The SHIELD Orange County Project: Multidrug-resistant Organism Prevalence in 21 Nursing Homes and Long-term Acute Care Facilities in Southern California

Clin Infect Dis. 2019 Oct 15;69(9):1566-1573. doi: 10.1093/cid/ciz119.


Background: Multidrug-resistant organisms (MDROs) spread between hospitals, nursing homes (NHs), and long-term acute care facilities (LTACs) via patient transfers. The Shared Healthcare Intervention to Eliminate Life-threatening Dissemination of MDROs in Orange County is a regional public health collaborative involving decolonization at 38 healthcare facilities selected based on their high degree of patient sharing. We report baseline MDRO prevalence in 21 NHs/LTACs.

Methods: A random sample of 50 adults for 21 NHs/LTACs (18 NHs, 3 LTACs) were screened for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), extended-spectrum β-lactamase-producing organisms (ESBL), and carbapenem-resistant Enterobacteriaceae (CRE) using nares, skin (axilla/groin), and peri-rectal swabs. Facility and resident characteristics associated with MDRO carriage were assessed using multivariable models clustering by person and facility.

Results: Prevalence of MDROs was 65% in NHs and 80% in LTACs. The most common MDROs in NHs were MRSA (42%) and ESBL (34%); in LTACs they were VRE (55%) and ESBL (38%). CRE prevalence was higher in facilities that manage ventilated LTAC patients and NH residents (8% vs <1%, P < .001). MDRO status was known for 18% of NH residents and 49% of LTAC patients. MDRO-colonized adults commonly harbored additional MDROs (54% MDRO+ NH residents and 62% MDRO+ LTACs patients). History of MRSA (odds ratio [OR] = 1.7; confidence interval [CI]: 1.2, 2.4; P = .004), VRE (OR = 2.1; CI: 1.2, 3.8; P = .01), ESBL (OR = 1.6; CI: 1.1, 2.3; P = .03), and diabetes (OR = 1.3; CI: 1.0, 1.7; P = .03) were associated with any MDRO carriage.

Conclusions: The majority of NH residents and LTAC patients harbor MDROs. MDRO status is frequently unknown to the facility. The high MDRO prevalence highlights the need for prevention efforts in NHs/LTACs as part of regional efforts to control MDRO spread.

Keywords: CRE; MRSA; chlorhexidine; decolonization; long term care; public health.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • California / epidemiology
  • Carbapenem-Resistant Enterobacteriaceae / pathogenicity
  • Chlorhexidine / therapeutic use
  • Drug Resistance, Multiple, Bacterial
  • Enterobacteriaceae Infections / epidemiology
  • Humans
  • Long-Term Care / statistics & numerical data*
  • Methicillin-Resistant Staphylococcus aureus / pathogenicity
  • Nursing Homes / statistics & numerical data*
  • Prevalence
  • Public Health
  • Staphylococcal Infections / epidemiology
  • Vancomycin-Resistant Enterococci / pathogenicity


  • Chlorhexidine