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Objectives The study objectives were to describe the investigation and management of an imipenem-resistant Acinetobacter baumannii outbreak that occurred in the 15-bed ICU of a tertiary care teaching hospital (Brest, France), during the summer 2008. Patients and methods Patients harboring an imipenem-resistant A. baumannii strain were defined as case patients. We described case occurrence and steps taken to control the outbreak: contact isolation, reinforcement of hygiene procedures, unit shutdown decision, unit disinfection, and reopening. We also made a case control study and a cost analysis of the outbreak management. Results During a 10-day period, five patients were positive for a single clone of imipenem-resistant oxa-23 A. baumannii. Four patients presented with ventilation-acquired pneumonia and one was asymptomatic. The first two patients died one day after the first swab which led to the identification of A. baumannii. No additional case was noted in the ICU or in other hospital units after deciding to close the ICU. The cost of outbreak management was estimated at 264,553 euros. The case control study identified several factors associated with infection or colonization: length of stay in the ICU, chronic respiratory disease, number of previous antibiotic classes used, duration of ventilation, prone position, echocardiography, and presence of a nasogastric tube. Conclusion This outbreak occurred during the summer period requiring the shutdown of the ICU and inducing a considerable cost. Rapid reactions of the ICU staff during the outbreak enabled to limit the epidemic.

Resume Cette etude menee entre 1997 et 2003 en Bretagne sur les pneumocoques responsables d'infections invasives, evalue la sensibilite aux antibiotiques et les serogroupes des souches isolees de bacteriemies, de meningites et d'otites chez les enfants et les adultes. En 2003, 62 % des souches sont de sensibilite diminuee a la penicilline, 11 % sont resistantes. La prevalence des souches resistantes a l'erythromycine atteint 63 %. Ces taux de resistances sont les plus importants dans la population infantile. Les serogroupes 14 et 19 sont les plus frequents, surtout parmi les enfants. L'emergence notable du serogroupe 19 pourrait etre due a l'utilisation du vaccin conjugue heptavalent introduit en France en 2001. La surveillance des pneumocoques reste necessaire pour detecter les serogroupes emergents et les resistances.

Resume Treize laboratoires bretons ont collecte 832 souches de Streptococcus pneumoniae en 1999 chez 312 (37,5 %) femmes et 518 (62,2 %) hommes hospitalises ou consultants. Cette population comprenait 255 (30,6 %) enfants. Cent quatre-vingt-huit (22,6 %) souches ont ete isolees d’hemocultures, 16 (1,9 %) de LCR, 449 (54 %) de prelevements pulmonaires qu’ils soient proteges (8,1 %) ou non (45,9 %) et 88 (10,6 %) de pus d’otite moyenne aigue. La diminution de la sensibilite a la penicilline G (PSDP) a ete mesuree par un disque d’oxacilline 5 μg selon les recommandations du CA-SFM. Les CMI de la penicilline G, de l’amoxicilline et du cefotaxime ont ete mesurees sur une partie des PSDP par la methode de dilution en gelose. Soixante-cinq pour-cent (546/832) des pneumocoques sont des PSDP, 33,5 % des PSDP sont resistants a la penicilline G, 2,2 % sont resistants a l’amoxicilline et 0,2 % au cefotaxime. L’activite de l’erythromycine, de la tetracycline et du cotrimoxazole, determinee par diffusion en gelose, confirme l’association de la resistance a ces antibiotiques aux PSDP. Le serotypage des PSDP retrouve les types predominants 23 (23,7 %), 14 (23,5 %) et souligne l’augmentation de frequence du type 19 (19,1 %). Dans notre region, l’augmentation constante des PSDP (1993–1994 : 28,5 % ; 1997 : 56,4 % ; 1999 : 65,6 %) pourrait peut-etre etre expliquee par l’analyse des donnees sociologiques et demographiques specifiques.

The Sn/Ge(111) interface has been investigated across the 3 x 3 -->, root 3 x root 3 R30 degrees phase transition using core level and valence band photoemission spectroscopies. We find, both above and below the transition, two different components in the Sn 4d core level and a bond splitting in the surface state crossing the Fermi energy. Theoretical calculations show that these two effects are due to the existence of two structurally different kinds of Sn atoms that fluctuate at room temperature between two positions and are stabilized in a 3 x 3 structure at low temperature.

The Ge(111)-I surface has been studied at different I coverages ranging from 0.05 ML up to saturation, and different annealing temperatures, using photoelectron spectroscopy (PES) and scanning tunneling microscopy (STM). At saturation the surface is covered with I in the top site and GeI2 species in the bridge site, coexisting with small islands/clusters comprising GeI2, giving a total coverage of I in GeIx species of 1.15 ML. The chemically induced shifts in the Ge 3d core level are 0.39 eV per attached I atom. The coverage determined from the I 4d core level is higher than 1.15 ML, which we explain by the presence of I not bound to Ge. Annealing at 200°C decreases the iodine coverage, whereas the I 4d and Ge 3d line profiles are practically unchanged. Further heating desorbs the iodide species and restores the virgin c(2 × 8) structure.

Angle-resolved ultraviolet photoelectron spectroscopy has been used to study the electronic structure of a Si(110)2×3-Sb surface. The surface shows a semiconducting behavior with the highest occupied surface-state band observed around 1.8 eV below the Fermi level (EF). A second state is observed at Γ at 2.2 eV below EF dispersing >2.0 eV towards higher binding energies along the [110] and [111] directions. A third state is observed along the [111] direction around the M point. Surface differential reflectivity experiments showed no optical transitions up to an energy of 3.5 eV, indicating that the minimum energy position of the lowest empty band must be at least 1.8 eV above EF.

We use low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) to study the In-terminated InAs(001) surface prepared by argon sputtering and annealing. Characterization by LEED shows the formation of a highly ordered surface with a mixture of (4\ifmmode\times\else\texttimes\fi{}2) and $c(8\ifmmode\times\else\texttimes\fi{}2)$ phases. We systematically vary the sample bias in STM to obtain bias-dependent images over the same surface regions, allowing discrimination between topographic and electronic features. Atomic resolution STM images confirm the existence of both (4\ifmmode\times\else\texttimes\fi{}2) and $c(8\ifmmode\times\else\texttimes\fi{}2)$ phases and identify an electronic signature at the transition between the two reconstructions. Images of (4\ifmmode\times\else\texttimes\fi{}2) regions are consistent with a previously proposed model for this surface in which the unit cell contains one In dimer in the first layer and two In dimers in the third layer. The $c(8\ifmmode\times\else\texttimes\fi{}2)$ reconstruction, though similar to the (4\ifmmode\times\else\texttimes\fi{}2), is found to arise from a shift in the third- and/or first-layer In dimers by one lattice spacing. Filled-state imaging at the (4\ifmmode\times\else\texttimes\fi{}2)-to-$c(8\ifmmode\times\else\texttimes\fi{}2)$ boundary shows two bright spots positioned midway between the first-layer In dimer rows. In empty states, these spots are entirely absent, underlining their electronic origin. These electronic features are explained in terms of a localization of charge due either to a structural defect or to the presence of a sulfur doping atom at the transition from (4\ifmmode\times\else\texttimes\fi{}2) to $c(8\ifmmode\times\else\texttimes\fi{}2)$ reconstructions.

Go-adsorption of tin and potassium is found to induce a 3x1 reconstruction on the Ge(lll) surface. A very small amount of tin influences the Ge 3d core level spectra substantially compared to the G ...

The electronic properties of clean Si(110)16 × 2 and Si(110)2 × 3-Sb surfaces have been studied by angle resolved ultraviolet photoelectron spectroscopy (ARUPS) and surface differential reflectivity (SDR). For the clean 16 × 2 surface four surface states have been recognized by ARUPS and their dispersions have been mapped along the main symmetry lines in the surface Brillouin zone. SDR experiments revealed transitions between filled and empty surface states at ∼ 1.8, 2.4 and 2.9 eV. Antimony has been subsequently evaporated (about one monolayer) thus obtaining a 2 × 3 reconstruction. The surface electronic structure resulted to be strongly modified with three surface state bands observed in ARUPS along the [ 1 11] direction and no optical transitions detected by SDR in our energy range (1.3–3.5 eV).

The electronic properties of clean Si(110)16x2 and Si(110)2x3Sb surfaces have been studied by Angle Resolved Ultraviolet Photoelectron Spectroscopy (ARUPS) and Surface Differential Reflectivity (SDR). For the clean 16×2 surface four surface states have been recognized by ARUPS and their dispersions have been mapped along the main symmetry lines in the surface Brillouin zone. SDR experiments revealed transitions between filled and empty surface states at ∼1.8, 2.4 and 2.9 eV. Antimony has been subsequently evaporated (about one monolayer) thus obtaining a 2×3 reconstruction. The surface electronic structure resulted to be strongly modified with only two surface state bands observed in ARUPS and no optical transitions detected by SDR in our energy range (1.3–3.5 eV).

High-resolution core-level photoelectron spectroscopy has been used to study three different silver induced surface reconstructions on the Ge(111) surface. At the lowest coverage a (4 X 4) structur ...

A structure model for the Ge(111)-Au(\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{} surface reconstruction is proposed based on scanning tunneling microscopy (STM) and photoelectron spectroscopy on the Ge 3d and Au 4f core lines. The basic unit is a ${\mathrm{Au}}_{3}$Ge molecule binding in one-third of the ${\mathit{T}}_{1}$ substrate sites with a gold trimer pointing out of the surface. This leaves two-thirds of a monolayer of unoccupied ${\mathit{T}}_{1}$ sites which make up a hexagonal honeycomb pattern. Two types of STM images have been obtained which are explained within this model, where either the trimers or the substrate Ge atoms are probed depending on the specific tip conditions in combination with the sample bias voltage. Furthermore, small insets of a metallic (1\ifmmode\times\else\texttimes\fi{}1) structure are found at low gold coverage together with a distorted (2\ifmmode\times\else\texttimes\fi{}2) surface structure.

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The growth and optical properties of a two-dimensional metal were studied by spectroscopic ellipsometry. As a model system, non-intermixing Pb Ge(111) was chosen. The optical properties of the adlayer were determined in the visible spectral range. A semiconductor-metal transition of the surface is identified below monolayer coverage. It is shown to be a function of the energy of the exciting photons.

At this time, many antibiotics have decreased activity against Streptococcus pneumoniae, a major agent of infectious disease. In this study, we evaluated antibiotic susceptibility and serogroups of strains isolated from bacteraemia, meningitis and acute otitis media in adults and children over the 1997-2003 period in Brittany, France. In 2003, 62% of the isolates were not susceptible to penicillin and 11% were fully resistant. The prevalence of erythromycin resistance was 63%. Resistance rates were higher among isolates recovered from children than adults. Serogroups 19 and 14 were the most frequently isolated, especially the 19 one among children. The emergence of this serogroup might be a consequence of the use of heptavalent conjugate vaccine introduced in 2001 in France. Future surveillance after vaccination will be needed to detect emerging serogroups and resistance among S. pneumoniae.

Throughout 1999, clinical microbiology laboratories of 13 hospitals in Brittany have recovered Streptococcus pneumoniae isolates in 832 patients, 312 (37.5%) female and 518 (62.2%) male. Two hundred fifty five of them (30.6%) were children. One hundred eighty eight isolates were recovered from blood cultures (22.6%), 16 from CSF (1.9%), 449 from lungs (54%), and 88 from ear exsudates (10.6%).A 5 microgram oxacillin-disk test was used to detect isolates with reduced susceptibility to penicillin G. Determination of MICs of penicillin G, amoxicillin and cefotaxime were then performed by agar dilution method on 402 strains previously categorized resistant or intermediate. Five hundred forty six isolates were PSDP, 33.5% of them were resistant to penicillin G, 2.2% to amoxicillin and 0.2% to cefotaxime. As expected, a decreased susceptibility to beta-lactamins was frequently associated with resistance to macrolides, cotrimoxazole and tetracycline. Among PSDP, the most prevalent serotypes were 23 (23.7%), 14 (23.5%) and 19 (19.1%). In Brittany, the constant rise of PSDP (1993-1994: 28.5%; 1997: 56.4%; 1999: 65.6 %) could be perhaps explain by analysis of social and demographic data.

We have studied by ellipsometry the surface optical response of clean reconstructed Ge(111) between room temperature and a value very close to the melting point. By scanning the temperature at constant wavelength we detected three reversible surface phase transitions. The first is the well known c(2 × 8)−(1 × 1) transition around 250°C. A second one occurs between 700 and 750°C and is probably related to the order-disorder transition reported by McRae (Phys Rev Lett, 58 , 1437 (1987)). The third transition at about 70°C below the bulk melting point is detected for the first time.

The growth of silver on Si(111) is reexamined and new experiments are carried out using the method of isothermal desorption spectroscopy with AES. A correlation between LEED patterns and AES data upon adsorption and desorption permits one to precise the domain of existence of both 3 × 1 and √3 phases (respectively completed at 1 3 and 2 3 of a monolayer) and therefore to draw a 2D phase diagram and propose new structural models. We extend a kinetic model proposed earlier for the case of desorption of 2D phases, to the desorption of 3D crystallites. We thus show that using a simple kinetic method, thermodynamic parameters may be directly derived, namely the cohesive energy and the vibrational frequency of each phase. The values obtained, close to the ones of bulk silver, are respectively: E = 68 kcalmole−1, ν = 2.3 × 1012s−1 for the 3 × 1 phase; E = 65 kcalmole−1, ν = 1.8 × 1012s−1 for the √3 phase; E = 67 kcalmole−1, ν = 4 × 1012s−1 for the 3D crystallites.

Since its first introduction by SMITH /1/ low-energy ion scattering has developed into a well-established method for investigating the composition and structure of solid surfaces. The specific features of the method lie in its sensitivity to the atomic masses in the topmost layer of a surface and in the capability to analyse the positions of these atoms relative to each other, i.e. to characterize the local atomic arrangement /2/.

The electronic properties of a clean Si(110)‐16×2 surface have been studied by angle resolved ultraviolet photoelectron spectroscopy (ARUPS) and surface differential reflectivity (SDR). Four surface states have been recognized by ARUPS and their dispersions have been mapped along the main symmetry lines in the surface Brillouin zone. SDR experiments revealed transitions between filled and empty surface states at ∼1.8, 2.4, and 2.9 eV. The results have been explained on the basis of a new structural model of the Si(110) 16×2 phase using adatoms, rest atoms and dimers as building blocks similarly to the case of the Si(111) 7×7 dimer‐adatom‐stacking fault (DAS) model.