Studying Methicillin-Resistant Staphylococcus Aureus Acquisition and Colonization in Healthcare Workers (MACH Study)
PI: Trish M. Perl, M.D., M.Sc.
Sponsor: Requesting Funding

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major pathogen in our hospitals and increasingly in our communities today.  Staphylococcus aureus is the  leading cause of healthcare associated infections, and MRSA accounts for 25-60% of isolates in hospitals, approaching 70% for intensive care units (ICU).  From both infection control and patient safety perspectives, this is extremely important.  Additionally, the emergence of community-acquired MRSA (ca-MRSA) has become a significant problem.  In the late 1990s, reports emerged of MRSA causing a severe sepsis syndrome, in patients who had no risk factors for nosocomially-acquired MRSA.  In contrast to nosocomially-acquired MRSA, ca-MRSA is often susceptible to many other non-beta -lactam antimicrobials such as clindamycin, trimethoprim-sulfamethoxazole (TMP-SMX), and gentamicin.  It has been further characterized by the presence of a type IV SCCmec cassette and virulence factors such as enterotoxin H, superantigens, and Panton-Valentine leukocidin (PVL). The rise in ca-MRSA poses new problems in terms of infection control, patient safety, and public health. The epidemiology of ca-MRSA is unknown at this time.  More information is needed to be able to adequately protect our health care workers and patients from this potential threat.

This is a prospective observational study in which housestaff and nursing staff will initially be screened for MRSA carriage, and successively screened for colonization at monthly intervals to assess for acquisition.  All medicine and pediatric housestaff will be asked to participate in the study.  In addition, nurses assigned to the medical intensive care unit (MICU) and nurses and clinical associates on Jefferson 3 will also be asked to participate.

Our research aims are:

• Determine the rate of colonization and incidence of MRSA acquisition among HCW
• For the housestaff, determine if incidence correlates with their clinical rotation
• Determine patterns of MRSA colonization (persistent, intermittent, or none) for the study population
• Determine if MRSA acquisition correlates with the clinical service of housestaff
• Determine prevalence of ca-MRSA among carriers of MRSA by molecular techniques, such as PVL gene assay
• Survey health care workers to assess for risk factors for MRSA colonization and whether any were diagnosed with MRSA-related infection during the study timeframe.

For information about this study e-mail Cecilia Johnston, M.D. or Amy Banowetz.