551. Clinical Predictors of Methicillin-Resistant Staphylococcus aureus Colonization on Admission
Session: Poster Abstract Session: MRSA Surveillance and Infection Prevention
Friday, October 21, 2011
Room: Poster Hall B1
  • Risk Stratification_Poster 2.pdf (218.7 kB)
  • Background: 

    Early recognition of methicillin-resistant Staphylococcus aureus (MRSA) colonization allows timely institution of infection control measures to prevent cross-transmission. 

    This study aims to evaluate clinical predictors of MRSA colonization of patients on admission.


    Our institution implemented universal screening for MRSA on admission since July 2010. We prospectively interviewed patients requiring admission at emergency department from September to October, 2010 using standard questionnaire.

    Data collection includes basic demographics, comorbidities, history of prior MRSA, hospitalization and antimicrobial use. Electronic records were also reviewed for prior MRSA status and antimicrobial use.

    MRSA screening is by swabbing nares, axilla, groin and wound for culture.

    We performed univariate and multivariate analysis of clinical variables predicting MRSA colonization on admission.


    1055 patients completed the questionnaires. Of these, 61 patients were screened positive for MRSA on admission.

    Patients with MRSA colonization on admission are more likely to be older, resident of nursing home, and had prior MRSA colonization, urinary catheter, nasogastric tube, hypertension, diabetes mellitus, skin disorder, wound, recent hospitalization and prior antimicrobial use.

    In multivariate analysis, independent predictors of MRSA colonization on admission are previous MRSA colonization within 6 months (Odds Ratio (OR) 15.76; 95% Confidence Interval (95% CI) 1.74 to 142.75, P = 0.014), prior antimicrobial use (OR 9.60; 95% CI 4.84 to 19.06, P <0.0001), nursing home resident (OR 5.33; 95% CI 2.23 to 12.73, P <0.0001), recent hospitalization within 3 months (OR 2.29; 95% CI 1.15 to 4.56, P = 0.019), diabetes mellitus (OR 2.21; 95% CI 1.11 to 4.41, P =0.024), presence of nasogastric tube (OR 5.27; 95% CI 1.11 - 25.07, P =0.037).


    Resident of nursing home, prior antimicrobial use, prior MRSA colonization within 6 months and recent hospitalization within 3 months, are strong independent predictors of MRSA colonization on admission. These clinical variables could be used to stratify risk of MRSA colonization on admission and allow pre-emptive isolation prior to availability of screening culture results.

    Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

    Say-Tat Ooi, MD1, Sze Cheng Lim, RN2, Yumin Chen, RN2, Florence Liong Cheu Chng, RN2 and Christopher George Willis, MD1, (1)General Medicine Department, Khoo Teck Puat Hospital, Singapore, Singapore, (2)Nursing Department, Khoo Teck Puat Hospital, Singapore, Singapore


    S. T. Ooi, None

    S. C. Lim, None

    Y. Chen, None

    F. L. C. Chng, None

    C. G. Willis, None

    Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.