Partners : PBIDI

Research

Research Team | Background | Publications | Findings | News

The most important current research of The Palm Beach Infectious Disease Institute (PBIDI) is designed to determine characteristics of invasive Methicillin-resistant Staphylococcus aureus (MRSA) to understand how the bacterium causes serious infection.

Research Team

Gordon Dickinson, M.D.
Division of Infectious Diseases, Department of Medicine, University of Miami Miller School of Medicine
Miami VA Healthcare System
Palm Beach Infectious Disease Institute

Susanne Hower, Ph.D.
Department of Microbiology and Immunology, University of Miami Miller School of Medicine

Istvan Krisko, M.D.
Palm Beach Infectious Disease Institute

Lisa R. W. Plano, M.D., Ph.D.
Departments of Pediatrics and Microbiology & Immunology, University of Miami Miller School of Medicine
Palm Beach Infectious Disease Institute

Background & Concept

Approximately one third of healthy humans will be colonized with Staphylococcus aureus (staph) bacteria at any given time, most likely on their skin or in their nose, without it causing harm. However, in some cases it can invade and cause severe infections of skin and soft tissues, sinuses, lungs, joints, bones and heart valves. Often, when these infections are acquired by compromised individuals, such as those in hospitals, they are costly and sometimes fatal. Serious infections caused by staph have been recognized throughout the antibiotic era, and although much has been learned about the epidemiology of this bacterial pathogen, efforts to prevent and treat the conditions caused by staph are not always successful.

There are multiple factors that govern why and when these bacteria turn into pathogens.

  • The organisms must contact a potential host. This is accomplished by colonization or exposure to a new organism from the local environment.
  • The host’s natural defenses must be curtailed for infection to occur.
  • The S. aureus must have the necessary “virulence factors” to establish these infections.

Not all S. aureus are alike and some are more likely to cause infection than others. These bacteria have the potential to carry a wide array of virulence factors that the bacteria can use to enhance colonization, invasion or infection.

Our ongoing work is driven by the assumptions that the opportunity for contact and possible subsequent infection of a healthy individual with S. aureus is similar for essentially all. Therefore, the distinct genetic background of the individual bacteria, the array of virulence factors an individual bacterium can produce, likely plays a key role in not only establishing infection, but determining what diseases it may cause and how serious an infection may be.

We hypothesized that, based upon the genetic background including which of the virulence factors a strain of S. aureus could produce, we can make assumptions about which organisms are more likely to actually cause infections, as opposed to establish harmless colonization in a healthy person.

Specifically, we are interested in the factors, both host and bacterial, that govern colonization and infection. These include the multiple factors that these bacteria may produce that help them evade the hosts’ immune response; what triggers the bacteria to make these “virulence” factors and how do they affect the outcome of infections.

Armed with the knowledge of the identity of the factors most likely to be associated with specific infections and, conversely, those most likely to be associated with a benign colonization, we can begin to make more informed medical decisions regarding patient care and treatment of a known colonized individual. We can also use this information in addressing risks for potential patients — normal individuals in the community who might be colonized, but are not infected, with an organisms identified as one associated with serious infections.

We are currently collecting and analyzing clinically relevant MRSA. The knowledge gained from the completion of these studies, including extensive comparisons with other large populations of bacteria collected from healthy uninfected individuals or the environment, will aid in determining the important factors associated with specific infections and understanding how they affect disease. These studies will not only give us insight into the disease process itself and the host response, but may also provide us with potential targets not previously known, for use in prevention or treatment.

Publications

PBIDI has been instrumental in supporting the ongoing analysis of regional MRSA causing serious infectious disease that were utilized as important clinical controls in the following published studies completed at The University of Miami Miller School of Medicine in collaboration with the Oceans and Human Health Center at the University of Miami Rosenstiel School.

Other Supported Projects

Findings

Community-Associated Methicillin Resistant Staphylococcus aureus in South Florida Hospital and Recreational Environments
Poster session: ASM 2014 – American Society for Microbiology 114th General Meeting, Boston, MA

In The News

Collaborative Studies Show Clear Link Between Human Bacteria and Ocean Environments
Two Miller School collaborative studies led by Lisa Plano, M.D., Ph.D., associate professor of pediatrics and microbiology and immunology, have shown a clear link between a common human bacterium and ocean environments. More