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Hospital-acquired Infections (hospital-acquired + infections)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Common infections in diabetes: pathogenesis, management and relationship to glycaemic control

DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 1 2007
Anton Y. Peleg
Abstract Specific defects in innate and adaptive immune function have been identified in diabetic patients in a range of in vitro studies. However, the relevance of these findings to the integrated response to infection in vivo remains unclear, especially in patients with good glycaemic control. Vaccine efficacy seems adequate in most diabetic patients, but those with type 1 diabetes and high glycosylated haemoglobin levels are most likely to exhibit hypo-responsiveness. While particular infections are closely associated with diabetes, this is usually in the context of extreme metabolic disturbances such as ketoacidosis. The link between glycaemic control and the risk of common community-acquired infections is less well established but could be clarified if infection data from large community-based observational or intervention studies were available. The relationship between hospital-acquired infections and diabetes is well recognized, particularly among post-operative cardiac and critically ill surgical patients in whom intensive insulin therapy improves clinical outcome independent of glycaemia. Nevertheless, further research is needed to improve our understanding of the role of diabetes and glycaemic control in the pathogenesis and management of community- and hospital-acquired infections. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Microbial interactions and differential protein expression in Staphylococcus aureus ,Candida albicans dual-species biofilms

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2010
Brian M. Peters
Abstract The fungal species Candida albicans and the bacterial species Staphylococcus aureus are responsible for a majority of hospital-acquired infections and often coinfect critically ill patients as complicating polymicrobial biofilms. To investigate biofilm structure during polymicrobial growth, dual-species biofilms were imaged with confocal scanning laser microscopy. Analyses revealed a unique biofilm architecture where S. aureus commonly associated with the hyphal elements of C. albicans. This physical interaction may provide staphylococci with an invasion strategy because candidal hyphae can penetrate through epithelial layers. To further understand the molecular mechanisms possibly responsible for previously demonstrated amplified virulence during coinfection, protein expression studies were undertaken. Differential in-gel electrophoresis identified a total of 27 proteins to be significantly differentially produced by these organisms during coculture biofilm growth. Among the upregulated staphylococcal proteins was l -lactate dehydrogenase 1, which confers resistance to host-derived oxidative stressors. Among the downregulated proteins was the global transcriptional repressor of virulence factors, CodY. These findings demonstrate that the hyphae-mediated enhanced pathogenesis of S. aureus may not only be due to physical interactions but can also be attributed to the differential regulation of specific virulence factors induced during polymicrobial growth. Further characterization of the intricate interaction between these pathogens at the molecular level is warranted, as it may aid in the design of novel therapeutic strategies aimed at combating fungal,bacterial polymicrobial infection. [source]

Crystal structure of Staphylococcus aureus tyrosyl-tRNA synthetase in complex with a class of potent and specific inhibitors

PROTEIN SCIENCE, Issue 10 2001
Xiayang Qiu
TyrRS, tyrosyl-tRNA synthetase; bsTyrRS, Bacillus stearothermophilus TyrRS; YRS, Staphylococcus aureus tyrosyl-tRNA synthetase; YRStr, C-terminal domain truncated YRS; bsTyrRStr, C-terminal domain truncated bsTyrRS Abstract SB-219383 and its analogues are a class of potent and specific inhibitors of bacterial tyrosyl-tRNA synthetases. Crystal structures of these inhibitors have been solved in complex with the tyrosyl-tRNA synthetase from Staphylococcus aureus, the bacterium that is largely responsible for hospital-acquired infections. The full-length enzyme yielded crystals that diffracted to 2.8 Å resolution, but a truncated version of the enzyme allowed the resolution to be extended to 2.2 Å. These inhibitors not only occupy the known substrate binding sites in unique ways, but also reveal a butyl binding pocket. It was reported that the Bacillus stearothermophilus TyrRS T51P mutant has much increased catalytic activity. The S. aureus enzyme happens to have a proline at position 51. Therefore, our structures may contribute to the understanding of the catalytic mechanism and provide the structural basis for designing novel antimicrobial agents. [source]

Feasible identification of Staphylococcus,epidermidis using desferrioxamine and fosfomycin disks,

APMIS, Issue 1 2008
ANA LÚCIA SOUZA ANTUNES
Coagulase-negative Staphylococcus spp. (CoNS) have emerged as predominant pathogens in hospital-acquired infections, as well as reservoirs of antimicrobial resistance, increasing the necessity of developing reliable methods for identification of the most frequent species. The aim of this study was to propose a simplified method for identification of Staphylococcus epidermidis. A total of 490 isolates of CoNS were identified by Bannerman's method. Taking into account distinct approaches for identification of S. epidermidis, among CoNS, we proposed the use of only two disks: desferrioxamine for the initial trial, and fosfomycin to match the final identification. Of the 320 isolates susceptible to desferrioxamine, Bannerman's method identified 238 S. epidermidis and 73 S. hominis, while we achieved identification of 239 S. epidermidis and 76 S. hominis. Compared to Bannerman's method, the method proposed here obtained a sensitivity of 99.5%, and had a positive predictor value of 99.2%. We also used a genotypic method for identification of S. epidermidis by polymerase chain reaction (PCR) targeting the tuf gene. In conclusion, the method proposed here has proved to be useful for the identification of S. epidermidis, the most frequent species of CoNS isolated from blood cultures in clinical microbiology laboratories. [source]

Monitoring of nosocomial invasive aspergillosis and early evidence of an outbreak using cumulative sum tests (CUSUM)

CLINICAL MICROBIOLOGY AND INFECTION, Issue 9 2010
J. Menotti
Clin Microbiol Infect 2010; 16: 1368,1374 Abstract In order to provide a statistically based evaluation of the incidence of invasive aspergillosis (IA) over time, we applied the cumulative sums (CUSUM) methodology, which was developed for quality control and has already been applied for the surveillance of hospital-acquired infections. Cases of IA were recorded during a 5-year period. Incidence rates of cases assumed to be hospital-acquired, i.e. nosocomial IA (NIA), were analysed using CUSUM tests. Relationships between NIA, fungal contamination and construction or renovation work were tested using time-series methods. Between January 2002 and December 2006, 81 cases of NIA were recorded. CUSUM analysis of NIA incidence showed no significant deviation from the expected monthly number of cases until August 2005, and then the CUSUM crossed the decision limit, i.e. identified a significant increase in NIA as compared with the reference period (January 2002 to December 2004). Up to April 2006, the learning-curve CUSUM stayed over its limit, supporting an ongoing outbreak involving 24 patients, and then it significantly decreased in May 2006. Follow-up after May 2006 indicated no out-of-control situation, supporting a return to the baseline situation. In haematology wards, significant links were found between NIA incidence and fungal contamination of several sites at each ward (mainly unprotected common sites). An environmental source of contamination could be suspected, but no significant relationship was found between NIA incidence and ongoing construction or renovation. In conclusion, the CUSUM test proved to be well suited for real-time monitoring of NIA and for early identification and follow-up of an outbreak. [source]