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Peter Heeg

Publications and source records attributed to Peter Heeg.

7 recordsLinked to original sources
PubMed2006

Evaluation of two methods of determining the efficacies of two alcohol-based hand rubs for surgical hand antisepsis.

The antimicrobial efficacies of preparations for surgical hand antisepsis can be determined according to a European standard (prEN 12791 [EN]) and a U.S. standard (tentative final monograph for health care antiseptic drug products [TFM]). The U.S. method differs in the product application mode (hands and lower forearms, versus hands only in EN), the number of applications (11 over 5 days, versus a single application in EN), the sampling times (0, 3, and 6 h after application, versus 0 and 3 h in EN), the sampling methods (glove juice versus fingertip sampling in EN), and the outcome requirements (absolute bacterial reduction factor [RF], versus noninferiority to reference treatment in EN). We have studied the efficacies of two hand rubs according to both methods. One hand rub was based on 80% ethanol and applied for 2 min, and the other one was based on 45% propan-2-ol, 30% propan-1-ol, and 0.2% mecetronium etilsulfate and applied for 1.5 min. The ethanol-based hand rub was equally effective as the 3-min reference disinfection of prEN 12791 in both the immediate (RFs, 2.97 +/- 0.89 versus 2.92 +/- 1.03, respectively) and sustained (RFs, 2.20 +/- 1.07 versus 2.47 +/- 1.25, respectively) effects. According to TFM, the immediate effects were 2.99 log10 (day 1), 3.00 log10 (day 2), and 3.43 log10 (day 5), and bacterial counts were still below baseline after 6 h. The propanol-based hand rub was even more effective than the reference disinfection of prEN 12791 in both the immediate (RFs, 2.35 +/- 0.99 versus 1.86 +/- 0.87, respectively) and sustained (RFs, 2.17 +/- 1.00 versus 1.50 +/- 1.26, respectively) effects. According to TFM, the immediate effects were 2.82 log10 (day 1), 3.29 log10 (day 2), and 3.25 log10 (day 5), and bacterial counts were still below baseline after 6 h. Some formulations have been reported to meet the efficacy requirements of one of the methods but not those of the other. That is why we conclude that, despite our results, meeting the efficacy requirements of one test method does not allow the claim that the requirements of the other test method are also met.

Disinfectants↗
PubMed2004

[Conception of heavy ion beam therapy at Heidelberg University (HICAT)].

The ion beam therapy facility HICAT presently under construction at the Heidelberg University Clinic will be the first clinical irradiation facility for heavy ions in Europe. Its capacity should enable the treatment of 1000 patients per year. The use of different ion species ranging from protons to oxygen under identical conditions should clarify the question of which particle species is best suited in terms of indication. A synchrotron will accelerate the particles to energies corresponding to water-equivalent ranges from 2 cm to 30 cm. An intensity-controlled raster scanning technique will be used to optimize the use of the favorable depth dose distribution of ions. The planned heavy-ion gantry will be the first world-wide. The facility should be complete in 2006.

Equipment Design↗
PubMed2004

Surveillance of Pseudomonas aeruginosa-isolates in a neonatal intensive care unit over a one year-period.

Outbreaks of gram-negative bacteria such as Pseudomonas aeruginosa in neonatal intensive care units (NICU) can be life-threatening to pre-term infants, which are highly susceptible to serious infections with bacteria. Forty-two ventilated neonates in the NICU of the University Children's Hospital of Tuebingen were found to be colonized (n = 40) or infected (n = 2) with P. aeruginosa within a sampling period of one year. To investigate the colonization patterns and identify potential outbreak sources, epidemiological investigations, environmental surveillance and typing by serotyping and pulsed-field gel electrophoresis of the recovered isolates were performed. The investigation demonstrated a genetically related cluster of P. aeruginosa isolates during the surveillance period in 39 neonates and a second cluster at the end of the period in two neonates. A third strain representing a genetically distinct group was found in only one patient. Environmental investigations demonstrated the presence of P. aeruginosa in the ventilation equipment of 22 patients: binasal prongs (n = 22), water reservoir (n = 9), and heater (n = 1). In one case, P. aeruginosa was found in breast milk. Other environmental investigations revealed no P. aeruginosa. Although no evidence for a unique source was found, a series of intervention steps were initiated by the NICU personnel, medical microbiologists and infection control experts. The intervention steps included reinforced training of health care staff and a change from chemical to thermal disinfection of binasal prongs. Implementation of these measurements successfully stopped the recurrent occurrence of P. aeruginosa colonization.

Cross Infection↗
PubMed2004

Two episodes of vancomycin-resistant Enterococcus faecium outbreaks caused by two genetically different clones in a newborn intensive care unit.

In 2001 two outbreak episodes (January-March and June-July) caused by vancomycin-resistant E. faecium (VRE) of the VanA-type were observed at a neonatal intensive care unit (NICU) of a university hospital in south-west Germany. To identify the initial source and the route of transmission environmental samples were examined as well as stool samples from patients and the staff. VRE was not found in environmental samples. However, stool samples from 24 hospitalised children tested positive and bacterial clonality was assessed by Sma1-based macro restriction analysis. Furthermore, esp gene and vancomycin resistance gene carriage were examined as well as bacteriocin production. PCR analysis showed that all 24 isolates carried vanA gene cluster, encoding resistance to vancomycin and teicoplanin. However, five of the vanA-positive isolates were resistant to vancomycin but not to teicoplanin. Only these five isolates produced bacteriocin, but in none of the isolates esp gene was detected. PFGE revealed that both outbreaks were caused by two different clones. The patient initiating the first episode, was identified whereas the origin of the second episode remained unknown. From one of the 40 staff stool samples VRE was isolated. This strain was related to the clone of the summer outbreak. In conclusion there were two independent episodes of self limiting VRE outbreaks and transmission on the ward is highly probable.

Bacterial Proteins↗
PubMed2004

Infectivity of prion protein bound to stainless steel wires: a model for testing decontamination procedures for transmissible spongiform encephalopathies.

OBJECTIVES: To establish an animal model to study transmissible spongiform encephalopathy using hamsters and steel wires contaminated with infectious brain materials as transfer vehicles, and, based on this model, to test decontamination procedures against the infectious prion proteins on the steel wires as a near real situation bioassay. DESIGN: Infectious brain materials were given to healthy hamsters intracerebrally either as a suspension or as dried materials on the surface of steel wires. The animals were observed for 18 months. During this period, animals showing definitive clinical signs were euthanized. Decontamination studies were performed by reprocessing contaminated steel wires with different disinfection agents and procedures before implantation. RESULTS: Pathological prion proteins were able to bind to the steel wires and caused disease after the contaminated wires were implanted in the brains of hamsters. When the contaminated wires were treated with different reprocessing procedures before implantation, infectivity was reduced, which was manifested directly by prolonged survival time of the test animals. These results show that this model can be used as a bioassay to validate reprocessing procedures for surgical instruments. CONCLUSIONS: At the time of submission of this article, only the group of hamsters incubated with wires reprocessed with an alkaline detergent, followed by sterilization with a modified cycle in a hydrogen peroxide gas plasma sterilizer (4 injections), showed no clinical signs of disease and remained alive. Two animals from the group receiving sodium hydroxide followed by autoclaving (at 134 degrees C for 18 minutes) died. Furthermore, the tested enzymatic cleaning agent seemed to have no positive effect.

Animals↗
PubMed2002

[Clinical dosimetry for heavy ion therapy].

Since December 1997, patients are treated with carbon ions at GSI (Gesellschaft für Schwerionenforschung). Dose delivery is performed with the intensity-controlled raster-scanning technique, which allows a highly conformal treatment of the tumor. To meet the special requirements of dosimetry with heavy ion beams, new dosimetric measurement techniques were developed and introduced into clinical application by the DKFZ (Deutsches Krebsforschungszentrum). The techniques comprise calibration of the irradiation monitor, checks of lateral and depth dose profiles, as well as verification of the beam delivery for complex three-dimensional dose distributions. The developed dosimetric methods are now integral part of clinical application and enable safe treatment with carbon ion therapy.

Heavy Ion Radiotherapy↗