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Biomedical subjects

H K Geiss

Publications and source records attributed to H K Geiss.

At least 55 records · Page 3Linked to original sources
PubMed1994

Prevention of bacterial colonization of intravenous catheters by antiseptic impregnation of polyurethane polymers.

The use of intravascular catheters is associated with infectious complications. Using plastic materials with antibacterial activity may reduce catheter-related bacterial colonization. A novel intravascular catheter impregnated with the antiseptics silver-sulphadiazine and chlorhexidine was tested in an in-vivo model using implantation of catheters into the internal jugular veins of rats. The rate and magnitude of bacterial colonization in groups with implantation of silver-sulphadiazine and chlorhexidine bonded (SSC) and control (C) catheters were assessed 3 and 7 days after intravenous implantation, and local challenge at the exit site by 10(7) cfu Staphylococcus epidermidis ATCC 35984. Significant reductions in the culture positivity of catheters were observed in the test compared with control groups. After 3 and 7 days, the magnitude of bacterial colonization of implanted catheter segments was significantly lower compared with control catheters (P < 0.01). These findings indicate that antiseptic-bonded catheters substantially reduce the incidence and magnitude of catheter-related bacterial colonization, and may subsequently reduce catheter-related infection.

Animals↗
PubMed1994

A novel test model for routine microbiological control of automated washer/disinfectors for flexible endoscopes.

Concerns exist about effective methods for endoscope cleaning, disinfection and sterilization. The aim of this study was to establish a model for controlling the function of automatic washer/disinfectors for flexible endoscopes under routine conditions. The team developed a dummy endoscope channel system representing two complete gastroscopes and a colonoscope, with channels joined together and fitted with adaptors to allow the models to fit into different washer/disinfectors. The models were artificially contaminated with various combinations of four test organisms and coagulating blood and run through test cycles in different washer/disinfectors. A total of 24 test runs were performed. The reduction of a given microbial burden by at least five log steps is an established measure of efficacy of a decontamination procedure. When the two challenge tests (45 channels) and the six positive controls are excluded, only 13/309 channels (4.2%) failed the proof of efficacy. In contrast, the failure rate in the challenge test was 65.3%. The difference of the final bioburden is statistically significant. The data suggest this test model could be regarded as a first step in rational and reliable biological control of flexible endoscope reprocessing.

Central Supply, Hospital↗
PubMed1994

New sterilisation technologies--are they applicable for endoscopic surgical instruments?

It has been well established that instruments for minimally invasive surgery (MIS) must be treated like ordinary surgical instruments when they are intended for use within sterile areas of the human body. Due to the special design of most MIS instruments autoclaving (i.e. application of heat) may damage these delicate items. Therefore, low temperature sterilisation processes are essential. Gas sterilisation with ethylene oxide and formaldehyde may pose significant health hazards to workers exposed to these gases and to patients due to residues remaining on the surface of the instruments. Their general use in hospitals is more and more discouraged. However, with the advent of hydrogen peroxide gas plasma sterilisation there is a true alternative available for the sterilisation of MIS instruments. In contrast, the use of immersion sterilants such as liquid glutaraldehyde or peracetic acid cannot be considered as adequate because it is almost impossible to keep the processed instruments sterile until their intended use.

Endoscopes↗
PubMed1993

Prevention of catheter-related infections by antiseptic bonding.

A novel catheter pretreated with the antiseptics chlorhexidine and silver-sulfadiazine, designed to reduce catheter-related colonization and infection, was tested in both in vitro and in vivo studies. In vitro experiments demonstrated the long-lasting antibacterial properties of this catheter. For the in vivo study a total of 40 rats divided into different experimental groups were used. Colonization rates of both antiseptic bonded (AS) and control (C) catheters were assessed either three (-3) or seven (-7) days after implantation and local challenge using live Staphylococcus epidermidis ATCC 35984 with 10(7) colony-forming units (cfu) per inoculum. At the time of removal, catheters, organ specimens, and blood samples were taken for cultivation. Significant reductions in the magnitude of colonization of the antiseptic catheters by the test organism were observed in all groups. The average number of cfu colonizing control segments exceeded those found on the treated catheter segments by log 3 (C3/AS3) and log 5 (C7/AS7), respectively (C3: 1.2 x 10(6) +/- 4.1 x 10(5) cfu/segment and AS3: 1.8 x 10(3) +/- 6.6 x 10(2); C7: 2.7 x 10(5) +/- 8.6 x 10(4) and AS7: 1.1 +/- 0.7; mean +/- standard error of the mean, all differences between matching groups statistically significant, Wilcoxon rank sum test, P < 0.0001). These data suggest that antiseptic catheters may substantially decrease the magnitude of catheter-related microbial colonization and subsequent catheter-related infections and may offer a more effective alternative to current methods.

Animals↗
PubMed1993

[Food borne outbreak of a Salmonella enteritidis epidemic in a large pharmaceutical industry].

In summer 1991 an outbreak of a Salmonella enteritidis epidemic involving about 600 cases of gastroenteritis occurred at one of the leading pharmaceutical companies in southwestern Germany. The main source was a cold fruit soup, in addition Salmonella were isolated from meat strips and a curd cheese which were used for a salad dressing. A total of 2300 contaminated food portions were served resulting in an attack rate of about 25%. The possible origin could have been an asymptomatic Salmonella-positive member of the kitchen personnel who was the only one who was involved with the preparation of all the incriminated foods. A further spread of the epidemic and especially the possible contamination of pharmaceuticals was avoided by the timely and adequate reaction of the company's occupational medical service. This case exemplifies how classical crisis management, "increased initiative on one's own for prevention of infections in all areas of food processing" (Steuer) and finally the cooperation of the company with different institutions of the public health authorities contribute to the control of such a catastrophic scenario.

Adult↗
PubMed1992

Evaluation of a new commercial system for the identification of Enterobacteriaceae and non-fermentative bacteria.

The performance of a new commercial semi-automatic system (Cobas Micro, Becton Dickinson) for identification of gram-negative fermentative and non-fermentative bacilli was evaluated using strains of clinical origin belonging to 48 different species. Two groups of strains were tested: 510 strains using a long incubation period (21 hours) and 158 strains using a short incubation period (5 hours). The correct identification rate without additional tests was 95.5% and 94.3% for the tests using a long and short incubation period respectively. The findings suggest that the system is highly accurate in the identification of most clinically important gram-negative rods, but shows some shortcomings in the identification of non-fermentative bacteria. The system is easy to use, and with some changes in the database and the inclusion of gram-positive and anaerobic bacteria would offer a valuable alternative to currently available automatic identification systems.

Bacteriological Techniques↗
PubMed1992

Safety of a guidewire technique for replacement of pulmonary artery catheters.

The purpose of this study was to determine if a guidewire change from a pulmonary artery catheter (PAC) to a central venous catheter (CVC) poses a significant infection risk. A total of 128 consecutive cardiac surgical patients with PACs inserted in the operating room were entered into this study. Postoperatively, patients were randomly allocated to receive a double-lumen CVC, either at the initial introducer insertion site over a guidewire, or at a new site with de novo catheterization. The tips of all introducers, PACs, and CVCs were cut off, cultured, and semi-quantitatively analyzed. The results show that insertion of CVCs over a guidewire within 48 hours after initial venapuncture is no more likely to be associated with catheter colonization than is de novo percutaneous insertion at a different site. From 48 hours up to 72 hours following initial insertion of the PAC, an incidence of catheter-related infection of 35.3% was observed in the guidewire group, as opposed to 12.5% in the de novo group. It is recommended that the use of a guidewire technique for catheter replacement (PAC to CVC) is a safe alternative to de novo insertion of a CVC within 48 hours after initial insertion of the PAC. In order to minimize the potential risk of catheter-related infection and bacteremia in cardiac surgical patients, de novo catheterization beyond 48 hours after initial venapuncture is suggested.

Bacteremia↗
PubMed1992

Nosocomial sinusitis in ventilated patients. Nasotracheal versus orotracheal intubation.

A total of 68 postoperative patients whose lungs were ventilated for more than 4 days were studied prospectively during a one-year study period to investigate the effect of the mode of intubation on the paranasal sinuses. After an initial X ray of the skull showing no pathological findings, patients were assigned randomly to one of the study groups; the lungs of patients in group A were ventilated via an orotracheal tube (n = 32), and patients in group B via a nasotracheal tube (n = 36). X ray examinations of the sinuses were performed at regular intervals. Diagnosis of sinusitis was confirmed by transantral needle puncture and culture of fluids obtained. Antibiotic regimens were altered according to laboratory testing. Two patients in group A developed signs of sinusitis in comparison to 15 patients in group B (p less than 0.01). However, there were significantly more airway complications in the orotracheal group, particularly during the period of weaning from ventilation. We conclude that orotracheal intubation should be preferred as the routine route of intubation.

Aged↗
PubMed1992

Infectious risk of replacing venous catheters by the guide-wire technique.

During the perioperative period cardiac surgical patients are often monitored by pulmonary artery (PA) catheters. This catheter, which is floated through the right heart into the pulmonary artery, enables the intensivist to measure and calculate indices of myocardial performance. After a variable period of time this invasive monitoring can often be abandoned following cardiovascular stabilization in these patients, but patients usually still require a central venous (CV) access for diagnostic and therapeutic purposes. To place this CV catheter either a de novo puncture at a new site or a guide-wire change at the existing exit site through the PA catheter in place can be performed. Each de novo puncture is associated with a risk of traumatising internal vessels or organs. In contrast, guide-wire change avoids this risk but inherits a potential risk of transferring bacteria by manipulation of contaminated lines. Our study included 159 consecutive cardiac surgical patients in whom PA monitoring was established preoperatively and terminated within a period of up to 72 hours postoperatively. At random the PA catheter was replaced by a CV line either by de novo puncture or by guide-wire change. All CV lines were left in place for 7 days according to standard practice in our intensive care unit (ICU). After removal of CV catheters all catheter tips were cultured semiquantitatively by rollplate technique according to Maki (26) and subsequent immersion broth culture. A positive culture was defined as growth of one up to 15 colonies on the agar-plate or any microbial growth in the broth. A significant colonization was assumed in catheters yielding more than 15 colony forming units (cfu) on the blood agar plate (26). Our results show a significant risk of colonization and catheter-related infection associated with the guide-wire technique as opposed to the de novo puncture. The figures for relevant colonization were 33.3% in the guide-wire group as opposed to 10.5% in the de novo group. However, this difference was noted only in the subgroup in which replacement of PA catheters by CV catheters was performed beyond 48 h after initial insertion of PA catheters. Within the time intervals of 24 and 25 to 48 h, respectively, we could not detect any significant difference between groups.

Aged↗
PubMed1991

Media and methods for isolation of aeromonads from fecal specimens. A multilaboratory study.

An international multilaboratory study was conducted to establish the optimal combination of culture media, incubation time and temperature for recovery of aeromonads from stools using blood ampicillin (10 mg/l) agar (BAA), starch ampicillin (10 mg/l) agar (SAA), and cefsulodin irgasan novobiocin agar (CIN) with alkaline peptone water (APW) for enrichment. Optimal recovery of aeromonads (167/186) occurred using BAA (37 degrees C; 24 h) and CIN (25 degrees C; 48 h) with APW (25 degrees C; 24 h) subcultured to BAA (37 degrees C; 24 h) and CIN (25 degrees C; 48 h).

Aeromonas↗
PubMed1991

[Hygiene barriers in the hospital--infectious aspects].

Barriers against hospital hygiene as an integral part of patient treatment are not at all a new phenomenon, as the example of Semmelweis shows. However, it is surprising, that even today sometimes negative statements of clinicians concerning the role of hospital hygiene don't differ significantly from those mentioned in the last century. The reason for this, however, has to be sought as well in our own failures. Especially in Germany, during the last decades hospital hygienists put the emphasize too much on scientific problems, which, in the clinicians view had no direct relevance to patient care. We were often not aware that the requirements of optimal infection control have changed, due to the increasing number of patients, whose infection risks varied greatly from those of former days. The meaning of hospital hygiene is more than routine checks of proper handwashing or control of bacteriological contamination, but needs a specialist well knowledgeable in the field of prevention, diagnosis and therapy of nosocomial diseases. However, these expectations could only be fulfilled if the hospital hygienist returns to the patient's bedside, thus cooperatively discussing together with the clinician all infectious and hygienic problems. This will be the only way, how the image of the hygienist as a policeman could be eradicated and hospital hygiene could be established as a self-evident and indispensable part of hospital patient care.

Cross Infection↗
PubMed1990

Detection and analysis of two serotypes of ammonia-oxidizing bacteria in sewage plants by flow cytometry.

Two different serotypes of the genus Nitrosomonas were isolated from samples of the sewage plant Heidelberg. These nitrifiers were enumerated in activated sludge of various other sewage plants after immunofluorescent labeling and staining with propidium iodide by flow cytometry. The concentrations of these serotypes of Nitrosomonas spp. were in the range of 0.1 to 2%. Also, a test for the determination of the activity of ammonia-oxidizing bacteria was developed. Nitrite-oxidizing bacteria were specifically inhibited with sodium chlorate, and the activity of ammonia-oxidizing bacteria could be calculated from the increase of nitrite. Concentrations and activities of ammonia oxidizers were measured for a period of 6 months in the sewage plant Heidelberg. With one exception, activities and concentrations of ammonia-oxidizing bacteria decreased and increased in parallel.

Ammonia↗