Infection Surveillance Program Research Articles

Study on the efficacy of nosocomial infection control (SENIC Project): results and implications for the future.

The purpose of the Study on the Efficacy of Nosocomial Infection Control (SENIC Project) was to evaluate nosocomial infection prevention and control programs in hospitals in the United States. The overall plan was to assess the surveillance and control activities in hospitals in the United States in 1970 and 1976, to measure the change in the nosocomial infection rates from 1970 to 1976 as determined from a carefully conducted retrospective chart review, and to assess the influence of changes in these programs on infection rates after controlling for other important changes that occurred during the interval. The SENIC 'bottom line' was that 32% of infections that would have occurred in the absence of well-organized infection surveillance and control programs were potentially preventable. However, only 6% of infections were actually being prevented by programs that existed in 1976. The critical components of an effective program were a balance between surveillance and control efforts, one infection control nurse for every 250 beds, a trained hospital epidemiologist, and feedback of surgical wound infection rates to practicing surgeons. In the United States, priorities for nosocomial infection prevention and control efforts include infections caused by emerging pathogens such as coagulase-negative staphylococci, enterococci, and Candida species; infections of the blood stream and surgical wounds; and infections in critical-care units. In addition, there is a critical need for timely analysis and dissemination of surveillance data and for continued training of infection control practitioners and physicians to maximize the effectiveness of prevention and control efforts.

Routine surveillance for infections in nursing homes: Experience at two facilities

Because the feasibility and usefulness of routine surveillance for infections in nursing homes has been questioned, we reviewed the elements of infection surveillance programs developed by two nursing homes using existing personnel. Although infection definitions and data collection methods differed between the two homes, both homes identified urinary and respiratory tract infections as the major endemic problems at their institutions and demonstrated important clusters of gastrointestinal tract and eye infections. Surveillance data were used (1) to identify individual patients who required follow-up by physicians, (2) to justify special infection control measures for clusters of gastrointestinal tract and eye infections, and (3) to provide the basis for in-service education in infection control. Routine surveillance for infections is both feasible and an integral and valuable part of overall infection control programs at two large Maryland nursing homes.

The efficacy of infection surveillance and control programs in preventing nosocomial infections in US hospitals.

In a representative sample of US general hospitals, the authors found that the establishment of intensive infection surveillance and control programs was strongly associated with reductions in rates of nosocomial urinary tract infection, surgical wound infection, pneumonia, and bacteremia between 1970 and 1975-1976, after controlling for other characteristics of the hospitals and their patients. Essential components of effective programs included conducting organized surveillance and control activities and having a trained, effectual infection control physician, an infection control nurse per 250 beds, and a system for reporting infection rates to practicing surgeons. Programs with these components reduced their hospitals' infection rates by 32%. Since relatively few hospitals had very effective programs, however, only 6% of the nation's approximately 2 million nosocomial infections were being prevented in the mid-1970s, leaving another 26% to be prevented by universal adoption of these programs. Among hospitals without effective programs, the overall infection rate increased by 18% from 1970 to 1976.

Analysis of hospital infection surveillance data.

How often infection rates should be calculated and how large a change is required for "significance" are pertinent questions in nosocomial infection surveillance programs. A method is presented which establishes outbreak threshold infection frequencies. Comparison is direct and immediate: computation of rates or use of electronic data processing is not required. We have validated this method, using computer systems, by comparing the distributions of mean weekly incidence and prevalence statistics for each ward by nosocomial infection site in an acute care general hospital against both our theoretical outbreak threshold limits and the distribution of proven infection outbreaks. Sensitive and specific distinction between random variation or sporadic cross-infection and true persisting outbreaks requiring intervention is obtained. This approach provides a simple and timely alternative to intuitive after-the-fact interpretation of infection patterns which is applicable to infection surveillance and cost-effective infection control in hospitals of all sizes.

Current Approach to Prevention and Treatment of Pseudomonas aeruginosa Infections in Burned Patients

The extensively burned or severely injured patient is at increased risk of wound infection as well as of infection of other organs as a result of various degrees of impairment of host defense mechanisms. The incidence of burn wound and other infections increases as the severity of injury increases. The ease with which gram-negative, opportunistic organisms, especially Pseudomonas aeruginosa of either endogenous or exogenous origin, can colonize and invade the immunosuppressed patient demands an active infection-surveillance program. Topical therapy for burn wounds with any of three available agents has significantly reduced the occurrence of invasive pseudomonas burn-wound sepsis, but none of the agents sterilize the burn wound, and the microbial flora of the burns of any given patient may escape from control and invade viable tissue. Clinical identification and biopsy confirmation of invasive burn-wound sepsis necessitates changes in both wound and general care, with surgical and antibiotic treatment guided by the extent and depth of wound invasion. Immunologic prophylaxis and treatment of pseudomonas infections, although attractive, remain of unverified clinical effectiveness. Effective treatment of pseudomonas septicemia secondary to invasive burn-wound sepsis and of pseudomonas infections in other organs is dependent on early diagnosis, appropriate antibiotic therapy guided by sensitivity testing, and adequate surgical intervention when required.

Nosocomial infection following prostatectomy in a new urology department.

Summary— A significant improvement in the incidence of urinary tract infection following transurethral resection of prostate was obtained during the first 4 years of a new urology department. These results, aided by wound infection rates derived from the Hospital Infection Surveillance programme, suggest the desirability of urology departments being separate, specialised units and point to the usefulness of an Infection Control Team.

CRC Handbook of Hospital Acquired Infections

In the first half of the 1970s, a revolution occurred in the management of nosocomial infections in US hospitals. In 1970, fewer than 5% of hospitals had organized infection surveillance and control programs, but by 1977 the great majority had fullor part-time infection-control nurses maintaining surveillance over infectious complications of hospitalization and assisting infection-control committees in formulating and applying methods of controlling and preventing them. This dramatic emergence of a new discipline stimulated an outpouring of scientific articles, training courses and manuals, and guidelines. By the late 1970s, this information explosion whetted appetites for general textbooks and other means of collecting and organizing information on the new surveillance and control technologies. Through the 1970s, the only widely read volume covering a broad range of subjects on infection control was the practical handbook<i>Infection Control in the Hospital</i>, published by the American Hospital Association. Finally, in 1979, the textbook<i>Hospital Infections</i>

The usefulness of a conceptual model in the study of the efficacy of infection surveillance and control programs.

To identify characteristics and activities that should be studied in evaluating the efficacy of infection surveillance and control programs (ISCPs), we developed a conceptual model for use in designing the data collection forms and analytic strategies for the Study on the Efficacy of Nosocomial Infection Control. The model emphasizes the prevention of infection by improving patient-care practices. From information collected during the hospital interview survey, we found substantial gaps between what should be practiced and what is; moreover, hospitals varied substantially in their approaches to improving these practices. The model and these diverse findings suggest ways in which hospitals can improve their ISCPs.

Progress report on the evaluation of the efficacy of infection surveillance and control programs

The main objective of the Study on the Efficacy of Nosocomial Infection Control (SENIC Project) is to determine whether infection surveillance and control programs have reduced the rates of nosocomial infection in United States hospitals. To study this question, we stratified all hospitals in the SENIC target population into 16 design strata defined by categories of a surveillance and a control index derived from hospitals' responses to a preliminary screening questionnaire, and estimated the nosocomial infection rates among 339,044 randomly selected patients admitted in 1970 and 1975 through 1976 to 338 hospitals selected randomly from the 16 design strata. Finding that the over-all infection rates, standardized for important confounding variables or covariates, in hospitals with higher intensity programs had increased less from 1970 to 1975–1976 than those of hospitals with low intensity programs would indicate the efficacy of these programs. Potentially important confounding variables and covariates being studied include individual patient risk factors, hospital characteristics and the completeness of hospitals' medical records. Since only the first has been explored sufficiently, no conclusions on efficacy can yet be drawn. The analytic techniques were illustrated with preliminary data on infection rates at the four individual sites of infection.

Techniques and uses of nosocomial infection surveillance in U.S. hospitals, 1976–1977

From personal interviews in a representative sample of hospitals, we found that 97 per cent of them had some type of infection surveillance system; most involved continuous, hospital-wide surveillance, written definitions of infections, active case-finding methods and basic analytic techniques. Infection control nurses spent an average of about half of their time on surveillance. In larger hospitals (≥ 200 beds), the heads of the infection surveillance and control programs reported a greater awareness of most nosocomial infections if they were in hospitals with more intensive surveillance systems, and most indicated that surveillance data were used for a variety of specific purposes. Although 81 percent of persons who described surveillance reported using surveillance data in inservice education, only 31 percent of U.S. staff nurses recalled its having been presented. “Clean” wound, surgeon-specific rates of surgical wound infection were reported back to surgeons in only 16 percent of the hospitals. Ninety-seven percent of the hospital administrators believed that surveillance data are not a hindrance in defending the hospital against litigation for alleged malpractice, and 65 percent considered the information more often a help.

Disadvantages of infection surveillance by medical record chart review

Cost-effective balance of priorities in infection surveillance and control program activities is an important consideration. The value and methodology of surveillance is a subject of increasing discussion. Victoria General Hospital has maintained a comprehensive, computer-assisted prospective surveillance program since 1977. In light of recent publications and in conjunction with planning further refinement of our computer program, a study comparing our current methods versus utilization of retrospective medical record chart review was undertaken. Comparison of hospital-acquired infections during the first quarter of 1979 as identified by routine surveillance and/or by medical records review showed medical records review to be less reliable. Maintaining an ongoing prospective surveillance program with monitored sensitivity and specificity also offers other distinct advantages. Cost-effective balance of priorities in infection surveillance and control program activities is an important consideration. The value and methodology of surveillance is a subject of increasing discussion. Victoria General Hospital has maintained a comprehensive, computer-assisted prospective surveillance program since 1977. In light of recent publications and in conjunction with planning further refinement of our computer program, a study comparing our current methods versus utilization of retrospective medical record chart review was undertaken. Comparison of hospital-acquired infections during the first quarter of 1979 as identified by routine surveillance and/or by medical records review showed medical records review to be less reliable. Maintaining an ongoing prospective surveillance program with monitored sensitivity and specificity also offers other distinct advantages.

The SENIC Project. Study on the efficacy of nosocomial infection control (SENIC Project). Summary of study design.

With the emergence of nosocomial infections as a serious problem among US hospitals, the Center for Disease Control undertook in 1974 a nationwide study to evaluate approaches to infection control. The three-phased project, now known as the Study on the Efficacy of Nosocomial Infection Control, or SENIC Project, was designed with three primary objectives: 1) to determine whether (and, if so, to what degree) the implementation of infection surveillance and control programs (ISCPs) has lowered the rate ofnosocomi al infection, 2) to describe the current status of ISCPs and infection rates, and 3) to demonstrate the relationships among characteristics of hospitals and patients, components of ISCPs, and changes in the infection rate. With data collection completed in a nationally representative sample of hospitals, analysis is underway to identify approaches to infection control that are most effective for the least cost to hospitals and to point out additional specific questions to be answered by future research.

The emergence of infection surveillance and control programs in US hospitals: an assessment, 1976.

To assess the current state of hospitals' infection surveillance and control programs (ISCPs) nationwide and to provide a sampling frame for selecting hospitals for later phases of the SENIC Project, the authors mailed a screening questionnaire in March, 1976, to virtually all US hospitals; 86% of those in the SENIC target universe responded. Of these, 64% (2299) reported that their ISCPs were being supervised by a physician or a microbiologist with special interest in infection control, and 42% had an infection control nurse (ICN), or equivalent, working at least half time. In contrast to the supervisors, most of the ICN's had recieved special training in hospital infection epidemiology and spent the majority of their time doing surveillance. Almost all hospitals (87%) had practiced some form of infection surveillance. Almost all hospitals (87%) had practiced some form of infection surveillance, with half reporting very active programs. Larger hospitals with ISCP staff tended to use active clinical casefinding methods, while smaller hospitals tended to use passive techniques. Most hospitals (76%) were collecting relatively large numbers of environmental cultures routinely, although a growing number (about 25%) had reduced or discontinued this practice. Routine culturing was more often performed in hospitals employing passive surveillance methods. Although the adoption of selected infection control policies and practices has varied widely, chronological data indicate that a major infection control movement has emerged since 1970.

Effect of an infection surveillance and control program on the accuracy of retrospective chart review.

The primary analyses of the SENIC Project (Study on the Efficacy of Nosocomial Infection Control) will test the association between the presence of infection surveillance and control programs (ISCPs) and changes in nosocomial infection rates (NIRs) as measured by retrospective chart review (RCR). If the establishment of an ISCP affects the quality or completeness of information important for diagnosing infection by RCR, the analyses could be biased (i.e., there could be an increased chance of a Type I or Type II error). To determine whether this type of "ISCP effect" on the accuracy of RCR is likely to occur, the authors carried out a prospective intervention study in one hospital where 1) nosocomial infections among a pre-ISCP cohort of patients were detected by prospective data collection (PDC), 2) the hospital's first ISCP was instituted, and 3) infections were identically studied by PDC exactly two years later. Several months after the end of the second PDC, a team of trained chart reviewers read the medical records of the patients in both study cohorts and abstracted all clinical data bits used for diagnosing nosocomial infection. By a nonparametric matched correlation analysis, no significant change was found in the amount of relevant clinical information recorded in the medical records, and sensitivity and specificity did not change significantly. The authors conclude that, if an ISCP effect on RCR accuracy is present at all, it must be small.

The infection control nurse in US hospitals, 1976-1977. Characteristics of the position and its occupant.

Within the past decade, the infection control nurse (ICN) has become an important element in organized infection surveillance and control programs. Before 1970, only a few hospitals (6%) had an ICN, but, by 1977, over 80% had hired at least one ICN, the majority of those hospitals having done so since 1973. To determine the characteristics of the position and its occupant, the authors analyzed data from interviews with a representative sample of ICNs from 347 hospitals nationwide, conducted in 1976-1977 as part of Phase II of the Study on the Efficacy of Nosocomial Infection Control (SENIC Project), the Hospital Interview Survey. Results varied most widely by hospital size. The ICN in the smaller hospitals (less than or equal to 300 beds) typically worked only part time in infection control, spending the rest of her or his time as a nursing supervisor. The ICN in the larger hospitals (greater than 300 beds) generally worked full time but actually worked less time in relation to the number of beds; she or he also had completed a higher level of nursing education and had attended more infection control courses. The ICN was typically a woman in the young or middle age group who had worked in her current hospital six years altogether--two of them in infection control--and was receiving a supervisor's salary. Most ICNs were under the Nursing Service Department but generally looked to the physician in the infection control program for advice or supervision.

The "hospital epidemiologist" in U.S. hospitals, 1976-1977: a description of the head of the infection surveillance and control program. Report from the SENIC project.

As part of the first two phases of the SENIC Project (Study on the Efficacy of Nosocomial Infection Control), information was collected from the heads of the infection surveillance and control programs (ISCPs) in U.S. hospitals. The data were analyzed to describe these respondents and to determine whether differences among them were related to their areas of professional training or to characteristics of the hospitals where they were located. The findings indicate that the ISCP heads constitute a very heterogeneous group, with substantial differences in age, professional training (40% are pathologists), characteristics of their medical practices, memberships in professional organizations related to infection control, time spent in ISCP activities, approach to epidemiologic problems, and opinions on the preventability of nosocomial infections and the seriousness of infection problems in their hospitals. These differences are related strongly to the ISCP heads' professional training, size of hospital, and, to a lesser extent, medical school affiliation, but there is little evidence that the differences are related to regional or urban-rural location or type of ownership of the hospitals. The average ISCP head estimates that about half of all nosocomial infections are preventable, but these estimates vary inversely with tenure in the position and the tendency to approach a clinical problem epidemiologically.

Invited remarks

One goal of the Study on the Effectiveness of Nosocomial Infection Control (SENIC) is to determine which components of infection surveillance and control programs are effective in reducing nosocomial infections. In designing SENIC, it was found impossible to conduct a prospective study for several reasons. First, the ethical question of withholding a beneficial procedure arose. Second, since surveillance procedures are part of infection control programs, the act of observing procedures constituted part of an infection control program. Therefore, it was decided instead to survey medical records from a sampie of United States hospitals.

Nosocomial infections: an overview

The results of an ongoing surveillance program for nosocomial infections in an 800-bed general hospital are presented, and considerations in conducting infection control programs in hospitals are discussed. The surveillance program is conducted by a team consisting of a nurse-epidemiologist and three technicians. The pharmacy submits antibiotic usage reports twice weekly under the program. During the first month of surveillance, the rate of nosocomial infections was 22%; this later dropped to 5%. The majority of infections occurred in patients with increased risk factors. General principles of nosocomial infection control are reviewed with primary emphasis on three problems: (1) nosocomial pneumonias, (2) hospital-acquired urinary infections and (3) postoperative wound infections. It is concluded that personnel, including pharmacists, are the prime determinants of effective infection control.