Comparative genomics, proteomics and transcriptomics give new insight into the exoproteome of the basidiomycete Hebeloma cylindrosporum and its involvement in ectomycorrhizal symbiosis

Extracellular proteins play crucial roles in the interaction between mycorrhizal fungi and their environment. Computational prediction and experimental detection allowed identification of 869 proteins constituting the exoproteome of Hebeloma cylindrosporum. Small secreted proteins (SSPs) and carbohydrate-active enzymes (CAZymes) were the two major classes of extracellular proteins. Twenty-eight per cent of the SSPs were secreted by free-living mycelia and five of the 10 most abundant extracellular proteins were SSPs. By contrast, 63-75% of enzymes involved in nutrient acquisition were secreted. A total of 150 extracellular protein-coding genes were differentially expressed between mycorrhizas and free-living mycelia. SSPs were the most affected. External environmental conditions also affected expression of 199 exoproteome genes in mycorrhizas. SSPs displayed different patterns of regulation in response to presence of a host plant or other environmental signals. Several of the genes most overexpressed in the presence of organic matter encoded oxidoreductases. Hebeloma cylindrosporum has not fully lost its ancestral saprotrophic capacities but rather adapted them not to harm its hosts and to use soil organic nitrogen. The complex and divergent patterns of regulation of SSPs in response to a symbiotic partner and/or organic matter suggest various roles in the biology of mycorrhizal fungi.

Risk factors for Pseudomonas aeruginosa acquisition in intensive care units: a prospective multicentre study

BACKGROUND

Pseudomonas aeruginosa is a major nosocomial pathogen in intensive care units (ICUs); however, endogenous versus exogenous origin of contamination remains unclear.

AIM

To identify individual and environmental ICU risk factors for P. aeruginosa acquisition.

METHODS

A five-month prospective multicentric study was performed in ten French ICUs. Adult patients hospitalized in ICU for ≥ 24 h were included and screened for P. aeruginosa colonization on admission, weekly and before discharge. P. aeruginosa acquisition was defined by a subsequent colonization or infection if screening swabs on admission were negative. Water samples were obtained weekly on water taps of the ICUs. Data on patient characteristics, invasive devices exposure, antimicrobial therapy, P. aeruginosa water and patient colonization pressures, and ICU characteristics were collected. Hazard ratios (HRs) were estimated using multivariate Cox model.

FINDINGS

Among the 1314 patients without P. aeruginosa on admission, 201 (15%) acquired P. aeruginosa during their ICU stay. Individual characteristics significantly associated with P. aeruginosa acquisition were history of previous P. aeruginosa infection or colonization, cumulative duration of mechanical ventilation and cumulative days of antibiotics not active against P. aeruginosa. Environmental risk factors for P. aeruginosa acquisition were cumulative daily ward 'nine equivalents of nursing manpower use score' (NEMS) [hazard ratio (HR): 1.47 for ≥ 30 points; 95% confidence interval (CI): 1.06-2.03] and contaminated tap water in patient's room (HR: 1.76; CI: 1.09-2.84).

CONCLUSION

Individual risk factors and environmental factors for which intervention is possible were identified for P. aeruginosa acquisition.

Identification and prioritization of bioaccumulable pharmaceutical substances discharged in hospital effluents

The consumption of pharmaceuticals and their excretion in wastewater is a continuous source of pollution for aquatic ecosystems. In certain cases these compounds are found in the environment at concentrations high enough to cause disturbance in aquatic organisms. Aware of this problem hospitals are giving increasing attention to the nature of their effluents and their impact on the environment, by implementing more efficient effluent management policies. This concern is justified in view of the large volumes of toxic products consumed (detergents, disinfectants, pharmaceuticals, chemical reagents, radioactive elements, etc.). Moreover, these effluents usually do not undergo any specific treatment before being discharged into urban sewage networks. In this article, we present a method for selecting the pharmaceuticals discharged in hospital effluents that have the worst impact on the aquatic ecosystem, primarily based on their bioaccumulation potential. This study focused on the pharmaceuticals consumed at the Hospices Civils de Lyon (HCL), the second largest hospital structure in France (5200 hospital beds). Of the 960 substances consumed in HCL hospitals, a shortlist of 70 substances considered as being potentially bioaccumulable was established. The use of aggravating factors of risk has then led to the final selection of 14 priority compounds. They include 4 compounds consumed in large quantities in HCL hospitals, 6 endocrine disruptors and 4 potentially ecotoxic compounds. For all these compounds, it is now advisable to verify their bioaccumulation potential experimentally and confirm their presence in the environment. In addition, in order to monitor the risk relating to possible contamination of the food chain, it will be necessary to measure accumulated dose levels in species of different trophic levels. Lastly, chronic ecotoxicity tests will permit evaluating the danger and risk that some of these substances may represent for aquatic ecosystems.

Daily physicochemical, microbiological and ecotoxicological fluctuations of a hospital effluent according to technical and care activities

The problem of hospital effluents falls into the framework of hazardous substances due to the specific substances used and discharged for the most part into urban drainage networks without prior treatment. This in-depth study has led to greater understanding of the effluents discharged by hospitals. The experimental program implemented consisted in carrying out parallel sampling of the effluents of one hospital: a 24 h-average sample and 5 periodic samples corresponding to fractions of times and hospital activities. The samples were characterized by physicochemical, microbiological and ecotoxicological analyses. The results highlight that the effluents contained very little bacterial flora and a moderate organic pollution. However, a numerous of specific pollutants were detected: AOX, glutaraldehyde, free chlorine, detergents, Freon 113 as well as alcohols, acetone, formaldehyde, acetaldehyde, ammonium, phenols and several metals. The battery of bioassays showed that the effluents had a high level of ecotoxicity partly linked to particles in suspension and, that pollution fluctuated greatly during the day in connection with hospital activities. Finally, the PNEC values compared to the concentrations of pollutants dosed in the effluents highlighted that their toxicity was mainly due to several major pollutants, in particular free chlorine. Some hypotheses require additional experiments to be carried out. They concern: reactions of fermentations likely to occur in the drainage network and to form secondary toxic compounds, retention of chlorine by particles and physicochemical characterization of suspended solids.

A rapid and easy PCR-RFLP method for genotyping Serratia marcescens strains isolated in different hospital outbreaks and patient environments in the Lyon area, France

A new genotyping method for Serratia marcescens is described. This method uses the flagellin gene as target for polymerase chain reaction amplification and Alu I restriction fragment length polymorphism. The strains tested belonged to 13 different hospital clusters of S. marcescens isolated between 1983 and 1988, concerning outbreaks and/or patient environments in different hospital units in Lyon and the Rhone-Alpes region of France. Initially, the classification had been performed by marcescinotyping. These strains were then tested by ribotyping and genotyping of the flagellin gene. Genotyping showed similar classification to ribotyping. The genotyping method is the easiest technique, as reproducible as ribotyping, and with almost the same ability to discriminate different strains. It does not need expensive equipment, is more rapid, and is less labor intensive than ribotyping. With this method, all strains of S. marcescens including sporadic isolates could be amplified and typed. Antibiotic sensitivity determination was found to be a useful complementary and confirmation test for all these typing methods.

A new concept of plaster for preventing hand-borne infections

A new plaster has been developed to improve asepsis in current medical and nursing care. Technical improvements were achieved via a no touch' technique. The experimental protocol used to evaluate this new plaster allows us to claim its evident superiority because of the no touch' principle and rapid application. Such a plaster appears to be very helpful in diminishing the incidence of hand-borne infections during medical and nursing care.

Quantitative determination of endotoxins released by bacterial biofilms

Residual endotoxins, commonly associated with bacterial biofilms colonizing reusable medical devices have been associated with pyrogenic reactions in patients. We have used a quantitative, sensitive and reproducible kinetic chromogenic adaptation of the Limulus Amebocyte Lysate assay to assess endotoxin recovery from an in-vitro bacterial biofilm. The 'recovery method' was based on a combination of physical treatment (vortexing and sonication) and chemical treatment (immersion in recovery solution). Five recovery solutions were investigated. The recovered endotoxin was greater when the biofilm was treated with a 1% SDS solution. The sensitive and reproducible method we have developed should allow the recovery and measurement of biofilm bacterial endotoxins on implanted and colonized medical devices. Moreover, the amount of endotoxin was sufficient (> 1000 endotoxin units/cm2 of substrate) to enable a substantial reduction by sterilization processes, the efficiency of which on biofilm endotoxins has yet to be proven.

[Osteosynthesis of the spine using Cotrel-Dubousset instrumentation. Contribution of x-ray computed tomography with 3D reconstruction]

3D reconstruction is of a great interest in the study of the osteosynthesis of the spine by C-D material, where MRI is impossible and CT usually artifacted. The results obtained by 3D reconstruction allow visualization of osseous, extra osseous (disks, ligaments...) and metallic structures.

[Cross-forearm replantation in bilateral amputation]

We report the case of a 27-year-old patient who sustained a traumatic amputation of his 4 limbs. For the right upper limb, the site of amputation was at the level of the upper third of the forearm. For the left upper limb, the site of amputation was at the level of the Cower third of the forearm. In both cases, the loss of soft tissue was so extensive that hand replantation was impossible in the initial position. In such an unusual case, replantation of the right hand to the left side was attempted in this young patient. Osteosynthesis of the radius to the ulna in supination was performed, and arteries, veins, nerves and tendons were repaired. The other segments of amputated limbs were debrided and cleaned. Within a year, protective sensibility was restored in the replanted hand, but intrinsic muscles were paralysed. Secondarily, transfer of thumb opposition and capsulorrhaphy at the level of the metacarpophalangeal joints of long fingers were performed in order to provide a useful key-grip between the three first fingers.

Invasive nosocomial pulmonary aspergillosis: risk factors and hospital building works

A retrospective epidemiological study of 22 observations of invasive pulmonary aspergillosis, of which 18 were fatal, occurring over a period of 30 months, implicated certain building sites within the hospital. The building works were responsible for the diffusion into the atmosphere of fungal spores from normally closed reservoirs, notably false ceilings, fibrous thermal and/or acoustic insulation materials and roller-blind casings. The results of our study permit us to suggest that protective measures should be set up or that immunodepressed patients are evacuated when such works are to be carried out in an in-patient establishment.

[Intranuclear structures of monkey kidney cells recognised by immunofluorescence and immuno-electron microscopy using anti-ribonucleoprotein antibodies (author's transl)]

Autoantibodies which react with a ribonucleoprotein material present in the saline extract of nuclei have been found in the sera of patients with Sharp's syndrome and in some cases of systemic lupus erythematosus and of systemic sclerosis. Such antibodies give a granular or reticulated immunofluorescence staining of the nuclei of mouse peripheral blood leukocytes. When cultures of monkey kidney cells (Macacus cynomolgus) were examined by immunofluorescence using such antibodies, it was found that the staining pattern depended on the state of the cell cultures. Nuclei of cells in stationary cultures showed the presence of perinucleolar granules of RNP whereas, within a few hours after subculture, the nuclei contained widely dispersed specks of antigen. In mitotic cells the antigen appears to be evenly dispersed throughout the cell volume with the exception of the chromosomes. Immuno-electron microscopy of cells treated 24 hours after subculture indicates that the specks correspond to aggregates of 200--250 A granules, probably interchromatin granules.

[Absence of anti double stranded DNA antibodies in viral hepatitis (author's transl)]

The presence of anti double stranded DNA antibodies (ds DNA Ab) in the sera of patients with acute viral hepatitis and B virus chronic active hepatitis has recently been described. In contrast with these results we found no ds DNA ab, but anti single stranded DNA antibodies (ss DNA ab) in the sera from patients with these diseases. The ds DNA ab were studied simultaneously by two methods: Immunofluorescence (IF) on crithidia luciliae and Farr test. In this later case it was shown that the ds DNA preparation contained no ss DNA because it did not react with an anti ss DNA rabbit serum. Our results indicate that the above mentioned authors have been using in their Farr test a preparation of ds DNA contaminated by ss DNA, thus revealing the presence of anti ss DNA ab but not anti ds DNA ab, in the sera of their patients. On the other hand the presence of ds DNA ab has been shown in the sera of 85% of the patients with systemic lupus erythematosus and of 20,5% of the patients with non EB chronic active hepatitis. At least one part of these later are probably autoimmune diseases.