Assessment of Severe Extremity Wound Bioburden at the Time of Definitive Wound Closure or Coverage: Correlation with Subsequent Post-Closure Deep Wound Infection.


Principal Investigator: Dr. Michael Bosse

The primary objective of this study is to characterize the contemporary extremity wound “bioburden” at the time of definitive wound coverage or closure of severe extremity wounds employing new polymerase chain reaction PCR technology. We will also determine the relationship of subsequent infections to the initial bioburden screen as defined by both PCR technology and standard microbiology techniques.


Infection remains the most common and significant complication following severe fractures, with rates ranging from 25% – 40%. In contrast to significant advances made in extremity trauma care, the strategies that address the prevention of deep infection following severe open fracture wounds have remained constant for the past 20 years. Over the next decade, the treatment of the severe wound is expected to dramatically change. Local wound anti-microbial therapies employing biodegradable micro or nanospheres, ceramics or chitosan sponges will likely replace systemic therapy. These local antibiotic treatments might be potentiated by combining them with biofilm disbursing agents. However, the evolution of therapy to the local level requires a better understanding of the bioburden profile at the time of wound closure or coverage, and the impact, if any, of systemic and local antibiotics on the prevention of later infection.


At the present time, standard microbiology techniques are considered unreliable by most surgeons and, therefore, do not influence patient care decisions. Rather, antibiotics are selected to prevent infection without actually knowing the pathogen profile of the individual patient’s wound. If a deep infection develops, deep cultures are obtained and systemic therapy is provided based on the pathogen’s sensitivity profile. The addition of polymerase chain reaction (PCR) techniques to the wound bioburden analysis could enhance our ability to define the wound bioburden and the relationship of subsequent infections to the initial bioburden screen. The IBIS T5000 is a new generation rapid sequencing PCR technology ideally suited to the identification of wound bioburden.


The BIOBURDEN study will use this new generation of PCR technology to characterize the contemporary extremity wound “bioburden” at the time of definitive wound coverage or closure. We will prospectively collect wound samples from 600 lower extremity injuries at the time of wound closure, and analyze these samples for wound bacterial bioburden using the Ibis T5000 Biosensor System PCR technology. In addition, standard microbiology laboratory data and antibiotic use data will be collected at this time. These patients will then be followed for up to one year to collect tissue samples at the time of follow up surgical procedures and ascertain the onset of surgical site infections. These data will be used to assess the roles of baseline wound flora and antibiotic regimens on the later selection and antibiotic resistance profiles of the pathogens in the infected wounds.


This study is partially funded by the DOD OETRP METRC Consortium Award (W81XWH-09-2-0108).