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Prevalence of nosocomial infections in Spain: EPINE study 1990–1997
Journal of Hospital Infection (I 999) 43 (Supplement):
S 105-S I I I
Prevalence of nosocomial infections Spain: EPINE study I9904997 J. Vaqub, J. Rossell6, J. L. Arribas
and EPINE Working
in
Group
Servei de Medicina Preventiva i Epidemiologia, Vu/l d’l-lebron Hospitals, 129 Ff Vail d’l-lebron, Autonomous University, Barcelona 08035
Summary: From 1990, a study on the prevalence of nosocomial infections has been carried out yearly in Spanish hospitals. Acute care hospitals with more than 50 beds were involved on a voluntary basis. In 1990, 123 hospitals participated and by 1997 the number of hospitals had reached 214. The objective of the study is to examine the situation in each hospital, and to collect data across the country, by means of a common protocol. The overall prevalence of nosocomial infections has significantly decreased in Spain. The prevalence of infected patients has been about 7% in the three last studies. The prevalences for urinary tract infections and surgical wound infections have decreased, while prevalences for lower respiratory tract infections and bacteraemia have increased. Urinary tract infections have occupied the first position over the eight surveys. Second place was taken by surgical wound infections from 1990 to 1995, and by lower respiratory tract infections in 1996-1997. With the exception of Intensive Care Units, the prevalence of nosocomial infections has been decreasing in all hospital areas. The mean age of hospitalized patients has increased, so has the proportion of patients with one or more intrinsic risk factors and the proportion of those with one or more instrumentations. The proportions of patients with a short or a very long hospital stay have increased, revealing a change that no doubt reduces nosocomial infection rates. The use of antimicrobial drugs has shown a significant increase, from 33.8% of patients in 1990 to 35.8% in 1997. 0 1999 The Hospital Infection Society Keywords:
Prevalence study; nosocomial infections;
Introduction Surveillance of nosocomial infections is an essential tool for achieving control and prevention. At present there is a consensus that surveillance is effective in reducing infections,’ and for this reason its development is important in all hospitals. The EPINE study is a uniform surveillance tool that the Spanish Society of Preventive Medicine has made available for Spanish hospitals. The EPINE study consists of performing an exhaustive cross-sectional survey in acute-care
0 195-670
I /99/OSO IO5 + 07 $12.00/O
main sites of infection;
trends; antibiotic
prescription.
hospitals, with the objective of determining the prevalence of nosocomial infections (NI). This is a simple epidemiological design in the wide range of surveillance systems available today. It offers the advantage that it can be carried out by all hospitals quickly and without sophisticated techniques. As hospitals use a common protocol, the study allows comparison of results among them and facilitates reports at several territorial levels. Prevalence surveys have great practical and scientific interest in understanding the evolution of nosocomial infections using results from repeated comparable studies;21 and this is the
0 I999 The Hospital
Infection
Society
S106
current situation in Spain after eight nationwide prevalence studies. The object of this paper is to present the main trends observed in the period 1990-1997 for all the hospitals studied.
Methods Data collection has been developed by participating hospitals using a protocol updated yearly. In the protocol, the most relevant points for the survey have been emphasized each year (composition of the working team, route through the hospital, completion of forms, checking data collected, dates of the survey), which have not changed since the first protocol in 1990. During the point cross-sectional study, which takes place in May, every in-patient is included and hospitals have two weeks for data collection. Data are collected by personnel involved in infection control at the hospital. Protocol data are collected for: age and sex, admission and infection onset dates; underlying diseases, risk factors for NI (procedures performed and devices used); surgical operation (date, degree of contamination, site, duration); the presence of nosocomial infections and its anatomic site; microbiologic studies and their results; antibiotics prescribed. For diagnosing infections, the 1988 and 1992 CDC criteria”’ are used, although asymptomatic bacteruria is not admitted as a criteria for infection. From the data collected at each hospital, an individual report is produced. Reports are also generated according to Autonomous Communities and for the whole of Spain. The study methodology has been extensively reported in previous papers.‘-” To obtain prevalences, two rates are used: the prevalence rate of infections (number of infections x loo/total patients) and that of infected patients (number of patients with infection x loo/total patients. The analysis of trends (period 1990-1997) has been carried out by means of the estimation of the odds ratio (OR) for the ordinal variable ‘year’ (considered as the unique independent variable) by rein models using aggregated data in gression, which the dependent variable has been the series
J. Vaquk et al.
of observed results (for example, infected patients) divided by the total of patients surveyed. Results are presented as point OR, its 95% confidence interval and the corresponding P value. There is a core group of 74 hospitals that has participated each year in the study; this is a group of medium sized (between 200-500 beds) or large (SO0 beds) hospitals, which differs from the rest of the hospitals, many of which are small (~200 beds). The observed trends in the core group are very similar to the entire sample. For this reason, we prefer to present the series of results of all hospitals each year; these are crude results, without adjustments or standardizations.
Results Participation
In the period 1990-1997 the total number of participating hospitals and patients surveyed has increased appreciably. The proportion of males and females has been stable and the mean of age has risen each year (Table I). Nosocomial
Infections
(NI)
In the period described, the global decrease in infections has been 18.1% and that of infected patients, 17.9%; a significant decrease. The prevalence of infected patients has been about 7% in the three last studies (Table I). The reduction has been greatest (-45%) in paediatric patients (younger than 16 years), moderate (- 19.5%) in patients aged 65 years or more, and least in the mean age group (-7.3%). Patients aged >64 years have shown levels above the total yearly prevalence. Areas
and hospitals
The prevalence of NI has diminished in all admission areas with the exception of Intensive Care Units (ICUs), mainly in the last two years, after a moderate decrease previously. The greatest decrease took place in paediatrics and surgery. Large hospitals have shown the highest
8.9% 7.8% 7.5-8.0
7.6% 8.1% 24.4% 6.7% 6.3% 7.5% 8.5%
9.9% 8.5% 8.2-8.7
Prevalence rate of patients with NI by hospital area: Medicine 8.4% Surgery 8.8% Intensive care 26.1% Paediatrics 8.8%
Prevalence of patients with NI by size of hospital: Large hospitals (>500 beds) 7.9% Medium sized hospitals (200-500 beds) 8.6% Small hospitals (~200 beds) 8.6%
of Nosocomial Infections of patients with NI inerval eight years
Prevalence rate Prevalence rate 95% confidence Trend over the
135 42185 50.5 24.5
123 38489 49.2 24.4
Hospitals included in analysis Number of patients surveyed Age (mean) in years Standard deviation
1991
6.9% 6.8% 8.1%
7.7% 7.3% 23.5% 5.7%
8.5% 7.3% 7.0-7.5
163 44343 51.0 24.5
1992
Prevalence of nosocomial infections in Spanish hospitals, EP(NE (990- I997 1990
I
EPlNElResults
Table
186 49689 52.4 24.3
1994
6.1% 7.3% 7.7%
7.0% 7.4% 22.9% 6.4%
6.1% 7.4% 7.8%
6.9% 7.8% 22.8% 5.8%
8.4% 8.3% 7.1% 7.3% 70-7.5 6.9-7.4 OR = 0.976 (0.97 I-0.982);
171 46983 51.9 24.4
I993
P
6.3% 6.7% 7.3%
6.4%
22.8%
6.9% 6.8%
8.0% 6.9% 6.6-7 I
201 51339 53.5 24.2
I995
6.2% 7.4% 8.0%
7.6% 7.0% 23.5% 6.5%
8.4% 7.2% 7.0-7.5
206 51961 54.4 23.9
1996
6.9% 7.2% 7.5%
6.9% 6.9% 26.1% 5.2%
8.1% 6.9% 6.7-7.2
214 51674 54.7 24.2
I997
S108
J. Vaquk et al.
rates and smallest ones in prevalence has been types of hospitals, and medium sized hospitals Main
sites
the least. A reduction observed in all three was most intense in (Table I).
of NI
In the eight studies, urinary tract infections (UTIs) have always taken first place when analysing infections by site. In second place have been surgical site infections (SSI) from 1990 to 1995, but in 1996 lower respiratory tract infections (LRTI) were in this position. The proportion of UTI, SSI an the ‘other’ sites have significantly decreased, while LRTI and bacteraemias (BACT) have increased (Table II). The observed increase in the proportion of SSI in 1993, is associated with the implementation of the new criteria for surgical site infections published by the CDC.6 Surgical
Risk factors
The prevalence of closed urinary drainage (as a proportion of total urinary drainage systems recorded), peripheral catheter, central catheter, central catheter with peripheral insertion, parenteral nutrition and immunosupression have increased. Only the prevalence of urinary drainage has decreased. Parenteral nutrition, tracheostomy, mechanical ventilation and nasogastric tube remain stable. The marked increase in use of peripheral catheters is noteworthy. The proportion of patients without any hospital instrumentation is noticeably diminishing. There is a slight general trend in increase of hospital procedures.
operations
Surgical operations had been performed on approximately one third of surveyed patients, although with a significant trend to decrease. The proportion of clean surgery has remained stable at 50% of surgical procedures performed. During the study period, a significant reduction in patients with SSI has been observed, as has the prevalence of patients with SSI in clean surgery (Table II). It is also important to note the continuous rise in the proportion of patients with a preoperative stay in the range of l-3 days. Underlying
consistent decrease in individuals without any underlying disease has been observed. Conversely, the proportion of patients with one or more underlying disease has increased.
diseases
The proportion of patients with neoplasms has shown a slight increase; the prevalence of diabetes has increased sharply, as has that of renal failure; the prevalence of obesity has fallen over the period 1990-1996, but increased in 1997; pressure ulcers have shown a slight increase in surveys. A falling trend in imrecent munodeficiency, cirrhosis, drug addiction and malnutrition has occurred. Coma has shown a minor decrease, while neutropenia has remained steady. In the study period a continuous and
Prevalence
length
of stay
In the eight surveys, the percentage of patients with lengths of stay less than 15 days has inCI 1.067-1.074; creased (OR = 1.07; 95% P
Microbiological
diagnosis
In NI, the proportion of positive microbiological diagnoses has increased; from 58% in 1990 to 62.3% in 1997 (Table II). Conversely, a small but significant decrease in the proportion of infection due to Gram-negative rods has been observed, whilst the Gram-positives have significantly increased. Gram-negatives have represented approximately 50% of the diagnoses in each year, and the Gram-negatives about 40%. Eschez&hia coli has remained in first place as an aetiologic diagnosis in NI over all the periods studied, at around 16% per annum, followed by Pseudomonas aevginosa and StaphyZococcus aweus. In fourth place is Enterococcus faecalis and in fifth, from 1995, S. epidevmidis.
II
Proportion of patients with NI by site: Urinary tract infection Trend over eight years Surgical site infection Trend Lower respiratory tract infection Trend Bacteraemia Trend Remaining sites Trend Proportion of surgical patients Trend Prevalence rate of patients with surgical site infections (clean surgery) Trend Proportion of microbiological diagnosis available Trend Proportion of patients receiving antibiotics Trend 19.3% 17.8% 9.2% 26.1% 33.9% 2.5%
60.1%
21.4% 16.9% 8.9% 26.5% 34.8% 3.5%
59.7%
34.5%
22.7% 15.4% 10.5% 23.7% 3 I .4% 3.5%
58.0%
33.8%
34.9%
27.6%
I992
26.3%
1991
27.7%
I990
Primary site distribution, prevalence of nosocomial infections in clean surgery
EPlNElResults
Table I994
I995
I.001 (1~007-1~01);
P
36.1%
OR = I .O I 6 ( I .006-I .027); P
59.9%
2.2%
35.8%
62.3%
2.8%
32.5% 32.1%
13.6% 12.6%
20.8%
20.6% 20.6%
21.7%
19.6%
25.4%
I997
17.4%
27.7%
I996
60.9%
OR = 0.96 (0.94-0.98); P~0.00 I 60.9% 60.2%
25.5% 25.1% 25.9% OR = 0.97 (0.96-0.98); P
I993
SIIO
S. auseus has decreased (11.1% of all microorganisms isolated in 1990 and 7.9% in 1997), and S. epidevmidis increased (5.1% in 1990; 6.8% in 1997). In the last 4 surveys methicillin-resistant S. aUreUS has been steady at around 2.5% of all isolations.
Use of antimicrobials The prevalence of use of antimicrobials has shown a statistically significant increase from 33.8% in 1990 to 35.8% in 1997, with a peak of 36.1% in 1996. The highest prevalence has been in the ICUs each year, and stable over the years. Trends to increased use of antimicrobials have been detected in Medicine, from 32.7% in 1990 to 36.7% in 1997. In the last study, in 1997, the antibiotic most often prescribed was ciprofloxacin at 9.4% of the total, followed by amoxicillin-clavulanate at 8.9%.
Discussion The EPINE study, besides providing results about surveillance of NI, has contributed to a widespread understanding of the methodology of surveillance of NI in Spanish hospitals, and raised the awareness of healthcare personnel of the importance of their prevention. The information given to each hospital by the study, has facilitated accurate guidance and organisation of control tasks, and for this reason we believe the study has been a positive influence in diminishing infections. By means of EPINE a decrease in the prevalence of NI in Spanish hospitals has occurred and, from now, considering the stabilization of the prevalence of NI in the last years, a notable effort to continue the decrease may be needed. We consider that the prevalence observed during the last years is acceptable in the European context.6,” The study has been widely accepted, as is demonstrated by the steady increase in participating hospitals, approaching to the maximum of all possible (275). The great stability of EPINE results is noteworthy. There are characteristic patterns related to patients’ distribution, risk factors, microbiological cultures, infections and antibiotic use,
J. Vaqu6 et al.
by area of admission, type of hospital and ward, which have remained constant over the period. Within this general stability, several trends have been detected, showing an evolution of the problem of NI in the mean term; this possibility of studying trends is a particular advantage of repeated prevalence studies.2-4 The constant increase in the mean age of patients, observed in all admission areas, reflects a general population trend to ageing and to a greater age on admission to hospital. The increase has reduced in the last year and perhaps in following studies will cease. In this increase, in addition to demographic factors, some bias is present. This is produced by the increase in small hospitals studied, in which the proportion of older people is high. This situation should be studied further, as changes in dependency might become important. The increase in elderly people observed in EPINE is associated with a slight increase in underlying diseases, although baseline severity remains stable. Intensive Care Units in the last years have not shown a consistent decrease in nosocomial infections. The recent increase in their prevalence may be related to changes in the type of patients admitted, who are increasingly debilitated, older, and with changes in sites of NI. The changes in sites of infection, with a decrease in UT1 and SSI, and an increase for LRTI and BACT, can be interpreted as an improvement in control of NIs that are most easy to prevent (UT1 and SSI), while others more complex to prevent (LRTI, BACT) have shown a relative increase. The increasing use of closed urinary drainage systems is a factor clearly implicated in reducing UTI. In the decrease of SSI multiple factors are involved, such as increase in the prevalence of short stays and a decrease in longer stays, the marked increase in proportion of patients with a preoperative stay of l-3 days, and changes in surgical practice in general. The rise in use of devices and hospital procedures, as is observed for peripheral vascular catheters, is associated with these changes, although a cross-sectional design like EPINE cannot determine whether this relationship is a cause or a consequence of the changes.
Sill
EPINE study
There has been a marked and satisfying increase in microbiological diagnoses in nosoIt is notable that there has comial infections.ll been a progressive increase of S. epidevmidis, associated with changes in patient characteristics and infection sites. The frequency of methicillin-resistant S. auwus is low and steady, and this is not a major problem at the moment in Spanish hospitals. The conclusions drawn from EPINE are that the situation in Spanish hospitals entails reducing risk for in-patients, with a decrease in prevalence of nosocomial infections despite the detection of a few undesirable trends. This obliges us to intensify efforts in out-patient, inpatient and preventive areas. EPINE is a simple tool for surveillance that, in our opinion, has contributed benefits, in the sense of improving surveillance methodology and general understanding of nosocomial infections, and for the implementation of prevention and control measures.
References 1. Centers
for Disease Control. Public Health Focus: Surveillance, Prevention and Control of Nosocomial Infections. &ZA0I0? 1992; 41: 783787. 2. French GL, Cheng AFB, Wong SL, Donnan S. Repeated prevalence surveys for monitoring effectiveness of hospital infection control. Lancet 1989; 2: 1021-1023. 3. Spencer RC. Prevalence studies in nosocomial
infections.
Euv 3 Clin Microbial
ITzfect Dis 1992;
11: 95-98. 4. French GL. Repeated surveillance surveys. In: Surveillance of nosocomial infections. AM Emmerson, GAJ Ayliffe, eds. Baillidve’s Clinical Infectious Diseases 1996; 3: 179-195. 5. Garner JS, Jarvis WR, Emori TG, Horan TC, Hughes JM. Centers for Disease Control definitions for nosocomial infections, 1988. Am J Infect Control 1988; 16: 128-140. 6. Horan TC, Gaynes RP, Martone WJ, Jarvis WR, Emori TG. Centers for Disease Control definitions of nosocomial surgical site infections, 1992: A modification of CDC definitions of surgical wound infections. Infect Control Hasp Epidemiol 1992; 13: 606-608. 7. EPINE Working Group. Prevalence of hospitalacquired infections in Spain. J Hosp Infect 1992; 20: 1-13. 8. Campins M, Vaque J, Rossello J et al. and EPINE Working Group. Nosocomial infections in pediatric patients: A prevalence study in Spanish hospitals. AnzJ Infect Control 1993; 21:
58-63. 9. Vaque J, Rossellh J, Trilla A et al. and EPINE Working Group. Nosocomial infections in Spain: results of four nationwide serial prevalence surveys (EPINE project, 1990-1993). Infection Control and Hospital Epidemiology 1996; 17: 293-297. 10. Vaque J y Grupo de Trabajo EPINE. Evolution de la prevalencia de infecciones nosocomiales en Espafia. EPINE 1990-1997. Madrid: Sociedad Espafiola de Medicina Preventiva, Salud Publica e Higiene, 1998. 11. Emmerson AM. The impact of surveys on hospital infection. 3 Hosp Infect 1995; 30 (Suppl): 421-440.
S 105-S I I I
Prevalence of nosocomial infections Spain: EPINE study I9904997 J. Vaqub, J. Rossell6, J. L. Arribas
and EPINE Working
in
Group
Servei de Medicina Preventiva i Epidemiologia, Vu/l d’l-lebron Hospitals, 129 Ff Vail d’l-lebron, Autonomous University, Barcelona 08035
Summary: From 1990, a study on the prevalence of nosocomial infections has been carried out yearly in Spanish hospitals. Acute care hospitals with more than 50 beds were involved on a voluntary basis. In 1990, 123 hospitals participated and by 1997 the number of hospitals had reached 214. The objective of the study is to examine the situation in each hospital, and to collect data across the country, by means of a common protocol. The overall prevalence of nosocomial infections has significantly decreased in Spain. The prevalence of infected patients has been about 7% in the three last studies. The prevalences for urinary tract infections and surgical wound infections have decreased, while prevalences for lower respiratory tract infections and bacteraemia have increased. Urinary tract infections have occupied the first position over the eight surveys. Second place was taken by surgical wound infections from 1990 to 1995, and by lower respiratory tract infections in 1996-1997. With the exception of Intensive Care Units, the prevalence of nosocomial infections has been decreasing in all hospital areas. The mean age of hospitalized patients has increased, so has the proportion of patients with one or more intrinsic risk factors and the proportion of those with one or more instrumentations. The proportions of patients with a short or a very long hospital stay have increased, revealing a change that no doubt reduces nosocomial infection rates. The use of antimicrobial drugs has shown a significant increase, from 33.8% of patients in 1990 to 35.8% in 1997. 0 1999 The Hospital Infection Society Keywords:
Prevalence study; nosocomial infections;
Introduction Surveillance of nosocomial infections is an essential tool for achieving control and prevention. At present there is a consensus that surveillance is effective in reducing infections,’ and for this reason its development is important in all hospitals. The EPINE study is a uniform surveillance tool that the Spanish Society of Preventive Medicine has made available for Spanish hospitals. The EPINE study consists of performing an exhaustive cross-sectional survey in acute-care
0 195-670
I /99/OSO IO5 + 07 $12.00/O
main sites of infection;
trends; antibiotic
prescription.
hospitals, with the objective of determining the prevalence of nosocomial infections (NI). This is a simple epidemiological design in the wide range of surveillance systems available today. It offers the advantage that it can be carried out by all hospitals quickly and without sophisticated techniques. As hospitals use a common protocol, the study allows comparison of results among them and facilitates reports at several territorial levels. Prevalence surveys have great practical and scientific interest in understanding the evolution of nosocomial infections using results from repeated comparable studies;21 and this is the
0 I999 The Hospital
Infection
Society
S106
current situation in Spain after eight nationwide prevalence studies. The object of this paper is to present the main trends observed in the period 1990-1997 for all the hospitals studied.
Methods Data collection has been developed by participating hospitals using a protocol updated yearly. In the protocol, the most relevant points for the survey have been emphasized each year (composition of the working team, route through the hospital, completion of forms, checking data collected, dates of the survey), which have not changed since the first protocol in 1990. During the point cross-sectional study, which takes place in May, every in-patient is included and hospitals have two weeks for data collection. Data are collected by personnel involved in infection control at the hospital. Protocol data are collected for: age and sex, admission and infection onset dates; underlying diseases, risk factors for NI (procedures performed and devices used); surgical operation (date, degree of contamination, site, duration); the presence of nosocomial infections and its anatomic site; microbiologic studies and their results; antibiotics prescribed. For diagnosing infections, the 1988 and 1992 CDC criteria”’ are used, although asymptomatic bacteruria is not admitted as a criteria for infection. From the data collected at each hospital, an individual report is produced. Reports are also generated according to Autonomous Communities and for the whole of Spain. The study methodology has been extensively reported in previous papers.‘-” To obtain prevalences, two rates are used: the prevalence rate of infections (number of infections x loo/total patients) and that of infected patients (number of patients with infection x loo/total patients. The analysis of trends (period 1990-1997) has been carried out by means of the estimation of the odds ratio (OR) for the ordinal variable ‘year’ (considered as the unique independent variable) by rein models using aggregated data in gression, which the dependent variable has been the series
J. Vaquk et al.
of observed results (for example, infected patients) divided by the total of patients surveyed. Results are presented as point OR, its 95% confidence interval and the corresponding P value. There is a core group of 74 hospitals that has participated each year in the study; this is a group of medium sized (between 200-500 beds) or large (SO0 beds) hospitals, which differs from the rest of the hospitals, many of which are small (~200 beds). The observed trends in the core group are very similar to the entire sample. For this reason, we prefer to present the series of results of all hospitals each year; these are crude results, without adjustments or standardizations.
Results Participation
In the period 1990-1997 the total number of participating hospitals and patients surveyed has increased appreciably. The proportion of males and females has been stable and the mean of age has risen each year (Table I). Nosocomial
Infections
(NI)
In the period described, the global decrease in infections has been 18.1% and that of infected patients, 17.9%; a significant decrease. The prevalence of infected patients has been about 7% in the three last studies (Table I). The reduction has been greatest (-45%) in paediatric patients (younger than 16 years), moderate (- 19.5%) in patients aged 65 years or more, and least in the mean age group (-7.3%). Patients aged >64 years have shown levels above the total yearly prevalence. Areas
and hospitals
The prevalence of NI has diminished in all admission areas with the exception of Intensive Care Units (ICUs), mainly in the last two years, after a moderate decrease previously. The greatest decrease took place in paediatrics and surgery. Large hospitals have shown the highest
8.9% 7.8% 7.5-8.0
7.6% 8.1% 24.4% 6.7% 6.3% 7.5% 8.5%
9.9% 8.5% 8.2-8.7
Prevalence rate of patients with NI by hospital area: Medicine 8.4% Surgery 8.8% Intensive care 26.1% Paediatrics 8.8%
Prevalence of patients with NI by size of hospital: Large hospitals (>500 beds) 7.9% Medium sized hospitals (200-500 beds) 8.6% Small hospitals (~200 beds) 8.6%
of Nosocomial Infections of patients with NI inerval eight years
Prevalence rate Prevalence rate 95% confidence Trend over the
135 42185 50.5 24.5
123 38489 49.2 24.4
Hospitals included in analysis Number of patients surveyed Age (mean) in years Standard deviation
1991
6.9% 6.8% 8.1%
7.7% 7.3% 23.5% 5.7%
8.5% 7.3% 7.0-7.5
163 44343 51.0 24.5
1992
Prevalence of nosocomial infections in Spanish hospitals, EP(NE (990- I997 1990
I
EPlNElResults
Table
186 49689 52.4 24.3
1994
6.1% 7.3% 7.7%
7.0% 7.4% 22.9% 6.4%
6.1% 7.4% 7.8%
6.9% 7.8% 22.8% 5.8%
8.4% 8.3% 7.1% 7.3% 70-7.5 6.9-7.4 OR = 0.976 (0.97 I-0.982);
171 46983 51.9 24.4
I993
P
6.3% 6.7% 7.3%
6.4%
22.8%
6.9% 6.8%
8.0% 6.9% 6.6-7 I
201 51339 53.5 24.2
I995
6.2% 7.4% 8.0%
7.6% 7.0% 23.5% 6.5%
8.4% 7.2% 7.0-7.5
206 51961 54.4 23.9
1996
6.9% 7.2% 7.5%
6.9% 6.9% 26.1% 5.2%
8.1% 6.9% 6.7-7.2
214 51674 54.7 24.2
I997
S108
J. Vaquk et al.
rates and smallest ones in prevalence has been types of hospitals, and medium sized hospitals Main
sites
the least. A reduction observed in all three was most intense in (Table I).
of NI
In the eight studies, urinary tract infections (UTIs) have always taken first place when analysing infections by site. In second place have been surgical site infections (SSI) from 1990 to 1995, but in 1996 lower respiratory tract infections (LRTI) were in this position. The proportion of UTI, SSI an the ‘other’ sites have significantly decreased, while LRTI and bacteraemias (BACT) have increased (Table II). The observed increase in the proportion of SSI in 1993, is associated with the implementation of the new criteria for surgical site infections published by the CDC.6 Surgical
Risk factors
The prevalence of closed urinary drainage (as a proportion of total urinary drainage systems recorded), peripheral catheter, central catheter, central catheter with peripheral insertion, parenteral nutrition and immunosupression have increased. Only the prevalence of urinary drainage has decreased. Parenteral nutrition, tracheostomy, mechanical ventilation and nasogastric tube remain stable. The marked increase in use of peripheral catheters is noteworthy. The proportion of patients without any hospital instrumentation is noticeably diminishing. There is a slight general trend in increase of hospital procedures.
operations
Surgical operations had been performed on approximately one third of surveyed patients, although with a significant trend to decrease. The proportion of clean surgery has remained stable at 50% of surgical procedures performed. During the study period, a significant reduction in patients with SSI has been observed, as has the prevalence of patients with SSI in clean surgery (Table II). It is also important to note the continuous rise in the proportion of patients with a preoperative stay in the range of l-3 days. Underlying
consistent decrease in individuals without any underlying disease has been observed. Conversely, the proportion of patients with one or more underlying disease has increased.
diseases
The proportion of patients with neoplasms has shown a slight increase; the prevalence of diabetes has increased sharply, as has that of renal failure; the prevalence of obesity has fallen over the period 1990-1996, but increased in 1997; pressure ulcers have shown a slight increase in surveys. A falling trend in imrecent munodeficiency, cirrhosis, drug addiction and malnutrition has occurred. Coma has shown a minor decrease, while neutropenia has remained steady. In the study period a continuous and
Prevalence
length
of stay
In the eight surveys, the percentage of patients with lengths of stay less than 15 days has inCI 1.067-1.074; creased (OR = 1.07; 95% P
Microbiological
diagnosis
In NI, the proportion of positive microbiological diagnoses has increased; from 58% in 1990 to 62.3% in 1997 (Table II). Conversely, a small but significant decrease in the proportion of infection due to Gram-negative rods has been observed, whilst the Gram-positives have significantly increased. Gram-negatives have represented approximately 50% of the diagnoses in each year, and the Gram-negatives about 40%. Eschez&hia coli has remained in first place as an aetiologic diagnosis in NI over all the periods studied, at around 16% per annum, followed by Pseudomonas aevginosa and StaphyZococcus aweus. In fourth place is Enterococcus faecalis and in fifth, from 1995, S. epidevmidis.
II
Proportion of patients with NI by site: Urinary tract infection Trend over eight years Surgical site infection Trend Lower respiratory tract infection Trend Bacteraemia Trend Remaining sites Trend Proportion of surgical patients Trend Prevalence rate of patients with surgical site infections (clean surgery) Trend Proportion of microbiological diagnosis available Trend Proportion of patients receiving antibiotics Trend 19.3% 17.8% 9.2% 26.1% 33.9% 2.5%
60.1%
21.4% 16.9% 8.9% 26.5% 34.8% 3.5%
59.7%
34.5%
22.7% 15.4% 10.5% 23.7% 3 I .4% 3.5%
58.0%
33.8%
34.9%
27.6%
I992
26.3%
1991
27.7%
I990
Primary site distribution, prevalence of nosocomial infections in clean surgery
EPlNElResults
Table I994
I995
I.001 (1~007-1~01);
P
36.1%
OR = I .O I 6 ( I .006-I .027); P
59.9%
2.2%
35.8%
62.3%
2.8%
32.5% 32.1%
13.6% 12.6%
20.8%
20.6% 20.6%
21.7%
19.6%
25.4%
I997
17.4%
27.7%
I996
60.9%
OR = 0.96 (0.94-0.98); P~0.00 I 60.9% 60.2%
25.5% 25.1% 25.9% OR = 0.97 (0.96-0.98); P
I993
SIIO
S. auseus has decreased (11.1% of all microorganisms isolated in 1990 and 7.9% in 1997), and S. epidevmidis increased (5.1% in 1990; 6.8% in 1997). In the last 4 surveys methicillin-resistant S. aUreUS has been steady at around 2.5% of all isolations.
Use of antimicrobials The prevalence of use of antimicrobials has shown a statistically significant increase from 33.8% in 1990 to 35.8% in 1997, with a peak of 36.1% in 1996. The highest prevalence has been in the ICUs each year, and stable over the years. Trends to increased use of antimicrobials have been detected in Medicine, from 32.7% in 1990 to 36.7% in 1997. In the last study, in 1997, the antibiotic most often prescribed was ciprofloxacin at 9.4% of the total, followed by amoxicillin-clavulanate at 8.9%.
Discussion The EPINE study, besides providing results about surveillance of NI, has contributed to a widespread understanding of the methodology of surveillance of NI in Spanish hospitals, and raised the awareness of healthcare personnel of the importance of their prevention. The information given to each hospital by the study, has facilitated accurate guidance and organisation of control tasks, and for this reason we believe the study has been a positive influence in diminishing infections. By means of EPINE a decrease in the prevalence of NI in Spanish hospitals has occurred and, from now, considering the stabilization of the prevalence of NI in the last years, a notable effort to continue the decrease may be needed. We consider that the prevalence observed during the last years is acceptable in the European context.6,” The study has been widely accepted, as is demonstrated by the steady increase in participating hospitals, approaching to the maximum of all possible (275). The great stability of EPINE results is noteworthy. There are characteristic patterns related to patients’ distribution, risk factors, microbiological cultures, infections and antibiotic use,
J. Vaqu6 et al.
by area of admission, type of hospital and ward, which have remained constant over the period. Within this general stability, several trends have been detected, showing an evolution of the problem of NI in the mean term; this possibility of studying trends is a particular advantage of repeated prevalence studies.2-4 The constant increase in the mean age of patients, observed in all admission areas, reflects a general population trend to ageing and to a greater age on admission to hospital. The increase has reduced in the last year and perhaps in following studies will cease. In this increase, in addition to demographic factors, some bias is present. This is produced by the increase in small hospitals studied, in which the proportion of older people is high. This situation should be studied further, as changes in dependency might become important. The increase in elderly people observed in EPINE is associated with a slight increase in underlying diseases, although baseline severity remains stable. Intensive Care Units in the last years have not shown a consistent decrease in nosocomial infections. The recent increase in their prevalence may be related to changes in the type of patients admitted, who are increasingly debilitated, older, and with changes in sites of NI. The changes in sites of infection, with a decrease in UT1 and SSI, and an increase for LRTI and BACT, can be interpreted as an improvement in control of NIs that are most easy to prevent (UT1 and SSI), while others more complex to prevent (LRTI, BACT) have shown a relative increase. The increasing use of closed urinary drainage systems is a factor clearly implicated in reducing UTI. In the decrease of SSI multiple factors are involved, such as increase in the prevalence of short stays and a decrease in longer stays, the marked increase in proportion of patients with a preoperative stay of l-3 days, and changes in surgical practice in general. The rise in use of devices and hospital procedures, as is observed for peripheral vascular catheters, is associated with these changes, although a cross-sectional design like EPINE cannot determine whether this relationship is a cause or a consequence of the changes.
Sill
EPINE study
There has been a marked and satisfying increase in microbiological diagnoses in nosoIt is notable that there has comial infections.ll been a progressive increase of S. epidevmidis, associated with changes in patient characteristics and infection sites. The frequency of methicillin-resistant S. auwus is low and steady, and this is not a major problem at the moment in Spanish hospitals. The conclusions drawn from EPINE are that the situation in Spanish hospitals entails reducing risk for in-patients, with a decrease in prevalence of nosocomial infections despite the detection of a few undesirable trends. This obliges us to intensify efforts in out-patient, inpatient and preventive areas. EPINE is a simple tool for surveillance that, in our opinion, has contributed benefits, in the sense of improving surveillance methodology and general understanding of nosocomial infections, and for the implementation of prevention and control measures.
References 1. Centers
for Disease Control. Public Health Focus: Surveillance, Prevention and Control of Nosocomial Infections. &ZA0I0? 1992; 41: 783787. 2. French GL, Cheng AFB, Wong SL, Donnan S. Repeated prevalence surveys for monitoring effectiveness of hospital infection control. Lancet 1989; 2: 1021-1023. 3. Spencer RC. Prevalence studies in nosocomial
infections.
Euv 3 Clin Microbial
ITzfect Dis 1992;
11: 95-98. 4. French GL. Repeated surveillance surveys. In: Surveillance of nosocomial infections. AM Emmerson, GAJ Ayliffe, eds. Baillidve’s Clinical Infectious Diseases 1996; 3: 179-195. 5. Garner JS, Jarvis WR, Emori TG, Horan TC, Hughes JM. Centers for Disease Control definitions for nosocomial infections, 1988. Am J Infect Control 1988; 16: 128-140. 6. Horan TC, Gaynes RP, Martone WJ, Jarvis WR, Emori TG. Centers for Disease Control definitions of nosocomial surgical site infections, 1992: A modification of CDC definitions of surgical wound infections. Infect Control Hasp Epidemiol 1992; 13: 606-608. 7. EPINE Working Group. Prevalence of hospitalacquired infections in Spain. J Hosp Infect 1992; 20: 1-13. 8. Campins M, Vaque J, Rossello J et al. and EPINE Working Group. Nosocomial infections in pediatric patients: A prevalence study in Spanish hospitals. AnzJ Infect Control 1993; 21:
58-63. 9. Vaque J, Rossellh J, Trilla A et al. and EPINE Working Group. Nosocomial infections in Spain: results of four nationwide serial prevalence surveys (EPINE project, 1990-1993). Infection Control and Hospital Epidemiology 1996; 17: 293-297. 10. Vaque J y Grupo de Trabajo EPINE. Evolution de la prevalencia de infecciones nosocomiales en Espafia. EPINE 1990-1997. Madrid: Sociedad Espafiola de Medicina Preventiva, Salud Publica e Higiene, 1998. 11. Emmerson AM. The impact of surveys on hospital infection. 3 Hosp Infect 1995; 30 (Suppl): 421-440.