To report the contamination of ventilator equipment with Bacillus cereus and to outline the measures taken to trace the source of the organism.

A prospective survey of all intensive care unit patients who were culture-positive for B cereus and obtaining of environmental cultures of the cleaning and assembly area of the respiratory services division between October 1991 and September 1992.

Ventilated patients from a 16-bed medical and surgical intensive care unit (ICU) in a 1,000-bed adult tertiary care hospital.

From October 1991 to April 1992, B cereus colonized the ventilator circuitry of patients in the ICU. One of two washer/decontaminators in the cleaning and assembly area of the respiratory services division was found to yield the microorganism consistently from the water intake port. The design of the machine precluded easy decontamination of the port with 2% gluteraldehyde and a second outbreak occurred. Following the second outbreak, aqueous chlorhexidine in a final concentration of 0.05% was added to the first of two pasteurization cycles in an attempt to achieve sporicidal activity. This ended the outbreak. Sixty-two patients became colonized with the organism including two with nonfatal Bacillus sepsis and one death due to pneumonia associated with the organism.

This experience emphasizes the importance of obtaining cultures of machine parts to identify the source of contamination and thereby direct control measures. Use of chlor-hexidine gluconate at high temperatures effectively eradicated B cereus from ventilator circuitry in a practical and cost-effective manner.

Multipatient use and prolonged use of prefilled disposable oxygen humidifier bottles (Aquapak 301, Respiratory Care, Inc., Arlington Heights, IL) were evaluated by performing microbiologic monitoring and a cost analysis on bottles used for varying numbers of patients and lengths of time.

Humidifiers were hung for a maximum of one month. Monitoring was conducted in 6 different nursing areas. Quantitative cultures were done for aerobes and Legionella. Reusable humidifier bottles also were monitored.

Cultures were obtained from 1,311 disposable and 60 reusable humidifiers. No significant bacterial contamination was detected in the prefilled disposable oxygen humidifier units. Ten percent of the reusable bottles were contaminated by organisms associated with skin flora.

Multipatient use and increased duration of use of disposable humidifiers result in cost savings without increasing patient risk. Restricted multipatient use of prefilled disposable oxygen humidifier bottles for a period of one month is a safe and cost-efficient practice.

To identify risk factors for sepsis following urinary extracorporeal shock wave lithotripsy (ESWL).

Retrospective case-control study with two control groups.

A rural, 570-bed, regional referral center.

Six cases (four bacteremias and two fungemias) were compared with two sets of 18 controls. Cases had a higher frequency and number of urinary tract infections prior to the procedure and tended to have larger stone size.

Patients undergoing ESWL who are at high risk for infectious complications may be identified by preprocedure evaluation. Such patients may require alternative prophylactic regimens and close postprocedure follow-up.

To test the hypothesis that multiple needlestick injuries in hospital employees may he due to intrinsic deficits in hand dexterity.

A case-control study comparing employees with multiple reported needlestick injuries to those with none. Hand dexterity was tested using the Purdue Pegboard Test, a standardized validated test of hand dexterity.

A 300-bed, acute care teaching hospital.

Fifteen hospital employees who sustained four or more injuries were compared to 19 controls.

No differences were detected in hand dexterity between the case and control groups.

While employees with multiple needlestick injuries accounted for 85% of reported injuries, underlying factors responsible for injuries in this high-risk subgroup do not include measurable deficits in hand dexterity.

To evaluate the efficacy of giving a third dose of recombinant hepatitis B vaccine to healthcare workers who already had received two doses of serum-derived vaccine, which is no longer available in the United States.

Volunteers who already had received two standard doses of serum-derived vaccine were given a third dose of either serum or recombinant vaccine in a double-blind fashion. Antibodies to hepatitis B surface antigen were measured at the time of the third immunization, three months later, and one year after the third immunization.

U.S. Army Medical Center, El Paso, Texas.

One hundred healthy healthcare workers.

Three months after receiving the third immunization, the serum vaccine group had significantly higher titers than the recombinant vaccine group (P= 0.018). One year after receiving the third immunization, those who received the combined regimen had a mean hepatitis B surface antibody titer less than half that of those who received three doses of serum-derived vaccine. However, both regimens resulted in titers that are considered to confer immunity.

A regimen that combines serum and recombinant hepatitis B vaccines may not produce as high an antibody level as three doses of the same vaccine. Those who began immunization with serum vaccine and concluded with recombinant vaccine should be monitored for an accelerated drop in serum antibodies.