Healthcare-associated bloodstream infections (BSI)
are associated with high mortality and morbidity, and increase duration
of hospitalization of patients substantially [1]. Vascular access,
especially central lines, is responsible for almost 60% of these
infections, [2]. Clear definitions for central line-associated
bloodstream infections (CLABSI) and their surveillance using standard
protocols is necessary, as correct diagnosis can avoid indiscriminate
removal of central line if the sepsis is not related to central line. In
developing countries, situation of CLABSI has not been systematically
analyzed [3]. In a previous study done in our Pediatric intensive care
unit (PICU), the incidence density of catheter-related blood stream
infection was 8.3/1000 patient days [4]. In developed countries, zero
CLABSI rates are considered as the standard of healthcare, and are an
important parameter for accreditation process of a healthcare facility.
We carried out the surveillance of CLABSI in our PICU
[5], and aimed to determine the risk factors and bacterial profile of
CLABSI.
Methods
This prospective cohort study was conducted in PICU
of All India Institute of Medical Sciences, New Delhi, for a period of
1.5 years (August 2011 to January 2013). Ethical clearance was obtained
from Institutional Ethics Committee.
Children, who stayed in PICU for more than 48 hours
and had no infection incubating at the time of admission, were included
in the study. The definition of CLABSI, their incidence density and
antimicrobial profile has been published elsewhere [5]. The definition
for CLABSI was based on CDC criteria [6], and incidence density was
calculated as episodes of CLABSI per 1000 central line days.Central-line
days were calculated by daily count of enrolled patients on central
line, admitted in PICU.
All children on central line were monitored. Type of
central line inserted, frequency of access/day [for drugs, total
parenteral nutrition(TPN), gastric acid blockers, blood products] was
noted.
Statistical analysis: Multiple parameters to
determine risk factors associated with CLABSI were analyzed, which
included the type of central line inserted, frequency of access/day and
the affect of receiving various infusates through the central line.Data
were managed on MS Excel and analyzed using Stata software, version 7.0
(Stata Corp., College Station, TX). Statistical significance between
morbidity and mortality parameters was assessed by Two-sample Wilcoxon
rank sum (Mann-Whitney) test and by Pearson chi-square test.
Results
During the study, 349 patients were enrolled.
Nineteen developed BSI, of which 13 (68.4%) had CLABSI and 6 (31.6%)
secondary BSI. Central line was placed in 265 (75.9%) patients (172
males) in PICU. Of these, 129 (48.7%) had triple lumen, 117 (44.1%)
single lumen, 15 (5.7%) PICC line and 4 (1.5%) had umbilical catheters.
Type of central line inserted was not related to development of CLABSI (P=
0.533).
Majority (55.8%) of the patients were <2 years of
age, 31.6% were in the age group of 5-15 years and 12.6% were 2-5 years.
Most common presentation/systems involved in patients who were put on
central line were respiratory (28.7%), CNS (15%), cardiopulmonary
(11.3%), sepsis/shock (10.2%), renal (8.3%), metabolic disorders(6.8%).
Less commonly, gastrointestinal tract involvement (5.7%), blood
disorders (3.0%), autoimmune diseases (2.3%) were noted.
Central-lines were changed in 66 (24.9%) patients.
Changing central line was associated with higher incidence of CLABSI (P=0.024),
especially with triple lumen CL change (P= 0.017) (Table
I).
TABLE I Relationship Between Central Line-associated Bloodstream Infections and Change of Central Line
Central line
|
Total
|
Blood stream
infections, No. (%) |
Unchanged |
199 |
6 (3.0%) |
Triple lumen |
105 |
3 (2.9%) |
Single lumen |
77 |
3 (3.9%) |
Others |
17 |
0 |
Changed* |
66 |
7 |
Triple lumen |
24 |
5 (20.8%) |
Single lumen |
40 |
1 (2.5%) |
Others |
2 |
1 |
Number of times changed* |
|
|
Once |
40 |
5 (12.5%) |
Twice |
23 |
2 (8.7%) |
Thrice |
2 |
0 |
Six times |
1 |
0 |
*P<0.05. |
Majority (89.8%, n=238) of central lines were
inserted in femoral vein; others in subclavian, brachial and umbilical
vein. Site of central line insertion and development of CLABSI showed no
relation (P =0.761). Also, no higher risk of CLABSI incidence was
found in patients who received total parenteral nutrition (166 vs
99) or gastric acid blockers (167 vs 98).
Mean number of times CL was accessed/day in patients
who developed CLABSI was much higher (18.46 vs. 11.70; P<0.001).
Mean length of stay of patients with CLABSI was longer (27.30 vs.
8.76 d ) (P<0.001). Also, CLABSI was associated with
higher mortality of 38.5% (5/13) compared to 13.7% (46/336) in patients
without CLABSI.
In six patients with secondary BSI, lower respiratory
tract was primary site of infection for four episodes of BSI (2
Acinetobacter spp., 1 Pseudomonas spp. and 1 Klebsiella
spp.), and urinary tract for two (Candida spp.). Broncho-alveolar
lavage (BAL) and urine sample were taken for culture, respectively and
same isolates were later cultured from blood samples.
Predominance of gram negative pathogens was found in
our study. Klebsiella spp. caused 5 , Pseudomonas spp.
3 (23.1%), S.epidermidis 2, and Acinetobacter spp.,
Proteus spp. and Enterococcus faecium each caused
one episode of CLABSI. The antimicrobial susceptibility showed a high
percentage of multidrug resistant bacteria with gram negative bacteria
showing susceptibility to carbapenems and beta lactamase inhibitor
combi-nations,while gram positive being susceptible to vancomycin and
linezolid [5].
Discussion
In this study, we found that triple lumen central
line was the most common type of line used and femoral vein was the most
common site of central line insertion. We did not find any relationship
between these variables and CLABSI. Also, patients receiving TPN or
gastric acid blockers did not show higher risk of developing CLABSI.
Important risk factors associated with CLABSI were frequency of central
line access/day and changing triple lumen central line once or more.
Limitations of our study include a small study
population and short duration of the study. Catheter manipulation is a
known risk factor in development of catheter-related sepsis [7,8], as
chances of introducing patient’s own skin flora or transferring an
epidemic strain via hands of healthcare workers increases.
CDC recommends that central line should not be
removed on basis of fever alone and clinical judgment be applied [9].
Central line was unchanged in six CLABSI patients and managed using
systemic antimicrobial therapy. Of 66 patients, in whom central line was
changed (catheter blockage, local site infection or suspicion of a BSI),
7 consequently developed CLABSI (central line in place for >2 calendar
days).
Femoral vein is avoided in adults for central line
placements because of higher colonization rates and risk of deep-vein
thrombosis. But for pediatric population, CDC states "no recommendation
can be made for a preferred site of central line insertion" [9].
Most common causative pathogens for CLABSI in the US
are coagulase-negative staphylococci [10], S. aureus, enterococci,
and Candida spp. Gram negative bacilli account for 19% of CLABSIs
[11]. We found a predominance of gram-negative bacilli, similar to a
study done on nosocomial BSI in Chandigarh, India [12]. A previous study
done in our PICU also found 96.5% of bacterial isolates causing
healthcare-associated infections to be gram-negative bacteria [4]. Thus,
gram-negative bacill continue to dominate in developing countries where
infection control practices are suboptimal. Moreover, approximately 31%
of our isolates were nil-fermenters, which are now on the rise in
healthcare settings. Emerging multi-drug resistant gram-negative
bacteria are a major challenge in treatment of these infections, as also
seen in our study.
Although, our hospital does not have a written
antibiotic optimization policy, each department has antibiotic guidance
protocols based on the local data of culture positive cases. The
department of microbiology shares this data with the departments/units,
which is updated regularly based on the spectrum of infections and
antibiotic resistance pattern of organisms. Infection control nurse
takes regular rounds and conducts surveillance of healthcare associated
infections in various wards and ICU’s of the hospital.
CLABSI are preventable primary bacteremias. Based on
the present data, we suggest that the number of times the central line
is accessed should be minimized and that too under strict aseptic
precautions. Unnecessary change of line must be avoided and ongoing
surveillance and evidence based studies should support such decisions.
Healthcare workers should be educated about importance of hand hygiene
and full barrier precautions [13].
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