First Evidence of Sternal Wound Biofilm following Cardiac Surgery

Abstract

Management of deep sternal wound infection (SWI), a serious complication after cardiac surgery with high morbidity and mortality incidence, requires invasive procedures such as, debridement with primary closure or myocutaneous flap reconstruction along with use of broad spectrum antibiotics. The purpose of this clinical series is to investigate the presence of biofilm in patients with deep SWI. A biofilm is a complex microbial community in which bacteria attach to a biological or non-biological surface and are embedded in a self-produced extracellular polymeric substance. Biofilm related infections represent a major clinical challenge due to their resistance to both host immune defenses and standard antimicrobial therapies. Candidates for this clinical series were patients scheduled for a debridement procedure of an infected sternal wound after a cardiac surgery. Six patients with SWI were recruited in the study. All cases had marked dehiscence of all layers of the wound down to the sternum with no signs of healing after receiving broad spectrum antibiotics post-surgery. After consenting patients, tissue and/or extracted stainless steel wires were collected during the debridement procedure. Debrided tissues examined by Gram stain showed large aggregations of Gram positive cocci. Immuno-fluorescent staining of the debrided tissues using a specific antibody against staphylococci demonstrated the presence of thick clumps of staphylococci colonizing the wound bed. Evaluation of tissue samples with scanning electron microscope (SEM) imaging showed three-dimensional aggregates of these cocci attached to the wound surface. More interestingly, SEM imaging of the extracted wires showed attachment of cocci aggregations to the wire metal surface. These observations along with the clinical presentation of the patients provide the first evidence that supports the presence of biofilm in such cases. Clinical introduction of the biofilm infection concept in deep SWI may advance the current management strategies from standard antimicrobial therapy to anti-biofilm strategy.

A Wireless Electroceutical Dressing Lowers Cost of Negative Pressure Wound Therapy

“…The bacterial burden in postoperative wounds is a major concern because it may necessitate repeated surgical interventions, longer hospital stay, and higher healthcare cost. 23 The use of a silver-coated polyurethane dressing (VAC GranuFoam Ò Silver Dressing; KCI) during NPWT is aimed at infection control. However, it is reported that such a dressing is not effective in delivering silver ions to the wound and most silver is removed by the suction force and found in the wound exudate.…”

A Formidable Foe Is Sabotaging Your Results: What You Should Know about Biofilms and Wound Healing

“…The same authors also demonstrated that biofilm contributes to wounds associated with mesh infections in the context of abdominal hernia repair [27]. Recently, Elgharably et al evaluated the role of biofilm in sternal wound infections occurring after median sternotomy [5] (see video). The authors prospectively enrolled 6 patients with sternal wound dehiscence and 3 patients without infectious complications having repeat sternotomy for elective cardiac surgery.…”

Clinical Biofilms: A Challenging Frontier in Wound Care

“…30 Elgharably et al provided the first direct evidence of biofilm involvement in human deep sternal wound infection. 49 It has been demonstrated that biofilm impairs key healing processes such as the inflammatory immune response, granulation tissue formation, and epithelialization. 5 Biofilm has been shown to tolerate antibiotics and topical antiseptics in isolation, although multimodal strategies to suppress biofilm were more effective.…”

“…Wound biofilm has been documented as emerging in acute wound drains within 2 h after surgery 36 in damaged tendons 37 and in chronic 1,2,33,34 and acute 1,49 wounds. However, there is still a need for further evidence-based knowledge in improving clinical wound or patient outcomes.…”

“…49 Biofilm presence means that stubborn communities of microorganisms are established that are tolerant to antibiotics, antiseptics, and inflammatory processes. Biofilm development has been shown to delay healing 15 and can lead to infection.…”