Prolonged hospital and community-based listeriosis outbreak caused by ready-to-eat scalded sausages.

Listeria monocytogenes is a foodborne bacterial pathogen. Immunocompromised patients are at higher risk of developing invasive listeriosis with high fatality rates. After notification of two patients with Listeria that had stayed in the same hospital (hospital A) before the onset of infection, we began an investigation to ascertain the extent of the outbreak, identify its source and prevent further infections. We conducted active case finding by contacting hospital A, reviewing medical records and retrospectively investigating listeriosis notifications from the German surveillance system (SurvNet). The kitchen (hospital A) and its meat supplier (company X) were inspected and environmental and food samples were taken for microbiological testing. All isolates of L. monocytogenes, together with patient and food-related isolates from Baden-Württemberg 2006 to 2008, were characterised by pulsed-field gel electrophoresis (PFGE). Altogether, 16 cases of listeriosis were identified. Serotype 4b with the indistinguishable PFGE patterns (AscI 17a/ApaI 10) was detected from nine patients, five environmental and three ready-to-eat scalded sausage samples from company X, and two food samples from hospital A. All 11 patient cases linked to hospital A were immunosuppressed and were regularly served food during their hospital stay. Ten of these patients received corticosteroids and proton pump inhibitors (PPIs). Five cases were fatal. Our investigations indicate that ready-to-eat scalded sausages from company X caused this outbreak of listeriosis. Hospital food suppliers should guarantee the absence of L. monocytogenes in ready-to-eat meat products, controlled through optimised quality assurance.

Survey and case-control study during epidemics of Puumala virus infection.

In Baden-Wuerttemberg, a federal state in south-west Germany, a large outbreak of 1089 laboratory-confirmed human Puumala virus (PUUV) infections occurred in 2007. We conducted a survey to describe the disease burden and a case-control study to identify risk factors for acquiring PUUV. Case-patients were interviewed about clinical outcome and both case-patients and randomly recruited controls were interviewed about exposure. We calculated matched odds ratios (mOR) using a conditional logistic regression model. Multivariable analysis of 191 matched case-control pairs showed that case-patients were more likely than controls to have seen small rodents/their droppings (mOR 1.9, 95% CI 1.2-3.0), cleaned utility rooms (mOR 1.8, 95% CI 1.0-3.4) and visited forest shelters (mOR 3.9, 95% CI 1.1-14.3). Two thirds of case-patients required hospitalization. During PUUV epidemics rodent control measures and use of protective equipment should be considered in utility rooms and shelters.

Emergence of hantavirus in South Germany: rodents, climate and human infections.

Human hantavirus (serotype Puumala) infections are prevalent throughout Europe. The bank vole is the main reservoir of the Puumala virus (PUUV). Between 2001 and 2006, the annual incidences in Germany ranged from 0.1 to 0.5 per 100,000 inhabitants. About half of the cases were reported from the state of Baden-Württemberg (BW) in southwest Germany. In 2007, 1,089 PUUV infections were reported from BW. This reflects an incidence of 10.1:100,000, which is more than 11 times higher than the mean incidence of the previous 6 years. Spatial analysis highlights incidences up to 90:100,000 in the most affected district. The winter season 2006/2007 showed an all time high in reported mean temperature. The previous summer and autumn led to a beech mast year, resulting in favourable feed conditions for bank voles in the winter season 2006/2007. The causes of the observed increase in PUUV infections in 2007 cannot be restricted to known cycles in the bank vole population. Favourable feed conditions, a mild winter and an early onset of spring may have influenced bank vole population size as well as human exposure to infectious rodent excretions. Further epidemiologic studies are necessary to better understand the interaction between environmental factors, occurrence of Puumala virus in bank voles and the risk for human disease.

Monomeric and dimeric amidinate complexes of magnesium.

Treatment of anhydrous magnesium bromide with 2 equiv of (1,3-di-tert-butylacetamidinato)lithium, (1,3-di-tert-butylbenzamidinato)lithium, (1,3-diisopropylacetamidinato)lithium, or (1-tert-butyl-3-ethylacetamidinato)lithium (prepared in situ from the corresponding carbodiimide and alkyllithium) in diethyl ether at ambient temperature afforded bis(N,N'-di-tert-butylacetamidinato)magnesium (81%), bis(N,N'-di-tert-butylbenzamidinato)magnesium (82%), bis[bis(N,N'-diisopropylacetamidinato)magnesium] (70%), or bis[bis(1-tert-butyl-3-ethylacetamidinato)magnesium] (93%), respectively, as colorless crystalline solids. These complexes were characterized by spectral and analytical data and by single-crystal X-ray crystallography for bis(N,N'-di-tert-butylbenzamidinato)magnesium, bis[bis(N,N'-diisopropylacetamidinato)magnesium], and bis[bis(1-tert-butyl-3-ethylacetamidinato)magnesium]. In the solid-state structure, bis[bis(1-tert-butyl-3-ethylacetamidinato)magnesium] was found to contain mu,eta(2):eta(1)-amidinato ligands. Bis[bis(N,N'-diisopropylacetamidinato)magnesium] exists in a monomer-dimer equilibrium in toluene-d(8) between -20 and +60 degrees C. A van't Hoff analysis of this equilibrium afforded DeltaH degrees = -14.7 +/- 0.2 kcal/mol, DeltaS degrees = -44.9 +/- 0.2 cal/(mol.K), and DeltaG degrees (298 K) = -1.32 +/- 0.2 kcal/mol. The potential application of the new compounds in the chemical vapor deposition of magnesium-doped group 13 compound semiconductor films is discussed.

Early transition metal complexes containing 1,2,4-triazolato and tetrazolato ligands: synthesis, structure, and molecular orbital studies.

Several early transition metal complexes bearing 1,2,4-triazolato and tetrazolato ligands have been prepared by reaction of the pyrazolato complexes Ti(tBu(2)pz)(4-x)Cl(x) (tBu(2)pz = 3,5-di-tert-butylpyrazolato; x = 1, 2) and M(tBu(2)pz)(5-x)Cl(x) (M = Nb, Ta: x = 2, 3) with the sodium or potassium salts derived from 1,2,4-triazoles and tetrazoles. The X-ray structure analysis of Ti(tBu(2)pz)(2)(Me(2)C(2)N(3))(2) shows eta(2)-coordination of the 1,2,4-triazolato ligands, while in Ti(tBu(2)pz)(3)(C(2)H(2)N(3)) and Nb(tBu(2)pz)(3)(Me(2)C(2)N(3))(2) the analogous groups are joined in a eta(1)-fashion in the solid-state structure. Solution NMR studies at different temperatures suggest transition states involving eta(2)-1,2,4-triazolato ligands for the complexes containing eta(1)-1,2,4-triazolato ligands in the solid state. X-ray crystal structures of analogous tetrazolato complexes Ti(tBu(2)pz)(3)(PhCN(4)) and Nb(tBu(2)pz)(3)(PhCN(4))(2) show eta(1)-coordination of the 2-nitrogen atoms of the tetrazolato ligands. Molecular orbital calculations have been carried out on several model titanium complexes and provide detailed insight into the bonding between early transition metal centers and 1,2,4-triazolato and tetrazolato ligands. The eta(2)-coordination mode of 1,2,4-triazolato and tetrazolato ligands is predicted to be more stable than the eta(1)-coordination mode by 13.8-5.2 kcal/mol.

Effects of unpaired cysteines on yield, solubility and activity of different recombinant antibody constructs expressed in E. coli.

New E. coli vectors based on the pOPE/pSTE vector system [Gene 128 (1993) 97] were constructed to express a single-chain Fv antibody fragment (scFv), a scFv-streptavidin fusion protein and two disulfide bond-stabilized Fv antibody fragments (dsFvs) utilizing different side chain positions for disulfide stabilization. All of these constructs encoded fusion proteins carrying five C-terminal histidine residues preceded by an unpaired cysteine. The influence of this cysteine, which was originally introduced to allow the chemical modification of the fusion proteins, was assessed by exchanging the two amino acids CysIle in front of the carboxy terminal His-tag to SerHis in all constructs. Yield and antigen-binding activity of the antibody constructs were compared after standard lab-scale periplasmic expression in Escherichia coli. The removal of the unpaired cysteine resulted in a significant increase in antigen-binding activity of the crude periplasmic extracts. Further, a three-five fold increase of yield and a significantly improved purity were observed after immobilized metal affinity chromatography (IMAC) with all four constructs.

Synthesis and characterization of calcium complexes containing eta 2-pyrazolato ligands.

Treatment of calcium bromide with 3,5-di-tert-butylpyrazolatopotassium (2 equiv) in tetrahydrofuran afforded Ca(tBu2pz)2(THF)2 (69%). The reaction of this compound with pyridine (3 equiv), tetramethylethylenediamine (TMEDA, 1 equiv), N,N,N',N',N"-pentamethyldiethylenetriamine (PMDETA, 1 equiv), triglyme (1 equiv), and tetraglyme (1 equiv) yielded Ca(tBu2pz)2(py)3 (51%), Ca(tBu2pz)2(TMEDA) (74%), Ca(tBu2pz)2(PMDETA) (50%), Ca(tBu2pz)2(triglyme) (73%), and Ca(tBu2pz)2(tetraglyme) (57%), respectively. Treatment of the tetrahydrofuran adduct of Ca(Me2pz)2, generated in situ, with PMDETA (1 equiv), triglyme (1 equiv), and tetraglyme (1 equiv) afforded Ca(Me2pz)2(PMDETA) (65%), Ca(Me2pz)2(triglyme) (54%), and Ca(Me2pz)2(tetraglyme) (40%), respectively. The X-ray crystal structures of Ca(tBu2pz)2(py)3, Ca(tBu2pz)2(TMEDA), Ca(tBu2pz)2(PMDETA), Ca(tBu2pz)2(triglyme), and Ca(Me2pz)2(PMDETA) revealed six-, seven-, or eight-coordinate calcium centers with eta 2-pyrazolato ligands. Ca(tBu2pz)2(triglyme) sublimes at 160 degrees C (0.1 mmHg). The potential utility of these complexes as source compounds for chemical vapor deposition processes is discussed.

Fatty acid composition of human milk triglyceride species. Possible consequences for optimal structures of infant formula triglycerides.

Human milk triglycerides (TGs) were separated into 14 fractions by silver ion high-performance liquid chromatography (HPLC) with light-scattering detection (LSD). Subsequent fractionation by reversed-phase HPLC-LSD resulted in 75 subfractions. The major 48 were analysed by gas chromatography for their intact TG and fatty acid (FA) compositions. Using a constrained non-linear optimization computer program, the FA compositions and abundances of 170 different TG combinations were calculated. The major two, 16:0/18:1/18:1 (11.8 mol%) and 16:0/18:1/18:2 (10.0 mol%), were almost twice as abundant as expected from random FA distribution. The apolarities of 16:0 and 18:0 seem to be modulated by unsaturated FAs (18:1, 18:2) or medium-chain FAs (MCFAs; 8:0-12:0). MCFAs were present in 19 mol%. Of these, 7.2 mol% are likely to harbour stereospecific structures with an MCFA at sn-3, 16:0 or 14:0 at sn-2, and 18:1 or 18:2 at sn-1. These structures are excellent substrates for lingual and gastric lipases, producing products that assist in duodenal TG lipolysis.