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Is the use of topical vancomycin to prevent mediastinitis after cardiac surgery justified?

2000; Elsevier BV; Volume: 119; Issue: 1 Linguagem: Inglês

10.1016/s0022-5223(00)70248-0

1097-685X

Reida El Oakley, Khalid Al Nimer, Emad Al Bukhari,

Antimicrobial Resistance in Staphylococcus

Patients undergoing cardiopulmonary bypass (CPB) are at substantial risk of acquiring infections because of the increased number of potential ports of entry of pathogens in the presence of CPB-induced impairment of immune responses.1El Oakley RM Wright JE Post-operative mediastinitis: classification and management.Ann Thorac Surg. 1996; 61: 1030-1036Abstract Full Text PDF PubMed Scopus (517) Google Scholar Despite regular use of prophylactic intravenous antibiotics, postoperative mediastinitis occurs in 0.4% to 5% of patients undergoing cardiac operations.1El Oakley RM Wright JE Post-operative mediastinitis: classification and management.Ann Thorac Surg. 1996; 61: 1030-1036Abstract Full Text PDF PubMed Scopus (517) Google Scholar This complication is associated with a 14% to 47% risk of in-hospital mortality.1El Oakley RM Wright JE Post-operative mediastinitis: classification and management.Ann Thorac Surg. 1996; 61: 1030-1036Abstract Full Text PDF PubMed Scopus (517) Google Scholar Gram-positive bacteria are the most common isolates from patients with mediastinitis; Staphylococcus aureus and Staphylococcus epidermidis are identified in 70% to 80% of cases.1El Oakley RM Wright JE Post-operative mediastinitis: classification and management.Ann Thorac Surg. 1996; 61: 1030-1036Abstract Full Text PDF PubMed Scopus (517) Google Scholar In a prospective randomized controlled study, Vander Salm and associates2Vander Salm TJ Okike ON Pasque MK et al.Reduction of sternal infection by application of topical vancomycin.J Thorac Cardiovasc Surg. 1989; 98: 618-622PubMed Google Scholar found that topical vancomycin applied during wound closure after median sternotomy was associated with a significant reduction in the rate of sternal wound infection. Although this study has not been repeated, its findings were accepted by a number of cardiac surgeons who have adopted the routine use of topical vancomycin powder to prevent mediastinitis after CPB (unpublished data). The risk of vancomycin resistance has been a concern of those who have adopted this approach. However, 2 factors have supported the use of vancomycin for this purpose. First, the drug is instilled in a confined space, which prevents free movements of organisms in and out of the area at risk. Second, topical application of vancomycin was believed to result in insignificant serum levels. We have studied the pharmacokinetics of vancomycin powder instilled between the edges of the sternum during closure of the median sternotomy in 4 patients undergoing CPB. Contrary to the common belief that topical vancomycin powder is poorly absorbed, levels up to 4.4 mg/L were found in the patients’ serum within 3 to 4 hours after topical application of 1 g of vancomycin powder (Fig 1). Recent emergence of vancomycin resistance in methicillin-resistant S aureus3Hiramatsu K Kanaki H Ino T Yabuta K Oguri T Tenover FC Methicillin-resistant Staphylococcus aureus clinical strain with reduced vancomycin susceptibility.J Antimicrob Chemother. 1997; 40: 135-136Crossref PubMed Scopus (1664) Google Scholar, 4Smith TL Pearson ML Wilcox KR et al.Emergence of vancomycin resistance in methicillin-resistant Staphylococcus aureus.N Engl J Med. 1999; 340: 493-501Crossref PubMed Scopus (993) Google Scholar, 5Sieradzki K Roberts RB Haber SW Tomaasz A The development of vancomycin resistance in a patient with methicillin-resistant Staphylococcus aureus infection.N Engl J Med. 1999; 340: 517-523Crossref PubMed Scopus (593) Google Scholar could raise doubts regarding the wisdom of continuing this approach. The first report of vancomycin resistance in methicillin-resistant S aureus occurred after a cardiac operation in a 4-month-old boy.3Hiramatsu K Kanaki H Ino T Yabuta K Oguri T Tenover FC Methicillin-resistant Staphylococcus aureus clinical strain with reduced vancomycin susceptibility.J Antimicrob Chemother. 1997; 40: 135-136Crossref PubMed Scopus (1664) Google Scholar More recently, Smith and colleagues4Smith TL Pearson ML Wilcox KR et al.Emergence of vancomycin resistance in methicillin-resistant Staphylococcus aureus.N Engl J Med. 1999; 340: 493-501Crossref PubMed Scopus (993) Google Scholar have identified 2 more cases of S aureus with intermediate resistance to vancomycin. The mechanism of resistance, however, is not due to the acquisition of the feared vanA or vanB resistance genes that have been isolated from vancomycin-resistant enterococci.5Sieradzki K Roberts RB Haber SW Tomaasz A The development of vancomycin resistance in a patient with methicillin-resistant Staphylococcus aureus infection.N Engl J Med. 1999; 340: 517-523Crossref PubMed Scopus (593) Google ScholarS aureus –intermediate resistance to vancomycin is believed to be mediated by accumulation of cell wall components, with possible alternative vancomycin-binding pathways that divert vancomycin from its target site. We wish to debate this issue among the cardiothoracic surgeons and the experts in the field of antibiotic resistance. Such a debate will undoubtedly help to determine the risks versus the benefits of using topical vancomycin to prevent mediastinitis after median sternotomy.