Epidemiology of Healthcare-Associated Drug-Resistant Gram Negative Bacilli
PI: Lisa Maragakis, M.D.
Sponsor: CDC

Antimicrobial-resistant gram negative bacilli (GNB) are emerging pathogens that pose a severe threat to patients in healthcare settings.  In particular, Acinetobacter baumannii and Pseudomonas aeruginosa cause healthcare-associated infections including bacteremia, meningitis, urinary tract infections, pneumonia, and wound infections.  Healthcare-associated infections with resistant GNB led to increased morbidity and mortality for patients and dramatically increase healthcare costs.  Antimicrobial resistance greatly limits therapeutic options for patients infected with these organisms, especially when there is resistance to the carbapenem class of antibiotics.  Most reports of highly resitant GNB in the literature involve outbreaks in the acute care setting.  Few studies address the incidence and prevalence of these organisms in other levels of care.  The first aim of our study is to determine the incidence and prevalence or these organisms in other levels of care.  The first aim of our study is to determine the incidence and prevalence of antimicrobial-resitant Acinetobacter and Pseudomonas in the Johns Hopkins Hospital, the Johns Hopkins Bayview Medical Center, the Bayview Gerontology Center, and the Howard County General Hospital.  These institutions represent healthcare in the acute-care, community hospital, and long-term care settings.  We will further define the epidemiology of these organisms by gathering descriptive data on the patients who are infected or colonized with MDR Acinetobacter or Pseudomonas and on the participating institutions.  Our preliminary data show that strians of resistant Acinetobacter the the Johns Hopkins Hosptial match strains from other healthcare facilities in Baltimore and that prior residence in a long-term care facility was a significant risk fator for acquisition of the organism in the hospital.  We hypothesize that healthcare-associated transmission of antimicrobial-resistant GNB occurs not only among patients at a single insitution, but among multiple healthcare insitutions in a community.  The second aim of our study is to use molecular strain typing by pulsed-field gel elctrophoresis (PFGE) to characterize the stains of antimicrobial-resitant Acinetobacter and Pseudomonas that coloize and infect the patients in the four participating Hopkins sites and to correlate this information with the estent of patient movement between institutions.  These studies are significant because antimicrobial-resitant GNB are a growing threat to patients and are extermely difficult to control.  A better understanding of their epidemiology is needed in order to design effective prevention strategies.

For more information on this study please email or contact Lisa Maragakis, M.D. at (410) 955-8384, or Kathleen Speck or Meg Gifford at (410) 614-6206.