Comycin, Daptomycin 27 DM-HTN-RD-OSA CABG 3.1 weeks 5.4 weeks MRSA No growth N N 3B 5 3A Not shown 6 7Table 1. Demographic characteristics of patients (n = 9) and SWI status.SubjectsSWIAgeSWYesSWYesSWYesSWYesSWYesSWNoSWYesSWNoSWNoSternal Wound Biofilm following Cardiac SurgeryM, male, F, female; AKI, acute kidney disease; BMI, body mass index, CAD, coronary artery disease; CGH, coronary heart disease; DM, diabetes mellitus; END, endocarditis; GERD, gastro esophageal reflux disease; HTN, hypertension; HTN- P, Homotaurine pulmonary hypertension; HLD, hyperlipidemia; RD, renal dysfunction; COPD, chronic obstructive pulmonary disease; PVD, peripheral vascular disease; OSA, obstructive sleep apnea; RHD, rheumatic heart disease; CABG, coronary artery bypass graft; MVR, mitral valve replacement; LVAD, left ventricular assisted device; PM, pace maker; RV, right ventricle; N, negative; MSSA, Methicillin-sensitive Staphylococcus aureus; MRSA, Methicillin-resistant Staphylococcus aureus; SVT, supraventricular tachycardia. doi:10.1371/journal.pone.0070360.tSternal Wound Biofilm following Cardiac SurgeryFigure 2. MRSA Strain USA300 biofilm exhibits enhanced tolerance to tobramycin when grown as a biofilm on surgical wires. USA300 was used to inoculate in vitro wells containing sections of wire. Planktonic bacteria and wire-associated biofilms were challenged with 10 ug/ml of tobramycin for 2 hours. Bacteria tolerant to antibiotic challenge were enumerated using viability plating and compared to untreated parallel controls. Percent survivability of triplicate cultures is represented. nd, not detected, 23148522 ns, not significant. Data are mean6SD (n = 3), *p,0.05 compared to untreated planktonic (Mann Whitney test). doi:10.1371/journal.pone.0070360.gversus planktonic bacteria. After 2-h of challenge, tobramycin failed to kill wire-associated bacteria but reduced the planktonic load greater than five-log (Fig. 2). For the clinical study, nine patients were recruited. Three of the nine patients (control non SWI) had a cardiac surgery procedure previously and were scheduled for a second surgical procedure in which they underwent re-sternotomy. The sternotomy wound sites in the three patients were intact with an old scar and no signs of infection were noted. In the test arm, remaining six patients had deep sternal wound infection (SWI) which complicated their cardiac surgery and were therefore scheduled for a sternal debridement procedure (SWI group). These wounds were initially classified as infected by the physician AVP biological activity providing care using standard clinical criteria including systemic leukocytosis/fever and localized signs of infection including erythema, necrosis, discharge, and failure of healing. The infection involved the skin, subcutaneous tissue, and extended to the sternum. The sternotomy wound site displayed signs of active infection with localized erythema, exudates, friable wound edges and sternal instability (Fig. 3A). The average interval between the cardiac surgery procedure and the debridement procedure was 2 to 12 weeks in which different classes of antibiotics were used to manage infection (Table 1). Wound cultures showed colonization with MSSA, MRSA in two and other four showed negative culture data. As an initial screening method, the debrided tissues taken from infected sternal wounds were stained using Gram staining. The staining showed patchy pattern of colonization with numerous Gram positive cocci. Some areas of the tissues showed extensive colonizat.Comycin, Daptomycin 27 DM-HTN-RD-OSA CABG 3.1 weeks 5.4 weeks MRSA No growth N N 3B 5 3A Not shown 6 7Table 1. Demographic characteristics of patients (n = 9) and SWI status.SubjectsSWIAgeSWYesSWYesSWYesSWYesSWYesSWNoSWYesSWNoSWNoSternal Wound Biofilm following Cardiac SurgeryM, male, F, female; AKI, acute kidney disease; BMI, body mass index, CAD, coronary artery disease; CGH, coronary heart disease; DM, diabetes mellitus; END, endocarditis; GERD, gastro esophageal reflux disease; HTN, hypertension; HTN- P, Pulmonary hypertension; HLD, hyperlipidemia; RD, renal dysfunction; COPD, chronic obstructive pulmonary disease; PVD, peripheral vascular disease; OSA, obstructive sleep apnea; RHD, rheumatic heart disease; CABG, coronary artery bypass graft; MVR, mitral valve replacement; LVAD, left ventricular assisted device; PM, pace maker; RV, right ventricle; N, negative; MSSA, Methicillin-sensitive Staphylococcus aureus; MRSA, Methicillin-resistant Staphylococcus aureus; SVT, supraventricular tachycardia. doi:10.1371/journal.pone.0070360.tSternal Wound Biofilm following Cardiac SurgeryFigure 2. MRSA Strain USA300 biofilm exhibits enhanced tolerance to tobramycin when grown as a biofilm on surgical wires. USA300 was used to inoculate in vitro wells containing sections of wire. Planktonic bacteria and wire-associated biofilms were challenged with 10 ug/ml of tobramycin for 2 hours. Bacteria tolerant to antibiotic challenge were enumerated using viability plating and compared to untreated parallel controls. Percent survivability of triplicate cultures is represented. nd, not detected, 23148522 ns, not significant. Data are mean6SD (n = 3), *p,0.05 compared to untreated planktonic (Mann Whitney test). doi:10.1371/journal.pone.0070360.gversus planktonic bacteria. After 2-h of challenge, tobramycin failed to kill wire-associated bacteria but reduced the planktonic load greater than five-log (Fig. 2). For the clinical study, nine patients were recruited. Three of the nine patients (control non SWI) had a cardiac surgery procedure previously and were scheduled for a second surgical procedure in which they underwent re-sternotomy. The sternotomy wound sites in the three patients were intact with an old scar and no signs of infection were noted. In the test arm, remaining six patients had deep sternal wound infection (SWI) which complicated their cardiac surgery and were therefore scheduled for a sternal debridement procedure (SWI group). These wounds were initially classified as infected by the physician providing care using standard clinical criteria including systemic leukocytosis/fever and localized signs of infection including erythema, necrosis, discharge, and failure of healing. The infection involved the skin, subcutaneous tissue, and extended to the sternum. The sternotomy wound site displayed signs of active infection with localized erythema, exudates, friable wound edges and sternal instability (Fig. 3A). The average interval between the cardiac surgery procedure and the debridement procedure was 2 to 12 weeks in which different classes of antibiotics were used to manage infection (Table 1). Wound cultures showed colonization with MSSA, MRSA in two and other four showed negative culture data. As an initial screening method, the debrided tissues taken from infected sternal wounds were stained using Gram staining. The staining showed patchy pattern of colonization with numerous Gram positive cocci. Some areas of the tissues showed extensive colonizat.
