Antibiotic prescription practices, consumption and ... - Snowfall

Acta Anaesthesiol Scand 2002; 46: 1075–1081 Copyright C Acta Anaesthesiol Scand 2002
Printed in Denmark. All rights reserved
ACTA ANAESTHESIOLOGICA SCANDINAVICA
0001-5172
Antibiotic prescription practices, consumption and
bacterial resistance in a cross section of Swedish
intensive care units
S. M. WALTHER 1 ,M.ERLANDSSON 2 ,L.G.BURMAN 8 ,O.CARS 8 ,H.GILL 6 ,M.HOFFMAN 3 ,B.ISAKSSON 4 ,G.KAHLMETER 7 ,
S. LINDGREN 5 ,L.NILSSON 4 ,B.OLSSON-LILJEQUIST 8 ,H.HANBERGER 2 and THE ICUSTRAMA STUDY GROUP
Departments of 1 Cardiothoracic Anesthesia and Intensive Care, 2 Infectious Diseases, 3 Clinical Pharmacology, 4 Clinical Microbiology and Hygiene and
the 5 Pharmacy at Universitetssjukhuset, Linköping, the 6 Department of Biomedical Engineering at Linköpings Universitet, 7 Department of Clinical
Microbiology, Växjö lasarett and 8 Smittskyddsinstitutet, Solna, Sweden
Background: The purpose of this work was to study usage of
antibiotics, its possible determinants, and patterns of bacterial
resistance in Swedish intensive care units (ICUs).
Methods: Prospectively collected data on species and antibiotic
resistance of clinical isolates and antibiotic consumption specific
to each ICU in 1999 were analyzed together with answers to a
questionnaire. Antibiotic usage was measured as defined daily
doses per 1000 occupied bed days (DDD 1000 ).
Results: Data were obtained for 38 ICUs providing services to
a population of approximately 6 million. The median antibiotic
consumption was 1257 DDD 1000 (range 584–2415) and correlated
with the length of stay but not with the illness severity score or
the ICU category. Antibiotic consumption was higher in the
ICUs lacking bedside devices for hand disinfection (2193 vs.
1214 DDD 1000 , pΩ0.05). In the ICUs with a specialist in infectious
diseases responsible for antibiotic treatment the consumption
pattern was different only for use of glycopeptides (58% lower
usage than in other ICUs: 26 vs. 11 DDD 1000, PΩ0.02). Only 21%
of the ICUs had a written guideline on the use of antibiotics,
57% received information on antibiotic usage at least every 3
months and 22% received aggregated resistance data annually.
Clinically significant antimicrobial resistance was found among
Enterbacter spp. to cephalosporins and among Enterococcus spp. to
ampicillin.
Conclusions: Availability of hand disinfection equipment at
each bed and a specialist in infectious diseases responsible for
antibiotic treatment were factors that correlated with lower antibiotic
consumption in Swedish ICUs, whereas patient-related
factors were not associated with antibiotic usage.
Received 1 February 2002, accepted for publication 12 June 2002
Key words: Anti-infective agents; critical care; cross infection;
multiple drug resistance.
c Acta Anaesthesiologica Scandinavica 46 (2002)
BACTERIAL resistance to antibiotics has emerged as
an important factor influencing patient mortality
and morbidity. Although the clinical impact of resistant
bacteria is not fully known, studies of both hospi-
tal-acquired pneumonia and nosocomial bacteremia
have demonstrated an association between causative
bacteria resistance to therapeutic antibiotic agents and
worse patient outcomes (1–3). Prior antibiotic usage is
The coordinators of local ICUSTRAMA groups were at Huddinge Universitets Sjukhus: Johan Struwe; Södersjukhuset, Stockholm: Jan Häggqvist,
Johan Hulting; Akademiska Sjukhuset, Uppsala: Hans Stiernström, Elisabeth Löwdin; Mälarsjukhuset, Eskilstuna: Carl-Gustaf Sundin, Veronika
Hjorth; Nyköpings Lasarett: Ulf Riese; Universitetssjukhuset, Linköping: Olle Engdahl, Magnus Vegfors, Annette Theodorsson; Vrinnevisjukhuset,
Norrköping: Ola Lindberget, Sverker Eriksson; Lasarettet, Motala: Jan Lindquist; Länssjukhuset Ryhov, Jönköping: Peter Nordlund, Lars
Sören; Centrallasarettet, Växjö: Lena Nilsson; Länssjukhuset, Kalmar: Peråke Jarnheimer; Västerviks Sjukhus: Johan Berkius; Blekingesjukhuset
Karlskrona: Christer Nilsson, Per-Olof Eklund; Lunds Universitetssjukhus: Peter Dahm, Per Hagstam; Universitetssjukhuset MAS, Malmö: Inga
Odenholt; Kristianstad-Hässleholms Sjukhus: Keld Brodersen, Tony Eden; Helsingborgs Lasarett: Åsa Hallgärde; Länssjukhuset Halmstad: Janet
Hacklou, Södra Älvsborgs Sjukhus, Borås: Per Petersen, Anders Lundqvist; Uddevalla Sjukhus: Göran Anderzon, Martin Wahl; Norra Älvsborgs
Lasarett, Trollhättan: Sven Öberg; Kärnsjukhuset Skövde: Per Lorentzen, Sören Elowson; Lidköpings Lasarett: Robert Nyström; Centralsjukhuset,
Karlstad: Thomas Ahlqvist; Örebro Läns Landsting, Örebro: Anders Nydahl, Hans Fredlund; Falu Lasarett: Ivan Vig; Länssjukhuset Gävle/
Sandviken: Inger Riesenfeld-Örn; Bollnäs-Söderhamns Sjukhus: Bo Magnusson; Hudiksvalls Sjukhus: Ewa Risen; Östersunds Sjukhus: Caroline
Starlander, Mikael Widerström; Norrlands Universitetssjukhus, Umeå: Ola Winsö, Johan Wiström; Luleå-Bodens Sjukhus: Ivar Wizelius, Anders
Nystedt.
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one factor that predisposes to infections with resistant
bacteria (2,4,5). Frequent and extended use of antibiotics,
high staffing and frequent use of invasive procedures
make intensive care units (ICUs) a high-risk
environment for the selection and spread of antibioticresistant
bacteria. A recent consensus statement suggested
that the emergence of resistance could be better
controlled through optimization of prophylactic, empiric
and therapeutic antibiotic use (6). This could be
accomplished by education about appropriate antibiotic
use and by providing data to physicians about
the types and prevalence of resistant organisms found
in their own institution as part of an on-going surveillance
program. Tailoring of antibiotic usage to each
ICU by an antibiotic management team led by an intensive
care specialist was also suggested recently (7).
Indeed, the utility of such a strategy was shown by a
recent study in which an antibiotic management program
that used local clinician-derived consensus
guidelines embedded in computer-assisted decision
support programs was applied in a community hospital
(8).
While the prevalence of resistant bacterial strains is
currently favorable in Swedish ICUs compared with
many other European countries (9), we believe that
this could change rapidly (10). Monitoring of antibiotic
usage and resistance patterns among bacteria
are, in addition to prudent use of antibiotics and strict
barrier nursing, key elements in the strategy to control
resistance to antibiotics. Hence, the main purpose of
the present multicenter study was to monitor antibiotic
prescription and isolated organisms and their
drug susceptibility in individual ICUs and to relate
these data to clinical practices associated with the use
of antibiotics and infection control measures and patient
mix.
Methods
Questionnaires were administered by electronic mail
during the year 2000 to all Swedish adult ICUs and
departments of infectious diseases. The questions pertained
to measures that described the unit and its
workload during 1999 (number of beds, number of
patients, illness severity scores, length of stay, etc.)
and selected infection control practices.
All laboratories of clinical microbiology were contacted
and asked to provide data on cultures collected
on clinical indications from their matching ICUs during
1999. Only initial bacterial isolates were considered
and repeat isolates of the same species from
the same patient were excluded. Susceptibility testing
was performed at the time of sampling with a disc
diffusion method according to the Swedish Reference
Group of Antibiotics (SRGA). The zone breakpoints
for susceptible, intermediate and resistant strains
were defined according to SRGA (11). For the purpose
of this work decreased susceptibility to antibiotics
was defined as the proportion of isolates with intermediate
sensitivity and resistance, i.e. those separated
from the normal population of isolates. In addition,
hospital pharmacies were contacted and asked to provide
data on deliveries of antibiotics to their corresponding
ICUs during 1999. Consumption of antibiotics
was assessed as the delivery of defined daily
doses (DDD) per 1000 occupied bed days in the ICU
(DDD 1000 ). Defined daily doses is based on the average
adult maintenance dose for the primary indication
of the drug and has been established by the
WHO as a standardized basis for comparing drug
consumption (12).
Significance testing was not carried out to confirm
hypotheses postulated a priori but to explore differences
and relationships. To this end non-parametric
methods (Spearman’s rank correlation, Mann–Whitney,
Kruskal–Wallis and Fisher’s tests) were used.
Results
Responses were received from 38 ICUs providing primary
services to a population of approximately 6 million.
Ten units were located in tertiary care centres
(regional ICUs), 20 in county hospitals (county ICUs)
and eight were in local hospitals (local ICUs, Table 1).
Data regarding patient flow, infection control practices,
delivery of antibiotics and microbiology, including
resistance patterns, were received from 26 units.
Information on bacteriology and susceptibility to antibiotics
only were received from five additional ICUs,
while patient flow data plus data on the delivery of
antibiotics only was received from 31 ICUs.
Among ICU characteristics compared, only the number
of admissions and length of stay differed between
hospital categories (Table 1). The median number of
beds with a strict isolation facility per ICU was two,
although three ICUs had no such facility. The mean
length of stay in the regional ICUs was more than
twofold that in the local ICUs. Eighteen units (47%)
collected illness severity scores (APACHE II, nΩ17,
APACHE III, nΩ1), but only one unit computed a risk
of death from the scores. The mean APACHE II scores
were slightly higher in the regional ICUs compared
with units in the county and local hospitals (Table 1).
Only 3/33 (9%) ICUs had formal guidelines relating
to the minimum distance between beds in the unit.
The actual minimum distance between beds in mul-
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Table1
Intensive care unit characteristics and selected practice parameters.
Characteristics* Local hospital ICU County hospital ICU Regional hospital ICU P-value †
Annual no. of admissions median (range) 2070 (1577–4955) 1746 (591–4950) 1042 (700–1490) 0.03
nΩ5 nΩ18 nΩ9
No. of beds median (range) 8 (6–11) 8.5 (6–19) 9.5 (6–16) 0.53
nΩ5 nΩ20 nΩ8
Mean APACHE II scores median (range) 10.4 (10.0–12.8) 12.0 (8.7–16.0) 12.9 (12.7–13.0) 0.36
nΩ3 nΩ12 nΩ2
Mean length of stay (days) median (range) ‡ 1.0 (0.3–1.2) 1.4 (0.6–3.2) 2.3 (1.4–4.5) 0.01
nΩ4 nΩ18 nΩ9
Antibiotic consumption (DDD 1000 ) median (range) 1072 (807–1377) 1170 (604–2415) 1541 (584–2247) 0.18
nΩ4 nΩ17 nΩ9
Written guideline on distance between beds 0/5 (0%) 1/20 (5%) 2/8 (25%) 0.19
Written guideline on the use of antibiotics 1/4 (25%) 4/20 (20%) 2/9 (22%) 1.00
Regular rounds with infectious disease specialist 4/5 (80%) 20/20 (100%) 9/9 (100%) 0.15
Rounds with ID-specialist at least 5 days/week 0/5 (0%) 9/20 (45%) 6/9 (67%) 0.07
Hand disinfection, bedside § 4/5 (80%) 18/20 (90%) 7/9 (78%) 0.51
Report on antibiotic usage at least once a year 3/4 (75%) 16/18 (90%) 7/8 (88%) 0.76
Report on antibiotic usage at least every 3 months 2/4 (50%) 10/18 (56%) 5/8 (63%) 1.00
Report on bacterial species and drug resistance 2/5 (40%) 3/17 (18%) 1/6 (17%) 0.68
at least once a year
*Postoperative patients were included in some units, leading to a large number of admissions and short mean lengths of stay.
† P-values refer to comparisons between intensive care unit (ICU) categories.
‡ Correlated with total antibiotic usage (PΩ0.03, see text).
§ Negatively correlated with total antibiotic usage (PΩ0.05, see text). DDD 1000 , defined daily doses per 1000 occupied bed days. The number
of units (n) varies as a result of missing values. Unless otherwise stated the ICU characteristics did not correlate with antibiotic consumption.
tibed rooms ranged from 60 cm to 300 cm (22 ICUs).
Devices for hand-disinfection were available at the
bedside in 28/33 (85%) ICUs, with no significant difference
between the type of ICU (Table 1). The median
consumption of hand disinfectant was 104 l/1000 occupied
bed days (range 29–158 l, nΩ10 ICUs).
Twenty-one percent (7/33) of the ICUs had written
guidelines regarding use of antibiotics within the unit
(Table 1). The intensivist was in charge of decisions
regarding prescriptions of antibiotics in 18/33 (55%)
of the units, and the decision was documented in the
patient files in most of the units (32/34). Forty-four
percent of the ICUs (15/34) had regular rounds with
an infectious disease specialist (at least 5 days a week),
particularly in larger units (PΩ0.07), while 1/34 units
had no such regular rounds. We were unable to identify
any association between frequent rounds by an infectious
disease specialist and presence of bedside
hand-disinfection devices (PΩ0.62).
Antibiotic consumption
The quantity of antibiotics delivered was reported to
57% (17/30) of the ICUs at least every 3 months; only
4/30 units received no such information at all. Total
consumption of antibiotics varied up to fourfold between
the units but without difference between the
ICU categories or relationship to illness severity
scores (Table 1, Fig. 1).
Intensive care units with many admissions or short
mean lengths of stay had a usage of antibiotics that
was significantly lower than the median consumption
(PΩ0.01 and PΩ0.03, respectively; Table 1). Antibiotic
usage in units lacking devices for hand antisepsis at
the bedside was on average 1.6-fold higher than the
median antibiotic consumption in units with such
bedside devices (PΩ0.05).
Cephalosporins were the most frequently used
group of antibiotics (median 26% of the total consumption,
Fig. 2), but with considerable variation between
the ICUs with regard to usage (173.3–640.4
Fig.1. Total consumption of antibiotics at individual intensive care
units (ICUs). DDD 1000 , defined daily doses per 1000 occupied bed
days. The ICUs are identified by a random two-letter sequence. The
horizontal line represents the median value.
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DDD 1000 ) and the proportion of different generations
of cephalosporins (Fig. 3). The use of isoxazolyl penicillins
varied considerably (range 24–1271 DDD 1000 )
and was associated with a high total consumption of
antibiotics (rank correlation between use of isoxalyl
penicillins and total use of antibiotics: 0.57, PΩ0.001).
Whereas the consumption of most classes of drugs
did not differ between the ICU categories, the median
use of carbapenems was lower in the local hospitals
compared with county and regional hospitals (58, 110
and 143 DDD/1000 occupied bed days, respectively,
PΩ0.05; Fig. 4). In the ICUs with a specialist in infectious
diseases responsible for antibiotic treatment
only, the use of glycopeptides differed from that in
the other units (median 11 vs. 26 DDD 1000 , PΩ0.02).
Microbiology and antibiotic resistance
The median number of positive cultures normalized
per 1000 occupied bed days was 11.4 (range 2.6–19.2)
with no significant difference between the type of unit
or association and the presence or absence of an infectious
disease specialist. There was no difference in the
number of normalized positive cultures and the presence
or lack of bedside disinfection devices (PΩ0.41).
We were also unable to establish any relationship between
the consumption of hand disinfectant and the
number of normalized positive cultures (rank correlationΩ0.33,
PΩ0.38). All responding units received
preliminary information regarding bacterial growth in
blood cultures, while 74% of the ICUs received such
data also for other specimens. Feedback at the local
level on patterns of bacterial resistance to antibiotics
was provided at least annually by the microbiology
laboratory to 6/28 of the ICUs and at least every 3
months by 17/30 of the ICUs (Table 1).
Among the Enterobacter species (212 isolates), 34%
had decreased susceptibility to third generation cephalosporins
(cefotaxime or ceftazidime) and 63% of
213 isolates had decreased susceptibility to cefuroxime.
Of 710 Enterococcus species isolates from the regional
and county ICUs, 25% and 32%, respectively,
showed decreased susceptibility to ampicillin, but
only 17% of 60 bacterial isolates from the local hospitals
(difference between ICU category, PΩ0.02).
Among Pseudomonas aeruginosa, 26% showed decreased
susceptibility to imipenem, 11% to ciprofloxacin
and 11% to ceftazidime. Decreased susceptibility
to isoxazolylpenicillins was found in 70% of 1158 isolates
of coagulase-negative staphylococci, but in only
Fig.2. Proportion of total antimicrobial consumption per class of antibiotic.
DDD 1000 , defined daily doses per 1000 occupied bed days.
Fig.3. Consumption of individual cephalosporins in defined daily
doses per 1000 occupied bed days (DDD 1000 ) in each intensive care
unit (ICU). Loracarbef and cefadroxil were not included because they
were used infrequently and in few ICUs.
Fig.4. Median consumption of antimicrobials in defined daily doses
per 1000 occupied bed days (DDD 1000 ) in different categories of intensive
care unit. The consumption of carbapenems was significantly
lower in local ICUs compared with county and regional ICUs
(P0.05).
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1% of 627 isolates of Staphylococcus aureus (classified
as MRSA). Vancomycin resistance was not found in
staphylococci (248 isolates) and only one of 718 bacterial
isolates of enterococci (0.1%).
Discussion
This study combines data collected and accumulated
in a prospective manner within hospital pharmacies
and microbiology laboratories with answers to a questionnaire.
Responses were received from a cross-section
of Swedish adult ICUs covering approximately
70% of the population. There was a relative lack of
data from smaller units in local hospitals (10 out of
33) and tertiary care units in regional hospitals (10 out
of 22). As the data from most of the ICUs of the
county hospitals were collected (18 out of 23) we believe
that the findings mirrored conditions in Swedish
adult general ICUs during 1999 reasonably well.
Barely 50% of the responding ICUs used illness severity
scoring systems to define their case-mix. However,
the description of case-mix was probably even
less complete, as admissions to local hospitals typically
include coronary care and postoperative care patients
not routinely scored with any illness severity
scoring system. To partly circumvent the problem of
potentially large differences in case-mix between the
ICUs we aggregated the data per hospital category,
assuming that the case-mix remained fairly similar
within each category.
Nonetheless, it is possible that significant differences
in admission patterns within the same hospital
category contributed to the large difference in consumption
of antibiotics. The importance of specific admission
patterns is highlighted by the finding that
cardiothoracic ICUs were among the highest consumers
of antibiotics per 1000 occupied bed days.
When analyzed in more detail this resulted from the
large consumption of isoxazolyl penicillins, which are
given routinely postoperatively, and short lengths of
stay.
Most Swedish hospital pharmacies rely on computerized
systems to keep track of the delivery of drugs
as part of a reimbursement system within the local
hospital. Pharmaceutical products, including antibiotics,
are paid for by the local ICU, making disposal
of unused drugs a rare incident. Two potentially more
serious errors might be the occasional local setting in
which antibiotics were administered in the unit but
not primarily paid by the ICU, and the case in which
the ICU was responsible for the cost of antibiotics
used outside the unit. Because these events are rare
we believe that deliveries of antibiotics to the ICU ac-
ceptably mirror the consumption within the unit.
Comparison of consumption of antibiotics between
ICUs was facilitated by the use of DDD corrected for
occupied bed days. This measure depends heavily on
the calculation of occupied bed days, which in this
study was defined as the sum of length of stay (in
hours and minutes) of all admissions during 1999.
While DDD per 1000 occupied bed days (DDD 1000 )is
a reasonable index of antibiotic use within an ICU (8)
it does not provide any data on the prevalence of patients
receiving the antibiotics.
The specimens collected for cultures were taken at
the discretion of clinicians attending the ICU. It was
beyond the purpose of this work to determine
whether the isolates caused infection or only reflected
colonization of the critically ill. Decreased susceptibility
to antibiotics was defined as the sum of isolates
with intermediate susceptibility or resistance to antibiotics.
Although this avoids the risk of underestimating
the emergence of isolates with moderately reduced
sensitivity, it complicates a comparison with
other studies.
The most striking finding of this study of Swedish
adult ICUs was the up to fourfold difference between
the units in antibiotic consumption per occupied bed
day. While we were able to identify some ICU characteristics
that were associated with less antibiotic use
there was surprisingly no obvious association between
total antibiotic consumption and ICU category
or case-mix of admissions based on APACHE II
scores. Such a relationship could have been concealed
because we had difficulties in obtaining a satisfactory
picture of the case-mix from individual units. However,
the results are in agreement with the notion that
factors other than patient-related factors determine
the use of antibiotics (6). The total consumption of
antibiotics was high and showed that intensive care
patients were constantly treated with, on average, one
antibiotic or more. Yet, few of the ICUs had formal
guidelines regarding the use of antibiotics, and feedback
to clinicians from microbiologists regarding patterns
of antibiotic resistance was poor.
As selective decontamination of the digestive tract
was not used by any ICU in this study this cannot
account for the large differences. A host of other possibilities
exist, one important such explanation being
differences in case-mix not reflected by APACHE II
scores. Particularly, single-disease tertiary ICUs could
be expected to demonstrate specific patterns of consumption.
In agreement with this we noted a relatively
high consumption of antibiotics in cardio-thoracic
ICUs. We believe this to be in part due to the
routine use of perioperative antibiotics, as touched
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upon previously in this discussion, and admissions
typically having short lengths of stay. The reason for
the up to fourfold differences in overall consumption
between county hospitals was more difficult to understand.
Relationships with a set of diverse clinical practices
and hygiene control measures were sought, but, in
contrast to preliminary reports from the European
Strategy for Antibiotic Prophylaxis (ESAP, 13), we
were unable to establish any association between
these selected practice parameters and antibiotic consumption
except for a higher consumption in the
ICUs without bedside devices for hand disinfection.
The ESAP also found considerable heterogeneity in
the use of antibiotics in 21 European ICUs of six European
countries. In addition, that study observed that
the prescription of antibiotics was less when approval
was needed from a senior physician/microbiologist
and when a list of restricted compounds was defined.
Restricted compounds were defined as third and
fourth generation cephalosporins, ticarcillin-clavulanate,
piperacillin-tazobactam, carbapenems, amikacin,
fluoroquinolones and glycopeptides. Increased consumption
of these antibiotics were, in the ESAP study,
associated with surveillance of colonization in the
ICU and with sponsoring of meetings and other PR
activities by the pharmaceutical industry, suggesting
that factors other than patient-related factors determine
the use and choice of antibiotic therapy.
Cephalosporins were the most frequently administered
antibiotics in European ICUs in the early 1990s,
as shown in the EPIC study (14). This was still true in
the present cohort of ICUs with a median of 26% of
DDD 1000 being cephalosporins, although the percentage
for individual units ranged from 13% to 41%.
Such high consumption may be a matter of concern,
as evidence accumulates that cephalosporin usage is
an important determinant of selection and propagation
of multiply resistant micro-organisms (15,16).
The proportion between different cephalosporins
varied in our study but few units used anything other
than second and third generation compounds. Although
controversial, recent data suggest that fourth
generation cephalosporins are less conducive to the
development of bacterial multiresistance (17–19).
The use of carbapenems has increased during the last
decade in Swedish ICUs (10). In the present work carbapenems
accounted for 9% of total antibiotic consumption
measured as DDD, with larger use in county
and regional ICUs. An emergence of resistance to carbapenems
has been noted among isolates of
Pseudomonas aeruginosa in association with such increased
use (20). We found that 26% of Pseudomonas
aeruginosa isolates demonstrated intermediate susceptibility
or were resistant to imipenem. An additional
problem with the increased use of carbapenem is selection
of Stenotrophomonas maltophilia in ICU patients.
While alarming, P. aeruginosa and S. maltophilia were
only found in a small proportion (4% and 2%, respectively)
of all positive cultures in the present work.
The consumption of glycopeptides was low in comparison
with a recent French study (21). Units depending
on a specialist in infectious diseases for the
prescription of antibiotics had a generally lower use
of glycopeptides, which might be as a result of the
awareness among specialists in infectious diseases of
the need for restricted glycopeptide usage. Furthermore,
the low glycopeptide consumption can be explained
by the very low (1%) prevalence of methicillin-resistant
Staphylococci aureus (MRSA) in Swedish
ICUs, which is also the reason for the comparably
high (15%) isoxazolylpenicillin consumption in the
present cohort of ICUs.
Clinically significant resistance to antibiotics was
found among Enterobacter spp. with decreased sensitivity
to second and third generation cephalosporins.
This might explain the increased treatment with carbapenems
and it suggests that use of second and third
generation cephalosporins should be reduced in
Swedish ICUs.
Failure to use basic infection control techniques with
isolation precautions have been shown repeatedly to be
associated with the spread of nosocomial infections
within intensive care environments. While most ICUs
had one or two single bedrooms, a few units lacked
such facilities in agreement with a trend noted during
the last decade in Sweden (22). Intensive care unit beds
are typically spaced wide apart, as indicated by the
long median distances between beds in this study.
However, in a couple of ICUs the distances were sometimes
most likely too short to allow for efficient barrier
nursing. Because hand hygiene remains the most important
measure to prevent the transmission of microorganisms
(23) a link was sought between the number
of bedside devices for hand antisepsis, frequency of
clinical infection and consumption of antibiotics. There
was a lack of relationship between positive cultures
and the availability or consumption of hand disinfectant.
Among numerous possibilities this may indicate
that the frequency of positive cultures per occupied bed
days was a poor surrogate for a clinically significant infection.
However, we noted an association between
large antibiotic consumption and a lack of devices for
hand disinfection at the bedside. This is one of the relationships
found in the current work that needs to be
assessed carefully in prospectively designed studies
1080

efore a conclusive judgment of a cause-effect relationship
can be made.
The heterogeneity in total consumption of antibiotics
normalized per occupied bed days suggest that the prescription
and use of antibiotics can be improved. Optimization
of prophylaxis and the choice and duration
of empiric therapy remain critical goals to reduce antibiotic
pressure within ICUs. Although this is typically
achieved by having regularly updated written guidelines
and feed-back to all physicians, only 20% of the
ICUs in the present study had such formal policies.
While there is a lack of studies of optimal antibiotic
strategies for preventing the emergence of bacterial resistance,
there is consensus that knowledge of trends in
usage and costs coupled with insights in local patterns
of bacterial resistance are steps toward the prevention
and control of emerging bacterial resistance (6). Hence,
feedback on the results of this work was provided
through the internet to all ICUs and their serving partners.
We believe that in establishing such a system to
monitor the use of antibiotics and occurrence of bacterial
resistance, some of the strategic goals to prevent
and control the emergence of antimicrobial-resistant
micro-organisms may be achieved. Confirmation of
this belief will require continuing efforts in this field
with recurrent surveys and monitoring of local prescription
practices and bacterial resistance.
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Address:
Sten Walther, MD, PhD
Department of Cardiothoracic Anesthesia and Intensive Care
University Hospital
SE-581 85 Linköping
Sweden
e-mail: sten.walther/lio.se
1081