To describe the investigation of a pseudo-outbreak of multiresistant Pseudomonas aeruginosa fecal colonization in a hematology unit.

Retrospective chart review; prospective environmental sampling and observation of stool culture technique; genotyping by random arbitrary primer polymorphic DNA polymerase chain reaction (RAPD-PCR).

An academic tertiary-care hospital.

Between August and October 1994, P aeruginosa resistant to imipenem, ceftazidime, ciprofloxacin, and all aminoglycosides was isolated from surveillance stool cultures from 10 neutropenic patients cared for in the hematology unit. P aeruginosa, with an identical susceptibility pattern, was isolated from three patients admitted to the same unit in the year before the “outbreak.” Two months before the outbreak, 12 healthcare workers had been added to the staff.

Observation of stool sampling techniques as performed by healthcare workers revealed that samples for surveillance cultures were taken from feces in the toilet. When the proper sampling technique was used, P aeruginosa was not isolated from stool samples from 8 of 10 patients with previously positive cultures. P aeruginosa also was isolated from two wash basins, toilet flushing water, and a toilet brush. Genotyping by RAPD-PCR showed that the isolate from the toilet flushing water was identical to the P aeruginosa strains of eight patients from the outbreak.

This pseudo-outbreak emphasizes the importance of proper sampling techniques and that periodic observation may be necessary to verify proper sampling techniques.

To describe the derivation and validation of a pulmonary tuberculosis (TB) prediction model that would enable early discontinuation of unnecessary respiratory isolation.

Patients placed in isolation for suspected pulmonary TB were studied retrospectively (derivation cohort) and prospectively (validation cohort). Independent predictors of pulmonary TB in the derivation cohort (January 1992-March 1994) were identified by retrospective analysis. Predictors in the model were assigned weights on the basis of the results of the multivariate analysis in order to quantitate the risk of TB in an individual patient. The prospective validation consisted of application of the model to patients placed in isolation during the period April 1994 to June 1995. The predictability of the model in the derivation and validation cohorts was evaluated using receiver operating characteristics (ROC), curve analysis, and calculation of the area under the ROC curve (AUC).

A university-affiliated, urban, public hospital with a large population of prison inmates and patients with human immunodeficiency virus infection.

Prospective application of the prediction model to patients placed in isolation during the validation period.

Four factors were found to be independent predictors of pulmonary TB among 296 isolation episodes in the derivation cohort: positive acid-fast sputum smear (odds ratio [OR], 5.8; 95% confidence interval [CI95], 3.0-11.0; weight=3 points), localized chest radiograph findings (OR, 2.5; CI95,1.3-4.9; weight=2 points), residence in a correctional facility (OR, 2.3; CI95, 1.2-4.4; weight=2 points), and history of weight loss (OR, 1.8; CI95, 1.0-3.2; weight=1 point). Infection control practitioners applied the model prospectively to 220 isolation episodes. The mean (土SE) AUCs of the ROC curve for the derivation and validation cohorts were not significantly different (.86±.04 vs.86±.07; P=.90). There was a significant decline in the mean duration of isolation from the onset of an automatic TB isolation policy in August 1992 to the end of the study (P=.045 by analysis of variance).

A pulmonary TB prediction model was derived and validated prospectively in a hospital with a moderately high prevalence of TB. The model quantitated the risk of TB in an individual patient and aided infection control practitioners and primary-care physicians in their decisions to discontinue isolation during the validation period. Utilization of the model was responsible, in part, for a decrease in the mean duration of isolation during the study period. Although the model may not have general applicability due to the uniqueness of the patient population studied, this study illustrates how prediction models can be developed and used effectively to deal with a clinical problem.

To study the cost-effectiveness of vaccination for hepatitis A.

Hypothetical analysis of students currently enrolled in medical school in the United States.

A Markov-based model was developed using data from the literature, actual hospital costs, and an annual discount rate of 5%. The incidence rate was based on the lowest annual rate for the US population during the past decade.

Over the lifetimes of students currently in medical school, the model estimated that there would be 286 hepatitis A cases with four deaths and 107 lost years of life. With routine vaccination, these numbers would decrease to 17, 0.3, and 6, respectively. The costs per life-year saved and quality adjusted life-year saved were $58,000 and $47,000, respectively. Serologic screening prior to vaccination was less cost-effective than universal vaccination. If the incidence of hepatitis A was underestimated by a factor of 5, the cost per life-year saved would decrease to $5,500. If the incidence of hepatitis was underestimated by a factor of 10, vaccination would result in a net cost savings.

We conclude that the cost per life-year saved by routine hepatitis A vaccination was similar to many other standard medical modalities. For routine vaccination of medical students to be cost-saving, the incidence rate for hepatitis A must be at least 10 times higher than the rate presently reported for the general population. Serological screening prior to vaccination was not cost-effective.

To study the compliance, and reasons for noncompliance, with Universal Precautions and the associated circumstances of mucocutaneous blood exposure (MCE) among Danish physicians.

A nationwide questionnaire survey.

All Danish hospitals.

All hospital-employed physicians.

Of 9,384 questionnaires, 6,256 (67%) were returned, and 6,005 were eligible for analysis. Only 35% of respondents were compliant with the basic principle of Universal Precautions. Compliance with specific barriers in the preceding week among “surgeons and pathologists” and “other physicians” was as follows: gloves, 63.0% and 23.4%; masks, 55.2% and 17.6%; and protective eyewear, 11.5% and 4.0%, respectively. Common arguments for non-compliance were “interferes with working skills,” “forget,” “wear spectacles,” “not available,” “too much trouble to get,” or “gloves do not fit.”

Detailed descriptions of 741 MCEs were obtained. Blood splashes in the eyes (n=320) was the most common MCE in surgical specialties and pathology, whereas blood on the hands (n=290) was most common in other specialties. In 20% of MCEs of the eyes, the exposure occurred despite the use of spectacles. An estimated 84% to 98% of MCEs potentially would have been preventable had appropriate barriers been worn. More than one half of MCEs were preventable by two interventions only: compulsory use of protective eyewear during operations and use of gloves during insertion of peripheral intravenous catheters.

Compliance with Universal Precautions is unacceptably low, as reflected by the circumstances of MCE. Increased efforts to ensure education in Universal Precautions, easy accessibility of protective barriers, and improved design of the barriers are necessary to improve compliance and reduce the risk of MCE.

Assess the effect and use of resources associated with implementation of a program for the systematic follow-up of positive blood cultures.

Prospective epidemiologic study.

Tertiary-care military medical center.

All positive blood cultures (BC) were reported via E-mail to an infectious disease specialist as soon as growth was noted. This individual reviewed all Gram stains, clinical data, and antibiotic information on these patients.

From June 26, 1994, through January 25, 1995, there were 3,121 BCs drawn, of which 199 (6.4%) were positive from 145 episodes. Sixty-three episodes involved probable contaminants, and 82 episodes were considered true bacteremias. Six patients with true bacteremia died, two were transferred, and three were discharged within 24 hours of drawing the positive BC. Of the remaining 71 true bacteremias, 9 patients were on inadequate empiric therapy, as judged by the final organism susceptibilities. Changes in empiric therapy were recommended for five of the nine episodes and were implemented by the primary physicians in each case. Each of the changes resulted in improved coverage (as judged by the final identification and susceptibilities).

This program has improved the quality of care at Keesler Medical Center at the cost of one additional hour of consultant time per week.

To characterize and enumerate central venous catheter (CVC)-related complications among children with chronic illnesses, and to reduce the complication rate through changes in CVC management and education.

A prospective obser vational study followed by an educational program and a nonrandomized inter ventional trial.

The Children's Hospital of Philadelphia, a tertiary, pediatric facility.

268 children with Broviac, Hickman, or Infusaport catheters in place during 58,290 catheter days.

Development and implementation of protocols for cleaning insertion site and hub, use of nonocclusive dressings, and manipulation of access; formal staff and parental education about protocols.

CVC-related infections fell from 4.58/1,000 catheter-days preinter vention to 3.83 postintervention (risk ratio [RR], 0.20; 95% confidence interval [CI95], 0.89-1.622; P=.25); exit-site infections fell from 0.58 to 0.11 (CI95, 1.22-45.64; P=.02); rates among infants on the surgical service fell from 15.46 to 6.67 (RR, 2.31; CI95, 1.10-4.30; P=.02).

Education and changes in management protocols reduced the incidence of exit-site infections among all patients and reduced the overall infectious complication rate among the infants receiving parenteral nutrition on the surgical ser vice. Other interventions are needed to decrease further the infectious complications in these children