Novel scores relevant to antimicrobial resistance and hospital-acquired infections developed with data from a multi-hospital consortium in the Parisian region of France.

PURPOSE: Indicators for comparing and understanding differences in antimicrobial resistance (AMR) and healthcare-associated infections (HAIs) for benchmarking are essential to identify priorities for hospitals. METHODS: This study measured the incidence of hospital-acquired or resistant Gram-negative bacilli bloodstream infections (GNB-BSIs) in a large public healthcare consortium in the Parisian region of France. RESULTS: Within each hospital, there was a strong positive correlation between the incidence of GNB-BSIs due to resistant GNB and the incidence of hospital-acquired GNB-BSIs. Two scores measuring AMR and HAI rates by combining different GNB-BSI incidence rates were developed as indicators. These scores were highly variable within the hospital consortium. On multi-variate analysis, AMR and HAI scores were significantly associated with the proportion of surgical beds, staff absenteeism and the consumption of alcohol-based hand rub, with the latter two characteristics being amenable to interventions. Carbapenem use was also linked to AMR, but this may be because carbapenems are the preferred drug for treating resistant infections. CONCLUSION: These results shed light on the incidence of HAIs and AMR in the study hospitals, and suggest possibilities for targeted interventions at healthcare facility level.

Silent gene clusters encode magnetic organelle biosynthesis in a non-magnetotactic phototrophic bacterium.

Horizontal gene transfer is a powerful source of innovations in prokaryotes that can affect almost any cellular system, including microbial organelles. The formation of magnetosomes, one of the most sophisticated microbial mineral-containing organelles synthesized by magnetotactic bacteria for magnetic navigation in the environment, was also shown to be a horizontally transferrable trait. However, the mechanisms determining the fate of such genes in new hosts are not well understood, since non-adaptive gene acquisitions are typically rapidly lost and become unavailable for observation. This likely explains why gene clusters encoding magnetosome biosynthesis have never been observed in non-magnetotactic bacteria. Here, we report the first discovery of a horizontally inherited dormant gene clusters encoding biosynthesis of magnetosomes in a non-magnetotactic phototrophic bacterium Rhodovastum atsumiense. We show that these clusters were inactivated through transcriptional silencing and antisense RNA regulation, but retain functionality, as several genes were able to complement the orthologous deletions in a remotely related magnetotactic bacterium. The laboratory transfer of foreign magnetosome genes to R. atsumiense was found to endow the strain with magnetosome biosynthesis, but strong negative selection led to rapid loss of this trait upon subcultivation, highlighting the trait instability in this organism. Our results provide insight into the horizontal dissemination of gene clusters encoding complex prokaryotic organelles and illuminate the potential mechanisms of their genomic preservation in a dormant state.

A cream containing the sap of oat plantlets and mandarin extract soothes the symptoms of rosacea and improves the quality of life of patients.

BACKGROUND: Rosacea is a chronic inflammatory disease of the facial skin that affects all skin types and occurs mostly in adults. The main clinical sign of rosacea is a characteristic and persistent form of centro-facial erythema that is prone to exacerbation and can impair quality of life (QoL). The current therapeutic approach for rosacea is to combine various treatments, use appropriate skincare products and avoid flare-up triggers. OBJECTIVE: To evaluate the use of a facial skincare product containing protein-free sap extruded from Rhealba® oat plantlets and mandarin extract in subjects with rosacea. METHODS: Three clinical studies were conducted in adult subjects with various rosacea phenotypes (erythematotelangiectatic or papulopustular) and treatment histories to assess the dermatological and ophthalmological tolerance of the study product, as well as its clinical effectiveness, after a twice-daily application on the whole face and neck for up to 4 weeks. RESULTS: Tolerance of the product was rated as good to very good by dermatologists across the three studies, which involved a total of 105 evaluable subjects. Subjects with untreated erythematotelangiectatic rosacea reported fewer functional signs and symptoms of the disease and an improved QoL. The evaluation of skin biometric parameters revealed a reduction in transepidermal water loss, indicating that the study product helped to restore skin barrier integrity after 4 weeks, and a higher skin pH, indicating that the cutaneous microbiote was respected. Most subjects (93%) who had either undergone a superficial dermatological procedure for erythematotelangiectatic rosacea or were taking oral/topical treatments for papulopustular rosacea, rated the study product as very good (8/10) and felt it further relieved their symptoms. CONCLUSION: Overall, the study product was very well tolerated and may be beneficial for subjects with rosacea as an adjunct to superficial dermatological procedures or oral/topical therapies, in line with the current recommendations for rosacea management.

Toxicological impact of organic ultrafine particles (UFPs) in human bronchial epithelial BEAS-2B cells at air-liquid interface.

Air pollution has significant health effects worldwide, and airborne particles play a significant role in these effects. Ultrafine particles (UFPs) have an aerodynamic diameter of 0.1 µm or less, can penetrate deep into the respiratory tree, and are more toxic due to their large specific surface area, which should adsorb organic compounds. The aim of this study is to show the toxicological effects of UFPs with high organic content at low dose on BEAS-2B cells through at air-liquid interface (ALI) exposure using a Vitrocell® technology and a miniCAST (Combustion Aerosol Standard) generator. In conjunction with this approach, chemical analysis of particles and gas phase was performed to evaluate the presence of polycyclic aromatic hydrocarbons (PAHs). Chemical analyses confirmed the presence of PAHs in UFPs. With this experimental setup, exposure of the BEAS-2B cells induced neither cytotoxicity nor mitochondrial dysfunction. However, an increase of oxidative stress was observed, as assessed through Nrf2, NQO1, HO-1, CuZnSOD, MnSOD, and Catalase gene expression, together with significant induction of genes related to xenobiotic metabolism CYP1A1 and CYP1B1. Negative regulation of inflammatory genes expression (IL-6 and IL-8) was present three hours after the exposition to the UFPs. Taken together, this experimental approach, using repeatable conditions, should help to clarify the mechanisms by which organic UFPs induce toxicological effects.

Ice nucleation active bacteria in precipitation are genetically diverse and nucleate ice by employing different mechanisms.

A growing body of circumstantial evidence suggests that ice nucleation active (Ice+) bacteria contribute to the initiation of precipitation by heterologous freezing of super-cooled water in clouds. However, little is known about the concentration of Ice+ bacteria in precipitation, their genetic and phenotypic diversity, and their relationship to air mass trajectories and precipitation chemistry. In this study, 23 precipitation events were collected over 15 months in Virginia, USA. Air mass trajectories and water chemistry were determined and 33 134 isolates were screened for ice nucleation activity (INA) at -8 °C. Of 1144 isolates that tested positive during initial screening, 593 had confirmed INA at -8 °C in repeated tests. Concentrations of Ice+ strains in precipitation were found to range from 0 to 13 219 colony forming units per liter, with a mean of 384±147. Most Ice+ bacteria were identified as members of known and unknown Ice+ species in the Pseudomonadaceae, Enterobacteriaceae and Xanthomonadaceae families, which nucleate ice employing the well-characterized membrane-bound INA protein. Two Ice+ strains, however, were identified as Lysinibacillus, a Gram-positive genus not previously known to include Ice+ bacteria. INA of the Lysinibacillus strains is due to a nanometer-sized molecule that is heat resistant, lysozyme and proteinase resistant, and secreted. Ice+ bacteria and the INA mechanisms they employ are thus more diverse than expected. We discuss to what extent the concentration of culturable Ice+ bacteria in precipitation and the identification of a new heat-resistant biological INA mechanism support a role for Ice+ bacteria in the initiation of precipitation.

Impact of after-treatment devices and biofuels on diesel exhausts genotoxicity in A549 cells exposed at air-liquid interface.

Using an air-liquid interface (ALI) device in dynamic conditions, we evaluated the efficiency of fuel after-treatment strategies (diesel oxidation catalysis, DOC, and diesel particulate filter, DPF, devices) and the impact of 7% and 30% rapeseed methyl esters (RME) blending on oxidative stress and genotoxicity induced in A549 lung cells after 3h exposure to whole Diesel exhausts. Oxidative stress was studied using assays of ROS production, glutathione level, catalase and superoxide-dismutase (SOD) activities. No oxidative stress and no clear differences on cytotoxicity patterns between biodiesel and standard Diesel exhausts were found. A weak but significant genotoxicity (8-oxodGuo adducts) and, for standard Diesel only, a DNA damage response (DDR) as evidenced by ƔH2AX foci, remained after DOC+DPF flowing. All together, these data could contribute to the improvement of the after treatment strategies and to health risk assessment of current diesel exhausts.

A prospective, randomized, pharmacodynamic study of quick-starting a desogestrel progestin-only pill following ulipristal acetate for emergency contraception.

STUDY QUESTION: Is there a pharmacodynamic interaction between ulipristal acetate (UPA) 30 mg for emergency contraception and a daily progestin-only contraceptive pill, desogestrel (DSG) 0.75 mg, when initiated the next day? SUMMARY ANSWER: In this study, DSG impaired the ability of UPA to delay ovulation, but UPA had little impact on the onset of contraceptive effects due to DSG. WHAT IS KNOWN ALREADY: UPA is a progesterone receptor modulator used for emergency contraceptive (EC) at the dose of 30 mg. UPA delays ovulation by at least 5 days when administered in the mid to late follicular phase. In theory, potent progestins could reactivate progesterone signaling that leads to follicle rupture, thereby impacting the effectiveness of UPA as EC. In addition, UPA could alter the onset of the contraceptive effect of progestin-containing contraceptives started immediately after UPA. STUDY DESIGN, SIZE, DURATION: A single-blind (for observer), placebo-controlled, partial crossover study was conducted in two sites [Dominican Republic (DR) and the Netherlands (NDL)] over 11 months from October 2012 to September 2013. Healthy female volunteers participated in two of the three treatment cycles separated by a washout cycle. Treatment combinations studied were as follows: (i) a single 30 mg dose of UPA followed by 75 µg per day DSG for 20 days, (ii) a single 30 mg dose of UPA followed by 20 days of placebo matching that of DSG (PLB2) or (iii) one tablet of placebo-matching UPA (PLB1) followed by 75 µg per day DSG for 20 days. Participants were randomized to one of the three treatment sequences (UPA + DSG/UPA + PLB2, PLB1 + DSG/UPA + DSG and UPA + PLB2/PLB1 + DSG) when a lead follicle was ≥ 14 to <16 mm diameter on transvaginal ultrasound imaging (TVU). PARTICIPANTS/MATERIAL, SETTING, METHODS: A total of 71 women were included, and 49 were randomized to a first treatment combination of the three period sequences (20 in the DR and 29 in the NDL); 41 of the 49 continued and completed two treatment combinations (20 in the DR and 21 in the NDL). MAIN RESULTS AND THE ROLE OF CHANCE: Initiating DSG treatment the day after UPA significantly reduced the ovulation delaying effect of UPA (P = 0.0054). While ovulation occurred in only one of the 29 UPA-only cycles (3%) in the first 5 days, it occurred in 13 of the 29 (45%) UPA + DSG cycles. LIMITATIONS, REASONS FOR CAUTION: This was a small, descriptive, pharmacodynamic study in which some findings differed by study site. Distinguishing between a cystic corpus luteum and a luteinized unruptured follicle (LUF) by TVU was difficult in some cases; however, the investigators reached consensus, when the study was still blinded, regarding ovulation based on hormone levels and careful review of daily TVU images. WIDER IMPLICATIONS OF THE FINDINGS: Initiating the use of a DSG progestin-only pill (POP) immediately after UPA reduces the ability of UPA to delay ovulation and thus may decrease its efficacy as EC. If starting a DSG POP after using UPA for EC, and possibly any progestin-only method, consideration should be given to delaying for at least 5 days after UPA intake in order to preserve the ovulation delaying effects of UPA.

Evaluation of excreta management in a large French multi-hospital institution.

BACKGROUND: Excreta are a major source of multidrug-resistant Enterobacteriaceae including strains that produce extended-spectrum beta-lactamase (ESBL). The increase of ESBL incidence in Assistance Publique - Hôpitaux de Paris (AP-HP) hospitals prompted an evaluation of the equipment and practices used to dispose of excreta. AIM: To evaluate the use of equipment for the management of excreta and to review practices of healthcare workers in their disposal. METHODS: A cross-sectional survey was conducted in 2012. FINDINGS: A total of 28 AP-HP hospitals including 536 units (342 acute care units and 194 rehabilitation and long-term care units) were evaluated. Among the patients on the day of the survey, 5697 (43%) wore diapers and 1767 (13%) were using a bedpan. Sixty-one percent of the beds were equipped with shared toilets and 43% of the toilets were equipped with hand sprayers, a device favouring the spread of faecal material in the environment. Sixty eight percent of the units were equipped with bedpan washer-disinfectors. Only 52% of the bedpan washer-disinfectors were located in rooms where alcohol-based hand rubs (ABHRs) were available. In 71% of the units the bedpan was rinsed before disinfection, mostly in the patient's bathroom (62%). Finally, only 9% of questioned healthcare workers said they followed an educational programme about excreta disposal. CONCLUSION: This survey shows that, in the field of multidrug-resistant Enterobacteriaceae control and the promotion of hand hygiene with ABHRs, excreta management is a concerning but neglected subject.

Micromagnet arrays for on-chip focusing, switching, and separation of superparamagnetic beads and single cells.

Nonlinear magnetophoresis (NLM) is a novel approach for on-chip transport and separation of superparamagnetic (SPM) beads, based on a travelling magnetic field wave generated by the combination of a micromagnet array (MMA) and an applied rotating magnetic field. Here, we present two novel MMA designs that allow SPM beads to be focused, sorted, and separated on-chip. Converging MMAs were used to rapidly collect the SPM beads from a large region of the chip and focus them into synchronised lines. We characterise the collection efficiency of the devices and demonstrate that they can facilitate on-chip analysis of populations of SPM beads using a single-point optical detector. The diverging MMAs were used to control the transport of the beads and to separate them based on their size. The separation efficiency of these devices was determined by the orientation of the magnetisation of the micromagnets relative to the external magnetic field and the size of the beads and relative to that of micromagnets. By controlling these parameters and the rotation of the external magnetic field we demonstrated the controlled transport of SPM bead-labelled single MDA-MB-231 cells. The use of these novel MMAs promises to allow magnetically-labelled cells to be efficiently isolated and then manipulated on-chip for analysis with high-resolution chemical and physical techniques.

Subsarcolemmal and interfibrillar mitochondria display distinct superoxide production profiles.

Cardiac subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM) subpopulations display distinct biochemical, morphological, and functional characteristics. Moreover, they appear to be differently influenced during cardiac pathologies or toxic injuries. Although mitochondrial reactive oxygen species seem to play a critical role in cardiac function and diseases, limited information exists about the superoxide production characteristics of these mitochondrial subpopulations. In this work, using direct measurement of superoxide by electron paramagnetic resonance, we showed that differences in superoxide production profiles were present between cardiac IFM and SSM, in terms of intensity and major sites of superoxide generation. In SSM incubated with glutamate plus malate as substrates, the total observed superoxide levels were significantly higher than those observed with IFM, with an important contribution of the NADH-oxidizing site of complex I (site If) and the quinol-oxidizing site of complex III (site IIIQ0). In both IFM and SSM, succinate leads to similar rates of total superoxide levels with a substantial role for contribution of reverse electron transfer. Finally, using two spin probes with different membrane permeabilities, our data on complex III showed direct intra- and extra-mitochondrial superoxide release whereas complex I- and II-dependent superoxide were exclusively released inside the mitochondria, confirming previous studies. Feasibility of this approach to measure intra- and extra-mitochondrial superoxide levels and to characterize distinct superoxide production profiles of cardiac IFM and SSM has been demonstrated.

Long-term control of carbapenemase-producing Enterobacteriaceae at the scale of a large French multihospital institution: a nine-year experience, France, 2004 to 2012.

In 2009, following the occurrence of several outbreaks of carbapenemase-producing Enterobacteriaceae (CPE), a programme for controlling the spread of CPE was implemented in the 38 hospitals of the Assistance Publique-Hôpitaux de Paris, a 21,000-bed institution. This programme included recommendations to isolate, and screen for CPE, patients previously hospitalised abroad, and bundled measures to control cross transmission (barrier precautions, dedicated staff and screening of contact patients). From 2004 to 2012, 140 CPE index cases were identified, 17 leading to outbreaks. After application of the programme, in spite of an increase in the number of CPE index cases epidemiologically linked with a recent stay or hospitalisation abroad, the proportion of cases followed by outbreaks, which was 40% (4/10) before 2009, decreased to 10% (13/130) (p=0.02), and the proportion of secondary cases among all CPE cases decreased from 69% (22/32) to 23% (38/168), (p<0.001). The number of secondary cases varied significantly depending on the speed and strength of the measures implemented around the CPE index case: quick (within two days of patient admission at the hospital) setting of nursing staff dedicated to the patient, quick setting of simple barrier precautions, or delayed measures of control (p=0.001). A sustained and coordinated strategy can lead to control CPE at the level of a large regional multi-hospital institution in a country where CPE are at an emerging stage.

Immunosuppressant regimen based on sirolimus decreases aortic stiffness in renal transplant recipients in comparison to cyclosporine.

Whether or not a cyclosporine A (CsA)-free immunosuppressant regimen based on sirolimus (SRL) prevents aortic stiffening and improves central hemodynamics in renal recipients remains unknown. Forty-four patients (48 ± 2 years) enrolled in the CONCEPT trial were randomized at week 12 (W12) to continue CsA or switch to SRL, both associated with mycophenolate mofetil. Carotid systolic blood pressure (cSBP), pulse pressure (cPP), central pressure wave reflection (augmentation index, AIx) and carotid-to-femoral pulse-wave velocity (PWV: aortic stiffness) were blindly assessed at W12, W26 and W52 together with plasma endothelin-1 (ET-1), thiobarbituric acid-reactive substances (TBARS) and superoxide dismutase (SOD) and catalase erythrocyte activities. At W12, there was no difference between groups. At follow-up, PWV, cSBP, cPP and AIx were lower in the SRL group. The difference in PWV remained significant after adjustment for blood pressure and eGFR. In parallel, ET-1 decreased in the SRL group, while TBARS, SOD and catalase erythrocyte activities increased in both groups but to a lesser extent in the SRL group. Our results demonstrate that a CsA-free regimen based on SRL reduces aortic stiffness, plasma endothelin-1 and oxidative stress in renal recipients suggesting a protective effect on the arterial wall that may be translated into cardiovascular risk reduction.

Rapid Aeromonas hydrophila identification by TaqMan PCR assay: comparison with a phenotypic method.

AIMS: Aeromonas hydrophila is recognized as a human pathogen following wound exposure or ingestion of contaminated water and food. For rapid identification of this bacterium, a TaqMan-based real-time PCR assay has been developed. METHODS AND RESULTS: Primers and probes that target specific sequences of the 16S rRNA gene and cytolytic enterotoxin gene (aerA) were combined in a duplex assay. Presence and size of PCR products were confirmed with microchannel fluidics electrophoresis analysis. After validation, using type strain CIP7614T DNA, the PCR assay was tested on 12 positive and negative controls. Twenty-one Aeromonas strains were isolated from environmental samples and were identified with biochemical tests as Aer. sobria, Aer. caviae and Aer. hydrophila. Only Aer. hydrophila strains tested positive by PCR assay. CONCLUSIONS: The PCR developed here was successfully applied for the identification of Aer. hydrophila from reference, clinical and environmental samples and showed a high discrimination between Aer. hydrophila and other Aeromonas species. SIGNIFICANCE AND IMPACT OF THE STUDY: This molecular method is convenient, rapid (2.5 h vs 24 h), specific to identify Aer. hydrophila and usable for diagnosis in medical and veterinary laboratories.

[An example of simulation for a better understanding of PK/PD relationship of antibiotics]. / Un exemple de modélisation permettant une meilleure compréhension de la relation PK/PD des antibiotiques.

The interpretation of PK/PD indices is specific to each class of antibiotics. In order to illustrate this, we developed a multidisciplinary tutorial program based on simulation of clinical cases. Three drugs were included in this software: tobramycin, vancomycin and azithromycin. From the dosage regimen proposed by the user, the model simulates a plotting of antibiotic plasma concentrations vs. time (tobramycin, vancomycin and azithromycin) and tissue concentrations (azithromycin). Peak and trough concentrations are calculated at steady-state. A commentary is provided to evaluate the efficacy of treatment and to assist the user in improving his prescription of tobramycin or vancomycin. T(> MIC) (time the concentration remains above the MIC) and AUC(24) (area under the concentration-time curve) are calculated in plasma and tissues for azithromycin. In order to create a link between theoretical pharmacokinetics and clinical practice, we propose this model as a simulation of antibiotic monitoring. We put the emphasis on interactivity and simulation, leading to applied reasoning and decision making. It illustrates (i) the influence of pharmacokinetic parameters, location of infection and bactericidal kinetics on the use of three different classes of antibiotics, (ii) the role of route of administration, dosing and intervals between administrations on therapeutic response and (iii) the influence of erratic administrations on clinical efficacy.

[Virulence factors of clinical Aeromonas caviae isolates]. / Facteurs de virulence d'Aeromonas caviae isolés de cas cliniques.

Aeromonas caviae, an ubiquitous aquatic organism, has long been considered to be of low pathogenicity, and its virulence mechanisms are still not clearly understood. Twenty-eight A. caviae isolates of clinical origin, most often monomicrobic, were identified in our university hospital over a four year period. Patients, mostly immunocompromised, were: eight diarrhoeal infants, 13 diarrhoeal adults, seven bacteraemic adults. Adults were frequently suffering from underlying intestinal malignancy, hepatobiliary disease, gastrectomy. Virulence factors were investigated. Adherence, studied by use of tissue culture HEp-2 cells, and staining of characteristic lateral flagella, were observed in diarrhoeal strains. Extracellular hemolytic activity was tested on rabbit erythrocytes suspensions at 25 and 37 degrees C. One blood culture isolate showed an important hemolytic activity at 25 degrees C, but none at 37 degrees C. Treatment with furin activated the aerolysin precursor and resulted in significant hemolysis at 37 degrees C, and fluid accumulation in rabbit ileal loops similar to that of A. hydrophila as control. The presence of the hemolysin gene was confirmed in this strain by PCR. In conclusion, A. caviae was shown to be a pathogen isolated from diarrhoea and bacteraemia in immunocompromised patients with malignancies and low gastric acidity as favouring factors. Virulence including the ability to adhere to cells and the production of lateral flagella was observed in diarrhoeal strains. The expression and the production of extracellular hemolytic activity and enterotoxicity at 37 degrees C depended on the activation of the pore forming toxin aerolysin precursor by furin. In vivo the protoxin is probably processed to its mature form by host proteases.

[Evaluation of an information document about patients and transfusion]. / Evaluation du document d'information des patients sur la transfusion.

OBJECTIVE: To evaluate the understanding of written information contained in the information sheet for patients intended to receive an homologous transfusion and to know their opinion about this document. TYPE OF THE STUDY: A prospective cohort survey carried out by people unrelated to clinical units and transfusion services. METHODS: A document divided in two parts, the first one summarized, the second detailed, was distributed to transfused adult patients. The patients were hospitalized in the general surgery and orthopedic wards of two hospitals and in the hematology and oncology wards of two different hospitals. A questionnaire was filled out in the presence of the inquirer. RESULTS: Sixty one subjects have been enrolled, among them 53 considered the information as adequate; 53 as comforting and neutral. 53 patients considered a written information as essential and 52 estimated that both part of the information sheet (summarized and detailed) were mandatory. Conversely, a more in depth investigation revealed there was a gap between patients statements and their true understanding. CONCLUSION: The value of a written information for the patients is confirmed by the study. In addition, patients were not generally worried by this information. The partition of the document has been appreciated. It is noteworthy that a gap exist between the patient's perception of the information and their actual level of understanding.

Development of a new in vitro system for continuous in vitro exposure of lung tissue to complex atmospheres: application to diesel exhaust toxicology.

The purpose of this study was the development of a new incubation system that can allow continuous exposure of lung tissue to complex atmospheres as a tool for the assessment of aerial environmental lung toxicology. To assess the pertinence of this new exposure system, we studied the impact of diesel engine exhausts as a complex atmosphere containing both gaseous and particulate fractions and have been able to discriminate between the toxicological impacts of the gaseous phase and particulate matter from diesel exhausts. Continuous flow-through rotating chambers with controlled PO2, pCO2, and hygrometry have been designed in which lung slices are positioned in rolling inserts that allow free access of atmosphere to the exposed lung tissue. Under control conditions, cell viability was preserved for at least 48 h as assessed by intracellular ATP, GSH, and K+ levels and slice O2 consumption levels. Short-term exposure (1 h) to diesel whole exhausts did not affect intracellular potassium or slice O2 consumption, while intracellular ATP and GSH levels were markedly decreased. Exposure to filtered exhausts showed less marked effects on both ATP and GSH levels. Superoxide dismutase activity was decreased in a similar way by both total and filtered exhausts while Se(+)-dependent glutathione peroxidase activity was induced by filtered exhausts to a larger extent than after total exhaust exposure, showing different response patterns of lung tissue after exposure to whole or filtered exhausts. In conclusion, this newly designed model opens a promising area in in vitro environmental lung toxicology testing.

Predominant Staphylococcus aureus isolated from antibiotic-associated diarrhea is clinically relevant and produces enterotoxin A and the bicomponent toxin LukE-lukD.

Staphylococcus aureus was isolated as the predominant or only isolate from cultures of stools of 60 patients over 2 years in a university hospital, leading to the collection of 114 isolates. Diarrhea was observed in 90% of the patients. Ninety-eight percent of the patients had received antibiotics in the month before the diarrhea. Ninety-two percent of the S. aureus isolates were methicillin resistant. S. aureus was encountered with antibiotic-associated diarrhea among 47 quite elderly patients affected or not affected by a gastrointestinal disease. Among the antimicrobial treatments, cessation of the previous therapy when possible or rapid application of oral vancomycin therapy was the most appropriate. Analysis of total DNA by pulsed-field gel electrophoresis revealed 27 different SmaI pulsotypes distributed in 15 clusters. The pulsotypes never differed for related isolates from a single patient, even if they originated from patients with bacteremia. S. aureus was not isolated as the predominant isolate in cultures of stools of 57 patients who received an antimicrobial treatment for more than 5 days without diarrhea. Occurence of production of both enterotoxin A and the bicomponent leucotoxin LukE-LukD by the S. aureus isolates was significantly different from that by random isolates. The results strongly suggest that when predominant in stool samples, S. aureus should be considered a possible etiologic agent for some cases of antibiotic-associated diarrhea.

Acrolein toxicity: comparative in vitro study with lung slices and pneumocytes type II cell line from rats.

Toxicological effects of acrolein have been studied in precision-cut rat lung slices and in L2 cells, a rat pneumocyte II cell line. These two models were cultured for 24 h with or without acrolein (0-100 microM in L2 cells; 0-200 microM in lung slices). Treatment with this pneumotoxicant produced a concentration dependent decrease in intracellular ATP levels. Acrolein concentrations higher than 50 microM induced ATP decrease in slices, while this decrease occurred from 10 microM acrolein in L2 cells. Detoxification marker evaluations showed that mostly the glutathione pathway was altered after acrolein treatment in both models. Intracellular glutathione (GSH) levels were drastically increased with an acrolein concentration of 10 microM. This increase was concomitant with glutathione-S-transferase (GST) and glutathione reductase (GRED) activities in L2 cells. After this strong increase, these enzymatic activities as well as GSH levels were quickly decreased. In precision-cut rat lung slices, the induction of the glutathione pathway was less clear-cut. A bell-shaped dose response curve was observed with a maximum for 5 microM acrolein for GST and GRED activities. These differences between acrolein toxic ranges could be explained by the presence of an active detoxification pathway in slices compared to its relative lack in L2 cells.