Literature Update - December 2009
Compiled by Dr Leon Worth, ID Physician
Catheter-related Bloodstream Infection: Taking a Look Beyond ICU
Catheter-related bloodstream infections are frequently monitored in intensive care units (ICUs). Mortality and increased healthcare costs
have been demonstrated within ICUs, and multi-modal strategies have therefore often been developed for prevention and risk-reduction in this
environment. Few studies have quantified the relative frequency of catheter-related bloodstream infections outside of the ICU environment.
Zingg W et al (J Hosp Infect 2009; 73:41-46) prospectively evaluated the hospital-wide epidemiology of
catheter-related bloodstream infections in a large Swiss tertiary care centre.
All adult hospitalised patients receiving a central venous catheter (CVC) between September 2006 and January 2007 were evaluated daily
and standardised definitions for catheter-related bloodstream infection were applied.
In total, 248 patients were studied, of whom 15 (6%) developed catheter-related bloodstream infection. Infections were most often due to
coagulase-negative staphylococci, enterococci and methicillin-resistant Staphylococcus aureus. Receipt of
parenteral nutrition, and higher length of hospital stay were associated with the development of catheter-related bloodstream infection.
Most CVC days (2203, 62%) occurred in non-ICU department. The overall CVC utilisation rate was 5.0 per 100 patient-days, but this differed
considerably between ICU and non-ICU patient populations, with rates of 29.8 and 4.6 per 100 patient-days, respectively. The incidence
densities for catheter-related bloodstream infections in ICU, internal medicine, non-abdominal surgery, and abdominal surgery were
4.91, 1.88, 2.38 and 7.65 episodes per 1000 CVC-days at risk, respectively. In the abdominal surgery department, higher Karnofsky indexes
were observed in patients, as well as longer hospital stays and frequent administration of parenteral nutrition.
Results of the single-centre study indicate that CVCs are widely used outside of the ICU, and that catheter-related bloodstream infections
are a frequent complication in these settings. The highest overall rate of infection was found in abdominal surgery – this seemingly high-risk
group requires further evaluation in deciding the hospital-wide scope of surveillance activities for catheter-related bloodstream infections.
Chlorhexidine Bathing and Reduction of Bloodstream Infections in a Long-term Acute Care Hospital
As a topical antiseptic, chlorhexidine has been shown in previous studies to reduce the rates of bloodstream infection when used for daily
bathing of patients in intensive care units (ICUs). A demonstrated benefit has not been reported in other less-acute settings. Munoz-Price
LS et al (Infect Control Hosp Epidemiol 2009; 30:1031-1035) therefore studied the impact of chlorhexidine
in preventing bloodstream infections at a long-term acute care hospital.
The study was performed between February 2006 and February 2008. A pre-intervention period (February-August 2006)
where patients received daily soap and water baths preceded an intervention period (September 2006-May 2007) where daily 2% chlorhexidine
baths were given to patients. A post-intervention period (June 2007-February 2008) followed, where a number of
products were used for cleaning, but no chlorhexidine was used. The incidence of central venous catheter (CVC)-associated bloodstream
infection and ventilator-associated pneumonia (VAP) were assessed during these defined study periods. Interrupted time-series analysis was
performed using the incidence densities for these infections.
During the 24 month study period, a total of 139 cases of CVC-associated bloodstream infection were identified. The average rate of these
infections was 9.5 cases per 1000 CVC days during the pre-intervention period, 3.8 cases per 1000 CVC days during the intervention period,
and 6.4 per 1000 CVC days in the post-intervention period. During the pre-intervention period, the monthly rates of CVC-associated bloodstream infection remained stable and during the intervention period the rates decreased 12% per month. No changes were observed in the incidence of VAP during the pre-intervention and intervention periods. Adverse reaction to chlorhexidine was not found to be a limiting factor; 3 of 405 patients had to discontinue chorhexidine application because of generalised redness/itching. These were all mild and reversible reactions.
One limitation of the study was the fact that regular supervision was required to ensure standardised product application, including the
avoidance of dilution of the chlorhexidine by use of additional water for bathing. Results of the current study are encouraging and
suggest that topical skin de-contamination may play an important role in reducing the risks of CVC-associated bloodstream infection in
non-ICU environments. The feasibility of this intervention in larger healthcare facilities must now be demonstrated.