To develop a method to evaluate directional airflow patterns, air dilution, and air mixing in facilities where tuberculosis patients are seen.

A tuberculosis patient isolation room was evaluated by analyzing pressure differential between the room and the corridor and by using theatrical fog to visualize room air movement and impact of dilution and exchange, as well as air capture and displacement. Tracer gas was compared to fog results and used to calculate air exchange rates.

A small research hospital.

By adding theatrical fog to the patient room at several locations, we quickly learned that most of the air entering the room through the transom and around the door to the corridor was exhausted through the three exhaust vents. Little air appeared to move toward the exhaust fan.

For comparison and to confirm the room air exchange rate, tracer gas was distributed and sampled. The kinetics of decay were very similar whether the tracer gas and room air were mixed during sampling or not.

The fog procedure allowed good visual confirmation of air mixing and airflow patterns and provided quantitative data for evaluating the efficacy of air capture and displacement or dilution and exchange

To measure the prevalence of, and to establish predictors for, the nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) at hospital admission. To evaluate mannitol-salt agar with oxacillin for the simultaneous detection and identification of MRSA from nasal swabs.

Three-month prospective case-control survey, with data collected from interviews and computerized databases. The criterion standard for MRSA detection was culture on Mueller-Hinton agar with oxacillin 6 μg/mL (National Committee for Clinical Laboratory Standards method).

320-bed tertiary-care hospital.

387 patients screened within 24 hours after admission, including 10 MRSA carriers (cases), 291 patients with no S aureus, and 86 patients with methicillin-susceptible S aureus.

The prevalence of MRSA nasal carriage was 2.6%, whereas the prevalence of carriage was 3.1% when both nasal and wound cultures were performed. The significant predictors of carriage were a prior detection of MRSA, open wounds, diabetes mellitus, treatments by injection, prior nursing home stays, visits at home by a nurse, and prior antibiotic treatments. Cases had stayed for longer periods in hospitals and had received longer antibiotic treatments within a year. Eighty patients (including the 10 cases) had diabetes, had been exposed to healthcare facilities within a year, and had antibiotics within 6 months. The sensitivity and negative predictive value of nasal swabs on mannitol-salt agar with oxacillin were 60% and 71%, respectively.

MRSA carriage on admission to the hospital may be an increasing and underestimated problem. Further studies are needed to develop and validate a sensitive and specific prediction rule.

To reduce the use of amoxicillin-clavulanate after high-resistance rates in Escherichia coli were detected.

Intervention study; the interventions were introduced successively over a 4-year period while closely monitoring the resistance patterns.

A 260-bed acute-care hospital in Switzerland.

Introduction of therapeutic guidelines for specific departments or indications, which proposed alternative antibiotics to amoxicillin-clavulanate. The perioperative prophylactic use of amoxicillin-clavulanate was eliminated completely.

The absolute amount of amoxicillin-clavulanate consumed decreased by 23%, from 24.8 g per 100 patient days in 1992 to 18.5 g per 100 patient days in 1995. The number of courses, a parameter that takes the prophylactic use into account, decreased by 62% from 2.3 per 100 patient days in 1992 to 0.9 per 100 patient days in 1995. The percentage of sensitive strains increased from 54.9% (n=512) in 1992 and 54.0% (n=506) in 1993 to 72.1% (n=546) in 1994 and 83.1% (n=668) in 1995. No major changes were detected for other antimicrobials, such as cotrimoxazole, tetracycline, or cefuroxime, used in this 4-year period.

A decrease in the use of amoxicillin-clavulanate was followed by an increase in susceptibility of E coli to it. It was not possible to prove a causative relationship. Only a temporal association was discovered. The reduction of the use of amoxicillin-clavulanate was achieved through the implementation of treatment guidelines, facilitated through a close collaboration among the clinical pharmacists, the infection control practitioner, the microbiology laboratory, and the physicians in charge of the respective departments.

To investigate differences in second-, third-, and fourth-year medical students' knowledge of bloodborne pathogen exposure risks, as well as their attitudes toward, and intentions to comply with, Universal Precautions (UP).

Cross-sectional survey.

Surveys about students' knowledge, attitudes, and intentions to comply with UP were completed by 111 second-year (preclinical), 80 third-year, and 60 fourth-year medical students at Washington University School of Medicine in the spring of 1996.

Preclinical students knew more than clinical students about the efficacy of hepatitis B vaccine, use of antiretroviral therapy after occupational exposure to human immunodeficiency virus, and nonvaccinated healthcare workers' risk of infection from needlestick injuries (P<.001). Students' perceived risk of occupational exposure to bloodborne pathogens and attitudes toward hepatitis B vaccine did not differ, but preclinical students agreed more strongly that they should double glove for all invasive procedures with sharps (P<.001). Clinical students agreed more strongly with reporting only high-risk needlestick injuries (P = .057) and with rationalizations against using UP (P = .008). Preclinical students more frequently reported contemplating or preparing to comply with double gloving, wearing protective eyewear, reporting all exposures, and safely disposing of sharps, whereas students with clinical experience were more likely to report compliance. Clinical students also were more likely to report having “no plans” to practice the first three of these precautions (P<.001).

Differences in knowledge, attitudes, and intentions to comply with UP between students with and without clinical experience may have important implications for the timing and content of interventions designed to improve compliance with UP.

To assess baseline health status of a medical school employee population and to assess this population's acceptance of vaccination and other interventions to reduce risk of disease transmission.

A retrospective review of an employee health records database for a 4-year period.

A large, urban university hospital.

5,007 employees screened by employee health for immunity to vaccine-preventable illnesses and tuberculosis.

9.4% of the employees had positive tuberculin skin tests, with a conversion rate of 6.4% for those who had negative tests within the previous 2 years. Two individuals were identified who had active pulmonary tuberculosis. Fewer than 10% of the individuals for whom isoniazid chemoprophylaxis was recommended completed the 6 months of therapy. Most clinical employees (96.1%) did not have a history of prior hepatitis B virus (HBV) infection or immunization, but 77% of them subsequently completed the vaccination series. Most employees with a negative history for infection with or immunization against rubella, rubeola, and varicella had serological evidence of immunity (90.2%, 97.9%, and 87.2%, respectively).

Review of aggregate employee health databases may assist individuals who must establish strategies for prevention of occupational illness and disease transmission in this specialized setting. While many employees at risk for HBV complete the vaccination series, strategies for improving this rate could be helpful. Substantial work is needed to analyze reasons why so few individuals for whom isoniazid chemoprophylaxis is recommended complete the therapy, and strategies tailored to the impediments identified should be implemented.