To determine the ability of a commercially available biological indicator (BI), used to monitor steam and ethylene oxide sterilization, to biologically monitor a liquid sterilization process consisting of a sterile processor, a proprietary peracetic acid sterilant, and a sterile rinse system.

Analysis of spore survival in BIs tested in STERIS SYSTEM 1™ liquid chemical sterilization processor and in vitro.

STERIS Corp. research laboratory.

In vitro tests were performed in the STERIS SYSTEM 1 Processor using 12-minute and 6-minute sterilant exposure cycles. D values (time to inactivate one log of spores), spore washoff and outgrowth time, and inhibitory effects of the sterilant were determined.

Sterilization of the spore-inoculated filter paper strips in the BIs was ascertained in both processor testing and in vitro tests using conditions identical to those in the processor. The extensive washing and dilution during the processor cycle resulted in only 0.2% and 1.8% removal of the spores from Bacillus stearother-mophilus and Bacillus subtilis inoculated spore strips, respectively.

Carryover of the diluted sterilant to the culture medium did not inhibit the outgrowth of the spores, and D values could be obtained. B Stearothermophilus was two to three times more resistant to the sterilant than B subtilis. However, either spore meets the performance specifications applicable to BIs for monitoring sterilization processes.

The data demonstrate that the commercial Bis evaluated are reproducible and verifiable indicators of the liquid chemical sterilization process. The same kind of performance specifications for producing BIs used to monitor steam or ethylene oxide systems also apply to the evaluated liquid chemical sterilization system.

Identification of overall and site-specific rates of nosocomial infection in neutropenic patients with cancer and associated pathogens.

Cumulative continuous prospective surveillance over a 42-month period. Criteria and definitions of infection in neutropenic patients (absolute neutrophil counts < 1,000/mm3) were developed, and surveillance was carried out by a certified infection control nurse and a senior oncology research fellow.

A cancer research center with two designated oncology nursing units.

Neutropenic patients with hematological and solid malignancies undergoing high-dose chemotherapy with and without autologous bone marrow transplantation. All patients admitted to both of the units during the study period were surveyed. Those who developed neutropenia are included in this report.

A total of 444 nosocomial infections were identified in 920 neutropenic patients during 9,582 days of neutropenia for an overall rate of 48.3 per 100 neutropenic patients, or 46.3 per 1,000 days at risk. The rate of bloodstream infection per 100 neutropenic patients was 13.5 (gram-positive, 9.2; gram-negative, 4.8; and Candida 1.2). Other site-specific rates were: urinary tract, 5.7; respiratory tract, 5.5; thrush, 6.6; skin, 3.4; and gastrointestinal tract, 3.4. Among 392 pathogens identified, there were 137 (35%) gram-positive cocci, 105 (27%) gram-negative rods, 70 (18%) Candida, 37 (9%) gram-positive rods, 22 (6%) viruses, and 15 (4%) Aspergillus.

The rate of both overall and site-specific nosocomial infections in neutropenic patients is high. Neutropenia is a significant intrinsic risk factor that should be addressed in surveillance programs. Infection control and infectious diseases practitioners may need to modify techniques for surveillance, control, and management of infection in this population.

To better assess the risk of exposure to bloodborne pathogens following puncture injuries due to needles removed from intravenous(IV) lines.

Tertiary care community medical center.

A convenience sample of hospitalized patients requiring IV piggy-back medications.

Examination of 501 IV ports of peripheral lines, heparin-locks, and central venous lines for visible blood and testing the residual fluid in the needles removed from these ports for the presence of occult blood by using guaiac-impregnated paper.

The proximal ports of central venous lines and heparin-locks were statistically more likely to contain visible blood than proximal and distal ports of peripheral lines (17% and 20% versus 1% and 3% respectively, P<0.05). Similarly, needles removed from proximal ports of central venous lines and heparin-locks were statistically more likely to contain occult blood than those from peripheral lines ( 11% and 14% versus 2%, respectively, P<0.05). Only two needles removed from IV lines without visible blood contained occult blood: one from the proximal port of a central line and another from a heparin-lock. None of the needles from peripheral lines without visible blood contained occult blood.

Estimation of the risk of transmission of hepatitis B and C and human immunodeficiency virus (HIV) following injury by needles from various IV lines revealed that injury due to needles removed from peripheral IV lines and distal ports of central lines without visible blood was associated with “near zero” risk of transmission of these bloodborne infections at our medical center.

Routine serological testing of source patients involving injury due to needles removed from peripheral IV lines and distal ports of central lines without visible blood is not necessary at our medical center. Conversely, due to the relatively high rate of occult blood in the needles removed from proximal ports of central venous lines and heparin-locks, puncture injuries due to these needles are considered significant and managed accordingly.

To determine the effect of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak in a nursing home on the subsequent MRSA caseload in a closely affiliated hospital.

Observational and descriptive; routine and special MRSA surveillance data for nursing home and hospital were reviewed for a four-year period (1988 to 1991) as were records regarding patient transfers from nursing home to hospital.

The 120-bed nursing home care unit (NHCU) and the geographically separate 434-bed acute care facility (hospital) of the Portland Veterans' Affairs Medical Center (PVAMC).

Veterans hospitalized in the acute care division of NHCU.

Following the introduction of MRSA into the NHCU in December 1987, it quickly disseminated. Two to 32 newly colonized or infected patients were recognized in each quarter of the study period. Facilitywide prevalence surveys on two occasions disclosed MRSA colonization rates of 34% and 10%. During the study period, 15 to 54 (mean: 37.6) patients were transferred each quarter from the NHCU to the hospital of the PVAMC. The number of MRSA cases transferred ranged from 0 to 16 per quarter (mean: 5.4). During the same period, the total number of MRSA cases in the hospital increased, rising from 7 cases in 1987 to 16 in 1988, 48 in 1989, 34 in 1990, and 35 in 1991. The percentage of hospital MRSA cases accounted for by NHCU transfers was 0% in 1988, 38% in 1989, 12% in 1990, and 11% in 1991.

Despite the steady flow of patients between the NHCU and the hospital, the MRSA outbreak in the NHCU was associated with only a modest increase in the MRSA caseload at the affiliated hospital.