Antibiotic Resistance Threats in the United States, 2013 report

Technical Appendix
Carbapenem-Resistant Enterobacteriaceae
Multidrug-Resistant Acinetobacter
Fluconazole-Resistant Candida
Extended Spectrum Β-lactamase producing
Enterobacteriaceae (ESBLs)
Vancomycin-Resistant Enterococcus (VRE)
Multidrug-Resistant Pseudomonas aeruginosa
Methods
National estimates of the number of healthcare-associated infections
(HAIs) with Enterobacteriaceae, Pseudomonas aeruginosa, Candida,
Acinetobacter, or Enterococci were obtained from a 2011 survey of
11,282 patients in 183 hospitals in 10 different states, among whom
452 were identified with at least one HAI for a total of 504 HAIs (some
patients had >1 HAI).
Many assumptions were made in deriving national estimates, using
these 452 patients, and adjusting for age and length of stay using
the 2010 Nationwide Inpatient Sample (NIS), Healthcare Cost and
Utilization Project (HCUP), Agency for Healthcare Research and
Quality. For 2011, an estimated 647,985 patients had at least one HAI,
resulting in an estimated 721,854 HAIs. 1 481 pathogens were reported
among the 504 HAIs detected; 50 K. pneumonia or K. oxytoca (9.9%),
47 E. coli (9.3%), 46 Enterococci spp. (9.1%), 36 P. aeruginosa (7.1%), 34
Candida spp. (6.7%), 8 Acinetobacter spp. (1.6%). For each pathogen, the
pathogen-specific annual estimate was obtained by multiplying this
proportion (of all HAIs) by the national HAI estimate (721,854). Next,
the estimated no. of resistant infections was obtained by multiplying
the respective pathogen-specific national estimate by the proportion
of pathogens reported as non-susceptible to the antimicrobial
of interest from other CDC data systems. For Enterobacteriaceae,
Pseudomonas aeruginosa, Acinetobacter, and Enterococci this was CDC’s
National Healthcare Safety Network and includes the mean percent
non-susceptible across the device and procedure-associated HAIs
reported during 2009–2010 2 ; see individual fact sheets in this report
for percent resistance for each pathogen.
For Candida by the proportion of Candida species testing nonsusceptible
to fluconazole that were submitted to CDC for
confirmatory testing as part of the Emerging Infections Program
Surveillance of Candida bloodstream infections during 2008-2011. 3 In
this program a total of 2,675 Candida species isolates associated with
bloodstream infections were submitted as part of the EIP populationbased
surveillance in 2 US cities, azole resistance was identified in 165
cases, or 7%.
95