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.

To compare a surveillance definition of nosocomial bloodstream infections requiring only microbiology data to the Centers for Disease Control and Prevention's (CDC) current definition.

Six teaching hospitals.

We classified a representative sample of 73 positive blood cultures from six hospitals growing common skin contaminant isolates using a definition for bacteremia requiring only microbiology data and the CDC definition for primary bloodstream infection (National Nosocomial Infections Surveillance [NNIS] System review method). The classifications assigned during routine prospective surveillance also were noted, and the time required to classify isolates by the two methods was compared.

Among 65 blood cultures growing common skin contaminant isolates obtained from adults, the agreement rate between the microbiology data method and the NNIS review method was 91%. Agreement was significantly poorer for the eight blood cultures growing common skin contaminant isolates obtained from pediatric patients. The microbiology data method requires approximately 20 minutes less time per isolate than does routine surveillance.

A definition based on microbiology data alone yields the same result as the CDC's definition in the large majority of instances. It is more resource-efficient than the CDC's current definition

To evaluate the distribution of Bordetella pertussis and respiratory syncytial virus (RSV) in the hospital setting.

Air samples were collected using filters in the hospital rooms of 12 children with pertussis and 27 children with RSV infection. Material eluted from these filters was subjected to RSV- and B pertussis-specific polymerase chain reaction (PCR) amplification.

Patients were hospitalized in private rooms in one of two referral centers, a university teaching hospital and a university-affiliated private children's hospital.

12 children (16 days-3 years of age) with documented pertussis infection and 27 patients (10 days-7 years of age) with documented RSV infection.

B pertussis DNA was detected in 7 (58%) of 12 rooms housing pertussis patients and in 16 (25%) of 63 total samples. B pertussis DNA was detected as far as 4 m away from the patient's bedside. The detection of B pertussis DNA in air samples did not change over the short duration of hospitalization. RSV RNA was detected in 17 (63%) of 27 rooms housing RSV-infected patients and in 32 (22%) of 143 total samples. RSV RNA was detected at distances as far as 7 m from the patient's bedside and for up to 7 days of hospitalization.

Using PCR-based detection methods, B pertussis DNA and RSV RNA both can be detected in air samples from the hospital rooms of infected patients. Both can be detected at large distances from a patient's bedside in a minority of cases. These detection methods are suitable for further studies of control measures used to contain nosocomial infections caused by both B pertussis and RSV.

To determine risk factors for an increase in line-associated bloodstream infections (BSIs) in three pediatric intensive-care units at one hospital that recently had changed brands of needleless access device.

Retrospective case-control studies; review of the units' infection control policies and procedures for accessing and replacing components of needleless access devices.

A community tertiary-care hospital's three pediatric intensive-care units.

Children in one of the three intensive-care units with a central venous catheter in place during January 1, 1995, through May 15, 1996, who developed laboratory-confirmed primary BSI. Children who had central venous catheters in place for >48 hours and who did not develop BSI were chosen randomly as controls.

Eight patients met the case definition; they had 11 episodes of BSI. Multivariate analysis identified duration of catheterization and exposure to the IVAC first-generation needleless device as independent risk factors for BSI. Compared with patients from another pediatric intensive-care unit in which the IVAC device also was used but in which an increased BSI rate did not occur, patients from the unit with an increased BSI rate were more likely to receive intermittent (vs continuous) intravenous therapy through one or more lumens. In both units, the IVAC device valve component was replaced every 6 days, and the endcap used to cover the valve (when connected to an unused lumen) was replaced every 24 hours or after each access. The BSI rate returned to baseline after institution of a policy to replace the entire IVAC device, valve, and endcap every 24 hours.

An increased risk of BSI was associated with use of the IVAC first-generation needleless device when replaced every 6 days. This increased risk may have been more pronounced in one pediatric intensive-care unit, because patients were more likely to receive intermittent intravenous therapy. Intermittent intravenous therapy or central venous catheter flushing practices may be important determinants of BSI risk

To investigate possible cross-contamination of laboratory specimens, as suggested by an increased incidence of newly diagnosed patients with tuberculosis, many of whom had all negative smears for acid-fast bacilli and only one positive Mycobacterium tuberculosis culture referred to as “negative smears, one positive“ or NSOP.

Medical-record reviews were performed for all patients with NSOP results diagnosed at this facility within a 9-month period. Laboratory logbooks were reviewed for all isolates processed; DNA fingerprinting was performed on available isolates.

Of 80 patients with NSOP results, 45 (56%) were found to have false-positive cultures resulting from laboratory contamination with H37Ra, an avirulent stock strain of Mycobacterium tuberculosis.

Laboratory cross-contamination resulted in the false diagnosis of tuberculosis in at least 45 individuals. Use of the Mycobacteria Growth Indicator Tube may have contributed to these contamination incidents by detecting small numbers of contaminating mycobacteria that may not have been detected with less sensitive media.