The Alarming Rise of CA-MRSA at UMass-Memorial Medical Center David M. Bebinger, M.D. Assistant Professor Division of Infectious Diseases UMass-Memorial Medical Center July 30, 2007

MRSA Epidemiology Study Participants   David M. Bebinger, MD   Richard T. Ellison III, MD   Ranjan Chowdhry, MD   Rose Erlichman, RN, BSN, CIC

MRSA Trends at UMMC

Study Objective To identify demographic features associated with acquisition of CA-MRSA as compared to acquisition of healthcare- associated (HCA) or nosocomially acquired (Noso) MRSA.

Methods  A retrospective record review of patients identified previously by the infection control department as being newly diagnosed with an infection or colonization with MRSA between October 1, 2003 and September 30,   All cases were evaluated by infection control practitioners and categorized as CA, HCA, or Noso.  Of 2920 patients meeting this inclusion criteria 879 were chosen for chart review

Total Number of New MRSA Cases TotalCAHCANoso Total

Information recorded from electronic record review:  Age  Sex  Race  Zip code  Culture site  Healthcare site  Amount of exposure to the UMass system Methods

Average Age of Patient by Year *includes neonatal infections CAHCA*NosoTotal Total P<0.0001

Average Age of Patient by Year

Percentage of Male Patients CAHCANosoTotal TOTAL

Percentage of Caucasian Patients CAHCANoso /8483/9082/ /7384/9075/ /7776/8481/85 Total73/8385/9383/91 % of total/Adjusted for unlisted race P<0.003

Ethnicity

MRSA Epidemiology Study Percentage of Cultures Obtained From Inpatient and Emergency Department By Year Inpatient Total Inpatient CA Inpatient HCA ED Total

Total #CAHCANoso Percentage of Cultures labeled “Wound”

Patients With Bacteremia by Year CAHCANosoTotal

Healthcare exposure: >15 days exposed to UMass System CAHCANoso

Healthcare exposure: >15 days exposed to UMass System

Healthcare exposure: <6 days exposed to UMass System CAHCANoso ALL67216 P<0.001 P<0.025

Healthcare exposure: <6 days exposed to UMass System

Antibiogram Data ErythroLevoClindaTMP/ SMX Tetra- cyclin CA HCA Noso All Indicates percentage of isolates sensitive to given agent

Antibiogram Data

A Caveat to Clindamycin Data  “Our lab does not correctly test for resistance to clindamycin. In order to do this properly you have to perform a D-test.”  Most Mec IV isolates are D-test negative Jennifer Daly, MD

The incidence of CA-MRSA at UMMMC now consistently exceeds the incidence of HCA-MRSA and Noso-MRSA. CA-MRSA patients are younger, more ethnically diverse, and are primarily presenting with skin and soft tissue infections. MRSA should now be considered a possible pathogen in ALL patients with possible S. aureus infections The decreasing level of prior contact with our healthcare system suggests that the strain is established in our community. Conclusions

Ramifications Current infection control practices are unlikely to contain the continued spread of MRSA – which will have major implications in both the overall approach to the management of patients with MRSA, as well as strategies to prevent healthcare associated illnesses such as surgical site infections Mec IV, USA 300 and USA 400 strains may have a fitness advantage above their ability to survive in the presence of beta-lactam antibiotics