Percent Resistance for Select Pathogens Reported with Central Line-Associated Bloodstream Infections to CDC's National Healthcare Safety Network, January 2008-June 2010

Background: Recent reports have documented decreases in the incidence of central line-associated bloodstream infections (CLABSIs) through prevention collaboratives and nationally. However, treatment of CLABSIs remains difficult due to antimicrobial resistant pathogens. National Healthcare Safety Network (NHSN) data can be used to evaluate trends in resistance among pathogens causing CLABSIs, and to assess potential differences between intensive care units (ICUs) and non-ICU locations.

Objective: To determine the prevalence of select resistant pathogens among CLABSIs reported to NHSN from January 2008 to June 2010.

Methods: We evaluated the pathogen-antimicrobial combinations (phenotypes) most frequently reported with CLABSIs to NHSN. Data from all adult and pediatric ICU and non-ICU locations in facilities that reported ≥1 CLABSI at any time from January 2008-June 2010 were included; neonatal ICUs were excluded. The total number tested and number resistant were pooled across facilities and percent resistance (resistant/tested) was calculated, by year and pooled across years. Generalized linear regression modeling was used to evaluate changes in percent resistance over time and to assess relative impact of CLABSIs reported from non-ICU locations. A subset analysis including only facilities that reported ≥1 CLABSI in each of the three years was performed; only findings consistent in the overall analysis and the subset analysis are reported.

Results: A total of 26,878 CLABSIs were reported from 1,392 facilities in 48 states, yielding 29,741 pathogens for evaluation. Overall, the proportion of pathogens reported from non-ICU locations increased from 29% (2008) to 43% (2010). The percent resistance did not change significantly over the three years for any of the phenotypes; therefore data are reported in aggregate for the entire period (Table). The proportion of Staphylococcus aureus isolates resistant to methicillin (60.5% overall) was comparable in ICU and non-ICU settings, while the proportions of Klebsiella pneumoniae isolates resistant to extended-spectrum cephalosporins or carbapenems were significantly higher in ICUs (38.6% vs 26.9% and 17.3% vs 9.0%, respectively).

Conclusions: Percent resistance for the select phenotypes reported with CLABSIs to NHSN remained stable between January 2008 and June 2010. The proportions of multidrug-resistance among K. pneumoniae isolates causing CLABSIs from ICU settings are higher than previously reported from NHSN (2006-2007), suggesting these pathogens are becoming problematic in many facilities.