Results from the First 12 Months of the National Surveillance of Healthcare Associated Outbreaks in Germany, 2011/2012

Background

In August 2011, the German Protection against Infection Act was amended, mandating the reporting of healthcare associated infection (HAI) outbreak notifications by all healthcare workers in Germany via local public health authorities and federal states to the Robert Koch Institute (RKI).

Objective

To describe the reported HAI-outbreaks and the surveillance system’s structure and capabilities.

Methods

Information on each outbreak was collected using standard paper forms and notified to RKI. Notifications were screened daily and regularly analysed.

Results

Between November 2011 and November 2012, 1,326 paper forms notified 578 HAI-outbreaks, between 7 and 116 outbreaks per month. The main causative agent was norovirus (n = 414/578; 72%). Among the 108 outbreaks caused by bacteria, the most frequent pathogens were Clostridium difficile (25%) Klebsiella spp. (19%) and Staphylococcus spp. (19%). Multidrug-resistant bacteria were responsible for 54/108 (50%) bacterial outbreaks. Hospitals were affected most frequently (485/578; 84%). Hospital outbreaks due to bacteria were mostly reported from intensive care units (ICUs) (45%), followed by internal medicine wards (16%).

Conclusion

The mandatory HAI-outbreak surveillance system describes common outbreaks. Pathogens with a particular high potential to cause large or severe outbreaks may be identified, enabling us to further focus research and preventive measures. Increasing the sensitivity and reliability of the data collection further will facilitate identification of outbreaks able to increase in size and severity, and guide specific control measures to interrupt their propagation.     

Genome Scale Reconstruction of a Salmonella Metabolic Model: COMPARISON OF SIMILARITY AND DIFFERENCES WITH A COMMENSAL Escherichia coli STRAIN*

Salmonella are closely related to commensal Escherichia coli but have gained virulence factors enabling them to behave as enteric pathogens. Less well studied are the similarities and differences that exist between the metabolic properties of these organisms that may contribute toward niche adaptation of Salmonella pathogens. To address this, we have constructed a genome scale Salmonella metabolic model (iMA945). The model comprises 945 open reading frames or genes, 1964 reactions, and 1036 metabolites. There was significant overlap with genes present in E. coli MG1655 model iAF1260. In silico growth predictions were simulated using the model on different carbon, nitrogen, phosphorous, and sulfur sources. These were compared with substrate utilization data gathered from high throughput phenotyping microarrays revealing good agreement. Of the compounds tested, the majority were utilizable by both Salmonella and E. coli. Nevertheless a number of differences were identified both between Salmonella and E. coli and also within the Salmonella strains included. These differences provide valuable insight into differences between a commensal and a closely related pathogen and within different pathogenic strains opening new avenues for future explorations.Salmonella is a major cause of human and animal enteric disease. Salmonella consists of two species, bongori and enterica, and the latter can be further divided into subspecies (I-VI). The majority of human and animal infections are caused by S. enterica subspecies I, of which Salmonella typhimurium and Salmonella enteritidis are the most prevalent causes of human inflammatory gastroenteritis, often referred to as food poisoning (1). The recent availability of genome sequences of bacterial pathogens, including Salmonella, provides an opportunity to interrogate these organisms using a systems biology approach. By contrasting the genotype-phenotype relationship of pathogens such as Salmonella against closely related commensals such as an Escherichia coli K12 insights can be revealed into how these pathogens have adapted to their environmental niche(s). Salmonella and E. coli K12 share ∼85% of their genome (2–6). DNA microarray and genome sequencing studies have highlighted regions of the genome that are conserved between these closely related bacteria and those that are different. Many of the differences are attributable to the acquisition of virulence factors, although a significant proportion of their genome codes is for metabolic genes (2–8).A genome scale model consists of a stoichiometric reconstruction of all reactions known to act in the metabolism of an organism along with a set of accompanying constraints on the flux of each reaction in the system (9, 10). These models define the organism''s global metabolic space, network structural properties, and flux distribution potential (9, 10). Therefore constraint-based models can help predict cellular phenotypes given particular environmental conditions. Genome scale models have been useful in understanding the metabolic properties of a variety of organisms including E. coli, Bacillus subtilis, Pseudomonas putida, and Lactobacillus (9–12). Genome scale models can be validated in various ways such as continuous culture experiments, substrate utilization assays, specific gene mutations, and isotopic carbon measurements. The high through-put phenotype microarray (PM)³ system that is available through Biolog (Hayward, CA) is ideal to use for substrate utilization assays as it provides a comprehensive large-scale phenotyping technology to assess gene function at the cellular level (13).The aim of this work was to construct a Salmonella genome scale model. The model highlights the similarities and differences between pathogenic bacteria such as S. typhimurium and S. enteritidis and the commensal E. coli K12 laboratory strains. The model was validated using the PM system and literature-derived (i.e. bibliomic) information. The substrate utilization assays also highlighted current knowledge gaps that will require further experimental data that can be used in the future for refining and extending the model.     

MATE CHOICE FOR NONADDITIVE GENETIC BENEFITS CORRELATE WITH MHC DISSIMILARITY IN THE ROSE BITTERLING (RHODEUS OCELLATUS)

Good genes models of mate choice predict additive genetic benefits of choice whereas the compatibility hypothesis predicts nonadditive fitness benefits. Here the Chinese rose bitterling, Rhodeus ocellatus, a freshwater fish with a resource‐based mating system, was used to separate additive and nonadditive genetic benefits of female mate choice. A sequential blocked mating design was used to test female mate preferences, and a cross‐classified breeding design coupled with in vitro fertilizations for fitness benefits of mate choice. In addition, the offspring produced by the pairing of preferred and nonpreferred males were reared to maturity and their fitness traits were compared. Finally, the MHC DAB1 gene was typed and male MHC genotypes were correlated with female mate choice. Females showed significant mate preferences but preferences were not congruent among females. There was a significant interaction of male and female genotype on offspring survival, rate of development, growth rate, and body size. No significant male additive effects on offspring fitness were observed. Female mate preferences corresponded with male genetic compatibility, which correlated with MHC dissimilarity. It is proposed that in the rose bitterling genetic compatibility is the mechanism by which females obtain a fitness benefit through mate choice and that male MHC dissimilarity, likely mediated by odor cues, indicates genetic compatibility.     

Effect of Guanosine 5''-O-(3-Thiotriphosphate) and Calcium on γ-Aminobutyric AcidB Binding as a Function of Postnatal Development

We have examined the development of gamma-aminobutyric acidB (GABAB) receptors in rat cerebrum using a binding assay that has achieved specific binding levels of approximately 50% with the GABAB ligand (-)-[3H]baclofen. As early as postnatal day 1, GABAB receptors are present and are linked to both calcium- and guanosine triphosphate-binding protein (G protein)-regulatory sites, as indicated by the stimulation of binding by calcium and the inhibition of binding by the guanine nucleotide guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S). However, whereas the EC50 for the calcium effect was at a mature value in the neonate, the IC50 for the inhibition of binding by GTP gamma S was not, and declined more than two orders of magnitude by adulthood. Moreover, while many previous studies had shown that manipulation of G proteins by guanine nucleotides affects receptors affinity rather than density, our saturation analysis of binding suggests that calcium affected GABAB receptor density rather than affinity. The results therefore suggest that calcium and the manipulation of G proteins by GTP gamma S may affect the GABAB receptor by different mechanisms.     

Glucose-6-phosphate dehydrogenase and malate dehydrogenase enzyme electrophoretic patterns amongst strains of Bacteroides fragilis

Fifty-two strains of Bacteroides fragilis were examined for their enzyme electrophoretic patterns of glucose-6-phosphate dehydrogenase (G6PDH) and malate dehydrogenase (MDH). All strains tested possessed high levels of both enzymes but the G6PDH reduced NADP whereas MDH was NAD-dependent. Twenty-seven strains produced single bands of both G6PDH and MDH. In all cases G6PDH migrated faster than MDH. Strains clustered by a single linkage algorithm were recovered in eight clusters at the 77% similarity level. The remaining 25 strains produced multiple bands of one or both enzymes. These were recovered in six clusters at the 72% similarity level using the same algorithm. The results of this study revealed considerable heterogeneity of enzyme patterns within B. fragilis.     

Distribution of Anthropometric Variables and the Prevalence of Obesity in Populations of West African Origin: The International Collaborative Study on Hypertension in Blacks (ICSHIB)

A survey of the prevalence of hypertension and associated risk factors including obesity was carried out among persons of West African heritage currently living in societies at different stages of social, economic and technological development. We present here the distribution of several anthropometric variables and the prevalence of obesity in these populations. Using a standard protocol with centralized training of field staff, 7 439 men and women aged 24 to 75 from six multinational sites were recruited and examined. Although men were taller, women were more obese across sites. Body mass index (BMI) and consequently the prevalence of overweight and obesity increased with westernization from rural African subsistence farming communities to suburban Chicago. Average BMI increased with age until about age 54, and then began to decline or at least level off. The mean BMI for African-American men and women was 27.1 kg/m² and 30.8 kg/m², respectively. Men displayed high levels of centripetal fatness, measured as the waist-to-hip ratio (WHR), compared to the women across site. Based on the US Department of Agriculture guidelines, 22.6% and 56.9% of the African-American men and women had elevated WHR. Although account must be taken of the important contribution of an individual's genetic background, this multinational study of persons with similar heritage clearly shows the potent impact of current environmental factors on the distribution and level of obesity.     

Construction of random sheared fosmid library from Chinese cabbage and its use for Brassica rapa genome sequencing project

As a part of the Multinational Genome Sequencing Project of Brassica rapa,linkage group R9 and R3 were sequenced using a bacterial artificial chromosome(BAC) by BAC strategy.The current physical contigs are expected to cover approximately 90%euchromatins of both chromosomes.As the project progresses,BAC selection for sequence extension becomes more limited because BAC libraries are restriction enzyme-specific.To support the project,a random sheared fosmid library was constructed.The library consists of 9...