To assess risk factors for colonization and nosocomial infection with ampicillin-resistant enterococci (ARE).

Patients with ampicillin-resistant enterococci were compared retrospectively by logistic regression analysis with controls harboring susceptible strains. ARE were characterized by whole plasmid DNA analysis and restriction enzyme analysis of plasmid (REAP) DNA with EcoRI.

The study was done at a 1,125 bed, tertiary-care teaching hospital in North Carolina with patients from whom enterococci were isolated from June 1, 1989, to March 30, 1991.

The final study group comprised 44 cases with nosocomially-acquired colonization or infection with ARE and 100 controls with ampicillin-susceptible strains. Clinical and epidemiological risk factors for ARE were abstracted by chart review.

After controlling for age and site of infection, patients with ARE were more likely to have been admitted previously to our hospital and to have received third-generation cepha-losporins and clindamycin. However, only advanced age and clindamycin therapy were independently associatedwith presence of ARE. REAP with EcoRI showed 20 groups of enterococci on 19 different wards.

These results suggest that ARE are endemic and multifocal in origin in our hospital and that advanced age and use of clindamycin are important selective risk factors for ARE colonization and infection (Infect Control Hosp Epidemiol1993;14:629-635).

To describe 4 healthcare workers who developed measles despite pre-existing antimeasles antibody levels.

Hospital employees working in patient care areas from July through November 1990 were screened for measles antibody levels using a commercially available enzyme immunoassay (EIA). The clinical course and laboratory evaluation of the 4 healthcare workers who developed measles were reviewed.

An academic tertiary care children's hospital.

A convenience sample of resident physicians, nurses, ward clerks, Child Life workers, physical and occupational therapists, radiology technicians, and housekeeping staff were screened regardless of age, immunization status, or history of measles infection.

Of 1,311 employees working in patient care areas, 900 (68.6%) had sera tested for measles antibody. Fourteen (1.5%) were negative, 338 (37.6%) had low-positive antibody levels, 372 (41.3%) were mid-positive, and 171 (19%) were high-positive; 5 (0.6%) showed equivocal results. Four healthcare workers vaccinated in the past developed measles. All had positive pre-illness measles antibody levels and all had a significant rise in measles-specific IgG following infection. Three of them had received at least 2 live measles vaccinations prior to caring for patients with measles.

These cases raise concerns regarding detection of adequate protective measles immunity. We recommend that all healthcare workers observe respiratory precautions in caring for patients with measles.

To compare the efficacy of endoscope disinfection using automated and manual systems.

Prospective randomized trial.

A 1,000-bed tertiary care referral center.

All endoscopes underwent a three-stage decontamination process including brushing and cleaning with water and detergent, manual or automated disinfection with 2% glutaraldehyde, and 70% alcohol rinse with forced air drying. Cultures were obtained from endoscopes from both groups before and after alcohol rinse and then after overnight storage.

Cultures from 8/30 (27%) automated and 11/30 (37%) manually disinfected (P= 0.58) endoscopes grew gram-negative bacteria and/or nontuberculous mycobacteria before the alcohol rinse. After alcohol rinse, 3 (10%) of 30 automated and 8 (27%) of 30 manually disinfected endoscopes remained contaminated (P= 0.28). Manually disinfected endoscopes were contaminated more frequently with coliform bacteria, whereas endoscopes undergoing automated disinfection were more frequently contaminated with nontuberculous mycobacteria, but the differences were not statistically significant. After alcohol rinse and forced air drying, there was no difference in contamination rates between freshly disinfected endoscopes and those stored overnight (7/30 (23%) versus 4/30 (13%), P= 0.50). Colonoscopes and duodenoscopes were contaminated more often than gastroscopes (P=0.00001).

The persistent endoscope contamination after manual and automated disinfection indicates the importance of developing more reliable and effective disinfection methods.

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 compare the proportion of recapped needles, an injury surrogate measure, in disposal boxes on two different types of hospital units, both before and after an intervention.

Prospective nonrandomized intervention trial.

A major public teaching hospital.

Specific hospital units. We selected two types of hospital units for study: the first type of hospital unit (medical-surgical ward) had existing mounted in-bathroom needle disposal boxes, and the second type of hospital unit (intensive care unit) had unmounted needle disposal boxes in the room but not necessarily near the patient's bedside.

The installation, in the medical-surgical wards only, of mounted needle disposal boxes on the wall near the patient's bed. The box location in the intensive care units remained the same. In both types of unit, a new mailbox-slot disposal box (SAGE) also was substituted for the previous round-top container.

The baseline proportion of recapped needles in the first medical-surgical unit was 32.6% (±3.8%) and in the second medical-surgical unit it was 27.4% (± 4.0%) in the bathroom needle disposal boxes, which was similar to the observed proportion (34.7 ± 6.4%) in the intensive care unit boxes. Following the intervention, the proportion of recapped needles was significantly reduced in the disposal containers adjacent to the bedside in medical-surgical units, to 27% (a difference of 2.9 standard errors of the baseline distribution) in the first unit and 18.2% (a difference of 4.6 standard errors) in the second. In the intensive care unit, where boxes were not moved but new mailbox-types were simply substituted, no significant change was noted (36.6%, a difference of 0.59 standard errors). A statistically significant reduction was observed in the proportion of needles recapped in both wards combined following the intervention (30.2% to 26.2%, a difference of 2.9 standard errors).

Environmental changes alone are an effective means of altering the risk to healthcare workers from sharp instruments. The use of needle-box counts provides a sensitive and stable instrument to measure injury surrogates and, indirectly, behavioral change in hospital workers.

In a previous study, we found that unsolicited recommendations to physicians of medically stable patients with pneumonia to suspend parenteral antimicrobials shortened hospital length of stay (LOS) significantly. In this study, we made similar recommendations to physicians treating patients with different indications for parenteral antimicrobials, to examine the effect on LOS.

A nurse-interventionist presented randomly assigned physicians with nonconfrontational suggestions to discontinue parenteral antimicrobials by substituting comparable oral antimicrobials or stopping treatment. Patients were being treated for urinary tract infection, skin infection, or no evident infection. Blinded observers evaluated in-hospital and 30-day postdischarge patient courses. Methodologies were identical to the previous study.

There were 70 physician-patient episodes (49 intervened episodes, 21 control episodes). In 44 episodes (90%), compliant physicians discontinued parenteral antimicrobials. Compared to a median postrandomization LOS of 2.5 days (range, 0 to 40.5) for 21 patients of control physicians, the corresponding LOS for 44 patients of compliant physicians was two days (range, 0 to 8; P= 1.0), and for five patients of noncompliant physicians, five days (range, 3 to 11; P= 0.04).

The combined occurrence of all adverse events detected in this and the previous study was 11% for patients of control physicians, compared to 14% for patients of compliant physicians (P= 0.2), and 19% for patients of noncompliant physicians (P<0.05).

For patients of compliant physicians hospitalized with urinary tract infection, skin and soft tissue infection, or no evident infection, cessation of parenteral antimicrobials did not significantly shorten LOS, due to brief LOS of patients of control physicians. Patients of noncompliant physicians experienced more adverse events and prolonged LOS. The appropriateness of routine continuous use of parenteral antimicrobials in medically stable inpatients is questioned.

From April 2-23, 1992, the housekeeping staff of the University of Granada Hospital was on strike. Measures were implemented to minimize the effects of the strike on patients' health and especially to diminish the risk of hospital infection.

To assess the risk of nosocomial infection during the housekeeping personnel strike.

An 800-bed, tertiary care hospital.

A case-cohort approach was used. One hundred forty-eight infected patients (with 184 hospital infections) were detected prospectively from March 1, 1992, to May 31, 1992. A sample of 459 of the base population (patients admitted during the same period) was selected. Information on relevant risk factors for hospital infection was abstracted from patients' clinical charts after hospital discharge. Crude odds ratios and adjusted (by proportional hazards model) relative risks (RRs) for the strike period were estimated.

Risk of nosocomial infection did not increase during the strike period (multiple-risk factor adjusted RR= 0.99, 0.96 to 1.01/day of strike). Similar results were observed for major sites of infection (especially surgical wound) and major areas of the hospital (including gynecology, surgery, and intensive care).

We concluded that there was no increase in the risk of nosocomial infection during the housekeeping strike.

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 determine risk factors for Mycobacterium xenopi isolation in patients following a pseudo-outbreak of infection with the organism.

Retrospective cohort analysis of mycobacteriology laboratory specimen records and frequency-matched case-control study of hospital patients.

General community hospital.

See also page 642

For the case-control study, 13 case patients and 39 randomly selected controls with mycobacterial cultures negative for M xen-opi, frequency matched by specimen source, whose specimens were submitted from June 1990 through June 1991.

Between June 1990 and June 1991, M xenopi was isolated from 13 clinical specimens processed at a midwestern hospital, including sputum (n = 6), bronchial washings (2), urine (4), and stool (1). None of the patients with M xenopi- positive specimens had apparent mycobacterial disease, although five received antituberculosis drug therapy for a range of one to six months. Specimens collected in a nonsterile manner were more likely to grow the organism than those collected aseptically (3.1% versus 0, relative risk= infinity, P= 0.003). M xenopi isolation was attributed to exposure of clinical specimens to tap water, including rinsing of bronchoscopes with tap water after disinfection, irrigation with tap water during colonoscopy, gargling with tap water before sputum collection, and collecting urine in recently rinsed bedpans. M xenopi was isolated from tap water in 20 of 24 patient rooms tested, the endoscopy suite, and the central hot water mixing tank, but not from water in the microbiology laboratory. The pseudo-outbreak occurred following a decrease in the hot water temperature from 130°F to 120°F in 1989.

Maintenance of a higher water temperature and improved specimen collection protocols and instrument disinfection procedures probably would have prevented this pseudo-outbreak (Infect Control Hosp Epidemiol 1993;14:636-641).

The Centers for Disease Control and Prevention has issued new criteria for conversion of the tuberculin skin test; in persons over 35 years of age, an increase in induration of at least 15 mm is considered indicative of new tuberculous infection. We reviewed our experience in a tuberculosis control program in a long-term care facility to assess the applicability of the new criteria to our patient population.

Retrospective review of seven years of tuberculosis control records and outbreak investigation.

Long-term care Veterans Affairs hospital.

All patients in the facility between 1985 and June 1992 who received routine admission and annual tuberculin skin testing or who were evaluated for possible exposure to active tuberculosis. A total of 2,342 skin tests were performed.

Mean increase in skin test diameter in patients with at least two prior negative tests and known exposure to active tuberculosis was 13.9 ± 4.7 mm. Frequency distribution histograms of skin test sizes of initial tuberculin testing in the entire population indicated 10 mm induration as a reasonable criterion for initial positivity.

In our long-term care population, an increase in skin test induration of 10 mm may indicate new tuberculous infection. Criteria for skin test conversion derived from ambulatory populations in other geographic areas may not apply in all situations. Prevalence of infection with Mycobacterium tuberculosis and prevalence of skin test reactivity due to nontuberculous mycobacteria are likely to influence the predictive value of criteria for tuberculin conversion in a given population.

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.

Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological indicator that provides results within 60 minutes with three conventional, 24-hour biological indicators for monitoring flash sterilization and three chemical indicators.

Conventional biological indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout indicator tested was Attest 1291. Attest Rapid Readout detects the presence of a Bacillus stearothermophilus enzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical indicators tested included Comply, Incheque, and Thermalog S. Survival at 132°C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56°C for the three conventional biological indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological indicator, and color change for the chemical indicators. Each exposure time was replicated four times with 10 of each biological and chemical indicator per run.

The conventional biological indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The chemical indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively.

The sensitivity of the Attest Rapid Readout parallels the conventional biological indicators. These data suggest that a 60-minute rapid readout biological indicator is equivalent to the 24-hour biological indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.

The current study was designed to assess the sporicidal activity of chemical sterilants using the Association of Official Analytical Chemists (AOAC) sporicidal test. Chemical sterilants are used most commonly in the healthcare setting to disinfect medical instruments such as endoscopes. This study was undertaken to evaluate the efficacy of several newer formulations of glutaraldehydes and hydrogen peroxide as chemical sterilants.

Using the AOAC test the following agents were tested: two 2% alkaline glutaraldehydes (2% Alk-Glut), 2% acid glutaraldehyde (2% Acid Glut), 2% glutaraldehyde-7.05% phenol-1.20% sodium phenate, 10% glutaraldehyde-0.5% phenylphenol-0.1% tertiary amylphenol, and 6% hydrogen peroxide (H202). Growth in > 1 of 60 seeded penicylinders is considered by the AOAC to indicate failure of sporicidal activity,

Test results of the six disinfectants against Bacillus subtilis using the manufacturers' specified use-dilution and exposure time were: 0/60 with 2% Alk-Glut (product 1) at 10 hours, 0/60 with 2% Alk-Glut (product 2) at 8 hours, 0/60 with 2% Acid Glut at 10 hours, 2/60 with 2% glutaraldehyde-7.05% phenol-1 .20% sodium phenate at 6.75 hours, 0/60 with a 1:5 dilution (2.0% Glut) of 10% glutaraldehyde-0.5% phenylphenol-0. 1% amylphenol at 6 hours, 59/60 with a 1:20 dilution (0.5% Glut) of 10% glutaraldehyde-0.5% phenylphenol-0.1% tertiary amylphenol at 12 hours and 0/60 with 6% H202 at 6 hours. Test results against Clostridium sporogenes were: 2/60 with 2% Alk-Glut (product 1) at 10 hours, 1/60 with 2% Alk-Glut (product 2) at 8 hours, 1/60 with 2% Acid Glut at 10 hours, 2/60 with undiluted 2% glutaraldehyde-7.05% phenol-1.20% sodium phenate at 6.75 hours, 6/60 with a 1:5 dilution (2% Glut) of 10% glutaraldehyde-0.5% phenylphenol-0.1% amylpenol at 6 hours, 60/60 with a 1:20 dilution (0.5% Glut) of 10% glutaraldehyde-0.5% phenylphenol-0.1% amylpenol at 12 hours, and 0/60 with 6% H202 at 6 hours. Dilutions of 2% glutaraldehyde-7.05% phenol-1.20% sodium phenate yielded the following results against C sporogenes: 59/60 with a 1:8 dilution (0.25% Glut) at 6.75 hours, 60/60 with a 1:16 dilution (0.125% Glut) at 6.75 hours, 11/90 with a 1:8 (0.25% Glut) dilution at 12 hours, and 60/60 with a 1:16 dilution (0.125% Glut) at 12 hours.

Both 2% acid and alkaline glutaraldehydes are effective chemical sterilants. Diluting glutaraldehyde-based sterilants below 2% glutaraldehyde resulted in failure to kill spores of B subtilis and C sporogenes.