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 an increase in the number of Salmonella enteritidis isolates detected in a large hospital to ascertain whether it was due to a nosocomial source, to identify the mechanisms of transmission, and to institute effective control measures to prevent future episodes.

Observational study, survey of all microbiological samples positive for S. enteritidis detected in the hospital, outbreak investigation, and review of the literature.

A tertiary-care teaching hospital for adults in Barcelona, Spain.

During a 7-month period from May to November 1998, we identified 22 inpatients with S. enteritidis infection for whom nosocomial acquisition was strongly suspected. The attack rate was 0.138 per 1,000 patient-days. All affected patients were immunosuppressed and overall mortality was 41% (9 of 22). A sample of a meal cooked in the kitchen was culture positive for S. enteritidis. All isolates shared the same antibiotic susceptibility pattern and all except one shared the same pulsed-field gel electrophoresis (PFGE) pattern, but PFGE could not differentiate between outbreak-related and control strains. After compliance with kitchen hygiene procedures was emphasized and cleansing was intensified, no more cases were detected.

Apparently, sporadic cases of S. enteritidis may be part of an outbreak with a low attack rate. A small but persistent inoculum affecting only individuals with special predisposition for Salmonella infection might account for this. Suspicion should be raised in hospitals and institutions with a highly susceptible population.

To evaluate intrahospital and interhospital clonal dissemination of extended-spectrum beta-lactamase (ESBL)-producing strains of Klebsiella pneumoniae.

Eight tertiary-care university hospitals and 16 regional hospitals in Taiwan.

Two hundred eleven confirmed ESBL-producing isolates of K. pneumoniae were collected from January 1998 to June 2000. The isolates were characterized by various typing methods, including antibiogram (9 antimicrobial agents), computer-based ribotyping, pulsed-field gel electrophoresis (PFGE), and isoelectric focusing of beta-lactamase.

Ribotyping identified 70 distinct ribogroups among 200 isolates evaluated. Forty-three of these ribogroups were unique. Eleven ribogroups, comprising 115 isolates, were detected in more than one hospital (interhospital dissemination), whereas 16 groups (42 isolates) were detected in more than one patient within a hospital (intrahospital dissemination). The combination of ribotyping and PFGE identified two large epidemic clones, which were called 691.5/PFGE-G and 595.7/PFGE-A. These epidemic clones were detected mainly in the hospitals located in the northern and central regions of Taiwan. However, variation of the profiles of antibiograms and isoelectric focusing was apparent within each clone. In addition, isolates with the same isoelectric focusing profile (isoelectric points 7.9, 8.2, and 8.4) and antibiogram (resistance to 9 compounds evaluated) were present among different molecular-typed clones.

Our results showed that clonal dissemination (both interhospital and intrahospital dissemination) is occurring in several regions of Taiwan. Rapid computer-based ribotyping associated with PFGE demonstrated multiple epidemic clones of ESBL-producing K. pneumoniae in Taiwan. The combination of phenotypic and molecular methods has proved useful to characterize these epidemic clones.

To assess the effect of implementing safety-engineered devices on percutaneous injury epidemiology, specifically on percutaneous injuries associated with a higher risk of blood-borne pathogen exposure.

Before-and-after intervention trial comparing 3-year preintervention (1998–2000) and 1-year postintervention (2001–2002) periods. Percutaneous injury data have been entered prospectively into CDC NaSH software since 1998.

A 427-bed, tertiary-care hospital in Manhattan.

All employees who reported percutaneous injuries during the study period.

A “safer-needle system,” composed of a variety of safety-engineered devices to allow for needle-safe IV delivery, blood collection, IV insertion, and intramuscular and subcutaneous injection, was implemented in February 2001.

The mean annual incidence of percutaneous injuries decreased from 34.08 per 1,000 full-time–equivalent employees preintervention to 14.25 postintervention (P < .001). Reductions in the average monthly number of percutaneous injuries resulting from both low-risk (P < .01) and high-risk (P was not significant) activities were observed. Nurses experienced the greatest decrease (74.5%, P < .001), followed by ancillary staff (61.5%, P = .03). Significant rate reductions were observed for the following activities: manipulating patients or sharps (83.5%, P < .001), collisions or contact with sharps (73.0%, P = .01), disposal-related injuries (21.41%, P = .001), and catheter insertions (88.2%, P < .001). Injury rates involving hollow-bore needles also decreased (70.6%, P < .001).

The implementation of safety-engineered devices reduced percutaneous injury rates across occupations, activities, times of injury, and devices. Moreover, intervention impact was observed when stratified by risk for blood-borne pathogen transmission.

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 assess changes in the epidemiology of nosocomial candidemia in the post-fluconazole era among hospitalized patients using a case–control study design.

Candidemia case-patients were matched 1:1 on diagnosis, age, and length of stay with control-patients. Conditional logistic regression was used to determine predictors and outcomes of candidemia. Treatment regimens and compliance with national practice guidelines were compared among case-patients.

Barnes-Jewish Hospital, a 1,278-bed, tertiary-care center affiliated with Washington University School of Medicine, St. Louis, Missouri.

Patients admitted from January 1 to December 31, 2000. Case-patients were identified through the hospital microbiological surveillance system and matched with control-patients.

Predictors of candidemia included Hickman catheters (odds ratio [OR], 9.53; 95% confidence interval [CI95], 1.34 to 68.01), gastric acid suppressants (OR, 6.38; CI95, 2.33 to 17.43), nasogastric tubes (OR, 3.69; CI95, 1.27 to 10.78), antibiotics (OR, 1.46; CI95,1.15 to 1.86), and admission to the intensive care unit (OR, 6.40; CI95, 2.12 to 19.31). The crude case-fatality rate was 40%. Seventeen (15%) of the case-patients received the recommended treatment regimen according to recently published practice guidelines.

The epidemiology of candidemia has changed little at our hospital during the past decade and remains a significant cause of mortality. Further studies on the benefits of preventive therapy will be essential to improve the outcome of this infection.

Serratia marcescens can cause serious infections in patients in neonatal intensive care units (NICUs), including sepsis, pneumonia, urinary tract infection, and conjunctivitis. We report the utility of genetic fingerprinting to identify, investigate, and control two distinct outbreaks of S. marcescens.

An epidemiologic investigation was performed to control two clusters of S. marcescens infections and to determine possible routes of transmission. Molecular typing by pulsed-field gel electrophoresis determined the relatedness of S. marcescens strains recovered from neonates, the environment, and the hands of healthcare workers (HCWs).

Two geographically distinct level III-IV NICUs (NICU A and NICU B) in two university-affiliated teaching hospitals in New York City.

In NICU A, one major clone, “F,” was detected among isolates recovered from four neonates and the hands of one HCW. A second predominant clone, “A,” was recovered from four sink drains and one rectal surveillance culture from an asymptomatic neonate. In NICU B, four neonates were infected with clone “D,” and three sink drains harbored clone “H.” The attributable mortality rate from bloodstream infections was 60% (3 of 5 infants). The antimicrobial susceptibilities of clone F strains varied for amikacin, cefepime, and piperacillin/tazobactam.

S. marcescens causes significant morbidity and mortality in preterm neonates. Cross-transmission via transient hand carriage of a HCW appeared to be the probable route of transmission in NICU A. Sinks did not harbor the outbreak strains. Antimicrobial susceptibility patterns did not prove to be an accurate predictor of strain relatedness for S. marcescens.

To determine the occurrence of co-colonization or co-infection with VRE and MRSA among medical patients requiring intensive care.

Prospective, single-center, observational study.

A 19-bed medical ICU in an urban teaching hospital.

Adult patients requiring at least 48 hours of intensive care and having at least one culture performed for microbiologie evaluation.

Eight hundred seventy-eight consecutive patients were evaluated. Of these patients, 402 (45.8%) did not have microbiologie evidence of colonization or infection with either VRE or MRSA 355 (40.4%) were colonized or infected with VRE, 38 (4.3%) were colonized or infected with MRSA, and 83 (9.5%) had co-colonization or co-infection with VRE and MRSA. Multiple logistic regression analysis demonstrated that increasing age, hospitalization during the preceding 6 months, and admission to a long-term-care facility were independently associated with colonization or infection due to VRE and co-colonization or co-infection with VRE and MRSA. The distributions of positive culture sites for VRE (stool, 86.7%; blood, 6.5%; urine, 4.8%; soft tissue or wound, 2.0%) and for MRSA (respiratory secretions, 34.1%; blood, 32.6%; urine, 17.1%; soft tissue or wound, 16.2%) were statistically different (P < .001).

Co-colonization or co-infection with VRE and MRSA is common among medical patients requiring intensive care. The recent emergence of vancomycin-resistant Staphylococcus aureus and the presence of a patient population co-colonized or co-infected with VRE and MRSA support the need for aggressive infection control measures in the ICU.