To choose a microcomputer software package for our hospital epidemiology division, the two leading commercial software packages for infection control, AICE (ICPA, Inc., Austin, Texas) and NOSO- (Epi Systematics, Inc., Ft. Meyers, Florida), were compared for the types of epidemiologic analysis likely to be required to satisfy new Joint Commission on Accreditation of Healthcare Organizations (JCAHO) 1990 Infection Control Standards. The test dataset was a surgical database of 3,235 operations with 292 (9%) wound infections. Though NOSO- was more flexible in terms of the amount of data items one could record, it required seven times longer to learn, nine times more disk space to store and two times as long to enter cases than AICE. Six simple infection control reports (i.e., line listings, crosstabulations, stratified rates and graphs) required only seven computing steps and approximately 11 minutes to process with AICE, but 22 steps and over two hours with NOSO-3. All analytic results from AICE agreed with the results obtained with the Statistical Analysis System (SAS, SAS Institute, Inc., Cary, North Carolina), but analyses such as service-specific rates performed with NOSO- differed because of a design flaw in the NOSO- data structure.

Factors predisposing to clinically significant nosocomial infection with Xanthomonas maltophilia were examined in a matched case-control study using multivariate techniques. Sixteen cases occurred among cancer patients in a six-month period, including an apparent cluster of three cases in an intensive care unit. These infections were unusually serious; eight patients had disseminated infection caused by X maltophilia and six died as a result of their infections.

Among the 64 factors that were examined, therapy with broad-spectrum antibiotics and central venous catheterization were found to significantly increase susceptibility to infection. Therapy with imipenem was more than ten times more frequent among cases than among controls (p < .001). All fatal infections occurred in patients who had received imipenem, including two patients who died before the organism could be identified and appropriate therapy instituted.

Infection with X maltophilia should be suspected in patients who develop superinfection while receiving imipenem, and prompt therapy should be instituted to improve chances of survival. Because a common environmental source of X maltophilia was not identified, further study is necessary to determine specific preventive measures.

To examine rates of falls and injuries by clinical department, a retrospective analysis was performed of 874 inpatient falls during a one-year period in a 1,000-bed acute-care hospital. Incident reports were reviewed, and for those patients injured, medical records were abstracted. Fall rates were calculated by age, sex and service using total patient days as the denominator.

During 1983, 874 falls occurred during 282,713 adult patient days (31/104 days). Fall rates were significantly higher (odds ratio = 2.12; 95% confidence interval [CI]: 1.84, 2.45) in the neuroscience and psychiatry departments (53/104 days) compared with other adult services combined (25/104 days); this difference persisted after direct adjustment for age. Differences by clinical department persisted throughout four additional years of surveillance, although fall rates for the oncology service increased. Injuries following falls occurred among 200 (22.8%) patients.

These data indicate that falls are not random events, and that falls and injury prevention programs can be more appropriately focused by consideration of clinical department.

We controlled the spread of epidemic methicillin-resistant Staphylococcus aureus (MRSA) infection in an 884-bed veterans' facility by cohorting known active MRSA carriers and MRSA-infected patients on one nursing unit. Simultaneously, all previously-institutionalized transfers into the veterans' facility were screened with swab cultures for MRSA at the time of admission. All MRSA patients were maintained on contact (gown and glove) or strict isolation and treated aggressively with topical and enteral antibiotics with the assistance of the infectious disease consultant. The monthly incidence of new MRSA patients dropped from a maximum of 16 per month to three or less per month within six months of instituting these infection control measures. There were no further MRSA bacteremias after the establishment of the MRSA cohort in a single unit. Aggressive cohort management of known MRSA patients and screening of previously-institutionalized patients on admission for MRSA controlled epidemic MRSA in this large institution.

A cross-sectional serological survey was undertaken in 82 randomly selected high-risk healthcare workers previously vaccinated with the hepatitis B vaccine. The study design allowed for the identification and testing for hepatitis B surface antibody in equal numbers of employees in six-month intervals up to five years after vaccination. The results showed a consistent decline in antibody level with time, and an increasing proportion of participants with antibody levels below the commonly accepted protective level of ≥10 S/N (sample counts/negative control counts) radioimmunoassay units. The percent of vaccinees whose S/N ratio was greater than 10 fell from 10% at one year, to 25% at two years, to over 50% at four years. Based on these figures, as well as the financial costs of hepatitis B in employees and the predictability of booster immunization, it was possible to assess the cost benefit of a hospital policy for reimmunization. At our institution, a strategy of revaccination at fixed intervals could save up to $200,000 over a ten-year period if revaccination was not offered and vaccine efficacy declined. The information obtained should help determine the need for revaccination and the advantages and disadvantages of alternative revaccination strategies.

An anonymous national survey of a representative population of healthcare workers who were thought likely to have frequent and intensive exposures to blood and other body fluids (certified nurse-midwives [CNMs]), was conducted to assess the type and frequency of self-reported occupational exposures to blood and body fluids experienced, the extent to which barrier precautions and other infection control measures were used, whether or not reported use of barriers was associated with a lower perceived rate of exposures and factors that influenced the use of infection control procedures.

Of those responding, 74% had soiled their hands with blood at least one time in the preceding six months, 51% had splashed blood or amniotic fluid in their faces and 24% reported one or more needlestick injuries during that same period. Our study also found evidence of an association between the practice of needle recapping and the occurrence of needlestick injury (p = .003). Despite a high level of training and knowledge, only 55% reported routinely practicing universal precautions (UPs).

Several factors that potentially influenced the use of UPS were studied, including healthcare worker perceptions of risk of occupational bloodborne infection, knowledge of routes of transmission of bloodborne pathogens and rationale for not using appropriate barriers. Our data suggest that occupational exposures occur frequently and that healthcare workers' (HCWs') perceptions of risk for occupational infection play an important role in influencing use of UPS. This study emphasizes the importance of developing new strategies for UP training.

In the period 1975 to 1981, methicillin-resistant Staphylococcus aureus (MRSA) emerged as an important nosocomial pathogen in tertiary care centers in the United States. To determine if the prevalence of this organism has continued to increase, a questionnaire was sent to hospital epidemiologists in 360 acute care hospitals. A total of 256 (71%) of the 360 individuals responded. Overall, 97% (246/256) of responding hospitals reported having patients with MRSA in the period 1987 through 1989. Respondents in 217 hospitals provided estimates of the number of cases seen in 1987, 1988 and 1989. The percentage of respondents reporting one or more patients with MRSA increased from 88% in 1987 to 96.3% in 1989 (p = .0008). The percent of respondents reporting large numbers (≥50) of cases per year increased from 18% in 1987 to 32% in 1989 (p = .0006). Increasing frequency of large outbreaks was observed in community, community-teaching, federal, municipal and university hospitals.

A series of handwashing experiments using a pigskin substrate and Serratia marcescens as the contaminant compared the residual activity of a chlorhexidine detergent handwash product alone and incombination with anionic and nonionic-based moisturizing products and surfactant systems. The anionic based moisturizing products and the anionic surfactant system almost completely destroyed the residual antibacterial activity of the chlorhexidine, while the nonionic-based products had minimal effect.

To test the effects of four surgical scrub products on colonizing hand flora, 60 healthy adult volunteers were assigned by block randomization (12 subjects per group) to use one of the following formulations: 70% ethyl alcohol with 0.5% chlorhexidine gluconate (ALC); a liquid detergent base containing 1% triclosan (TRI); a liquid detergent base containing 4% chlorhexidine gluconate (CHG); a liquid detergent base containing 7.5% povidone-iodine (PI); or a nonantimicrobial liquid soap (control). Using standard protocol, subjects performed a surgical scrub daily for five consecutive days. Hand cultures were obtained at baseline and on test days 1 and 5 immediately after the scrub and following four hours of gloving. After the first and last scrubs, ALC, CHG and PI resulted in significant reductions in colonizing flora when compared to the control. Additionally, by day 5 ALC was associated with an almost 3-log reduction as compared to an approximate 1.5-log reduction for CHG and PI and less than a l-log reduction of TRI and the control (p = .009). After four hours of gloving on both days 1 and 5, microbial counts on hands of subjects using ALC, TRI and CHG were significantly lower than counts for the control (p < .001), whereas there was no significant difference in counts between the PI and control groups (p = .41). Skin assessment by study subjects rated products from least to most harsh as follows: control, TRI, CHG, ALC and PI (p = .00001). It was concluded that ALC could be an efficacious and acceptable alternative for surgical scrubbing.

This study provides an evaluation of the effectiveness of methods to increase hand-washing (HW) by nurses working in an intensive care unit. After baseline observations, two interventions were implemented in sequence: three series of classes conducted by the infection control nurse (ICN); and feedback to staff about handwashing errors on the previous day. Staff were aware that handwashing was being observed throughout the study. The educational intervention produced an immediate increase in HW that was followed by a decline to baseline rates over four weeks. Feedback produced an improvement to 97% compliance that was sustained until completion of the study. Improvement in HW compliance following specified critical procedures was also observed following interventions.

Handwashing is believed to be the most important means of preventing nosocomial infections. Previous studies of healthcare workers (HCWs) have shown that handwashing practices are poor. No one has shown that handwashing practices can be easily improved and that this prevents endemic (non-epidemic) nosocomial infection. Handwashing and infection rates were studied in two intensive care units (ICUs) of a community teaching hospital. Handwashing rates were monitored secretly throughout the study. After six months of observation, we started interventions to increase handwashing. Handwashing increased gradually, but overall rates before (22.0%) and after (29.9%) interventions were not significantly different (p = .071). Handwashing never occurred before intravenous care, whereas it occurred 67.5% for all other indications (p<.0001). When questioned, nurses felt they were washing appropriately nearly 90% of the time. Infection rates seemed unrelated to handwashing throughout the study, and no clusters of infection were detected. We conclude that handwashing rates, when measured against arbitrary but reasonable standards, are suboptimal, difficult to change and not closely related to evidence of cross-infection. Further, nurses wash hands selectively, depending on the indication for handwashing, and generally believe they are washing much more frequently than an objective observer believes they are.

An outbreak of acute gastroenteritis (AGE) occurred in a 201-bed geriatric convalescent facility in Los Angeles County during December 1988 through January 1989. The attack rate was 55% among residents and 25% among employees. Illnesses were characterized by vomiting and diarrhea to a lesser extent, and the absence of fever. Bacterial and parasitic tests in a sample of patients were negative. A 27nm small round structured virus (SRSV) was identified in one of 30 stools studied by immune electron microscopy (IEM). While rotavirus and influenza A and B were found in three, one and three cases, respectively, no alternative etiologic agent could be demonstrated for most cases. The outbreak met Centers for Disease Control (CDC) clinical and epidemiologic criteria for Norwalk-like gastroenteritis. The death rate of residents was not elevated beyond baseline during the outbreak; however, one healthy employee had diarrhea and dehydration and died after developing an arrhythmia. An autopsy showed moderate, diffuse lymphocytic and neutrophilic myocarditis, and viral studies found influenza A in left ventricular tissue. Fourteen (25%) of 57 employee cases worked in occupations without routine stool or patient contact. At least nine of these employees lacked evidence of direct fecal contact, and transmission of infection in these cases may have been airborne. (Infect Control Hosp Epidemiol. 1990;11:459-464.)