected were mecA/mecC (n = 25), aacA4 (n = 20), and blaCTX-M (n = 17) and carbapenemase genes were identified in nine specimens. Further studies are now required to determine the clinical impact of this new rapid test which could play a role in the successful treatment of IAI.

Diversity and stability of cultured vaginal lactobacilli in pregnant women from a multi-ethnic urban UK population.

AIM: To determine the diversity and stability of cultured vaginal lactobacilli in a multi-ethnic population of pregnant women. METHODS AND RESULTS: A single-centre, prospective, cohort study was performed in a tertiary perinatal centre in East London, UK. Self-collected vaginal swabs at 13 and 20 weeks gestation were obtained from women attending for routine antenatal care and cultured for lactobacilli. In women who provided both swabs, 37 of 203 (18%) had no lactobacilli cultured at either time. Only 53 (26%) had the same species at both times. Black women were less likely to have lactobacilli cultured at 13 weeks (P = 0·014), and Black and Asian women were less likely to have lactobacilli cultured at 20 weeks (P = 0·002) compared with those in the White and Other groups. CONCLUSIONS: Significant differences exist between ethnic groups in the carriage and stability of vaginal lactobacilli. SIGNIFICANCE AND IMPACT OF THE STUDY: These differences have implications for the design of interventions aimed at normalizing the vaginal microbiota in pregnant women.

Matrix-assisted laser desorption/ionisation-time of flight mass spectrometry: rapid identification of bacteria isolated from patients with cystic fibrosis.

Despite extensive research into the diagnosis and management of cystic fibrosis (CF) over the past decades, sufferers still have a median life expectancy of less than 37 years. Respiratory tract infections have a significant role in increasing the morbidity and mortality of patients with CF via a progressive decline in lung function. Rapid identification of organisms recovered from CF sputum is necessary for effective management of respiratory tract infections; however, standard techniques of identification are slow, technically demanding and expensive. The aim of this study is to asses the suitability of matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS) in identifying bacteria isolated from the respiratory tract of patients with CF, and is assessed by testing the accuracy of MALDI-TOF MS in identifying samples from a reference collection of rare CF strains in conjunction with comparing MALDI-TOF MS and standard techniques in identifying clinical isolates from sputum samples of CF patients. MALDI-TOF MS accurately identified 100% of isolates from the reference collection of rare CF pathogens (EuroCare CF collection). The isolate identification given by MALDI-TOF MS agreed with that given by standard techniques for 479/481 (99.6%) clinical isolates obtained from respiratory samples provided by patients with CE In two (0.4%) of 481 samples there was a discrepancy in identification between MALDI-TOF MS and standard techniques. One organism was identified as Pseudomonas aeruginosa by MALDI-TOF but could only be identified by the laboratory's standard methods as of the Pseudomonas genus. The second organism was identified as P. beteli by MALDI-TOF MS and Stenotrophomonas maltophilia by standard methods. This study shows that MALDI-TOF MS is superior to standard techniques in providing cheap, rapid and accurate identification of CF sputum isolates.

Rapid identification of bacteria from bioMérieux BacT/ALERT blood culture bottles by MALDI-TOF MS.

Several studies have reported poor results when trying to identify microorganisms directly from the bioMérieux BacT/ALERT blood culture system using matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry. The aim of this study is to evaluate two new methods, Sepsityper and an enrichment method for direct identification of microorganisms from this system. For both methods the samples were processed using the Bruker Microflex LT mass spectrometer (Biotyper) using the Microflex Control software to obtain spectra. The results from direct analysis were compared with those obtained by subculture and subsequent identification. A total of 350 positive blood cultures were processed simultaneously by the two methods. Fifty-three cultures were polymocrobial or failed to grow any organism on subculture, and these results were not included as there was either no subculture result, or for polymicrobial cultures it was known that the Biotyper would not be able to distinguish the constituent organisms correctly. Overall, the results showed that, contrary to previous reports, it is possible to identify bacteria directly from bioMérieux blood culture bottles, as 219/297 (74%) correct identifications were obtained using the Bruker Sepsityper method and 228/297 (77%) were obtained for the enrichment method when there is only one organism was present. Although the enrichment method was simpler, the reagent costs for the Sepsityper method were approximately pound 4.00 per sample compared to pound 0.50. An even simpler and cheaper method, which was less labour-intensive and did not require further reagents, was investigated. Seventy-seven specimens from positive signalled blood cultures were analysed by inoculating prewarmed blood agar plates and analysing any growth after 1-, 2- and 4-h periods of incubation at 37 degrees C, by either direct transfer or alcohol extraction. This method gave the highest number of correct identifications, 66/77 (86%), and was cheaper and less labour-intensive than either of the two above methods.

The emergence of qnr-mediated quinolone resistance among Enterobacteriaceae in Jamaica.

OBJECTIVE: Quinolone resistance is usually caused by various chromosomal mutations, but has been more recently associated with plasmids which carry the qnr determinant. The aim of this study is to investigate the prevalence of qnr genes in clinical isolates of Enterobacteriaceae in Jamaica. METHODS: A total of 255 non-duplicate fluoroquinolone-resistant Enterobacteriaceae clinical isolates, comprising 232 Escherichia coli, 20 Klebsiella species and three Enterobacter spp were collected between October 2007 and November 2008 from hospitalized patients in Jamaica. The presence of the qnr gene was screened by PCR using specific primers for qnrA, qnrB and qnrS in extracted plasmid DNA. RESULTS: Eighty-three (32.5%) of these isolates were qnr-positive, of which 47.0% housed the qnrA gene only, 1.2% qnrB and 9.6% qnrS only. Another 36.1% possessed both qnrA and qnrS genes. Approximately 30% of the quinolone-resistant E coli isolates harboured the qnr gene while 50% Klebsiella spp and all Enterobacter spp were positive. CONCLUSION: The emergence of qnr-mediated quinolone resistance among clinical Enterobacteriaceae isolates is described for the first time in Jamaica.

A point prevalence study to determine the inpatient rate of carbapenemase-producing organisms at a large London NHS Trust.

BACKGROUND: There has been an increase in the number of carbapenemase-producing organisms documented across the UK over the past 10 years. From these, the 'big five' carbapenemases (KPC, OXA-48, IMP, VIM, and NDM) are the most common types reported in the order Enterobacterales, identified from a variety of reactive screening, outbreak, inpatient surveillance, and diagnostic samples. AIM: To perform a point prevalence study to determine the inpatient carriage rate of carbapenemase-producing organisms at Barts Health NHS Trust, which encompasses 2.5 million patients across four London boroughs: Tower Hamlets, Newham, Redbridge, and Waltham Forest. METHODS: Rectal swabs were collected from consenting inpatients, alongside details of the ward's medical specialty, patient's country of birth, history of foreign travel, length of hospitalization, and history of prior hospitalization. Swabs were enriched and subcultured on to mSuperCARBA selective medium. All Enterobacterales, Acinetobacter, and Pseudomonas species were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy and underwent antibiotic susceptibility testing by disc diffusion, according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. All isolates were screened for the 'big five' carbapenemases using a modified version of a published reverse transcriptase-polymerase chain reaction assay. FINDINGS: Of the 977 inpatients tested, 35 CPOs were isolated from 30 patients. NDM was the most frequently detected carbapenemase, followed by OXA-48, with an overall prevalence of 3.1%. Organisms isolated included Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, and Escherichia coli. Renal and elderly care patients had the highest prevalences of CPOs, whereas the intensive care unit prevalence was low. Statistical analysis found that hospitalization abroad, any previous hospitalization, foreign travel and, specifically, travel to India, Pakistan, and Bangladesh were associated with increased risk of CPO carriage. CONCLUSION: The overall prevalence of CPOs at Barts Health Trust was 3.1%, comprising NDM and OXA-48-type carbapenemases, which is in line with other London-based studies. Renal patients and the elderly had the highest burden of CPOs, whereas previous hospitalization and foreign travel were associated with an increased risk of CPO carriage.

Do probiotics prevent antibiotic-associated diarrhoea? Results of a multicentre randomized placebo-controlled trial.

BACKGROUND: Antibiotic-associated diarrhoea (AAD) is a side-effect of antibiotic consumption and probiotics have been shown to reduce AAD. METHODS: A multicentre, double-blind, placebo-controlled, randomized trial was conducted to evaluate the role of Lactobacillus casei DN114001 (combined as a drink with two regular yoghurt bacterial strains) in reducing AAD and Clostridioides difficile infection in patients aged over 55 years. The primary outcome was the incidence of AAD during 2 weeks of follow-up. RESULTS: A total of 1127 patients (mean age ± standard deviation: 73.6 ± 10.5) were randomized to the active group (N = 549) or placebo group (N = 577). Both groups were followed up as per protocol. The proportion of patients experiencing AAD during follow-up was 19.3% (106/549) in the probiotic group vs 17.9% (103/577) in the placebo group (unadjusted odds ratio 1.10, 95% confidence interval 0.82-1.49, P = 0.53). CONCLUSIONS: No significant evidence was found of a beneficial effect of the specific probiotic formulation in preventing AAD in this elderly population drawn from a number of different UK hospitals. However, in the UK and in many other healthcare systems there have, in recent years, been many changes in antibiotic stewardship policies, an overall decrease in incidence in C. difficile infection, as well as an increased awareness of infection prevention, and modifications in nursing practice. In light of these factors, it is impossible to conclude definitively from the current trial that the study-specific probiotic formulation has no role in preventing AAD, and it is our view that further trials may be indicated, controlling for these variables.

Community prevalence of carbapenemase-producing organisms in East London.

BACKGROUND: Over the last decade there has been a rapid, worldwide increase in carbapenem resistance, which is of growing concern. The main protagonists, the carbapenemases Klebsiella pneumoniae carbapenemase (KPC), oxacillinase ß-lactamase 48 (OXA-48), imipenemase metallo-ß-lactamase (IMP), Verona integron-borne metallo-ß-lactamase (VIM), and New Delhi metallo-ß-lactamase (NDM) have also been reported across the UK. However, these reports are derived from a combination of reactive screening, outbreak control, inpatient surveillance, and diagnostic samples. Therefore, the true community prevalence is unknown. AIM: To determine the community prevalence of carbapenemase-producing organisms (CPOs) in the area served by Barts Health NHS Trust. METHODS: Active screening of 200 non-duplicate community stool samples was performed. Patient demographics and foreign travel history were extracted from the laboratory information management system to identify potential risk factors for carriage of CPOs. FINDINGS: Patients in this study were aged from one to 93 years and were evenly distributed between male and female. Foreign travel in the last year was listed for 46 out of 200 (23%) patients, with the most commonly visited countries including Bangladesh (4%), India (2.5%), Morocco (2%), and Turkey (1.5%). However, only one patient tested positive for a CPO, an NDM-producing Pseudomonas aeruginosa, and this patient had travelled to the Caribbean. CONCLUSION: To date, there have been no studies investigating the prevalence of CPOs in the UK community. Given the high-risk patient population served by Barts Health NHS Trust, it is reassuring that the prevalence observed here was low. However, it should be highlighted that travel to countries not previously categorized as high risk may also pose a threat.

A service evaluation of simultaneous near-patient testing for influenza, respiratory syncytial virus, Clostridium difficile and norovirus in a UK district general hospital.

BACKGROUND: The Cepheid® GeneXpert® (GXP) can simultaneously test for norovirus (NV), Clostridium difficile (CD), influenza A/B (IFA/B) and respiratory syncytial virus (RSV). AIM: To compare centralized multiplex polymerase chain reaction (PCR) testing with localized GXP testing at a district general hospital. METHODS: From December 2017 to December 2018, samples received at Whipps Cross University Hospital (WCUH) were first tested at the local laboratory before transport centrally to the Royal London Hospital (RLH). At the RLH, a non-proprietary multiplex reverse transcriptase (RT) PCR assay was performed, which also tested for gastrointestinal or respiratory pathogens not tested for by the GXP. FINDINGS: A total of 1111 stool and respiratory samples were processed at both sites; 591 were respiratory and 520 were stool samples. Compared to centralized testing, the GXP gave sensitivity, specificity, and NPV all in excess of 97%, with the exception of RSV. The RSV assay had a sensitivity of 66.7% (95% confidence interval (CI) 24.1, 94.0) but an NPV of 99.7% (95% CI 98.6, 99.9). At the RLH, 65 (5.9%) additional respiratory or gastrointestinal viruses were detected, predominantly rhinovirus 35 (3.2%) and adenovirus 11 (1.0%). Compared to centralized testing, the median time saved for local respiratory and gastrointestinal sample testing was 19 h and 46 min and 17 h and 6 min, respectively. CONCLUSIONS: Local GXP testing compared to centralized multiplex PCR testing for IF, NV and CD, demonstrated sensitivities, specificities and NPV between 95% and 100%. Turnaround times were faster, enabling quicker infection prevention and control decision making. In our local setting (WCUH), the GXP demonstrated the potential to reduce NV and IFA/B outbreaks.

Insights into possibilities for grouping and read-across for nanomaterials in EU chemicals legislation.

This paper presents a comprehensive review of European Union (EU) legislation addressing the safety of chemical substances, and possibilities within each piece of legislation for applying grouping and read-across approaches for the assessment of nanomaterials (NMs). Hence, this review considers both the overarching regulation of chemical substances under REACH (Regulation (EC) No 1907/2006 on registration, evaluation, authorization, and restriction of chemicals) and CLP (Regulation (EC) No 1272/2008 on classification, labeling and packaging of substances and mixtures) and the sector-specific pieces of legislation for cosmetic, plant protection and biocidal products, and legislation addressing food, novel food, and food contact materials. The relevant supporting documents (e.g. guidance documents) regarding each piece of legislation were identified and reviewed, considering the relevant technical and scientific literature. Prospective regulatory needs for implementing grouping in the assessment of NMs were identified, and the question whether each particular piece of legislation permits the use of grouping and read-across to address information gaps was answered.

Molecular diagnosis of vascular access device-associated infection in children being treated for cancer or leukaemia.

Blood samples were collected for quantitative 16S rDNA analysis from the vascular access device (VAD) of patients presenting with fever at participating centres of the UK Children's Cancer and Leukaemia Group. In total, 260 of 301 episodes of fever were evaluable and were classified as probable, possible, unlikely or unclassifiable VAD-associated infection. The sensitivity of the 16S rDNA assay declined concomitantly with delays from time of presentation to sampling. The sensitivity with >0.125 pg of bacterial DNA/microL of whole blood was 80% for the 20 probable VAD-associated infections diagnosed with samples collected on the day of or day following presentation. The specificity rose with increasing amounts of bacterial DNA, from 93% with >0.125 pg, to 98% with 0.25-0.5 pg, and to 100% with >0.5 pg/microL blood. The positive predictive value (for probable or possible) was 88% (95% CI 70-98%) with 0.25 pg/microL, and 100% (95% CI 83-100%) with >0.5 pg/microL. All 18 (6.8%) episodes with >0.5 pg of bacterial DNA/microL blood were associated with positive blood cultures. Identifications derived from the DNA sequence were consistent with the blood culture identifications for 15 of the 17 episodes with a DNA sequence identification. The VAD was removed because of suspected infection in six (2.8%) of 216 episodes with <0.125 pg of bacterial DNA/microL, in one (5%) of 20 episodes with 0.125-0.25 pg/microL, in one (16.7%) of six episodes with 0.25-0.5 pg/microL, and in nine (50%) of 18 episodes with >0.5 pg/microL. A bacterial DNA concentration of >0.5 pg/microL in blood drawn through a central venous catheter at the time of fever presentation had a high positive predictive value for VAD-associated infection and predicted an increased risk of VAD removal because of suspected infection.

Optimal detection of carbapenemase-producing Enterobacteriaceae from rectal samples: a role for enrichment?

BACKGROUND: Successful laboratory detection of carbapenemase-producing Enterobacteriaceae (CPE) in patient surveillance samples is a diagnostic challenge. In the absence of a reference standard for screening rectal swabs for CPE, many phenotypic, genotypic, culture- and non-culture-based assays have been proposed for identifying these bacteria. AIM: To develop and optimize a CPE screening protocol capable of identifying all frequently encountered CPE, including those producing OXA-48-like carbapenemases. METHODS: Faropenem susceptibility testing was performed on 507 presumptive CPE isolated from diagnostic samples and CPE rectal screens between March and August 2016. Results from this CPE screening method were compared to those from direct culture on mSuperCARBA™, temocillin enrichment culture, and use of an antibiotic resistance algorithm, to determine the optimal method to employ in the detection of CPE. FINDINGS: Faropenem was a poor predictor of carbapenemase production (58% true positives). The combination of a temocillin enrichment stage and interpretive reading of antibiotic resistance phenotypes improved the recovery and identification of CPE significantly (91% true positives), especially for OXA-48 producers (P = 0.03). CONCLUSION: The combination of temocillin enrichment, a selective chromogenic medium, and an antibiotic resistance-based algorithm significantly improved the detection of all CPE recovered from routine and targeted surveillance samples.

The detection of microbial DNA but not cultured bacteria is associated with increased mortality in patients with suspected sepsis-a prospective multi-centre European observational study.

OBJECTIVES: Blood culture results inadequately stratify the mortality risk in critically ill patients with sepsis. We sought to establish the prognostic significance of the presence of microbial DNA in the bloodstream of patients hospitalized with suspected sepsis. METHODS: We analysed the data collected during the Rapid Diagnosis of Infections in the Critically Ill (RADICAL) study, which compared a novel culture-independent PCR/electrospray ionization-mass spectrometry (ESI-MS) assay with standard microbiological testing. Patients were eligible for the study if they had suspected sepsis and were either hospitalized or were referred to one of nine intensive care units from six European countries. The blood specimen for PCR/ESI-MS assay was taken along with initial blood culture taken for clinical indications. RESULTS: Of the 616 patients recruited to the RADICAL study, 439 patients had data on outcome, results of the blood culture and PCR/ESI-MS assay available for analysis. Positive blood culture and PCR/ESI-MSI result was found in 13% (56/439) and 40% (177/439) of patients, respectively. Either a positive blood culture (p 0.01) or a positive PCR/ESI-MS (p 0.005) was associated with higher SOFA scores on enrolment to the study. There was no difference in 28-day mortality observed in patients who had either positive or negative blood cultures (35% versus 32%, p 0.74). However, in patients with a positive PCR/ESI-MS assay, mortality was significantly higher in comparison to those with a negative result (42% versus 26%, p 0.001). CONCLUSIONS: Presence of microbial DNA in patients with suspected sepsis might define a patient group at higher risk of death.

Anaerobic sepsis due to multidrug-resistant Bacteroides fragilis: microbiological cure and clinical response with linezolid therapy.

We describe the first reported case of anaerobic sepsis due to Bacteroides fragilis with simultaneous resistance to metronidazole, beta-lactams, beta lactam/beta-lactamase inhibitors, carbapenems, macrolides, and tetracyclines. Microbiological cure and clinical improvement was achieved with linezolid therapy, an agent that may be useful for the treatment of multidrug-resistant anaerobic infections.

Acidified nitrite as a potential antifungal agent.

The use of acidified nitrite as a potential antifungal agent was investigated by exposing clinical isolates of Candida albicans, Candida glabrata, Candida tropicalis, Cryptococcus neoformans, Aspergillus fumigatus and Rhodotorula to varying concentrations of acidified nitrite at different pH levels to determine the minimal fungicidal concentration after 10 min exposure.

Competition between methicillin-sensitive and -resistant Staphylococcus aureus in the anterior nares.

Colonization of the anterior nares with Staphylococcus aureus has been shown to be a risk factor for infection. The purpose of this study was to test the hypothesis that methicillin-resistant strains of S. aureus (MRSA) compete with methicillin-sensitive (MSSA) strains for colonization of the anterior nares. As part of the local National Health Service trust MRSA infection control strategy, patients who have been in a healthcare institution in the last year are routinely sampled and tested for MRSA colonization at the time of hospital admission. The sampling and testing methods were modified for the six-month period of this study to allow the detection of both MSSA and MRSA/MSSA co-colonization. MRSA alone was carried by 56 (8%) of 680 patients, MSSA alone by 115 patients (17%), 505 patients (74.3%) carried neither, and four patients (0.6%) carried both MRSA and MSSA. The deviance between the observed number of co-colonized swabs and that expected under the null hypothesis of no competition between MSSA and MRSA was significant (P=0.02, Fisher's exact test). The statistical approach is unaffected by the confounding effect of factors that affect the relative frequencies of MRSA or MSSA colonization. When logistic regression was used to estimate the extent of competition, controlling for effects of age and sex, we estimated a protective efficacy of MSSA colonization in the prevention of MRSA colonization of 78% (95% CI 29-99%). Results from this cross-sectional study support the hypothesis that MRSA and MSSA compete for colonization space, and provides an estimate of the extent to which MSSA interferes with MRSA colonization.

White paper on the promotion of an integrated risk assessment concept in European regulatory frameworks for chemicals.

The vision of a sustainable and safe use of chemicals to protect human health, preserve the environment and maintain the ecosystem requires innovative and more holistic approaches to risk assessment (RA) in order to better inform decision making. Integrated risk assessment (IRA) has been proposed as a solution to current scientific, societal and policy needs. It is defined as the mutual exploitation of environmental risk assessment (ERA) for human health risk assessment (HHRA) and vice versa in order to coherently and more efficiently characterize an overall risk to humans and the environment for better informing the risk analysis process. Extrapolating between species which are relevant for HHRA and ERA requires a detailed understanding of pathways of toxicity/modes of action (MoA) for the various toxicological endpoints. Significant scientific advances, changes in chemical legislation, and increasing environmental consciousness have created a favourable scientific and regulatory environment to develop and promote the concept and vision of IRA. An initial proof of concept is needed to foster the incorporation of IRA approaches into different chemical sectorial regulations and demonstrate their reliability for regulatory purposes. More familiarity and confidence with IRA will ultimately contribute to an overall reduction in in vivo toxicity testing requirements. However, significant progress will only be made if long-term support for MoA-related research is secured. In the short term, further exchange and harmonization of RA terminology, models and methodologies across chemical categories and regulatory agencies will support these efforts. Since societal values, public perceptions and cultural factors are of increasing importance for the acceptance of risk analysis and successful implementation of risk mitigation measures, the integration of socio-economic analysis and socio-behavioural considerations into the risk analysis process may help to produce a more effective risk evaluation and consideration of the risks and benefits associated with the use of chemicals.

A group II intron in a conjugative transposon from the gram-positive bacterium, Clostridium difficile.

We have been studying the conjugative transposon Tn5397, originally isolated from the Gram-positive pathogen Clostridium difficile. Physical analysis of this transposon demonstrated that it contained a group II intron. This is the first report of an intron in a conjugative transposon and the first report of a group II intron in Gram-positive bacteria. The intron interrupted a gene in Tn5397 that is almost identical to orf14 from Tn916. DNA hybridisation analysis showed that elements related to Tn5397, containing the group II intron, were present in five other C. difficile strains from different geographical locations suggesting that the element is likely to be widely distributed.