Approximately 400 California hospitals report healthcare-associated infection data to the California Department of Public Health via the National Healthcare Safety Network. When reporting central line-associated bloodstream infections (CLABSIs), hospitals are required to indicate the associated pathogen(s) and select antimicrobial susceptibility test results.
CLABSI pathogens reported by California hospitals during the reporting years of 2011-2014 were analyzed. Annual and 4-year, pooled non-susceptibility percentages were calculated for select bacterial species with clinically relevant antimicrobial resistance potential. Four-year trends were assessed with log binomial regression. All analyses were completed with SAS, version 9.3.
The pooled non-susceptibility percentage to oxacillin/methicillin among S. aureus isolates was 44.9% (95% CI: 42.4%, 47.4%); four-year trend analyses revealed a decrease (-9.4%, 95% CI: -15.4%, -2.9%) in non-susceptibility to oxacillin/methicillin over this period. The pooled non-susceptibility percentage of Klebsiella pneumoniae/oxytoca isolates to carbapenems was 14.3% (95% CI: 11.8%, 16.9%), with an increase in non-susceptibility to carbapenems over this time period (13.3%, 95% CI: -2.9%, 32.2%). The pooled non-susceptibility percentage for E. coli isolates to a combination of at least 3 antimicrobial agents from 5 classes (cephalosporins, fluoroquinolones, aminoglycosides, carbapenems, piperacillin/tazobactam) was 18.8% (95% CI: 16.3%, 21.4%), with an increasing trend (12.9%, 95% CI: -0.2%, 27.9%) of non-susceptibility over this period.
A significant decrease in oxacillin/methicillin non-susceptible S. aureus isolates was observed during 2011-2014. Although not statistically significant, increases in non-susceptible Klebsiella spp. isolates and E. coli isolates were also observed during this period. Monitoring antimicrobial susceptibility trends among pathogens associated with CLABSIs provides a surrogate measure of antimicrobial resistance in California hospitals. These data can be used to inform state-wide prevention efforts targeting antimicrobial use and resistance.