The impact of surveys on hospital infection

Journal

of Hospital

Infection

(1995)

KEYNOTE

The impact

30 (Supplement),

421-440

LECTURE

NUMBER

of surveys

4

on hospital

infection

A. M. Emmerson Department

of Microbiology and PHLS, University Nottingham NG7 ZUH, UK

Hospital,

&MC,

Summary:

The major impact of surveys of hospital infection has been the improvement in the quality of infection control programmes. The earlier surveys became an incentive to others to find out their infection rates and risk factors for infection. Surveys are now more sophisticated in design and the surveillance methods more refined, but they have had little impact on the rates of infection. Without doubt, the greatest improvements have been made by carrying out targeted surveillance with interpretive feedback to clinical staff. This has led to the use of guidelines for good practice and measures of outcome. This strategy has been shown to decrease infection rates, decrease the need for antibiotics therapy, alleviate morbidity and save on hospital costs.

Keywords:

Hospital-acquired

infection;

survey;

surveillance.

Introduction

Rates of hospital infection are commonly measured by continuous surveillance which provides general information on endemic infection throughout hospitals. In the mid-1950s in the UK a virulent strain of Staphylococcus aweus phage type 80/81 caused much morbidity and mortality and was associated primarily with surgical operations. Such was the organism’s propensity to spread and cause disease that the Central Health Services Council in the UK set up a sub-committee of the Central Health Services Committee to investigate methods for control. In the report to the Ministry of Health of 1959l mention is made of the scant attention paid to the collection of necessary information. Since that time, surveillance of hospital infection has included the isolation and identification of ‘alert organisms’. Whilst this surveillance approach is very crude, and we know predicts ~2% of impending outbreaks, hospital laboratories were able to identify S. aweus, Pseudomonas aeruginosa and Streptococcus pyogenes and report them with confidence. However, identification methods were fraught with problems and typing methods were crude. A more basic approach was the detection of tetracyclineresistant S. aweus which was used as an index of hospital-acquired infection (HAI). In the repeated prevalence surveys carried out by Ayliffe et al2 01956701/95/060421+20

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between 1967-1973 the nasal carriage of S. UUY~USresistant to tetracycline ranged from 2.4% in gynaecological patients, to 23.5% in geriatric patients. In this study, there was a correlation between nasal carriage of tetracyclineresistant staphylococci and age of patient, length of hospital stay, sex, operative treatment and treatment with tetracycline, ampicillin and nitrofurantoin. This important study involved some 3354 patients in 38 hospitals which included repeat surveys in 12 of the hospitals. Postoperative wound infections were targeted for study and these were stratified into clean, cleancontaminated and contaminated operations whether drained or not. The foundation for the study design was based on experience gained from earlier cross-sectional surveys, the overall infection rate during the period 1967-1970 involving 5670 patients was 10*4%.3 This figure of around 10% is common throughout most of the cross-sectional (prevalence) surveys carried out in Europe in the 1970s. Prevalence

surveys

Prevalence surveys provide data about hospitalized patients at one point in time and take into account the change in the period of time that infected patients stay in hospital. Prevalence surveys can be easily performed as the patient is seen only once and a ‘snap shot’ is taken at the bedside where relevant clinical information can be obtained. Prevalence surveys can be repeated at regular intervals and infection rates compared over a period of time with or without interventional infection control policies4 They can be used to establish a baseline for overall hospital-wide infection rates so that particular infection problems can be studied in depth. The act of systematically collecting, tabulating and analysing data on the occurrence of nosocomial infections became known as ‘surveillance’ and was widely practised in Europe and in United States’ hospitals throughout the 1970s. Bernander et aZ.’ studied 3657 patients in five Swedish hospitals and came up with an overall infection rate of 10.5X-a figure almost identical to the figure produced by Ayliffe in 1971. Four main sites were identified in both studies as the most frequent sites of infection, i.e. urinary tract (29-44%), surgical wound (27-34%), lower respiratory tract (ll-32%) and skin (7%). These four sites remain the commonest today and the rates of infection have changed little. In Denmark in 1958 a systematic clinical registration of all staphylococcal infections in hospitals, with line charts and standardized criteria, was set up. ,This was at a time when staphylococcal infections were prevalent in Europe, but by 1962 the system was abandoned owing to the low rate of reporting. However, surveillance of infection in Danish hospitals has been established since 1975 and was followed closely by the establishment of the Statens Seruminstitut in 1977 to assist Danish hospitals in infection control. Prototype studies performed in a single hospital led to full scale trials in 1978 and 1979 when two prevalence surveys covering 3203 patients

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in 25 hospitals (5% of acute beds) were carried out. The overall infection rates were 10.4% in 1978, and 12.1% in 1979.6 The four most frequent sites of infection were identical with those identified in the English and Swedish studies. There was a significant difference, however, in the use of antibiotics. Some 26.6% of patients in the Birmingham study were on antibiotics whilst only 15.6% of patients in the Danish study were on antibiotics. The authors commented that national prevalence studies were suitable for promoting and setting standards for surveillance-such was the impact of this study. The survey also demonstrated the cooperation which occurred amongst several regional laboratories and 25 hospitals. Differences in infection rates between various types of service were not documented in this study. In 1978, a study group on hospital infection was set up by the Public Health Laboratory Service (PHLS) Staff Committee who saw the need for a national survey of infection in the hospitals of the UK. A study, to determine the prevalence of infection amongst patients in hospitals in England and Wales, was designed in 1979 and the methods tested in a pilot study at Birmingham. A national survey, involving 43 hospitals and 18 186 patients, was completed in a two-month period in mid-1980.7 Standardized definitions of the various types of infection and the criteria for their diagnosis were used, based on those used by Ayliffe in 1971 3 whose source was Garner et aZ.8 The UK study established that 9.2% of inpatients in acute specialities had acquired an infection of one kind or another whilst in hospital. This study and the large SENIC (Study on Efficacy of Nosocomial Infection Control) project study in the US served as a stimulus for many others to embark on similar surveys of hospital infection. In 1981 the World Health Organization (WHO) convened an advisory group to consider surveillance, control and prevention of HAI. The advisory group recommended that there should be prevalence surveys to assessthe size of the problem in different parts of the world and a method was designed for collaborative surveys in hospitals in different countries. A report of the findings of those prevalence surveys made between 1983-l 985 was published in 1988.9 Standard protocols were used to measure the prevalence of HA1 in 47 hospitals in 15 countries in four continents. The prevalence rates in individual hospitals varied from 3-21% (median 8.4%). The highest rates were seen in intensive care (13*3%), surgical (13.1%) and orthopaedic wards (11.2%). As with all previous studies, urinary tract infections (UTIs) were the commonest infections with a strong link with urethral catheterization. Antimicrobials were often used (30%) in this study indicating a heavy financial cost on top of the medical burden of infection. In the discussion, the authors stressed that prevalence surveys do not directly point to the causes of the diseases that they record. Nevertheless, infection control staff continue to perform prevalence surveys. One of the largest prevalence surveys carried out to date was in Italy in 1983 and included 34 577 acute patients in 130 hospitals. The study format was similar to that of the 1979/1980 UK study and encompassed the

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Centers for Disease Control (CDC) standardized definition and criteria for classificati0n.l’ The overall prevalence of HA1 was 6.8% which is low compared with previous European surveys. The authors attributed this low level to the many low risk patients admitted to Italian hospitals often only for diagnostic purposes. Another reason for the low level which the authors suggest, was the reluctance of the ward physicians to diagnose HAI. In spite of the problems associated with studying large numbers of patients in 142 hospitals spread throughout the country, the organizers recognized the many tangible benefits emanating from the study. The results of the survey were widely discussed, there was heavy press coverage and presentations were made at several scientific conventions. Formal courses were organized at national level for infection control nurses and professional infection control personnel were appointed; such was the educational impact of the nationwide study. At a similar time, a national one day prevalence survey of HA1 was carried out in 106 Belgian acute care hospitals involving 8723 patients of whom 6130 had undergone surgery.” However, surveillance was focused on three infections only; surgical wound infection, bacteraemia and UTI. This study produced valuable information and demonstrated the association of increased HA1 with increased length of hospital stay. Prevalence varied considerably among different specialities and bacteraemia was strongly associated with the presence of an intravenous catheter and UT1 with a urethral catheter. Once more, the authors stressed the benefits of such a study, namely the enthusiastic response of the committees of hospital hygiene and the numerous requests for further implementation of the study. They concluded that their results should be an incentive to others to scrutinize their current techniques, methods and indications, and to bring them to accepted standards. By the mid-1980s prevalence surveys were being carried out with standardized protocols and definitions of infection and information was recorded on WHO standardized forms. The prevalence survey carried out in Czechoslovakia in 1984 was processed and analysed by computer at the Institute of Hygiene and Epidemiology in Prague.” The Belgian study was also analysed by computer and included a number of error checks. Prevalence surveys by now had become more sophisticated in design but little impact had been made on rates of HA1 although a number of risk factors had been identified. The turning point came in 1985 when French and colleagues carried out repeated prevalence surveys in the same 1400-bedded teaching hospitals over a period of three years.4 Although the prevalence of communityacquired infections remained constant the HA1 rate fell progressively following the introduction of a general infection control policy. The greatest impact was the fall in UT1 rates following the introduction of a specific urethral catheter policy; these benefits persisted even when the results were adjusted for patient risk factors, which varied between surveys.

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Computerization of laboratory reports, improved access to surveillance data from May 1986 and the efforts of the infection control teams were directed towards high-risk areas revealed by the surveys. By now the prevalence survey protocol was simple to administer and the entire hospital was surveyed on a single day by a team of seven to nine trained staff. More importantly, the results of each survey were available four to six weeks after the survey day; the details of the microcomputer program will be discussed in a subsequent section. A similar prevalence survey was carried out territory-wide in Hong Kong in 1987. This compared HA1 rates in large and small hospitals with variable infection control resources.13 The results emphasized the importance of performing surveys of infection for each locality and the need to avoid undue extrapolation of epidemiological data obtained elsewhere. One of the most under-mentioned studies is one reported from a rehabilitation centre in Leiden, in The Netherlands, in 1988.14 This paper describes the progress made between 1981-1986 in a 320-bed skilled nursing facility. As a result of a sustained infection control programme, with regular weekly feedback meetings, the number of treatments for UT1 fell by 74% and the number of antibiotic courses for recurrent UTI, decreased from 18 to 6%. The most important strategy was the restriction of use of longterm indwelling urethral catheters. Two national prevalence surveys are worthy of mention, firstly the Spanish surveyI (EPINE Working Group, 1990) and the second UK study.16 The Spanish study was conducted in 123 hospitals and included 38 489 patients; the largest multicentre prevalence study yet published. The overall prevalence of HA1 was 9.9% with the most common infections being urinary tract (27*7%), surgical wound (22.7%), lower respiratory tract (15.4%) and bacteraemia (10.6%). The study protocol had been widely tested on previous occasions and was conducted during a two week period. Although the findings were in keeping with those of other similar surveys an aetiological diagnosis was made in 58% of the infections-a very commendable figure. The second national UK prevalence study was carried out during 1993/ 1994 and involved 156 hospitals and 37 000 patients. The study was carried out in two month phases but owing to the lack of sufficient laptop computers the survey had to be carried out over five two-month periods, i.e. a total of a year before the final patient was surveyed.16 Prolonged delays between completion of the surveys and publication is a common feature of most surveys. Not so, the European Prevention of Infection on Intensive Care (EPIC) study which was carried out on a single day, 29 April 1992; preliminary results were available six months later.17 The UK study should have preliminary results available within six weeks of completing the survey. The problems lie, not with the speed in producing the results, but with their interpretation.

426

A. M. Emmerson Incidence

surveys

Incidence surveys are usually performed by studying the patients’ medical records after hospital discharge and rarely during hospitalization. Since the surveys are often retrospective in nature there is a chance, that in the fullness of time, all the patients’ diagnostic results have found their way back into the case records. Sadly, hospital patient records are far from complete and are often disorganized, illegible and on occasions unintelligible. Standards of record keeping are improving and this in part may be due to clinical audit of medical records. The strict definition of incidence is the number of new cases of nosocomial infection that occur per unit population at risk over a given period of observation. More often the ‘attack rate’ is used, i.e. the proportion of exposed individuals who become infected over the entire period of exposure or duration of hospitalization. Since incidence surveys cover the period during which the patient develops, suffers and improves from an infection (a tine film exposure) the rates are often much less than prevalence rates-on average by half or 5% incidence. Incidence surveys are expensive, time-consuming but they do produce more accurate data for assessing the magnitude of HAI. The most frequent adaptation of incidence surveys to make them more manageable in terms of resource is to restrict the survey to high risk areas, e.g. intensive care units or to site-specific infection, e.g. postoperative surgical wound infections. The largest retrospective incidence study ever carried out was the SENIC project which was born in 1974.18 The nosocomial infections studied were limited to four major sites thought to include over 80% of all such infections. This proved to be true as nosocomial UTIs constituted 42% of the infections, surgical wound infections 24%, nosocomial pneumonia 1O%, nosocomjal bacteraemia 5% and others 19%. In each of the 338 sample hospitals, medical records were randomly selected from approximately 500 patients admitted in a 12-month period. Between April 1975 and March 1976 a total of 169 526 admissions were surveyed. The authors calculated that the nationwide nosocomial rate among the 6449 acute care US hospitals in 1975-1976 was 5.7 nosocomial infections per 100 admissions. A major ongoing study which originated in 1970 is the National Nosocomial Infections Study (NNIS) which looks at total surveillance of all admissions to a group of (voluntarily) selected hospitals and include all nosocomial infections.” Infections and total hospital discharges are reported to NNIS for each hospital service. Valuable information is available from this study largely due to the magnitude of the data source. The numbers of HAIs per 100 discharges is frequently used to assessrates but risk per discharge approach does not take into consideration the length of stay in hospital which is known to vary between different hospitals. Shorter lengths of stay increase the number of discharges and the risk of HA1 per discharge is lower.

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One of the earliest incidence studies on surgical wound infections in England and Wales was carried out by the PHLS between 1957-1959.20 The study was well planned and included three phases: an initial pilot survey in four hospitals, followed by the main survey in 11 hospitals between August 1957 to April 1959; and a short survey with an additional nine other hospitals brought in as a check on the results of the main survey. A total of 3276 surgical operations in 21 hospitals were studied clinically and in 2860 cases bacteriologically during convalescence. The study is most comprehensive and is a model for design. In September 1967 Cruse and Foord commenced a prospective study of all surgical wounds at the Foothills Hospital in Calgary, Alberta, Canada. In 1973 this group published a five year prospective study of 23 649 surgical wounds.2’ The overall infection rate was 4.75% and the clean rate 1.81%. This study is ongoing with a preliminary report on 62 939 wounds in 198022and I know that information is now available on more than twice this number of wounds. Such is the value of this data source that most of good surgical practice stems from this ongoing prospective study. Other studies pale into insignificance compared with Cruse and Foord’s work. However, smaller incidence studies have thrown up valuable information, again on the surgical front. Leigh in 198123 reported on an eight year study of postoperative wound infection in two district general hospitals and Bremmelgaard et aZ.24used a multiple logistic regression analysis to evaluate 10 risk factors. They also described a statistical model for identification of risk factors and the cost-effectiveness of using an electronic data processing system for recording continuous events. Continuous surveillance was advocated by Cruse and Foord in 1980z2 and by Gastrin and Lijvestad in 198525 who found a simple registration form simple and cost-effective to use. Subsequent studies looked at postoperative urinary tract and wound infection in women undergoing caesarian section thus emphasizing that looking simply at wound sepsis was not enough. Leigh et al. emphasized the need for careful urethral catheterization techniques to prevent the burden of bacteraemia in women undergoing caesarian section.26 A simple 10 year retrospective incidence survey of HA1 in a DGH was carried out by Raine27 who found that there had been an overall reduction in infection from 7*6-3.9%. He concluded that the reasons for the fall in the infection rate was probably multifactorial although there was an increased infection control awareness. This kind of awareness and positive attitude to surveillance systems was stressed by Poulsen and Jepsen2’ on their questionnaire to surgeons throughout surgical and gynaecological departments in Denmark. Such a high degree of concern about infection surveillance was voluntary and not through any pressure from the state. Surveillance

The SENIC study suggested that an important component of an effective nosocomial infection control programme was a system for monitoring and

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reporting true nosocomial infection rates.18 The problems of measuring effectiveness of infection control strategies is linked to the difficulties in devising appropriate surveillance systems for measuring HAI. The word ‘surveillance’ means literally ‘supervision, close observation . . . to watch or guard over a person, especially over a suspected person, a this sounds very much like prisoner or the like, often spying’. Ironically keeping an eye on a patient in isolation for an infectious disease! Beneson in 1970 described surveillance as the continuing scrutiny of all aspects of a disease that are pertinent to effective control.29 It is also the act of systematically collecting, tabulating, analysing and disseminating data on the occurrence of nosocomial infections. One of the main problems of surveillance of HA1 is that measuring infection rates has become more important than achieving defined measures of process and outcomes. Some examples of outcome objectives have been described: to reduce the risks of HAI; to reduce morbidity and mortality; and to reduce the costs to the patients, the hospital and the health care system.30 Surveillance of HA1 should provide current and accurate information on the distribution of infection in the population of patients studied and on the factors that contribute significantly to infection in order to contain them. This requires full utilization of existing sources of information supplemented by periodic surveys. In the early 1970s it was common practice in hospitals with an infection control interest to record all infections because they were there. Little effort was made to use the information and little feedback was given to the clinicians. This form of surveillance became known as comprehensive (total) hospital-wide surveillance and formed the basis of most of the early prevalence surveys. Even today, continuous surveillance is recognized by some as an integral part of infection control programmes31 although many now practise selective surveillance in response to resource limitation and for more meaningful information. Surveillance is also used to detect changes in the patterns of disease and to identify outbreaks. Such information is used to direct infection control activities in order to evaluate prevention and control and will assist in the planning of services and the allocation of resources. There are a number of different surveillance methods in use but all are plagued with the paucity of medical information. Anyone who has had experience with examining patients’ medical notes will realize that they are often disorganized, incomplete, illegible and often unintelligible. Often, quite basic information is missing such as the weight of the patient or when a catheter was inserted. ‘Gold standard’ surveillance is a comprehensive method of surveillance which is carried out by experienced, trained infection control personnel utilizing all sources of information. Such a system is used as the reference method against which all other surveillance systems are measured. The gold standard method is very time-consuming but it cannot be assumed to detect all HAI; this would entail long-term postdischarge surveillance.

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The crude overall nosocomial infection rate is the total number of nosocomial infections at all sites (e.g. UTIs, pneumonias, surgical wound infections, blood-stream infections etc.) divided by a measure of the population at risk (e.g. the number of admissions, discharges, or patient days). However, this method does not provide a means of adjustment for patients’ intrinsic infection risk or extrinsic risks associated with exposures to medical intervention that could lead to infection (e.g. ventilator use and nosocomial pneumonia). Such rates should not be used for interhospital comparison. The simplest way to collect information is to record laboratory and clinical information into a ledger. Unfortunately, this basic system is cumbersome and data retrieval is far too laborious unless ‘alert organisms’ only are recorded. Relevant and manageable information can be kept in the laboratory using T shapes, coloured cards and a display board such as the stratoplan (Peter Williams Ltd). This system was used successfully for a number of years3’ before being overtaken by the Kardex system.33 Similar systems lend themselves readily to computerization which will be discussed later in this presentation. Bedside surveillance of patients with serious infections, such as septicaemia and meningitis provide useful links with clinicians and nurses and provides clinical and microbiological data on these infections. Some use a purpose designed form, e.g. sentinel system, whereby information is collected according to a predetermined format. If the format is numerical then information can readily be computerized. Transcription errors can be minimized by capturing information directly onto portable laptop computers.‘6 Modest laboratory-based surveillance remains commonplace in the UK today. Early data collection forms have been replaced by more specific reviews of laboratory records and patients’ notes. Such methods are, however, insensitive and full clinical surveillance is preferred. Speciality (or service) specific infection rates are an improvement over crude overall HA1 but they do not take into account the variations in the distribution of different risk factors associated with infection in those areas. Site-specific infection rates by speciality do adjust for variation in the distribution of the types of infection but are still of limited use for interhospital comparison. The NNIS system emphasizes the importance of nosocomial infection surveillance data that adjusts for specific infection risks in order to provide better interhospital comparison of infection rates. The infection surveillance components covered by NNIS are hospital-wide, intensive care unit, high risk nursery and surgical patients; risk-specific rates are calculated.34 Surveillance methods In an attempt to define limited surveillance methods suitable for the UK, a joint study was set up by the PHLS, between the Division of Hospital Infection and the Communicable Disease Surveillance Centre. The aim of the study was to assess the effectiveness of eight different surveillance methods in detecting hospital infection and to determine the time required

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for data collection. The eight methods were compared with a reference method using standardized definitions of infection. The proportion of HA1 detected ranged from 30-71% and the time for data collection ranged from 1*2h/lOO b ed s/ week to 6.5 h/100 beds/week. The reference method took 18.1 h/100 b ed s/ week. Laboratory-based ward liaison surveillance was judged to be the most effective and efficient method.35 Data collection is the most time-consuming element of surveillance and selective surveillance methods are the only realistic ways for small infection control teams to operate on a daily basis. In UK health authorities, the infection control nurses (ICNs) often have responsibility for more than 1000 beds and with existing resources it would be impossible to produce hospital-wide rates for all types of infection except during a prevalence survey. Surveillance outcome Despite the limitations of comparing infection rates, surveillance has been shown to be an integral component of an infection control programme although not all ‘surveillance’ prevents infection. The SENIC study found that hospitals reduced their HA1 rate by approximately 32% if their infection surveillance and control programme included four components: appropriate emphasis on surveillance activities and vigorous control efforts; at least one full-time ICN per 250 beds; a trained hospital epidemiologist; and feedback of wound infection rates to surgeons.” However, in the mid-1970s, only 0.2% of US hospitals had programmes that were effective in reducing all the four major types of infection. Although about one-third of HA1 in the US hospitals could have been prevented, by 1976 only about 6% were actually being prevented.36 A subsequent survey in 1983 identified increased surveillance activity but due to lack of resources it was estimated that control programmes were only capable of preventing 9% of infections.37 One major outcome identified by the NNIS programme was that the use of devices such as urethral catheters, ventilators and central lines is the single largest determinant of HA1 rates, more significantly than the degree of illness of the patient. However, NNIS data is time-consuming to collect; it occupies most of the time of a single ICN in a 300-bed hospital and half the time of three ICNs in a 600-bed or larger hospitals. It is obvious that surveillance is of great value in identifying HA1 but the method chosen must reflect the resources available and the extent of the problem. Post-discharge surveillance Escalating medical care costs during the last decade and the introduction of day care surgery have resulted in shorter hospital stays and higher volumes of outpatient surgical procedures. A prospective survey of postoperative wound infection of 1086 inpatients and 156 day cases revealed an overall infection rate of 6*7%.38 Of patients whose wounds became infected, 34 (410/)o cases were diagnosed in hospital and 49 (59%) cases were

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dignosed in the community. In a literature review by Holtz and Wenzel 1992, 20-70% of postoperative surgical site infections did not become apparent until after the patients’ discharge.39 Post-discharge infections are more likely to occur in patients with ‘clean’ wounds and in those with shorter length of stay.40 Self-reporting by patients either through postcards given to the patient at time of discharge or through questionnaires mailed at specified intervals after discharge, e.g. for hip replacement at one, three and 12 months are practical ways of collecting additional information. Whilst the response rate is only at about 60%, nevertheless it will allow a realistic re-adjustment to be made to what may be perceived as a low or ‘satisfactory’ clean sepsis rate. Surveillance and use of computers Mainframe computers and more recently microcomputers have been shown to be useful tools to support infection control data-collection and reporting of surveillance information. Information from prospective surveys of hospitalized patients can be fed into the computer and a variety of multivariate analyses performed. Error checks can be built into the system and interim reports or day work sheets can be produced. In the prevalence survey performed by French et al. in 198541the results were coded by the survey team and then transferred to a specially written dBase11 (Ashton-Tate, Culver City, California) program for a Victor (Sirius) 9000 microcomputer with 256 Kbytes of machine memory and a hard disc storage capacity of 10 Mbytes. The analysis program consists of a number of linked modules written in dBase11 command file language. The system was designed to be easy to use for non-experts and is menu driven. However, the users found that dBase11 was relatively slow and clumsy when handling quantitative data but the use of computer analysis was essential to the survey. At the simplest level, infection control personnel use computer-generated lists of organisms grouped by hospital area (ward, operating theatre, etc.), consultant or service.42 These lists of ‘alert organisms’ and clusters may be generated automatically each day and may be supplemented by random enquiries.43 The software can be programmed to flag up infection rates exceeding an expected threshold or a particularly high rate reading statistical significance, i.e. an epidemic.44 Small hand-held computers facilitate the collecting of information at ward level and the information can be subsequently down-loaded to a larger computer for subsequent analysis. Improvements in portable (laptop) computers’6 and pen-computing (e.g. Tandy Grid, UK) have further simplified the process. Further improvements are being made by accessing hospital data systems so that departmental networking facilitates the sharing of information. More recently. Aavitsland and colleagues analysed the records from the 1991 Norwegian study using WHO/CDC Epi-Info software.45 Prevalence rates were compared using x2 statistics and prevalence rate ratios with

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95% confidence intervals. In 1992 Glenister et al. during their study of surveillance methods for detecting HAI, computerized their data by use of Fox-Base and Epi-Info version 3 (CDC) software packages and an Apricot Xen-i computer.35 The data were double entered for verification of patient identification and infection data. The consistency of the data was checked using logical and range checks. Any inconsistencies were corrected by using the original data collection form. Statistical analysis was performed using Epi-Info, SPSS/PC + (Statistical Package for Social Sciences) and GLIM (Generalized Linear Interactive Modelling) statistical packages. In 1989, the European Office of the WHO introduced a system for monitoring HA1 as part of the organization’s strategy for improved delivery of health care. As part of the package, a software program named WHOCARE, was made available.46 The widespread use of this package encouraged a coordinated approach to computer-assisted monitoring of HA1 in critically ill patients. The DANOP-DATA system is a microcomputer system designed for local (ward) surveillance of postoperative surgical wound infections using a minimum Basic Data Set. The prototype software, written originally in Danish, was first implemented at a regional Danish hospital in 1987 but is now available throughout Europe. The DANOP-DATA program is written for the MS- or PC-DOS version 2.0 or later version. The programe will run on the IBM PC/XT/AT/P52 or compatible and requires at least 512 KB RAM and supports CGA, Hercules EGA or VGA screen standard.47 The WHO initiative in using a simple computer package for surgical wound infection surveillance has created greater awareness and resulted in a number of new schemes in the participating countries for the promotion of the concept of HA1 control by continuous surveillance and feedback. It has also been an incentive for the development of similar systems adapted to local needs. In 1990, a new infection surveillance software package called EUROPEGASE was introduced which made possible the European Multicentre nosocomial infection surveillance programme which is in progress in many European hospitals; each software can be operated in English, French, German, Italian and Spanish.48 The institutions of varying sizes and activities have all used the same software to collect data and have conducted surveillance schemes based on the recommendation of the Council of Europe. ‘EUROPEGASE’ can be operated on IBM-PC or compatibles. It requires a minimum capacity of 640 Kbytes of RAM memory and a hard disc of 5 Mbytes. The software chosen for the second national survey of infection in the UK, 1994, was Epi-Info version 5.01 which is a suite of programs produced through the collaboration of the Division of Surveillance and Epidemiological Studies, CDC, Atlanta, Georgia, USA and the Global

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Program on AIDS, WHO, Geneva, Switzerland. The PC-compatible portable computer manufactured by Olivetti (Al2 notebook) proved to be effective and reliable.i6 At this meeting we will hear more about the use of computers to facilitate data handling or infection control, e.g. Alert 2000 (a DOS-based software package) and computerized graphics (Harvard Graphics). Nevertheless, whatever the degree of computer sophistication used the quality of the analysis is primarily based on the quality of the information obtained about the infections studied. Resources for infection

control

In 1955, Colebrook suggested that every major hospital should appoint a full-time Infection Control Officer (ICO) with both bacteriological and epidemiological duties.49 Brendon Moore and colleagues also described a scheme whereby a whole-time ICN should be appointed and one of her functions was to perform surveillance.” Today the ICN has to work hard to avoid spending all her/his time in performing surveillance. In 1979, a survey was undertaken by a PHLS/NHS working party to collect information regarding infection control organization in England and Wales and to provide a base-line for further studies.‘l The conclusions were that an organization existed in virtually all acute hospitals and that an ICO and ICN existed in about 90%. There was an uneven distribution of ICNs, in many health regions, 75% or more hospitals had such appointments but there were less than 60% in others and 50% or less in two regions. In the same year, hospitals were being recruited to participate in the first national survey of infections in hospitals in England and Wales. A presumption of willingness to contribute was inferred from the rapidity with which each hospital had responded to the earlier survey carried out by Knappett in 1979. Although 77 hospitals responded indicating their willingness to participate in the study, and the criterion for inclusion was an established Infection Control Team (ICT, ICO and ICN), only 45 agreed to collaborate and 43 eventually completed the survey.7 In 1986, a repeat survey of infection control organization in hospitals in England and Wales was carried out.52 Questionnaires were distributed to hospitals and returns were obtained from 180 of 200 (90%) health districts covering 95% of acute and 85% of ‘other’ hospitals listed. Ninety-eight percent (98%) had an ICO and 92% an Infection Control Committee (ICC). The proportion of health districts with an ICN had risen from 64% (1979) to 89% (1986) and the regional variation seen in 1979 was no longer marked. A further repeat study carried out in 1993 will be presented at this conference. In the 1979 UK study, it was calculated that one full-time ICN was responsible for 741 acute beds; the figure for 1986 had in fact worsened to one ICN for 785 beds. In such circumstances the ICN can only function in a fire fighting capacity and has insufficient time and resources to identify

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those aspects of hospital practice which significantly contribute to infection and which require change.53 Early information from the second national UK study indicates that a great improvement has been made between 1986-1994 with one ICN being responsible for 390 acute beds.16 The total number of ICOs seems to have remained much the same (264 in 1986, 241 in 1994). The improvement in ICN resources may be a reflection of the recognition of the need to control HA1 coupled with the firm guidance on hospital infection control issued by the joint DHSS/PHLS Hospital Infection Working Group.54 The Cooke Report, as it is generally known, will be updated and republished in 1994. The majority of ICTs in the UK are often poorly resourced and carry out little surveillance. A typical situation is for a microbiologist with two sessions (approximately 7 h per week) as the ICO and one ICN to serve a major acute hospital plus neighbouring long-stay unit and nursing homes. Attempts have been made to cost and fund infection control programmess and these costs are quite substantial; nevertheless, the costs of having an infection control programme have been calculated to equal the amount saved by preventing HA1 when approximately 6% of the infections are prevented.56 Furthermore, few ICTs have the benefit of general management and resource input at a level recommended by the 1988 Cooke Report.54 The need for a contingency allocation for extra costs in the event of an outbreak of infection has been confirmed by recent experience.” A factor which was underlined in the 1986 survey of IC organization in hospitals in England and Wales was the major commitment of medical commitments of medical microbiologists to infection control. They were generally members of the ICC and 63% were chairmen; an average minimum of 23% of their professional time was spent in infection control matters.52 Education

in infection

control

In order to get the best out of any survey of infection, the ICT should be properly trained and experienced in infection control surveillance. Staff should be able to utilize all sources of clinical, microbiological and epidemiological information to maximize data collection. As the result of many prevalence and incidence surveys ICTs have built up substantial expertise in case finding and the confidence to diagnose infection. Survey teams have been helped by the availability of definitions of infectionss’58’59 and glossaries of terms. It is now common practice to train or familiarize survey teams with the survey methodology before the survey takes place so that information is collected and recorded in a uniform manner. The study by Glenister et aL6’ examplifies the value of training surveillance staff centrally. In the second national UK survey of infections in hospitals, the ICTs from 1.56 centres were trained centrally by the study coordinators.‘6 In addition to the specific education and training required to perform surveys, ICTs receive education from a number of professional societies

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and bodies. These include the Society for Healthcare Epidemiology of America (SHEA), the Hospital Infection Society (HIS), the Association for Practitioners in Infection Control (APIC), the Infection Control Nurses’ Association (ICNA) of the British Isles and many others, some of which come under the auspices of the International Federation of Infection Control (IFIC). Further educational support and training is provided by CDC Atlanta, Georgia, the Communicable Disease Surveillance Centre (CDSC) Colindale, London and the Statens Serum Institute, Copenhagen, Denmark, The Royal College of Pathologists of London require, as part of their examination procedure, evidence of education and training in infection control. In future, all microbiologists in the UK will need to maintain and update their education as part of Continuing Medical Education (CME). Infection control will play a major role in CME for ICOs. Plans are now underway to set up a course for infection control personnel leading to the award of a Diploma in Infection Control. This will be a joint venture between the PHLS and HIS and the London School of Hygiene and Tropical Medicine. Currently, the HIS and the Division of Hospital and Respiratory Infection, Central PHLS, London, provide a one week residential course on infection control for trainee microbiologists. The Hospital Infection Research Laboratory at Birmingham has for many years, under the direction of Professor G. A. J. Ayliffe, been the source of much information and advice on all infection control matters. The Association of Medical Microbiologists (AMM) organize a number of one day courses on the management of infection control. In addition, ICNs are educated on the ENB 329 foundation course in Infection Control Nursing and are able to pursue degrees in infection control (e.g. BSc at Surrey University and MSc at Manchester University, UK). Standards for infection control in hospitals have now been published and these offer firm guidance on management structure and responsibilities in infection control, policies and procedures, microbiological services, surveillance and education.63 This document outlines the educational needs of ICTs and the resource required for this. In the UK, there are a number of accreditation schemes which take into account the educational requirements of ICTs. The scheme run by the Clinical Pathology Accreditation (UK) Limited has 44 standards, one of which (D14) states the requirements of an ICO and an ICC. ‘There should be a written policy describing all aspects of infection control, and there should be an infection control committee of which a nominated consultant in microbiology must be a member. ‘Q The main standard concerns staff development and education. The King’s Fund Organizational Audit has developed an Infection Control Standard (Standard 7) which emphasizes the need for an effective hospital-wide programme for the prevention, detection and control of

436

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infection. The audit team conducts their own inspection of hospitals and offers accreditation to hospitals that show compliance with their standards. As infection control has developed as a speciality and ICTs have surveyed patients for HA1 so too have infection control societies, journals and books developed. Infection control societies have embarked on ambitious training programmes for their trainees and education forms a major part of their activities. Meetings and journals are platforms for communication and sharing experiences. Surveys of infection have provided much needed information and form the basis for debate and education. Federations of infection societies have been formed throughout Europe and many travelling scholarships are awarded annually to trainee infection control personnel. Quality

assurance

in infection

control

Quality assurance is best described as a process of assessment in order to maintain or improve quality. In 1976, the Joint Commission on Accreditation of Healthcare Organization (JCAHO) in the US added to its standards for accreditation, the presence of an infection surveillance and control programme in accredited hospitals. This move gave added incentive for hospitals to perform surveillance but there remains numerous pitfalls in calculating and subsequently comparing rates so much so that surveillance methods must be validated. Glenister et ~1.~’ performed surveillance sensitivity and specificity and compared these with results from the gold standard or reference method. One interpretation of the SENIC data would be that such efforts were operative in reducing rates in hospitals committed to a great deal of surveil1ance.i’ This is confirmed by the results of Cruse and Foord, who showed lower postoperative wound infection rates performed by surgeons who were made aware of their own rates through objective surveillance.” The recognition that infection control is a key factor in the quality of medical care and cost-effectiveness has been slow to filter through to the management of the NHS in the UK although the costs of HA1 were clearly presented by Currie and Maynard in 1989.63 HAIs prolong the length of hospital stay and account for substantial morbidity and mortality. With the current emphasis on early discharge, in the US spurred on by the prospective payment plan known as DRG (Diagnosis-related groups) it is likely that HA1 may appear to be falling indicating improvement in overall quality. This is due partly to early discharge and failure to detect post-discharge infected cases. In the US, accreditation of hospitals requires continued monitoring of HAI rates and antibiotic use. In the UK, extension of the Resource Management Initiative and the move towards more detailed clinical audit demands greater knowledge of these and other aspects of patient care. In the UK’s first steps towards ‘quality assurance’, interest is now being shown in potential ‘clinical outcome indicators’ in assessing the quality of care patients receive in hospital.64

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Quality is more than consumer satisfaction; it includes elements of appropriateness, accessibility, effectiveness, acceptability and efficiency. Infection control is an appealing starting point for quality assurance in that it is clearly relevant to patient care (staff safety) and can lead to specific improvements in practice (in terms of effectiveness and economy) by the adoption of agreed policies and procedures.‘j’

Impact

on infection

rates

In recent times there have been a small number of well-designed studies which have demonstrated the positive impact of surveys of infection. Raine in 1991, reported on a retrospective study of HA1 surveillance data from 1978-1988 and showed a reduction in the incidence rate from 7*6-3.9%, while there was a simultaneous 25% increase in throughput of patients.66 The reduction in the incidence of HA1 was considered to be multifactorial but a major component appeared to be the feedback of information to staff and increased awareness of the infection control programme. It was felt that these measures could be used as an outcome measure to reflect the quality of care in hospitals. French and colleagues were able to repeat six prevalence surveys in a large teaching hospital over a period of three years of a general infection using a large trained team.4 After the introduction control policy, the prevalence of HA1 fell linearly from 10+5-5.6%. After the introduction of a specific urethral catheter care policy, the prevalence of hospital-acquired UT1 fell from 3*2-2-O%. Their policies had a substantial impact on the prevalence of HA1 in Hong Kong. A more recent study reported by Aavitsland and colleagues in 1992 showed the progressive fall in HA1 rates as measured by prevalence surveys between 1979-1991 in Norway.45 The rate in 1979 was 9.0%, in 1985, 7.8% and in 1991, 6.3%. The decrease in overall prevalence rate was largely explained by the decrease in UT1 prevalence. Unfortunately, no reason is given for this decrease in that study but the paper by Zimakoff et al. quite clearly demonstrated a reduction in the use of indwelling urinary catheters as a means of reducing UTIS.~’ This was made possible by a concerted effort to encourage the use of alternative devices. The SENIC study systematically evaluated the impact of infection surveillance and control activities on nosocomial infection rates and showed quite clearly that given the resources, infection rates could be substantially reduced.‘$ Different infection control strategies have different impacts and one strategy that is very effective in preventing one type of infection may fail in another situation. Although the SENIC study is not without its faults and is considered outdated by some observers (the study was started in 1974, but the results were not published until 1985) it remains a substantial piece of work which has pointed the way for subsequent surveys.@

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I should

like

to thank

Louise

Spry

for

expert

secretarial

assistance.

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