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.

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.

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.

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° C for 18 minutes) died. Furthermore, the tested enzymatic cleaning agent seemed to have no positive effect.

To investigate and evaluate the use of a portable luminometer system for detecting contamination following the reprocessing and high-level disinfection of flexible endoscopes.

Random sampling of endoscopes spaced at 1- to 2-week intervals following normal use in patients.

Portable luminometer system testing of 31 endoscopes undergoing reprocessing, 63 stored endoscopes, and 15 reprocessed endoscopes that underwent in-depth microbiological analysis. For testing with the portable luminometer system, samples were collected by swabbing a 100-cm2 shank surface area and the internal tip end orifice. Standardization of portable luminometer system results was performed in vitro by comparison of serial dilutions of known quantities of microorganisms and blood, tested before and after sterilization by autoclave. Microbiological analysis included Gram stain, culture for aerobic bacteria, and gene probes for Mycobacterium tuberculosis, herpes simplex viruses 1 and 2, and Cytomegalovirus. Trichrome and calcofluor white stains were used to detect parasites and fungi. Legionella was detected by stain with fluorescent-labeled monoclonal antibody.

The gastroendoscopy unit of a Veterans Affairs hospital.

The portable luminometer system was capable of detecting microbial and cellular contamination of flexible endoscopes following high-level disinfection and reprocessing. The sensitivity of the assay was sufficient for detecting low-level contamination.

The system provided a rapid microbiological outcome monitor for the cleaning and disinfection process. The system was easy to use and relatively accurate.

To describe an outbreak of serious nosocomial Burkholderia cepacia infections occurring after transrectal prostate biopsy associated with ultrasound gel intrinsically contaminated with paraben-degrading microorganisms.

A retrospective chart review prompted by a blood culture isolate of B, cepacia. Identification of microorganisms in ultrasound gel in two Canadian centers and characterization by pulsed-field gel electrophoresis and assays for paraben degradation.

Two Canadian university-affiliated, tertiary-care centers in Newfoundland and Alberta.

Six serious B. cepacia infections were identified at the two centers. Isolates of B. cepacia recovered from the blood of patients from both centers and the ultrasound gel used during the procedures were identical, confirming intrinsic contamination. Strains of Enterobacter cloacae isolated from ultrasound gel at the two centers were also identical. The ability to degrade parabens was proven for both B. cepacia and E. cloacae strains recovered from the ultrasound gel.

Ultrasound gel is a potential source of infection. Contamination occurs at the time of manufacture, with organisms that degrade parabens, which are commonly used as stabilizing agents. There are far-reaching implications for the infection control community.

Despite the novelties in operating room ventilation, airborne bacteria remain an important source of surgical wound contamination. An ultraclean airflow from the ceiling downward may convey airborne particles from the surgical team into the wound, thus increasing the risk of infection. Therefore, similar ventilation from the wound upward should be considered. We investigated the effect of wound ventilation on the concentration of airborne particles in a wound model during simulated surgery.

Randomized experimental study simulating surgery with a wound cavity model.

An operating room of a university hospital ventilated with ultraclean air directed downward.

Particles 5 um and larger were counted with and without a 5-cm deep cavity and with and with-out the insufflation of ultraclean air.

With the surgeon standing upright, no airborne particles could be detected in the wound model. In contrast, during simulated operations, the median number of particles per 0.1 cu ft reached 18 (25th and 75th percentiles, 12 and 22.25) in the model with a cavity and 15.5 (25th and 75th percentiles, 14 and 21.5) without. With a cavity, wound ventilation markedly reduced the median number of particles to 1 (range, 0 to 1.25; P< .001).

To protect a surgical wound against direct airborne contamination, air should be directed away from the wound rather than toward it. This study provides supportive evidence to earlier studies that operating room ventilation with ultraclean air is imperfect during surgical activity and that wound ventilation may be a simple complement. Further clinical trials are needed.

To assess compliance of anesthesiologist practices in antibiotic prophylaxis during total hip replacement (THR) surgery with the French Society of Anesthesiology and Intensive Care consensus-based guidelines.

Retrospective review of medical records. Compliance of anesthesiologist practices with the guidelines was assessed according to antibiotic prophylaxis use, antimicrobial agent, dosage of first injection, time from first dose to incision, and total duration of antibiotic prophylaxis.

Orthopedic surgery wards in a 2,200-bed French teaching hospital.

A random sample of 416 patients undergoing THR from January 1999 to December 2000.

Three hundred eighty-six (93%) of the sampled medical records were usable. Antibiotic prophylaxis was used for 366 (95%) of the patients. Total duration of prophylaxis did not exceed 48 hours in 98% (359 of 366) of the patients. Drug selection complied with national guidelines in 259 (71%) of the patients. Dosage and timing of the first injection were appropriate in 98% (290 of 296) and 80% (236 of 296) of the patients, respectively, who received one of the recommended antibiotics. Overall, 53% (203 of 386) of the patients met all five criteria. In multivariate analysis, there was a significant anesthesiologist effect on overall compliance with the guidelines (likelihood ratio chi-square with 9 degrees of freedom, 25.7; P < .01). Undergoing surgery during 2000 was the only patient characteristic associated with an increased rate of appropriate practices (adjusted OR, 1.56; CI95,1.02-2.38).

The overall compliance rate should be improved by disseminating the guidelines and the results of this study following audit and feedback.

To describe the development and implementation of a local protocol for antibiotic prophylaxis in surgery and to assess compliance with these guidelines using a computer-based system.

One 5-week prospective period (phase 1) followed by three 1-week, cross-sectional assessments (phases 2, 3, and 4).

Pharmacy of a 350-bed acute care teaching hospital in Barcelona, Spain.

In phase 1, 395 forms for antibiotic prescribing delivered to the pharmacy were reviewed. Nonadherence was defined as the prescription of an antibiotic (or doses) different from what the protocol specified. In phases 2, 3, and 4, antibiotic prescribing forms for all elective procedures (630 patients) performed during 1-week periods were analyzed.

A total of 1,047 patients (mean age, 58.9 ± 17.3 years) were included. Cefazolin was administered in 41% of procedures. Overall compliance with antibiotic prescribing forms was 83.3%. There was a statistically significant increase in compliance with guidelines throughout the four phases of the study, from 80.3% in phase 1 to 87.8% in phase 4 (P < .042), as well as adherence to completing forms for surgical procedures, from 51% in phase 2 to 77.6% in phase 4 (P < .001). The main reason for non-adherence was that some procedures had not been included in the protocol in phase 2.

Surgeons sensitized to the implementation of local antibiotic prophylaxis guidelines showed a high degree of compliance with them, using both the procedure established for antibiotic prescribing and the antimicrobials recommended for particular operations.

To investigate whether stratification of the risk of developing a surgical-site infection (SSI) is improved when a logistic regression model is used to weight the risk factors for each procedure category individually instead of the modified NNIS System risk index.

The German Nosocomial Infection Surveillance System, based on NNIS System methodology, has 273 acute care surgical departments participating voluntarily. Data on 9 procedure categories were included (214,271 operations).

For each of the procedure categories, the significant risk factors from the available data (NNIS System risk index variables of ASA score, wound class, duration of operation, and endoscope use, as well as gender and age) were identified by multiple logistic regression analyses with stepwise variable selection. The area under the receiver operating characteristic (ROC) curve resulting from these analyses was used to evaluate the predictive power of logistic regression models.

For most procedures, at least two of the three variables contributing to the NNIS System risk index were shown to be independent risk factors (appendectomy, knee arthroscopy, cholecystectomy, colon surgery, herniorrhaphy, hip prosthesis, knee prosthesis, and vascular surgery). The predictive power of logistic regression models (including age and gender, when appropriate) was low (between 0.55 and 0.71) and for most procedures only slightly better than that of the NNIS System risk index.

Without the inclusion of additional procedure-specific variables, logistic regression models do not improve the comparison of SSI rates from various hospitals.

To determine the frequency and type of nosocomial infections (NIs) (especially surgical-site infections [SSIs]), risk factors, and the type and duration of antibiotic use among surgical patients in Greek hospitals.

Two point-prevalence studies.

Fourteen Greek hospitals.

Those in the hospitals during two prevalence surveys undergoing surgery during their stay.

In the 1999 survey, 129 of 1,037 surgical patients had developed 148 NIs (14.3%). A total of 1,093 operations were registered, and 49 SSIs (4.5%) were found. In the 2000 survey, 82 of 868 surgical patients had developed 88 NIs (10.1%). A total of 902 operations were registered, and 38 SSIs were detected (4.2%). The median length of stay (LOS) for surgical patients without SSI was 10.0 days (range, 1-19 days); for patients who developed SSI it was 30 days (range, 1-52 days; P < .001). The median LOS prior to surgery for patients without SSI was 1 day (range, 0-4 days); for patients who developed SSI it was 3 days (range, 0-7.5 days; P < .001). Among 30 possible risk factors studied, wound class, LOS prior to surgery, and central venous catheterization were independent predictors of SSI. Median durations of prophylactic antibiotic therapy were 4 days (range, 1-14 days) and 6 days (range, 1-16 days) in the 1999 and 2000 surveys, respectively.

Surgical patients in Greek hospitals suffered higher rates of SSI than did surgical patients in other developed countries while prophylactic antibiotics were used excessively.

Rapid identification and investigation of potential outbreaks is key to limiting transmission in the healthcare setting. Manual review of laboratory results remains a cumbersome, time-consuming task for infection control practitioners (ICPs). Computer-automated techniques have shown promise for improving the efficiency and accuracy of surveillance. We examined the use of automated control charts, provided by an automated surveillance system, for detection of potential outbreaks.

A 656-bed academic medical center.

We retrospectively reviewed 13 months (November 2001 through November 2002) of laboratory-patient data, comparing an automated surveillance application with standard infection control practices. We evaluated positive predictive value, sensitivity, and time required to investigate the alerts. An ICP created 75 control charts. A standardized case investigation form was developed to evaluate each alert for the likelihood of nosocomial transmission based on temporal and spatial overlap and culture results.

The 75 control charts were created in 75 minutes and 18 alerts fired above the 3-sigma level. These were independently reviewed by an ICP and associate hospital epidemiologist. The review process required an average of 20 minutes per alert and the kappa score between the reviewers was 0.82. Eleven of the 18 alerts were determined to be potential outbreaks, yielding a positive predictive value of 0.61. Routine surveillance identified 5 of these 11 alerts during this time period.

Automated surveillance with user-definable control charts for cluster identification was more sensitive than routine methods and is capable of operating with high specificity and positive predictive value in a time-efficient manner.