[Rational antibiotic treatment of mediastinitis]

Abstract

Mediastinitis occurs as a severe complication of thoracic and cardiac surgical interventions and is the result of traumatic esophageal perforation, conducted infections or as a result of lymphogenic and hematogenic spread of specific infective pathogens. Treatment must as a rule be accompanied by antibiotics, whereby knowledge of the spectrum of pathogens depending on the pathogenesis is indispensable for successful antibiotic therapy. Polymicrobial infections with a high proportion of anaerobes are found in conducted infections of the mediastinum and after esophageal perforation. After cardiac surgery Staphylococci are the dominant pathogens and a nasal colonization with Staphylococcus aureus seems to be a predisposing risk factor. Fungi are the predominant pathogens in immunocompromised patients with consumptive underlying illnesses and can cause acute or chronic forms with granulomatous inflammation. Resistant pathogens are increasingly being found in high-risk patient cohorts, which must be considered for a calculated therapy. For calculated antibiotic therapy the administration of broad spectrum antibiotics, mostly beta-lactams alone or combined with metronidazole is the therapy of choice for both Gram-positive and Gram-negative bacteria inclusive of anaerobes. For patients at risk, additional antibiotic classes with a spectrum against methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) can be administered. Increasing rates of multidrug-resistant Gram-negative bacteria (e.g. Enterobacteriaceae) and non-fermenting bacteria (e.g. Pseudomonas and Acinetobacter) in individual cases necessitates the use of polymyxins (e.g. colistin), new tetracyclines (e.g. glycylglycines) and newly developed combinations of beta-lactams and beta-lactam inhibitors. For treatment of fungal infections (e.g. Candida, Aspergillus and Histoplasma) established and novel azoles, amphotericin B and echinocandins seem to be successful; however, detection of Candida, particularly in mixed infections does not always necessitate treatment. Mediastinitis is still a severe infectious disease with a high mortality, which necessitates an early and broad spectrum antibiotic therapy; however, with respect to optimal duration of therapy and selection of antibiotics, data from good quality comparative studies are lacking.

Keywords: Bacteria; Fungi; Infection; Methicillin; Vancomycin.